Smart phonon control boosts efficiency in eco-friendly thermoelectric material

Researchers have significantly improved the efficiency of β-Zn₄Sb₃, a thermoelectric material that converts waste heat into electricity, without using rare or costly elements. This tellurium-free compound was studied using advanced neutron scattering techniques, revealing that tiny heat vibrations—called phonons—were being disrupted by “rattling” atoms within the crystal structure. This effect, known as phonon avoided crossing, greatly reduces heat transfer through the material, enhancing its energy-harvesting capabilities.

Thanks to this effect, the material’s thermal conductivity dropped to extremely low levels—great news for thermoelectric performance. Even better, the researchers found that the single-crystal version of this material also conducts electricity better than its polycrystalline counterpart, reaching a high power conversion efficiency of 1.4%.

These results show that smart phonon control can lead to high-performance, eco-friendly materials for converting heat into power.

In thermoelectric materials, avoided crossing refers to the interaction between propagating phonons and localized vibrational modes, where their energy dispersions repel each other rather than intersect. This phenomenon occurs under specific conditions, such as crystal symmetries or vibrational mode couplings.

However, when researchers developed the single-crystal β-Zn4Sb3, they observed an unexpected, avoided crossing, revealing unique phonon behavior that deviated from conventional thermoelectric materials.

The article explores the thermoelectric performance of single-crystalline β-Zn4Sb3, a tellurium-free material, by uncovering the microscopic mechanisms that lead to its ultralow lattice thermal conductivity (κL).

Using inelastic neutron scattering (INS), the researchers provide the first experimental observation of avoided crossing between longitudinal acoustic phonons and low-energy rattling modes. This interaction causes a significant reduction in phonon group velocity—from over 4000 m/s to about 591 m/s—and shortens phonon lifetimes to under 1 picosecond, both of which contribute to strongly suppressed heat transport.

The β-Zn4Sb3 single crystal achieves a κL of approximately 0.36 W/m·K in the 300–600 K range and a peak thermoelectric figure of merit (zT) of 1.0 at 623 K. Additionally, device-level testing shows a conversion efficiency (η) of 1.4% in a single-leg thermoelectric module—one of the highest reported for undoped Zn4Sb3.

Structural characterizations via TEM reveal a grain-boundary-free lattice with uniformly distributed moiré fringes, attributed to Zn concentration variations.

These nanoscale features further enhance phonon scattering without degrading electronic performance. Compared to polycrystalline samples, the single crystal exhibits significantly better electrical conductivity due to fewer defects and optimized carrier mobility.

“This discovery shows how heat flow can be engineered to design more efficient and sustainable energy technologies—without depending on scarce resources,” says Prof. Hsin-Jay Wu.

For more information: Advanced Science

Image: Phonon dispersion map single crystalline β-Zn4Sb3 of at 300 K, measured in the longitudinal scan along [hh0]. Credit: National Taiwan University

US scientists discover new 2D material that could be used in electrochemical energy tech

Nearly a decade ago, scientists predicted that boron atoms would bond too tightly to copper to form borophene—a promising, flexible, metallic 2D material with potential in electronics, energy, and catalysis. New research led by Rice University’s Boris Yakobson confirms this prediction, but in an unexpected way, offering fresh insights into the elusive material. Yakobson emphasized that since borophene remains on the edge of existence, every new discovery about it significantly advances our understanding of materials science, physics, and electronics.

“Our very first theoretical analysis warned that on copper, boron would bond too strongly, and even if borophene did form, it would be hopelessly attached to the substrate. Now, more than a decade later, it turns out we were right ⎯ and the result is not borophene, but something else entirely,” said Yakobson.

Researchers revealed that unlike systems such as graphene on copper, where atoms may diffuse into the substrate without forming a distinct alloy, the boron atoms in this case formed a defined 2D copper boride ⎯ a new compound with a distinct atomic structure. The finding sets the stage for further exploration of a relatively untapped class of 2D materials, according to researchers.

The research reveals that since the first realization of borophene on Ag(111), two-dimensional (2D) boron nanomaterials have attracted substantial interest because of their polymorphic diversity and potential for hosting solid-state quantum phenomena.

“Here, we use atomic-resolution scanning tunneling microscopy (STM) and field-emission resonance (FER) spectroscopy to elucidate the structure and properties of atomically thin boron phases grown on Cu(111). Specifically, FER spectroscopy reveals charge transfer and electronic states that strongly differ from the decoupled borophene phases observed on silver, suggesting that the deposition of boron on copper results in strong covalent bonding characteristic of a 2D copper boride,” said researchers.

Earlier, studies synthesized borophene on metals like silver and gold, but copper remained an open ⎯ and contested ⎯ case. Some studies also highlighted that the boron might form polymorphic borophene on copper, while others suggested it could phase-separate into borides or even nucleate into bulk crystals.

Researchers revealed that resolving these possibilities required a uniquely detailed investigation combining high-resolution imaging, spectroscopy and theoretical modeling.

Yakobson underlined that what experimentalists first saw were rich patterns of atomic resolution images and spectroscopy signatures, which required a lot of hard work of interpretation.

These efforts revealed a periodic zigzag superstructure and distinct electronic signatures, both of which deviated significantly from known borophene phases. A strong match between experimental data and theoretical simulations helped resolve a debate about the nature of the material that forms at the interface between the copper substrate and the near-vacuum environment of the growth chamber, according to a press release.

“2D copper boride is likely to be just one of many 2D metal borides that can be experimentally realized,” said Mark Hersam, Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University and a co-corresponding author on the study.

“We look forward to exploring this new family of 2D materials that have broad potential use in applications ranging from electrochemical energy storage to quantum information technology.”

For more information: Science Advances

Image: Calculated charge redistribution in copper boride (Cu8B14), where teal represents charge depletion and yellow represents charge accumulation.

These contacts let you see in the dark with your eyes closed

Scientists have developed innovative contact lenses that allow both humans and mice to see infrared light by converting it into visible colors—without the need for bulky equipment or batteries. These transparent lenses enable users to perceive both regular and infrared light simultaneously and can detect multiple infrared wavelengths at once. Remarkably, the lenses perform even better with eyes closed due to infrared light’s superior penetration. In tests, mice avoided infrared light, and humans could interpret flickering codes and light directions, showcasing the lenses’ potential for practical applications.

“Our research opens up the potential for non-invasive wearable devices to give people super-vision,” says senior author Tian Xue, a neuroscientist at the University of Science and Technology of China. “There are many potential applications right away for this material. For example, flickering infrared light could be used to transmit information in security, rescue, encryption or anti-counterfeiting settings.”

The lenses use specially engineered nanoparticles that absorb invisible infrared light and convert it into light our eyes can see, typically in the 400 to 700 nanometer range. More specifically, the technology targets near-infrared light, which lies just beyond human vision, in the 800 to 1600 nanometer range.

In earlier studies, the team showed these particles could give mice infrared vision when injected directly into the eye. This time, they’ve achieved similar results using a much less invasive approach—by building the particles right into soft contact lenses.

To create the contact lenses, the team combined the nanoparticles with flexible, non-toxic polymers that are used in standard soft contact lenses. After showing that the contact lenses were non-toxic, they tested their function in both humans and mice.

They found that contact lens-wearing mice displayed behaviors suggesting that they could see infrared wavelengths. For example, when the mice were given the choice of a dark box and an infrared-illuminated box, contact-wearing mice chose the dark box whereas contact-less mice showed no preference. The mice also showed physiological signals of infrared vision: the pupils of contact-wearing mice constricted in the presence of infrared light, and brain imaging revealed that infrared light caused their visual processing centers to light up.

In humans, the infrared contact lenses enabled participants to accurately detect flashing morse code-like signals and to perceive the direction of incoming infrared light. “It’s totally clear cut: without the contact lenses, the subject cannot see anything, but when they put them on, they can clearly see the flickering of the infrared light,” said Xue.

“We also found that when the subject closes their eyes, they’re even better able to receive this flickering information, because near-infrared light penetrates the eyelid more effectively than visible light, so there is less interference from visible light.”

An additional tweak to the contact lenses allows users to differentiate between different spectra of infrared light by engineering the nanoparticles to color-code different infrared wavelengths. For example, infrared wavelengths of 980 nm were converted to blue light, wavelengths of 808 nm were converted to green light, and wavelengths of 1,532 nm were converted to red light. In addition to enabling wearers to perceive more detail within the infrared spectrum, these color-coding nanoparticles could be modified to help color blind people see wavelengths that they would otherwise be unable to detect.

“By converting red visible light into something like green visible light, this technology could make the invisible visible for color blind people,” says Xue.

Because the contact lenses have limited ability to capture fine details (due to their close proximity to the retina, which causes the converted light particles to scatter), the team also developed a wearable glass system using the same nanoparticle technology, which enabled participants to perceive higher-resolution infrared information.

Currently, the contact lenses are only able to detect infrared radiation projected from an LED light source, but the researchers are working to increase the nanoparticles’ sensitivity so that they can detect lower levels of infrared light.

“In the future, by working together with materials scientists and optical experts, we hope to make a contact lens with more precise spatial resolution and higher sensitivity,” says Xue.

For more information: Cell

Robotic touch sensors are not just skin deep

Researchers at Northwestern University and Tel Aviv University have addressed a key challenge in developing affordable robotic touch by identifying a flaw in the materials used for robotic skin. They discovered that inexpensive silicone rubber composites form insulating layers on their surfaces, which block electrical contact between the sensing polymer and electrodes, leading to inaccurate readings. By eliminating this issue, the team has paved the way for low-cost robotic skins capable of mimicking human touch—enabling robots to detect curves and edges for more precise object handling.

“A lot of scientists misunderstand their sensor response because they lump together the behavior of the contacts with the behavior of the sensor material, resulting in inconsistent data,” Grayson said. “It turns out, if you are not aware of this problem, you can publish papers which no one can reproduce. Our work identifies the exact problem, quantifies its extent both microscopically and electrically, and gives a clear step-by-step trouble-shooting manual to fix the problem.”

The rubber that can be used for typical robotic skin, called an elastomer, is flexible, lightweight and inexpensive, and when electrically conducting fillers like carbon nanotubes are added to the mix, the resulting composite becomes an ideal candidate for a touch sensor, whose resistance changes locally when pressed. But to receive electrical signals, the sensors need to be electrically contacted, and the researchers detected a thin insulating layer ever-present in such composites which could drastically change the behavior of the contacts. Just by sanding down the ultrathin insulation layer, the team was able to achieve a much stronger electrical contact and calibrate the thickness of the insulating layer both electrically and microscopically.

“All interesting things happen at the interface,” said co-author and professor at Tel Aviv University Noa Lachman. “This publication not only shows the importance of sensor interfaces, but also the importance of working at the nexus between two different disciplines: materials science and electrical engineering. Materials experts suspected the presence of this insulating external layer in conductive polymer composites for years but couldn’t understand its electrical effects. Each of us has one piece of the puzzle, but only together can we get the whole picture.”

Robotics in particular can be tricky in part because it requires so many types of expertise. The polymer materials scientist designing the functional electronic material for a robot, for example, does not have the same training and skills as the electrical engineer whose electronics will process the sensor signals. Grayson said the “contact preparation” challenge was precisely where the conversation about this research began.

“That’s why our collaboration with Tel Aviv is essential – they know the materials science that we don’t know,” Grayson said. “We rely on them to prepare the materials we are studying, then we take and study the material before turning around to help the Tel Aviv materials scientists characterize their materials better.”

Producing new materials — and then reproducing them — requires consistency across many different variables that are often difficult or even impossible to control. In exposing the question of reproducibility in much of the literature on touch sensing, Grayson challenges the research community to hold itself to a higher standard with the quality check described in the paper. As awareness of this problem spreads among researchers, new publications can be more rigorously relied upon to advance the field with new capabilities.

For more information: Journal of Advanced Electronic Materials

Machine learning powers new approach to detecting soil contaminants

Researchers at Rice University and Baylor College of Medicine have developed a novel method to detect hazardous soil pollutants, including previously unstudied compounds, using a combination of light-based imaging, theoretical predictions of molecular light signatures, and machine learning algorithms. This technique enables the identification of toxic substances like polycyclic aromatic hydrocarbons (PAHs) and their derivatives (PACs)—common combustion by-products linked to cancer and developmental issues—without the need for physical reference samples or advanced lab facilities, overcoming a major limitation in traditional soil contamination analysis.

“This method makes it possible to identify chemicals that have not yet been isolated experimentally,” said Naomi Halas, University Professor and the Stanley C. Moore Professor of Electrical and Computer Engineering at Rice.

The new method uses a light-based imaging technique known as surface-enhanced Raman spectroscopy, which analyzes how light interacts with molecules, tracking the unique patterns, or spectra, they emit. Spectra serve as “chemical fingerprints” for each compound. The technique is refined through the use of signature nanoshells designed to enhance relevant traits in the spectra.

Using density functional theory ⎯ a computational modeling technique that can predict how atoms and electrons behave in a molecule ⎯ the researchers calculated what the spectra of a whole range of PAHs and PACs look like based on the compounds’ molecular structure. This allowed them to generate a virtual library of “fingerprints” for PAHs and PACs.

Two complementary ML algorithms ⎯ characteristic peak extraction and characteristic peak similarity ⎯ were used to parse relevant spectral traits in real-world soil samples and match them to compounds mapped out in the virtual library of spectra.

“We are using PAHs in soil to illustrate this very important new strategy,” Halas said. “There are tens of thousands of PAH-derived chemicals and this approach ⎯ calculating their spectra and using machine learning to connect the theoretically calculated spectra to those observed in a sample ⎯ allows us to identify chemicals that we may not, or do not, have any experimental data for.”

The method addresses a critical gap in environmental monitoring, opening the door to identifying a much broader range of hazardous compounds ⎯ including those that have changed over time. This is especially important given that soil is a dynamic environment where chemicals are subject to transformations that can render them harder to detect.

Thomas Senftle, Rice’s William Marsh Rice Trustee Associate Professor of Chemical and Biomolecular Engineering, compared the process to using facial recognition in order to find an individual in a crowd.

“You can imagine we have a picture of a person when they’re a teenager, but now they’re in their 30s,” Senftle said. “In my group what we do is, on the theory side, we can predict what the picture will look like.”

The researchers tested the method on soil from a restored watershed and natural area using both artificially contaminated samples and a control sample. Results showed the new approach reliably picked out even minute traces of PAHs using a simpler and faster process than conventional techniques.

“This method can identify lesser-known and largely unstudied PAH and PAC pollutant molecules,” said Oara Neumann, a Rice research scientist who is a co-author on the study.

In the future, the method could enable on-site field testing by integrating the ML algorithms and theoretical spectral library with portable Raman devices into a mobile system, making it easier for farmers, communities and environmental agencies to test soil for hazardous compounds without needing to send samples to specialized labs and wait days for results.

Ankit Patel, assistant professor of electrical and computer engineering at Rice and assistant professor of neuroscience at BCM, is a corresponding author on the study alongside Halas.

Other Rice co-authors include computer science doctoral alum Yilong Ju; doctoral students Sarah Denison, Peixuan Jin and Andres Sanchez-Alvarado; Peter Nordlander, the Wiess Chair in Physics and Astronomy and professor of electrical and computer engineering and materials science and nanoengineering; and Pedro Alvarez, the George R. Brown Professor of Civil and Environmental Engineering.

For more information: Proceedings of the National Academy of Sciences

Image: Naomi Halas and Ankit Patel

Tapping a new toolbox, engineers buck tradition in high-performing heat exchanger

Engineers at the University of Wisconsin–Madison have developed a high-performance, twisty high-temperature heat exchanger using a combination of topology optimization and advanced 3D metal printing. This innovative design significantly outperforms traditional straight-channel heat exchangers in terms of heat transfer, power density, and overall effectiveness. These heat exchangers are critical in industries such as aerospace, power generation, and aviation, where efficient heat dissipation is essential.

“Traditionally, heat exchangers flow hot fluid and cold fluid through straight pipes, mainly because straight pipes are easy to manufacture,” says Xiaoping Qian, a professor of mechanical engineering at UW–Madison. “But straight pipes are not necessarily the best geometry for transferring heat between hot and cold fluids.”

Additive manufacturing enables researchers to create structures with complex geometries that can yield more efficient heat exchangers. Given this design freedom, Qian set out to discover a design for the hot and cold fluid channels inside a heat exchanger that would maximize heat transfer.

He harnessed his expertise in topology optimization, a computational design approach used to study the distribution of materials in a structure to achieve certain design goals. He also incorporated a patented technique, called projected undercut perimeter, that considers manufacturability constraints for the overall design.

With an optimized design in hand, Qian worked with colleague Dan Thoma, a professor of materials science and engineering at UW–Madison, who led the 3D printing of the heat exchanger using a metal additive manufacturing technique called laser powder bed fusion.

From the outside, the optimized heat exchanger looks identical to a traditional version with a straight channel design—but their internal core designs are strikingly different. The optimized design has intertwining hot and cold fluid channels with intricate geometries and complex surface features. These complex geometric features guide fluid flow in a twisting path that enhances the heat transfer.

Collaborator Mark Anderson, a professor of mechanical engineering at UW–Madison, conducted thermal-hydraulic tests on the optimized heat exchanger and a traditional heat exchanger to compare their performance.

The optimized design was not only more effective in transferring heat but also achieved a 27% higher power density than the traditional heat exchanger. That higher power density enables a heat exchanger to be lighter and more compact—useful attributes for aerospace and aviation applications.

While previous research has used topology optimization to study two-fluid heat exchanger designs, Qian says this work is the first to harness topology optimization and impose manufacturability constraints to ensure the design can be built and tested.

“Optimizing design on the computer is one thing, but to actually make and test it is a very different thing,” Qian says.

“It’s exciting that our optimization method worked. We were able to actually manufacture our heat exchanger design. And, through experimental testing, we demonstrated the performance enhancement of our optimized design. The excellent work performed by the students, postdoctoral researchers and scientists in the three research groups made this advance possible.”

Sicheng Sun, a recent Ph.D. graduate from Qian’s research group, is the first author on the paper. Additional co-authors include Tiago Augusto Moreira, Behzad Rankouhi, Xinyi Yu and Ian Jentz, all from UW–Madison.

The researchers patented their projected undercut perimeter technique through the Wisconsin Alumni Research Foundation.

For more information: International Journal of Heat and Mass Transfer.

Image: A rendering of a topologically optimized unit cell for a heat exchanger core. The optimized design has hot and cold fluid channels with intricate geometries and complex surface features.

Researchers uncover why cracks in materials break their symmetry while spreading

All materials, including those in our bodies and the structures around us, contain tiny imperfections like cracks, which can sometimes spread suddenly and dangerously—but also form fascinating patterns. Physicists have long struggled to explain why these cracks often branch unpredictably and slow down. However, two recent studies from the Weizmann Institute of Science have revealed that despite their chaotic appearance, crack propagation follows specific physical parameters that govern their behavior and explain the emergence of asymmetrical patterns.

Decades of controlled experiments in material failure have shown that even when a perfectly symmetrical crack is created under tensile forces, it spontaneously loses symmetry as it propagates, veering off course and moving more slowly than expected.

“These observations are the exact opposite of what we would expect based on theoretical calculations, which predict that even if we introduce a small obstacle in the path of a symmetrical crack under tension, the crack should return to a smooth, symmetrical trajectory,” says Prof. Eran Bouchbinder.

“Given the experimental evidence, we assumed that there must be missing links—overlooked physical properties that could account for the observed behavior.”

In one of the two studies led by Dr. Yuri Lubomirsky, then a doctoral student in Bouchbinder’s group in Weizmann’s Chemical and Biological Physics Department, the researchers used a computer model to simulate the propagation of cracks in three-dimensional materials.

“To understand crack propagation, we focused on the crack tip—the point where the material transitions from intact to fractured,” explains Lubomirsky. “While moderate conditions prevail throughout most of the material most of the time—meaning its behavior can often be understood by averaging its properties—the crack tip is governed by extreme conditions.

“Physical quantities such as force, temperature and velocity are so large there that they can be mathematically treated as approaching infinity, and the usual physical rules no longer apply. We postulated that the crack tip might reveal the hidden properties that explain asymmetrical crack propagation.”

The researchers’ arduous seven-year search for these missing physical properties was at times frustrating. “Ultimately, the breakthrough came from introducing significant disorder into the simulations—a factor previously overlooked in dynamic theories of material failure.

“We ran numerous simulations using advanced computing capabilities and observed that the crack initially moves straight until it reaches a point where it splits locally and then changes direction,” Bouchbinder says.

“The challenge was to extract from the vast amount of data the basic principle explaining why the crack branches out and deviates from a smooth, symmetrical path. One day, I asked Yuri to cross-reference two graphs, and that’s when it clicked: The intrinsic disorder of real-world materials, combined with the extreme conditions at the crack tip, turned out to be the missing link.”

The laws of physics explain the behavior of uniform materials fairly well, but most materials in the world are not truly uniform. Glass, for example, appears smooth and homogeneous, but a closer look at its particles and the connections between them reveals a structure lacking consistent order. This means that the internal forces acting within glass vary from one region to another.

Until now, engineers and scientists trying to understand fracture dynamics had relied on averaged material properties and thus failed to explain why cracks break symmetry. Bouchbinder and Lubomirsky realized that the answer lies in the extent of internal disorder—that is, how much the material’s strength varies from place to place.

The researchers applied varying fracture forces to their computer model and studied the relationship between crack propagation and material disorder. They observed that when fracture forces were weak, cracks propagated symmetrically without branching and were largely unaffected by disorder.

However, when fracture forces were moderate, cracks became sensitive to disorder: When the crack tip reached a weaker region, local instabilities developed, causing the crack to split locally instead of continuing in a straight line. These local branches competed with each other—one branch would stall while the other would continue as the main crack, often changing direction.

Retrospective examination of these regions revealed microcracks where the secondary branches had been arrested. In other words, in this regime the extent of branching depended directly on the degree of disorder.

Finally, when fracture forces exceeded a critical threshold, the crack no longer halted at points of instability but split into entirely separate branches that widened and penetrated deeper into the material. In this high-force regime, disorder once again played a minor role.

The deviation of cracks from their symmetry axis and the formation of branches come at an energetic cost: A larger amount of material is broken, and the crack’s velocity decreases relative to the speed it would have reached had it remained smooth and symmetrical.

Another phenomenon commonly seen in cracks—also linked to symmetry breaking—is the formation of steps composed of two interacting fracture surfaces. In a follow-up study the researchers investigated how this pattern forms.

They found that step formation depends not only on the degree of internal disorder but also on external tensile forces’ slight deviations from perfect symmetry. In addition to the tensile forces that open the crack, there are almost always perpendicular forces causing the crack’s faces to slide past each other in a rotational motion.

Incorporating both types of force and the internal disorder into their mathematical model, the scientists succeeded in predicting and explaining the emergence of the step pattern.

“These discoveries provide a physical and mathematical framework for understanding material failure through crack dynamics that we encounter in everyday life,” says Bouchbinder.

Lubomirsky adds, “Our findings could also help in designing materials that are more resilient to catastrophic cracking. We show that increasing disorder can slow crack propagation—an insight that could have significant implications for the design of structures and physical systems.

“Natural materials such as bones and teeth have evolved to resist failure, and it’s possible that their internal disorder is one of the key factors behind their resilience. This is where our findings also shed new light on the workings of nature.”

For more information: Nature Communications

Image: The crack driving force as a function of its propagation velocity in 2D and 3D, under different levels of disorder, and the emergence of a limiting crack velocity.

New spectroscopy technique extends device lifespan

High-resolution, full-color display devices like foldable smartphones and ultrathin televisions use organic light-emitting diodes (OLEDs) due to their flexibility, self-illumination, lightweight construction, ultra-thin profiles, high contrast ratios, and low-voltage operation. An OLED consists of multiple ultrathin organic film layers between two electrodes, each layer playing a specific role in the device’s operation. When voltage is applied, electrical charges accumulate and emit light at the interfaces between these layers. While this multilayer structure allows precise control of charge accumulation, transport, and light generation, it also leads to degradation of the organic layers over time, limiting the lifespan and efficiency of OLED devices.

Understanding how the electronic structure at these interfaces behaves during operation remains a significant challenge. To tackle this issue, Professor Takayuki Miyamae, together with Mr. Tatsuya Kaburagi and Dr. Kazunori Morimoto from Chiba University in Japan, employed a second-order nonlinear spectroscopic method known as sum-frequency generation (SFG). This technique enabled them to investigate the vibrational and electronic properties at the interfaces within operating OLEDs, offering new insights into their behavior under real-world conditions.

When voltage is applied to an OLED system, light is emitted via the recombination of charges at the organic interfaces. This alters the SFG output, allowing researchers to study how charge accumulates and what electronic structural changes occur at the interfaces under different operating conditions.

three different multilayer OLEDs with different types and combinations of organic layers were used. Electronic SFG (ESFG) spectroscopy was conducted on three OLED devices to examine spectral changes induced by the charge behavior and electronic structure at the interfaces. “We examined the differences in the electric field intensities inside the OLED devices based on the applied voltage dependence of the ESFG spectra. This clarifies the role of field strength differences that affect the ease of internal charge flow and the light emission characteristics for the first time,” explains Prof. Miyamae about the team’s study.

ESFG spectral bands corresponding to each organic layer were identified by comparing the absorption spectra and layer configurations among the three OLED devices. The researchers observed changes in spectral signal intensities when applying voltages to the OLED devices, which were related to the changes in the electric field and charge behavior inside the OLEDs.

Upon voltage application, the spectral signal intensity increased at the absorption band of the hole transport material (positive charge carriers inside the OLED), and signal intensity decreased at the absorption band of the light-emitting layer. This shows that internal charge flow across the organic layers within the OLEDs is different, leading to changes in spectra.

The team also applied square-wave pulse voltages on these devices to study how electric fields formed within these devices varied with time. They found that adding BAlq (a material used for electron transport in OLEDs) changes the position where the light is emitted in OLEDs. This shift in emission affects both the color and shape of the emitted light and how efficiently the device converts electricity into light.

“ESFG technique represents a novel, highly effective, nondestructive, and non-invasive spectroscopic approach for examining the electric field generation caused by injected charges in solid-state thin-film devices,” notes Prof. Miyamae about this innovative research work.

With this technique, material scientists can now design OLEDs with improved device lifetimes, energy efficiency, and cost reductions, eventually increasing the use of ultrathin organic devices in our everyday lives. “Moreover, this research can greatly shorten and rationalize materials development research, which now performs trial-and-error processes and long periods of degradation verification to assess device efficiency and lifetime,” adds Prof. Miyamae.

For more information: Journal of Materials Chemistry C

New material gives copper superalloy-like strength

Researchers from the U.S. Army Research Laboratory and Lehigh University have developed a nanostructured copper alloy (Cu-Ta-Li) with exceptional thermal stability and mechanical strength, potentially redefining high-temperature materials for aerospace, defense, and industrial applications. This groundbreaking alloy is one of the most resilient copper-based materials ever created. The research, supported by a $25 million cooperative agreement and Lehigh’s Presidential Nano-Human Interfaces Initiative, highlights the decade-long partnership between Lehigh and ARL in advancing materials science.

“This is cutting-edge science, developing a new material that uniquely combines copper’s excellent conductivity with strength and durability on the scale of nickel-based superalloys,” said Martin Harmer, the Alcoa Foundation Professor Emeritus of Materials Science and Engineering at Lehigh and a co-author of the study. “It provides industry and the military with the foundation to create new materials for hypersonics and high performance turbine engines.”

The ARL and Lehigh researchers collaborated with scientists from Arizona State University and Louisiana State University to develop the alloy, which can withstand extreme heat without significant degradation.

This and other innovative alloys will continue to be studied in Lehigh’s newly outfitted high-tech research labs, the Nanoalloy Lab and Nanoceramics Lab, which include high-pressure torsion systems, nanoindentation equipment and specialized high-temperature furnaces.

The breakthrough comes from the formation of Cu₃Li precipitates, stabilized by a Ta-rich atomic bilayer complexion, a concept pioneered by the Lehigh researchers. Unlike typical grain boundaries that migrate over time at high temperatures, this complexion acts as a structural stabilizer, maintaining the nanocrystalline structure, preventing grain growth and dramatically improving high-temperature performance.

The alloy holds its shape under extreme, long-term thermal exposure and mechanical stress, resisting deformation even near its melting point, noted Patrick Cantwell, a research scientist at Lehigh University and co-author of the study.

By merging the high-temperature resilience of nickel-based superalloys with copper — which is known for exceptional conductivity — the material paves the way for next-generation applications, including heat exchangers, advanced propulsion systems and thermal management solutions for cutting-edge missile and hypersonic technologies.

This new Cu-Ta-Li alloy offers a balance of properties not found in existing materials:

  • Nickel-based superalloys (used in jet engines) are extremely strong but lack the high thermal conductivity of copper alloys.
  • Tungsten-based alloys are highly heat-resistant but dense and difficult to manufacture.
  • This Cu-Ta-Li alloy combines copper’s exceptional heat and electrical conductivity while remaining strong and stable at extreme temperatures.
  • While not a direct replacement for traditional superalloys in ultra-high temperature applications, it has the potential to complement them in next-generation engineering solutions.

The team synthesized the alloy using powder metallurgy and high-energy cryogenic milling, ensuring a fine-scale nanostructure. They then subjected it to:

  • 10,000 hours (over a year) of annealing at 800°C, testing its long-term stability.
  • Advanced microscopy techniques, revealing the Cu₃Li precipitate structure.
  • Creep resistance experiments, confirming its durability under extreme conditions.
  • Computational modeling using density functional theory (DFT), which validated the stabilizing role of the Ta bilayer complexion.

A project such as this takes years of careful work and collaboration, said Christopher Marvel ’12 ’16 Ph.D., an author of the paper and professor of mechanical engineering at Louisiana State University.

“Lehigh has such a strong reputation for electron microscopy, and that is what interested the ARL in working with us on this material. It was our microscopy that was really key to understanding the material,” said Marvel, who helped lead that portion of the research over a six-year period. “The Lehigh faculty have worked on many high-level research projects over the years, and they’ve all taught me different things that I apply now as an academic.”

The ARL was awarded a U.S. patent (US 11,975,385 B2) for the alloy, highlighting its strategic significance, particularly in defense applications like military heat exchangers, propulsion systems and hypersonic vehicles.

Further research will include direct measurements of the alloy’s thermal conductivity compared to nickel-based alternatives, work to ready it for potential applications, and the development of other high-temperature alloys following a similar design strategy.

For more information: Science

Image: This groundbreaking nanostructured copper alloy that could redefine high-temperature materials for aerospace, defense and industrial applications.

LIFT launches Advanced Metallic Production and Processing (AMPP)

LIFT, a Department of Defense-supported national advanced materials manufacturing innovation institute, has opened the Advanced Metallic Production and Processing (AMPP) Center in Detroit’s Corktown district. This facility will enhance the U.S. industrial base by accelerating the design, development, and deployment of novel metallic materials, addressing a critical gap in defense manufacturing. By producing metals across all alloy classes and processing them into high-quality feedstocks, AMPP will expedite materials development, particularly for additive manufacturing, ensuring manufacturers have access to essential materials for next-generation defense and commercial technologies.

Advanced materials are critical across industries. According to a recent report from Siemens Digital Industries Software, ”Innovation is key to the survival and growth of all companies. Product and materials inno­vation are closely linked, with product innovation relying on materials innovation by almost 70 percent. Therefore, it’s clear that developing new materials or innovative applica­tions of existing materials are of paramount importance for the manufacturing industry.”

This capability de-risks materials development investment for our domestic manufacturers and unlocks faster time to market and overall reduced cost of development.

A National Collaboration to Drive Innovation
The AMPP Center will serve as a hub for collaboration between LIFT’s nearly 400-member network and key industry stakeholders, including:
– Original Equipment Manufacturers
– Systems Manufacturers
– Materials Producers & Developers
– Application Developers & Part Manufacturers
– Academia & Startups

LIFT’s new Advanced Metallics Production and Processing Center exemplifies the mission of the Department of Defense’s Manufacturing Innovation Institutes: to close critical advanced manufacturing gaps in the U.S. defense industrial base and ensure we remain the strongest and most lethal force in the world,” said Keith DeVries, Director of Manufacturing Technology (ManTech) under the Office of the Under Secretary of Defense for Research and Engineering (OUSD(R&E)).

Advancing American Manufacturing & Security
Nigel Francis, CEO & Executive Director of LIFT, emphasized the importance of AMPP in maintaining America’s competitive edge:
“The pace of advanced manufacturing innovation is accelerating, and the development of novel materials is crucial to keeping the U.S. ahead of global competitors. With AMPP, we can now rapidly move new materials from concept to prototype, feasibility testing, and full-scale production—all within our borders. This capability is a game-changer for both our warfighters and manufacturers across industries.”

“A decade ago, we welcomed LIFT to Detroit to research and develop the next generation of advanced materials for commercial and defense uses,” said Mike Duggan, Mayor, City of Detroit. “This expansion into the production and processing of these materials demonstrates the success of their work and is a great example of how Detroit is very much a national center for innovation.”

Key Capabilities of the AMPP Center
– Low to Medium Volume Material Production
– Accelerated Material Delivery & Availability
– Toll Processing & Contract Manufacturing
– Domestic Production Through a Nonprofit Public-Private Partnership

Bringing Next-Generation Materials to Market and Scaling-Up Additive Manufacturing

As LIFT celebrates its 11th year as a national manufacturing innovation institute, it continues to expand its impact and technologies across the country, recently opening a facility in Puerto Rico and exploring new expansion opportunities.

For more information: LIFT

Exploring quantum materials for a new generation of technology

Today’s technology, from computer chips to camera image sensors, relies heavily on silicon semiconductors, which have been shrinking for decades. However, physical limitations will soon halt further advancements. Consequently, scientists and engineers are developing a new generation of technology based on quantum mechanics. Electrons in “quantum materials” exhibit unique behaviors, such as magnetism and superconductivity, which are crucial for future quantum technologies.

“Our piece of the puzzle is understanding how these materials function as a prerequisite for using them in engineering devices,” said Mark Dean, a physicist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and leader of the Dynamics and Control Group in Brookhaven’s Condensed Matter Physics and Materials Science Department.

Dean characterizes quantum materials using a technique called resonant inelastic X-ray scattering, or RIXS. RIXS is particularly suited for probing samples as thin as one atomic layer and material states that change very rapidly. And with recent technological developments, researchers expect this technique to enable studies that were unthinkable only five years ago.

This progress gave Dean and three colleagues — Matteo Mitrano, Steven Johnston, and Young-June Kim — the impetus to chart where the field is going as a whole. So, they summarized the technique’s state of the art and how they expect the field to progress in a Perspective paper.

For more information: Physical Review X

Image: The graphic illustrates an ultrabright X-ray striking a quantum material’s electrons (gray circles) and scattering off the sample. In this example, the X-ray’s energy change will provide insight into an electron property called spin, represented by the arrows. (Brad Baxley/Part to Whole LLC)

Scientists observe exotic quantum phase once thought impossible

Rice University researchers have directly observed a superradiant phase transition (SRPT), a quantum phenomenon predicted over 50 years ago, which could revolutionize quantum computing, communication, and sensing. This occurs when quantum particles fluctuate collectively without external triggers, forming a new state of matter. The discovery was made in a crystal of erbium, iron, and oxygen, cooled to minus 457°F and exposed to a magnetic field of up to 7 tesla.

“Originally, the SRPT was proposed as arising from interactions between quantum vacuum fluctuations — quantum light fields naturally existing even in completely empty space — and matter fluctuations,” said Dasom Kim, a Rice doctoral student in the Applied Physics Graduate Program who is a lead author on the study. “However, in our work, we realized this transition by coupling two distinct magnetic subsystems — the spin fluctuations of iron ions and of erbium ions within the crystal.”

Spin describes the magnetic poles of electrons or other particles and can be envisioned as a tiny arrow attached to each particle, constantly twirling and pointing in a given direction. When spins align, they create magnetic patterns across a material. When the pattern of spins ripples across the material like a wave, the resulting collective excitation is known as a magnon.

Until now, whether or not an SRPT could actually take place was subject to debate as it runs against a limitation — called “no-go theorem” in theoretical physics — arising in light-based systems. By staging an SRPT in a magnetic crystal based on the interactions between two spin subsystems, the researchers were able to get around this barrier, creating a magnonic version of the phenomenon. Specifically, the iron ions’ magnons play the role traditionally attributed to vacuum fluctuations, and the erbium ions’ spins represent matter fluctuations.

Using advanced spectroscopic techniques, the researchers observed unmistakable signatures of an SRPT, with the energy signal of one spin mode vanishing and another showing a clear shift or kink. These spectral fingerprints match exactly what theory predicts for entering the superradiant phase, giving the team high confidence that they had indeed coaxed the long-sought state into being.

“We established an ultrastrong coupling between these two spin systems and successfully observed a SRPT, overcoming previous experimental constraints,” Kim said.

Researchers are excited not just because a 50-year-old physics prediction has been confirmed but also because of what this could mean for quantum technology. Collective quantum states at the SRPT have unique properties that could be harnessed for next-generation quantum technologies.

“Near the quantum critical point of this transition, the system naturally stabilizes quantum-squeezed states — where quantum noise is drastically reduced — greatly enhancing measurement precision,” Kim said. “Overall, this insight could revolutionize quantum sensors and computing technologies, significantly advancing their fidelity, sensitivity and performance.”

Sohail Dasgupta, a graduate student at Rice working with Kaden Hazzard, associate professor of physics and astronomy, theoretically modeled the SRPT, building on a model developed by their collaborator and co-author Motoaki Bamba, a professor at Yokohama National University.

“Although the basic mathematical model was already laid out before by Motoaki, we needed to account for some of the specific magnetic properties of the material to obtain the precise results. When your theory matches the experimental data ⎯ which happens rather rarely ⎯ it is the best feeling for a scientist,” Dasgupta said.

Hazzard said the achievement shows that concepts from quantum optics can be translated into solid materials.

“This opens a new way to create and control phases of matter using ideas from cavity quantum electrodynamics,” Hazzard said.

Moreover, the crystal used in this study is one example of a broader class of materials, which means the research paves the way for exploring quantum phenomena in other materials with similarly interacting magnetic components.

For more information: Science Advances

Image: Dasom Kim (Photo by Jorge Vidal/Rice University)

Celera samples the first ever Analog IC completely designed by software

Celera, Alameda, Calif., the leader in fully automated, AI-enhanced analog design, is now sampling the first ever analog IC completely designed by an autonomous software platform.
Using Celera’s ChipHUB platform, the company improved engineering productivity by 10x, allowing the design of a high-performance buck (DC-to-DC) converter from specification to manufacturing release in a matter of days.

“This is a major milestone for Celera and an important breakthrough for our customers,” said Pat Brockett, Celera’s CEO. “Celera has demonstrated that end-to-end automated design of high-performance analog ICs can be done.”

“Using our patented digital twin Nesto technology, we enable our customers to achieve full custom analog IC design in days, at a fraction of the of the cost of current design methods,” said Alberto Viviani, Celera’s COO. “It’s very important to note that the resultant product designs are more than competitive with regard to die size (cost) and performance.”

Ramesh Giri, the head of product definition and applications at Celera highlighted a critical benefit to business managers – “Our design flow integrates an auto-generated behavioral model at the front-end that is tuned to actual silicon behavior. This allows system designers to do a comprehensive virtual bench road test, helping to reliably identify real-world system level issues at the front-end of the design process. This eliminates post-silicon fixes and enables faster time to market.”

“This first customer product is a state-of-the-art high voltage step down converter for industrial and automotive applications,” said Calum MacRae, CTO and founder at Celera. “Our Nesto technology simplifies analog IC design, enabling even non-IC designers to generate custom silicon. A huge benefit of our Nesto technology is that the same algorithm can be used to quickly produce whole families of buck converters in hours.”

Calum added, “Our IP is all in digital form. This allows us to train machine learning (ML) models, producing AI agents for analog design, layout, and modeling. The ability to generate large amounts of synthetic data positions Celera as the only company able to apply ML to analog design.”

“Celera’s patented technology will revolutionize the analog IC industry by making analog custom design available to all,” said Pat Brockett. “We are already engaged with major customers designing products for consumer, data center, wireless, industrial, solar and automotive applications. This is a real example where AI is changing a hundred-billion-dollar industry and we are proud to say Celera is leading that change.”

For more information:

Celera

https://www.celeratechnologies.com

 

 

Charging electric vehicles 5x faster in subfreezing temps

University of Michigan engineers developed a modified manufacturing process for electric vehicle batteries—using a stabilizing electrode coating and microscale channels—that could enable high ranges and fast charging in cold weather, solving problems that are turning potential EV buyers away.

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Strange behavior in ultra-thin materials

Researchers at the Hebrew University of Jerusalem, led by Ph.D. student Nofar Fridman and Prof. Yonathan Anahory, have discovered unexpected behavior in superconductivity within extremely thin materials. Superconductors, which allow electric current to flow without resistance, typically exhibit predictable changes when thinned. However, the team found surprising results when studying thin films of niobium diselenide (NbSe2), a layered superconducting material. Using advanced magnetic imaging techniques, they measured the material’s response to magnetic fields as its thickness decreased, revealing new insights into superconductivity at the nanoscale.

Typically, scientists expect the ability of a superconducting material to expel magnetic fields to become stronger as the material becomes thicker. Here, this length is gauged by a physical property called the Pearl length. This study confirmed that rule for samples thicker than ten atomic layers. However, when the films became extremely thin—just three to six layers (2-4 nm) —the researchers observed something unexpected: the Pearl length sharply increased and became thickness independent, breaking the expected pattern.

“Our findings reveal something completely unexpected that could be ubiquitous in superconducting materials,” explained Nofar Fridman, the Ph.D. student leading the study. “In very thin samples, superconductivity behaves differently from what we’ve known. It seems that below a certain thickness, superconductors host current mostly at their top and bottom surfaces, rather than throughout their volume. This finding opens up exciting new questions about superconductivity in ultra-thin materials.”

The team’s supervisor, Prof. Yonathan Anahory, emphasized the importance of their method, saying, “Our high-resolution magnetic imaging allowed us to see details that previous methods couldn’t detect. By finding this unique surface superconductivity, we’ve expanded our understanding of how superconducting materials behave at extremely small scales. This could have significant implications for future research and technologies.”

This discovery sheds new light on superconductivity in very thin films and challenges previously held theories. It also highlights how specialized measurement techniques can uncover surprising new physical phenomena, potentially opening avenues for innovative applications in quantum technology.

For more information: Nature Communications

Image: A schematic illustration of the experimental setup shows a scanning magnetic microscope positioned above two different samples. One sample exhibits only surface superconductivity, while the other displays conventional superconductivity.

SLAC fired the most intense submicron electron beam in history

Scientists at SLAC National Accelerator Laboratory have developed an ultrashort electron beam with five times the peak current of any previous beam, addressing a major challenge in particle accelerator and beam physics: generating high-power electron beams without compromising quality. This breakthrough opens new research possibilities in quantum chemistry, astrophysics, and materials science.

“Not only can we create such a powerful electron beam, but we’re also able to control the beam in ways that are customizable and on demand, which means we can probe a much wider range of physical and chemical phenomena than ever before,” said Claudio Emma, a staff scientist at the Department of Energy’s SLAC National Accelerator Laboratory, who is a researcher at SLAC’s Facility for Advanced Accelerator Experimental Tests (FACET-II) and a lead author on the new study.

One of the field’s longstanding goals has been to develop electron beams that are both extremely powerful and precisely controlled. Until now, increasing a beam’s power often meant degrading its quality, a tradeoff that has limited progress in many advanced experiments.

Traditionally, a microwave field is used to compress and focus the electron beam. The electrons within the field are staggered, so that those further back have more energy than those in the front. It’s sort of like runners staggered at the start of a track race, Emma explained. “We then send them around a bend, so the electrons in back catch up with electrons in front, and then at the end, you have a bunch of electrons together in a focused beam.”

The problem with this approach is that as they accelerate, electrons emit radiation and lose energy, so the quality of the beam deteriorates. That creates a tradeoff between beam energy and quality. “We can’t apply traditional methods to compress bunches of electrons at the submicron scale, while also preserving beam quality,” Emma said.

To solve this issue, SLAC researchers compressed billions of electrons into a length less than one micrometer using a laser-based shaping technique originally developed for X-ray free-electron lasers, such as SLAC’s Linac Coherent Light Source (LCLS). “The big advantage of using a laser is that we can apply an energy modulation that’s much more precise than what we can do with microwave fields,” Emma said.

But it’s not as simple as just shooting a few lasers down a tunnel. “We have a one-kilometer-long machine, and the laser interacts with the beam in the first 10 meters, so you have to get the shaping exactly right, then you have to transport the beam for another kilometer without losing this modulation, and you have to compress it,” Emma said. “So it wasn’t easy.”

After several months of testing and finessing their laser shaping technique, Emma and his team can now repeatedly produce high energy, femtosecond-duration, petawatt peak power electron beams that are about five times higher in current than what could previously be achieved.

This new beam will allow scientists to probe a whole series of natural phenomena, including testing hypotheses in quantum physics, materials science, and astrophysics.

In astrophysics, for example, this beam can be directed to a solid or gas target to create a filament similar to those seen in stars. “Scientists know that these filaments occur, but now we can test how they occur and evolve in the lab with a level of power we haven’t had before,” Emma said.

Fellow FACET-II researchers pounced on the more powerful beam and have already applied it to advancing plasma wakefield technology. Emma is particularly excited about the prospect of further compressing these beams to make attosecond light pulses, further enhancing LCLS’s current attosecond capabilities and driving even more pioneering science. “If you have the beam as a fast camera, then you also have a light pulse that’s very short, and now suddenly you have two complementary probes,” Emma explained. “That’s a unique capability and we can do a lot of things with that.”

Emma and his colleagues are excited about the prospects this new electron beam will bring. “We have a really exciting and interesting facility at FACET-II where people can come and do their experiments,” he said. “If you need an extreme beam, we have the tool for you, and let’s work together.”

For more information: Physical Review Letters

Image: At the heart of the new study is a laser heater undulator, a device that allows researchers to tightly control electron beams.

Chance discovery improves stability of bioelectronic material used in medical implants, computing and biosensors

A chance discovery by scientists from Rice University, University of Cambridge, and Stanford University has streamlined the production of PEDOT:PSS, a material widely used in medical research and computing. For over two decades, a chemical crosslinker was used to stabilize this conductive polymer in water. However, while experimenting with patterning techniques for biomedical optics, Stanford doctoral student Siddharth Doshi, collaborating with Rice’s Scott Keene, found that heating the material at a higher temperature without the crosslinker resulted in a stable sample, eliminating the need for the crosslinker.

“It was more of a serendipitous discovery because Siddharth was trying out processes very different to the standard recipe, but the samples still turned out fine,” Keene said. “We were like, ‘Wait! Really?’ This prompted us to look into why and how this worked.”

What Keene and his team found was that heating PEDOT:PSS beyond the usual threshold not only makes it stable without needing any crosslinker, but it also creates higher quality devices. This method could make bioelectronic devices easier and more reliable to manufacture with potential applications in neural implants, biosensors and next-generation computing systems.

PEDOT:PSS is a blend of two polymers: one that conducts electronic charge and does not dissolve in water and another that conducts ionic charge and is water-soluble. Because it conducts both types of charges, PEDOT:PSS bridges the gap between living tissue and technology.

“It allows you to essentially talk the language of the brain,” said Keene, who researches advanced materials for smaller, high-resolution electrodes capable of both recording and stimulating neural activity with precision.

The human nervous system relies on ions—charged particles like sodium and potassium—to transmit signals, while electronic devices work with electrons. A material that can handle both is crucial for neural implants and other bioelectronic devices that need to translate biological activity into readable data and send signals without damaging sensitive tissue.

In contrast, the higher heat stabilizes PEDOT:PSS by causing a phase change in the material. When heated beyond a certain temperature, the water-insoluble polymer reorganizes internally, pushing the water-soluble components to the surface, where they can be washed away. What remains is a thinner, purer and more stable conducting film.

“This method pretty much simplifies a lot of these problems that people have working with PEDOT:PSS,” Keene said. “It also essentially eliminates a potentially toxic chemical.”

Margaux Forner, a doctoral student at Cambridge who is a first author on the paper along with Doshi, said that heat-treated bioelectronic devices such as transistors, spinal cord stimulators and electrocorticography arrays — implanted grids or strips of neuroelectrodes used to record brain activity — were easier to fabricate, more reliable and equally high performing to those fabricated using the crosslinker.

“The devices made from heat-treated PEDOT:PSS proved to be robust in chronic in vivo experiments, maintaining stability for over 20 days postimplantation,” Forner said. “Notably, the film maintained excellent electrical performance when stretched, highlighting its potential for resilient bioelectronic devices both inside and outside the body.”

The finding may help explain why previous efforts to use PEDOT:PSS in long-term neural implants, including those by Neuralink, ran into stability issues. By making PEDOT:PSS more reliable, this discovery could help advance neurotechnology, including implants to restore movement after spinal cord injuries and interfaces that link the brain to external devices.

Beyond simplifying fabrication, the team found a way to pattern PEDOT:PSS into microscopic 3D structures — a breakthrough that could further improve bioelectronic devices. Using a high-precision femtosecond laser, the researchers can selectively heat sections of the material, creating custom textures that enhance how cells interact with the devices.

By eliminating the crosslinker, the research findings not only streamline the PEDOT:PSS fabrication process but also improve its performance. The new method produces a material with three times higher electrical conductivity and more consistent stability between batches — key advantages for medical applications.

The crosslinker worked by chemically bonding the two types of polymer strands in PEDOT:PSS together, creating an interconnected mesh. However, it still left some of the water-soluble strands exposed — a likely cause for the stability issues. Moreover, the crosslinker introduced variability and potential toxicity in the material.

This technique could be used to design neural interfaces that encourage better integration with surrounding tissue, improving signal quality and longevity.

Keene had also previously researched PEDOT:PSS in the context of neuromorphic memory devices used to accelerate artificial intelligence algorithms. Neuromorphic memory is a type or artificial memory that mimics how the brain retains information.

“It basically emulates the synaptic plasticity of your brain,” Keene said. “We can modify the connection between two terminals by controlling how conductive this material is; this is very similar to how your brain learns by strengthening or weakening synaptic connections between individual neurons.”

By unseating a long-standing assumption, the research not only made PEDOT:PSS easier to work with but also more powerful — a shift that could accelerate the development of safer, more effective neural implants and bioelectronic systems.

For more information: Rice University

Image: Implantable electrocorticography device (left) made using the heat treatment method (Photo courtesy of Margaux Forner); Rice University logo (right) patterned into PEDOT:PSS using a femtosecond laser

Scientists merge two “impossible” materials into new artificial structure

An international team led by Rutgers University-New Brunswick researchers has created a synthetic quantum structure by merging two lab-synthesized materials, previously thought impossible to combine. This exotic structure, developed through four years of experimentation, could provide new insights for quantum computing. The structure consists of distinct atomic layers: dysprosium titanate, used in nuclear reactors to trap radioactive materials and magnetic monopoles, and pyrochlore iridate, a magnetic semimetal known for its unique electronic, topological, and magnetic properties.

Individually, both materials are often considered “impossible” materials due to their unique properties that challenge conventional understanding of quantum physics.

The construction of the exotic sandwich structure sets the stage for scientific explorations in what is referred to as the interface, the area where the materials meet, in the atomic scale.

“This work provides a new way to design entirely new artificial two-dimensional quantum materials, with the potential to push quantum technologies and provide deeper insight into their fundamental properties in ways that were previously impossible,” said Jak Chakhalian, the Claud Lovelace Endowed Professor of Experimental Physics in the Department of Physics and Astronomy at the Rutgers School of Arts and Sciences and a principal investigator the study.

Chakhalian and his team are exploring a realm that follows the laws of quantum theory, a branch of physics that describes the behavior of matter and energy at the atomic and subatomic level. Central to quantum mechanics is the concept of wave-particle duality where quantum objects can possess both wave-like and particle-like properties – a foundational principle behind technologies such as lasers, magnetic resonance imaging (MRI) and transistors.

Chakhalian highly praised the efforts of three Rutgers students who made major contributions to the research: Michael Terilli and Tsung-Chi Wu, both doctoral students, and Dorothy Doughty, who graduated in 2024 and worked on the study as an undergraduate. In addition, Mikhail Kareev, who is a materials scientist working with Chakhalian, made a main contribution to the new synthesis method, as well as Fangdi Wen, a doctoral student who recently graduated from the Department of Physics and Astronomy.

Chakhalian said that creating the unique quantum sandwich was so technically challenging that the team had to build a new device to accomplish the feat.

The instrument, called Q-DiP, short for quantum phenomena discovery platform, was completed in 2023. Q-DiP incorporates an infrared laser heater with another laser which enables the construction of materials on an atomic level, layer by layer. The combination allows the scientists to explore the most intricate quantum properties of materials down to ultra cold temperatures near absolute zero.

“To the best of our knowledge, this probe is unique in the U.S. and represents a breakthrough as an instrumental advance,” Chakhalian said.

The half of the experimental sandwich that is dysprosium titanate, also known as spin ice, possesses special qualities. Tiny magnets inside, called spins, are arranged in a way that looks exactly like the pattern of water ice. The unique structure of the tiny magnets in spin ice allows them to emerge as special particles called magnetic monopoles.

A magnetic monopole is a particle that acts like a magnet, but with only one pole – either north or south, but not both. This object, predicted in 1931 by the Nobel prize winner Paul Dirac, does not exist in free form in the universe and yet inside spin ice it emerges as a result of the quantum mechanical interactions within the material.

On the other side of the sandwich, the semimetal pyrochlore iridate is also considered exotic because it contains tiny relativistic particles called Weyl fermions. Again, surprisingly, though predicted by Hermann Weyl in 1929, these exotic particles, discovered in 2015 in crystals, move like light and can spin in different ways – left-handed or right-handed. Their electronic properties are very strong and resist certain types of disturbances or impurities, making them very stable when operated as a part of electronic devices. As a result, pyrochlore iridate can conduct electricity very well, respond in unusual ways to magnetic fields and show special effects when exposed to electromagnetic fields.

Chakhalian said the combined properties of the new material created makes it a promising candidate for use in advanced technologies, including quantum computing and especially for the next-generation quantum sensors.
“This study is a big step forward in material synthesis and could significantly impact the way we create quantum sensors and advances spintronic devices,” he said.

Quantum computing employs the principles of quantum mechanics to process information. Quantum computers use quantum bits or qubits that exist in multiple states simultaneously due to a quantum physical principle called superposition. This allows for complex computations to be performed much more efficiently than by classical computers.

The specific electronic and magnetic properties of the material developed by the researchers can help in creating very unusual and yet stable quantum states, which are essential for quantum computing.

When quantum technology becomes practical, it will significantly impact ordinary life by revolutionizing drug discovery and medical research, markedly improving operations, predictability and cost savings in finance, logistics and manufacturing. It also is expected to revolutionize machine learning algorithms, making artificial intelligence systems more powerful, the scientists said.

For more information: Nano Letters

Image: By building a unique, advanced machine, Rutgers scientists have created a structure with quantum qualities. The green window (right) is the main growth chamber where synthesis of the quantum “sandwiches” occurs. Within the amber window (left) are advanced characterization tools that uncover chemical and electronic properties of the grown quantum thin films without exposing them to air.