Science Daily September 21, 2023 Quasi-1D nanoribbons provide a unique route to diversifying the properties of their parent 2D nanomaterial, introducing lateral quantum confinement and an abundance of edge sites. Phosphorus-only materials do not conduct electricity very well, hindering their use for certain applications. Researchers in the UK created a new family of nanomaterials with the creation of arsenic–phosphorus alloy nanoribbons (AsPNRs). By ionically etching the layered crystal black arsenic–phosphorus using lithium electride followed by dissolution in amidic solvents, solutions of AsPNRs were formed. The ribbons were typically few-layered, several micrometers long with widths tens of nanometers across, and both […]
Tag Archives: Materials science
Transparent wood-based coating doesn’t fog up
Nanowerk September 26, 2023 Researchers in Finland developed a way to turn a waste material from wood into a bio-based transparent film that can be used for anti-fogging or anti-reflective coatings on glasses or vehicle windows. They prepared optically clear lignin nanoparticle dispersions from acetylated lignin. Thin lignin nanoparticle films remained transparent when deposited on glass and other smooth surfaces, and monolayered particle films provided effective antifogging properties. The particles could also be used to prepare multilayered films with bright structural colors that could be controlled via the film-thickness and were retained in dry conditions. They also developed an improved […]
Scientists develop self-healing elastomer for flexible electronics
Phys.org September 18, 2023 The mechanical properties of the substrate elastomers are often poor due to the inherent performance of the materials. Researchers in China prepared a poly(vinyl alcohol) (PVA)-based self-healing material with high strength and good thermal stability by side-linked grafting modification of PVA with a one-step esterification reaction. Benefiting from the hydrogen bonds and ion coordination between iron ions and carboxyl groups, the synthesized elastomer exhibited excellent mechanical properties and good self-healing performance. The high sensitivity and self-healing performance of a silver nanowire-coated elastomer strain sensor demonstrated the wide potential applicability of the prepared PVA-based elastomers in health […]
A new design strategy for mechanoresponsive materials with high thermal tolerance
Phys.org September 11, 2023 Radical type mechanophores (RMs), molecules that can undergo small-scale chemical reactions upon exposure to a mechanical stimulus are studied due to their potential application in the fabrication of highly functionalized polymers. However, the lack of a rational design concept with pre-determined properties limits their development. Researchers in Japan have developed a rational design strategy of RMs with high thermal tolerance while maintaining mechanoresponsiveness. Through experimental and theoretical analysis, they found that the high thermal tolerance of RMs is related to the radical-stabilization energy (RSE) as well as the Hammett and modified Swain–Lupton constants at the para-position. […]
Pixel-by-pixel analysis yields insights into lithium-ion batteries
MIT News September 13, 2023 Reaction rates at spatially heterogeneous, unstable interfaces are difficult to quantify, yet they are essential in engineering many chemical systems, such as batteries and electrocatalysts. Experimental characterizations of such materials by operando microscopy produce rich image datasets, but data-driven methods to learn physics from these images are lacking because of the complex coupling of reaction kinetics, surface chemistry and phase separation. A team of researchers in the US (MIT, Stanford University, industry, SLAC National Accelerator Laboratory) showed that heterogeneous reaction kinetics can be learned from in situ scanning transmission X-ray microscopy (STXM) images of carbon-coated […]
Scientists unlock reversible twisting of nanoscale materials
Nanowerk September 13, 2023 Nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) and retwisting areas more difficult to achieve. Researchers in China have reported a new reciprocal effect between molecular geometry and crystal structure which triggered a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stemmed from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices gave rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual […]
Valleytronics: Innovative way to store and process information up to room temperature
Science Daily September 8, 2023 The two degenerate valleys in transition metal dichalcogenides can be used to store and process information for quantum information science and technology. A major challenge is maintaining valley polarization at room temperature where phonon-induced intervalley scattering is prominent. A team of researchers in the US (Brookhaven National Laboratory, industry) has demonstrated room temperature valley polarization in heterostructures of monolayer MoS2 and naphthylethylammine based one-dimensional chiral lead halide perovskite. By optically exciting the heterostructures with linearly polarized light close to resonance and measuring the helicity resolved photoluminescence, they obtained a degree of polarization of up to […]
Scientists design novel nonlinear circuit to harvest clean power using graphene
Phys.org August 18, 2023 An international team of researchers (USA – University of Arkansas, UC Berkeley, Spain) theoretically considered a graphene ripple as a Brownian particle coupled to an energy storage circuit. When circuit and particle are at the same temperature, the second law forbids harvesting energy from the thermal motion of the Brownian particle, even if the circuit contains a rectifying diode. However, when the circuit contains a junction followed by two diodes wired in opposition, the approach to equilibrium may become ultraslow. Detailed balance is temporarily broken as current flows between the two diodes and charges storage capacitors. […]
New paint gives extra insulation, saving on energy, costs, and carbon emissions
Phys.org August 14. 2023 Space heating and cooling consume ~13% of global energy every year. To thermally isolate the space of concern and minimize the heat exchange with the outside environment has been recognized as one effective solution. Researchers at Stanford University developed a universal category of colorful low-emissivity paints to form bilayer coatings consisting of an infrared (IR)-reflective bottom layer and an IR-transparent top layer in colors. High mid-infrared reflectance (up to ~80%) was achieved, which is more than 10 times as conventional paints in the same colors, efficiently reducing both heat gain and loss from/to the outside environment. […]
Physicists open new path to an exotic form of superconductivity
Phys.org August 8, 2023 Understanding the interplay of band topology and electronic interactions in topological systems remains a frontier question. A team of researchers in the US (Emory University, Stanford University) predicted new interacting electronic orders emerging near higher order Van Hove singularities present in the Chern bands of the Haldane model. They classified the nature of such singularities and employed unbiased renormalization group methods that unveiled a complex landscape of electronic orders, which included ferromagnetism, density waves, and superconductivity. Importantly, they showed that repulsive interactions could stabilize the long-sought pair-density-wave state and an exotic Chern supermetal, which is a […]