Science over the World

November 20, 2023

• Materials Today -- News Triangular material hosts quantum spin liquid

  Data from the teams neutron scattering experiments showed strong correlations between KYbSe2 and the simulated spectrum of a quantum spin liquid state. Image: Allen Scheie/Los Alamos National Laboratory, U.S. Dept. of Energy.

  In 1973, physicist Phil Anderson hypothesized that the quantum spin liquid (QSL) state existed in some triangular atomic lattices, but he lacked the tools to delve deeper. Fifty years later, a team led by researchers associated with the Quantum Science Center (QSC), headquartered at the US Department of Energy (DOE)’s Oak Ridge National Laboratory (ORNL), has confirmed the presence of QSL behavior in a new material with a triangular structure – KYbSe₂. The researchers report their findings in a paper in Nature Physics.

  QSLs – an unusual state of matter controlled by interactions among entangled, or intrinsically linked, magnetic atoms called spins – excel at stabilizing quantum mechanical activity in KYbSe₂ and other delafossites. These materials are prized for their layered triangular lattices and promising properties that could contribute to the construction of high-quality superconductors and quantum computing components.

  “Researchers have studied the triangular lattice of various materials in search of QSL behavior,” said Allen Scheie, a staff scientist at Los Alamos National Laboratory, QSC member and lead author of the paper. “One advantage of this one is that we can swap out atoms easily to modify the material’s properties without altering its structure, and this makes it pretty ideal from a scientific perspective.”

  Using a combination of theoretical, experimental and computational techniques, the team observed multiple hallmarks of QSLs in KYbSe₂: quantum entanglement, exotic quasiparticles and the right balance of exchange interactions, which control how a spin influences its neighbors. Although efforts to identify these features have historically been hindered by the limitations of physical experiments, modern neutron scattering instruments can produce accurate measurements of complex materials at the atomic level.

  By examining KYbSe₂’s spin dynamics with the Cold Neutron Chopper Spectrometer at ORNL’s Spallation Neutron Source (SNS) – a DOE Office of Science user facility – and comparing the results to trusted theoretical models, the researchers found evidence that the material was close to the quantum critical point at which QSL characteristics thrive. They then analyzed its single-ion magnetic state with SNS’s Wide-Angular-Range Chopper Spectrometer.

  The evidence comes in the form of one-tangle, two-tangle and quantum Fisher information, which played a key role in previous QSC research examining a 1D spin chain, or a single line of spins within a material. KYbSe₂ is a 2D system, a quality that made these endeavors more complex.

  “We are taking a co-design approach, which is hardwired into the QSC,” said Alan Tennant, a professor of physics and materials science and engineering at the University of Tennessee, Knoxville, who leads a quantum magnets project for the QSC. “Theorists within the center are calculating things they haven’t been able to calculate before, and this overlap between theory and experiment enabled this breakthrough in QSL research.”

  This study aligns with the QSC’s priorities, which include connecting fundamental research to quantum electronics, quantum magnets and other current and future quantum devices.

  “Gaining a better understanding of QSLs is really significant for the development of next-generation technologies,” Tennant said. “This field is still in the fundamental research state, but we can now identify which materials we can modify to potentially make small-scale devices from scratch.”

  Although KYbSe₂ is not a true QSL, the fact that about 85% of its magnetism fluctuates at low temperature means that it has the potential to become one. The researchers anticipate that slight alternations to its structure or exposure to external pressure could potentially help it reach 100%.

  QSC experimentalists and computational scientists are planning parallel studies and simulations focused on delafossite materials, but the researchers’ findings establish an unprecedented protocol that can also be applied to the study of other systems. By streamlining evidence-based evaluations of QSL candidates, they aim to accelerate the search for genuine QSLs.

  “The important thing about this material is that we’ve found a way to orient ourselves on the map so to speak and show what we’ve gotten right,” Scheie said. “We’re pretty sure there’s a full QSL somewhere within this chemical space, and now we know how to find it.”

  This story is adapted from material from Oak Ridge National Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New 3D-printing system can watch itself print with multiple materials

  Using the new 3D inkjet printing system, researchers produced a functional, tendon-driven robotic hand with 19 independently actuatable tendons, soft fingers with sensor pads, and rigid, load-bearing bones. Photo courtesy of Wojciech Matusik, Robert Katzschmann, Thomas Buchner, et al.

  Using 3D inkjet printing systems, engineers can fabricate hybrid structures with soft and rigid components, like robotic grippers that are strong enough to grasp heavy objects but soft enough to interact safely with humans.

  These multimaterial 3D printing systems utilize thousands of nozzles to deposit tiny droplets of resin, which are smoothed with a scraper or roller and cured with UV light. But the smoothing process can squish or smear resins that cure slowly, limiting the types of materials that can be used.

  Now, researchers from Massachusetts Institute of Technology (MIT), the MIT spinout Inkbit and ETH Zurich in Switzerland have developed a new 3D inkjet printing system that can work with a much wider range of materials. Their printer utilizes computer vision to automatically scan the 3D printing surface and adjust the amount of resin each nozzle deposits in real time to ensure no areas have too much or too little material.

  Since it does not require mechanical parts to smooth the resin, this contactless system works with materials that cure more slowly than the acrylates that are traditionally used in 3D printing. Some slower-curing material chemistries can offer improved performance over acrylates, such as greater elasticity, durability or longevity.

  In addition, the automatic system can make adjustments without stopping or slowing the printing process, making this production-grade printer about 660 times faster than a comparable 3D inkjet printing system.

  The researchers used this printer to create complex, robotic devices that combine soft and rigid materials. For example, they made a completely 3D-printed robotic gripper shaped like a human hand and controlled by a set of reinforced, yet flexible, tendons.

  “Our key insight here was to develop a machine-vision system and completely active feedback loop,” says Wojciech Matusik, a professor of electrical engineering and computer science at MIT who leads the Computational Design and Fabrication Group within the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL). “This is almost like endowing a printer with a set of eyes and a brain, where the eyes observe what is being printed, and then the brain of the machine directs it as to what should be printed next.”

  Matusik is co-corresponding author of a paper on this work in Nature. He is joined on the paper by lead author Thomas Buchner, a doctoral student at ETH Zurich, and co-corresponding author Robert Katzschmann, an assistant professor of robotics who leads the Soft Robotics Laboratory at ETH Zurich, as well as others at ETH Zurich and Inkbit.

  This paper builds off a low-cost, multimaterial 3D printer known as MultiFab that the researchers introduced in 2015. By utilizing thousands of nozzles to deposit tiny droplets of resin that are UV-cured, MultiFab can perform high-resolution 3D printing with up to 10 materials at once.

  With this new project, the researchers sought a contactless process that would expand the range of materials the 3D printer could use, thereby allowing it to fabricate more complex objects.

  They developed a technique, known as vision-controlled jetting, which utilizes four high-frame-rate cameras and two lasers that rapidly and continuously scan the print surface. These cameras capture images as the thousands of nozzles deposit tiny droplets of resin.

  The computer vision system converts the images into a high-resolution depth map, a computation that takes less than a second to perform. It then compares the depth map to the CAD (computer-aided design) model of the part being fabricated and adjusts the amount of resin being deposited to keep the object on target with the final structure.

  The automated system can make adjustments to any individual nozzle. Since the printer has 16,000 nozzles, the system can control fine details of the object being fabricated.

  “Geometrically, it can print almost anything you want made of multiple materials,” says Katzschmann. “There are almost no limitations in terms of what you can send to the printer, and what you get is truly functional and long-lasting.”

  The level of control afforded by the system allows it to print very precisely with wax, which can thus be used as a support material to create cavities or intricate networks of channels inside an object. The wax is printed below the structure as the object is fabricated. After it is complete, the object is heated so the wax melts and drains out, leaving a network of open channels.

  Because it can automatically and rapidly adjust the amount of material being deposited by each of the nozzles in real time, the system doesn’t need to drag a mechanical part across the print surface to keep it level. This allows the printer to use materials that cure more gradually, which would be smeared by a scraper.

  As a demonstration, the researchers used the system to print with thiol-based materials, which are slower-curing than the traditional acrylic materials used in 3D printing. However, thiol-based materials are more elastic and don’t break as easily as acrylates. They also tend to be more stable over a wider range of temperatures and don’t degrade as quickly when exposed to sunlight.

  “These are very important properties when you want to fabricate robots or systems that need to interact with a real-world environment,” says Katzschmann.

  The researchers used thiol-based materials and wax to fabricate several complex devices that would otherwise be nearly impossible to make with existing 3D printing systems. For one, they produced a functional, tendon-driven robotic hand with 19 independently actuatable tendons, soft fingers with sensor pads, and rigid, load-bearing bones.

  “We also produced a six-legged walking robot that can sense objects and grasp them, which was possible due to the system’s ability to create airtight interfaces of soft and rigid materials, as well as complex channels inside the structure,” says Buchner.

  The team also showcased the technology through a heart-like pump with integrated ventricles and artificial heart valves, as well as metamaterials that can be programmed to have non-linear material properties.

  “This is just the start,” Matusik says. “There is an amazing number of new types of materials you can add to this technology. This allows us to bring in whole new material families that couldn’t be used in 3D printing before.”

  The researchers are now looking at using the system to print with hydrogels, which are used in tissue-engineering applications, as well as silicon materials, epoxies and special types of durable polymers. They also want to explore new application areas, such as printing customizable medical devices, semiconductor polishing pads and even more complex robots.

  This story is adapted from material from MIT, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 17, 2023

• Materials Today -- News Laser light shows up true character of metamaterials

  This optical micrograph shows an array of microscopic metamaterial samples on a reflective substrate. Laser pulses have been digitally added, depicting pump (red) and probe (green) pulses characterizing a sample in the center. Image courtesy of Carlos Portela, Yun Kai, et al.

  Metamaterials are products of engineering wizardry. They are made from everyday polymers, ceramics and metals. And when constructed precisely at the microscale, in intricate architectures, these ordinary materials can take on extraordinary properties.

  With the help of computer simulations, engineers can play with any combination of microstructures to see how certain materials can transform, for instance, into sound-focusing acoustic lenses or lightweight, bulletproof films.

  But simulations can only take a design so far. To know for sure whether a metamaterial will meet expectations, physically testing them is a must. But there’s been no reliable way to push and pull on metamaterials at the microscale, and to know how they will respond, without contacting and physically damaging the structures in the process.

  Now, a new laser-based technique offers a safe and fast solution that could speed up the discovery of promising metamaterials for real-world applications.

  The technique, developed by engineers at Massachusetts Institute of Technology (MIT), probes metamaterials with a system of two lasers. One laser quickly zaps a structure while the other measures the ways in which it vibrates in response, much like striking a bell with a mallet and recording its reverb. In contrast to a mallet, however, the lasers make no physical contact with the metamaterials. Yet they can still produce vibrations throughout a metamaterial’s tiny beams and struts, as if the structure were being physically struck, stretched or sheared.

  The engineers can use the resulting vibrations to calculate various dynamic properties of the material, such as how it would respond to impacts and how it would absorb or scatter sound. With an ultrafast laser pulse, they can excite and measure hundreds of miniature structures within minutes. For the first time, the new technique offers a safe, reliable and high-throughput way to dynamically characterize microscale metamaterials.

  “We need to find quicker ways of testing, optimizing and tweaking these materials,” says Carlos Portela, professor in mechanical engineering at MIT. “With this approach, we can accelerate the discovery of optimal materials, depending on the properties you want.”

  Portela and his colleagues detail their new system, which they’ve named LIRAS (laser-induced resonant acoustic spectroscopy), in a paper in Nature. His MIT co-authors include first author Yun Kai, Somayajulu Dhulipala, Rachel Sun, Jet Lem and Thomas Pezeril, along with Washington DeLima at the US Department of Energy’s Kansas City National Security Campus.

  The metamaterials that Portela works with are made from common polymers. Via 3D printing, these polymers are formed into tiny, scaffold-like towers made from microscopic struts and beams. Each tower is patterned by repeating and layering a single geometric unit, such as an eight-pointed configuration of connecting beams. When stacked end to end, the tower arrangement can give the whole polymer properties that it would not otherwise have.

  But engineers are severely limited in their options for physically testing and validating these metamaterial properties. Nanoindentation is the typical way in which such microstructures are probed, though in a very deliberate and controlled fashion. This method uses a micrometer-scale tip to slowly push down on a structure while measuring the tiny displacement and forces on the structure as it’s compressed.

  “But this technique can only go so fast, while also damaging the structure,” Portela notes. “We wanted to find a way to measure how these structures would behave dynamically – for instance, in the initial response to a strong impact – but in a way that would not destroy them.”

  The team turned to laser ultrasonics – a nondestructive method that uses a short laser pulse tuned to ultrasound frequencies to excite very thin materials such as gold films without physically touching them. The ultrasound waves created by the laser excitation are within a range that can cause a thin film to vibrate at a frequency that scientists then use to determine the film’s exact thickness down to nanometer precision. The technique can also be used to determine whether a thin film holds any defects.

  Portela and his colleagues realized that ultrasonic lasers might also safely induce their 3D metamaterial towers to vibrate. The height of the towers – which range from 50µm to 200µm — is on a similar microscopic scale to the thin films.

  To test this idea, Yun Kai, who joined Portela’s group with expertise in laser optics, built a tabletop setup comprising two ultrasonic lasers – a ‘pulse’ laser to excite metamaterial samples and a ‘probe’ laser to measure the resulting vibrations.

  On a single chip no bigger than a fingernail, the team printed hundreds of microscopic towers, each with a specific height and architecture. They placed this miniature city of metamaterials in the two-laser setup, then excited the towers with repeated ultrashort pulses. The second laser measured the vibrations from each individual tower. The team then gathered the data and looked for patterns in the vibrations.

  “We excite all these structures with a laser, which is like hitting them with a hammer,” Portela explains. “And then we capture all the wiggles from hundreds of towers, and they all wobble in slightly different ways. Then we can analyze these wiggles and extract the dynamic properties of each structure, such as their stiffness in response to impact and how fast ultrasound travels through them.”

  The team used the same technique to scan the towers for defects. They printed several defect-free towers and then printed the same architectures with varying degrees of defects, such as missing struts and beams, each smaller than the size of a red blood cell.

  “Since each tower has a vibrational signature, we saw that the more defects we put into that same structure, the more this signature shifted,” Portela says. “You could imagine scanning an assembly line of structures. If you detect one with a slightly different signature, you know it’s not perfect.”

  He says scientists can easily recreate the laser setup in their own labs, and predicts this would cause the discovery of practical, real-world metamaterials to take off. For his part, Portela is keen to fabricate and test metamaterials that focus ultrasound waves, which could be used to boost the sensitivity of ultrasound probes. He’s also exploring impact-resistant metamaterials, which could be used to line the inside of bike helmets.

  “We know how important it is to make materials to mitigate shock and impacts,” Kai says. “Now with our study, for the first time we can characterize the dynamic behavior of metamaterials and explore them to the extreme.”

  This story is adapted from material from MIT, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Unexpected twist to tweaking non-chiral polymers

  This optical micrograph shows the chiral liquid crystal phase of a polymer that researchers are exploring to produce highly efficient semiconductor materials. Image courtesy Ying Diao Lab.

  A new study led by chemists at the University of Illinois at Urbana-Champaign brings fresh insight into the development of semiconductor materials that can do things their traditional silicon counterparts cannot – harness the power of chirality, a non-superimposable mirror image.

  Chirality is one of the strategies that nature uses to build complexity into structures. The DNA double helix is perhaps the most recognized example of chirality – two molecule chains connected by a molecular ‘backbone’ and twisted to the right.

  In nature, chiral molecules, like proteins, funnel electricity very efficiently by selectively transporting electrons of the same spin direction. Researchers have been working for decades to mimic nature’s chirality in synthetic molecules.

  A new study, led by chemical and biomolecular chemistry professor Ying Diao, investigates how making various modifications to a non-chiral polymer called DPP-T4 can be used to form chiral helical structures in polymer-based semiconductor materials. Potential applications of this work include solar cells that function like leaves, computers that use quantum states of electrons to compute more efficiently and new imaging techniques that capture three-dimensional information rather than two-dimensional, to name a few. The chemists report their findings in a paper in ACS Central Science.

  “We started by thinking that making small tweaks to the structure of the DPP-T4 molecule – achieved by adding or changing the atoms connected to the backbone – would alter the torsion, or twist of the structure, and induce chirality,” Diao said. “However, we quickly discovered that things were not that simple.”

  Using X-ray scattering and imagining, the team found that their ‘slight tweaks’ caused major changes in the phases of the material.

  “What we observed is a sort of Goldilocks effect,” Diao said. “Usually, the molecules assemble like a twisted wire, but suddenly, when we twist the molecule to a critical torsion, they started to assemble into new mesophases in the form of flat plates or sheets. By testing to see how well these structures could bend polarized light – a test for chirality – we were surprised to discover that the sheets can also twist into cohesive chiral structures.”

  The team’s findings illustrate the fact that not all polymers will behave similarly when they are tweaked to mimic the efficient electron transport of chiral structures. The study demonstrates that it is critical not to overlook the formation of complex mesophase structures, which can lead to the discovery of unknown phases with previously unimagined optical, electronic and mechanical properties.

  This story is adapted from material from the University of Illinois at Urbana-Champaign, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 16, 2023

• Materials Today -- News Graphene sheet gives boost to lithium-oxygen batteries

  Synthesis of a free-standing and edge-site-free GMS-sheet with hierarchically porous structure. Image: Wei Yu, Hirotomo Nishihara et al.

  Lithium-air batteries, sometimes known as lithium-oxygen batteries (Li-O₂), comprise a lithium metal anode, an organic electrolyte and a porous carbon cathode. During discharge, oxygen in the surrounding air reacts with lithium at the cathode, releasing energy in the process. Given their extremely high energy density, Li-O₂ batteries could potentially lead the way in generating greener sources for energy security.

  Yet advances in the technology have stalled because the specially designed carbon cathodes lack certain characteristics. Namely, abundant active sites where chemical reactions can take place and space large enough to accommodate the nucleation and growth of discharge products, something necessary for achieving a high energy density.

  Now, researchers from Tohoku University in Japan and their partners have developed a special type of porous carbon sheet called a graphene mesosponge sheet (GMS-sheet) for use as a cathode. This novel sheet, reported in a paper in Advanced Energy Materials, could significantly improve the energy density and cycle stability of Li-O₂ batteries.

  "The rational design of the porous structure for the carbon cathode is crucial for achieving a high-performance, but it is also a major challenge," says Hirotomo Nishihara, professor at Tohoku University's Advanced Institute for Materials Research (WPI-AIMR) and co-corresponding author of the paper. "We creatively developed an angstrom-to-millimeter controllable synthesis of free-standing cathodes with minimally stacked graphene free from edge sites."

  To do this, Nishihara and his colleagues utilized a chemical vapor deposition (CVD) process and rationally controlled three synthesis parameters: the pelletization force, the amount of aluminum oxide (Al₂O₃) template and the CVD's duration. Doing so resulted in a series of GMS-sheets with different porosity, thickness and number of carbon layers.

  "It is interesting to see that the specific mass/areal capacities of Li-O₂ batteries using GMS-sheets cathodes can be controlled by these three synthesis parameters," says Wei Yu, assistant professor at Tohoku University's WPI-AIMR and co-corresponding author of the paper. "By optimizing these parameters, we're excited to achieve impressive energy-storage capacities, surpassing the performance of the best carbon cathodes, with more than 6300 milliampere-hours per gram and more than 30.0 milliampere-hours per square centimeter when normalized to the mass and area of GMS-sheets, respectively.

  "With the help of our collaborators from the National Institute for Materials Science, Ochanomizu University, Hokkaido University, Osaka University, and 3DC Inc., we characterized the discharge-charge mechanism using comprehensive in situ techniques and unlocked the key to superior battery performance: the hierarchical porous structure of GMS-sheet."

  Nishihara and his team believe that the GMS-sheet represents a milestone carbon cathode for Li-O₂ batteries. "We will continue to promote the practical use of Li-O₂ batteries based on our GMS-sheet, and our landscape also covers other metal-gas batteries such as Na-O₂, Li-CO₂ and Zn-O₂ batteries, for which a high-performance carbon cathode is also needed," says Nishihara.

  This story is adapted from material from Tohoku University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New dimension in computer processors

  The novel in-memory processor that contains more than 1000 transistors made from a 2D semiconductor material. Photo: 2023 EPFL/Alan Herzog.

  As information and communication technologies (ICT) process data, they convert electricity into heat. Already today, the global ICT ecosystem’s carbon dioxide footprint rivals that of aviation. It turns out, however, that a big part of the energy consumed by computer processors doesn’t go into performing calculations. Instead, the bulk of the energy used to process data is spent shuttling bytes between the memory and the processor.

  Now, in a paper in Nature Electronics, researchers from the Laboratory of Nanoscale Electronics and Structures (LANES) at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland report a new processor that tackles this inefficiency by integrating data processing and storage onto a single device, a so-called in-memory processor. This processor breaks new ground because it contains more than 1000 transistors made from a two-dimensional (2D) semiconductor material, a key milestone on the path to industrial production.

  According to Andras Kis, who led the study, the main culprit behind the inefficiency of today’s CPUs is the universally adopted von Neumann architecture. Specifically, the physical separation of the components used to perform calculations and to store data. Because of this separation, processors need to retrieve data from the memory to perform calculations, which involves moving electrical charges, charging and discharging capacitors, and transmitting currents along lines – all of which dissipate energy.

  Until around 20 years ago, this architecture made sense, as different types of devices were required for data storage and processing. But the von Neumann architecture is increasingly being challenged by more efficient alternatives.

  “Today, there are ongoing efforts to merge storage and processing into more universal in-memory processors that contain elements which work both as a memory and as a transistor,” says Kis. His lab has been exploring ways to achieve this goal using molybdenum disulfide (MoS₂), a 2D semiconductor material.

  In the paper, Guilherme Migliato Marega, a doctoral assistant at LANES, and his co-authors describe an MoS₂-based in-memory processor dedicated to one of the fundamental operations in data processing: vector-matrix multiplication. This operation is ubiquitous in digital signal processing and the implementation of artificial intelligence (AI) models. Improvements in its efficiency could yield substantial energy savings throughout the entire ICT sector.

  Their novel processor combines 1024 elements onto a 1cm-by-1cm chip. Each element comprises a 2D MoS₂ transistor and a floating gate, which stores a charge in its memory that controls the conductivity of each transistor. Coupling processing and memory in this way fundamentally changes how the processor carries out the calculation.

  “By setting the conductivity of each transistor, we can perform analog vector-matrix multiplication in a single step by applying voltages to our processor and measuring the output,” explains Kis.

  The choice of material – MoS₂ – played a vital role in the development of the in-memory processor. For one, MoS₂ is a semiconductor – a requirement for the development of transistors. But unlike silicon, the most widely used semiconductor in today’s computer processors, MoS₂ forms a stable monolayer, just three atoms thick, that only interacts weakly with its surroundings. This thinness offers the potential to produce extremely compact devices.

  MoS₂ is also a material that Kis’s lab knows well. In 2010, they created their first single MoS₂ transistor using a monolayer of the material peeled off a crystal using Scotch tape.

  Over the past 13 years, their processes have matured substantially, with Migliato Marega’s contributions playing a key role. “The key advance in going from a single transistor to over 1000 was the quality of the material that we can deposit,” says Kis. “After a lot of process optimization, we can now produce entire wafers covered with a homogenous layer of uniform MoS₂. This lets us adopt industry-standard tools to design integrated circuits on a computer and translate these designs into physical circuits, opening the door to mass production.”

  Aside from its purely scientific value, Kis sees this result as a testament to the importance of close scientific collaboration between Switzerland and the EU. Particularly in the context of the European Chips Act, which aims to bolster Europe’s competitiveness and resilience in semiconductor technologies and applications.

  “EU funding was crucial for both this project and those that preceded it, including the one that financed the work on the first MoS₂ transistor, showing just how important it is for Switzerland,” he says.

  “At the same time, it shows how work carried out in Switzerland can benefit the EU as it seeks to reinvigorate electronics fabrication. Rather than running the same race as everyone else, the EU could, for example, focus on developing non-von Neumann processing architectures for AI accelerators and other emerging applications. By defining its own race, the continent could get a head start to secure a strong position in the future.”

  This story is adapted from material from EPFL, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 15, 2023

• Materials Today -- News New ‘cooling glass’ blasts heat into space

  UMD researchers hold up a sample of the new cooling coating. Photo: University of Maryland.

  Researchers at the University of Maryland (UMD) aiming to combat rising global temperatures have developed a new ‘cooling glass’ that can turn down the heat indoors without electricity by drawing on the cold depths of space.

  The new technology, a microporous glass coating, can lower the temperature of the material beneath it by 3.5°C at noon. According to researchers, led by Liangbing Hu in the Department of Materials Science and Engineering, the coating has the potential to reduce a mid-rise apartment building’s yearly carbon emissions by 10%. The team report this ‘cooling glass’ in a paper in Science.

  The coating works in two ways. First, it reflects up to 99% of solar radiation to stop buildings from absorbing heat. More intriguingly, it emits heat into the icy universe, where the temperature is generally around -270°C, or just a few degrees above absolute zero, in the form of longwave infrared radiation.

  In a phenomenon known as ‘radiative cooling’, space effectively acts as a heat sink for the buildings. The researchers take advantage of the new cooling glass design along with the so-called atmospheric transparency window –a part of the electromagnetic spectrum that passes through the atmosphere without boosting its temperature – to dump large amounts of heat into the infinite cold sky beyond. (The same phenomenon allows the Earth to cool itself, particularly on clear nights, although with much less intense emissions than those from the new glass developed at UMD.)

  “It’s a game-changing technology that simplifies how we keep buildings cool and energy-efficient,” said Xinpeng Zhao, an assistant research scientist and first author of the paper. “This could change the way we live and help us take better care of our home and our planet."

  Unlike previous attempts at cooling coatings, the new UMD-developed glass is environmentally stable – able to withstand exposure to water, ultraviolet radiation, dirt and even flames, and enduring temperatures of up to 1000°C. The glass can be applied to a variety of surfaces, including tile, brick and metal, making it highly scalable and adoptable for wide use.

  The team used finely ground glass particles as a binder, allowing them to avoid polymers and enhance the long-term outdoor durability of the glass. They chose the particle size to maximize the emission of infrared heat while simultaneously reflecting sunlight.

  The development of the cooling glass aligns with global efforts to cut energy consumption and fight climate change, said Hu, pointing to recent reports that this year’s Fourth of July fell on what may have been the hottest day globally in 125,000 years.

  "This 'cooling glass' is more than a new material – it's a key part of the solution to climate change,” he said. “By cutting down on air conditioning use, we're taking big steps toward using less energy and reducing our carbon footprint. It shows how new technology can help us build a cooler, greener world."

  The team is now focusing on both further testing and practical applications of their cooling glass. They are optimistic about its commercialization prospects and have created a startup company called CeraCool to scale up and commercialize it.

  This story is adapted from material from the University of Maryland, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New ceramic cools off in the sun

  The cooling ceramic can be produced in different colors, meeting aesthetic requirements. Photo: City University of Hong Kong.

  A significant breakthrough in developing a passive radiative cooling (PRC) material has been made by researchers at the City University of Hong Kong (CityU). They report their advance in a paper in Science.

  The novel material, known as cooling ceramic, displays high-performance optical properties for energy-free and refrigerant-free cooling. Its cost-effectiveness, durability and versatility make it highly suitable for commercialization in numerous applications, particularly building construction.

  By reducing the thermal load of buildings and providing stable cooling performance, in diverse weather conditions and all climates, cooling ceramic can enhance energy efficiency and help to combat global warming.

  According to Chi-yan Tso, associate professor in the School of Energy and Environment (SEE) at CityU and one of the corresponding authors of the paper, PRC is considered one of the most promising green cooling technologies for curbing soaring demand for space cooling. However, current PRC technologies that use nanophotonic structures are limited by their high cost and poor compatibility with existing end uses, while polymeric photonic alternatives lack weather resistance and effective solar reflection.

  “But our cooling ceramic achieves advanced optical properties and has robust applicability,” said Tso. “The color, weather resistance, mechanical robustness and ability to depress the Leidenfrost effect – a phenomenon that prevents heat transfer and makes liquid cooling on the hot surface ineffective – are key features ensuring the durable and versatile nature of the cooling ceramic.”

  The cooling ceramic's extraordinary abilities are due to its hierarchically porous structure, which is easily fabricated using highly accessible inorganic materials such as alumina through a simple two-step process involving phase inversion and sintering. No delicate equipment or costly materials are required, making the large-scale manufacturing of cooling ceramics highly feasible.

  Optical properties determine the cooling performance of PRC materials in two wavelength ranges: the solar range (0.25–2.5µm) and the mid-infrared range (8–13µm). Efficient cooling requires high reflectivity in the former range to minimize solar heating and high emissivity in the latter range to maximize radiative heat dissipation. Owing to the high bandgap of alumina, the cooling ceramic keeps solar absorption to a minimum.

  In addition, by mimicking the bio-whiteness of the Cyphochilus beetle and optimizing the porous structure, the cooling ceramic can efficiently scatter almost all the wavelengths of sunlight, resulting in near-ideal solar reflectivity of 99.6% (a record high solar reflectivity) and a high mid-infrared thermal emission of 96.5%. These advanced optical properties surpass those of current state-of-the-art materials.

  “The cooling ceramic is made of alumina, which provides the desired UV resistance degradation, which is a concern typical of most polymer-based PRC designs,” said Tso. “It also exhibits outstanding fire resistance by withstanding temperatures exceeding 1000°C, which surpasses the capabilities of most polymer-based or metal-based PRC materials.”

  Beyond its exceptional optical performance, the cooling ceramic also exhibits excellent weather resistance, chemical stability and mechanical strength, making it ideal for long-term outdoor use. At extremely high temperatures, the cooling ceramic exhibits superhydrophilicity, which causes immediate droplet spreading, while its interconnected porous structure helps to soak up the droplets. This superhydrophilic characteristic also inhibits the Leidenfrost effect, which hinders evaporation and is commonly found in traditional building envelope materials, leading to efficient evaporative cooling.

  The Leidenfrost effect is a phenomenon that occurs when a liquid is brought into contact with a surface significantly hotter than its boiling point. Instead of immediately boiling away, the liquid forms a vapor layer that insulates it from direct contact with the surface. This vapor layer reduces the rate of heat transfer and makes liquid cooling on the hot surface ineffective, causing the liquid to levitate and skid across the surface.

  “The beauty of the cooling ceramic is that it fulfils the requirements for both high-performance PRC and applications in real-life settings,” said Tso, adding that the cooling ceramic can be colored with a dual-layer design to meet aesthetic requirements.

  “Our experiment found that applying the cooling ceramic on a house roof can achieve more than 20% electricity for space cooling, which confirms the great potential of cooling ceramic in reducing people’s reliance on traditional active cooling strategies and provides a sustainable solution for avoiding electricity grid overload, greenhouse gas emissions and urban heat islands.”

  Tso and his research team now intend to advance further passive thermal management strategies. They aim to explore using these strategies to enhance energy efficiency, promote sustainability and increase the accessibility and applicability of PRC technologies in various sectors, including textiles, energy systems and transportation.

  This story is adapted from material from the City University of Hong Kong, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Wrocław University of Science and Technology Honorary doctorate of the Wroclaw Tech for prof. Marja Makarow
  The eminent Finnish biochemist and molecular biologist from the University of Helsinki, as well as president of Academia Europaea, received an honorary doctorate from our university.
• Wrocław University of Science and Technology Lem Prize 2023 awarded to Professor Ido Kaminer
  Experimental physicist Prof Ido Kaminer (Technion Israel Institute of Technology) with the Stanisław Lem European Science Prize for 2023. The chapter's decision was announced during the Celebration of Wrocław University of Science and Technology Day.

November 14, 2023

• Materials Today -- News New technique lights up polymer composition

  Every monomer that goes in gives off a puff of light. The light is induced by a laser, and the puff of light has a color. In our case, its either green or yellow. By seeing whether its yellow or green, we see what monomer goes in.Peng Chen, Cornell University

  Synthetic polymers are everywhere in our society – from nylon and polyester clothing to Teflon cookware and epoxy glue. At the molecular level, these polymers’ molecules are made of long chains of monomer building blocks.

  While the monomer sequence plays a critical role in a polymer’s properties, scientists have until now lacked a method for sequencing synthetic copolymers, which consist of different types of monomers in the same chain.

  This has changed with the development of CREATS (Coupled REaction Approach Toward Super-resolution imaging) by Peng Chen, professor of chemistry at Cornell University, and his colleagues. Using CREATS, Chen and his colleagues can image polymerization catalysis reactions at single-monomer resolution and, through fluorescent signaling, differentiate monomers from one another. Both are important steps in discovering the molecular composition of a synthetic polymer.

  They report this new technique, and the first discoveries they’ve made with it, in a paper in Nature Chemistry. The co-lead authors are Rong Ye, Xiangcheng Sun and Xianwen Mao, all former postdoctoral researchers in the Chen group. Other co-authors are former Chen group postdoctoral researchers Susil Baral and Chunming Liu, current postdoctoral researcher Felix Alfonso, and Geoffrey Coates, a professor in chemistry and chemical biology.

  “Synthetic polymers are made of monomer units linked together like a string of beads,” said Chen. In the simplest polymers, the monomers are identical, but more complex properties arise when polymers contain monomers of different sorts – called copolymers. The precise arrangement of the monomers in a copolymer plays an important role in determining its properties, such as stiffness or flexibility.

  Sequence plays a role in the properties of natural polymers, too. A protein, for example, is made of 20 amino acid monomers arranged in a very specific sequence.

  “In a natural polymer, nature has control,” Chen said. “In synthetic polymers, humans are making the arrangements, and the chemists generally don’t have that precise control.”

  Sequencing copolymers is difficult in large part because of the heterogeneity of synthetic polymers. Individual chains differ in length, composition and sequence, which requires single-polymer sequencing methods that can resolve and identify individual monomers.

  Some modern methods allow scientists to control the arrangement of monomers in a chain, Chen said, but only for very short polymers – 10 to 20 monomers long.

  Using CREATS, the researchers can determine the sequence of a polymer as it is made, one monomer at a time, by imaging and identifying every single monomer as it is added to the polymer. To make the monomers visible, CREATS couples the polymerization reaction with another reaction that produces fluorescent signals.

  “Every monomer that goes in gives off a puff of light,” Chen said. “The light is induced by a laser, and the puff of light has a color. In our case, it’s either green or yellow. By seeing whether it’s yellow or green, we see what monomer goes in.”

  Chen’s group is already equipped to measure synthetic polymer properties. Now that they can determine the sequence of an individual polymer, a next step is to combine the two experiments to correlate structure and function, ultimately providing guiding principles for the design of polymers with specific properties.

  “If you know how sequence controls property, you can really think about designing whatever sequence you want to achieve a certain property,” Chen said. “This knowledge presumably can help people tailor their materials for a desired application.”

  This story is adapted from material from Cornell University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Wrocław University of Science and Technology How to read NewS in English
  You can read the entire NewS newsletter in English thanks to the automatic translation function built into Gmail.
• Materials Today -- News New hydrogel gelatin patches that improve wound management

   

  Researchers from Incheon National University in South Korea have developed a new type of hydrogel gelatin patch to assist wound management by accelerating healing. The bioactive tissue adhesive patches allow accurate control of adhesion and mechanical properties in wound management and tissue regeneration through adjustable polymeric compositions, and can deliver drugs directly to wounds, aiding recovery.

   

  Open wounds need effective management to speed up the healing process and prevent potential infections. Although sutures and staples are commonly used in wound closure, they can also result in secondary tissue injuries, an unwelcome inflammatory response, and leaking fluids and gases, thereby requiring anesthetics.

   

  A range of tissue adhesive glues can also be a useful alternative to suturing and stapling, but can introduce toxicity and weak adhesion. Although existing adhesive patches containing dopamine also have potential, they pose problems because of slow oxidation and weak bonding with the polymer backbone.

   

  However, as reported in Composites Part B: Engineering [Lee et al. Compos. B: Eng. (2023) DOI: 10.1016/j.compositesb.2023.110951], here a new strategy was devised to produce dopamine-containing tissue adhesive gelatin hydrogels. This was achieved by adding calcium peroxide (CaO₂) in the preparation of the hydrogel solution, producing a gelatin-based oxygen-generating tissue adhesive (GOT) that reacts easily with water to release molecular oxygen. This in turn facilitates the oxidation of dopamine molecules, promoting polymerization and wound healing.

   

  The GOTs are the first reported bioadhesive, as well as being the first tissue adhesive material that can generate oxygen. Much interest has been shown in polymeric adhesive hydrogels as promising wound management materials due to features such as their biocompatibility, tunable properties, delivery of therapeutic agents, and tissue adhesive properties.

   

  The team carried out in vitro and in vivo tests to show how the GOTs improved coagulation, blood closure and neovascularization. These GOTs, as well as their oxygen generation, offered easy control of gelation and mechanical properties, providing strong tissue adhesion.

   

  The mechanical properties of these tissue adhesive patches accelerate the wound healing process as they can be fine-tuned and can be functionalized with healing agents. The team believe their GOTs have the potential to be a new cost-effective solution for wound management in a clinical setting.

   

  As team leader Kyung Min Park said “We would like to pursue clinical trials and commercialization of this material through follow-up research and ultimately contribute to improving the quality of human life by developing next-generation tissue adhesive materials that can be applied to humans”.

  We would like to pursue clinical trials and commercialization of this material through follow-up research and ultimately contribute to improving the quality of human life by developing next-generation tissue adhesive materials that can be applied to humans.Kyung Min Park

November 13, 2023

• Materials Today -- News Chiral dance puts electrons in a spin

  Chiral phonons excited by the circularly polarized terahertz light pulses generate ultrafast magnetization in cerium fluoride. Fluorine ions (red, fuchsia) are set into motion by circularly polarized terahertz light pulses (yellow spiral), where red denotes the ions with the largest motion in the chiral phonon mode. The cerium ion is represented in teal. The compass needle represents the magnetization induced by the rotating atoms. Image courtesy of Mario Norton and Jiaming Luo/Rice University.

  Quantum materials hold the key to a future of lightning-fast, energy-efficient information systems. The problem with tapping their transformative potential is that the vast number of atoms in solids often drowns out the exotic quantum properties that electrons carry.

  Researchers in the lab of quantum materials scientist Hanyu Zhu at Rice University have now found that when they move in circles, atoms can also work wonders. They discovered that when the atomic lattice in a rare-earth crystal becomes animated with a corkscrew-shaped vibration known as a chiral phonon, the crystal is transformed into a magnet.

  According to a paper in Science, exposing cerium fluoride to ultrafast pulses of light sends its atoms into a dance that momentarily enlists the spins of electrons, causing them to align with the atomic rotation. This alignment would otherwise require a powerful magnetic field to activate, seeing as cerium fluoride is naturally paramagnetic, with randomly oriented spins even at zero temperature.

  “Each electron possesses a magnetic spin that acts like a tiny compass needle embedded in the material, reacting to the local magnetic field,” said Boris Yakobson, a materials scientist at Rice University and co-author of the paper. “Chirality ? also called handedness because of the way in which left and right hands mirror each other without being superimposable ? should not affect the energies of the electrons’ spin. But in this instance, the chiral movement of the atomic lattice polarizes the spins inside the material as if a large magnetic field were applied.”

  Though short-lived, the force that aligns the spins outlasts the duration of the light pulse by a significant margin. Since atoms only rotate in particular frequencies and move for a longer time at lower temperatures, additional frequency- and temperature-dependent measurements further confirmed that magnetization occurs as a result of the atoms’ collective chiral dance.

  “The effect of atomic motion on electrons is surprising because electrons are so much lighter and faster than atoms,” said Zhu, an assistant professor of materials science and nanoengineering. “Electrons can usually adapt to a new atomic position immediately, forgetting their prior trajectory. Material properties would remain unchanged if atoms went clockwise or counterclockwise, i.e., traveled forward or backward in time ? a phenomenon that physicists refer to as time-reversal symmetry.”

  The idea that the collective motion of atoms breaks time-reversal symmetry is relatively recent. Chiral phonons have already been experimentally demonstrated in a few different materials, but exactly how they impact material properties is not well understood.

  “We wanted to quantitatively measure the effect of chiral phonons on a material’s electrical, optical and magnetic properties,” Zhu said. “Because spin refers to electrons’ rotation while phonons describe atomic rotation, there is a naive expectation that the two might talk with each other. So we decided to focus on a fascinating phenomenon called spin-phonon coupling.”

  Spin-phonon coupling plays an important part in real-world applications like writing data to a hard disk. Earlier this year, Zhu’s group demonstrated a new instance of spin-phonon coupling in single molecular layers with atoms moving linearly and shaking spins.

  In their new experiments, Zhu and the team members had to find a way to drive a lattice of atoms to move in a chiral fashion. This required that they both pick the right material and create light at the right frequency to send the material’s atomic lattice aswirl, which they achieved with the help of theoretical computation from their collaborators.

  “There is no off-the-shelf light source for our phonon frequencies at about 10 terahertz,” explained Jiaming Luo, an applied physics graduate student and lead author of the paper. “We created our light pulses by mixing intense infrared lights and twisting the electric field to ‘talk’ to the chiral phonons. Furthermore, we took another two infrared light pulses to monitor the spin and atomic motion, respectively.”

  In addition to the insights into spin-phonon coupling derived from the research findings, the experimental design and setup will help inform future research on magnetic and quantum materials.

  “We hope that quantitatively measuring the magnetic field from chiral phonons can help us develop experiment protocols to study novel physics in dynamic materials,” Zhu said. “Our goal is to engineer materials that do not exist in nature through external fields ? such as light or quantum fluctuations.”

  This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Smart contact lens puts glucose monitoring in focus

  Smart contact lens for robust digital diabetes diagnosis.

  Wearable continuous glucose monitoring (CGM) devices promise a new age in diabetes management, that is easy and convenient for patients. Researchers have now developed a smart contact lens that can monitor glucose levels in tears in real time, relaying the information to patients via a smartphone [Han et al., Biomaterials 302 (2023) 122315, https://doi.org/10.1016/j.biomaterials.2023.122315].

  The team from Pohang University of Science and Technology, The Catholic University of Korea, and PHI BIOMED Co. fabricated smart contact lenses with new bimetallic electrodes based on hyaluronate-coated gold-platinum (Au@Pt) that improve long-term stability in the eye.

  “Smart contact lenses for CGM using an electrochemical glucose sensor have suffered from the relatively low stability of electrodes and sensors inadequate for further clinical applications,” explains Sei Kwang Hahn, who led the study.

  Commercial electrochemical glucose sensors typically rely on Pt for working and counter electrodes because of the metal’s excellent electrocatalytic reactivity. When deposited on a polymer substrate, such as poly(ethylene terephthalate) (PET), however, the metal’s lack of ductility and the large difference in thermal expansion coefficients results in cracking that degrades performance and leads ultimately to device failure. The new bimetallic electrodes, produced by alloying Pt with other metals such as Au, get around this shortcoming.

  “We used Au thin film as a stress relaxation layer with a low surface energy and a lattice constant similar to that of Pt,” Hahn explains.

  The reduced difference in thermal expansion coefficients between Au@Pt and PET minimize cracking, while passivation of the Au@Pt bimetallic electrode with branch-type thiolated hyaluronate (HA) improves the stability further by preventing dissolution of Au by Cl^- ions present in tears.

  “[We] increased the stability of smart contact lenses by fabricating thin-film electrodes with minimal physical defects (cracks) and electrochemical defects (Au dissolution),” he points out.

  The new glucose sensor contact lens, which includes an RF system for wireless power supply and an ASIC chip for wireless communication, was tested in diabetic rabbits for three weeks. The level of glucose in tears correlates well with blood glucose levels, even as levels increase and decrease in real time, providing an accurate measure for monitoring diabetes.

  “Our smart contact lens with optimized electrodes enables the accurate and long-term real-time glucose monitoring of normal and diabetic rabbits,” says Hahn. “Smart contact lenses could be better than CGM devices for accurate and long-term stable monitoring of glucose levels for the diagnosis of diabetes,” he suggests.

November 10, 2023

• Materials Today -- News Dissolved metals make effective catalysts

  Liquid gallium in a Petri dish. Photo: University of Sydney/Philip Ritchie.

  Liquid metals could be the long-awaited solution to ‘greening’ the chemical industry, according to researchers who have tested a new technique they hope can replace energy-intensive chemical engineering processes that hark back to the early 20th century.

  Chemical production accounts for approximately 10–15% of total greenhouse gas emissions, while more than 10% of the world’s total energy is used in chemical factories.

  Now, in a paper in Nature Nanotechnology, an Australian research team reports a much-needed innovation that moves away from old, energy-intensive catalysts made from solid materials. The research is led by Kourosh Kalantar-Zadeh, head of the University of Sydney’s School of Chemical and Biomolecular Engineering, and Junma Tang, who works jointly at the University of Sydney and UNSW.

  A catalyst is a substance that makes chemical reactions occur faster and more easily without participating in the reaction. Solid catalysts – typically solid metals or solid compounds of metals – are commonly used in the chemical industry to make plastics, fertilizers, fuels and feedstock. But chemical production using solid catalysts is highly energy intensive, requiring temperatures of up to a 1000°C.

  The new process instead uses liquid metals to dissolve tin and nickel, giving them unique mobility and allowing them to migrate to the surface of the liquid metals and react with input molecules such as canola oil. This results in the rotation, fragmentation and reassembly of the canola oil molecules into smaller organic chains, including propylene, a high-energy fuel crucial for many industries.

  “Our method offers an unparalleled possibility to the chemical industry for reducing energy consumption and greening chemical reactions,” said Kalantar-Zadeh. “It’s expected that the chemical sector will account for more than 20% of emissions by 2050. But chemical manufacturing is much less visible than other sectors – a paradigm shift is vital.”

  Atoms in liquid metals are more randomly arranged and have greater freedom of movement than in solids, making it easier form them to come into contact with chemical compounds and participate in chemical reactions. “Theoretically, they can catalyze chemicals at much lower temperatures – meaning they require far less energy,” explained Kalantar-Zadeh.

  In their study, the researchers dissolved high-melting-point nickel and tin in a gallium-based liquid metal that has a melting point of just 30°C.

  “By dissolving nickel in liquid gallium, we gained access to liquid nickel at very low temperatures – acting as a ‘super catalyst’,” said Tang. “In comparison, solid nickel’s melting point is 1455°C. The same effect, to a lesser degree, is also experienced for tin metal in liquid gallium.”

  The metals were dispersed in liquid metal solvents at the atomic level. “So we have access to single atom catalysts,” said Arifur Rahim, a fellow in the University of Syndey’s School of Chemical and Biomolecular Engineering. “Single atom is the highest surface area accessibility for catalysis, which offer a remarkable advantage to the chemical industry.”

  The researchers said their approach could also be used for other chemical reactions by mixing metals using the low-temperature process. “It requires such low temperature to catalyze that we could even theoretically do it in the kitchen with the gas cooktop – but don’t try that at home,” Tang said.

  This story is adapted from material from the University of Sydney, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Molten salt takes the heat out of lithium-metal batteries

  Chibueze Amanchukwu and his group have used solvent-free inorganic molten salts to create energy-dense, safe batteries. Photo: John Zich.

  The boom in phones, laptops and other personal devices over the past few decades has been made possible by the lithium-ion (Li-ion) battery. But as climate change demands more powerful batteries for electric vehicles and grid-scale renewable storage, lithium-ion technology might not be enough.

  Lithium-metal batteries (LMBs) have theoretical capacities an order of magnitude greater than lithium-ion batteries, but a more literal boom has stymied research for decades.

  “A compounding challenge that further doomed the first wave of LMB commercialization in the late 1980s was their propensity to explode,” said Chibueze Amanchukwu, a professor in the University of Chicago’s Pritzker School of Molecular Engineering.

  Now, in a paper in Matter, Amanchukwu and colleagues report a way around this decades-old problem, by using solvent-free inorganic molten salts to create energy-dense, safe batteries, opening up new possibilities for electric vehicles and grid scale renewable energy storage.

  “We have developed a non-flammable, non-volatile system that is safe and can actually improve energy densities by 2x (compared to Li-ion),” Amanchukwu said.

  Conventional lithium-metal batteries rely on an electrolyte made by dissolving lithium salt in a solvent. Those volatile, flammable solvents – not the salt itself – caused those safety concerns.

  To combat this, researchers have tried different solvents or phases and tinkered with the salt concentration. It was always a trade-off: batteries that used solid-state inorganics for their electrolytes were safer, but batteries that used liquid electrolytes were more powerful. The result was either unsafe batteries or batteries that didn’t live up to lithium-metal batteries’ massive theoretical capabilities.

  Amanchukwu’s group took a novel approach to this challenge, questioning the conventional structure of the electrolyte itself. “The question was what’s the solvent doing there in the first place? Just remove it,” Amanchukwu said.

  So they tried making the lithium salt a liquid not by dissolving it but by melting it. This required creating a new composition of salt that melts at low temperatures. The challenge was to hit a temperature where the lithium salt melts but the lithium metal used elsewhere in the battery doesn’t.

  To give a sense of the scope of this task, pure lithium chloride melts at just over 600°C, whereas lithium metal melts at just 180°C, meaning any useful molten salt electrolyte would have to have a far lower melting point.

  Amanchukwu and his colleagues have now created a salt that melts at 45°C, resulting in a powerful battery that can operate safely at 80–100°C. “That was a sweet spot to be in the middle, to still have all the safety benefits but operate at temperatures that allow it to be liquid,” Amanchukwu said.

  His group is continuing to work on salt compositions that have even lower melting points, with the ultimate goal of developing a powerful lithium-metal battery that will operate safely at room temperature.

  “How can you get this down to 25°C or 30°C? From a research and applied point of a view, there’s lots of excitement there. We have the opportunity to create a very impactful battery that helps to solve a key global challenge – energy storage.”

  This story is adapted from material from the University of Chicago, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 09, 2023

• Materials Today -- News Soapy electrolytes could lead to better lithium-metal batteries

  The paper provides a unified theory to why this electrolyte works better and the key understanding of it came by finding that micelle-like structures form within this electrolyte like they do with soap.Bin Li, Oak Ridge National Laboratory

  When it comes to making batteries that last longer, a team including researchers at Brown University and Idaho National Laboratory believes the key might be in the way soap gets things clean.

  Take handwashing. When someone washes their hands with soap, the soap forms structures called micelles that trap and remove grease, dirt and germs when flushed with water. The soap does this because it acts as bridge between the water and what is being cleaned away, by binding them and wrapping them into those micelle structures.

  The team of researchers noticed that a similar process plays out in what has become one of the most promising substances for designing longer-lasting lithium-metal batteries — a new type of electrolyte called a localized high-concentration electrolyte. As the researchers report in a paper in Nature Materials, their new understanding of how this process works might be the missing piece to fully kicking the door open on this emerging battery technology.

  “The big picture is that we want to improve and increase the energy density for batteries, meaning how much energy they store per cycle and how many cycles the battery lasts,” said Yue Qi, a professor in Brown’s School of Engineering. “To do this, materials inside of traditional batteries need to be replaced to make long-life batteries that store more energy a reality – think batteries that can power a phone for a week or more, or electric vehicles that go for 500 miles.”

  Scientists have been actively working to transition to batteries made from lithium metal because they have a much higher energy-storage capacity than today’s lithium-ion batteries. The holdup is the electrolyte, which allows an electrical charge to pass between a battery’s two terminals, sparking the electrochemical reaction needed to convert stored chemical energy to electrical energy. The traditional electrolytes used in lithium-ion batteries, which essentially comprise a low-concentration salt dissolved in a liquid solvent, don’t do this effectively in metal-based batteries.

  Localized high-concentration electrolytes were engineered by scientists at Idaho National Laboratory and Pacific Northwest National Laboratory to address this challenge. They are made by mixing high concentrations of salt in a solvent with another liquid called a diluent, which makes the electrolyte flow better so that the power of the battery can be maintained.

  So far, in lab tests, this new type of electrolyte has shown promising results, but how and why it works has never been fully understood – putting a cap on how effective it can be and how it can be better developed. This is what the new study helps to address.

  “The paper provides a unified theory to why this electrolyte works better and the key understanding of it came by finding that micelle-like structures form within this electrolyte – like they do with soap,” said Bin Li, a senior scientist at Oak Ridge National Laboratory who worked on the study. “Here we see that the role of the soap or surfactant is played by the solvent that binds both the diluent and the salt, wrapping itself around the higher concentration salt in the center of the micelle.”

  By understanding this, the researchers were able to break down the ratios and concentrations needed to bring about the optimal reactions for the batteries. This should help solve one of the main sticking points in engineering this electrolyte: finding the proper balance for the three ingredients. In fact, this study not only provides better guidelines for making localized high-concentration electrolytes that function, but also for making ones that work even more effectively.

  Researchers at Idaho National Laboratory have already set about putting this theory into practice, finding that, so far, it holds up and helps to extend the life of lithium-metal batteries. The team is excited to see what designs for localized high-concentration electrolytes come from their work but know that significant progress is required to overcome the electrolyte-design bottleneck for high-density batteries. Right now, they are amused that the secret may have been in something as mundane and everyday as soap.

  “The concept of the micelle may be new for the electrolyte, but it’s actually very common for our daily life,” Qi said. “Now we have a theory, and we have guidelines to get interactions we want from the salt, the solvent and the diluent in the electrolyte, and what concentration they have to be at and how you mix them.”

  This story is adapted from material from Brown University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Nanosheets assemble to create protective barrier

  This scanning transmission electron microscope (STEM) image shows continuous 2D nanosheets folded at a sharp angle. Image: Emma Vargo et al./Berkeley Lab. Image courtesy of Nature.

  A new self-assembling nanosheet could radically accelerate the development of functional and sustainable nanomaterials for electronics, energy storage, health and safety, and more.

  Developed by a team led by researchers at Lawrence Berkeley National Laboratory (Berkeley Lab), the new self-assembling nanosheet could significantly extend the shelf life of consumer products. And because the new material is recyclable, it could also lead to a sustainable manufacturing approach that keeps single-use packaging and electronics out of landfills.

  The team is the first to successfully develop a multipurpose, high-performance barrier material from self-assembling nanosheets. They report their breakthrough in a paper in Nature.

  “Our work overcomes a longstanding hurdle in nanoscience – scaling up nanomaterial synthesis into useful materials for manufacturing and commercial applications,” said Ting Xu, the principal investigator who led the study. “It’s really exciting because this has been decades in the making.” Xu is a faculty senior scientist in Berkeley Lab’s Materials Sciences Division, and professor of chemistry and materials science and engineering at the University of California, Berkeley.

  One challenge of utilizing nanoscience to create functional materials is that many small pieces need to come together so that the nanomaterial can grow large enough to be useful. And while stacking nanosheets is one of the simplest ways to grow nanomaterials into a product, so-called ‘stacking defects’ – gaps between the nanosheets – are unavoidable when working with existing nanosheets or nanoplatelets.

  “If you visualize building a 3D structure from thin, flat tiles, you'll have layers up the height of the structure, but you'll also have gaps throughout each layer wherever two tiles meet,” said first author Emma Vargo, a former graduate student researcher in the Xu group and now a postdoctoral scholar in Berkeley Lab’s Materials Sciences Division. “It’s tempting to reduce the number of gaps by making the tiles bigger, but they become harder to work with.”

  The new nanosheet material overcomes the problem of stacking defects by skipping the serial stacked sheet approach altogether. Instead, the team mixed blends of materials known to self-assemble into small particles with alternating layers of the component materials, suspended in a solvent. To design the system, the researchers used complex blends of nanoparticles, small molecules and block-copolymer-based supramolecules, all of which are commercially available.

  Experiments at Oak Ridge National Laboratory’s Spallation Neutron Source helped the researchers understand the early, coarse stages of the blends’ self-assembly. As the solvent evaporates, the small particles coalesce and spontaneously organize, coarsely templating layers, and then solidify into dense nanosheets. In this way, the ordered layers form simultaneously rather than being stacked one-by-one in a serial process. The small pieces only need to move short distances to get organized and close gaps, avoiding the problems of moving larger ‘tiles’ and the inevitable gaps between them.

  From a previous study led by Xu, the researchers knew that combining nanocomposite blends containing multiple ‘building blocks’ of various sizes and chemistries, including complex polymers and nanoparticles, would not only adapt to impurities but also unlock a system’s entropy. This is the inherent disorder in mixtures of materials that Xu’s group harnessed to distribute the material’s building blocks.

  The new study builds on this earlier work. The researchers predicted that the complex blend used for the current study would have two ideal properties: in addition to having high entropy to drive the self-assembly of a stack of hundreds of nanosheets, they also expected that the new nanosheet system would be minimally affected by different surface chemistries. This, they reasoned, would allow the same blend to form a protective barrier on a variety of surfaces, such as the glass screen of an electronic device or a polyester mask.

  To test the performance of the material as a barrier coating in several different applications, the researchers enlisted the help of some of the nation’s best research facilities.

  During experiments at Argonne National Laboratory’s Advanced Photon Source, the researchers mapped out how each component of the nanosheet comes together. They also quantified the mobility of each component and the manner in which each moves around to grow a functional material.

  Based on these quantitative studies, the researchers fabricated barrier coatings by applying a dilute solution of polymers, organic small molecules and nanoparticles to various substrates – a Teflon beaker and membrane, polyester film, thick and thin silicon films, glass, and even a prototype of a microelectronic device – and then controlling the rate of film formation.

  Transmission electron microscope experiments at Berkeley Lab’s Molecular Foundry showed that by the time the solvent had evaporated, a highly ordered, layered structure of more than 200 stacked nanosheets with very low defect density had self-assembled on the substrates. The researchers also succeeded in making each nanosheet 100nm thick with few holes and gaps, which makes them particularly effective at preventing the passage of water vapor, volatile organic compounds and electrons.

  Other experiments at the Molecular Foundry showed that the material has great potential as a dielectric, an insulating ‘electron barrier’ material commonly used in capacitors for energy storage and computing applications.

  In collaboration with researchers in Berkeley Lab’s Energy Technologies Area, Xu and team demonstrated that when the material is used to coat porous Teflon membranes (a common material used to make protective face masks), it is highly effective at filtering out volatile organic compounds that can compromise indoor air quality.

  And in a final experiment in the Xu lab, the researchers showed that the material can be redissolved and recast to produce a fresh barrier coating.

  Now that they’ve successfully demonstrated how to easily synthesize a versatile functional material for various industrial applications from a single nanomaterial, the researchers plan to fine-tune the material’s recyclability and add color tunability (it currently comes in blue) to its repertoire.

  This story is adapted from material from Lawrence Berkeley National Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Wrocław University of Science and Technology The celebration of the Wrocław University of Science and Technology Day
  Join us on Wednesday, 15 November, for a celebration of Wrocław University of Science and Technology.
• Wrocław University of Science and Technology New laboratory and open lecture. Visit of Prof. Ferenc Krausz [PHOTOS]
  Wroclaw Tech hosted this year's Nobel Prize winner in physics. Prof. Ferenc Krausz opened the laboratory of the collaborative research group and gave an open lecture. He was listened to by hundreds of people gathered in the university Congress Centre

November 08, 2023

• Materials Today -- News Cellulose sheets could wrap up cancer diagnosis

  This image shows how the CNF sheets can be used to capture EVs from multiple sites in the body. Image: Takao Yasui.

  A research team in Japan, led by Akira Yokoi at Nagoya University, has used cellulose nanofiber (CNF) sheets derived from wood cellulose to capture extracellular vesicles (EVs) from fluid samples and organs during surgery.

  EVs are small structures produced by most cells, including cancerous cells, that play a crucial role in cell-to-cell communication. Extracting and analyzing EVs using this new technology has the potential to revolutionize early cancer diagnosis and open the door to personalized medicine. The researchers report their findings in a paper in Nature Communications.

  Cancer is notorious for its poor prognosis; in many cases, it goes undetected until its advanced stages, leaving patients with limited treatment options. EVs could be used to detect cancer early while also providing vital information about its status and progression. This should assist physicians in monitoring and adjusting personalized cancer treatment plans. However, researchers have been limited in previous attempts to use EVs due to the lack of an effective strategy for isolating them.

  Now, Yokoi and his colleagues have shown that CNF sheets made from wood cellulose can be used to extract EVs from fluid samples taken from ovarian cancer mice models. As the sheet has a porous nanostructure, it can absorb the EVs into its pores, which close upon drying. The researchers found that the sheets captured and preserved EVs from as little as 10µL of body fluids. In contrast, current standard methods, such as ultra-centrifugation, are more time-consuming and require much larger samples.

  “We have developed the unique cellulose nanofiber by applying paper-making and solvent-displacement technology,” Yokoi said. “The cellulose nanofibers we use are a sustainable biomass material that comes mostly from wood cell walls. These sheets have attractive properties, such as being lightweight, high strength and, most importantly, easily biodegradable.”

  Using the technique, the researchers successfully extracted and analyzed EVs, together with the microRNAs (miRNAs) contained within them, from the mice ovarian cancer models. As miRNAs differ between healthy and sick patients, they represent an ideal diagnostic marker for cancer.

  The researchers also identified distinct sets of miRNAs in EVs collected from tumor surfaces, some of which decreased after tumor removal. Tracking the presence or absence of these miRNAs could be an easy way to analyze the effectiveness of treatment and tailor it according to tumor heterogeneity, meaning the way that cancer cells can have various characteristics and properties even in a single tumor.

  The structure of the sheets is similar to that of medical gauze, so they can easily be attached and removed from organs during surgery, which the group demonstrated by testing the sheets on recently removed human organs. This test also led to a further discovery: that EVs on the surface of tumors displayed different miRNA profiles to EVs in tumor tissue.

  "Organ surfaces were a previously unanalyzed EV subpopulation, which can now be subjected to biological assessments,” Yokoi said. “CNF paper enables the obtaining of EVs from multiple sites in the body. Then, by checking the molecular profiles of these EVs, we can monitor disease progression and tailor the selection of the best drug, contributing to personalized medicine."

  Takahiro Ochiya, board member of the International Society for Extracellular Vesicles and president of the Japanese Society for Extracellular Vesicles, is enthusiastic about the potential of the sheets. “Exosome analysis using CNF sheets is an extremely novel method and is expected to have a variety of applications, including medical uses,” he said. “We expect this to be a major advance that will bring the knowledge of exosomes as medical research directly to patients.”

  This research has broad implications, opening up the analysis of EVs during surgery, an unexplored area until now. Looking ahead, the research team is committed to advancing the medical applications of EV sheets for various diseases, improving diagnostic accuracy and helping to usher in the era of personalized medicine.

  This story is adapted from material from Nagoya University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Flat route to superconducting crystals

  This shows the special cubic arrangement of atoms in the crystal, which resembles the Japanese art of kagome. Image courtesy of Joseph Checkelsky, Riccardo Comin, et al.

  Electrons move through a conducting material like commuters at the height of rush hour. The charged particles may jostle and bump against each other, but for the most part they’re unconcerned with other electrons as they hurtle forward, each with their own energy.

  But when a material’s electrons are trapped together, they can settle into the exact same energy state and start to behave as one. This collective, zombie-like state is what’s known in physics as an electronic ‘flat band’, and scientists predict that when electrons are in this state they can start to feel the quantum effects of other electrons and act in coordinated, quantum ways. Then, exotic behavior such as superconductivity and unique forms of magnetism may emerge.

  Now, researchers at Massachusetts Institute of Technology (MIT) have successfully trapped electrons in a pure crystal, marking the first time that scientists have achieved an electronic flat band in a three-dimensional (3D) material. With some chemical manipulation, the researchers also showed they could transform the crystal into a superconductor – a material that conducts electricity with zero resistance.

  The electrons’ trapped state is possible thanks to the crystal’s atomic geometry. The crystal, which the physicists synthesized, has an arrangement of atoms that resembles the woven patterns in ‘kagome’, the Japanese art of basket-weaving. In this specific geometry, the researchers found that rather than jumping between atoms, the electrons were ‘caged’ and settled into the same band of energy.

  According to the researchers, this flat-band state can be realized with virtually any combination of atoms – as long as they are arranged in this kagome-inspired 3D geometry. The results, reported in a paper in Nature, provide a new way for scientists to explore rare electronic states in 3D materials. These materials might someday be optimized for use as ultraefficient power lines, supercomputing quantum bits, and faster, smarter electronic devices.

  “Now that we know we can make a flat band from this geometry, we have a big motivation to study other structures that might have other new physics that could be a platform for new technologies,” says Joseph Checkelsky, associate professor of physics at MIT and one of the directors of the study.

  In recent years, physicists have successfully trapped electrons and confirmed their electronic flat-band state in two-dimensional (2D) materials. But scientists have found that electrons that are trapped in two dimensions can easily escape out the third, making flat-band states difficult to maintain in 2D.

  In their new study, Checkelsky and his colleagues looked to realize flat bands in 3D materials, such that electrons would be trapped in all three dimensions and any exotic electronic states could be more stably maintained. They had an idea that kagome patterns might play a role.

  In previous work, the team observed trapped electrons in a 2D lattice of atoms that resembled some kagome designs. When the atoms were arranged in a pattern of interconnected, corner-sharing triangles, electrons were confined within the hexagonal space between the triangles, rather than hopping across the lattice. But, like others, the researchers found that the electrons could escape up and out of the lattice, through the third dimension.

  This led the team to wonder whether a 3D configuration of similar lattices would work to box in the electrons. They looked for an answer in databases of material structures and came across a certain geometric configuration of atoms, classified generally as a pyrochlore – a type of mineral with a highly symmetric atomic geometry. The pychlore’s 3D structure of atoms formed a repeating pattern of cubes, the face of each cube resembling a kagome-like lattice. The researchers found that, in theory, this geometry could effectively trap electrons within each cube.

  To test this hypothesis, they synthesized a pyrochlore crystal in the lab. “It’s not dissimilar to how nature makes crystals,” Checkelsky explains. “We put certain elements together – in this case, calcium and nickel – melt them at very high temperatures, cool them down, and the atoms on their own will arrange into this crystalline, kagome-like configuration.”

  They then looked to measure the energy of individual electrons in the crystal, to see if they did indeed fall into the same flat band of energy. To do so, scientists typically carry out photoemission experiments, in which they shine a single photon of light onto a sample that kicks out a single electron. A detector can then precisely measure the energy of that individual electron.

  Scientists have used photoemission to confirm flat-band states in various 2D materials. Because of their physically flat, 2D nature, these materials are relatively straightforward to measure using standard laser light. But for 3D materials, the task is more challenging.

  “For this experiment, you typically require a very flat surface,” explains Riccardo Comin, associate professor of physics at MIT, who collaborated with Checkelsky to direct the study. “But if you look at the surface of these 3D materials, they are like the Rocky Mountains, with a very corrugated landscape. Experiments on these materials are very challenging, and that is part of the reason no-one has demonstrated that they host trapped electrons.”

  The team cleared this hurdle with angle-resolved photoemission spectroscopy (ARPES), an ultrafocused beam of light that is able to target specific locations across an uneven 3D surface and measure the individual electron energies at those locations. “It’s like landing a helicopter on very small pads, all across this rocky landscape,” Comin says.

  With ARPES, the team measured the energies of thousands of electrons across a synthesized crystal sample in about half an hour. They found that, overwhelmingly, the electrons in the crystal exhibited the exact same energy, confirming the 3D material’s flat-band state.

  To see whether they could manipulate the coordinated electrons into some exotic electronic state, the researchers synthesized the same crystal geometry, but this time with atoms of rhodium and ruthenium instead of nickel. On paper, the researchers calculated that this chemical swap should shift the electrons’ flat band to zero energy – a state that automatically leads to superconductivity.

  And indeed, they found that when they synthesized a new crystal, with a slightly different combination of elements in the same kagome-like 3D geometry, the crystal’s electrons exhibited a flat band, this time at superconducting states.

  “This presents a new paradigm to think about how to find new and interesting quantum materials,” Comin says. “We showed that, with this special ingredient of this atomic arrangement that can trap electrons, we always find these flat bands. It’s not just a lucky strike. From this point on, the challenge is to optimize to achieve the promise of flat-band materials, potentially to sustain superconductivity at higher temperatures.”

  This story is adapted from material from MIT, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 03, 2023

• Wrocław University of Science and Technology Teaching Excellence Seminars: prof. Tomi Kauppinen – Designing Online Learning
  We invite you to a meeting within a series of Teaching Excellence Seminars. The guest of the event will be prof. Tomi Kauppinen of Aalto University, who will tell us about online learning design.
• Materials Today -- News DNA assembles bipyramid nanoparticles into quasicrystals

  The fast Fourier transform of the electron microscope image of the quasicrystal, showing the 12-fold symmetry, is on the left, while the transform of the simulated crystal is on the right. Image: Mirkin Research Group, Northwestern University, and Glotzer Group, University of Michigan.

  Using DNA, the molecule that encodes life, nanoengineers have created a quasicrystal – a scientifically intriguing and technologically promising material structure – from nanoparticles. The team, led by researchers at Northwestern University, the University of Michigan and the Center for Cooperative Research in Biomaterials in San Sebastian, Spain, reports its work in a paper in Nature Materials.

  Unlike ordinary crystals, which are defined by a repeating structure, the patterns in quasicrystals don't repeat. Quasicrystals built from atoms can have exceptional properties. These include absorbing heat and light differently, exhibiting unusual electronic properties such as conducting electricity without resistance, and surfaces that are very hard or very slippery.

  Engineers studying nanoscale assembly often view nanoparticles as a kind of 'designer atom' that provide a new level of control over synthetic materials. One of the challenges is directing nanoparticles to assemble into desired structures with useful qualities, and in building this first DNA-assembled quasicrystal, the team entered a new frontier in nanomaterial design.

  "The existence of quasicrystals has been a puzzle for decades, and their discovery appropriately was awarded with a Nobel Prize," said Chad Mirkin, professor of chemistry at Northwestern University and co-corresponding author of the paper. "Although there are now several known examples, discovered in nature or through serendipitous routes, our research demystifies their formation and more importantly shows how we can harness the programmable nature of DNA to design and assemble quasicrystals deliberately."

  Mirkin's group is known for using DNA as a designer glue to engineer the formation of colloidal crystals made of nanoparticles, while the group of Luis Liz-Marzán, a professor at the Spanish Center for Cooperative Research in Biomaterials, can produce nanoparticles that might form quasicrystals under the right conditions. In this study, the team focused on nanoparticles with bipyramidal shapes – basically two pyramids stuck together at their bases.

  Liz-Marzán's group experimented with different numbers of sides as well as squashing and stretching the shapes. Wenjie Zhou and Haixin Lin, doctoral students in chemistry at Northwestern at the time of the work, used DNA strands encoded to recognize one another to program these nanoparticles to assemble into a quasicrystal.

  Independently, the group of Sharon Glotzer, chair of chemical engineering at the University of Michigan, had been simulating bipyramids with different numbers of sides. Yein Lim and Sangmin Lee, doctoral students in chemical engineering at the University of Michigan, found that decahedra – 10-sided pentagonal bipyramids – would form a quasicrystal under certain conditions, and with the right relative dimensions.

  In 2009, Glotzer's team predicted the first layered nanoparticle quasicrystal, made not from bipyramids but from tetrahedra—single pyramids with four triangular sides. Because five tetrahedra can nearly make a type of decahedron, she says that the decahedron was a savvy choice for making a quasicrystal.

  "In our original quasicrystal simulation, the tetrahedra arranged into decahedra with very small gaps between the tetrahedra," said Glotzer, a co-corresponding author of the paper. “Here, those gaps would be filled by DNA, so it made sense that decahedra might make quasicrystals, too.”

  Through a combination of theory and experiment, the three research groups were able to make the decahedron particles into a quasicrystal, which they confirmed with electron microscope imaging at Northwestern and X-ray scattering at Argonne National Laboratory.

  The structure of the quasicrystal resembles an array of rosettes in concentric circles, the 10-sided shapes creating a 12-fold symmetry in two-dimensional layers that stack periodically. This stacked structure, also seen with quasicrystals made from tetrahedra, is called an axial quasicrystal. But unlike most axial quasicrystals, the tiling pattern of the new quasicrystal's layers do not repeat identically from one layer to the next. Instead, a significant percentage of tiles are different, in a random way – and this small amount of disorder adds stability.

  "Through the successful engineering of colloidal quasicrystals, we have achieved a significant milestone in the realm of nanoscience," said Liz-Marzán, co-corresponding author of the paper. "Our work not only sheds light on the design and creation of intricate nanoscale structures but also opens a world of possibilities for advanced materials and innovative nanotechnology applications."

  This story is adapted from material from the University of Michigan, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New amorphous material produces some strong string

  An artists impression of testing the tensile strength of amorphous silicon carbide nanostrings. Image: Science Brush.

  Researchers at Delft University of Technology in the Netherlands, led by assistant professor Richard Norte, have unveiled a remarkable new material with potential to impact the world of material science. Termed amorphous silicon carbide (a-SiC), this novel material possesses several useful mechanical properties, including exceptional strength.

  The range of potential applications is vast. From ultra-sensitive microchip sensors and advanced solar cells, to pioneering space exploration and DNA sequencing technologies. The advantages of this material's strength combined with its scalability make it exceptionally promising. The researchers describe the new amorphous material in a paper in Advanced Materials.

  “To better understand the crucial characteristic of ‘amorphous’, think of most materials as being made up of atoms arranged in a regular pattern, like an intricately built Lego tower,” explains Norte. “These are termed as ‘crystalline’ materials, like for example, a diamond. It has carbon atoms perfectly aligned, contributing to its famed hardness.”

  Amorphous materials, on the other hand, are akin to a randomly piled set of Legos, where atoms lack consistent arrangement. But contrary to expectations, this randomization doesn't result in fragility. In fact, amorphous silicon carbide is a testament to the strength that can emerge from such randomness.

  The tensile strength of this new material is 10 GigaPascal (GPa). “To grasp what this means, imagine trying to stretch a piece of duct tape until it breaks,” says Norte. “Now if you’d want to simulate the tensile stress equivalent to 10GPa, you'd need to hang about ten medium-sized cars end-to-end off that strip before it breaks.”

  The researchers adopted an innovative method to test this material's tensile strength. Instead of using traditional methods, which might introduce inaccuracies from the way the material is anchored, they turned to microchip technology. By growing tiny strings of amorphous silicon carbide on a silicon substrate and suspending them, they leveraged the geometry of the nanostrings to induce high tensile forces.

  By fabricating many such structures with increasing tensile forces, they meticulously observed the point of breakage. This microchip-based approach not only ensured unprecedented precision but also paves the way for future material testing.

  “Nanostrings are fundamental building blocks, the very foundation that can be used to construct more intricate suspended structures,” Norte says. “Demonstrating high yield strength in a nanostring translates to showcasing strength in its most elemental form.”

  What also sets this material apart is its scalability. Graphene, a single layer of carbon atoms, is known for its impressive strength but is challenging to produce in large quantities. Diamonds, though immensely strong, are either rare in nature or costly to synthesize. In contrast, amorphous silicon carbide can be produced at wafer scales, leading to large sheets of this incredibly robust material.

  “With amorphous silicon carbide's emergence, we're poised at the threshold of microchip research brimming with technological possibilities,” concludes Norte.

  This story is adapted from material from Delft University of Technology, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

November 02, 2023

• Materials Today -- News ‘Plug-and-play’ nanoparticles wear coat of many proteins

  Live cell fluorescent visualization of biological molecules binding to the surface of genetically modified cell membranes, which are coated onto the modular nanoparticles. Image: Zhang lab/UC San Diego Jacobs School of Engineering.

  Engineers at the University of California (UC) San Diego have developed modular nanoparticles that can be easily customized to target different biological entities, such as tumors, viruses or toxins. The surfaces of the nanoparticles can be engineered to host any biological molecules of choice, making it possible to tailor the nanoparticles for a wide array of applications, ranging from targeted drug delivery to neutralizing biological agents.

  The beauty of this technology lies in its simplicity and efficiency. Instead of crafting entirely new nanoparticles for each specific application, researchers can now employ a modular nanoparticle base and then conveniently attach proteins targeting a desired biological entity. In the past, creating distinct nanoparticles for different biological targets required going through a different synthetic process from start to finish each time. But with this new technique, the same modular nanoparticle base can be easily modified to create a whole set of specialized nanoparticles.

  “This is a plug-and-play platform technology that allows for rapid modification of a functional biological nanoparticle,” said Liangfang Zhang, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering. Zhang and his team report their work in a paper in Nature Nanotechnology.

  The modular nanoparticles consist of biodegradable polymer cores coated with genetically modified cell membranes. The key to their modular design is a pair of synthetic proteins, known as SpyCatcher and SpyTag, that are specifically designed to spontaneously – and exclusively – bind with each other. This pair is commonly used in biological research to combine various proteins. Now, Zhang and his team have harnessed the pair to create a system for attaching proteins of interest to a nanoparticle surface with ease.

  In this system, SpyCatcher is embedded on the nanoparticle surface, while SpyTag is chemically linked to a protein of interest, such as one targeting tumors or viruses. When SpyTag-linked proteins come into contact with SpyCatcher-decorated nanoparticles, they readily bind to each other, allowing proteins of interest to be effortlessly attached to the nanoparticle surface.

  For example, to target tumors, SpyTag can be linked to a protein designed to seek out tumor cells, and that SpyTag-linked protein is then attached to the nanoparticle. If the target shifts to a specific virus, the process is similarly straightforward: simply link SpyTag to a protein targeting the virus and attach it to the nanoparticle surface.

  “It’s a very simple, streamlined and straightforward approach to functionalizing nanoparticles for any biological application,” said Zhang.

  To create the modular nanoparticles, the researchers first genetically engineered human embryonic kidney (HEK) 293 cells – a commonly used cell line in biological research – to express SpyCatcher proteins on their surface. The cell membranes were then isolated, broken into smaller pieces and coated onto biodegradable polymer nanoparticles.

  These nanoparticles were subsequently mixed with SpyTag-linked proteins. In this study, the researchers used two different proteins: one targeting the epidermal growth factor receptor (EGFR) and the other targeting human epidermal growth factor receptor 2 (HER2), both of which are prevalent on the surface of various cancer cells.

  As a proof of concept, the researchers tested these nanoparticles in mice with ovarian tumors. The nanoparticles were loaded with docetaxel, a chemotherapy medication, and administered to mice via intravenous injection every three days for a total of four injections. Treatment with these nanoparticles suppressed tumor growth while improving survival rate. Treated mice had median survival of 63 to 71 days, while the median survival of untreated mice was 24 to 29 days.

  The researchers are now looking to further improve the modular nanoparticle platform for targeted drug delivery.

  In addition to cancer treatment, Zhang is excited about other potential applications of this technology. “Because we have a modular nanoparticle base, we can easily attach a neutralizing agent on the surface to neutralize viruses and biological toxins,” he said. “There is also potential for creating vaccines by attaching an antigen on the nanoparticle surface using this modular platform. This opens the door to a variety of new therapeutic approaches.”

  This story is adapted from material from the University of California, San Diego, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Toughening up 3D-printed metals without heating and beating

  This conceptual illustration shows how the research teams processing strategies can be used to manipulate the structure of metals spatially during laser powder bed fusion processing. Image: Matteo Seita.

  Researchers have developed a new method for 3D printing metal that could help to reduce costs and make more efficient use of resources.

  The method, developed by a team led by researchers at the University of Cambridge in the UK, allows structural modifications to be ‘programed’ into metal alloys during 3D printing. This means their properties can be fine-tuned without the ‘heating and beating’ process that’s been in use for thousands of years.

  The new 3D-printing method combines the best qualities of both worlds: the complex shapes that 3D printing makes possible, and the ability offered by traditional methods to engineer the structure and properties of metals. The team reports its work in a paper in Nature Communications.

  The process of 3D printing has several advantages over other manufacturing methods. For example, it’s far easier to produce intricate shapes using 3D printing, and it uses far less material than traditional metal manufacturing methods, making it a more efficient process. However, it also has significant drawbacks.

  “There’s a lot of promise around 3D printing, but it’s still not in wide use in industry, mostly because of high production costs,” said Matteo Seita from Cambridge’s Department of Engineering, who led the research. “One of the main drivers of these costs is the amount of tweaking that materials need after production.”

  Since the Bronze Age, metal parts have been made through a process of heating and beating. This approach, where the material is hardened with a hammer and softened by fire, allows the maker to form the metal into the desired shape and at the same time impart physical properties such as flexibility or strength.

  “The reason why heating and beating is so effective is because it changes the internal structure of the material, allowing control over its properties,” said Seita. “That’s why it’s still in use after thousands of years.”

  One of the major downsides of current 3D-printing techniques is an inability to control the internal structure in the same way, which is why so much post-production alteration is required. “We’re trying to come up with ways to restore some of that structural engineering capability without the need for heating and beating, which would in turn help reduce costs,” said Seita. “If you can control the properties you want in metals, you can leverage the greener aspects of 3D printing.”

  Working with colleagues in Singapore, Switzerland, Finland and Australia, Seita developed a new ‘recipe’ for 3D-printed metal that confers a high degree of control over the internal structure of the material as it is being melted by a laser.

  By controlling the way the material solidifies after melting, and the amount of heat that is generated during the process, the researchers can program the properties of the end material. Normally, metals are designed to be strong and tough, so that they are safe to use in structural applications; 3D-printed metals are inherently strong, but also brittle.

  The strategy the researchers developed gives full control over both strength and toughness, by triggering a controlled reconfiguration of the microstructure when the 3D-printed metal part is placed in a furnace at relatively low temperatures. Their method uses conventional laser-based 3D printing technologies, but with a small tweak to the process.

  “We found that the laser can be used as a ‘microscopic hammer’ to harden the metal during 3D printing,” said Seita. “However, melting the metal a second time with the same laser relaxes the metal’s structure, allowing the structural reconfiguration to take place when the part is placed in the furnace.”

  Their 3D-printed steel, which was designed theoretically and validated experimentally, was made with alternating regions of strong and tough material, making its performance comparable to steel that’s been made through heating and beating.

  “We think this method could help reduce the costs of metal 3D printing, which could in turn improve the sustainability of the metal manufacturing industry,” said Seita. “In the near future, we also hope to be able to bypass the low-temperature treatment in the furnace, further reducing the number of steps required before using 3D printed parts in engineering applications.”

  This story is adapted from material from the University of Cambridge, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 26, 2023

• Wrocław University of Science and Technology This year's Nobel laureate will come to Wroclaw Tech
  Prof Ferenc Krausz - a world-renowned physicist and winner of this year's Nobel Prize in physics - will come to Wroclaw Tech. Scientist will open new research center at our university and give an open lecture.

October 25, 2023

• Materials Today -- News Improved perovskite photovoltaic cells using anti-reflective layer

  Researchers from the Fraunhofer Institute for Solar Energy ISE and the University of Warsaw have demonstrated perovskite photovoltaic cells with significantly improved optoelectronic properties. These cells have a nanoimprinted structured anti-reflective layer with a manufactured honeycomb texture to enhance its performance that could help commercialization of the material in photovoltaic panels on a wider scale.

   

  Perovskite-based solar cells are seen as successors to the commonly used silicon cells because of their easy and cost-effective production process, as well as excellent performance, with their panel efficiency and installed capacity photovoltaics being vastly improved. In addition, silicon cells are now approaching their limits of physical efficiency. New solutions are therefore needed that enhance cell efficiency while allowing cheaper and more environmentally friendly production. Perovskite-based cells achieve both criteria, providing efficiency of more than 26%.

   

  A problem lies in the integration of perovskite cells with silicon cells while simultaneously reducing losses from reflection and parasitic absorption. To reduce such losses, silicon cells usually have microscopic pyramid patterns etched on their surface by highly corrosive chemical agents, which lessens the reflection of the entire device and increases its current. As perovskites are sensitive to a range of chemical substances, less effective planar anti-reflective coatings tend to be applied.

   

  Bringing down optical losses in new types of cells is also a major challenge in terms of their broader implementation. However, as reported in Advanced Materials and Interfaces [Krajewski et al. Adv. Mater. Interfaces (2023) DOI: 10.1002/admi.202300134], here a nanoimprinting method was used to produce an efficient anti-reflective structure with honeycomb-like symmetry that sits on top of the perovskite solar cell.

   

  The method allows the production of nanometer-scale structures on very large surfaces, exceeding 100 cm². As researcher Maciej Krajewski said “This approach guarantees scalability in the production process of large-surface devices, which is crucial in the context of the urgent need for energy transformation toward renewable energy sources.”

   

  The use of the direct nanoimprinting method makes it possible to produce the complete device in just one technological process, which is key for reducing overall device costs. As well as enhancing efficiency, the application procedure for this layer doesn’t harm the perovskite, which isn’t always the case for anti-reflective structures.

   

  As the process is compatible with a tandem configuration for silicon and perovskite cells, there are many possible opportunities for the application. For instance, it has the potential to directly transfer the procedure to emerging photovoltaic architectures, perhaps bringing even more improvements in efficiency.

  This approach guarantees scalability in the production process of large-surface devices, which is crucial in the context of the urgent need for energy transformation toward renewable energy sources.Maciej Krajewski

• Wrocław University of Science and Technology It's time for T.I.M.E.
  Representatives of 48 universities from 21 countries are taking part in the T.I.M.E. General Assembly conference, which has begun at Wroclaw Tech. The three-day event will feature workshops, talks and discussions on internationalisation.

October 20, 2023

• Materials Today -- News Biodegradable piezoelectric wound dressing boosts healing

  Application of biodegradable piezoelectric PLLA nanofibers on a wound in combination with external ultrasound to produce controllable surface charge for wound healing and prevention of bacterial infection. The biocompatible scaffold facilitates tissue ingrowth for skin healing and prevents bacterial infections. Reproduced with permission from: Das et al., Biomaterials 301 (2023) 122270.

  Skin cells grown in the nanofiber scaffold. Courtesy of Thanh D. Nguyen.

  A novel wound dressing scaffold material exploits the piezoelectric effect to stimulate healing and protect against bacterial infection [Das et al., Biomaterials 301 (2023) 122270, http://doi.org/10.1016/j.biomaterials.2023.122270].

  Large or chronic skin wounds can be difficult to treat, requiring dressings that provide a physical barrier, prevent bacterial infection, absorb fluids while keeping tissue moist, and support the regrowth of skin. Conventional bandages and more recent biomaterials such as polyurethane and hydrogel membranes struggle to meet all these requirements.

  Instead, a team from the University of Connecticut, Boston University, and New York University led by Thanh D. Nguyen turned to nanofibrous materials, which have a large surface-to-volume ratio, absorb fluids, are permeable to moisture, and flexible enough to conform to the skin and stretch with the movement of muscles. They identified piezoelectric nanofibers made from poly-L-lactic acid (PLLA) as a suitable skin-wound scaffold material.

  “Our lab had developed a nanofiber PLLA scaffold, which had strong piezoelectric properties. We wanted to see if [this] piezoelectric PLLA membrane could be used to heal skin wounds and prevent infection when activated by ultrasound,” explain first author Ritopa Das and Nguyen.

  The biocompatible, biodegradable PLLA scaffold is activated by external ultrasound stimulation, which produces surface charges to either promote skin regeneration (positive) or suppress bacterial growth (negative). Both in vitro and in vivo studies in mice reveal that ultrasound-activated piezoelectric PLLA scaffolds encourage the attachment and proliferation of skin cells, promote new skin formation including the hair follicles and blood vessels, and exhibit an antibacterial effect against common strains including S. aureus and P. aeruginosa.

  “Our… piezoelectric PLLA scaffolds under ultrasound activation enhance gene expression and cell proliferation in fibroblasts and epithelial cells in vitro, produce reactive oxygen species that can kill bacteria, and accelerate wound closure as well as promote healthy skin formation in mice in vivo,” point out Das and Nguyen.

  Not only does the ultrasound-activated piezoelectric PLLA scaffold improve the rate of wound healing, but the nanofibers also degrade naturally inside the body as the skin heals, eliminating the need for replacement or removal, which can be invasive and painful for patients.

  “The PLLA scaffold is integrated with the skin and biodegrades to facilitate tissue ingrowth, avoiding the need of frequent dressing replacements, which are damaging to the healed skin and prone to infection,” they add.

  The researchers now plan to test the scaffold material in larger animal models and improve the anti-inflammatory/bacterial effect with other biodegradable components.

• Materials Today -- News Scalable upcycling of polyesters could reduce plastic waste

  A team of scientists from Tokyo Metropolitan University have devised a new chemical process that can upcycle polyesters, such as the polyethylene terephthalate (PET) in plastic water bottles, to morpholine amide. The reaction process is both high yield and waste-free, does not need chemicals, and is also easily scalable, helping to break the often expensive closed-loop recycling of plastic waste.

   

  Recycling is key to fighting the mounting problem of plastic waste, but can be expensive since the recycling of polyesters tends to need power to make the required chemical reactions sufficiently hot, or strongly alkaline conditions that generate chemical waste. By the end of this process there are intermediate compounds that are used to make the same products they came from. This is often a wasteful process as well as not being very economically viable.

   

  However, upcycling can break this closed loop and produce compounds from plastic waste that are more valuable and useful. Such an “open-loop” scheme is a crucial element of way to achieve the transition to a greener society. As detailed in the journal ACS Organic & Inorganic Au [Ogiwara, Y. and Nomura, K. ACS Org. Inorg. Au. (2023) DOI: 10.1021/acsorginorgau.3c00037], here a virtually waste-free approach to converting polyesters into morpholine amide, which is a useful building block that can then be converted into a variety of valuable chemical compounds, was developed.

   

  Morpholine and a small amount of a titanium-based catalyst were used to turn polyesters into morpholine amides. In addition to being converted into intermediate compounds for making more polyester, they can also be easily reacted to produce ketones, aldehydes and amines, which are important families of chemicals for making many other compounds.

   

  This new process does not need expensive reagents or harsh conditions, and is mostly free from chemical waste, offering an extremely high yield, with unreacted solvent being easily collected, and simple filtration working to separate the product. It is crucial that the main reaction is carried out at normal pressure, which means that no special reaction vessels or devices are used, making the reaction easily scalable.

   

  The researchers, Yohei Ogiwara and Kotohiro Nomura, demonstrated the process by taking 50g of a PET material from a PET beverage bottle and reacting it with morpholine, getting more than 70 grams of morpholine amide, a yield of 90%. With global plastic waste being an increasing problem around the world, such innovative approaches will be needed to process and redeploy plastics.

October 19, 2023

• Materials Today -- News Bioinspired electronic eye offers simple solution

  Bio-inspired electronic eye based on an all-solution-processed transparent retina. (Top left) Schematic illustration of the electronic eye based on a fully transparent retina. Inset shows the transparent retina attached on an eyeball model. (Top right) Optical transmission spectra of the transparent retina. (Bottom left) Schematic illustration of transparent retina perceiving UV light from all directions. (Bottom right) Reconstructed images of letter E and · captured by an electronic eye prototype. The numbers 025 represent plane space location of the sensing units. The color bar represents the greyscale values.

  The simple and compact hemispherical eyes of living organisms offer inspiration for next-generation imaging systems. But fabricating artificial hemispherical electronic eyes is challenging using conventional processing methods. Now researchers report a straightforward solution-based route for fabricating bio-mimicking electronic eyes [Gao et al., Materials Today (2023), https://doi.org/10.1016/j.mattod.2023.06.004].

  “Currently, extreme processing routes for electronic eye devices, requiring high temperature and vacuum conditions, significantly limit applications,” explains Zhan Gao of City University of Hong Kong. “We wanted to come up with a low-cost, facile process.”

  Together with coworkers at Hong Kong Centre for Cerebro-Cardiovascular Health Engineering and The Chinese University of Hong Kong, the team led by Hua Zhang, Zhiyuan Zeng, and Xinge Yu developed an electronic eye system featuring a fully transparent artificial retina fabricated using a room temperature solution-based method.

  “By our all-solution process, we can fabricate electronic eye systems with higher throughput and at low cost,” points out Gao.

  The artificial retina is made up of a 16 x 16 light-sensing ZnO nanoparticle/MoS₂ nanosheet composite photodetector array served by Ag nanowire conductive interconnects and electrodes embedded in a transparent PVA film on a PMMA substrate. The hemispherical PMMA dome mimics the shape of a natural eyeball, while the photodetector array acts as the retina. The device shows a reliable UV response and high transparency across the visible and IR ranges, enabling the sensing of light from all angles.

  Eyes in nature, meanwhile, can be concave or convex: the human eye, for example, relies on a light-sensitive concave surface with a retina for high resolution image formation while the compound eyes of spiders are convex in structure, enabling wide fields of view and high motion sensitivity. Thanks to the combination of solution processing and fully flexible transparent materials used, the researchers fabricated both concave and convex hemispherical electronic eye prototypes in a single configuration. The combination of concave and convex devices enables double-sided imaging.

  “Compared with other approaches for electronic eyes, our approach shows greater advantages in terms of fabrication cost and efficiency,” says Gao. “[Our approach] could make bio-inspired electronic eyes with higher system-level efficiency practical.”

  The simple, low-cost fabrication process is compatible with a wide range of materials and the team now plan to develop stretchable electronic eye systems based on soft materials. These bio-inspired devices could also be integrated with energy harvesting systems such as solar cells to create self-powered, miniaturized, portable electronic eyes.

• Materials Today -- News Tiny piezoelectric strands create electricity from molecular motion

  The electricity-generating mechanism of the molecular thermal motion harvester. Image: Yucheng Luan and Wei Li.

  Wave energy technology is a proven source of power generation, but power is also inherent in every molecule of liquid on earth, even when the liquid is at rest. At the molecular scale, atoms and ions are always moving. If this nanoscale movement can be harvested, it could be a big source of energy.

  “There are vast amounts of air and liquid on the earth, and their successful harvesting could produce a gigantic amount of energy for society,” said Yucheng Luan from East Eight Energy Co. in China.

  Together with collaborators, Luan has tested a molecular energy harvesting device that can capture the energy from the natural motion of molecules in a liquid. This work, reported in a paper in APL Materials, showed that molecular motion can be used to generate a stable electric current.

  To create the device, Luan and his collaborators submerged nanoarrays of a piezoelectric material in liquid, allowing the movement of the liquid to move the piezoelectric strands like seaweed waving in the ocean. In this case, however, the movement is on the invisible, molecular scale, and the strands are made of zinc oxide. The zinc oxide material was chosen for its piezoelectric properties, which means that when it waves, bends or deforms under motion, it generates an electric potential.

  “As a well-studied piezoelectric material, zinc oxide can be easily synthesized into various nanostructures, including nanowhiskers,” Luan said. “A nanowhisker is a neat and orderly structure of many nanowires, similar to the bristles on a toothbrush.”

  These energy harvesters could be used to power nanotechnologies like implantable medical devices, or they could be scaled up to full-size generators for kilowatt-scale energy production. One key design feature of the device is that it doesn’t rely on any external forces, enhancing its potential as a game-changing clean energy source.

  “Molecular thermal motion harvester devices do not need any external stimulation, which is a big advantage compared with other energy harvesters,” Luan explained. “At present, electrical energy is mainly obtained by external energy, such as wind energy, hydroelectric energy, solar energy and others. This work opens up the possibility of generating electrical energy through the molecular thermal motion of liquids, from the internal energy of the physical system that is essentially different from ordinary mechanical motion.”

  The researchers are already working on the next phase of their design to improve the energy density of the device by testing different liquids and different high-performing piezoelectric materials. They are also exploring new device architectures and looking at enlarging the device.

  “We believe this novel kind of system will become an indispensable way for human beings to obtain electrical energy in the near future,” said Luan.

  This story is adapted from material from the American Institute of Physics, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 18, 2023

• Materials Today -- News Photonic crystals can bend light like gravity

  Images of a distorted photonic crystal and a normal photonic crystal. Image: K. Kitamura et.al.

  A collaborative group of researchers has shown they can manipulate the behavior of light as if it were under the influence of gravity. Their findings, reported in a paper in Physical Review A, have far-reaching implications for the world of optics and materials science, and bear significance for the development of 6G communications.

  Albert Einstein's theory of relativity has long established that the trajectory of electromagnetic waves – including light and terahertz electromagnetic waves – can be deflected by gravitational fields.

  Recently, scientists have theoretically predicted that the effects of gravity can be replicated (so-called pseudogravity) by deforming crystals in the lower normalized energy (or frequency) region. "We set out to explore whether lattice distortion in photonic crystals can produce pseudogravity effects," says Kyoko Kitamura from Tohoku University's Graduate School of Engineering in Japan.

  Photonic crystals possess unique properties that allow scientists to manipulate and control the behavior of light, serving as 'traffic controllers' for light within crystals. They are constructed by periodically arranging two or more different materials with varying abilities to interact with and slow down light in a regular, repeating pattern. Furthermore, pseudogravity effects due to adiabatic changes have been observed in photonic crystals.

  In this study, Kitamura and her colleagues modified photonic crystals by introducing lattice distortions: gradual deformations of the regular spacing of elements, which disrupted the grid-like pattern of the photonic crystals. This manipulated the photonic band structure of the crystals, resulting in a curved beam trajectory in-medium – just like a light-ray passing by a massive celestial body such as a black hole.

  Specifically, the researchers employed a silicon-distorted photonic crystal with a primal lattice constant of 200µm and terahertz waves. In experiments, they successfully demonstrated the deflection of these waves.

  "Much like gravity bends the trajectory of objects, we came up with a means to bend light within certain materials," explains Kitamura.

  "Such in-plane beam steering within the terahertz range could be harnessed in 6G communication," said Masayuki Fujita, an associate professor from Osaka University in Japan. “Academically, the findings show that photonic crystals could harness gravitational effects, opening new pathways within the field of graviton physics.”

  This story is adapted from material from Tohoku University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Electron beam radiation could enhance materials in electronic devices

  Scientists at the University of Minnesota Twin Cities have demonstrated that the electron beam radiation previously believed to degrade crystals can in fact repair cracks in such nanostructures. It is hoped that the breakthrough could offer a new approach to developing more perfect crystal nanostructures, a process critical to improving the efficiency and cost-effectiveness of materials common in nearly all electronic devices used today.

   

  Researchers have long thought that when the crystals were put under electron beam radiation they would degrade, but here they found that when a crystal of titanium dioxide (TiO₂) was irradiated with an electron beam, the naturally occurring narrow cracks filled in and managed to heal themselves. The discovery was found by accident when the team were using scanning transmission electron microscopy (STEM) to examine the structural and plasmonic properties of these nanoscale cracks and the cracks kept closing on them.

   

  As reported in the journal Nature Communications [Guo et al. Nat. Commun. (2023) DOI: 10.1038/s41467-023-41781-x], instead of electron beam radiation damaging and degrading crystalline materials, they observed the opposite, a constructive aspect of the radiation. In the self-healing process, several atoms of the crystal combined in tandem with increasing electron doses and came together in the middle to form a kind of bridge that worked to fill the crack.

   

  This is the first time that the electron beams have been employed in a constructive way to engineer novel nanostructures on an atom-by-atom basis. Regardless of whether it is atomically sharp cracks or another type of defect in a crystal, it seems to be inherent in the materials that were grown. The use of electron beam exposure during the growth of crystalline thin film for a variety of technologically important materials could therefore help to significantly improve the film quality.

   

  As lead researcher Andre Mkhoyan told Materials Today, “This discovery will force researchers to re-evaluate and re-examine their view about the effects of electron beam radiation. There is a new opportunity to use constructive force of electron beam radiation.”

   

  The team now plan to find further ways to engineer the process and to introduce new factors, such as altering the conditions of the electron beam or the temperature of crystal to identify how to improve or speed up the process. In addition, they are hoping to investigate different parameters of the electron beam and crystals to make this radiolysis-based process more efficient and practical.

  This discovery will force researchers to re-evaluate and re-examine their view about the effects of electron beam radiation. There is a new opportunity to use constructive force of electron beam radiation.Andre Mkhoyan

  In the self-healing process, several atoms of the crystal combine to form a bridge to fill the crack

October 17, 2023

• Wrocław University of Science and Technology „The Anthropocene: from boundaries to bonds. Interdisciplinary crossovers in knowledge development”
  Academia Europaea Wrocław Knowledge Centre and Olga Tokarczuk's Ex-centrum Academic Research Centre invite you to participate in the conference „The Anthropocene: from boundaries to bonds. Interdisciplinary crossovers in knowledge development”.
• Materials Today -- News New technology can measure strain during 3D printing

  The OpeN-AM experimental platform, installed at the VULCAN instrument at ORNLs Spallation Neutron Source, features a robotic arm that prints layers of molten metal to create complex shapes. Image: Jill Hemman, ORNL/U.S. Dept. Of Energy.

  By using neutrons to visualize the additive manufacturing process at the atomic level, scientists have shown they can measure strain in a material as it evolves and track how atoms move in response to stress.

  “The automotive, aerospace, clean energy and tool-and-die industries – any industry that needs complex and high-performance parts – could use additive manufacturing,” said Alex Plotkowski, materials scientist in the Materials Science and Technology Division of Oak Ridge National Laboratory (ORNL) and lead scientist of the study. Plotkowski and his colleagues report their findings in a paper in Nature Communications.

  ORNL scientists have developed OpeN-AM, a 3D printing platform that can measure evolving residual stress during manufacturing using the VULCAN beamline at ORNL’s Spallation Neutron Source (SNS), a US Department of Energy (DOE) Office of Science user facility. When combined with infrared imaging and computer modeling, this system provides unprecedented insight into material behavior during manufacturing.

  Over the course of two years, the scientists conceived and produced the OpeN-Am platform for measuring strain in a material as it evolves, which determines how stresses will be distributed. They then used the OpeN-Am platform to measure how the atoms in low-temperature transformation (LTT) steel move in response to stress, whether induced by temperature or load.

  Residual stresses are stresses that remain even after a load or the cause of the stress is removed; they can deform a material or, worse, cause it to fail prematurely. Such stresses are a major challenge for fabricating accurate components with desirable properties and performance.

  “Manufacturers will be able to tailor residual stress in their components, increasing their strength, making them lighter and in more complex shapes,” Plotkowski said. “The technology can be applied to anything you want to manufacture.

  “We have successfully shown that there is a way to do that. We are demonstrating we understand connections in one case to anticipate other cases.”

  The scientists recently earned a 2023 R&D 100 Award for this technology.

  In the study, they used a custom wire-arc additive manufacturing platform to perform what’s called operando neutron diffraction of an LTT metal at SNS. Using SNS’s VULCAN beamline, they processed the steel and recorded data at various stages during manufacturing and after cooling to room temperature. They then combined the diffraction data with infrared imaging to confirm their results.

  The system was designed and built at the Manufacturing Demonstration Facility (MDF), a DOE Advanced Materials and Manufacturing Technologies Office user consortium, where a replicate system was also constructed to plan and test experiments before executing at the beamline.

  SNS operates a linear particle accelerator that produces beams of neutrons to study and analyze materials at the atomic scale. The OpeN-Am platform allows scientists to peer inside a material as it’s being produced, literally observing the mechanisms at work in real time.

  The LTT steel was melted and deposited in layers. As the metal solidified and cooled, its structure transformed, in what is called a phase transformation. When that happens, atoms rearrange and take up different space, and the material behaves differently.

  Normally, transformations that happen at high temperatures are hard to understand when looking at a material only after processing. But by observing the LTT steel during processing, the scientists showed that they can understand and manipulate the phase transformation.

  “We want to understand what these stresses are, explain how they got there and figure out how to control them,” Plotkowski said.

  “These results provide a new pathway to design desirable residual stress states and property distributions within additive manufacturing components by using process controls to improve nonuniform spatial and temporal variations of thermal gradients around key phase transformation temperatures,” the authors write in the paper.

  Plotkowski hopes scientists from around the world come to ORNL to do similar experiments on metals they would like to use in manufacturing.

  This story is adapted from material from ORNL, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News DUCKY polymers take a quack at processing crude oil

  A sample of a DUCKY polymer membrane. Photo: Candler Hobbs, Georgia Institute of Technology.

  A new kind of polymer membrane created by researchers at Georgia Institute of Technology (Georgia Tech) could reshape how refineries process crude oil, dramatically reducing the energy and water required while extracting even more useful materials.

  The so-called DUCKY polymers are reported in a paper in Nature Materials. And they’re just the beginning for the team of Georgia Tech chemists, chemical engineers and materials scientists. They have also created artificial intelligence (AI) tools to predict the performance of these kinds of polymer membranes, which could accelerate development of new ones.

  The implications are stark: the initial separation of crude oil components is responsible for roughly 1% of energy used across the globe. What’s more, the membrane separation technology the researchers are developing could have several uses, from biofuels and biodegradable plastics to pulp and paper products.

  “We're establishing concepts here that we can then use with different molecules or polymers, but we apply them to crude oil because that's the most challenging target right now,” said M.G. Finn, professor in the School of Chemistry and Biochemistry.

  Crude oil in its raw state includes thousands of compounds that have to be processed and refined to produce useful materials – gas and other fuels, as well as plastics, textiles, food additives, medical products and more. Squeezing out the valuable stuff involves dozens of steps, but it starts with distillation, a water- and energy-intensive process.

  Researchers have been trying to develop membranes to do that work instead, filtering out the desirable molecules and skipping all the boiling and cooling.

  “Crude oil is an enormously important feedstock for almost all aspects of life, and most people don't think about how it's processed,” said Ryan Lively, professor in the School of Chemical and Biomolecular Engineering. “These distillation systems are massive water consumers, and the membranes simply are not. They're not using heat or combustion. They just use electricity. You could ostensibly run it off of a wind turbine, if you wanted. It’s just a fundamentally different way of doing a separation.”

  What makes the team’s new membrane formula so powerful is a new family of polymers. The researchers used building blocks called spirocyclic monomers that assemble together in chains with lots of 90° turns, forming a kinky material that doesn’t compress easily and contains pores that selectively bind and permit desirable molecules to pass through. The polymers are not rigid, which means they’re easier to make in large quantities. They also have a well-controlled flexibility or mobility that allows pores of the right filtering structure to come and go over time.

  The DUCKY polymers are created through a chemical reaction that’s easy to produce at a scale that would be useful for industrial purposes. It’s a member of a Nobel-Prize-winning family of reactions called click chemistry, and that’s what gives the polymers their name. The reaction is called copper-catalyzed azide-alkyne cycloaddition – abbreviated CuAAC and pronounced ‘quack’. Thus: DUCKY polymers.

  In isolation, the three key characteristics of the polymer membranes aren’t new; it’s their unique combination that makes them a novelty and effective, Finn said.

  The research team included scientists at ExxonMobil, who discovered just how effective the membranes could be. The company’s scientists took the crudest of the crude oil components – the sludge left at the bottom after the distillation process – and pushed it through one of the membranes. The process extracted even more valuable materials.

  “That's actually the business case for a lot of the people who process crude oils,” Lively said. “They want to know what they can do that’s new. Can a membrane make something new that the distillation column can't? Of course, our secret motivation is to reduce energy, carbon and water footprints, but if we can help them make new products at the same time, that's a win-win.”

  Predicting such outcomes is one way the team’s AI models can come into play. In a related paper in Nature Communications, Lively and Finn, together with researchers in Rampi Ramprasad’s lab at Georgia Tech, described using machine-learning algorithms and mass-transport simulations to predict the performance of polymer membranes in complex separations.

  “This entire pipeline, I think, is a significant development, and it's also the first step toward actual materials design,” said Ramprasad, professor in the School of Materials Science and Engineering. “We call this a ‘forward problem’, meaning you have a material and a mixture that goes in – what comes out? That's a prediction problem. What we want to do eventually is to design new polymers that achieve a certain target permeation performance.”

  Complex mixtures like crude oil might have hundreds or thousands of components, so accurately describing each compound in mathematical terms, how it interacts with the membrane and extrapolating the outcome is ‘non-trivial’, as Ramprasad put it.

  Training the algorithms also involved combing through all the experimental literature on solvent diffusion through polymers to build an enormous dataset. But, like the potential of membranes themselves to reshape refining, knowing ahead of time how a proposed polymer membrane might work would accelerate a materials-design process that’s basically trial-and-error now.

  “The default approach is to make the material and test it, and that takes time,” Ramprasad said. “This data-driven or machine-learning-based approach uses past knowledge in a very efficient manner. It’s a digital partner: you’re not guaranteed an exact prediction, because the model is limited by the space spanned by the data you use to train it. But it can extrapolate a little bit and it can take you in new directions, potentially. You can do an initial screening by searching through vast chemical spaces and make ‘go, no-go’ decisions up front.”

  Lively said he’d long been a skeptic about the ability of machine-learning tools to tackle the kinds of complex separations he works with. “I always said, ‘I don't think you can predict the complexity of transport through polymer membranes. The systems are too big; the physics are too complicated. Can't do it.’”

  But then he met Ramprasad: “Rather than just be a naysayer, Rampi and I took a stab at it with a couple of undergrads, built this big database, and dang. Actually, you can do it.”

  Developing the AI tools also involved comparing the algorithms’ predictions to actual results, including with the DUCKY polymer membranes. The experiments showed the AI models predictions were within 6% to 7% of actual measurements.

  “It's astonishing,” Finn said. “My career has been spent trying to predict what molecules are going to do. The machine-learning approach, and Rampi’s execution of it, is just completely revolutionary.”

  This story is adapted from material from Georgia Tech, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 16, 2023

• Materials Today -- News Metal nanoclusters and graphene boost lithium–sulfur batteries

  Schematic of a lithium-sulfur battery with the Au24Pt(PET)18@G-modified battery separator. Image: Yuichi Negishi from TUS Japan.

  The demand for efficient energy-storage systems is ever increasing, spurred by the emergence of intermittent renewable energy sources and the adoption of electric vehicles. In this regard, lithium–sulfur batteries (LSBs), which can store three to five times more energy than traditional lithium-ion batteries, have emerged as a promising solution.

  LSBs use lithium as the anode and sulfur as the cathode, but this combination poses challenges. One significant issue is the ‘shuttle effect’, in which intermediate lithium polysulfide (LiPS) species migrate between the anode and cathode, resulting in capacity fading, low life cycle and poor rate performance.

  Other problems include the expansion of the sulfur cathode during lithium-ion absorption and the formation of insulating lithium–sulfur species and lithium dendrites during battery operation. While various approaches, including cathode composites, electrolyte additives and solid-state electrolytes, have been employed to address these challenges, they all involve trade-offs that limit further development of LSBs.

  Recently, atomically precise metal nanoclusters, aggregates of metal atoms ranging from 1nm to 3nm in size, have received considerable attention in materials research, including for LSBs, owing to their high designability and unique geometric and electronic structures. However, while many suitable applications for metal nanoclusters have been suggested, there are still no examples of their practical use.

  Now, in a paper in Small, a team of researchers from Japan and China, led by Yuichi Negishi at the Tokyo University of Science (TUS), report harnessing the surface-binding property and redox activity of platinum (Pt)-doped gold (Au) nanoclusters, Au₂₄Pt(PET)₁₈ (PET: phenylethanethiolate), as a high-efficiency electrocatalyst for LSBs.

  The researchers prepared composites of Au₂₄Pt(PET)₁₈ and graphene (G) nanosheets, which possess a large specific surface area, high porosity and a conductive network. They then used these composites to develop a battery separator that can accelerate the electrochemical kinetics of LSBs.

  “The LSBs assembled using the Au₂₄Pt(PET)₁₈@G-based separator arrested the shuttling LiPSs, inhibited the formation of lithium dendrites and improved sulfur utilization, demonstrating excellent capacity and cycling stability,” said Negishi.

  This led to an improved energy density, longer cycle life, enhanced safety features and a reduced environmental impact, making the LSBs more environmentally friendly and competitive with other energy-storage technologies.

  “LSBs with metal nanoclusters may find applications in electric vehicles, portable electronics, renewable energy storage and other industries requiring advanced energy-storage solutions,” said Negishi. “In addition, this study is expected to pave the way for all-solid-state LSBs with more novel functionalities.”

  In the near future, the proposed technology can lead to cost-efficient and longer-lasting energy storage devices. This would help reduce carbon emissions and support the adoption of renewable energy, promoting sustainability.

  This story is adapted from material from the Tokyo University of Science, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 13, 2023

• Materials Today -- News Cracking crystal finding with electron beam

  These electron microscope images show how the crack in a crystal of titanium dioxide begins to heal with increasing electron doses. Image: Mkoyan Group, University of Minnesota.

  In a surprising new study, researchers at the University of Minnesota have found that the electron beam radiation that they previously thought degraded crystals can actually repair cracks in these nanostructures.

  This groundbreaking discovery, reported in a paper in Nature Communications, provides a new pathway to creating more perfect crystal nanostructures, a process that is critical to improving the efficiency and cost-effectiveness of materials that are used in virtually all electronic devices we use every day.

  “For a long time, researchers studying nanostructures were thinking that when we put the crystals under electron beam radiation to study them that they would degrade,” said Andre Mkhoyan, a chemical engineering and materials science professor at the University of Minnesota and lead researcher of the study. “What we showed in this study is that when we took a crystal of titanium dioxide and irradiate it with an electron beam, the naturally occurring narrow cracks actually filled in and healed themselves.”

  The researchers accidentally stumbled upon this discovery when using the University of Minnesota’s state-of-the-art electron microscope to study the crystals for a completely different reason.

  “I was studying the cracks in the crystals under the electron microscope and these cracks kept filling in,” said Silu Guo, a chemical engineering and materials science PhD student at the University of Minnesota. “This was unexpected, and our team realized that maybe there was something even bigger that we should be studying.”

  In the self-healing process, several atoms of the crystal move together in tandem and meet in the middle to form a sort of bridge that fills the crack. For the first time, the researchers showed that electron beams could be used constructively to engineer novel nanostructures atom-by-atom.

  "Whether it's atomically sharp cracks or other types of defects in a crystal, I believe it's inherent in the materials we've grown, but it's truly astonishing to see how Professor Mkhoyan's group can mend these cracks using an electron beam," said Bharat Jalan, a chemical engineering and materials science professor at the University of Minnesota and a collaborator on the research.

  The researchers say the next step is to introduce new factors, like changing the electron beam conditions or changing the temperature of the crystal, to find a way to improve or speed up the process. “First we discovered, now we want to find more ways to engineer the process,” Mkhoyan said.

  This story is adapted from material from the University of Minnesota, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Oxygen-generating microparticles boost bone repair

  Schematic of the effect of OMP, silicate nanoparticles (SNP), and SNP/OMP on the differentiation of human stem cells towards osteogenesis under normal oxygen and depleted oxygen conditions (normoxia and anoxia, respectively).

  Engineered biomaterial scaffolds embedded with cells for treating bone-related traumas like severe fractures can suffer from a lack of oxygen, especially when a large implant is required. An oxygen supply is vital not only to catalyze cell metabolism and tissue regeneration, but also to support the development of blood vessels, collagen, and other extracellular matrix components. Introducing the ability to release oxygen from implants offers a potential approach to improving bone tissue engineering and regeneration.

  Now researchers have developed hydrogels incorporating oxygen-generating microparticles (OMPs) that drive the differentiation of human stem cells into osteoblasts, boosting the potential for regenerative medicine [Hassan et al., Biomaterials 300 (2023) 122179, https://doi.org/10.1016/j.biomaterials.2023.122179].

  “As a result of limitations in biofabrication, it is still not possible to fabricate clinical-sized engineered living implants that can be sustained for more than a couple of weeks or succeed as potential biomaterials for long-term use,” explains first author of the study, Shabir Hassan of Khalifa University in the United Arab Emirates.

  Together with colleagues at Harvard Medical School and Brigham and Women’s Hospital, Broad Institute of MIT and Harvard, University of Illinois Chicago, University Twente in the Netherlands, Incheon National University in South Korea, Sichuan University and Nanjing Medical University in China led by Jeroen Leijten and Su Ryon Shin, the researchers have developed a platform that not only provides a vascularization-inducing oxygenating microenvironment but also tailorable mechanical properties. The OMPs based on calcium peroxide release oxygen over a prolonged period, while silicate nanoparticles provide mechanical robustness.

  Stem cells introduced into the platform can be induced to differentiate into specific tissues such as bone or cartilage, depending on the environmental conditions. In vitro, the researchers observed that OMPs improve cell survival and proliferation, while self-oxygenation supports enhanced vascularization.  

  “By introducing oxygenating micro-materials, our platform can be used to make thicker tissues and, by changing the environmental conditions, [we can] choose whether we make bone or cartilage,” says Hassan.

  Oxygenating implants during the initial period of vascular development is particularly crucial, believe the researchers. The incorporation of oxygen-generating biomaterials into implant scaffolds is a promising approach to improving outcomes in the formation of functional living tissue when treating bone traumas.

  “Our preliminary results suggest our approach is practical,” points out Hassan. “However, bone formation and osteogenesis are very complex biological processes [and] more studies are needed to understand the mechanism of action of these oxygenating micro-materials.

October 12, 2023

• Materials Today -- News Positive results from positron bombardment

  The slow positron beam apparatus used to fire positrons at a lithium fluoride crystal. Image: Professor Yasuyuki Nagashima from Tokyo University of Science.

  A positron is the antiparticle of an electron, with the same mass and spin as an electron but the opposite charge. It is an attractive particle for scientists, having led to important insights and developments in the fields of elementary particle physics, atomic physics, materials science, astrophysics and medicine. For example, positrons are known to be components of antimatter. They can also be used to detect lattice defects in solids and semiconductors, and for the structural analysis of the topmost surface of crystals.

  Positronic compounds, namely bound states of positrons with regular atoms, molecules or ions, represent an intriguing aspect of positron–matter interactions and have been studied experimentally via observation of positron annihilation in gases. It may even be possible to generate new molecules and ions via the formation of positron compounds, but no research has ever been done from such a perspective.

  Now, a research team that includes Yasuyuki Nagashima from Tokyo University of Science (TUS), Japan, has discovered an innovative way to explore the interactions between positrons and ionic crystals. This work, reported in a paper in Physical Review Letters, involved collaborative efforts from Takayuki Tachibana, a former assistant professor at TUS who is currently affiliated with Rikkyo University in Japan, and Daiki Hoshi, a former graduate student at TUS.

  The researchers used a technique based on a well-explored phenomenon that occurs when a solid is bombarded with an electron beam. “It has long been known that when electrons are injected into a solid surface, atoms that make up the surface are ejected as monoatomic positive ions,” explains Tachibana. This process, known as electron-stimulated desorption, motivated the team to explore what would happen if a crystal was bombarded with positrons rather than electrons.

  In their experiments, the researchers fired a beam of either positrons or electrons at the (110) surface of a lithium fluoride (LiF) crystal. Using carefully placed electric fields generated by deflectors, they could control the incident energies of the charged particles. Moreover, the deflectors allowed them to redirect any ions desorbed from the crystal towards an ion detector. The detected signals were then used to conduct a spectroscopic analysis to identify the precise composition of the desorbed ions.

  They found that when the LiF crystal was bombarded with electrons, only the expected monoatomic ions, namely Li⁺, F⁺ and H⁺ (due to residual gases in the experimental chamber) were detected. However, bombarding the crystal with positrons led to the detection of positive molecular fluorine ions (F₂⁺) and positive hydrogen fluoride ions (FH⁺). Notably, this is the first-ever report of molecular ions being ejected on bombardment with positrons.

  After further analysis and experimentation, the researchers developed a desorption model to explain their observations. According to this model, as positrons are injected into a solid, some of them return to the surface after losing their energy. In the case of LiF crystals, these positrons may attract two neighboring negative fluorine ions on the surface to form a positronic compound. If the bound positron annihilates one of the fluorine ion’s core electrons, a special type of electron, known as an Auger electron, is emitted, resulting in a charge swap and the generation of a F₂⁺ ion. This ion is pushed out of the crystal by the repulsing forces of the nearby Li⁺ ions.

  The findings of this study could further scientists’ understanding of matter–antimatter interactions. “The stability and binding properties of positronic compounds provide unique perspectives on the interaction of antiparticles with ordinary substances, paving the way for novel investigations in the field of quantum chemistry,” says Tachibana. “The proposed method could thus pave the way for the generation of new molecular ions and molecules in the future.”

  Notably, this approach could be leveraged in many applied fields. In materials science, it could be used to modify the surface of materials and study their properties with unprecedented precision. Other potential applications include cancer therapy, quantum computing, energy storage and next-generation electronic devices.

  This story is adapted from material from Tokyo University of Science, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Novel magnetoelectric material strikes a nerve

  A sample of the magnetoelectric nonlinear metamaterial, which is 120 times faster at stimulating neural activity than previously used magnetic materials. Image courtesy of the Robinson lab/Rice University.

  Researchers have long recognized the therapeutic potential of using magnetoelectrics ? materials that can turn magnetic fields into electric fields ? to stimulate neural tissue in a minimally invasive way and help treat neurological disorders or nerve damage. The problem, however, is that neurons have a hard time responding to the shape and frequency of the electric signal resulting from this conversion.

  Now, Jacob Robinson and his team at Rice University have designed the first magnetoelectric material that not only solves this issue but performs the magnetic-to-electric conversion 120 times faster than similar materials. In a paper in Nature Materials, the researchers report that the material can be used to precisely stimulate neurons remotely and to bridge the gap in a broken sciatic nerve in a rat model.

  According to Robinson, a professor of electrical and computer engineering and bioengineering, the material’s qualities and performance could have a profound impact on neurostimulation treatments, making for significantly less invasive procedures. Instead of implanting a neurostimulation device, tiny amounts of the material could simply be injected at the desired site. Moreover, given magnetoelectrics’ range of applications in computing, sensing, electronics and other fields, this research provides a framework for advanced materials design that could drive innovation more broadly.

  “We asked, ‘Can we create a material that can be like dust or is so small that by placing just a sprinkle of it inside the body you’d be able to stimulate the brain or nervous system?’” said Joshua Chen, a Rice doctoral alumnus who is a lead author of the paper. “With that question in mind, we thought that magnetoelectric materials were ideal candidates for use in neurostimulation. They respond to magnetic fields, which easily penetrate into the body, and convert them into electric fields – a language our nervous system already uses to relay information.”

  The researchers started with a magnetoelectric material made up of a piezoelectric layer of lead zirconium titanate sandwiched between two magnetorestrictive layers of metallic glass alloy, or Metglas, which can be rapidly magnetized and demagnetized.

  Gauri Bhave, a former researcher in the Robinson lab who now works in technology transfer for Baylor College of Medicine, explained that the magnetorestrictive element vibrates on application of a magnetic field.

  “This vibration means it basically changes its shape,” she said. “The piezoelectric material is something that, when it changes its shape, creates electricity. So when those two are combined, the conversion that you’re getting is that the magnetic field you’re applying from the outside of the body turns into an electric field.”

  Unfortunately, the electric signals generated by magnetoelectrics are too fast and uniform for neurons to detect. The challenge was thus to engineer a new material that could generate an electric signal that would actually get cells to respond.

  “For all other magnetoelectric materials, the relationship between the electric field and the magnetic field is linear, and what we needed was a material where that relationship was nonlinear,” Robinson said. “We had to think about the kinds of materials we could deposit on this film that would create that nonlinear response.”

  They ended up layering platinum, hafnium oxide and zinc oxide and then adding these stacked materials on top of the original magnetoelectric film. One of the challenges they faced was finding fabrication techniques compatible with the materials.

  “A lot of work went into making this very thin layer of less than 200nm that gives us the really special properties,” Robinson said.

  “This reduced the size of the entire device so that in the future it could be injectable,” Bhave added.

  As proof of concept, the researchers used the material to stimulate peripheral nerves in rats and demonstrated the material’s potential for use in neuroprosthetics by showing it could restore function in a severed nerve.

  “We can use this metamaterial to bridge the gap in a broken nerve and restore fast electric signal speeds,” Chen said. “Overall, we were able to rationally design a new metamaterial that overcomes many challenges in neurotechnology. And more importantly, this framework for advanced material design can be applied toward other applications like sensing and memory in electronics.”

  Robinson, who drew on his doctoral work in photonics for inspiration in engineering the new material, said he finds it “really exciting that we can now design devices or systems using materials that have never existed before rather than being confined to ones in nature”.

  “Once you discover a new material or class of materials, I think it’s really hard to anticipate all the potential uses for them,” he added. “We’ve focused on bioelectronics, but I expect there may be many applications beyond this field.”

  This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 11, 2023

• Materials Today -- News X-rays reveal emerging microstructures in 3D-printed alloy

  Adrita Dass (left), Chenxi Tian (middle) and Atieh Moridi (right) created a portable twin of their 3D-printing setup. Image: Cornell University.

  Researchers at Cornell University took a novel approach to exploring the way microstructure emerges in a 3D-printed metal alloy – they bombarded it with X-rays while the material was being printed.

  By seeing how the process of thermomechanical deformation creates localized microscale phenomena such as bending, fragmentation and oscillation in real time, the researchers will be able to produce customized materials that incorporate performance-enhancing characteristics. They report their work in a paper in Communications Materials.

  “We always look at these microstructures after processing, but there’s a lot of information that you’re missing by conducting only postmortem characterizations,” said Atieh Moridi, assistant professor in the Sibley School of Mechanical and Aerospace Engineering in Cornell Engineering and the paper’s senior author. “Now we have tools to be able to watch these microstructural evolutions as they are happening. We want to be able to understand how these tiny patterns or microstructures are formed because they dictate everything about performance of printed parts.”

  The group focused on a form of 3D printing in which a powder – in this case, the nickel-based superalloy IN625, widely used in additive manufacturing and the aerospace industry – is applied via nozzle and melted by a high-power laser beam, then cools and solidifies.

  Since it is not feasible to access high-energy X-rays in the lab, the researchers created a portable twin of their 3D-printing setup and brought it to the Center for High Energy X-ray Sciences at the Cornell High Energy Synchrotron Source (CHEXS@CHESS).

  The facility had never conducted this type of 3D-printing experiment before, so the CHESS beamline scientist Darren Pagan, now assistant professor at Pennsylvania State University, worked with the researchers to integrate the printer setup into one of the facility’s experiment hutches. The CHESS team also developed crucial safety protocols for operating a high-power laser along with flammable powders.

  During the experiment at the FAST beamline, a focused X-ray beam was sent into the hutch, where it passed through the IN625 as it was heated, melted and cooled. A detector on the other side of the printer captured the patterns of diffraction that result from the X-rays interacting with the material.

  “The way these diffraction patterns form gives us a lot of information about the structure of the material,” Moridi said. “They are the microstructural fingerprints that capture the history of the material during the processing. Depending on the interaction and what caused it, we get different patterns, and from those patterns, we can back-calculate the structure of the material.”

  Typically, researchers would try to consolidate the huge amount of diffraction data in order to analyze it. But Moridi, together with doctoral students Adrita Dass and Chenxi Tian, took on a more challenging task and studied the raw detector images. While this approach required more time and was more labor-intensive, it provided a richer, holistic picture of how the IN625 took shape, revealing “unique features that most of the time we’re missing”, Moridi said.

  The group identified key microstructural features that were created by the 3D-printing process’s thermal and mechanical effects, including torsion, bending, fragmentation, assimilation, oscillation and interdendritic growth.

  The researchers anticipate their method can be applied to other 3D-printed metals, such as stainless steels, titanium and high-entropy alloys, or any material system with a crystal structure.

  The method can also help inform the development of sturdier materials. For example, pulsing a laser beam would increase fragmentation inside a crystal and reduce the size of its grains, making the material stronger.

  “The final goal is to have the best material system that we can have for that particular alloy for a particular application,” Dass said. “If you know what is happening during processing, you can choose how to process your materials, so you get those specific features.”

  This story is adapted from material from Cornell University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New study sheds light on removing dyes with nanofilaments

  This is an exciting finding because it helps to address a problem that has been a real challenge for the water-treatment process. We anticipate that integrating our titanium-oxide photocatalyst into the current processes could improve its effectiveness in removing these chemicals, as well as reducing the amount of energy required to do so.Michel Barsoum, Drexel University

  Discharged in large quantities by textile, cosmetic, ink, paper and other manufacturers, dyes carry high-toxicity and can bring potential carcinogens to wastewater. It’s a major concern for wastewater treatment – but researchers in Drexel University’s College of Engineering may now have found a solution, using a tiny nanofilament.

  A study lead Michel Barsoum, a professor in the College of Engineering, and his team found that a one-dimensional, lepidocrocite-structured titanium oxide photocatalyst material has the ability to break down two common dye pollutants — rhodamine 6G and crystal violet — when illuminated with visible light. Using an equal ratio of dye to catalyst, it was able to reduce concentrations of the two dyes in water by 90% and 64%, respectively, in just 30 minutes.

  “This is an exciting finding because it helps to address a problem that has been a real challenge for the water-treatment process,” Barsoum said. “We anticipate that integrating our titanium-oxide photocatalyst into the current processes could improve its effectiveness in removing these chemicals, as well as reducing the amount of energy required to do so.”

  On encountering a nanofilament, the dye adheres to its surface and then undergoes photocatalysis when illuminated, with the dye sensitizing the nanofilaments to visible light. This process accelerates degradation, causing the dye to break apart into harmless byproducts such as carbon dioxide and water.

  The study, reported in a paper in Matter, found that the key to the dye degradation and self-sensitization process was the ability of the material to generate electron holes and reactive oxygen species.

  The two dyes are common effluents in wastewater. Effluent, which literally means something that flows out, is different to the sewage found in wastewater. While solid waste can be filtered out before the water is purified, effluent is suspended in the water, making it hard to separate and remove.

  Rhodamine 6G is a xanthene-derived dye primarily used in wood processing, paper dyeing, pen ink and cosmetics. Crystal violet, a triphenylmethane dye, is used to dye ink and textiles. These dyes are water soluble and any excess is discharged as effluent.

  Wastewater is a major environmental concern worldwide and its existence has long-term impacts on the health of humans, aquatic plants and animals. Households and industry generate nearly 380 billion cubic tons of wastewater globally each year. Only 24% of this is treated sufficiently due to various challenges, including high energy consumption, the existence of residual chemicals, and the insufficient processing of complex and persistent contaminants, including dyes.

  According to the researchers, the most common wastewater treatment methods, such as sedimentation, biological oxidation and chemical-physical treatment, are ineffective at removing dyes, due to the dyes’ complex molecular structure and water-soluble nature.

  Adsorption of dyes by clay materials, activated carbon, iron oxide and natural materials such as coffee grounds has been tried before and exhibited high uptakes. However, these materials simply separate the dye from the water — the dye still exists and is simply attached to the adsorbent materials within the wastewater.

  Photocatalysts, long thought to be the key to removing dyes from water, have thus far not produced a sustainable solution. According to Barsoum, many photocatalysts typically require UV light treatment, which uses extensive energy. The impact of the new nanofilament resides in its self-sensitization behavior, which makes the nanofilament more sensitive to visible light.

  “The use of visible light – light the human eye can see – like the sun or other simulated light sources, could significantly reduce the financial and energy consumption costs associated with treatment, while still being highly effective at removing dyes from wastewater, eliminating the toxic effluents,” said Adam Walter, a doctoral student in Barsoum’s research group, and first author of the paper. “This also presents an exciting opportunity for expansion into other fields like solar cells or optical devices.”

  The team used X-ray diffraction to characterize the arrangement of atoms in the nanofilaments. They further characterized them using scanning and transmission electron microscopy, which fires beams of electrons at the material to form an image. To assess dye decolorization, the team monitored the sample using ultraviolent-visible spectroscopy and quantified mineralization by chemical oxygen demand.

  One of the most important findings of the study was strong evidence that the nanofilament is sensitized by the dye, representing a symbiotic relationship between the additive and effluent that resulted in cleaner, less toxic water. One way of thinking about this, Walter said, is that the dye catalyzes its own destruction.

  This sensitization opens the door to using the nanofilament for applications in solar cells and optical devices. Earlier this year, the same nanofilament was studied by the team and found to harness sunlight for hydrogen separation, which could unlock its potential in green-fuel generation.

  “We are just beginning to uncover the possibilities of this material,” Barsoum said. “As we better understand the processes enabling its behavior, we anticipate exploring new applications where it could improve the performance of technology that the world needs to move toward a more sustainable future.”

  This story is adapted from material from Drexel University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 10, 2023

• Materials Today -- News Excitons display magnetic attraction in Mott insulators

  In materials known as antiferromagnetic Mott insulators, electrons (orbs) are organized in a lattice structure of atoms such that their spins point up (blue) or down (pink) in an alternating pattern. This is a stable state in which the energy is minimized. When the material is hit with light, an electron will hop to a neighboring atomic site, leaving a positively charged hole where it once resided (dark orb). If the electron and hole move further apart from each other, the spin arrangement between them becomes disturbed the spins are no longer pointing in opposite directions to their neighbors as seen in the second panel and this costs energy. To avoid this energy penalty, the electron and hole prefer to remain close to each other. This is the magnetic binding mechanism underlying the Hubbard exciton. Image: Caltech.

  In art, the negative space in a painting can be just as important as the painting itself. Something similar is true in insulating materials, where the empty spaces left behind by missing electrons play a crucial role in determining the material's properties.

  When a negatively charged electron is excited by light, it leaves behind a positive hole. Because the hole and the electron are oppositely charged, they are attracted to each other and form a bond. The resulting pair, which is short lived, is known as an exciton.

  Excitons are a key part of many technologies, including solar panels, photodetectors and sensors, as well as the light-emitting diodes found in televisions and digital display screens. In most cases, the exciton pairs are bound by electrical, or electrostatic, forces, also known as Coulomb interactions.

  Now, in a new paper in Nature Physics, researchers at California Institute of Technology (Caltech) report detecting excitons that are not bound via Coulomb forces but rather by magnetism. This is the first experiment to detect how these so-called Hubbard excitons, named after the late physicist John Hubbard, form in real-time.

  "Using an advanced spectroscopic probe, we were able to observe in real time the generation and decay of magnetically bound excitons, the Hubbard excitons," says Omar Mehio, lead author of the paper and a recent graduate student at Caltech who worked with David Hsieh, a professor of physics at Caltech. Mehio is now a postdoctoral fellow at the Kavli Institute at Cornell University.

  "In most insulators, oppositely charged electrons and holes interact with one another just as an electron and a proton bind to form a hydrogen atom," Mehio explains. "However, in a special class of materials known as Mott insulators, the photo-excited electrons and holes instead bind through magnetic interactions."

  These results could have applications in the development of new exciton-related technologies, or excitonics, in which the excitons would be manipulated through their magnetic properties.

  "Hubbard excitons and their magnetic binding mechanism demonstrate a drastic departure from the paradigms of traditional excitonics, creating the opportunity to develop a whole ecosystem of novel technologies that are fundamentally unavailable in conventional excitonic systems," Mehio says. "Having excitons and magnetism strongly intertwined in a single material could lead to new technologies that harness both properties."

  To create the Hubbard excitons, the researchers applied light to a type of insulating material known as an antiferromagnetic Mott insulator. These are magnetic materials in which the electron spins are aligned in a repeating, stable pattern. The light excites the electrons, which jump to other atoms, leaving holes behind.

  "In these materials, when an electron or hole moves through the lattice, they leave in their wake a string of magnetic excitations," Mehio says. "Imagine you tie one end of an elastic rope around your friend, and the other end around yourself. If your friend runs away from you, you will feel the rope pull you in that direction and you will begin to follow. This scenario is analogous to what happens between a photo-excited electron and the hole it leaves behind in a Mott insulator. With Hubbard excitons, the string of magnetic excitations between the pair serves the same role as the rope connecting you to your friend."

  To demonstrate the existence of the Hubbard excitons, the researchers used a method called ultrafast time-domain terahertz spectroscopy, which allowed them to look for the very short-lived signatures of the excitons at very low-energy scales. "Excitons are unstable because the electrons want to go back into the holes," Hsieh explains. "We have a way of probing the short time window before this recombination occurs, and that allowed us to see that a fluid of Hubbard excitons is transiently stabilized."

  This story is adapted from material from Caltech, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Mighty morphing all-inorganic perovskites

  CityU researchers show off a photodetector constructed with the morphed perovskites. Photo: City University of Hong Kong.

  A research team co-led by scholars from City University of Hong Kong (CityU) has shown that all-inorganic perovskites can be deformed and morphed at room temperature without compromising their functional properties. Their findings, reported in a paper in Nature Materials, demonstrate the potential of this class of semiconductors for manufacturing next-generation deformable electronics and energy systems in the future.

  All-inorganic lead halide perovskites are becoming increasingly important semiconducting materials in energy conversion and optoelectronics because of their outstanding performance and enhanced environmental stability.

  “However, unlike metal materials or polymers, inorganic semiconductors are often brittle and hard to process,” said Chen Fu-Rong, associate vice-president (mainland collaboration) and professor of materials science at CityU, who co-led the study. “This strongly restricts their applications as optoelectronic products that must withstand mechanical stress and strain without losing their functionality.”

  To overcome this limitation, Chen and his research team explored the deformability of an all-inorganic perovskite (CsPbX₃, where X can be chlorine, bromine or iodine ions). They found that perovskites can be substantially morphed into distinct geometries at room temperature while preserving their functional properties, an achievement unprecedented in conventional inorganic semiconductors.

  In their experiments, the team using the vapour-liquid-solid method to synthesize single-crystal micropillars of CsPbX₃ with diameters and widths ranging from 0.4μm to 2μm and lengths ranging from 3μm to 10μm. They then conducted in situ compression experiments with a scanning electron microscope.

  These revealed that, under compression, there were continuous slips of partial dislocations on multiple slip systems in the CsPbX₃ crystal lattice. This ‘domino-like’ multi-slipping deformation mechanism allowed the micropillars to deform into various distinct shapes without fracturing, including an upside-down L shape, a Z shape and a wine-glass shape.

  With the aid of an atomic-resolution transmission electron microscope (TEM), the team discovered that the atoms in the deformation zone were well connected, leading to undamaged functional properties. “We also observed that the optoelectronic performance of the micropillars remained unaffected by the deformation,” said Johnny Ho Chung-yin, associate head and professor in the Department of Materials Science and Engineering (MNE) at CityU. “This demonstrates the potential of these materials for use in deformable optoelectronics.”

  The research team performed further electronic and structural analyses to uncover the physical origin of this unusual behaviour. “The secret of the morphing ability is the low-slip energy barrier, which ensures facile slips, and the strong Pb–X bonds, which maintain the crystal’s structural integrity and prevent cracking or cleaving,” said Zhao Shijun, who specializes in the properties of computational materials at MNE. And the bandgap – an energy index influencing the total electrical properties of intrinsic semiconductors – of the CsPbX₃ crystal lattice remained unchanged after deformation, indicating that the electronic structure of the material was unaffected.

  “Our results demonstrated that all-inorganic CsPbX₃ single crystals can be substantially deformed and facilely morphed into various shapes through multi-slipping under ambient conditions, without changing their crystalline integrity, lattice structure or optoelectronic properties,” said Chen.

  “This achievement represents a significant step towards designing and manufacturing innovative energy devices and deformable electronics. The underlying mechanism, uncovered by a TEM at the atomic level provides important implications for seeking other intrinsic ductile semiconductors.”

  This story is adapted from material from City University of Hong Kong, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 09, 2023

• Wrocław University of Science and Technology TOP 2%: 62 scientists from Wroclaw Tech in prestigious ranking
  48 people on the main list and 38 on the 2022 list - these are the results of researchers from the Wroclaw Tech in the latest edition of the prestigious ranking of the world's most influential people in science.

October 06, 2023

• Materials Today -- News Diamond dislocations break sound barrier

  Illustration of an intense laser pulse hitting a diamond crystal from top right, driving elastic and plastic waves (curved lines) through the material. The laser pulse creates linear defects, known as dislocations, at the points where it hits the crystal. These dislocations propagate through the material faster than the transverse speed of sound, leaving stacking faults the lines fanning out from the impact site behind. Image: Greg Stewart/SLAC National Accelerator Laboratory.

  Settling a half century of debate, researchers have discovered that tiny linear defects can propagate through a crystalline material faster than sound waves. These linear defects, or dislocations, are what give metals their strength and workability, but they can also make materials fail catastrophically – which is what happens every time you pop the pull tab on a can of soda.

  The fact that these dislocations can travel so fast gives scientists a new appreciation of the unusual types of damage they might do to a broad range of materials under extreme conditions – from rock ripped apart by an earthquake rupture to aircraft-shielding materials deformed by extreme stress.

  “Until now, no one has been able to directly measure how fast these dislocations spread through materials,” said Leora Dresselhaus-Marais, a professor at the US Department of Energy’s SLAC National Accelerator Laboratory and Stanford University, who co-led the study with Norimasa Ozaki at Osaka University in Japan.

  Her team used X-ray radiography – similar to medical X-rays that reveal the inside of the body – to clock the speed of propagating dislocations through diamond, yielding lessons that should apply to other materials too. The researchers report their results in a paper in Science.

  Scientists have been debating whether dislocations can travel through materials faster than sound for nearly 60 years. A number of studies concluded that they could not. But some computer models indicated that yes, they could – provided they started out moving at faster-than-sound speed.

  Getting sound waves instantaneously up to this speed would require a tremendous shock. For one thing, sound travels a lot faster through solid materials than it does through air or water, depending on the nature and temperature of the material, among other factors. While the speed of sound through air is generally given as 761mph, it’s 3355mph through water and an incredible 40,000mph through diamond, the hardest material of all.

  Complicating things even more, there are two types of sound waves in solids. Longitudinal waves are like the ones in air. But because solids put up some resistance to the passage of sound, they also host slower-moving waves known as transverse sound waves.

  Knowing whether ultrafast dislocations can break either of these sound barriers is important from both a fundamental science and practical perspective. When dislocations move faster than the speed of sound, they behave quite differently and result in unexpected failures that have thus far only been modeled. Without measurements, no one knows how much damage those ultrafast dislocations can do.

  “If a structural material fails more catastrophically than anyone expected because of its high rate of failure, that’s not so good,” said Kento Katagiri, a postdoctoral scholar in the research group and first author of the paper. “If it’s a fault rupturing through rock during an earthquake, for instance, it could cause more damage to everything. We need to learn more about this type of catastrophic failure.”

  According to Dresselhaus-Marais, the results of this study “could suggest that what we thought we knew about the fastest possible materials failure was wrong”.

  To get the first direct images of how fast dislocations can travel, Dresselhaus-Marais and her colleagues performed experiments at the SACLA X-ray free-electron laser in Japan. They did the experiments on tiny crystals of synthetic diamond.

  Diamond offers a unique platform to study how crystalline materials fail. For one thing, its deformation mechanism is simpler than those observed in metals, making it easier to interpret these challenging ultrafast X-ray imaging experiments.

  “To understand the damage mechanisms, we need to identify features in our images that are unambiguously dislocations, and not other types of defects,” Katagiri said.

  When two dislocations meet, they attract or repel each other and generate even more dislocations. Pop open a can of soda made from an aluminum alloy, and the many dislocations that are already in the lid – created when it was shaped into its final form – interact and spawn new dislocations by the trillions, which cascade into absolute critical failure as the top of the can flexes and the pop top snaps open. Those interactions and how they behave govern all the mechanical properties of materials we observe.

  “In diamond, there are only four types of dislocation, while iron, for instance, has 144 different possible types of dislocations,” Dresselhaus-Marais said. Diamond may be much harder than metal, but much like a soda can, it will still bend by forming billions of dislocations if it’s shocked hard enough.

  At SACLA, the team used intense laser light to generate shock waves in diamond crystals. Then they essentially took a series of ultrafast X-ray images of the dislocations forming and spreading on a timescale of billionths of a second. Only X-ray free-electron lasers can provide X-ray pulses short enough and bright enough to capture this process.

  They found that the initial shock wave split into two types of waves that continued to travel through the crystal. The first wave, called an elastic wave, temporarily deformed the crystal; its atoms bounced back into their original positions right away, like a rubber band that’s been stretched and released. The second wave, known as a plastic wave, permanently deformed the crystal by creating small errors in the repeating patterns of atoms that make up the crystal structure.

  These tiny shifts, or dislocations, create ‘stacking faults’ where adjacent layers of the crystal shift with respect to each other so they don’t line up the way they should. These stacking faults propagate outward from where the laser hit the diamond, and there is a moving dislocation at the leading tip of each stacking fault.

  With X-rays, the researchers discovered that the dislocations spread through diamond faster than the speed of the slower type of sound waves, the transverse waves – a phenomenon that had never been seen in any material before.

  Now, Katagiri said, the team plans to go back to an X-ray free-electron facility, such as SACLA or SLAC’s Linac Coherent Light Source (LCLS), to see if dislocations can travel faster than the higher-speed longitudinal sound waves in diamond, which will require even more powerful laser shocks. If and when the dislocations break that sound barrier, he said, they will be considered truly supersonic.

  This story is adapted from material from SLAC National Accelerator Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News New ruler for measuring twisted quantum materials

  This Illustration depicts two bilayers (two double layers) of graphene, which the NIST team employed in their experiments to investigate some of the exotic properties of moiré quantum material. Inset at left provides a top-level view of a portion of the two bilayers, showing the moiré pattern that forms when one bilayer is twisted at a small angle relative to the other. Image: B. Hayes/NIST.

  A single-atom-thick sheet of carbon known as graphene has remarkable properties on its own, but things can get even more interesting when you stack up multiple sheets. When two or more overlying sheets of graphene are sightly misaligned – twisted at certain angles relative to each other – they take on a plethora of exotic identities. Depending on the twist angle, these materials, known as moiré quantum matter, can suddenly generate their own magnetic fields, become superconductors with zero electrical resistance or, conversely, turn into perfect insulators.

  Joseph Stroscio and his colleagues at the US National Institute of Standards and Technology (NIST), together with an international team of collaborators, have now developed a ‘quantum ruler’ to measure and explore the strange properties of these twisted materials. This work, reported in a paper in Science, may also lead to a new, miniaturized standard for electrical resistance that could calibrate electronic devices directly on the factory floor, eliminating the need to send them to an off-site standards laboratory.

  Collaborator Fereshte Ghahari, a physicist from George Mason University, took two layers of graphene (known as bilayer graphene), each about 20µm across, and twisted them relative to another two layers to create a moiré quantum matter device. Ghahari made the device using the nanofabrication facility at NIST's Center for Nanoscale Science and Technology.

  NIST researchers Marlou Slot and Yulia Maximenko then chilled this twisted material device to one-hundredth of a degree above absolute zero, reducing random motions of atoms and electrons and heightening the ability of electrons in the material to interact. After reaching these ultralow temperatures, the researchers examined how the energy levels of electrons in the layers of graphene changed when they varied the strength of a strong external magnetic field. Measuring and manipulating the energy levels of electrons is critical for designing and manufacturing semiconductor devices.

  To measure the energy levels, the team used a versatile scanning tunneling microscope that Stroscio designed and built at NIST. When the researchers applied a voltage to the graphene bilayers in the magnetic field, the microscope recorded the tiny current from electrons that ‘tunneled’ out from the material to the microscope probe tip.

  In a magnetic field, electrons move in circular paths. Ordinarily, the circular orbits of the electrons in solid materials have a special relationship with an applied magnetic field: The area enclosed by each circular orbit, multiplied by the applied field, can only take on a set of fixed, discrete values, due to the quantum nature of electrons. In order to maintain that fixed product, if the magnetic field is halved, then the area enclosed by an orbiting electron must double.

  The difference in energy between successive energy levels that follow this pattern can be used like tick marks on a ruler to measure the material’s electronic and magnetic properties. Any subtle deviation from this pattern would represent a new quantum ruler that can reflect the orbital magnetic properties of the particular quantum moiré material the researchers are studying.

  In fact, when the NIST researchers varied the magnetic field applied to the moiré graphene bilayers, they found evidence of a new quantum ruler at play. The area enclosed by the circular orbit of electrons multiplied by the applied magnetic field no longer equaled a fixed value. Instead, the product of those two numbers had shifted by an amount dependent on the magnetization of the bilayers.

  This deviation translated into a set of different tick marks for the energy levels of the electrons. These findings promise to shed new light on how electrons confined to twisted sheets of graphene give rise to new magnetic properties.

  “Using the new quantum ruler to study how the circular orbits vary with magnetic field, we hope to reveal the subtle magnetic properties of these moiré quantum materials,” Stroscio said.

  In moiré quantum materials, electrons have a range of possible energies – highs and lows, shaped like an egg carton – that are determined by the electric field of the materials. The electrons are concentrated in the lower energy states, or valleys, of the carton. The large spacing between the valleys in the bilayers, bigger than the atomic spacing in any single layer of graphene or multiple layers that aren’t twisted, accounts for some of the unusual magnetic properties the team found, said NIST theoretical physicist Paul Haney.

  Because the properties of moiré quantum matter depend on the specific twist angle and number of atomically thin layers, the new measurements promise to provide a deeper understanding of how scientists can tailor and optimize the magnetic and electronic properties of quantum materials for a host of applications in microelectronics and related fields. For instance, ultrathin superconductors are already known to be exquisitely sensitive detectors of single photons, and quantum moiré superconductors rank among the very thinnest.

  The NIST team also has an interest in another application: under the right conditions, moiré quantum matter may provide a new, easier-to-use standard for electrical resistance.

  The present standard is based on the discrete resistance values that a material takes on when a strong magnetic field is applied to the electrons in a two-dimensional layer. This phenomenon, known as the quantum Hall effect, also originates from the quantized energy levels of the electrons in circular orbits. The discrete resistance values can be used to calibrate the resistance in various electrical devices. But because a hefty magnetic field is needed, the calibrations can only be conducted at a metrology facility such as NIST.

  According to Stroscio, if researchers could manipulate quantum moiré matter so that it has a net magnetization even in the absence of an external applied magnetic field, then it could potentially be used to create a new portable version of the most precise standard for resistance, known as the anomalous quantum Hall resistance standard. This would allow calibrations of electronic devices to be performed at the manufacturing site, potentially saving millions of dollars.

  This story is adapted from material from NIST, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Wrocław University of Science and Technology Over 1 million PLN to fund an international project with W4 involved
  Developing a tool to facilitate searching for court decisions is the main objective of the JuDDGES project, which involves researchers from Wrocław University of Science and Technology and two universities from France and the UK.

October 05, 2023

• Materials Today -- News Capturing carbon with MXene

  UCRs Mihri Ozkan. Photo: UCR.

  Some of the thinnest materials known to mankind may provide solutions to scientists in their quest to curb the effects of global warming.

  Known as MXene and MBene compounds, these substances are only a few atoms thick, making them two-dimensional (2D). Because of their large surface areas, these materials have the potential to absorb molecules of carbon dioxide from the atmosphere, helping to reduce the harmful effects of climate change by safely sequestering this potent greenhouse gas.

  In a paper in Chem, Mihri Ozkan and her colleagues at the University of California, Riverside (UCR) explain the potential of MXenes and MBenes for carbon-capture technologies.

  “In this review, we conducted an exhaustive analysis and proposed strategies for the widespread implementation of these materials in large-scale applications,” said Ozkan, a climate action professor in UCR’s Electrical and Computer Engineering Department at the Bourns College of Engineering. “Their unique properties make them excellent candidates for capturing carbon dioxide.”

  According to Ozkan, these 2D materials can be engineered to selectively capture carbon dioxide, via a process called interlayer distance engineering. What is more, the materials are mechanically stable and maintain their structural integrity even after multiple cycles of carbon capture and release.

  As human-caused carbon dioxide emissions continue to increase, developing carbon-capture technologies has become a top priority. It is projected that the planet's temperature could rise by 1.5°C above pre-industrial levels within the next decade, leading to more frequent severe weather events, worsening drought, crop failures, increased levels of human migration and political instability. These negative impacts highlight the urgent need for action to curb carbon emissions and mitigate the effects of climate change.

  Scientists at Drexel University discovered MXenes and MBenes in the early 2010s. MXene is an inorganic compound made up of atomically thin layers of transition metal carbides and nitrides or carbonitrides, while MBenes are dimensional transition metal borides made from boron. Both these materials are produced through chemical etching techniques and have crystalline lattices with repeating orthorhombic and hexagonal structures.

  Ozkan explained that these materials can be used in conjunction with existing carbon-capture technologies, such as those developed by the Swiss company Climework AS. These systems extract carbon dioxide directly from the atmosphere and sequester it for safe and long-term storage.

  But before these 2D materials can be used in carbon-capture devices, several technical issues need to be resolved. First and foremost, scientists must address the bottlenecks associated with synthesis-related challenges in large-volume production. Other obstacles to large-scale manufacturing include non-uniform mixing, temperature gradients and problems with heat transfer, among others.

  Still, these hurdles can be overcome. A top-down approach is ideal for large-scale MXene synthesis by scaling up wet-etching methods or developing new ones, says Ozkan.

  This story is adapted from material from the University of California, Riverside, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News Graphene oxide joins battle against Alzheimer's peptides

  Graphene oxide (orange) can enter yeast cells and reduce the toxicity of harmful protein aggregates (light grey), by promoting the disassembly and degradation of the aggregates. Image: Chalmers University of Technology/Katharina Merl.

  A probable early driver of Alzheimer's disease is the accumulation of molecules called amyloid peptides. These cause cell death and are commonly found in the brains of Alzheimer’s patients. Researchers at Chalmers University of Technology in Sweden have now shown that yeast cells that accumulate these misfolded amyloid peptides can recover after being treated with graphene oxide nanoflakes.

  Alzheimer’s disease is an incurable brain disease, leading to dementia and death, that causes suffering for both patients and their families. It is estimated that over 40 million people worldwide are living with the disease or a related form of dementia. According to Alzheimer’s News Today, the estimated global cost of these diseases is one percent of global gross domestic product.

  Misfolded amyloid-beta peptides (Aβ peptides) that accumulate and aggregate in the brain are believed to be the underlying cause of Alzheimer’s disease. They trigger a series of harmful processes in neurons (brain cells) – causing the loss of many vital cell functions or cell death, and thus a loss of brain function in the affected area. To date, there are no effective strategies for treating amyloid accumulation in the brain.

  Researchers at Chalmers University of Technology have now shown that treatment with graphene oxide leads to reduced levels of aggregated amyloid peptides in a yeast-cell model.

  “This effect of graphene oxide has recently also been shown by other researchers, but not in yeast cells,” says Xin Chen, a researcher in systems biology at Chalmers and first author of a paper on this work in Advanced Functional Materials. “Our study also explains the mechanism behind the effect. Graphene oxide affects the metabolism of the cells, in a way that increases their resistance to misfolded proteins and oxidative stress. This has not been previously reported.”

  In Alzheimer’s disease, the amyloid aggregates exert their neurotoxic effects by causing various cellular metabolic disorders, such as stress in the endoplasmic reticulum – a major part of the cell, in which many of its proteins are produced. This can reduce cells’ ability to handle misfolded proteins, and consequently increase the accumulation of these proteins.

  The aggregates also affect the function of mitochondria, the cells’ powerhouses. This exposes the neurons to increased oxidative stress (reactive molecules called oxygen radicals, which damage other molecules); something to which brain cells are particularly sensitive.

  The Chalmers researchers conducted this study using a combination of protein analysis (proteomics) and follow-up experiments. They used baker's yeast, Saccharomyces cerevisiae, as an in vivo model for human cells. Both cell types have very similar systems for controlling protein quality. This yeast-cell model was previously developed by the research group to mimic human neurons affected by Alzheimer’s disease.

  “The yeast cells in our model resemble neurons affected by the accumulation of amyloid-beta42, which is the form of amyloid peptide most prone to aggregate formation,” explains Chen. “These cells age faster than normal, show endoplasmic reticulum stress and mitochondrial dysfunction, and have elevated production of harmful reactive oxygen radicals.”

  Graphene oxide nanoflakes are two-dimensional carbon nanomaterials with unique properties, including outstanding conductivity and high biocompatibility. They are used extensively in various research projects, including the development of cancer treatments, drug-delivery systems and biosensors.

  The nanoflakes are hydrophilic (water soluble) and interact well with biomolecules such as proteins. When graphene oxide enters living cells, it can interfere with the self-assembly processes of proteins.

  “As a result, it can hinder the formation of protein aggregates and promote the disintegration of existing aggregates”, says Santosh Pandit, a researcher in systems biology at Chalmers and co-author of the paper. “We believe that the nanoflakes act via two independent pathways to mitigate the toxic effects of amyloid-beta42 in the yeast cells.”

  In one pathway, graphene oxide acts directly to prevent amyloid-beta42 accumulation. In the other, graphene oxide acts indirectly by a (currently unknown) mechanism, in which specific genes for stress response are activated. This increases the cell’s ability to handle misfolded proteins and oxidative stress.

  How to treat Alzheimer’s patients is still a question for the future. But according to the research group at Chalmers, graphene oxide holds great potential for future research in the field of neurodegenerative diseases. The research group has already been able to show that treatment with graphene oxide also reduces the toxic effects of protein aggregates specific to Huntington’s disease in a yeast model.

  “The next step is to investigate whether it is possible to develop a drug-delivery system based on graphene oxide for Alzheimer’s disease.” says Chen. “We also want to test whether graphene oxide has beneficial effects in additional models of neurodegenerative diseases, such as Parkinson’s disease.”

  This story is adapted from material from Chalmers University of Technology, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 04, 2023

• Materials Today -- News New ions prove effective for new carbon-capture technique

  New ions can facilitate carbon capture. Photo: Dravid lab/Northwestern University.

  Even as the world slowly begins to decarbonize its industrial processes, achieving lower concentrations of atmospheric carbon requires technologies that can remove existing carbon dioxide (CO₂) from the atmosphere – rather than just prevent the creation of it.

  Typical carbon capture takes CO₂ directly from the source of a carbon-intensive process. Ambient carbon capture, or direct air capture (DAC), on the other hand, can take carbon out of typical environmental conditions and serves as another weapon in the battle against climate change. It is set to become even more important as the world’s reliance on fossil fuels begins to decrease and, with it, the need for point-of-source carbon capture.

  Now, researchers at Northwestern University have investigated a novel approach to capturing carbon from ambient environmental conditions. They looked at the relationship between water and CO₂ in the ‘moisture-swing technique, which captures CO₂ at low humidities and releases it at high humidities. This approach incorporates innovative kinetic methodologies and a diversity of ions, allowing carbon removal from virtually anywhere. The researchers report their findings in a paper in Environmental Science & Technology.

  “We are not only expanding and optimizing the choice of ions for carbon capture, but also helping unravel the fundamental underpinnings of complex fluid-surface interactions,” said Vinayak Dravid, a senior author of the paper. “This work advances our collective understanding of DAC, and our data and analyses provide a strong impetus to the community, for theorists and experimentalists alike, to further improve carbon capture under practical conditions.”

  Dravid is a professor of materials science and engineering in Northwestern’s McCormick School of Engineering and director of global initiatives at the International Institute for Nanotechnology. PhD students, John Hegarty and Benjamin Shindel, were the paper’s co-first authors.

  According to Shindel, the idea behind the paper came from a desire to use ambient environmental conditions to facilitate the reaction. “We liked moisture-swing carbon capture because it doesn't have a defined energy cost,” he said. “Even though there’s some amount of energy required to humidify a volume of air, ideally you could get humidity ‘for free,’ energetically, by relying on an environment that has natural dry and wet reservoirs of air close together.”

  The group also expanded the number of ions used to make the reaction possible. “Not only have we doubled the number of ions that exhibit the desired humidity-dependent carbon capture, we have also discovered the highest-performing systems yet,” said Hegarty.

  In recent years, moisture-swing capture has taken off. Traditional carbon capture methods use sorbents to capture CO₂ at point-of-source locations, and then use heat or generated vacuums to release the CO₂ from the sorbent. But this comes with a high-energy cost.

  “Traditional carbon capture holds onto CO₂ tightly, which means it takes significant energy to release it and reuse it,” Hegarty said.

  It also doesn’t work everywhere. Agriculture, concrete and steel manufacturers, for example, are major contributors to emissions but have large footprints that make it impossible to capture carbon at a single source.

  Another senior author, chemistry professor Omar Farha, has experience at developing metal-oxide framework (MOF) structures for diverse applications, including CO₂ capture and sequestration.

  “DAC is a complex and multifaceted problem that requires an interdisciplinary approach,” Farha said. “What I appreciate about this work is the detailed and careful measurements of complex parameters. Any proposed mechanism must explain these intricate observations."

  In the past, researchers have zeroed in on carbonate and phosphate ions to facilitate moisture-swing capture and have specific hypotheses relating to why these specific ions are effective. But Dravid’s team wanted to test a wider breadth of ions to see which were the most effective. Overall, they found ions with the highest valency – mostly phosphates – were most effective and they began going down a list of polyvalent ions, ruling out some, as well as finding new ions that worked for this application, including silicate and borate.

  The team believes that future experiments, coupled with computational modeling, will help better explain why certain ions are more effective than others.

  There are already companies working to commercialize DAC, using carbon credits to incentivize companies to offset their emissions. Many are capturing carbon that would already have been captured through activities such as modified agricultural practices, whereas this approach unambiguously sequesters CO₂ directly from the atmosphere, where it could then be concentrated and ultimately stored or reused.

  Dravid’s team plans to integrate such CO₂-capturing materials with their previous porous sponge platform, which has been developed to remove environmental toxins including oil, phosphates and microplastics.

  This story is adapted from material from Northwestern University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

• Materials Today -- News X-ray laser captures the sound of crystals

  Soundwaves propagating in a diamond crystal, captured with the new X-ray technique. Image: Theodor S. Holstad et al./DTU.

  Solid crystalline materials – such as metals, ceramics, rock and bone – are notoriously difficult to model. They are made up of grains, domains and defects and are exposed to many competing forces that exert their influence on several levels. To model such materials, scientists have utilized highly specialized X-rays that can characterize materials at a resolution as low as 100nm.

  Resolution, however, is not the only important criteria. There is also the fact that what is happening in these materials occurs over time, but up to now scientists have only ben able to follow these processes over time periods of milliseconds to seconds. Inside crystals, though, some things happen very fast, like when they change shape or transfer heat. These processes are related to how the atoms in the crystals are arranged and move, and often happen in microseconds – sometimes even in nano- or picoseconds (one billionth or one trillionth of a second, respectively).

  This is the case with sound waves travelling through a crystalline material, which happens in less than a millisecond. Now, in a paper in the Proceedings of the National Academy of Sciences, researchers from Denmark and the US report capturing images of soundwaves traveling through a 1mm diamond sample.

  “We want to see these changes in 3D, but until now, it couldn’t be done fast enough or without damaging the crystals,” explains Henning Friis Poulsen, a professor in the Department of Physics at the Technical University of Denmark (DTU). “Our new technology can do it faster and non-invasively and will work for many crystals.

  “To do imaging at the speed of sound, it was necessary to build an entirely new microscope at the end of a 3km-long X-ray free-electron laser (XFEL). It is not a given that you’ll succeed when aiming a 3km-long X-ray source through multiple lenses and onto a sample that is 1mm across, while you hope to see a soundwave that only exists for a millionth of a second. Our hair-thin X-ray and optical laser beams had to meet on the millimeter-sized single-crystal diamond sample with a better timing accuracy than a nanosecond before the first data could be acquired. But we did it, and I believe these results will inspire a plethora of new research.”

  Co-author Theodor Holstad from DTU says that their approach could apply to all types of crystalline materials. “With this setup, we can investigate a wide range of ultrafast structural phenomena that have so far been beyond the reach of science. Visualizing structural processes on a timescale of less than a microsecond is relevant for solid-state physics, materials science and geoscience. For example, when you want to understand processes in meta-materials, photonic crystals, thermoelectric materials or even soft materials such as perylene and hybrid perovskites. Finally, it may be useful in geoscience to test seismological models of how sound travels in planetary materials.”

  The researchers took snapshots of the soundwaves with timesteps as small as just a few picoseconds and then edited those snapshots into small films. This allowed them to capture movies of different types of sound waves travelling and reflecting off the surface of a crystal and of dispersion (the wave spreading out over time) and attenuation (weakening of the wave) over microsecond timescales.

  Finally, they demonstrated that just a single X-ray pulse less than a thousandth of a nanosecond long was sufficient for imaging, opening the door to visualizing stochastic and irreversible processes in real-time on timescales of microseconds or less.

  This story is adapted from material from the Technical University of Denmark, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 03, 2023

• Materials Today -- News Conditions just right for spin defects in silicon carbide

  An artistic representation of spin defects in silicon carbide. Image: Emmanuel Gygi. With permission, a component of the figure is adapted from Christoph Dellago and Peter G. Bolhuis, Adv. Poly. Sci., Springer (2008).

  A computational study by researchers led by Giulia Galli at the University of Chicago’s Pritzker School of Molecular Engineering has predicted the conditions necessary for creating specific spin defects in silicon carbide. These findings, reported in a paper in Nature Communications, represent an important step towards identifying parameters for fabricating spin defects useful for quantum technologies.

  Electronic spin defects in semiconductors and insulators are rich platforms for quantum computing, sensing and communication applications. Defects are impurities and/or misplaced atoms in a solid and the electrons associated with these atomic defects carry a spin. This quantum mechanical property can be used to provide a controllable qubit, the basic unit of operation in quantum technologies.

  Yet the synthesis of these spin defects, typically achieved experimentally by implantation and annealing processes, is not yet well understood and, importantly, cannot yet be fully optimized. In silicon carbide – an attractive host material for spin qubits due to its industrial availability – different experiments have so far yielded different recommendations and outcomes for creating the desired spin defects.

  “There hasn’t yet been a clear strategy to engineer the formation of spin defects to the exact specifications we want, a capability that would be highly advantageous for advancing quantum technologies,” says Galli, a professor of molecular engineering and chemistry and corresponding author of the paper. “So, we embarked on a long computational journey to ask the following question: Can we understand how these defects form by carrying out comprehensive atomistic simulations?”

  Galli’s team – including Cunzhi Zhang, a postdoctoral researcher in Galli’s group, and Francois Gygi, a professor of computer science at the University of California, Davis – combined multiple computational techniques and algorithms to predict the formation of specific spin defects known as ‘divacancies’ in silicon carbide.

  “Divacancies are created by removing a silicon and a carbon atom sitting close together in a silicon carbide solid,” explains Zhang. “We know from previous experiments that these types of defects are promising platforms for sensing applications.”

  Quantum sensing could allow the detection of magnetic and electric fields and also reveal how complex chemical reactions occur, beyond what’s possible with today’s technologies. “To unlock quantum sensing capabilities in the solid-state, we first need to be able to create the right spin defects or qubits at the right location.” Galli says.

  To find a recipe for predicting the formation of particular spin defects, Galli and her team combined several techniques to help them look at the movements of atoms and charges when a defect forms as a function of temperature.

  “Typically, when a spin defect is created, other defects also appear and those may negatively interfere with the targeted sensing capabilities of the spin defect,” says Gygi, the main developer of the first-principles molecular dynamics code Qbox used in the team’s quantum simulations. “Being able to fully understand the complex mechanism of defect formation is very important.”

  The team coupled the Qbox code with other advanced sampling techniques developed within the Midwest Integrated Center for Computational Materials (MICCoM), a computational materials science center headquartered at Argonne National Laboratory and funded by the US Department of Energy. Galli and Gygi are both senior investigators at MICCoM.

  “Our combined techniques and multiple simulations revealed to us the specific conditions under which divacancy spin defects can be efficiently and controllably formed in silicon carbide,” Galli says. “In our calculations, we are letting the fundamental physics equations tell us what is happening inside the crystal structure when defects form.”

  The researchers expect that experimentalists will be interested in using their computational tools to engineer a variety of spin defects in silicon carbide and other semiconductors. However, they caution that generalizing their tool to predict a broader range of defect formation processes and defect arrays will require more work. “But the proof of principle we have provided is important – we showed that we can computationally determine some of the conditions required to create the desired spin defects” Galli says.

  Next, her team will continue working to expand their computational studies and speed up their algorithms. They also would like to expand their investigation to include a range of more realistic conditions. “Here, we’re only looking at samples in their bulk form, but in experimental samples there are surfaces, strain and also macroscopic defects,” Galli says. “We would like to include their presence in our future simulations and in particular understand how surfaces influence spin defect formation.”

  Although her team’s advance is based on computational studies, Galli says all their predictions are rooted in long-standing collaborations with experimentalists. “Without the ecosystem we work in, constantly talking with and partnering with experimentalists, this wouldn’t have happened.”

  This story is adapted from material from the University of Chicago, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.

October 02, 2023

• Wrocław University of Science and Technology We welcomed students from all over the world
  560 new foreign students officially commenced their studies at Wroclaw Tech today. During a special ceremony organised by the International Office, they were welcomed by, among others, the Vice-Rector for Cooperation, Prof. Dariusz Łydżba.

September 26, 2023

• Wrocław University of Science and Technology Inauguration of the academic year
  On Monday, October 2, at 10 in the aula of the university's main building (A-1) will officially begin the new academic year at Wrocław University of Science and Technology. A webcast of the event will be available on our Youtube channel.