More Brain-like Computers Could Cut IT Energy Costs

The dynamics of magnetic metamaterials offer a path to low-energy, next-gen computing

The public launch of OpenAI’s ChatGPT in November 2022 caused a media sensation and kicked off a rapid proliferation of similar Large Language Models (LLMs). However, the computing power needed to train and run these LLMs and other artificial intelligence (AI) systems is colossal, and the energy requirements are staggering. Training the GPT-3 model behind ChatGPT, for example, required 355 years of single-processor computing time and consumed 284,000 kWh of energy1. This is one example of a task that the human brain handles much more efficiently than a traditional computer, and researchers are investigating the potential of more brain-like (neuromorphic) computing methods that may prove to be more energy efficient. Physical reservoir computing is one such method, using the natural, complex responses of materials to perform challenging computations. Researchers from the University of Sheffield are investigating the use of magnetic metamaterials – structured at the nanoscale to exhibit complex and emergent properties – to perform such computations. In work recently published in Communications Physics, they have demonstrated an ability to tune the system to achieve state-of-the-art performance in different types of computation. Their results show that an array of interconnected magnetic nanorings is a promising architecture for neuromorphic computing systems.

Emergence Could Power More Brain-Like Computers

Anyone who has witnessed the majestic and mesmerising flight of a murmuration of starlings has no doubt wondered how a flock of birds can achieve such synchronised behaviour. This is an example of emergence, where the interactions of simple things lead to complex collective behaviours. But emergence doesn’t only occur in the natural world, and a group at the University of Sheffield is investigating how the emergent behaviour can be engineered in magnetic materials when they are patterned to have nanoscale dimensions.

Dr Tom Hayward, Senior Lecturer in Materials Physics at the University of Sheffield and author of this paper says,

Life is inherently emergent – with simple entities connecting together to give complex behaviours that a single element would not have. It’s exciting because we can take simple things – which hypothetically can be very energy efficient – and make them manifest the kind of complexity we see in the brain. Material computation relies on the fact that many materials that exhibit some form of memory can take an input and transform it into a different output – precisely the properties we need to perform computation. Our system connects a series of tiny magnetic rings into a big ensemble. One individual ring in isolation shows quite simple behaviours. But when we connect them, they interact with each other to give complex behaviours.

Magnets have a number of properties that make them interesting for these kinds of applications: 

  • Firstly, they are non-volatile, with inherent memory – if you stick a magnet to your fridge, it stays put.
  • Brains (and brain-like computers) need to have non-linear responses, taking simple information and performing complicated transforms, and that’s something magnets are naturally good at.
  • There are plenty of ways to make magnets change state and perform computations that use very little energy.
  • And magnets are a well-established technology (used, for example, in hard drives and Magnetoresistive random-access memory (MRAM)), and so there are existing routes to technology integration.

XPEEM Highlights the Underlying Magnetic Dynamics

Key to this research is understanding what’s happening to these magnetic nanorings when they’re connected together – the way that emergence changes the way they change magnetic states.

Read more on Diamond website

Stanford study shows how modifying enzymes’ electric fields boosts their speed

A seemingly subtle swap of metals—substituting a zinc ion with a cobalt ion—and a mutation ramps up the overall electric field strength at the active site of an enzyme, Stanford scientists find. The result is a predictably modified enzyme that works an astonishing 50 times faster than its unmodified analog.

Stanford researchers have demonstrated a way to dramatically speed up the reaction rate of an enzyme, a finding that could pave the way to designing ultra-fast synthetic enzymes for a range of industrial and medical uses.

Honed over billions of years of evolution, biological enzymes are marvels of chemistry. These specialized proteins serve as catalysts for accelerating chemical reactions essential to life as well as processes used in the food, pharmaceutical, and cosmetic industries.    

Ever since enzymes’ discovery nearly two centuries ago, scientists have sought ways to make them even faster. Most fabricated enzymes, though, have failed to match the lofty efficiency standards of nature-made varieties. And even where some successes have been realized through directed evolution, a protein engineering method that mirrors nature’s trial-and-error approach, these successes so far have been by chance, not because of a deeper understanding of how enzymes work or could be modified to work more swiftly.

Now, in a new study, researchers at Stanford’s School of Humanities and Sciences and SLAC National Accelerator Laboratory have debuted a modified enzyme that works an astonishing 50 times faster than its unmodified analog. The findings derive from pioneering research at the university regarding electric fields generated at “active sites,” the pocketlike places where revved up chemical reactions occur. Based on this concept, the researchers tweaked the chemistry of the active site, boosting its electric field strength and specificity to deliver the zippy results.  

Read more on Stanford University website

Image: X-ray crystallography was used to investigate and compare the 3D crystal structures of the unmodified enzyme containing an ion of zinc (Zn) (pictured left) and the modified enzyme with a cobalt (Co) ion in place of zinc (pictured right).

CSIC-supported new dedicated ALBA laboratory opens to drive sustainable energy solutions

The ALBA Synchrotron Light Source and the Institute of Materials Science of Barcelona (ICMAB-CSIC) have opened a new laboratory at ALBA with the aim to enhance studies in the field of battery research and high temperature superconducting tape developments. The new facility enables users of ALBA, including the important community of CSIC researchers, to significantly optimize experiments involving synchrotron light. The project was jointly funded by the CSIC PTI+ TransEner, funded by the European NextGeneration funds and the Recovery, Transformation and Resilience Plan and ALBA.

Cerdanyola del Vallès (Barcelona), 24th October 2023. In the current landscape of global challenges, the progress in creating and testing innovative materials and technologies, enabling sustainable green energy ecosystems, is crucial for moving toward a green and resilient economy. In particular, the development of reliable, safe and affordable batteries, based on abundant and low-cost elements, is essential for key necessities of our modern society, including advancing electro mobility, energy storage for grid applications, and Internet of Things applications. Additionally, advances in manufacturing high-temperature superconducting tapes hold promise for the energy sector, with applications including power lines, wind energy, and aeronautics, and even in the utilization of fusion energy.

ALBA and ICMAB-CSIC have teamed up to create and commission a laboratory infrastructure, allowing ALBA’s user community in the field of energy storage to prepare, test and optimize their samples directly at ALBA’s premises. This initiative was funded by the CSIC PTI+ TransEner initiative and ALBA. This is particularly beneficial for Spanish and international research teams that are not based in Barcelona area but also benefits the highly complex development of local groups in the area of superconductive cable developments.

The new laboratory has two specialization parts, both devoted to finding greener energy applications in relevant industrial sectors. One is aimed at producing high-throughput samples of superconducting tapes and the second one is for developing batteries, in order to analyze them under in situ (real-time observation) and operando (in operation) conditions using synchrotron-based characterization techniques.

Read more on Alba website

#EBSstory How can iron in the moon and meteorites help to understand the origin of the Solar System?

Using ESRF-EBS, s​​​​​​cientists from Leibniz University Hannover are investigating the origins of the Solar System by studying samples from the moon and micrometeorites.

Meteorites are remnants of material from the early solar system. Our Earth accumulates on average 100 tons per day of these extraterrestrial samples, which largely exhibit spherical shapes. The presence of iron in them provides insights into the formation and composition of the solar system.

Equally, detecting the different forms of iron in moon samples can shed light on the geology of the moon, its history and how celestial bodies form in our solar system.

Regarding the moon, after the Apollo mission, back in the 70s scientists studied several samples and found that iron was very scarce. However, recent studies have found that iron and other metals are more abundant in certain zones in the moon, notably the darker zones, than in the Earth. This effectively disputes the hypothesis that the moon’s metal comes from the Earth’s debris after it collided with a Mars-sized planet called Theia, 4.5 billion years ago.

“Iron in the moon is a very valuable resource as it can be used to construct infrastructure and equipment, for example in the case of a potential lunar space station to carry out research”, explains Franz Renz, professor at Leibniz University Hannover (LUH) and leader of the team.

The team came to the ESRF with samples from both the moon and meteorites. They used the technique of Synchrotron Mössbauer Source to characterise the iron-rich microscopic meteorites, of a diameter of around 100 microns on average, collected from an up to 3.8-million-year-old continuous sedimentary record in the Atacama Desert in Chile. Because this desert is the oldest and driest temperate desert on Earth, it preserves the samples in optimal condition to monitor changes in flux, types and composition of extraterrestrial material over time.

Read more on ESRF website

Image: Lunar samples.

Credit: F. Renz.

NSRRC 30th Anniversary of First Light

The National Synchrotron Radiation Research Center (NSRRC) commemorated the “30th Anniversary of First Light” on October 23rd. Premier Chien-Jen Chen of the Executive Yuan graced the occasion with his presence and delivered an address. He highlighted NSRRC’s steady and solid progress over the past three decades, from the “Taiwan Light Source (TLS)” to the “Taiwan Photon Source (TPS),” making it Taiwan’s largest R&D platform. Premier Chen envisions NSRRC as a key player in advancing Taiwan’s industry, academia, and research through its unique scientific and technological strengths. He underscored the imperative for NSRRC to sustain its R&D momentum, thus laying a solid foundation for Taiwan’s science and technology sector.

NSRRC hosts over 2,000 researchers annually from 20 countries, totaling 12,000 visits to utilize its exceptional synchrotron radiation capabilities for research purposes. The successful establishment of the TPS experiment facilities boosts utilization. Premier Chen emphasized the vital roles of both TLS and TPS in material development, cancer detection, biomedicine, pharmaceuticals, and achieving net-zero carbon emissions. NSRRC’s diverse contributions solidify its importance in Taiwan’s scientific and technological progress.

In addition to Premier Chen, notable guests included Deputy Minister of the National Science and Technology Council, Minn-Tsong Lin; former President of Academia Sinica, Yuan-Tsehn Lee; and esteemed Academicians Luo-Chuang Lee, Maw-Kuen Wu, Lih-Juann Chen, Chien-Te Chen, and Yu Wang. Also present were the Directors of the Taiwan Space Agency, the National Center for High-Performance Computing, and the Taiwan Instrument Research Center: Jong-Shinn Wu, Chau-Lyan Chang, and Cheng-Tang Pan, respectively. These attendees witnessed the inception, growth, and flourishing of Taiwan’s synchrotron radiation development.

Read more on the NSRRC website

Image: NSRRC 30th Anniversary address by Premier Chien-Jen Chen of the Executive Yuan

Credit: NSRRC

X-ray Excited Optical Luminescence (XEOL)

XEOL is an X-ray photon in/optical photon out technique that is related to the conversion of the X-ray energy absorbed by the materials to optical photons, involving multi-step energy transfer cascade processes. XEOL is often used together with XANES to reveal the electronic structure and optical properties of the system of interest, such as rare earth down conversion phosphors, quantum confined semiconductors, heterogeneous materials etc., and is applied in display/lighting technologies (TV, smartphone and LED lamps), scintillators, rechargeable batteries and energy conversion devices (photovoltaic cells). XEOL is now available at the end station of BM-08 XAFS/XRF beamline with emission spectra measurement capability under irradiation with X-ray beam.

Read more in SESAME website

Image: General view of the XEOL experimental setup at BM-08 XAFS/XRF beamline.  Sample environment with optical fiber for collecting the luminescence signals

Bleomycin: cancer drug with a hidden flaw

Scientists at the B23 beamline of the Diamond Light Source have used synchrotron light to make an important discovery about a common cancer therapy. Bleomycin is used to shrink a variety of tumours, but little is known about how this drug interacts with proteins in the bloodstream. The beamline scientists used synchrotron-grade circular dichroism to study how bleomycin interacts with two common blood proteins, one of which is normally elevated in people with cancer. Reporting in the International Journal of Molecular Sciences, they found that the drug bound more firmly to the protein elevated in cancer patients, suggesting there may be less of the free form available to elicit its therapeutic effect. On closer analysis, the team discovered that one of two variants of bleomycin binds more strongly to this protein than the other. They caution that the ratio of these two variants may need to be adjusted to improve the therapeutic benefit of this drug.

While screening compounds produced by bacteria in the 1960s, scientists made a serendipitous discovery. They stumbled upon a molecule called bleomycin with anticancer properties. Since then, this life-saving drug has been used to treat a variety of tumours from squamous cell carcinomas to lymphomas. The drug works by chopping up DNA in cancer cells, and this DNA-drug interaction has been characterised in the past. However, when bleomycin enters the bloodstream, it may interact with plasma proteins and less is known about how this impacts the drug’s effectiveness. Bleomycin shows promising outcomes when tested on cancer cells grown in the lab, but the serum extracts used in lab cultures have a different mix of proteins to the sera of cancer patients, so it’s worth exploring whether plasma proteins in patients could sequester the drug and reduce its effectiveness.

Beamline scientists at B23 were determined to explore this overlooked issue. Led by Rohanah Hussain, they harnessed ultraviolet light from synchrotron radiation to explore how the drug binds plasma proteins using a technique called circular dichroism.

Circular dichroism is the differential absorption of left- and right-circularly polarised ultraviolet light passing through a liquid solution containing biomolecules, in this case proteins with drugs The CD measurement is displayed as a curve (spectrum) of which shape reflects the architecture on  how the protein in solution is folded in helical, ribbon, turn and unordered segments.  Drug binding to protein can affect such a folding that is used to identify and quantify drug binding interaction, in this case bleomycin with the two major blood proteins. Another unique experiment carried out at B23 beamline is the use of the powerful synchrotron beamlight to irradiate multiple of times the protein-drug mixtures for photostability assessment, which varies depending upon the strength of the drug binding interactions.

Hussain explained:

The high photon flux available at the B23 beamline (Diamond Light Source) generated by synchrotron radiation is sufficient for disrupting the folding of biological macromolecules in a time scale of minutes to hours, providing a useful tool for accelerated photo-stability studies.

First, the team assessed whether Blenoxane®, a commercial preparation of bleomycin, could bind to two common plasma proteins: one was human serum albumin (HSA), an abundant serum protein that facilitates the delivery of drugs around the body through the bloodstream. The other was α1-acid glycoprotein (AGP), a protein produced by the liver in response to inflammation that is found in cancer patients at ten times the normal level.

To explore binding interactions with these two proteins, the team examined the circular dichroism curve for each protein across a spectrum of ultraviolet light, and then they observed whether addition of Blenoxane® altered the protein curve. Sizeable differences were observed with AGP, suggesting the drug binds and induced marked changes to the protein’s shape, but the curve didn’t shift for HSA. This doesn’t indicate that the drug doesn’t bind HSA, only that it doesn’t alter its shape upon interaction. The team adapted their circular dichroism experiments to confirm that Blenoxane® did bind to HSA by heating the sample to unfold (denature) the proteins’ architecture and then observing spectral changes with and without the drug present.

Read more on Diamond Light Source  website

Image: Rohanah Hussain is a Senior Beamline Scientist, working on the B23 beamline at Diamond

New AI-driven tool streamlines experiments

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have demonstrated a new approach to peer deeper into the complex behavior of materials. The team harnessed the power of machine learning to interpret coherent excitations, collective swinging of atomic spins within a system. 

This groundbreaking research, published recently in Nature Communications, could make experiments more efficient, providing real-time guidance to researchers during data collection, and is part of a DOE-funded project led by Howard University including researchers at SLAC and Northeastern University to use machine learning to accelerate research in materials. 

The team created this new data-driven tool using “neural implicit representations,” a machine learning development used in computer vision and across different scientific fields such as medical imaging, particle physics and cryo-electron microscopy. This tool can swiftly and accurately derive unknown parameters from experimental data, automating a procedure that, until now, required significant human intervention.

Peculiar behaviors

Collective excitations help scientists understand the rules of systems, such as magnetic materials, with many parts. When seen at the smallest scales, certain materials show peculiar behaviors, like tiny changes in the patterns of atomic spins. These properties are key for many new technologies, such as advanced spintronics devices that could change how we transfer and store data. 

To study collective excitations, scientists use techniques such as inelastic neutron or X-ray scattering. However, these methods are not only intricate, but also resource-intensive given, for example, the limited availability of neutron sources. 

Machine learning offers a way to address these challenges, although even then there are limitations. Past experiments used machine learning techniques to enhance the accuracy of X-ray and neutron scattering data interpretation. These efforts relied on traditional image-based data representations. But the team’s new approach, using neural implicit representations, takes a different route. 

Read more on SLAC website

A new approach to longer-lasting, faster-charging batteries

Researchers from McGill University and Université du Québec à Montreal (UQAM) have found a new approach to making inexpensive batteries that can not only hold large amounts of charge but also recharge quickly.

Their work focuses on improving lithium ion batteries, rechargeable cells that are used in electric vehicles, power tools, phones and more.

“The work that we’ve done at the CLS is going to open up the door to be able to make batteries that can be charged faster, which will be one of the ways that we can start implementing them in real use cases as soon as possible,” says McGill researcher Jeremy Dawkins, the lead author of a recent paper on the work published in the journal ChemElectroChem.

To understand how a battery performs, researchers need to see what’s going on inside while it is being used. This is challenging to do in most labs, but the Canadian Light Source (CLS) synchrotron at the University of Saskatchewan (USask) offers the bright, intense x-ray light required to peer into a working battery.

Lithium ion batteries can be made of a combination of different materials, which researchers tweak to get the performance they want.

Read more on CLS website

Promising material provides a simple, effective method capable of extracting uranium from seawater

  • Uranium can be extracted from seawater simply and effectively using a new material
  • Adding neodymium to layered double hydroxides (LDHs) improved their ability to capture uranium selectively
  • Multiple techniques at ANSTO clarified the octahedral coordination environment, oxidation state and adsorption mechanism

An Australian-led international research team, including a core group of ANSTO scientists, has found that doping a promising material provides a simple, effective method capable of extracting uranium from seawater.

The research, published in Energy Advances and featured on the cover, could help in designing new materials that are highly selective for uranium, efficient, and cost-effective.

Read more on the ANSTO website

Scientists uncover a rare component in Da Vinci’s Mona Lisa paint

Leonardo da Vinci (1452-1519) is considered one of the most important figures of the Renaissance. Whilst he wrote numerous manuscripts bearing on his many sources of interest such as engineering or architecture, he left very few clues on his painting materials. His taste for experimentation was strikingly present in his craft: The build-up of the different layers in each of his paintings is different, as are the materials used.

Now researchers from the laboratory Photophysique et photochimie supramoléculaires et macromoléculaires (CNRS/ENS Paris-Saclay), the Institut de recherche de chimie Paris (CNRS/Chimie ParisTech – PSL), the Centre de recherche et de restauration des musées de France (Ministère de la culture), the Louvre Museum, the Laboratoire d’archéologie moléculaire et structurale (CNRS/Sorbonne Université) and the ESRF, the European Synchrotron, have studied a microsample of the preparation layer of the Mona Lisa to shed light on Da Vinci’s painting methods. To get more clues about Da Vinci’s palette and technique, they also analysed several fragments from the Last Supper, another masterpiece by Leonardo.

The team used the techniques of synchrotron radiation high-angular resolution X-ray powder diffraction (SR-HR-XRPD), micro X-ray diffraction (µXRD) and micro Fourier-transform infrared spectroscopy (μ-FTIR) at the ESRF’s ID22, ID13 and ID21 beamlines, respectively. The results show the presence of a very uncommon composition in both the Mona Lisa’s ground layer and the Last Supper’s ground and paint layers.

“In Mona Lisa, we found a relatively high amount of plumbonacrite, an usual compound that we think is due to a specific mix of oil with lead oxide”, explains Victor Gonzalez, researcher at the laboratory Photophysique et photochimie supramoléculaires et macromoléculaires (CNRS/ENS Paris-Saclay) and corresponding author of the publication. However, the team had seen this component before, specifically in Rembrandt’s masterpiece The Night Watch, painted two centuries after the Mona Lisa. This enabled the scientists to identify possible hypothesis to explain its presence despite the chronological differences between the two artists.

“We faced the additional challenge that there are very few scientific analysis of Mona Lisa and of Da Vinci’s paintings in general, so it was difficult to compare our results with previous studies”, explains Marine Cotte, scientist at the ESRF and co- author of the publication.

Read more on ESRF website

Image: Artistic impression of the Mona Lisa. 

Credit: I. Fazlic, M. Cotte & V. Gonzalez.

Meet Xiaoqian Chen, NSLS-II Beamline Scientist

Xiao leads the quantum materials program at NSLS-II’s Coherent Hard X-Ray Scattering beamline

You’ve already spent a few years at Brookhaven, starting in 2016. What brought you back to the Laboratory?

My history with the Laboratory goes back to when I was a user at the original National Synchrotron Light Source (NSLS). I was in graduate school, and my group had our own beamline at NSLS, X1B. I was the person maintaining that beamline, so I came to know many people here.

When I became a postdoc, I decided to join the x-ray scattering group in Brookhaven’s Condensed Matter Physics & Materials Science Department because we shared the same research interests and coherent x-ray science was emerging. I joined when the Coherent Soft X-ray Scattering (CSX) beamline at NSLS-II had just achieved first light. I was able to participate in the first experiments there, and that was my postdoc work.

I then took a postdoc position at DOE’s Lawrence Berkeley National Laboratory and worked more on coherent x-ray science. After three years, I was offered a position at CHX to lead the quantum materials program.

What does your role at CHX entail? What kind of research do you do?

My research, in a broad sense, is in the field of condensed matter physics, looking at quantum materials. These are materials that have behaviors that are very heavily guided by quantum mechanical effects. For example, some have superconducting properties, and some have interesting magnetism. With help from my postdoc, I am looking into discovering new quantum effects in materials, and our work is supported by a Laboratory Directed Research and Development (LDRD) grant. Apart from my own research, I prepare an environment at CHX for scientists in our community to perform coherent x-ray experiments and study dynamical properties in their materials.

At CHX, we use coherent x-ray photons to track the dynamics inside materials. We can detect electron dynamics as fast as the nanosecond time scale with our recent detector installation. I’m currently trying to detect and study dynamics in materials that take place at that time scale. The ultimate goal is to find a signature of quantum entanglement. This property is a specific type of interaction between electrons; they show very different behavior from electrons in classical materials.

There are some other new capabilities that we are excited for users to experience. We have added a resonance scattering capability to look at element-specific information. For example, we can look at electrons in specific orbitals. We also added low temperature capability with a new cryostat that can chill samples to 4K. That’s very cold, and it will be very useful for studying quantum materials.

Read more on the NSLS-II website

Image: Xiaoqian Chen is a physicist and beamline scientist with the complex scattering program at the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory. At NSLS-II’s Coherent Hard X-ray Scattering (CHX) beamline, she studies materials with quantum behaviors and guides users in their investigations into quantum materials.

Transition metal insulators: The origin of colour

In a theoretical study, researchers have explained the vibrant colours of two compounds whose electronic properties seemingly prohibit such colouring. The hues exhibited by the two insulators originate from transitions in the spins of the electrons, which modify the way the materials absorb and reflect light in such a way as to create the bright colours. The theoretical framework employed by the team promises new insights in fields such as optoelectronics or in the study of qubits, the quantum bits used in quantum computers. 

Although colour is a familiar phenomenon, it is sometimes challenging to explain how the hues of certain materials come about. This is the case with insulators that contain transition metals. In these compounds, the energy gap between the valence band, in which the electrons are tightly bound to the atoms, and the conduction band, in which the electrons can move freely, is larger than the highest energy of photons of visible light—meaning that these materials should not absorb visible light. As the colour of a compound is complementary to the wavelengths it absorbs, we should thus perceive these insulators as being transparent instead of coloured. 

A team of researchers including the head of the European XFEL Theory group, Alexander Lichtenstein, now used two complementary theoretical methods to study the origin of colour in two typical transition metal insulators: nickel(II) oxide (NiO)—a green compound used in the production of ceramics and nickel steel as well as in thin-film solar cells, nickel–iron batteries, and fuel cells—and manganese(II) fluoride (MnF2), a pink material employed in the manufacture of special kinds of glass and lasers.

Read more on XFEL website

Image: Visualization of the orbital character of low-laying excitons in NiO, corresponding to a local ‘Frenkel’ exciton at an energy of 1.6 eV and a weakly bound, bright ‘Wannier-Mottâ’ exciton at an energy of 3.6 eV

Diamond materials as solar-powered electrodes

Spectroscopy shows what’s important!

It sounds like magic: photoelectrodes could convert the greenhouse gas CO₂ back into methanol or N2 molecules into valuable fertiliser – using only the energy of sunlight. An HZB study has now shown that diamond materials are in principle suitable for such photoelectrodes.

By combining X-ray spectroscopic techniques at BESSY II with other measurement methods, Tristan Petit’s team has succeeded for the first time in precisely tracking which processes are excited by light as well as the crucial role of the surface of the diamond materials.

At first glance, lab-grown diamond materials have little in common with their namesakes in the jewellery shop. They are often opaque, dark and look not spectacular at all. But even if their looks are unimpressive, they are promising in many different applications, for example in brain implants, quantum sensors and computers, as well as metal-free photoelectrode in photo-electrochemical energy conversion. They are fully sustainable and made of carbon only, they degrade little in time compared to metal-based photoelectrodes and they can be industrially produced!

Diamond materials are suitable as metal-free photoelectrodes because when excited by light, they can release electrons in water and trigger chemical reactions that are difficult to initiate otherwise. A concrete example is the reduction of CO2 to methanol which turns the greenhouse gas into a valuable fuel. It would also be exciting to use diamond materials to convert N2 into nitrogen fertiliser NH3, using much less energy than the Haber-Bosch process.

However, diamond electrodes oxidize in water and oxidized surfaces, it was assumed, no longer emit electrons into the water. In addition, the bandgap of diamond is in the UV range (at 5.5 eV), so visible light is unlikely to be sufficient to excite electrons. In spite of this expectation, previous studies have shown puzzling emission of electrons from visible light excitation. A new study by Dr. Tristan Petit’s group at HZB now brings new insights and gives cause for hope.

Dr Arsène Chemin, a postdoctoral researcher in Petit’s team, studied samples of diamond materials produced at the Fraunhofer Institute for Applied Solid State Physics in Freiburg. The samples were engineered to facilitate the CO2 reduction reaction: doped with boron to insure good electrical conductivity and nanostructured, which gives them huge surfaces to increase the emission of charge carriers such as electrons.

Chemin used four X-ray spectroscopic methods at BESSY II to characterize the surface of the sample and the energy needed to excite specific electronic surface states. Then, he used the surface photovoltage measured in a specialised laboratory at HZB to determine which ones of these states are excited and how the charge carriers are displaced in the samples. In complement, he measured the photoemission of electrons of samples either in air or in liquid. By combining these results, he was able for the first time to draw a comprehensive picture of the processes that take place on the surfaces of the sample after excitation by light.

Read more on HZB website

Image: Four diamond materials are shown here: “Diamond black” made of polycrystalline nanostructured carbon (top right), the same material before nanostructuring (top left), an intrinsic single crystal (bottom left) and a single crystal doped with boron (bottom right).

Credit: A. Chemin/HZB

ALS at 30: Share your memories

October 5, 2023, marks 30 years since first light at the ALS. The number of beamlines grew to 40, as many as 2,000 users have come to the facility each year, and over 16,000 publications have resulted from work here. This is your chance to fill in the details beyond those numbers.

Submit your memories here

Image: The ALS with the Bay Area in the background

Credit: ALS

Breakthrough towards cheap and efficient solar cells

Scientists from EPFL and CSEM have made remarkable progress in the photovoltaics field, specifically in perovskite-on-silicon tandem solar cells, by achieving an impressive efficiency of 31.25%. This noteworthy accomplishment is a result of advancements in materials and processes that have successfully unlocked the true potential of this emerging technology. Studies at NCD-SWEET beamline of ALBA have been carried out to analyse these materials. The scientific breakthrough behind this milestone has been published in Science, representing a significant step towards a greener, cleaner energy future and the ongoing energy transition.

Cerdanyola del Vallès, 4th October 2023 Silicon solar cells that are commonly used for solar electricity generation are limited in terms of efficiency — the amount of sunlight that hits a solar cell and gets converted into electricity. The current highest efficiency records for silicon-only solar cells stand around 24.5% for commercial cells and 27% in laboratory settings. These figures are considered close to the theoretical maximum of 29% for such cells, with little progress in moving this number higher in recent years. Research groups worldwide are engaged in efforts to enhance the efficiency and develop innovative materials, like metal halide perovskites, as potential alternatives to silicon.

Racing past crucial energy barrier

To overcome this efficiency limitation and further reduce the costs of solar electricity, scientists from EPFL’s PV-Lab and CSEM have been exploring innovative approaches and finally demonstrated, in the article published in Science,an efficiency of 31.25% by stacking silicon and perovskite cells in a so-called tandem structure. This achievement marks the first time a low-cost technology has surpassed the 30% efficiency milestone.

Tandem solar cells offer improved utilization of solar energy by optimizing each sub-cell to capture different parts of the solar spectrum. However, typical limitation of perovskite-on-silicon tandem cells is the recombination losses that occur at the perovskite interface with the electron selective contact. Recombination refers to the loss of photogenerated charge carriers before they can be collected and utilized to generate electricity.

To address this issue, EPFL’s and CSEM’s scientists started with a standard commercial silicon cell and incorporated an additive in the processing sequence when growing the perovskite crystal on top. This additive effectively regulated the perovskite crystallization process and passivated the perovskite top interface. Passivation involves adapting the structure and chemistry of interfaces and surfaces so that energy loss is minimized, and a maximum of the energy generated can be utilized efficiently.

A bright light for a brighter energy future

In order to deeply analyse the impact of the additive on the perovskite crystallization process, grazing incidence wide-angle x-ray scattering (GIWAXS) was performed at the ALBA Synchrotron. “GIWAXS provides detailed information about the crystallographic structure, orientation, and phase transitions within the material”, explains Eduardo Solano, beamline scientist at ALBA. In particular, Solano gives support to research groups who come to ALBA for using this synchrotron light-based technique at NCD-SWEETa flexible dynamic multipurpose beamline that can accommodate a large variety of sample environments for in situ experiments.

Read more on ALBA website

Image: From left to right, Julian Steele, scientist at KU Leuven and at the University of Queensland, and Eduardo Solano, beamline scientist at NCD-SWEET.