Phys.org March 22, 2024 Nanomaterials exhibit excitonic quantum processes occurring at room temperature. However, low dimensionality imposes strict requirements for conventional optical excitation. Researchers in Japan found that exciton transfer in carbon-nanotube/tungsten-diselenide heterostructures occur when alignment could be systematically varied. The mixed-dimensional heterostructures displayed a pronounced exciton reservoir effect where the longer-lifetime excitons within the two-dimensional semiconductor were funneled into carbon nanotubes through diffusion. The new excitation pathway presented several advantages, including larger absorption areas, broadband spectral response, and polarization-independent efficiency. When band alignment was resonant, they observed substantially more efficient excitation via tungsten diselenide compared to direct excitation of […]
Bendable energy storage materials by cool science
Science Daily March 19, 2024 Mesoporous metal oxides exhibit excellent physicochemical properties and are widely used in various fields, including energy storage/conversion, catalysis, and sensors. Although several soft-template approaches are reported, high-temperature calcination for both metal oxide formation and template removal is necessary, which limits direct synthesis on a plastic substrate for flexible devices. Researchers in South Korea developed a universal synthetic approach that combines thermal activation and oxygen plasma to synthesize diverse mesoporous metal oxides (V2O5, V6O13, TiO2, Nb2O5, WO3, and MoO3) at low temperatures (150–200 °C), which could be applied to a flexible polymeric substrate. To demonstrate their […]
Deep Earth electrical grid mystery solved
Science Daily March 20, 2024 Extracellular electron transfer (EET) via microbial nanowires drives important environmental processes and biotechnological applications for bioenergy, bioremediation, and bioelectronics. However, the process is not clear. An international team of researchers (USA – Yale University, Portugal) showed that Geobacter sulfurreducens periplasmic cytochromes PpcABCDE inject electrons directly into OmcS nanowires by binding transiently with differing efficiencies, with the least-abundant cytochrome (PpcC) showing the highest efficiency. This defined nanowire-charging pathway was evolutionarily conserved in phylogenetically diverse bacteria capable of EET. OmcS heme reduction potentials were within 200 mV of each other, with a midpoint 82 mV-higher than reported previously. […]
Electron-bending effect could boost computer memory
Phys.org March 26, 2024 Magnets with a rutile crystal structure may be possible platform for a collinear-antiferromagnetism-induced anomalous Hall effect (AHE). RuO2 is a prototypical candidate material, however the AHE is prohibited at zero field by symmetry. An international team of researchers (Japan, China) showed AHE at zero field in Cr-doped rutile, Ru0.8Cr0.2O2. Their calculations indicated that appropriate doping of Cr at Ru sites reconstructed the collinear antiferromagnetism in RuO2, resulting in a rotation of the Néel vector from [001] to [110] while maintaining a collinear antiferromagnetic state. The AHE with vanishing net moment in the Ru0.8Cr0.2O2 exhibited an orientation […]
Engineers find a new way to convert carbon dioxide into useful products
MIT News March 27, 2024 For electrochemical reduction of carbon dioxide with a small-molecule catalyst, the catalyst must be proximal to an electrode surface. Efforts to immobilize molecular catalysts on electrodes have been stymied by the need to optimize the immobilization chemistries on a case-by-case basis. Researchers at MIT applied DNA as a molecular-scale “Velcro” to investigate the tethering of three porphyrin-based catalysts to electrodes improving both the stability of the catalysts and their Faradaic efficiencies (FEs). Immobilization resulted in higher catalyst stability at relevant potentials. Lower overpotentials were required for the generation of CO. High FE for CO generation […]
Moebius rings enable new ways to control light in twisted spaces
Nanowerk March 21, 2024 Modulation of topological phase transition has been realized in Euclidean systems. However, the spin-controlled topological phase transition in non-Euclidean space has not yet been explored. Researchers in China proposed a non-Euclidean configuration based on Möbius rings, and demonstrated the spin-controlled transition between the topological edge state and the bulk state. They utilized 8π period Möbius rings to construct both one-dimensional and two-dimensional coupled resonator optical waveguide (CROW) configurations which supported topological edge states excited by circularly polarized light of a specific handedness, while forbidding the excitation of topological modes by light of the opposite handedness. This […]
New research area promotes both quantum computing and cognitive science
Phys.org March 26, 2024 Quantum biology applies quantum mechanics to biological systems at the molecular scale. Molecular quantum computing explores the degrees of freedom of molecules that can be used to produce quantum coherence. Cognitive science focuses on understanding how learning processes are realized, particularly within the human brain. An international team of researchers (US, USA – New Jersey Institute of Technology, Morgan State University) reviewed progress in quantum biology, molecular quantum computing, and quantum theory in cognitive science. Based on their analysis and review, they highlighted that molecular quantum computing could be an important bridging research area between quantum […]
Pushing back the limits of optical imaging by processing trillions of frames per second
Phys.org March 25, 2024 Despite real-time femtophotography advantages over conventional multi-shot approaches, existing techniques confront restricted imaging speed or degraded data quality by the deployed optoelectronic devices application scope, acquisition accuracy, and hindered by the limitations in the acquirable information imposed by the sensing models. An international team of researchers (Canada, France) overcame these challenges by developing swept coded aperture real-time femtophotography (SCARF). This enables all-optical ultrafast sweeping of a static coded aperture during the recording of an ultrafast event, bringing full sequence encoding of up to 156.3 THz to every pixel on a CCD camera. They demonstrated SCARF’s single-shot ultrafast […]
Quantum interference could lead to smaller, faster, and more energy-efficient transistors
Science Daily March 25, 2024 Quantum behaviour presents an unresolved challenge facing electronics at the few-nanometre scale: resistive channels start leaking owing to quantum tunnelling which affect the performance of nanoscale transistors, with direct source–drain tunnelling degrading switching ratios. The strategy to mitigate quantum effects has been to increase device complexity. An international team of researchers (UK, Canada, Italy) demonstrated how the performance of molecular transistors was improved when the resistive channel contained two destructively interfering waves. They used a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor to demonstrate a >104 conductance-switching ratio, a subthreshold swing at the […]
Research team creates global roadmap to advance printable sensors for sustainability and quality of life
Phys.org March 25, 2024 The dissemination of sensors could advance the sustainability and quality of our lives. Sensors based on printable electronic materials offer the ideal platform: they can be fabricated through simple methods (e.g., printing and coating) and are compatible with high-throughput roll-to-roll processing; printable electronic materials often allow the fabrication of sensors on flexible/stretchable/biodegradable substrates. Device innovations to enhance their ability to transduce external stimuli—light, ionizing radiation, pressure, strain, force, temperature, gas, vapours, humidity, and other chemical and biological analytes are necessary. An international team of researchers (Canada, Italy, USA – University of Wisconsin, Northwestern University, the Netherlands, […]