#dopants
Fine-tuning chemistry by doping with transition metals produced stability in bismuth oxide
ANSTO has contributed to research led by the University of Sydney, involving doping transition metals in a polymorph of bismuth oxide in a search for more structural stability.
Cubic high-temperature polymorph of bismuth oxide, δ-Bi2O3, is the best known oxide ionic conductor but its narrow stability range (729—817 °C), which is close to its melting temperature of 817 °C precludes its practical use.
A large collaboration, led by Professor Chris Ling and Dr. Julia Wind (as part of her Ph.D.) from the University of Sydney involving researchers from ANSTO and two other universities, has achieved the design and understanding of the complex crystal structure and chemistry behind a commensurate structure within the fast-ion conducting stabilised bismuth oxide, co-doped with chromium and niobium, Bi23CrNb3O45.
The study was published in the Chemistry of Materials.
Post link
Chameleon-Like Material Spiked With Boron Helps Bring Brain-Like Computing to Silicon Chips
Chameleon-Like Material Spiked With Boron Comes Closer To Mimicking Brain Cells
In a new study, Texas A&M researchers in the Department of Materials Science and Engineering describe a new material that comes close to mimicking how brain cells perform computations.
Each waking moment, our brain processes a massive amount of data to make sense of the outside world. By imitating the way the human brain solves everyday problems, neuromorphic systems have tremendous potential to revolutionize big data analysis and pattern recognition problems that are a struggle for current digital technologies.
But for artificial systems to be more brain-like, they need to replicate how nerve cells communicate at their terminals, called the synapses.
Post link
The next generation of power electronics? Gallium nitride doped with beryllium: How to cut down energy loss in power electronics? The right kind of doping
The trick is to be able to use beryllium atoms in gallium nitride. Gallium nitride is a compound widely used in semiconductors in consumer electronics from LED lights to game consoles. To be useful in devices that need to process considerably more energy than in your everyday home entertainment, though, gallium nitride needs to be manipulated in new ways on the atomic level.
[…]
“There is growing demand for semiconducting gallium nitride in the power electronics industry. To make electronic devices that can process the amounts of power required in, say, electric cars, we need structures based on large-area semi-insulating semiconductors with properties that allow minimising power loss and can dissipate heat efficiently. To achieve this, adding beryllium into gallium nitride - or ‘doping’ it - shows great promise,” explains Professor Filip Tuomisto from Aalto University.
Post link
Three dimensional Mn-doped nanosheets as efficient electrocatalysts for alkaline water splitting
Hydrogen has attracted extensive attention from academia and industry as an energy source due to its intrinsic environmental compatibility, abundance, and high energy density (120 MJ kg−1). Electrocatalytic water splitting is an environmentally friendly route to produce hydrogen, especially when the electricity is from renewable sources that minimize carbon dioxide emissions throughout the process.
Theoxygen evolution reaction (OER) on the anode and hydrogen evolution reaction (HER) on the cathode are two half-reactions in electrocatalytic water splitting. Pt- and Ru/Ir-based compounds are the best-known high-performance noble metal electrocatalysts for HER and OER, respectively. However, the scarcity and high cost of such noble metals hamper their application in water electrolysis. Therefore, with global prospects, it is essential to develop earth-abundant non-noble metal electrocatalysts for next-generation water splitting technologies. Recently, Ni-based electrocatalysts have been confirmed to be effective for boosting electrocatalytic water splitting, but their performances are not high enough for large-scale hydrogen production.
A team in China has successfully fabricated Mn-doped Ni2O3/Ni2P and Mn-doped NixSy/Ni2P through facile hydrothermal reaction and subsequently phosphorization and sulfurization method.
Post link
Researchers report new understanding of thermoelectric materials
The promise of thermoelectric materials as a source of clean energy has driven the search for materials that can efficiently produce substantial amounts of power from waste heat.
Researchers reported a major step forward Friday, publishing in Science Advances the discovery of a new explanation for asymmetrical thermoelectric performance, the phenomenon that occurs when a material that is highly efficient in a form which carries a positive charge is far less efficient in the form which carries a negative charge, or vice versa.
Zhifeng Ren, M. D. Anderson Chair Professor of Physics at the University of Houston, director of the Texas Center for Superconductivity at UH and corresponding author on the paper, said they have developed a model to explain the previously unaddressed disparity in performance between the two types of formulations. They then applied the model to predict promising new materials to generate power using waste heat from power plants and other sources.
Post link
Researchers make first observation of atoms moving inside bulk material
Researchers at the Department of Energy’s Oak Ridge National Laboratory have obtained the first direct observations of atomic diffusion inside a bulk material. The research, which could be used to give unprecedented insight into the lifespan and properties of new materials, is published in the journal Physical Review Letters.
“This is the first time that anyone has directly imaged single dopant atoms moving around inside a material,” said Rohan Mishra of Vanderbilt University who is also a visiting scientist in ORNL’s Materials Science and Technology Division.
Semiconductors, which form the basis of modern electronics, are “doped” by adding a small number of impure atoms to tune their properties for specific applications. The study of the dopant atoms and how they move or “diffuse” inside a host lattice is a fundamental issue in materials research.
Traditionally, diffusion of atoms has been studied through indirect macroscopic methods or through theoretical calculations. Diffusion of single atoms has previously been directly observed only on the surface of materials.
Post link
What Happens Between the Sheets? Extremely-Promising Superconductor Surprises Everyone
‘Floating’ Graphene on a Bed of Calcium Atoms
Adding calcium to graphene creates an extremely-promising superconductor, but where does the calcium go?
Adding calcium to a composite graphene-substrate structure creates a high transition-temperature (Tc) superconductor.
In a new study, an Australian-led team has for the first time confirmed what actually happens to those calcium atoms: surprising everyone, the calcium goes underneath both the upper graphene sheet and a lower ‘buffer’ sheet, ‘floating’ the graphene on a bed of calcium atoms.
Superconducting calcium-injected graphene holds great promise for energy-efficient electronics and transparent electronics.
Post link
