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, […]
Researchers harness the sun to produce hydrogen gas from water
Phys.org March 26, 2024 To understand the factors that promote bimetallic H–H coupling researchers at the University of North Carolina at Chapel Hill, USA, subjected molecular iridium catalysts to undergo photoelectrochemical dihydrogen (H2) evolution via a bimolecular mechanism. Covalently tethered diiridium catalysts evolved H2 from neutral water faster than monometallic catalysts, even at lower overpotential. The unexpected origin of this improvement was non-covalent supramolecular self-assembly into nanoscale aggregates that efficiently harvested light and form H–H bonds. Monometallic catalysts containing long-chain alkane substituents leveraged the self-assembly to evolve H2 from neutral water at low overpotential and with rates close to the […]
Researchers take major step toward developing next-generation solar cells
Science Daily March 22, 2024 The efficiency of p–i–n perovskite solar cells fabricated in air still lags behind those made in an inert atmosphere. An international team of researchers (China, USA-University of Colorado) introduced an ionic pair stabilizer, dimethylammonium formate (DMAFo), into the perovskite precursor solution to prevent the degradation of perovskite precursors. It inhibited the oxidization of iodide ions and deprotonation of organic cations, improved the crystallinity and reduced defects in the resulting perovskite films. They showed the generation of additional p-type defects during ambient air fabrication that suggested the need for improving bulk properties of the perovskite film […]
Ultrafast plasmonics for all-optical switching and pulsed lasers
Phys.org March 25, 2024 The recent developments in the fabrication and characterization of plasmonic nanostructures have stimulated continuous effects in the search for their potential applications in the photonic fields. In this review article an international team of researchers (India, USA – Vanderbilt University, San Diego State University, Canada) concentrated on the role of plasmonics in photonics, covering recent advances in ultrafast plasmonic materials with focus on all-optical switching. They discussed fundamental phenomena of plasmonic light–matter interaction and plasmon dynamics elaborating on the ultrafast processes unraveled by both experimental and theoretical methods, along with a comprehensive illustration of leveraging ultrafast […]
The world is one step closer to secure quantum communication on a global scale
Phys.org March 25, 2024 An on-demand source of bright entangled photon pairs is needed for quantum key distribution (QKD) and quantum repeaters. The generation of such pairs is based on spontaneous parametric down-conversion (SPDC) in non-linear crystals. However, SPDC pair extraction efficiency is very limited when operating at near-unity fidelity. In principle quantum dots in photonic nanostructures can overcome this limit, but the devices with high entanglement fidelity have low pair extraction efficiency. An international team of researchers (Canada, the Netherlands, Sweden) has demonstrated a measured peak entanglement fidelity of 97.5% ± 0.8% and pair extraction efficiency of 0.65% from an InAsP […]