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Atomic Musical Chairs: How Tiny Nanocrystals Are Informing the Future of Energy-Efficient Electronics

Daniel Morton — Tue, 17 Mar 2026 19:43:33 +0000

Atomic Musical Chairs: How Tiny Nanocrystals Are Informing the Future of Energy-Efficient Electronics Daniel Morton Tue, 03/17/2026 - 13:43

Daniel Morton

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While most people, when asked about energy innovation, think about some of the "large" technologies, such as wind turbines, long transmission lines, or massive power plants, some of the most important advances in how we use energy are happening at a scale so small that millions of the "machines" involved could fit on the head of a pin.

New research from a team led by RASEI Fellow Gordana Dukovic, working in collaboration with RASEI Fellow Sadegh Yazdi and Prof. Dmitri Talapin from the University of Chicago, reveals new insights on a high-speed game of "atomic musical chairs." This collaboration involved two large teams working together. Researchers from two United States National Science Foundation Science and Technology Centers (STCs) including IMOD and STROBE, employed cutting-edge microscopy techniques to directly visualize, for the first time at this scale, how atoms swap places inside tiny semiconductor nanocrystals, which is a crucial step toward understanding the composition, and ultimately the properties, of these materials.

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NSF STCc

STROBE STC

IMOD STC

Science and Technology Centers are hubs for collaboration, bringing together multidisciplinary researchers from across the United States to solve large, challenging and complex problems. This article describes a space where two of these large networks worked together. STROBE, or Science and Technology Center on Real-Time Functional Imaging pushes the boundaries of microscopy to observe and understand materials at the atomic and nano-scales. IMOD, or The Center for Integration of Modern Optoelectronic Materials on Demand, focuses on making atomically precise semiconductors and integrating them into applications in VR displays, and devices for quantum communication and computing. This team leverages the expertise from both Centers to create new semiconductors and using cutting-edge microscopes to observe and understand them.

Almost all of our electronic devices are built from semiconductors. Whether it is the screen on your smartphone, the components in your car, or the microchips in your computer, these electronics rely on semiconductors. Traditionally, these materials are "grown" through rigid and often expensive processes. Tuning the properties of a semiconductor using this approach is not straightforward. If you want a specific color of light for a display, or a specific energy absorption profile for a solar panel, you often have to start from scratch with an entirely different material.

This is where semiconductor nanocrystals offer remarkable opportunities. The specific size, shape, and composition of these tiny nanocrystals determine the physical and electronic properties of the overall material. A particularly powerful process with such nanocrystals is called cation exchange. Instead of building a new crystal from scratch, you can take an existing one and swap out its internal atomic components to change its properties.

“This is a project that we have been working on for a long time” explains Ben Hammel, a graduate student in the Dukovic Group, and lead author on this research. “We have been looking at these materials from the Talapin Group for a long time”.

This work, just published in ACS Nano, focuses on what are called III–V nanocrystals, which are tiny, four-sided pyramids, or tetrahedrons, named for the groups of the periodic table their constituent elements come from (Group III includes elements like Indium, Gallium, and Aluminum; Group V includes Phosphorus, Arsenic, and Antimony). In this research, the nanocrystals are made of a mixture of Indium, Phosphorus, and Arsenic. To exert more control over the properties of these nanocrystals, the researchers introduced Gallium. Adding Gallium is like tuning a guitar string: it changes the energy of the crystal, influencing how it interacts with light.

“A lot of people have developed ways to make III-V bulk semiconductors, but the real challenge is making them into nanocrystals, where you have more control over their properties, and the Talapin Group have developed a really neat molten salt process to do this” explains Hammel. The molten salt work was published in Science in 2024.

Imagine the inside of one of these tiny crystals as a perfectly ordered lattice of "seats." There are two types of players: Anions (the Phosphorus and Arsenic atoms) and Cations (the Indium atoms). A key observation from the team was that the "house" never moves. The Anions are like the floor and the chairs, they stay perfectly still, maintaining the overall crystal framework. The Cations, on the other hand, are the players sitting in those chairs.

In this work, the nanocrystals were placed into a "hot bath" of molten Gallium salts, essentially starting the music on the game of atomic musical chairs. Previous work had shown that the atoms exchange, but there was not a lot of evidence for how this process worked. “Understanding how this works is very important, and finding out more about the local elemental composition, and how the Gallium atoms move can inform how we design these systems in the future” explains Hammel.

These nanocrystals are only 5 to 10 nanometers wide. A typical human hair is between 80,000 and 100,000 nanometers wide. These crystals are called "nano" for a reason! To observe this game of atomic musical chairs in action, the team used Scanning Transmission Electron Microscopy (STEM), an instrument that uses a focused beam of electrons to probe and image matter at the atomic scale. “Early on there were some signs that there was heterogeneity within the particles, but it was unclear, a big technical challenge we had to overcome was how we can actually measure the Gallium moving through the nanocrystal” said Hammel.

A key challenge they had to figure out was the sensitivity of the nanocrystals to the very tool being used to study them. The electron beam of the STEM, if used at high intensity, can damage the nanocrystals before a useful image can even be collected. To solve this, the team developed an innovative "statistical" imaging approach. Rather than blasting a single crystal with a high dose of electrons to get a sharp image, the researchers instead took many low-dose, and individually blurry, snapshots of hundreds of different crystals at different stages of the molten salt reaction. “We essentially stacked the data on top of each other” describes Hammel, “If I can add together 10 nanocrystals, I can get 10 times the signal”. Adding these kinds of signals together hadn’t been done before with semiconductor nanocrystals. “A lot of this came together from teamwork, I got a lot of really great suggestions from collaborators on how to collect and analyze this information. I used a suite of open source Python tools, which I was a little lost with until I met the researcher who developed them at a conference (Josh Taillon from NIST), who gave me some great suggestions and ideas” said Hammel. Using these advanced computer algorithms, they aligned and stacked hundreds of images on top of each other. Much like a long-exposure photograph of the night sky reveals stars the naked eye cannot see, this averaged stacked image revealed a detailed map of where the Gallium atoms were moving inside the nanocrystals. To the team’s knowledge, this signal-averaging approach for elemental mapping has not previously been applied to semiconductor nanocrystals.

The Gallium atoms rush in to claim “seats”, but not randomly. Gallium grabs the seats near the surface first. Because of the high surface-to-volume ratio of these tiny particles, this surface exchange causes a dramatic and rapid change in overall composition: within the first 15 minutes in the molten salt bath, the outside of the nanocrystals is substantially transformed. However, as the game goes on, it gets progressively harder. The Indium atoms sitting in the seats at the center of the nanocrystal are crowded in, and for a Gallium atom to reach the core, an Indium atom must fight its way out through an increasingly Gallium-rich lattice. This sets up a compositional gradient, essentially a smooth transition from a Gallium-rich exterior to an Indium-rich core, that persists even after 16 hours of reaction.

This new methodology, combining STEM with advanced computational image processing, is sensitive enough to detect and map the movement of atoms through individual nanocrystals. Applying it here directly revealed that the cation exchange process (Indium being replaced by Gallium) creates a graded composition rather than a simple sharp boundary between materials. The team also used computer simulations (finite element analysis in COMSOL) to model this exchange as a diffusion-limited process, finding that the rate of exchange slows dramatically as more Gallium enters the lattice, likely because the smaller Gallium atoms cause the lattice to contract, making it progressively harder for further exchange to occur.

Importantly, the methods developed in this work are broadly applicable and could be used to determine the elemental composition of many other types of nanocrystals that have previously been difficult to study due to their sensitivity to electron beams.

The ability to observe and better understand the cation exchange process in these semiconductor nanocrystals has significant implications for the development of next-generation materials. It has been suggested that graded compositions, like those observed here, could help suppress certain energy-loss processes in semiconductor devices, potentially enabling more efficient lighting and lower-power electronics. Whether these specific nanocrystals deliver on that promise remains an open and exciting research question, but this work provides the observational foundation needed to begin answering it. Additionally, the molten-salt synthesis approach that underpins this research is an active area of development as a potentially more versatile route to III–V semiconductor nanocrystals, materials that have historically been among the most challenging to synthesize with fine compositional control.

By developing new tools to better observe the game of "atomic musical chairs," the researchers are providing the field with insights into how to engineer materials at the atomic scale and revealing that the path from one material to another is more nuanced, and more interesting, than previously understood.

March 2026

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2026 Three Minute Thesis Finalists

Daniel Morton — Tue, 24 Feb 2026 20:57:33 +0000

2026 Three Minute Thesis Finalists Daniel Morton Tue, 02/24/2026 - 13:57

Daniel Morton

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��Ҵ�ý�ƽ�� 3MT Competition

2026 3MT Announcement

Recording of 2026 3MT Final

Meet 3MT Finalist Ben Hammel

Ben Hammel, a graduate student in the Dukovic Group, was a finalist in the 2026 ��Ҵ�ý�ƽ�� Three Minute Thesis Competition. We caught up with Ben to find out more about the whole 3MT process.

What is 3MT?

3MT stands for Three-Minute Thesis, which was a competition started at the University of Queensland. I think the history behind it is that they were going through droughts in Australia and everyone had these three-minute egg timers in their showers to limit water usage. Someone had this idea of maybe this was a good challenge for condensing/communicating your research: how well can you present your thesis in three minutes?

What did you have to do?

I came into this wanting to learn how to clearly describe my research. The rubric is really about explaining your science. They look at clarity, your enthusiasm, and about the slide and presentation. But they also look at can you describe the motivation of your research? Can you describe the design of your research? Can you describe the conclusions and societal impact of your work? So it is about science communication, with a strong grounding in the scientific aspects. Going through this process and thinking through these things has given me a better understanding of my own science.

Can you describe your research in five words?

Using microscope to look at nanocrystals. Six, that is ok, right?

What drew you to do the 3MT?

I wanted to improve my scientific communication skills, and I felt like there was something really cool about my research that I wanted to share. It is this simple idea that we need to look at nanocrystals to understand how they work. I get to use this amazing microscope to do just that!

What was the best part of the 3MT program?

The best part was definitely the cohort of talks. In the final competition folks got to see eleven presentations from across the graduate school, and that was awesome, but in the preliminary round there were more than 25. There were so many great talks from so many parts of the school that I got to see. It was really fun. You get to see in an hour so much condensed scientific knowledge. That was definitely the best part.

What was the worst/hardest part of the 3MT program?

The hardest part was talking about the science. It is so easy for me to say “we study these nanocrystals, and they’re cool, and I use this microscope”, but when people really ask me about what are the scientific questions you have and what are the experiments you run to answer them? And how are you going to engineer nanocrystals? It’s difficult to answer these kinds of technical questions in an accessible way.

How do you think your experience in 3MT will help you in the future?

Oh, it’s already helping me! Just in the way I talk to people and explain things. I feel like it has made me intellectually stronger and I am already noticing that it helps me communicate more clearly and think about my research in different ways.

What would you say to a grad student considering doing 3MT in the future?

Strongly recommend. It will take up a decent amount of your time, but it is definitely worth it. Don’t be afraid to tackle hard scientific concepts! One thing I regret not doing more of is really trying hard to tackle quantum mechanics in my talk. The properties of quantum dots are derived from quantum mechanics and I was scared to try to explain that, and I made my explanation totally classical. I was describing electricity flowing through crystals, but I think that people were hungry to learn more about the deeper science, and I should have given it a shot, at least to practice it and see if I could do it.

February 2026

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Structural and Compositional Evolution of Colloidal In1–xGaxP1–yAsy Nanocrystals during Cation Exchange Revealed by Electron Microscopy

Daniel Morton — Fri, 13 Feb 2026 18:11:18 +0000

Structural and Compositional Evolution of Colloidal In1–xGaxP1–yAsy Nanocrystals during Cation Exchange Revealed by Electron Microscopy Daniel Morton Fri, 02/13/2026 - 11:11

ACS NANO, 2026, 20, 7, 5506-5517

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Influence of Ligand Exchange on Single Particle Properties of Cesium Lead Bromide Quantum Dots

Daniel Morton — Tue, 20 Jan 2026 21:16:48 +0000

Influence of Ligand Exchange on Single Particle Properties of Cesium Lead Bromide Quantum Dots Daniel Morton Tue, 01/20/2026 - 14:16

CHEMISTRY OF MATERIALS, 2026, 38, 3, 1074-1083

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New ‘Molecular Dam’ Stops Energy Leaks in Nanocrystals

Daniel Morton — Tue, 21 Oct 2025 19:17:19 +0000

New ‘Molecular Dam’ Stops Energy Leaks in Nanocrystals Daniel Morton Tue, 10/21/2025 - 13:17

Daniel Morton

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A molecular engineering breakthrough could make key light-driven reactions over 40 times more efficient.

A collaborative team of scientists from the University of Colorado Boulder, the University of California Irvine, and Fort Lewis College, led by RASEI Fellow Gordana Dukovic, has found a way to slow energy leaks that have impeded the use of tiny nanocrystals in light-driven chemical and energy applications. As described in a new article published in the journal Chem, the team has used a molecule that strongly binds to the nanocrystal’s surface, essentially acting like a ‘dam’ to hold back the energy stored in the charge-separated state formed after light absorption. This technique extends the lifetime of the charge separation to the longest recorded for these materials, providing a pathway to improved efficiencies and more opportunities to put this energy to work in chemical reactions. This collaboration is part of the U.S. Department of Energy funded Energy Frontier Research Center: Ensembles of Photosynthetic Nanoreactors (EPN).

Harnessing Light to Power Chemistry

Many of the products we rely on today, from plastics, to fertilizers, and pharmaceuticals, are created, or synthesized, through industrial chemical reactions that can often require immense heat and pressure, typically generated by burning fossil fuels. For decades there has been research exploring a less harsh and theoretically more efficient alternative: Photocatalysis. The goal is to use a compound, a “photocatalyst”, that can harness the energy in light and use it to power chemical reactions at room temperature. Semiconductor nanocrystals, particles that are over a thousand times smaller than the width of a human hair, are a leading candidate for this job. When exposed to light these nanocrystals generate a short-lived spark of energy, in the form of a separated negative charge (an electron) and a positive charge (called a “hole”, due to the absence of an electron). A key challenge in this area is that this spark disappears quickly, because the electron and the hole recombine, and the energy is lost before it can be put to good use.

Building a Molecular Dam

To solve this problem the team focused on building what we might call a ‘molecular dam’, something that helps prevent, or at least slow down, the electron and the hole from recombining. This research started with cadmium sulfide (CdS) nanocrystals and designed a molecule (in this case a phenothiazine derivative) with two key features; first the incorporation of a chemical group that acts as a ‘sticky anchor’ (in this case a carboxylate group), which binds strongly to the nanocrystal surface, and second, a molecular structure that quickly accepts the positive charge (the hole), from the nanocrystal to realize the light-driven charge separation event.

By anchoring this molecule to the surface of the nanocrystal the team created a highly efficient and stable pathway. As soon as exposure to light creates the electron-hole pair in the nanocrystal, the anchored molecule shuttles the hole away, physically separating it from the electron. This physical separation of the electron and the hole prevents the two from quickly snapping back together and wasting the energy. This results in a charge-separated state that lasts for microseconds, which is an eternity in the world of photochemistry, creating a much larger window of time for future researchers to work with in terms of harnessing this captured light-driven energy for useful chemical reactions. The team was able to prove the significance of the ‘sticky anchor’ carboxylate, by comparing their derivative to a phenothiazine that lacked the anchor, which was shown to be far less effective at holding the energy, demonstrating that this anchoring to the surface was key to this system’s performance.

This collaborative work was done as part of the U.S. Department of Energy funded Energy Frontier Research Center (EFRC) Ensembles of Photosynthetic Nanoreactors (EPN). EPN consists of 17 senior investigates located across 9 universities and 3 U.S. national laboratories. The goal of EPN is to provide a forum for collaboration, bringing together expertise to advance the frontiers of discovery and fundamental knowledge in photochemical energy conversion. The aim is to not only foster new discoveries and applications, but in doing so, train the researchers who will build knowledge and advances that will benefit the United States innovation and economy.

This project took advantage of the different areas of expertise of each team to generate ideas and quickly execute them. Kenny Miller’s group of dedicated undergraduate researchers at Fort Lewis College synthesized the carboxylated phenothiazine derivative (and a slew of others). Miller then sent the derivative to Jenny Yang’s group of inorganic electrochemists at UC Irvine for advanced electrochemical characterization. Gordana Dukovic’s group here at ��Ҵ�ý�ƽ�� synthesized the nanocrystals, tested their compatibility with the derivative, characterized the binding, and undertook the advanced laser spectroscopy study to see how the electrons and holes behaved.

“The first time I saw the results-saw how effective our ‘molecular dam’ was at slowing charge recombination-I knew we had struck gold” explained Dr. Sophia Click, a lead author on the study. “To slow charge recombination from nanoseconds to microseconds, and with a molecule that can be paired with so many existing photocatalyst systems, makes this work vital to share with as many researchers as possible.”

Development of this ‘molecular dam’ could have implications for the future design of catalysts for light-driven chemistry. By increasing the efficiency of the initial energy-capture step, this system improves the efficiency of the entire process. This could improve not just one specific reaction, but rather, benefit a broad range of light-driven chemical reactions. A key technology this could enhance is the development of light-driven creation of chemical commodities or high-value chemicals. This research provides a more robust and versatile chemical toolkit for exploring these possibilities.

This discovery in controlling charge-separation, and energy, at the nanoscale is an important design parameter into developing light-driven chemistry, and hopefully light-driven chemical manufacturing. Imagine a future where materials, such as plastics, and even pharmaceuticals, are not made in energy inefficient high-temperature reactors powered by fossil fuels but instead are synthesized directly and efficiently using the power of light. While this vision is still on the horizon, the work done in this collaboration provides an important piece of the scientific puzzle, constituting a huge leap toward one day achieving these goals.

The study, “Exceptionally Long-Lived Charge Separated States in CdS Nanocrystals with a Covalently Bound Phenothiazine Derivative” was published in the journal Chem. This work was supported by the U.S. Department of Energy, Office of Science, as part of the Energy Frontier Research Center: Ensembles of Photosynthetic Nanoreactors (EPN; DE-SC0023431), with additional experiments on nanorods supported by Air Force Office of Scientific Research under AFOSR (FA9550-22-1-0347).

October 2025

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Exceptionally long-lived charge-separated states in CdS nanocrystals with a covalently bound phenothiazine derivative

Daniel Morton — Mon, 13 Oct 2025 23:35:33 +0000

Exceptionally long-lived charge-separated states in CdS nanocrystals with a covalently bound phenothiazine derivative Daniel Morton Mon, 10/13/2025 - 17:35

CHEM, 2025, 102760
October 2025

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Unlocking a Cleaner Way to Do Chemistry

Daniel Morton — Tue, 30 Sep 2025 15:11:48 +0000

Unlocking a Cleaner Way to Do Chemistry Daniel Morton Tue, 09/30/2025 - 09:11

Daniel Morton

Taking the heat out of chemical manufacturing

For nearly two centuries chemists have relied on a simple principle when building molecules and materials: to make something new you have to apply energy, sometimes in the form of chemical energy, but most often in the form of heat.

From producing plastics to creating life-saving medicines, many of the chemical reactions that form the foundation of our modern world are driven by thermal energy, often generated by burning fossil fuels. This approach, while effective, is often incredibly energy-intensive and can lead to a host of other issues, from unwanted byproducts to a large carbon footprint. In essence it is like using a sledgehammer to build a delicate piece of furniture, while it might get the pieces together, it’s inefficient, causes unnecessary damage, and creates a lot of waste in the process.

But what if there was a better way? What if we could take the heat out of chemical manufacturing and use a more precise, sustainable energy source?

RASEI fellows are part of a growing wave of research that is doing just that by using light to drive chemical transformations. This isn’t about using light to just heat things up, it’s about harnessing the specific energy of photons to activate molecules in a targeted and efficient way. This approach, known as photocatalysis, is unlocking a cleaner, more controlled way to build the molecules we need. It is poised to transform everything from the creation of pharmaceuticals to the development of new and sustainable materials and plastics.

The shift to light-driven chemistry is not merely an academic exercise; it is a critical step toward a more sustainable and efficient industrial future. RASEI researchers, working across a range of national collaborations, have published more than 15 research papers in the past year, reflecting their commitment to innovation in this space. The research approaches the problem from a range of perspectives, exploring new chemical pathways and understanding the factors that control the efficiencies of these reacting.

The benefits of collaborative research the brings together a range of approaches to solve problems together is well illustrated in this roundup of recent research, including highlights from some large national collaborations, including contributions from U.S. Department of Energy funded Energy Frontier Research Centers (the Bio-inspired Light-Escalated Chemistry Center (BioLEC) and the Ensembles of Photosynthetic Nanoreactors (EPN)), and a National Science Foundation funded Center for Chemical Innovation (The Center for Sustainable Photoredox Catalysis (SuPRCat))

The summaries that follow provide a glimpse into this exciting work, detailing some of our latest discoveries and describing some of the tangible ways we are using light to create cleaner, more effective, and sustainable chemical processes.

Recent Research Highlights

Shining new light on an old problem: Breaking down ‘Forever Chemicals’ and building the next generation of materials

DOI: https://doi.org/10.1038/s41586-024-08327-7

Using a new catalyst and visible light, researchers have developed a chemical “scalpel” to degrade persistent pollutants and enable new, more precise chemical reactions.

The global challenge of “forever chemicals” has made the headlines for years. The carbon-fluorine (C–F) bond is one of the strongest in all of chemistry. For decades the sheer strength of the C–F bond has been a blessing and a curse. This incredible strength is what makes “forever chemicals”, like PFAS, so stable and useful in everything from non-stick pans to waterproof clothing but is also the reason that they are nearly impossible to break down. This has been a major contributor to the growing plastic waste crisis, and a key reasons for these compounds to be now known as one of the hardest pollutants to remove from the environment. A recent collaborative study, including RASEI Fellow Niels Damrauer, has a new solution for this problem. Development of a new catalyst that acts like a chemical scalpel, using blue light to precisely sever this famously inert bond. This approach not only offers a new way to degrade these persistent pollutants but also opens the door to using what were previously considered unreactive fluorinated molecules as building blocks for new chemical transformations and products.

This study is an illustrative example of a modern, collaborative approach to chemical innovation, as part of the NSF funded Center for Sustainable Photoredox Catalysis (SuPRCat). The research team came at the problem from two different angles: computational modeling and hands-on experimentation. The computational chemists first used powerful simulations to design and predict the behavior of a new organic catalyst. This helped them understand exactly how the catalyst could use low-energy, visible blue light to act as our "chemical scalpel," targeting and breaking the C–F bonds without the need for intense heat.

With this knowledge, the experimental chemists then created the catalyst in the lab. They showed that it could precisely snip the C-F bonds in a variety of molecules, demonstrating it was capable of both degrading persistent pollutants like PFAS and building new chemical structures that were previously difficult to construct.

The success of this research with a simple, abundant energy source like visible light shows that chemical reactions don’t have to be energy intensive. This research describes the power of precise, light-driven chemistry. By designing a catalyst that can target and activate some of the toughest bonds in chemistry, this team has not only revealed a potential path forward for degrading PFAS, but also demonstrated a new tool for chemists to build molecules in a cleaner and more energy efficient way.

A Chemical Blueprint for Turning Sunlight and Carbon Dioxide into Fuel

DOI: https://doi.org/10.1021/acsmaterialsau.5c00010

Combining computational design and experimental research, scientists have engineered a well-aligned connection between two materials, creating a more efficient pathway for clean energy.

The search to create carbon-neutral fuels from sunlight and carbon dioxide (CO₂) is one of the most exciting frontiers in sustainable energy. However, it is not enough to simply find a catalyst that can do the job, the real challenge lies in designing a system where all the components work in harmony. Imagine having two brilliant devices that are designed to work together, but they just can’t quite “talk” to each other. One is an incredible light sensitive material that captures sunlight, and the other is a special catalyst that can turn CO₂ into fuel. Previous research has found that when you bring these two components together their electronic energies were mismatched, causing poor ‘communication’ between the components, leading to the overall system being inefficient. Research led by RASEI Fellow Nate Neale uses a combination of advanced computational modeling and sophisticated experimentation to engineer an aligned electronic “bridge” to better connect the two materials, revealing a more efficient communication pathway, and hence a more effective overall system.

To solve the energy mismatch between the components the team adopted a feedback loop between computational modeling and experimentation. Powerful computational tools enabled the design of a range of potential linking molecules to explore how they would influence the electronic coupling between the silicon nanocrystal (the solar panel) and the catalyst. This approach acted as a “chemical blueprint”, allowing them to predict which design would create the most well-aligned connection. The team then took these findings to the lab and synthesized the most promising candidates and tested their real-world performance, comparing them to the properties predicted by the models. The results confirmed the predications and demonstrated that a specific, directly bonded molecular bridge was the most effective design.

This work describes a foundational step in the search for fuels synthesized by light. By developing an approach for the fundamental challenge of aligning a solar collector and a CO₂ catalyst, the team has provided a critical design guideline for building more efficient and powerful devices in the future.

Supercharging Chemistry: A jump forward in light-driven chemistry

DOI: https://doi.org/10.1126/science.adw1648

New collaborative research involving RASEI Fellow Niels Damrauer, addresses one of the ‘house of cards’ problems sometimes critical in photoredox catalysis.

Think about how you build a house of cards, every time you add a new card, there is a chance the whole thing will fall apart. This is a challenge often faced by chemists when they are trying to put together the components needed for a light-driven reaction. While this type of chemistry has huge potential in making the chemistry cleaner and more efficient, one of the features that can cause the whole thing to fall apart is a phenomenon called back electron transfer, where the desired chemical reaction is reversed, wasting energy and limiting the kinds of reaction that can be performed.

This collaborative team that includes RASEI Fellow Niels Damrauer from ��Ҵ�ý�ƽ�� and the groups of Garret Miyake and Robert Paton from Colorado State University in Fort Collins, has developed a new catalyst system that overcomes this fundamental obstacle. Published in a recent issue of Science, this work introduces a ‘super-reducing’ organic photoredox catalyst that, through preventing this backward reaction, opens the door to powerful new redox chemistries.

To better understand this discovery it is useful to think of the process like filling a bucket with water. In typical photoredox reactions, the bucket has a leak. As water is poured into the bucket (adding energy from light), some of it immediately drains out. This ‘leak’ is back electron transfer (BET), and it is especially problematic for complex and difficult reactions that require a lot of energy – it is like trying to fill a very leaky bucket with a very slow faucet.

The research collaboration, part of the National Science Foundation (NSF) funded Center for Chemical Innovation (CCI) Center for Sustainable Photoredox Catalysis (SuPRCat) took inspiration from nature to develop a solution for this problem. In photosynthesis plants use a process called proton-coupled electron transfer (PCET) to efficiently capture and store energy from sunlight, preventing energy loss. The team used a combination of sophisticated computational modeling and experimental investigation to design a catalyst that incorporates a similar mechanism. When the catalyst is energized by light it simultaneously transfers an electron to the target molecule and releases a proton (a hydrogen atom without its electron). This prevents the reaction from going backwards. This small change has a huge impact on how the reaction proceeds, it is essentially like patching the leak in the bucket as you pour the water in, ensuring that all the energy is used for the desired reaction.

As is often the case with research, the path to this discovery was not a straight line. The investigations initially focused on changing an existing catalyst framework. During these experiments they noticed that one of the new catalysts (PC40Me) was unexpectedly effective. The reduction of benzene is known to be a difficult transformation, but reactions catalyzed with PC40Me were possible. They found that under the reaction conditions PC40Me was transforming into a new chemical structure, and it was this new system that was efficient for the historically difficult reduction of benzene. Armed with this knowledge the team built new catalyst designs around the new structure, creating a more efficient catalyst (named PC8). PC8 is not only a ‘super reducer’ capable of reducing a broad range of aromatic compounds under mild conditions, it also proved to be extremely robust.

The key features of this work lies in its potential to be a new tool in how we design and build everything from pharmaceuticals to plastics. By providing a way to perform these difficult reduction reactions more efficiently and sustainably, this catalyst system has the potential to reduce waste and energy consumption. By opening the door to a transformation that has typically been thought of as difficult and un-efficient, it could act as an enabling technology in the synthesis of new classes of molecules that were previously out of reach.

This work highlights the power of collaboration. The combination of different tools and approaches that were required to complete this work would have been prohibitive for a single research group. By combining expertise the team were able to unravel this complex chemical puzzle, not only demonstrating a new transformation, but providing some design rules that can be used by future photocatalysis practitioners in reducing BET.

Finding the On switch for more efficient light-driven chemistry

DOI: https://doi.org/10.1038/s41467-025-60729-x

Collaboration led by RASEI members Obadiah Reid and Garry Rumbles solves a long-standing puzzle in important organic chemical transformation.

In the world of organic chemistry, making new molecules, the building blocks for everything from advanced electronic materials to pharmaceuticals, is a bit like being a chef. Chemists are always looking to improve the recipe, to make it faster, cheaper, more efficient, and produce less waste. In recent years one of the most exciting new ‘cooking techniques’ is nickel photocatalysis, which uses abundant, low-cost nickel and the power of light to enable chemists to build complex molecules under mild conditions.

This technique has emerged as something of a game-changer in building molecules, but it comes with a significant puzzle. The nickel catalyst, as it is normally added to a reaction, is in a dormant state (called a ‘pre-catalyst’). To get the reaction moving, the catalyst needs to be ‘woken up’. For years, scientists were not sure what the wake-up call was. The activation from pre-catalyst to the functioning catalyst was something of a black box, with numerous theories for what was happening. This led to the assumption that each reaction was unique, and each reaction required its own individual and complicated startup sequence. This has often required a lot of work to find the right ‘On switch’.

This collaborative study, led by RASEI researchers Obadiah Reid and Garry Rumbles at the National Renewable Energy Laboratory (NREL), brings together expertise from the SLAC National Accelerator Laboratory, Brookhaven National Laboratory, Argonne National Laboratory and Northeastern University. Together, the scientists have identified key features of the transformation from pre-catalyst to active catalyst. In the report, just published in Nature Communications, the team shows that there is a universal ‘On switch’ to start these powerful reactions, and the key to this transformation is light.

Imagine a high-tech machine delivered in a locked crate. You know that once you get it out and get it running, it can do amazing things, but you don’t have the key. For years, chemists were essentially trying to pick the lock in different ways every time they wanted to use it. This study describes a universal key for getting the crate open.

It was found that light, either directly, or transferred from another light-absorbing molecule, provide a jolt of energy that breaks a bond in the nickel pre-catalyst structure. This process, which is called photolysis, activates the nickel complex, getting it ready to do the chemistry. This initial step is something that has previously been proposed but never fully proven.

The team brought together a sophisticated array of tools to effectively investigate this mechanism, including incredibly fast laser systems that can watch chemical changes happen in fractions of a second. This allowed them to witness the ‘unlocking’ process in real-time and identify the exact sequence of events. They observed that after the initial light-induced bond breaking, the catalyst can then interact with molecules in the surrounding solvent, forming a temporary ‘reservoir’ that holds the catalyst in a state ready for the main reaction.

Building this body of evidence and developing these findings required a significant team effort, bringing together scientists from across the country, from multiple national labs and universities. RASEI Scientists at ��Ҵ�ý�ƽ�� and NREL used advanced spectroscopy to track the catalyst’s behavior, while researchers at SLAC used high-powered X-rays to confirm changes in the structure of the nickel complex. This combination of knowledge and experience with cutting-edge instrumentation was essential in providing a complete understanding of these reactions begin.

Development of unified explanation for how one of the most important tools in an organic chemist’s toolbox is activated has important implications. Understanding this fundamental activation step allows chemists to move from guessing to designing. Not only does this support improvement in the activation of existing reactions, it also provides opportunities to design new transformations, all of which will streamline the manufacture of chemical commodities, such as pharmaceuticals and materials.

Scientists move microscopic solar chemical factories out of water to unlock new transformations

DOI: https://doi.org/10.1039/D5SE00263J

Four RASEI Fellows work together to expand the potential applications of nanoparticle photocatalysts

We all understand the power of the sun. We feel it on a hot summer’s day, we see it harnessed in solar panels that power our homes and cities. Chemical photocatalysis develops approaches to shrink that ability to harness this energy down to a molecular scale, and uses this energy to power chemical reaction, to power the building of important organic molecules, the foundations of pharmaceuticals, materials, and clean fuels.

One of the technologies used to harness light on the molecular level are a class of particles called organic nanoparticles (oNPs). Think of them as tiny, solar-powered factories, expertly designed to capture light and use its energy to drive chemical reactions. The oNPs are made from readily available earth-abundant materials, offering a cheap, clean, and sustainable alternative to a range of more traditional chemical reactions, which can often rely on rare, expensive metals that are hard to get hold of and can produce significant waste.

However, the oNPs, for all their potential as chemical factories, do have one significant limitation, they can only be built and operated in water. This is a fundamental roadblock. While water is essential for life, it is often a very poor environment for performing chemical reactions and can be very detrimental for the complex and delicate sequence of chemical transformations required for producing valuable products. The full power of these nano-factories was, quite literally, stuck in the water.

To understand this challenge, imagine that you have designed the world’s most efficient and powerful engine. It is a true engineering breakthrough, but it comes with a major catch, it can only run while completely submerged in the ocean. This is fine if you want to get around in a submarine, or a boat, but you can’t put it into a car, or a plane, or a generator on land, where you need it most. The potential of this new innovation is trapped, unable to be used for countless valuable applications.

That is similar to the situation faced by the researchers, led by RASEI Fellows Stephen Barlow, Seth Marder, Obadiah Reid and Garry Rumbles. The oNPs were confined to water-based reaction media, in order to realize their full potential the team needed to find a way to move these delicate ‘nano-factories’ from water to the ‘dry-land’ of other chemical environments, known as non-aqueous solvents, without the oNPs collapsing or breaking down.

This study describes a solution that the team developed. They devised a multi-step process to gently coax the oNPs out of their native water environment and prepare them to operate in different chemical solvents.

The process they developed is analogous to making salad dressing in the kitchen. It begins by mixing the water containing the nanoparticles with an oily substance (in this study oleic acid) and shaking it. This creates an emulsion, where tiny droplets of water are suspended in the oil, much like a vinaigrette. During this process the oNPs leave the water and move into the oil, which wraps around them like a protective coating. Finally the water is gently remove, leaving the oNPs safely suspended in their new oily environment. The protective layer formed around them allows them to be seamlessly transferred to a range of new non-aqueous solvents, ready to get to work.

A key part of this study was demonstrating that the oNP ‘factories’ were still functional after their transfer to new solvent systems. Using a suite of tools the team were able to confirm that the transferred oNPs could still absorb light and perform the chemical reactions.

With these findings the potential of the oNPs can be explored and expanded. It reveals new opportunities, not only in putting together organic molecules, but also in the synthesis of clean fuels, such as hydrogen.

September 2025

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c-ALD-Grown Metal Oxide Shell Enables Distance-Independent Triplet Energy Transfer from Quantum Dots to Molecular Dyes

Daniel Morton — Fri, 15 Aug 2025 01:49:36 +0000

c-ALD-Grown Metal Oxide Shell Enables Distance-Independent Triplet Energy Transfer from Quantum Dots to Molecular Dyes Daniel Morton Thu, 08/14/2025 - 19:49

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, 147, 34, 31409-31416

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Pre-steady-state kinetics of nanocrystal:molybdenum nitrogenase biohybrids reveals hole-scavenging efficiency is critical to N2 reduction

Daniel Morton — Wed, 30 Jul 2025 19:59:40 +0000

Pre-steady-state kinetics of nanocrystal:molybdenum nitrogenase biohybrids reveals hole-scavenging efficiency is critical to N2 reduction Daniel Morton Wed, 07/30/2025 - 13:59

CELL REPORTS PHYSICAL SCIENCE, 2025, 102732

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Understanding light-driven production of hydrogen could unlock future insights for harnessing light for chemistry

Daniel Morton — Mon, 09 Jun 2025 16:27:04 +0000

Understanding light-driven production of hydrogen could unlock future insights for harnessing light for chemistry Daniel Morton Mon, 06/09/2025 - 10:27

Daniel Morton

Light to fuel: clean hydrogen production. Improved understanding of the light-driven production of hydrogen holds the promise not just to make the reaction more efficient in producing a fuel, but also to offer a framework to better understand future light-driven chemistries.

Many chemical reactions require the input of energy to activate the transformation. This can often be in the form of heat, or chemical energy. One of the most efficient ways of introducing energy into a reaction is by using light. If you don’t have to heat up a reaction, or add extra chemicals to it, and instead shine a light on it, you can save significant energy. However, it can be difficult to control and optimize light-driven reactions. This research, just published in Chem, is a collaboration between the Dukovic Group at the University of Colorado Boulder (��Ҵ�ý�ƽ��) and the King Group at the National Renewable Energy Lab (NREL) and provides a holistic understanding of the light-driven production of hydrogen gas using a nanocrystal-enzyme complex as the catalyst, and a computational framework that can be used more generally to understand other light-driven chemical reactions in the future. The code for this model is being made available in the supplementary documents of this article.

Chemical catalysis is a special type of reaction, one that increases the speed of a transformation and often reduces the amount of waste produced by the process. Think of it like an assembly line. The catalyst is like a station on the line, bringing together two or more components to create a new product that is then passed along. Without the catalyst the components might, by chance, bump together and form the desired product, but it will be much slower, and much less frequent. The catalyst remains unchanged in the process and can repeat the transformation many times.

Enzymes are Nature’s catalysts. On the cellular level, whenever a change needs to happen, an enzyme is usually involved. The speed of an enzyme, and its selectivity, that is its ability to only react with the desired molecules out of the soup of molecules present in a typical cell, is fantastic. Enzymes are often superior to catalysts we can make in a lab, and as such, much research has gone into finding ways to harness such enzymes to do reactions for us in the lab. Unfortunately, it is not as easy as just grabbing some enzyme out of a cell. Enzymes often require specific environments and partners to react with.

Redox enzymes are a special, and particularly attractive, class of enzymes. They are capable of adding, or removing, an electron from a chemical reaction, a key step in the production of hydrogen gas. Redox enzymes rarely exist by themselves. Returning to the assembly line analogy, to get a station that can add the electrons to the protons (H⁺) to make hydrogen gas, many other stations need to be added before in a specific order. In a cell there is a chain of enzymes that pass the electrons along before the reaction can take place.

This is where the artificial component comes in. The nanocrystal, which, when exposed to light, releases an electron, replaces the long chain of enzymes and can directly transfer an electron to the enzyme. So, you reduce your assembly line down from a chain of many stations to just two. “This work was really only possible through collaboration” explains Gordana Dukovic, the lead researcher at ��Ҵ�ý�ƽ��. “The team at NREL have vast expertise in hydrogenase (the redox enzyme that creates hydrogen gas), and we have the expertise in making and tailoring the nanocrystals and studying what they do after they absorb light”. Getting the enzyme to work with the artificial electron donor took some work.

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This Research

Characterization of Photochemical Processes

Electron Transfer Kinetics

Competition between electron transfer processes

Activation Thermodynamics

Role of Surface-Capping Ligands

Quantum Efficiency of Charge Transfer

2020 Review of this research area

The two teams first started working together in 2011 and have invested a great deal of work in understanding many aspects of this nanocrystal-enzyme hybrid. “Working with the team at NREL has been really amazing” says Dukovic, “the opportunity to work with experts who really help you ask the important questions, and identify where our assumptions were wrong, was essential for this work.” For over more than a decade this collaboration has interrogated the different steps of this process, such as how the nanocrystal and enzyme fit together, how the nanocrystal generates an electron when exposed to light, how the nanocrystal transfers the electron to the enzyme, and how the enzyme uses those electrons to make hydrogen. It is only through building this comprehensive understanding of the steps that underpin this reaction that the team are in the position to provide a holistic picture of the whole transformation. Furthermore, the framework that they have built is robust enough to be applied in improving other light-driven reactions in the future.

This work describes an improved assembly line capable of converting light energy into hydrogen gas, a clean burning fuel that provides new, more efficient ways, to generate electricity. Perhaps more excitingly, it demonstrates the power of a new computational model and framework, built on over a decade of collaborative research, which has been made freely available, that provides insights into light-driven reactions and can be used by the scientific community to refine and optimize future light-driven chemistry. Helena Keller, the lead author is enthusiastic about the next steps “We are in a really exciting place now, where the capabilities of using computational methods to understand complex systems like this are becoming more and more accessible. The better we understand how to control processes at the smallest scales – like at the level of individual electron transfers – the closer we get to revolutionizing the way we produce energy and materials for the good of the world”.

JUNE 2025

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