Science Daily July 19, 2023 In traditional metallurgical design for fatigue resistance in metals, microstructures are developed to either arrest or slow the progression of cracks. Crack growth is assumed to be irreversible. By contrast, in other material classes, there is a compelling alternative based on latent healing mechanisms and damage. A team of researchers in the US (Sandia National Laboratory, Texas A&M University, University of Tennessee) has shown that fatigue cracks in pure metals can undergo intrinsic self-healing. They directly observed the early progression of nanoscale fatigue cracks, and as expected, the cracks advanced, deflected and arrested at local […]
Team creates simple superconducting device that could dramatically cut energy use in computing
Phys.org July 28, 2023 Accomplishing unequal supercurrents in the forward and backward directions in superconductors would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called the superconducting (SC) diode effect. An international team of researchers (USA – MIT, US Army DEVCOM, High School (Alabama, Washington). Switzerland, Spain) demonstrated the strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external small magnetic fields. Interfacing the SC layer with a ferromagnetic semiconductor EuS, they further accomplished the nonvolatile SC diode effect reaching an efficiency of 65%. By careful control experiments and theoretical modeling, they demonstrated […]
Turning bacteria into solar factories with semiconductor nanoclusters
Nanowerk July 28, 2023 Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the periplasmic space, characterized by its confinement and the presence of numerous enzymes and peptidoglycans, offers additional opportunities for biomineralization, allowing for nongenetic modulation interfaces. A team of researchers in the US (University of Chicago, Argonne National Laboratory, National Renewal Energy Laboratory) demonstrated semiconductor nanocluster precipitation containing single- and multiple-metal elements within the periplasm. The periplasmic semiconductors were metastable and displayed defect-dominant fluorescent properties. The defect-rich (i.e., the low-grade) semiconductor nanoclusters produced in situ could still […]
Top 10 Science and Technology Inventions for the Week of July 28, 2023
01. Allowing robots to explore on their own 02. Aluminum materials show promising performance for safer, cheaper, more powerful batteries 03. Device makes hydrogen from sunlight with record efficiency 04. Insights into designing advanced stimuli-responsive porous materials 05. Lights could be the future of the internet and data transmission 06. New study reveals remarkable impact of intrinsic spin shielding in platinum-rare earth alloys on electrocatalysis 07. A new type of quantum bit in semiconductor nanostructures 08. Non-native English speaking scientists work much harder just to keep up, global research reveals 09. A novel approach for balancing properties in composite materials […]
Allowing robots to explore on their own
Science Daily July 21, 2023 Researchers at Carnegie Mellon University has proposed dual-resolution scheme to achieve time-efficient autonomous exploration with one or many robots using a high-resolution local map of the robot’s immediate vicinity and a low-resolution global map of the remaining areas of the environment. The high-resolution bounded local map ensures that the robots observe the entire region in detail and the computation burden is bounded. The low-resolution global map directs the robot to explore the broad space and only requires lightweight computation and low bandwidth to communicate among the robots. Their paper shows the strength of this approach […]
Aluminum materials show promising performance for safer, cheaper, more powerful batteries
Science Daily July 19, 2023 Metal negative electrodes that alloy with lithium have high theoretical charge storage capacity and are ideal candidates for developing high-energy rechargeable batteries. However, such electrode materials show limited reversibility in Li-ion batteries with standard non-aqueous liquid electrolyte solutions. A team of researchers in the US (Georgia Institute of Technology, industry) used non-pre-lithiated aluminum-foil-based negative electrodes with engineered microstructures in an all-solid-state Li-ion cell configuration. When a 30-μm-thick Al94.5In5.5 negative electrode is combined with a Li6PS5Cl solid-state electrolyte and a LiNi0.6Mn0.2Co0.2O2-based positive electrode, lab-scale cells delivered hundreds of stable cycles with practically relevant areal capacities at […]
Device makes hydrogen from sunlight with record efficiency
Science Daily July 20, 2023 An international team of researchers (USA – Rice University, National Renewable Energy Laboratory, Lawrence Berkeley National Laboratory, Germany, France) designed and fabricated a conductive adhesive-barrier (CAB) that translates >99% of photoelectric power to chemical reactions. The CAB enabled halide perovskite-based photoelectrochemical cells with two different architectures that exhibited record STH efficiencies. The first, a co-planar photocathode-photoanode architecture, achieved an STH efficiency of 13.4% and 16.3 h to t60, solely limited by the hygroscopic hole transport layer in the n-i-p device. The second was formed using a monolithic stacked silicon-perovskite tandem, with a peak STH efficiency of […]
Insights into designing advanced stimuli-responsive porous materials
Phys.org July 21, 2023 MOFs which possess a high degree of crystallinity and a large surface area with tunable inorganic nodes and organic linkers. The adsorption in MOFs changes the crystalline structure and elastic moduli. Thus, the coexistence of adsorbed/desorbed sites makes the host matrices elastically heterogeneous. To show the asymmetric role of elastic heterogeneity in the adsorption–desorption transition researchers in Japan constructed a minimal model incorporating adsorption-induced lattice expansion/contraction and an increase/decrease in the elastic moduli. They found that the transition was hindered by the entropic and energetic effects which become asymmetric in the adsorption process and desorption process, […]
Lights could be the future of the internet and data transmission
Phys.org July 25, 2023 The modulation characteristics of perovskite LEDs are not clear. An international team of researchers (UK, Switzerland) has developed a new approach for realizing fast perovskite photonic sources on silicon based on tailoring alkylammonium cations in perovskite systems. They showed the recombination behaviour of charged species at various carrier density regimes relevant for their modulation performance. By integrating a Fabry–Pérot microcavity on silicon, they demonstrated perovskite devices with efficient light outcoupling and achieved device modulation bandwidths of up to 42.6 MHz and data rates above 50 Mbps, with further analysis suggesting that the bandwidth may exceed gigahertz levels. According […]
New study reveals remarkable impact of intrinsic spin shielding in platinum-rare earth alloys on electrocatalysis
Phys.org July 24. 2023 Researchers in China introduced platinum–rare earth metal-based alloy catalyst, Pt2Gd, to reveal the role of spin configurations in the catalytic activity of materials. The catalyst exhibited a unique intrinsic spin reconfiguration because of interactions between the Gd-4f and Pt-5d orbitals. The adsorption and desorption of the oxygen species were optimized by modifying the spin symmetry and electronic structures of the material for increased oxygen reduction reaction (ORR) efficiency. The Pt2Gd alloy exhibited a half-wave potential, and a superior mass activity, and higher durability than conventional Pt/C catalysts. Theoretical calculations have proved that the spin shielding effect […]