Nanowerk August 24, 2020 In a conventional lens an increase in refraction index increases the field of view in proportion to the flatness of the lens. To image with a single element over a wide field of view an international team of researchers (Brazil, UK, China) used photolithography to design a lens consisting of a single nanometric layer of silicon on arrays of nanoposts that interact with light. The resulting metalens mimics a totally flat lens with an infinite refraction index, which could not be obtained with a conventional lens. It has a field of view, which ideally can reach […]
Storing information in antiferromagnetic materials
EurekAlert August 24, 2020 An international team of researchers (Germany, France, Japan, Czech Republic) has shown that information storage in antiferromagnetic materials is fundamentally possible, and how efficiently information can be written electrically in insulating antiferromagnetic materials. For their measurements, the researchers used the antiferromagnetic insulator Cobalt oxide CoO – a model material that paves the way for applications. The result: Currents are much more efficient than magnetic fields to manipulate antiferromagnetic materials. This discovery opens the way toward applications ranging from smart cards that cannot be erased by external magnetic fields to ultrafast computers – thanks to the superior […]
Study offers new insights for sun-gathering technologies
Phys.org August 24, 2020 The direct integration of electrocatalysts with photovoltaic materials provides a strategy to photoelectrochemically power chemical transformations and store intermittent solar energy as fuels. Researchers at the Arizona State University highlight how optical and electrochemical characterization techniques can be coupled with structural information to address to what extent does a selected electrocatalytic coating screen photons from reaching the underlying photovoltaic; coating layers contribute to photocurrent production; and are relatively high or low loadings of catalytic sites advantageous. They used p-type gallium phosphide semiconductor that is interfaced with cobalt porphyrin hydrogen evolution reaction catalysts. Experimental techniques can likely […]
Thin layer protects battery, allows cold charging
Science Daily August 26, 2020 Stable operation of rechargeable lithium-based batteries at low temperatures is plagued by dendritic Li plating and unstable solid–electrolyte interphase (SEI). A team of researchers in the US (Pennsylvania State University, Argonne National Laboratory, Ohio University, University of Illinois) used a self-assembled monolayer of electrochemically active molecules on current collectors that regulates the nanostructure and composition of the SEI and deposition morphology of Li metal anodes to achieve high performance. A multilayer SEI that contains a lithium fluoride-rich inner phase and amorphous outer layer effectively seals the Li surface, in contrast to the conventional SEI, which […]
Wireless device makes clean fuel from sunlight, carbon dioxide and water
TechXplore August 24, 2020 An international team of researchers (UK, Japan) has developed a technology that integrates lanthanum- and rhodium-doped SrTiO3 (SrTiO3:La,Rh) and molybdenum-doped BiVO4 (BiVO4:Mo) light absorbers modified by phosphonated Co(II) bis(terpyridine) and RuO2 catalysts onto a gold layer. The monolithic device provides a solar-to-formate conversion efficiency of 0.08 ± 0.01% with a selectivity for formate of 97 ± 3%. It produced almost no by-products. The new technology is more robust and produces clean fuel that is easier to store and shows potential for producing fuel products at scale…read more. TECHNICAL ARTICLE
Top 10 Science and Technology Inventions for the Week of August 21, 2020
01. First ever observation of ‘time crystals’ interacting 02. A new iron based super elastic alloy capable of withstanding extreme temperatures 03. Scientists use photons as threads to weave novel forms of matter 04. Watching electrons harvest light at the nanoscale 05. Sculpting a Waveguide with Light 06. Researchers capture footage of fluid behaving like a solid 07. Efficient Off-Grid Power, After the Sun Sets 08. Trace vapor generator for detecting explosives, narcotics 09. Ultrafast electrons in magnetic oxides: A new direction for spintronics? 10. IARPA pursues advanced radio eavesdropping defenses And others… A Battery That’s Tough Enough To Take […]
A Battery That’s Tough Enough To Take Structural Loads
IEEE Spectrum August 19, 2020 The main problem to overcome in load-bearing batteries is the tradeoff between electrochemical performance and mechanical strength. A team of researchers in the US (University of Michigan, Texas A&M University) used a solid electrolyte and covered the electrodes with a membrane whose nanostructure of fibers is derived from Kevlar. That makes the membrane tough enough to suppress the growth of dendrites. The researchers do not announce how many watt-hours his prototype stores per gram. Drones and other autonomous robots may benefit from the technology as their range is severely chained to their battery capacity…read more. […]
Black silicon photodetector breaks the 100% efficiency limit
Phys.org August 14, 2020 Ultraviolet sensors are utilized in numerous fields although their performance is surprisingly poor. An international team of researchers (Finland, Spain, Germany) used a nanostructured silicon photodiode with self-induced junction to demonstrate that it is possible to make a device with a certified external quantum efficiency above 130% in UV range without external amplification. They showed that the high efficiency is based on effective utilization of multiple carrier generation by impact ionization taking place in the nanostructures. While the results can readily have a significant impact on the UV-sensor industry, the underlying technological concept can be applied […]
DOD’s IT supply chain has dozens of suppliers from China, report finds
FedScoop August 14, 2020 According to a report from the data analytics firm Govini, in a sample of more than 1,000 prime defense contractors’ supply chains there are several dozen Chinese suppliers from the IT, software, and telecommunications equipment industries. Federal government, including the DOD, has been required by law to remove certain Chinese-owned technology firms from it its supply chains as of Aug. 13. The risks of foreign — and Chinese, in particular — goods in the defense supply chain is greatest in the IT and software industries…read more.
Efficient Off-Grid Power, After the Sun Sets
Optics and Photonics August 19, 2020 An international team of researchers (USA – Stanford, Israel) analyzed the basic thermodynamics of a heat engine, with the hot side under the roof and the top of the roof radiating thermal energy out into the environment. They developed models to maximize the amount of electrical power generated for various temperature gradients. The team’s design for a nighttime power generator would occupy a rooftop area of 1 m2. It incorporates a radiative emitting panel, a state-of-the-art TEG made of metal alloy, and a heat sink, with radiation shields and insulative pegs to reduce radiative […]