Researchers from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) and the University of New South Wales have achieved a new world-record efficiency for two-junction solar cells, creating a cell with two light-absorbing layers that converts 32.9% of sunlight into electricity. Key to the cell's design is a series of more than 150 ultrathin layers of alternating semiconductors that create quantum wells in the cell's bottom absorber, allowing it to capture energy from a key range of the solar spectrum.
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One way to harness solar energy is by using solar electricity to split water molecules into oxygen and hydrogen. The hydrogen produced by the process is stored as fuel, in a form that can be used to generate power upon demand. To split water molecules into their component parts, a catalyst is necessary, but the catalytic materials currently used in the process are not efficient enough to make the process practical. Using an innovative chemical strategy developed at the University of Virginia, a team of researchers has produced a new form of catalyst using the elements cobalt and titanium. The new process involves creating active catalytic sites at the atomic level on the surface of titanium oxide nanocrystals, which results in a durable catalytic material.
A team of physicists at the University of Maryland, Baltimore County (UMBC) has provided reliable information about which new materials might have desirable properties for a range of applications and could exist in a stable form in nature. The team used cutting-edge computer modeling techniques to predict the properties of 2D materials that have not yet been made in real life.
Physicists at Princeton University have used a material known as magic-angle twisted bilayer graphene to explore how interacting electrons can give rise to rise to surprising phases of matter. By layering two sheets of graphene on top of each other, with the top layer angled at precisely 1.1 degrees, the Princeton researchers produced topological quantum states of matter, which are intriguing classes of quantum phenomena. Topological quantum states first came to the public's attention in 2016 when three scientists – Princeton's Duncan Haldane, who is Princeton's Thomas D. Jones Professor of Mathematical Physics and Sherman Fairchild University Professor of Physics, together with David Thouless and Michael Kosterlitz – were awarded the Nobel Prize for their work in uncovering the role of topology in electronic materials.
Scientists at Rice University have found that nature’s ubiquitous weak force (Van der Waals) is sufficient to indent rigid nanosheets, extending their potential for use in nanoscale optics or catalytic systems. Without applying any other force, the scientists saw that the silver nanosheets acquired permanent bumps where none existed before.
Researchers at North Carolina State University have developed a new technology, called Artificial Chemist 2.0, that allows users to go from requesting a custom quantum dot to completing the relevant R&D and beginning manufacturing in less than an hour. The technology is completely autonomous and uses artificial intelligence and automated robotic systems to perform multi-step chemical synthesis and analysis.
In a step toward making more accurate and uniform 3-D-printed parts, researchers at the National Institute of Standards and Technology (NIST) have demonstrated a method of measuring the rate at which microscopic regions of a liquid raw material harden into a solid plastic when exposed to light. NIST's custom atomic force microscope, with a nanometer-scale, cylinder-shaped tip, revealed that the complex process of curing resins, as they react under light to form polymers, requires controlling how much of the light's energy goes into forming the polymer and how much the polymer spreads out, or diffuses, during 3-D printing.
Researchers at the University at Buffalo have discovered a new, two-dimensional transistor that is made of graphene and the compound molybdenum disulfide and could help usher in a new era of computing. The transistor requires half the voltage of current semiconductors and has a current density greater than similar transistors under development.
Scientists at Columbia University and the University of Glasgow have discovered a new chemical design principle for exploiting destructive quantum interference. The scientists used their approach to create a six-nanometer single-molecule switch in which the on-state current is more than 10,000 times greater than the off-state current. They demonstrated that this approach can be used to produce stable and reproducible single-molecule switches at room temperature that can carry currents exceeding 0.1 microamp in the on state.
An international team of researchers, led by scientists at Penn State, found that arranging micro-supercapacitor cells in a serpentine, island-bridge layout allows the configuration to stretch and bend at the bridges, while reducing deformation of the micro-supercapacitors. The researchers used non-layered, ultrathin zinc-phosphorus nanosheets and 3D laser-induced graphene foam – a highly porous, self-heating nanomaterial – to construct the island-bridge design of the cells and noticed that these micro-supercapacitor arrays can charge and discharge efficiently and store the energy needed to power a wearable device.