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 […]
Author Archives: Hema Viswanath
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 […]
Top 10 Science and Technology Inventions for the Week of March 22, 2024
01. Cracking the quantum code: Simulations track entangled quarks 02. High-quality microwave signals generated from tiny photonic chip 03. New method enables synthesis of hundreds of new 2D materials 04. Photon-like electrons in a four-dimensional world discovered in a real material 05. Projection mapping leaves the darkness behind 06. Quantum dance to the beat of a drum: Researchers observe how energy of single electron is tuned by surrounding atoms 07. Researchers achieve >99% photoluminescence quantum yield in metal nanoclusters 08. Researchers develop novel ‘super-tetragonal’ sacrificial layer for freestanding oxide membranes 09. Researchers discover new yttrium-hydrogen compounds with implications for high-pressure […]
Backyard insect inspires invisibility devices, next gen tech
Phys.org March 18, 2024 The leafhoppers cover their body surfaces with brochosomes, buckyball-shaped, nanoscopic spheroids with through-holes distributed across their surfaces, representing a class of deployable optical materials that are rare in nature. A team of researchers in the US (University of Pennsylvania, Carnegie Mellon University) investigated the optical form-to-function relationship of brochosomes and demonstrated that the hierarchical geometries of brochosomes are engineered within a narrow size range with through-hole architecture to significantly reduce light reflection. They showed that the diameters of brochosomes are engineered to maximize broadband light scattering, while the secondary through-holes are designed to function as short-wavelength, […]
Cracking the quantum code: Simulations track entangled quarks
Phys.org March 19, 2024 The cascades of particles produced by the fragmentation of supposedly entangled particles emitted from high energy particle collisions should allow testing the real-time response of the QCD vacuum disturbed by the propagation of high-momentum color charges. A team of researchers in the US (Stony Brook University, Brook Haven National Laboratory) developed fully quantum simulations of a massive Schwinger model coupled to external sources representing quark and antiquark jets as produced in e+e− annihilation. They studied the modification of the vacuum chiral condensate by the propagating jets and the quantum entanglement between the fragmenting jets. Their results […]
Enabling a New Paradigm for Flexible, Point of Need Design and Manufacturing
DARPA News March 11, 2024 DARPA’s new Rubble to Rockets (R2) program aims to overcome current limitations to manufacturing in supply chain-denied environments by developing production and design approaches that can accommodate widely variable input materials. Performers will focus on creating an inexpensive, flexible, and robust platform for the production and characterization of raw material for use in structural fabrication. DARPA hypothesizes that the analytical framework would allow for rapid upgrades to incorporate the growing number of new material developments and fabrication methods, thus significantly reducing adoption risk that traditionally take decades to retire. An R2 Industry Day is scheduled […]