Science Alert November 5, 2021 Lead halide perovskite (LHP) semiconductors show exceptional optoelectronic properties. Barriers for their applications, however, lie in their polymorphism, instability to polar solvents, phase segregation, and susceptibility to the leaching of lead ions. An international team of researchers (Australia, Slovenia, China, UK, France, Japan, Singapore) has developed a process to wrap or bind the nanocrystals in porous glass to stabilize the material, enhance its efficiency, and inhibit the toxic lead ions from leaching out from the materials. The product showed high stability when exposed to heat, light, air, and humidity, and was able to retain 80 […]
Category Archives: Advanced materials
Unmasking the magic of superconductivity in twisted graphene
Science Daily October 20, 2021 An international team of researchers (USA – Princeton University, Japan) combined tunnelling and Andreev reflection spectroscopy with the scanning tunnelling microscope to observe several key experimental signatures for unconventional superconductivity in magic angle twisted bilayer graphene (MATBG). They showed that the tunnelling spectra below the transition temperature Tc are inconsistent with those of a conventional s-wave superconductor, but rather resemble those of a nodal superconductor with an anisotropic pairing mechanism. They observed a large discrepancy between the tunnelling gap which far exceeds the mean-field BCS ratio, and the gap extracted from Andreev reflection spectroscopy. The […]
Liquid metal proven to be cheap and efficient CO2 converter
Phys.org October 13, 2021 An international team of researchers (Australia, USA – UCLA, North Carolina State University) has developed technology to capture carbon that uses suspensions of gallium liquid metal to reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver-gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio was […]
‘Back to basics’ approach helps unravel new phase of matter
Science Daily September 27, 2021 It was thought that the properties of prethermal discrete time crystals (DTCs) were reliant on quantum physics. An international team of researchers (UK, Germany) found that a simpler approach, based on classical physics can be used to understand these mysterious phenomena. Using a computer simulation they studied many interacting spins under the action of a periodic magnetic field using classical Hamiltonian dynamics. The resulting dynamics showed in a neat and clear way the properties of prethermal DTCs: for a long time, the magnetization of the system oscillates with a period larger than that of the […]
Scientists create material that can both move and block heat
Science Daily September 30, 2021 An international team of researchers (USA – University of Chicago, University of Illinois, Cornell University, Sweden) stacked ultra-thin layers of crystalline sheets on top of each other, but rotated each layer slightly, creating a material with atoms that are aligned in one direction but not in the other. They measured the results and found that a microscopic wall made of this material was extremely good at preventing heat from moving between compartments. They could transport heat along the wall very easily. Making computer chips smaller creates a high-power density environment. But if we can use […]
Twisted layers of MoS2 enable the engineering of novel states of matter
Nanowerk September 24, 2021 An international team of researchers (Germany, USA – Simons Foundation, University of Pennsylvania, Spain) has discovered that two twisted layers of MoS2 can be used to control kinetic energy scales in solids. In addition to using the twist angle to control the material’s electronic properties, they demonstrated that the electrons in MoS2 can interfere destructively, stopping their motion for certain paths making it possible to engineer exotic magnetic states. They studied the collective behavior of twisted bilayer MoS2 in the presence of interactions and characterized an array of different magnetic and orbitally-ordered correlated phases, which may […]
Unbreakable glass inspired by seashells
Phys.org September 28, 2021 Nacre, mother of pearl, made of stiff pieces of chalk-like matter that are layered with highly elastic soft proteins, has the rigidity of a stiff material and durability of a soft material. It is 3000 times tougher than the materials that compose it. An international team of researchers (Canada, USA- University of Colorado) took the architecture of nacre and replicated it with layers of glass flakes and acrylic, yielding an exceptionally strong yet opaque material that can be produced easily and inexpensively. They made the composite optically transparent. By tuning the refractive index of the acrylic, […]
Creating cotton that is fireproof and comfortable
Phys.org September 15, 2021 Researchers in Switzerland utilized a tri-functional phosphorous compound (trivinylphosphine oxide), which has the capability of reacting only with specifically added molecules (nitrogen compounds like piperazin) to form its own network inside cotton. This makes the cotton permanently fire-resistant without blocking the favorable -OH groups. This flame retardant treatment does not include carcinogenic formaldehyde. The phosphine oxide networks do not wash out. After 50 launderings, 95 percent of the flame retardant network was still present in the fabric. To fix the phosphine oxide networks inside the cellulose they treated the cotton with an aqueous solution of phosphorus […]
Researchers create nanoparticle paste to make perovskite solar cells more efficient
Nanowerk September 10, 2021 Large-scale and low-cost approaches for creating functional nanostructures are still not developed. An international team of researchers (Russia, Italy) has developed a method to create mesoporous electron transport layer based on optically resonant silicon nanoparticles incorporated into TiO paste to be applied for perovskite (MAPbI) solar cell. The inclusion of Mie-resonant silicon nanoparticles helps to improve light absorption by a perovskite layer without reduction of the active material. The management of Si nanoantennas concentration provides a power conversion efficiency higher than 21% by increasing all main device parameters. The new silicon nanoparticles provide physical understanding on […]
GaN-on-diamond semiconductor material that can take the heat – 1000 C to be exact
Nanowerk September 9, 2021 Researchers in Japan used the surface activated bonding (SAB) method to successfully bond GaN and diamond and demonstrated that the bonding is stable even when heated to 1,000°C. A 5.3 nm-thick intermediate layer composed of amorphous carbon and diamond is formed at the as-bonded heterointerface. As the team increased annealing temperatures, the layer thickness decreased suggesting the intermediate layer can be completely removed by optimizing the annealing process. As no peeling was observed at the heterointerface after annealing at 1000°C these results indicate that the GaN/diamond heterointerface can withstand harsh fabrications processes. The material shows promise […]