Nanoscience and Advanced Materials

128th Distinguished Research Lectureship: Michael McGehee

Daniel Morton — Tue, 13 Oct 2026 15:42:19 +0000

128th Distinguished Research Lectureship: Michael McGehee Daniel Morton Tue, 10/13/2026 - 09:42

Daniel Morton

Michael McGehee, Patten Chair Professor in Chemical and Biological Engineering, and RASEI Fellow, has been selected as a ��ñ�� 2026-2027 Distinguished Research Lecturer.

Harnessing Sunlight and Mentoring Startup Founders to Address Climate Change

Michael McGehee

Wednesday, November 18, 2026

4:00 - 5:00 PM

Chancellors Hall and Auditorium, CASE

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The Distinguished Research Lectureship is among the highest honors bestowed by the faculty of ��ñ�� upon a faculty member. The selection is made based on the scholarship, research, and creative achievement of the nominee, in this case recognizing McGehee’s mission to use materials science to mitigate and combat the impacts of climate change.

Research in the McGehee group has deep roots in using nanoscience to solve big problems. Earning his undergraduate degree in Physics from Princeton University in 1994, Mike moved across the country to the University of California at Santa Barbara to pursue his graduate studies. Working in the lab of Alan Heeger (Nobel Laureate in Chemistry in 2000 with Alan MacDiarmid for “their discovery and development of conductive polymers”), Mike designed and built a polymer-based laser, triggering a fascination with how materials emit and absorb light. Completing his Ph.D. studies in 1999, Mike moved north, joining the faculty of Stanford University in 2000 where he began his independent research career. The McGehee group moved to ��ñ�� in 2018.

Research in the McGehee group set out with one ‘simple’ mission statement, to use materials science to prevent climate change. This has provided a rich space for scientific investigation, delivering an excellent forum for group members to explore new directions and ideas and for the team to build successful collaborations across academia and industry, as well as address some of the most pressing challenges. Two key areas have emerged in recent years that will form the basis of this year’s lecture, one focused on how we harvest energy from light, the other on how we regulate light. While the lecture is built around these scientific challenges, McGehee emphasizes that the main thread of the talk, that is foundational to the science, is the culture and approach to research that his team has established.

Early work in the McGehee group set out with the aim of creating a solar technology that would provide at least 20 % of the world’s energy. The goal was to use organic molecules to harvest the energy, replacing the conventional silicon-based cells. Solar cells based on these organic molecules offer several benefits, being flexible instead of rigid makes manufacturing more affordable (taking advantage of printing approaches), producing a more robust device, and offering new form factors. Though the promise of organic solar cells has yet to be realized, McGehee’s team identified a promising approach along the way, inventing perovskite tandem solar cell technology. This device architecture stacks a layer of new material, so-called perovskites, on top of the silicon layers present in conventional solar cells. One might think that by adding a layer on top of solar cell you would decrease the efficiency of how it absorbs light, (like putting on sunglasses over the absorber), but in this case the opposite is true. Sunlight is made up of a range of wavelengths, think about the rainbow going from the low energy reds through to the high energy violets. Silicon absorbs best at the low energy end, essentially absorbing the red and orange wavelengths. The perovskite materials absorb at the higher wavelengths, harvesting the energy of the blue and violet wavelengths. By stacking these on top of each other more energy from the sun is collected overall and less is lost to waste heat. The McGehee group has developed tandem perovskite-silicon solar cells that are 30 % more efficient than current conventional silicon solar cells. This technology is now being advanced by more than a dozen companies, including spinouts from the McGehee group Swift Solar and Tandem PV working to manufacture the next generation of solar panels in the United States. McGehee now leads the DOE-funded TEAMUP consortium of academic, national lab and industrial partners focused on solving the challenges associated with scaling and commercializing this technology.

The environmental impacts of energy can be mitigated not just by changing how we generate electricity, but also how we use it. Improving the efficiency of technologies reduces the consumption, cost, and impact of their energy use. Buildings account for around 30 % of global energy demand. In advanced economies this is primarily used for heating and cooling the air. The McGehee group focused on how they could control sunlight, in this case regulating how it enters buildings. Occupants want the insulation of a wall but with the transparency of glass – no one wants to live in a dark box! The group explored the use of electrochromic materials, materials that change their light transmission characteristics upon the application of a voltage. The group invented windows with adjustable tinting that can reduce heating, cooling, and lighting costs in buildings by an estimated 20 %. Tynt Technologies, founded in 2020, is commercializing this smart window technology, demonstrating an industry-leading light transmission range, from 0.01 % - 90 % transmission.

Talk to McGehee about his research and you find someone who is passionate and excited to solve big problems and apply new scientific ideas in making an impact on society. Rapidly the conversation turns to talk about his current and former team members and all of the great work they are doing. There is an enormous sense of pride in their achievements. Students who have worked in the McGehee group have now founded 22 companies, making an impact across a wide range of technologies. The scope of them is broad, manufacturing everything from solar cells and thermal storage materials, through circuits that connect batteries in electric vehicles and electrodes in batteries, to energy efficient windows, flexible OLED displays and microLED displays for augmented reality eyewear. This breadth of exploration is testament to a training that encourages the development of a problem-solving approach that can be leveraged to work on many different problems. As part of this lecture McGehee will explain what he has learned about what the startup founders he has mentored do that makes them successful, especially when they turn their attention to problems that are unrelated to the ones they addressed as students. These lessons are the basis of what McGehee teaches in the new Boulder Climate Ventures course at ��ñ��.

Mike McGehee and Kevin Coakley at CelLink

Outside of work Mike makes the most of what the Front Range has to offer. With a love of the outdoors he can most often be found hiking, biking, or teaching his kids to rock climb.

The ��ñ�� Distinguished Research Lectureship has recognized some incredible talent from across the university. Mike McGehee will deliver the 128^th Distinguished Research Lecture at 4 PM November 18, 2026, we suggest you make plans to attend to find out more about this pioneer materials research for environmental challenges, and how to foster a collaborative and entrepreneurial culture.

OCTOBER 2026

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��ñ��’s “Frozen Air” window material wins gold in R&D 100 Green Tech Awards

Daniel Morton — Fri, 07 Aug 2026 19:21:31 +0000

��ñ��’s “Frozen Air” window material wins gold in R&D 100 Green Tech Awards Daniel Morton Fri, 08/07/2026 - 13:21

Daniel Morton

RASEI Fellow Ivan Smalyukh’s transparent heat-blocking material, MOCHI, just received top honors in the R&D World’s 2026 Special Recognition: Green Tech Category.

Buildings consume roughly 40% of the energy generated worldwide, much of it being lost through windows. Insulating walls is relatively easy, but insulating glass, while keeping it clear, is not. “Finding insulators that are transparent is really challenging,” explains Smalyukh.

MOCHI, the Mesoporous Optically Clear Heat Insulator, is a silicone gel built around a dense network of air pockets that are each many times thinner than a human hair. Because the pores are so small, gas molecules trapped inside them can’t collide and transfer hear in the way they normally do, they just bounce off the walls of the pockets. This means that the material blocks heat so effectively that a 5 mm (1/5 of an inch) sheet can let you hold a flame in your palm. The material transmits 99.5% of visible light, making it clearer than most glass. MOCHI reflects just 0.2% of incoming light, avoiding cloudiness associated with traditional aerogels. The material comes in slabs or thin sheets that could apply directly to existing windows.

Now in its 64^th year, the global science and innovation competition included an international panel of judges, bringing together more than 50 industry professionals. The judges ranked MOCHI gold among three Green Tech honorees, ahead of a carbon sequestering concrete block and solar reflecting cooling paint. All three winners also placed among the 2026 R&D 100 finalists.

This is the second major honor for the Smalyukh group’s push to develop practical transparent insulation technologies. In 2024 the team’s cellulose-based aerogel, SiCellA, earned a Guiness World Record for the most transparent material ever made.

MOCHI is still made by hand in the lab, but the team says that the ingredients are inexpensive and the process can be streamlined. Before it can be deployed in real windows, skylights, and even vehicle windshields, manufacturing needs to be scaled up, the next milestone on the development from lab bench to commercialization.

AUGUST 2026

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RASEI Welcomes Cheng Wang: Building Smarter, Leaner Hardware for the AI Era

Daniel Morton — Thu, 23 Jul 2026 18:23:13 +0000

RASEI Welcomes Cheng Wang: Building Smarter, Leaner Hardware for the AI Era Daniel Morton Thu, 07/23/2026 - 12:23

Daniel Morton

New Assistant Professor brings expertise in energy-efficient computing to RASEI’s research community

RASEI is pleased to welcome Cheng Wang as an incoming Assistant Professor, who will also be in the Department of Electrical, Computer, and Energy Engineering (ECEE) at ��ñ��. Wang is internationally recognized for developing innovative computing hardware that dramatically reduces the energy required for artificial intelligence and other data-intensive applications.

As the increase in AI use drives rapid growth in data centers, much of the conversation has focused on providing electricity and cooling. Wang’s research tackles the challenge from a different direction: making the computers themselves fundamentally more energy efficient through new hardware architectures inspired by the human brain.

Wang joins ��ñ�� from Iowa State University, where he has spent the last four years building a multidisciplinary research group. Wang brings with him experience that spans both academia and industry, including time as a lead research scientist at Purdue University’s Center for Brain-Inspired Computing and as an R&D Engineer at Seagate Technology. Cheng earned a B.S. in Physics from Peking University and his Ph.D. from the University of Texas at Austin. The work produced by the Wang Group has already received wide recognition, with the funding of an NSF CAREER Award and multiple best paper honors. We’re excited to welcome him, and his research group, into the RASEI community.

Most current computer chips spend as much energy moving data between where the data is stored (the memory) and where the computation is done (the processor) as they do actually processing it. This is a decade-old inefficiency often called the “memory bottleneck”. It is like designing a kitchen where the pantry is on the opposite side of the building to where the stove is. Every time the cook needs an ingredient they must run across the building to grab it. Wang’s research asks what would happen if the chip could compute in the same location as where the data is already stored? The Wang Group designs “in-memory computing”, systems that do exactly that, along with the specialized designs of circuits and architectures that efficiently connect individual computing cores into a scalable system. By removing the need to shuttle data back and forth, significant energy reductions are possible in every single computation.

Another energy-saving approach the Wang Group are exploring begins by asking a more fundamental question: Instead of ‘forcing’ brain-like computing onto current designs of silicon chips, which were never designed for that kind of processing, how much performance and efficiency gains would we get by using hardware that was designed to behave more like a biological brain? The Wang group builds circuits made from nano-electronic and nano-magnetic materials, to behaviorally emulate how biological neurons fire and how synapses strengthen or weaken. Instead of having the typical digital “on/off” states, a more analog “gradient” of states is possible. These approaches have the promise to not simply drive down the energy required for computing, but also open up new approaches and opportunities for alternative modes of computation.

Wang’s research sits at the intersection of computing and energy efficiency, at a time when this is front and center for many communities. As artificial intelligence is being woven into much of today’s business and communication, the electricity demands of the data centers running it are of increasing concern; a core element of RASEI’s mission. Wang’s work on ultra-efficient, brain-inspired hardware offers a path toward a more efficient AI system. We are looking forward to the connections, ideas, and directions the Wang Group will bring to the RASEI research community.

Cheng explains that there were multiple draws that brought his team to the RASEI community. “I am excited to explore collaborations across the full stack of designing new devices and architectures”, said Wang. The expertise in materials science and device design present in the RASEI community, across ��ñ�� and NLR, are natural partners to the research being done in the Wang group. “I can see many ways in which our research can develop to engage different aspects of the RASEI community” commented Wang. Of particular interest is the opportunity to engage with a new testbed being built at NLR for high-performance computing, specifically focused on optimizing energy efficiency. Cheng and his family are excited to be moving to the mountains, “When possible, I have biked everywhere since the sixth grade, so we are looking forward to exploring the bike paths across the area”.

Seth Marder, Director of RASEI, welcomes Cheng Wang to the community. He says that “Cheng’s research adds a new dimension to RASEI. As AI and data centers grow, much effort focuses on efficient delivery of power and cooling. However, reducing computing energy consumption is equally important. Cheng pioneers innovative approaches to improve computing hardware efficiency. I’m excited to see his impact and believe he’ll help RASEI advance energy-efficient AI and data center technologies”.

Bri-Mathias Hodge, Interim Department Chair of ECEE, highlighted the departments enthusiasm for the addition of Cheng Wang, adding: “We are excited to partner with RASEI to bring another great faculty member to campus. Cheng’s research is an exciting addition to the department, helping us bridge multiple areas of research strength.”

Please join us in welcoming Cheng Wang to RASEI. Take the opportunity to introduce yourself to him and his team.

JULY 2026

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The Hidden Chemistry Inside Tomorrow’s Solar Cells

Daniel Morton — Thu, 23 Jul 2026 16:06:02 +0000

The Hidden Chemistry Inside Tomorrow’s Solar Cells Daniel Morton Thu, 07/23/2026 - 10:06

Daniel Morton

Researchers uncover why perovskite solar cells degrade under reverse bias, opening new pathways to longer-lasting solar technologies.

Researchers just figured out why perovskite solar cells break down surprisingly easily under partial shading, and how to stop it. Perovskite solar cells are among the most promising candidates for the next generation of solar technology. They can convert sunlight into electricity with remarkable efficiency while offering the potential for lower manufacturing costs than today’s silicon-based panels. Before they can be scaled and deployed, there are some critical challenges to be solved, including ensuring the cells remain stable for decades under real-world conditions. A central question has been what happens when a perovskite solar panel is pushed into an unusual electrical state known as reverse bias.

Like all solar panels, perovskite solar cells occasionally experience reverse bias, an unusual electrical condition that can occur when part of the solar panel is shaded while the rest is in full sunlight. It has long been known that reverse bias quickly damages perovskite devices, but the pieces were not all fitting together. Current flowing through the cell under reverse bias is at the heart of the problem, and there are two ways this can happen. The first is apparent if the materials have big defects, electrons bolt through those defects like lightning and fry the cell, an acute failure mechanism. The second mechanism happens even in cells where those large defects are avoided or covered up, current can flow by a process known as quantum tunneling; much like taking a short-cut through interfaces in the cell. This current flows everywhere and while it is less abrupt than electrons flowing through defects, it will cause degradation in the cell over time. This gradual problem is much harder to understand because seeing these subtler processes in the cell is not easy. Existing theories explained parts of the problem, but they couldn’t fully account for how quickly some cells degraded or why certain device architectures proved far more resilient than others. Something important was happening inside the device that researchers couldn’t yet see.

Late last year, in October of 2025, a report led by RASEI Fellow Michael McGehee, a Professor at the ��ñ��, in collaboration with researchers at the National Laboratory of the Rockies (NLR; then named NREL), that explored the underlying mechanisms of the abrupt failure mechanisms of perovskite films under reverse-bias was published in Joule. The team identified that the defects were the sites of failure and demonstrated how to create films without defects that were much more robust to exposure to reverse bias.

To explore and better understand the gradual mechanism for degradation Michael McGehee assembled a new team of collaborators with the required expertise, including the groups of Edward Sargent from Northwestern University, Neal Armstrong at the University of Arizona, David Ginger at the University of Washington, and Joey Luther another RASEI Fellow at NLR. Together they combined advanced time-resolved electrical measurements, device modeling and materials characterization to watch how perovskite solar cells responded under reverse bias conditions, just published in Joule. Rather than just observing the damage, they set out to answer the key question of what hidden process was driving it?

The layers inside a solar cell create an energy landscape that electrons must navigate to get through the cell. By design, the interfaces act as energy “mountains” separating two valleys where electrons can be. Under reverse bias, ideally electrons cannot get over (or through) the mountain; the mountain is wide enough to keep electrons where they belong, and no current flows. Using these advanced measurement techniques, the team, led by Kell Fremouw (a Graduate Student in the McGehee group) and Ryan DeCrescent (a Research Associate with the McGehee group) was able to investigate the current-flow and degradation mechanism in remarkable detail. They were able to uncover a hidden process that had largely escaped attention: Under reverse bias, electrochemical reactions inside the solar cell weren’t just moving charged particles around as previously thought, they were actually creating new mobile ions. As these newly created ions redistribute and accumulate near interfaces, they gradually reshape the energy mountain, making it thinner until quantum tunneling becomes easy, and making it much easier for damaging current to pass through. Essentially the shifting chemistry was changing the device physics, providing important insights into why some device architectures show electrical breakdown and degrade much faster than existing models could explain.

These observations underlined an important perspective about these devices. Rather than simply behaving as electronic devices that move electrical charge, the cells also function as tiny chemical systems, with electrochemical reactions reshaping their internal structure under certain conditions. The initial device physics governs the ion creation, and the ion creation changes the device physics; this is an important feedback loop that can accelerate degradation. Identifying the hidden chemistry gives the researchers a much clearer picture of why the degradation occurs, and possible ways to prevent it.

Based on these findings, the team was able to identify where to intervene. The answer isn’t to try and repair the damage after it has begun, but to stop the chemical reactions from starting in the first place. By improving on the ultra-thin transport layers inside the device, the so-called hole transport layer (or HTL), the researchers showed that they could block the reactions responsible for creating new mobile ions. This solution is one that doesn’t require new equipment or exotic new materials, the team used standard materials and procedures but ensured that the layer placed in the device was very smooth, improving the coverage of the layer. With the electrical landscape preserved, the pathway to damaging currents remains closed, helping the cells maintain their performance for longer.

This new work, in combination with the study published last year, provides a holistic view of the two pathways that lead to perovskite decomposition under reverse bias. Importantly, both studies go beyond just observing the problem, they offer proven approaches to solve the abrupt and gradual degradation pathways. Preventing reverse bias degradation is a crucial component for the commercialization of perovskite solar cells.

For devices that may one day be expected to operate for decades on rooftops and in solar farms around the world, understanding the failure points is as important as improving efficiency. Efficiency will often get the headlines, but durability and resilience will decide whether perovskites make it onto a rooftop. This work doesn’t just observe and explain a failure mode, it provides a solution for one of the major challenges to scaling this new technology.

JULY 2027

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A New Dial for Controlling Light-Driven Chemistry

Daniel Morton — Tue, 21 Jul 2026 17:45:04 +0000

A New Dial for Controlling Light-Driven Chemistry Daniel Morton Tue, 07/21/2026 - 11:45

Daniel Morton

RASEI Fellow Niels Damrauer (��ñ��) and a multidisciplinary team initiated by Professor Zach Wickens at the University of Wisconsin Madison just found a new way to control which molecules react in light-driven chemistry. The key to unlocking this new pathway? Focus on what happens after the reaction starts, not before.

SET: A powerful reaction for building organic molecules, such as medicines and materials

This type of reaction, called single electron transfer (SET), is one of the most useful tools in modern chemistry. It can be initiated by swapping in light or electricity instead of heat, making it more energy efficient and less prone to generating waste products. But there have always been some limitations with SET. Some molecules just don’t want to accept an electron, particularly when there are other types of molecules nearby that do the reaction faster, meaning that they’ve been locked out of this chemistry, until now. The new study, published in Nature with collaborators Zachary Wickens from the University of Wisconsin-Madison and Robert Paton at Colorado State University, opens the door to reactions that were previously impossible.

How Single Electron Transfer Works

One molecule, commonly after absorbing light, transfers an electron to another, triggering a reaction. Researchers have previously controlled the outcome of the reaction by picking molecules based on how ‘eager’ they are to grab, or accept, that electron. The molecule most ready to accept the electron wins. This approach has produced a wide range of really impressive chemistry, but it leaves out any molecule that isn’t ‘interested’ in the electron to begin with.

Identifying an opportunity

Every SET reaction actually has two steps, not one. First, an electron is transferred from a donor molecule to an acceptor molecule. Then, it has an option, it can either go forward to trigger a reaction, or it can go backward, undoing the first step. It is reversible. Chemists have always focused on controlling the first electron transfer. This team asked what would happen if they found a way to control the second electron transfer instead.

An extreme electron donor

To test this idea the researchers built what they call a “super-potent photoreductant”. It’s a light-activated catalyst that hands out electrons to almost every nearby molecule, good at accepting or not. In this particular research, the reductant is a solvated electron released from a photoexcited catalyst. Damrauer and his student Arindam Sau used time resolved spectroscopies to disentangle mechanism and identify conditions, such as the wavelength for photoexcitation, where catalysts could function. Damrauer notes, “By analyzing time-resolved signals in our experiment, my student Arindam was able to find colors for photoexcitation where the electron, the reductant, would be released deeper into the solvent, thereby affording it time to do its work in reducing the substrate molecules in solution.” But shouldn’t this reducing potency wipe out selectivity entirely? If every molecule gets an electron, which one ‘wins’?

RASEI Fellow Niels Damrauer at the graduation of one of the lead researchers Arindam Sau (Boulder, CO, 2026).

Reversibility is the key

The opportunity comes down to the second electron transfer. If a molecule accepts an electron, but doesn’t react quickly, the electron slips back to the catalyst and molecule floats away unchanged. If the molecule does react quickly, in a non-reversible way, the electron doesn’t go back to the catalyst and the reaction moves forward. Selectivity now depends on how reversible the electron transfer is, not how easy the initial electron transfer was.

Building a model reaction to test the hypothesis

The team tested this using a mixture of two molecules side by side: One that accepts electrons readily, but also gives them back easily, and one that ‘reluctantly’ accepts electrons, but then holds on tight once it does through a structural change. Under the old rules, the ‘eager’ electron acceptor would win. Under the new rules the ‘reluctant’ one wins, moving forward along the reaction pathway, leading to the formation of a new product that would not have been otherwise possible. Through a series of experimental explorative and optimization reactions the team were able to confirm that this selectivity preference held across a broad range of related molecules, not just the one test case.

No molecules left behind

With this works chemists now have a new dial to turn. Molecules that were previously incompatible with this efficient, light-driven chemistry are now available. This opens new pathways for building medicines and advanced materials, using less energy and creating less waste along the way.

JULY 2026

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CHOISE Scientific Collaboration Awarded the 2026 Royal Society of Chemistry Faraday Horizon Prize

Daniel Morton — Wed, 24 Jun 2026 00:41:23 +0000

CHOISE Scientific Collaboration Awarded the 2026 Royal Society of Chemistry Faraday Horizon Prize Daniel Morton Tue, 06/23/2026 - 18:41

Daniel Morton

The Center for Hybrid Organic-Inorganic Semiconductors for Energy (CHOISE) has been awarded the 2026 Royal Society of Chemistry (RSC) Faraday Horizon Prize, in recognition of its creation of a new class of chiral semiconductors that unify the control of spin, charge, and light within a single electronically active material platform.

CHOISE is a Department of Energy-funded Energy Frontier Research Center (EFRC) bringing together 17 research groups from nine institutions: the National Laboratory of the Rockies (NLR), Duke University, the ��ñ��, the University of North Carolina at Chapel Hill, North Carolina State University, San Diego State University, the University of Toledo, the University of Utah, and the University of California Santa Cruz. The Center includes seven RASEI Fellows, and is led by Fellow Matt Beard of NLR.

RASEI Fellows Kirstin Alberi (NLR), Steve Barlow (��ñ��), Joseph Berry (NLR), Jeff Blackburn (NLR), Joseph Luther (NLR), and Seth Marder (��ñ��) are all part of the collaboration.

The RSC Faraday Horizon Prize is awarded annually in recognition of significant recent discoveries and advances in physical chemistry. In selecting CHOISE, the prize committee highlighted both the scientific excellence and the collaborative character of the work, recognizing how the team has come together across disciplines and institutions to develop innovative ideas.

At the heart of CHOISE's prize-winning research is chirality, the property by which molecules exist in distinct left- and right-handed forms. By embedding chirality directly into a semiconductor, the team has demonstrated that molecular handedness can govern the behavior of charge carriers and their spin. This establishes a fundamentally new paradigm for spin-dependent optoelectronics: technologies that use both light and electrical signals to process and transmit information.

Optoelectronic devices already underpin much of modern life, from the fiber-optic networks that carry global internet traffic, to the sensors in medical imaging, and the LEDs and lasers in everyday electronics. However, the next generation of technologies, including applications such as quantum computing, ultra-secure communications, and energy-efficient data processing, will demand far greater control over the quantum properties of electrons, particularly their spin. Conventional semiconductors offer limited means to achieve this. This is where this work comes in. CHOISE's chiral semiconductor platform opens a new route to that control, using the inherent geometry of molecules rather than complex external hardware to influence the properties of the signal. This could ultimately lead to devices that are not only more powerful, but significantly more energy-efficient.

JUNE 2026

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The solar cell that moonlights as an LED, and does both better

Daniel Morton — Mon, 27 Apr 2026 22:30:02 +0000

The solar cell that moonlights as an LED, and does both better Daniel Morton Mon, 04/27/2026 - 16:30

Daniel Morton

Imagine a display that harvests ambient light when it is not actively in use, offsetting some of its own energy consumption. The materials physics shows that this is possible, the same semiconductor material can, in principle, emit and absorb light efficiently. What has been missing is a device architecture that allows it to do both without reductions in efficiency of either application. A new study reports a perovskite diode that converts sunlight to electricity at 26.7% efficiency (a world record at the time of publication submission) and emits light at 31% efficiency, figures that would be high for a device designed to do only one of those things.

Find out more

Read the Article here

EurekAlert!

The Brighter Side

Metal-halide perovskites are a class of materials named for their distinctive crystal structure, that have emerged over the past decade as some of the most promising candidates for next-generation solar cells and light-emitting diodes (LEDs). They are relatively inexpensive to produce, can be tuned to absorb or emit different wavelengths of light, and have shown efficiency levels that rival far more costly semiconductor materials. Yet despite sharing the same underlying material, perovskite solar cells and perovskite LEDs have largely been developed as separate technologies, because the physical requirements of each push device design in opposite directions. A collaborative study published in Joule by a team led by Michael McGehee at the ��ñ��, and Jixian Xu at the University of Science and Technology of China, now demonstrates that this conflict can be resolved, and that resolving it improves both devices at once.

The challenge of doing two things at once

The tension between perovskite LEDs and solar cells comes down to a question of thickness. An effective LED needs an extremely thin, discontinuous layer of perovskite, typically around 50 nanometers (roughly one thousandth the width of a human hair), because thin, slightly uneven films naturally scatter light outward, helping photons escape the device. A solar cell, by contrast, needs a layer roughly sixteen times thicker to absorb enough incoming sunlight and convert it into electricity efficiently. For years, this meant that researchers optimizing a perovskite LED were building something poorly suited to harvesting solar energy, and vice versa. Thanks to these different needs the two applications have followed separate architectural paths, and devices that attempted to do both tended to do neither particularly well.

There is a further complication. Even in a well-made perovskite LED device, much of the light generated inside never escapes. When a photon (a particle of light) is produced inside the material, it travels outward and hits the surface. If it arrives at too steep an angle, it is reflected back inside rather than escaping, a phenomenon governed by the physics of how light moves between materials with different optical properties. Once trapped, that photon bounces around until it is absorbed by a microscopic defect in the material and converted to heat, essentially wasted energy. Reducing these losses requires both giving trapped photons a better route out and patching the defects that absorb them along the way. These have typically been treated as separate engineering problems.

A useful way to think about what the team describe in this research is to consider what a texture does to a pane of glass. Smooth, flat glass transmits light reasonably well in one direction, but offers little control over what happens to light approaching from awkward angles. Some passes through, some reflects, and the behavior is largely determined by the geometry. A textured or patterned surface changes this: by introducing deliberate variations in the surface structure, light arriving from many different angles can be redirected more usefully, whether that means bending it inward toward an internal target (for a solar cell) or redirecting it outward toward an observer (for an LED). The same surface feature serves both directions of travel. The team's approach works on a closely related principle, applied to structures far smaller than any surface texture visible to the naked eye, and with the added benefit that the material forming those structures also repairs the defects that were previously wasting energy as heat.

Building porous textured sponges

Building on earlier collaborative work published in Science in 2023, by McGehee and Xu, which demonstrated that porous alumina nanoplates (a form of aluminum oxide) could reduce energy losses at perovskite interfaces, the team set out to extend that principle into a more sophisticated architecture. The key advance was developing a method to assemble alumina nanoparticles into micrometer-sized islands (each around five micrometers across and half a micrometer tall) embedded within the perovskite device. The assembly process uses electrostatic attraction: two populations of alumina nanoparticles are given opposite surface charges, and when mixed, they cluster together naturally into porous, sponge-like islands. One population is treated with a negatively charged molecule (Me-4PACz) and the other population treated with a positively charged molecule (ODA). The team refer to these as e-Al₂O₃, where the "e" denotes “electrostatic” assembly.

The porous sponge-like structure is critical. Earlier approaches to introducing low-refractive-index materials (materials that are less optically dense than the surrounding perovskite) into LED devices tended to block the flow of electrical charge, undermining device performance. Because the e-Al₂O₃ islands are porous, the perovskite material can grow through them, maintaining electrical contact with the electrode beneath. The islands therefore redirect light without interrupting the charge transport the device depends on.

The surface treatments applied to the alumina nanoparticles were designed to serve a second, equally important function. The molecules used to give the particles their opposite charges are the same molecules known to passivate perovskite surfaces, essentially chemically neutralizing the defects where energy can be lost as heat. The surface recombination velocity, a measure of how quickly electrical charges are lost at interfaces, dropped from 20.2 cm/s in a flat control device to 1.4 cm/s in the e-Al₂O₃ device. This brings the rate of energy loss at the interface close to levels seen in high-performance silicon solar cells.

With defect losses suppressed to this degree, a useful secondary effect called photon recycling becomes significant. When a photon is generated inside the perovskite and would otherwise be trapped and lost, it now has a reasonable chance of being reabsorbed by the material and re-emitted, effectively getting a second, or third, attempt to find an exit. This would be counterproductive in a defect-rich material, because each reabsorption event would risk the photon being lost to heat. However, with defects minimized, photon recycling amplifies the benefit of the improved light routing, pushing external efficiency higher than the geometry of the device alone would predict.

Operated as a solar cell, the e-Al₂O₃ device achieved an externally certified stabilized power-conversion efficiency of 26.7%. At the time this work was submitted for publication this cell held the world record for the power conversion efficiency for perovskite devices (held between 05/2024 – 02/2025). Operated as an LED with the same 800 nm thick perovskite layer, the device reached an external quantum efficiency of approximately 31%, meaning roughly 31 out of every 100 injected electrons produced a photon that successfully escaped the device. Radiance (a measure of light output intensity) was nearly ten times higher than the flat control device. Across both operating modes, the e-Al₂O₃ devices also showed meaningfully improved long-term stability, retaining 95% of their initial solar cell efficiency after 1,200 hours of continuous operation, compared with 67% for the flat control.

The authors note that this combination of greater than 26% solar cell efficiency and greater than 30% LED efficiency in a single polycrystalline device is, across all photovoltaic materials, only the second time this has been demonstrated, the first being single-crystal gallium arsenide, a material that is substantially more expensive and more difficult to manufacture at scale.

The practical implication of a device that converts sunlight to electricity efficiently and emits light efficiently is not merely academic. Displays that harvest ambient light to extend battery life, or lighting systems that recover energy when not actively in use, become more plausible when the same device architecture serves both functions without meaningful compromise in either. More fundamentally, the work demonstrates that the long-standing separation between emissive and photovoltaic device design is not a physical inevitability but an engineering problem, one that careful co-optimization of optical and electronic properties can address.

April 2026

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The Physics That Hides in Plain Sight

Daniel Morton — Wed, 22 Apr 2026 15:30:34 +0000

The Physics That Hides in Plain Sight Daniel Morton Wed, 04/22/2026 - 09:30

Daniel Morton

Just published; a Perspective article by RASEI theorists raises new questions on what is hidden by quantum symmetry

More Information

Check out the Perspective Here

Some of the most interesting actions happening inside a material are the things that, according to the rulebook, shouldn't be happening at all. In the world of quantum physics, that rulebook is written by symmetry, as encoded by the geometric arrangement of atoms in quantum matter. Essentially, how the atoms are stacked together in a solid. Symmetry sets strict rules about what physical effects are, and are not permitted. For decades, when experiments on certain materials produced results that symmetry said were impossible, the standard assumption was that something had gone wrong: a flawed measurement, or a contaminated sample. A new framework published by the group of Alex Zunger in the journal Matter suggests that in many of those cases, nothing had gone wrong at all. The effects were real. Indeed, they were just hidden—permitted by the local symmetry rules operating in small regions, or neighborhoods, not by the material's overall structure. Understanding where and how these hidden effects occur has practical consequences: the behavior of electrons in magnetic materials underpins technologies from computer hard drives to medical sensors, and knowing the full picture of what electrons can do can save us from discarding potentially critical new materials with hidden technological virtues.

Spin, and why it matters

To understand what this framework is doing, it helps to start with spin itself. Spin is a quantum property of electrons, one that has no obvious everyday analogy, but which causes electrons to behave, in some respects, like tiny magnets with a fixed orientation. In most materials, the spins of individual electrons point in random up or down directions and cancel each other out. But in certain materials, and under certain conditions, spins can be organized spatially and can be controlled. Moreover, even when spins cancel each other out over the global volume of a sample, the local rules operating in smaller regions can have a different spin symmetry, controlling the properties of the sample as a whole.

These unusual spin behaviors control the foundation of a field called quantum spintronics. Spintronics is, broadly, the use of electron spin rather than just electron charge to store, process, and transmit information. The hard drives in most computers already exploit this principle: the read heads that detect stored data work by sensing differences in how electrons with different spin orientations pass through a material. Researchers are working towards spintronic devices that are faster, smaller, and more energy-efficient than what charge-based electronics alone can achieve.

The catch is that developing useful spin behavior out of a material requires the right conditions. This is where symmetry re-enters the picture. The chemical identity and spatial arrangement of atoms in a solid determine its overall properties. Change the atomic arrangement, and you change what spin can do. For this reason, identifying which materials have the right symmetry for a given spin effect has been central to the field. And for a long time, if a material's overall symmetry appeared to rule an effect out, that material was simply set aside.

Walking the streets: a new map of spin physics

The new framework addresses this directly. Rather than treating spin effects as simply present or absent in a given material, it draws a distinction between two types: apparent and hidden effects.

Apparent effects are those that follow directly from a material's overall atomic arrangement. If the global symmetry permits a spin effect, you expect to see it, and you do. Hidden effects are more subtle. They occur in materials where the overall atomic arrangement would, according to the current rulebook, forbid a given behavior, but where smaller, localized regions, or neighborhoods, within the material have their own legitimate symmetry that permits it. The global picture says no; the local picture says yes. The local picture wins. To comprehensively understand the potential spintronic virtues of a material, we need to also understand the mysteries of the local arrangements and symmetries of the spins.

A good way to think about this is to imagine judging a city's architecture and character purely from a satellite image. At that resolution, everything might look uniform and regular. Walk the streets, and observe the neighborhood at eye level, and an entirely different set of structures and interactions becomes visible. The framework outlined in this Perspective is insisting that materials physics needs to walk the streets, and that a great deal can be missed by staying at altitude.

To organize this, the framework described by the Zunger team sorts spin effects in magnetic and non-magnetic materials into distinct categories, determined by two key factors: whether the effect is apparent or hidden and whether the spin effect requires a help from a phenomenon called spin-orbit coupling (SOC)—an interaction emerging from relativistic theory of matter, in which an electron's motion through the electric field of an atomic nucleus influences its spin orientation. Some spin effects depend on this interaction; others do not, and this distinction has meaningful consequences for which materials can host them and how large the effects can be. Check out Box 1 for a deeper dive into these effects.

Box 1:

Apparent spin splitting induced in non-magnetic materials by relativistic SOC: The Rashba and Dresselhaus effect: Across all categories, the framework identifies both an apparent and a hidden version of each effect. The team helps provide understanding around this categorization by providing theoretical physics worked-out examples inspired by real, experimentally studied compounds. For example, in non-magnetic materials, well-known effects called the Rashba and Dresselhaus effects (both involving spin-orbit coupling) producing a separation of electron spin states, have previously overlooked hidden counterparts that can occur in materials whose overall symmetry would appear to rule them out. The framework points to the possibility that there can be materials that violate the nominal conditions for the (apparent) Rashba effect, but a hidden Rashba effect exists. For example, a hidden Rashba effect can show spin polarization even if the global symmetry violates the required broken inversion symmetry, but the structure consists of sectors that are individually non-symmetric. Predicted materials with hidden Rashba spin polarization pointed out by the new framework include tetragonal BaNiS₂ and tetragonal LaOBiS₂, whereas materials with hidden Dresselhaus spin polarization proposed theoretically exhibits local spin texture (the pattern of spin orientations across the material), but no spin splitting include hexagonal NaCaBi, cubic Si, and cubic Ge. This new perspective legitimizes the search for such materials that violate the (apparent) Rashba conditions yet show a (hidden) Rashba effect.

What can be hidden in magnetic materials?

In magnetic materials, hidden spin effects can arise not from the relativistic effect of spin-orbit coupling, but from the magnetic interactions between atoms. This means they can, in principle, be larger, and occur in materials containing lighter, more abundant elements. In both cases, the street-level view of the material is revealing structures and interactions that the satellite image simply could not see. You can find out more about examples of an apparent and a hidden SOC-independent effect in Box 2.

Controlling the electronics of materials

The practical significance of the framework extends beyond classification. The Perspective article explores whether hidden and apparent spin effects can be actively controlled, and, in certain materials, the answer is yes. In some antiferromagnetic compounds, switching between hidden and apparent spin states can be achieved using an electric field. This would be enabled if one could design a material that, in addition to (either apparent or hidden) spin-split AFM symmetry can have the added symmetry of polarity (how electrons are arranged across atoms). This will allow potential applications of the ability to switch spin states using only an electric field.

This is notable for a few reasons. Antiferromagnets carry some practical advantages over the ferromagnets (materials like iron, where all magnetic moments point the same way), that currently dominant magnetic technology. They produce no stray magnetic field, which reduces interference with neighboring components, respond rapidly to switching signals, and are robust against external magnetic disturbances. The ability to toggle spin effects electrically in these materials adds a further tool for device designers to work with.

Box 2:

Apparent, SOC-independent spin splitting in antiferromagnetic materials: Spin configurations consisting of alternation of spin-up layer followed by a spin-down layer are called antiferromagnets. For a long while it was textbook knowledge that electronic states in antiferromagnets would have the same energies for spin-up and spin-down layers (a behavior called “spin degeneracy”) in the absence of SOC. This is because it was assumed that the two atoms with opposite spins will compensate each other, giving rise to spin degeneracy. In 2020, the Zunger group with Emmanuel Rashba discovered the enabling symmetry conditions for the unusual case where electronic states in an antiferromagnets would have different energies for different spin (“spin-split antiferromagnets”) in the absence of SOC. Since this behavior follows the precise symmetry of the system it constitutes an apparent effect. Theorists soon pointed to real materials that would have such peculiar effects, including orthorhombic LaMnO_3, rhombohedral MnTiO₃, tetragonal KRu₄O₈, and tetragonal V₂Te₂Oand many others. This effect was later dubbed in the literature “altermagnetism” implying another form of magnetism.

Hidden, SOC-independent spin polarization in antiferromagnetic materials: In collinear antiferromagnets (collinear, meaning the psins all point along the same axis), this requires that (i) global system symmetry forbids SOC-independent spin splitting, but the (ii) local sectors break that symmetry. Predicted hidden spin polarization materials in magnetic AFM include tetragonal Ca₂MnO₄, La₂NiO₄, and MnS₂, and the following tetragonal compounds CoSe₂O₅, Fe₂TeO₆, K₂CoP₂O₇, LiFePO_4, Sr₂IrO₄, and SrCo₂V₂O₈.

Finding real materials with previously unsuspected hidden effects

The question is how one can use theoretical physics to search for specific materials with target spintronic properties? The history of material research and condensed matter physics has often proceeded via accidental discovery of materials with interesting physical properties—superconductors and light-emitting semiconductor. Yet, for many applications we know well what type of physical properties we want, but we do not know a material that has those target properties. An interesting advance was worked out in the research group of Alex Zunger: namely “Inverse Design”, where you find a material that has a specific, desired target property. The obvious obstacle is that there are innumerably many possible atomic structures that could, in principle, be made even from a few elements and we do not know which structure would have the desired target property. It turns out that modern atomic-resolution quantum mechanics (i.e., electronic structure theory) can now be combined with biologically inspired (evolutionary) “Genetic Algorithms” to scan a truly astronomic number of atomic configurations in genomic-like search of the one(s) that have desired, target materials properties. Once the number of configurations with target property is narrowed down to a few, laboratory synthesis becomes viable. Examples of specific compounds, known to exist but not known to be spintronic relevant were predicted theoretically as a result of this work.

A broad implication of this new framework is that the rulebook has been applied too rigidly. By demonstrating that hidden effects are real and systematic rather than accidental, the framework significantly expands the pool of materials worth investigating for spintronic applications. Materials that were previously set aside because their overall symmetry appeared to rule out useful spin behavior may, on closer, street-level, inspection, host exactly the effects that researchers are looking for, just in a form that requires a more careful look to find.

The Perspective also flags a subtler problem. Some of the theoretical tools routinely used to model materials are themselves guilty of the same “farsightedness” that causes hidden effects to be missed. Certain widely used approximations work at too coarse a resolution to detect local symmetry and therefore fail to predict effects that are genuinely present. Refining the theoretical toolkit is, as the authors suggest, as important as expanding the materials search.

Taken together, this framework offers a more complete account of what electrons can do inside a solid, and one that takes local structure seriously rather than assuming the view from altitude tells the whole story. The physics was there all along. It just required a closer look to find it.

April 2026

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BES: Atoms to Bits: Toward Thermodynamic Intelligence

Daniel Morton — Thu, 02 Apr 2026 19:26:24 +0000

BES: Atoms to Bits: Toward Thermodynamic Intelligence Daniel Morton Thu, 04/02/2026 - 13:26

Event Details

Thursday April 2, 2026

SEEC Building N224 | 3:00 - 4:00 PM

Abstract:

As transistors approach atomic limits, heat dissipation has become the defining constraint of modern computing. My research asks a different question: can heat itself be used to compute? Using correlated quantum materials such as vanadium dioxide (VO2), we explore how electronic phase transitions driven by the flow of heat and charge, generate nonlinear dynamics that resemble neural behavior.

I will discuss our recent experiments revealing spiking, synchronization, memory, and stochasticity in Mott oscillators, as well as collective switching in thermally coupled device networks. These studies uncover how local phase transition fluctuations and mesoscale heat transport give rise to emergent order and functional computation. By linking atomic-scale phase transitions to network-level information processing, this work outlines a physical pathway from atoms to bits, pointing toward a thermodynamic framework for intelligent, energy-aware electronics.

Biography:

Erbin Qiu is a Postdoctoral Scholar in Physics at the University of California, San Diego. He received his PhD in the Department of Electrical and Computer Engineering at UC San Diego. His research focuses on energy-efficient, brain-inspired computing, where he develops new electronic devices that use heat and physical dynamics, rather than conventional digital logic, to process information.

His work addresses a fundamental challenge in modern computing: how to advance artificial intelligence while reducing energy consumption and environmental impact. Dr. Qiu has led independent research spanning device design, nanoscale fabrication, and experimental characterization. He is the first and corresponding author of multiple publications in leading journals, including Advanced Materials, PNAS, and Applied Physics Letters. His research has been recognized with several competitive honors, including the Schultz Prize as the sole recipient in the past six years, the Dr. William S.C. Chang Best Dissertation Award (2024) from UC San Diego, and the Von Neumann Distinguished Collaborative Research Award from the U.S. Department of Energy.

April 2026

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BES: Engineering Next-Generation Membranes for Sustainable Separations

Daniel Morton — Tue, 31 Mar 2026 19:20:26 +0000

BES: Engineering Next-Generation Membranes for Sustainable Separations Daniel Morton Tue, 03/31/2026 - 13:20

Event Details

Tuesday March 31, 2026

SEEC Sievers Room (S228) | 10:00 - 11:00 AM

Abstract:

Water scarcity, constrained energy resources, and the accelerating demand for critical materials are defining challenges of this century. As global production of plastics, electronics, and advanced chemicals continues to grow, access to essential resources including lithium, cobalt, nickel, rare earth elements, and energy feedstocks is becoming increasingly limited. These pressures highlight the urgent need for energy efficient separation technologies that can sustainably produce, recover, and recycle resources across the water-energy-materials nexus. Yet separations already account for a significant fraction of global energy consumption, and conventional thermal and extractive approaches are reaching their practical and economic limits.

This seminar will examine recent advances in the engineering of membranes for extreme and nontraditional separation environments. The discussion will cover fundamental insights into polymeric membrane compaction and the development of ultrahigh-pressure and high-temperature reverse osmosis membranes capable of stable operation under severe salinity, pressure, and thermal loading. The seminar will also highlight the expansion of membrane design into crystalline-framework and hybrid systems, including MOF and COF based composite membranes for selective lithium recovery from brines and battery-waste leachates. Collectively, these developments demonstrate how next generation membranes can enable energy efficient separations, advance the energy transition, and promote resource circularity.

Biography:

Dr. Jishan Wu is a Postdoctoral Fellow at the Rice University WaTER Institute. His research focuses on engineering next-generation membrane materials for energy-efficient separations across the water–energy-materials nexus, with applications in critical-mineral recovery, brine management, and industrial process separations. His work integrates polymer science, nanoporous materials, interfacial chemistry, and transport phenomena to enable membrane operation under extreme pressure, temperature, and salinity. His research has been recognized through multiple competitive national fellowships, including the National Water Research Institute–Southern California Salinity Coalition (NWRI–SCSC) Fellowship, the North American Membrane Society (NAMS) Student Fellowship, and the American Membrane Technology Association / U.S. Bureau of Reclamation (AMTA/USBR) Fellowship. He is also a recipient of the Rising Star in Desalination Award and the Elsevier Young Researcher Best Oral Presentation Award. In addition to his research, he serves as an Early Career Editorial Board Member of Desalination and an Editorial Board Member of npj Clean Water.

March 2026

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Nanoscience and Advanced Materials

128th Distinguished Research Lectureship: Michael McGehee

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��ñ����’s “Frozen Air” window material wins gold in R&D 100 Green Tech Awards

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RASEI Welcomes Cheng Wang: Building Smarter, Leaner Hardware for the AI Era

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The Hidden Chemistry Inside Tomorrow’s Solar Cells

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A New Dial for Controlling Light-Driven Chemistry

SET: A powerful reaction for building organic molecules, such as medicines and materials

How Single Electron Transfer Works

Identifying an opportunity

An extreme electron donor

Reversibility is the key

Building a model reaction to test the hypothesis

No molecules left behind

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CHOISE Scientific Collaboration Awarded the 2026 Royal Society of Chemistry Faraday Horizon Prize

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The solar cell that moonlights as an LED, and does both better

The challenge of doing two things at once

Building porous textured sponges

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The Physics That Hides in Plain Sight

Spin, and why it matters

Walking the streets: a new map of spin physics

What can be hidden in magnetic materials?

Controlling the electronics of materials

Finding real materials with previously unsuspected hidden effects

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BES: Atoms to Bits: Toward Thermodynamic Intelligence

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BES: Engineering Next-Generation Membranes for Sustainable Separations

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��ñ��’s “Frozen Air” window material wins gold in R&D 100 Green Tech Awards