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Researchers at EPFL have created the first detailed model explaining the quantum-mechanical effects that cause photoluminescence in thin gold films, a breakthrough that could advance the development of solar fuels and batteries.

Luminescence, the process where substances emit photons when exposed to light, has long been observed in semiconductor materials like silicon. This phenomenon involves electrons at the nanoscale absorbing light and subsequently re-emitting it. Such behavior provides researchers with valuable insights into the properties of semiconductors, making them useful tools for probing electronic processes, such as those in solar cells.

In 1969, scientists discovered that all metals luminesce to some degree, but the intervening years failed to yield a clear understanding of how this occurs. Renewed interest in this light emission, driven by nanoscale temperature mapping and photochemistry applications, has reignited the debate surrounding its origins. But the answer was still unclear – until now.

It is a common hack to stretch a balloon out to make it easier to inflate. When the balloon stretches, the width crosswise shrinks to the size of a string. Noah Stocek, a PhD student collaborating with Western University physicist Giovanni Fanchini, has developed a new nanomaterial that demonstrates the opposite of this phenomenon.

Working at Interface Science Western, home of the Tandetron Accelerator Facility, Stocek, and Fanchini formulated two-dimensional nanosheets of tungsten semi-carbide (or W2C, a chemical compound containing equal parts of tungsten and carbon atoms) which when stretched in one direction, expand perpendicular to the applied force. This structural design is known as auxetics.

Dielectric capacitors are ubiquitous components that play a vital role in electronic devices and energy storage systems. Their ability to rapidly discharge significant amounts of energy makes them indispensable for high-power applications.

“High-energy and high-power capacitors are the backbone of reliable power supplies, especially as we transition towards renewable energy sources,” explains Alamgir Karim, Dow Chair and Welch Foundation Professor of Chemical Engineering at UH and a faculty mentor on the project. “However, current dielectric capacitors fall short in terms of energy storage capacity compared to other options like batteries. The advantage of capacitors lies in their superior power density, making them a more suitable choice for various applications.”

The key factor influencing a capacitor’s energy storage is a combination of its permittivity (ε) and dielectric breakdown strength (EBD). Professor Karim emphasizes, “To enhance a capacitor’s energy storage, advancements in both these aspects are crucial.”

Engineers at Georgia Tech have designed a process that converts carbon dioxide removed from the air into useful raw material that could be used for new plastics, chemicals, or fuels.

Their approach dramatically reduces the cost and energy required for these direct air capture (DAC) systems, helping improve the economics of a process the researchers said will be critical to addressing climate change.

The key is a new kind of catalyst and electrochemical reactor design that can be easily integrated into existing DAC systems to produce useful carbon monoxide (CO) gas. It’s one of the most efficient such design ever described in scientific literature, according to lead researcher Marta Hatzell and her team. They have published the details in Energy & Environmental Science.

Scientists at the Leibniz Institute of Plant Biochemistry (IPB) have succeeded for the first time in stably and precisely inserting large gene segments into the DNA of higher plants very efficiently. To do this, they optimized the gene-editing method CRISPR/Cas, commonly known as “genetic scissors.”

The improved CRISPR method offers great opportunities for the targeted modification of genes in higher plants, both for breeding and research. The study, led by Prof. Alain Tissier and Dr. Tom Schreiber, has been published in Molecular Plant.

CRISPR/Cas is a method with enormous potential for the targeted modification of individual genes. However, this does not apply to all kinds of genetic modifications that breeders and scientists have on their wish lists. While the genetic scissors are ideal for knocking out genes, i.e., switching off or removing existing genes, they do not work well for precisely inserting genes or replacing gene segments. To date, genetic scissors have been too inefficient and therefore of little use for the targeted insertion of genes into the DNA of higher plants.

Single-cell multiplexing techniques (cell hashing and genetic multiplexing) combine multiple samples, optimizing sample processing and reducing costs. Cell hashing conjugates antibody-tags or chemical-oligonucleotides to cell membranes, while genetic multiplexing allows to mix genetically diverse samples and relies on aggregation of RNA reads at known genomic coordinates. We develop hadge (hashing deconvolution combined with genotype information), a Nextflow pipeline that combines 12 methods to perform both hashing-and genotype-based deconvolution. We propose a joint deconvolution strategy combining best-performing methods and demonstrate how this approach leads to the recovery of previously discarded cells in a nuclei hashing of fresh-frozen brain tissue.

This article is part of a series of pieces on advances in sustainable battery technologies that Physics Magazine is publishing to celebrate Earth Week 2024. See also: Q&A: Electrochemists Wanted for Vocational Degrees; Research News: Lithium-Ion “Traffic Jam” Behind Reduced Battery Performance; Q&A: The Path to Making Batteries Green; News Feature: Sodium Batteries as a Greener Lithium Substitute.

Since the first prototype made its debut in 2000, rechargeable magnesium batteries have continued to be both technologically attractive and commercially out of reach. The attraction arises from magnesium’s advantages over lithium: it is 1,000 times more abundant in Earth’s crust and is chemically less hazardous. The unrealized commercialization is largely down to the difficulty in identifying a material to serve as an effective and robust cathode. Tomoya Kawaguchi of Tohoku University in Japan and his collaborators may now have solved that problem through their demonstration of a material that satisfies one of the most important requirements of a good cathode: it can reversibly accept and release ions over repeated charging cycles [1].

The discharge of an electrochemical battery releases electrons that flow through the connected circuit. It also releases ions from the battery’s anode that flow through the battery’s electrolyte, in the opposite direction to the electrons, and then lodge in the cathode. The flows reverse directions during recharging. In a lithium-ion battery, the cathode is made from a lithium oxide and takes the form of either a layered material or a crystalline solid known as a spinel.

Medically, AI is helping us with everything from identifying abnormal heart rhythms before they happen to spotting skin cancer. But do we really need it to get involved with our genome? Protein-design company Profluent believes we do.

Founded in 2022 in Berkeley, California, Profluent has been exploring ways to use AI to study and generate new proteins that aren’t found in nature. This week, the team trumpeted a major success with the release of an AI-derived protein termed OpenCRISPR-1.

The protein is meant to work in the CRISPR gene-editing system, a process in which a protein cuts open a piece of DNA and repairs or replaces a gene. CRISPR has been actively in use for about 15 years, with its creators bagging the Nobel prize in chemistry in 2020. It has shown promise as a biomedical tool that can do everything from restoring vision to combating rare diseases; as an agricultural tool that can improve the vitamin D content of tomatoes, and slash the flowering time of trees from decades to months; and much more.

Light-driven molecular motors were first developed nearly 25 years ago at the University of Groningen, the Netherlands. This resulted in a shared Nobel Prize for Chemistry for Professor Ben Feringa in 2016. However, making these motors do actual work proved to be a challenge. A new paper from the Feringa lab, published in Nature Chemistry on 26 April, describes a combination of improvements that brings real-life applications closer.

First author Jinyu Sheng, now a postdoctoral researcher at the Institute of Science and Technology Austria (ISTA), adapted a “first generation” light-driven molecular motor during his Ph.D. studies in the Feringa laboratory. His main focus was to increase the efficiency of the motor molecule. “It is very fast, but only 2% of the photons that the molecule absorbs drive the rotary movement.”

This poor efficiency can get in the way of real-life applications. “Besides, increased efficiency would give us better control of the motion,” adds Sheng. The rotary motion of Feringa’s molecular motor takes place in four steps: two of them are photochemical, while two are temperature-driven. The latter are unidirectional, but the photochemical steps cause an isomerization of the molecule that is usually reversible.