Energy

For more than 100 years, scientists have used a method called crystallography to determine the atomic structure of materials, but this technique only works well when researchers have large, pure crystals. For a powder of nanocrystals, the method only hints at the unseen structure. Now, scientists at Columbia Engineering have created a machine learning algorithm that can observe the pattern produced by a powder of nanocrystals to infer their atomic structures.

Scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) and SLAC National Accelerator Laboratory have revealed the fundamental mechanisms that limit the performance of copper nanocatalysts – critical components in chemical reactions that transform carbon dioxide and water into valuable fuels and chemicals. Copper’s catalytic properties quickly degrade during these reactions, diminishing its performance over time.

Researchers at Cornell University have, for the first time, identified what happens when bacteria receive electrons from quantum dots. Using fluorescence lifetime imaging microscopy with two-photon excitation on a quantum dot and bacteria, the researchers identified a distinct halo surrounding the bacteria, which suggested the charge transfer was receiving some peripheral assistance. It turned out that an electron could either move directly from the quantum dot to the bacterium or be transferred from the bacterium via shuttle molecules.

Researchers from the University of Connecticut; Harvard University; the Massachusetts Institute of Technology; RTX BBN Technologies in Arlington, VA; and the National Institute for Materials Science in Tsukuba, Japan, have discovered that electrons in twisted trilayer graphene behave unlike those described by Bardeen-Cooper-Schrieffer theory of paired electrons. However,  twisted trilayer graphene shares properties with high-temperature cuprates, in which electrons also pair up, but differently from traditional superconductors.

Scientists from the University of Oklahoma and Northwestern University have shown that adding a crystalized molecular layer to quantum dots made of perovskite prevents them from darkening or blinking. Quantum dots, which are nanoparticles that have unique optical and electronic properties, usually fade out after 10–20 minutes of use. The crystal coverings developed in this study extend the continuous light emission of quantum dots to more than 12 hours with virtually no blinking.

Researchers from Oregon State University, The Ohio State University, and the Southern University of Science and Technology in Shenzhen, China, have helped characterize a novel electrocatalyst developed by collaborators at Yale University and helped explain its improved efficiency for deriving methanol from carbon dioxide. The researchers’ dual-site catalyst is the result of combining two different catalytic sites at adjacent locations, separated by about 2 nanometers, on carbon nanotubes.

Researchers from Rice University, the University of California Berkeley, the University of Pennsylvania, and the Massachusetts Institute of Technology have shed light on how the extreme miniaturization of thin films affects the behavior of relaxor ferroelectrics — materials with noteworthy energy-conversion properties used in sensors, actuators, and nanoelectronics. The findings reveal that as the films shrink to dimensions comparable to internal polarization structures within the films, their fundamental properties can shift in unexpected ways.

Researchers from the U.S. Department of Energy’s Argonne National Laboratory and the University of Cambridge have unveiled the existence of an intriguing link between ferroelectric domain walls and electron interactions in a type of van der Waals 2D material. A domain wall is a boundary or interface separating regions inside a material that exhibit different orientations of ferroelectric polarization. The link discovered by the researchers gives rise to a new type of superconductivity that is unique to these 2D materials.

Researchers from the U.S. Department of Energy's SLAC National Accelerator Laboratory, Stanford University, and the University of California, Davis, have developed a new software tool that can provide more quantitative details about the structure of the active sites in single atom catalysts in much less time, compared to current methods. Normally, a catalyst uses an inert support to stabilize nanometer-sized clusters of metal atoms, or metal nanoparticles.

University of Missouri scientists are unlocking the secrets of halide perovskites – a material that might bring us closer to energy-efficient optoelectronics. The scientists are studying the material at the nanoscale. At this level, the material is astonishingly efficient at converting sunlight into energy. To optimize the material for electronic applications, the scientists used a method called ice lithography, known for its ability to fabricate materials at the nanometer scale.