Phys.org December 12, 2022 Researchers at Princeton University used a lab-designed protein (ConK) which facilitated the formation of cadmium sulfide quantum dots by catalyzing the production of a reactive sulfur species from the amino acid cysteine. ConK catalyzed the desulfurization of cysteine to H2S, which was used to synthesize CdS nanocrystals in solution. The quantum dots had optical properties like those seen in chemically synthesized quantum dots. CdS nanocrystals synthesized using ConK have slower growth rates and a different growth mechanism than those synthesized using natural biomineralization pathways and have two desirable properties not observed during biomineralization using natural proteins […]
Combination of two materials creates high-performance, stretchy nanogenerator
Phys.org December 12, 2022 The intrinsically stretchable triboelectric nanogenerators (TENGs) suffer from poor performance. To address the challenge, an international team of researchers (China, USA – the Pennsylvania State University) has developed a fully stretchable TENG consisting of an intrinsically stretchable MXene/silicone elastomer and silver nanowires (Ag NWs)-graphene foam nanocomposite. The TENG exhibited high output performance (voltage, current, and power), long-term reliability, and stable electrical output under various extreme deformation conditions. It harvested the intermittent mechanical energy from human bodies to charge various energy storage units such as commercial capacitors for driving wearable electronic devices. They demonstrated the systems in […]
Designing self-assembling ‘smart materials’
Science Daily December 12, 2022 The role of hydrodynamic interactions (HIs) play in the self-organization of colloidal suspensions and biological solutions has remained elusive particularly for charged soft matter systems. Researchers in Japan studied the role of HIs in the self-assembly of oppositely charged colloidal particles, which is a promising candidate for electrical tunable soft materials. In many-body HIs and the coupling between the colloid, ion, and fluid motions they found that, under a constant electric field, oppositely charged colloidal particles formed clusters and percolated into a gel network. They revealed that the cluster-forming tendency originates from the incompressibility-induced “inverse […]
Growing a tiny metallic snowflake
Nanowerk December 10, 2022 Nanoscale structures can aid electronic manufacturing, make materials stronger yet lighter, or aid environmental clean-ups by binding to toxins. An international team of researchers (Australia, New Zealand) developed an extraction method achieved by applying a voltage to the liquid metal solution while vacuum filtrating. The resulting crystals can have intricate morphologies like snowflakes. They used the low-melting-temperature Ga as a “metallic solvent” to synthesize a range of flake-like Zn crystals. They extracted the metallic crystals from the liquid metal solvent by reducing its surface tension using a combination of electrocapillary modulation and vacuum filtration. The crystals […]
International research team creates previously unknown nitrogen compounds
Phys.org December 9, 2022 Non-metal nitrides contain structural units whose existence could not be empirically proven before. An international team of researchers (Germany, Sweden, USA – University of Chicago, France) synthesized previously unknown modification of the phosphorus nitride P₃N₅ at a pressure of 72 gigapascals. At 134 gigapascals, the phosphorus nitride PN₂ formed in the diamond anvil cell. They discovered that a key reason for this extreme strength was that the crystal structures of δ-P₃N₅ and PN₂ consist of a dense network of PN₆ octahedra with a phosphorus atom surrounded by six nitrogen atoms. The polymorph δ-P₃N₅ transformed into another […]
Molecular shape-shifting: New theory on autonomous remodeling of structures
Phys.org December 13, 2022 The capability to self-organize, like living systems, can only be afforded in non-equilibrium conditions, as evident from the energy-consuming nature of dynamical processes. To achieve automated dynamical control of such self-assembled structures and transitions between them, it is necessary to identify the fundamental aspects of non-equilibrium dynamics that can enable such processes. An international team of researchers (Germany, UK) identified programmable non-reciprocal interactions as a tool to achieve such functionalities. The design rule was composed of reciprocal interactions that led to the equilibrium assembly of the different structures, through a process denoted as multifarious self-assembly, and […]
New battery technology has potential to significantly reduce energy storage costs
Science Daily December 7, 2022 The issues arising from the low S mass loading and poor cycling stability caused by the shuttle effect of polysulfides seriously limit the operating capacity and cycling capability of room-temperature sodium–sulfur (RT-Na/S) batteries. An international team of researchers (China, Australia) synthesized sulfur-doped graphene frameworks supporting atomically dispersed 2H-MoS2 and Mo1 (S@MoS2-Mo1/SGF) with a record high sulfur mass loading of 80.9 wt.% as an integrated dual active sites cathode for RT-Na/S batteries. They displayed unprecedented cyclic stability with a high initial capacity and a low-capacity fading rate of 0.05% per cycle over 1000 cycles. Experimental and […]
Paper-thin solar cell can turn any surface into a power source (w/video)
Nanowerk December 10, 2022 To date, demonstrations of ultra-thin photovoltaics have been limited to small-scale devices, often prepared on glass carrier substrates with only a few layers solution-processed. Researchers at MIT have demonstrated large-area, ultra-thin organic photovoltaic (PV) modules produced with scalable solution-based printing processes for all layers. They were transferred onto lightweight and high-strength composite fabrics, resulting in durable fabric-PV systems ∼50 microns thin, weighing under 1 gram over the module are, and having a specific power of 370 W kg−1. Integration of the ultra-thin modules onto composite fabrics lends mechanical resilience to allow the fabric-PV systems to maintain […]
Scientists map heat beneath Antarctica’s icesheets
Phys.org December 13, 2022 Geothermal heat flow (GHF) can reveal past and present plate tectonic processes. In Antarctica, GHF has further consequences in predicting the response of ice sheets to climate change. In a review article an international team of researchers (Australia, Germany, USA – Stony Brook University, Colorado College) discuss variations in Antarctic GHF models based on geophysical methods and draw insights into tectonics and GHF model usage for ice sheet modelling. The inferred GHF at continental scale for West Antarctica points to numerous contributing influences, including non-steady state neotectonic processes. Combined influences cause especially high values in the […]
Signals from the ionosphere could improve tsunami forecasts
Phys.org December 12, 2022 Acoustic-gravity waves propagated by the eruption and tsunami caused global complex ionospheric disturbances. Researchers at the University of Washington studied the nature of the perturbations from Global Navigation Satellite System observables over the southwestern Pacific. After processing data from 818 ground stations, they detected supersonic acoustic waves, Lamb waves, and tsunamis, with filtered magnitudes between 1 and 7 Total Electron Content units. Phase arrivals appeared super positioned up to ∼1,000 km from HTHH and were distinct by ∼2,200 km. Within ∼2,200 km, signals had an initial low-frequency pulse that transitioned to higher frequencies. They found the […]