Phys.org November 19, 2024 Organic mixed ionic-electronic conductors (OMIECs) have better properties than inorganic counterparts for biosensing, soft-robotics, neuromorphic computing, and smart medicine. However, slow ion transport relative to charge transport in these materials is a limiting factor. Researchers at Washington State University demonstrated that hydrophilic molecules local to an interfacial OMIEC nanochannel could accelerate ion transport with ion mobilities surpassing electrophoretic transport by more than an order of magnitude. Ion access to the interfacial channel could be gated through local surface energy. They applied the mechanism in a novel sensing device, which electronically detected and characterized chemical reaction dynamics […]
Tag Archives: S&T USA
MIT engineers make converting CO2 into useful products more practical
MIT News November 13, 2024 Electrochemical CO2 reduction has emerged as a promising CO2 utilization technology, with Gas Diffusion Electrodes becoming the predominant architecture to maximize performance. The electrodes must maintain robust hydrophobicity to prevent flooding, while also ensuring high conductivity to minimize ohmic losses. Researchers at MIT demonstrated a hierarchically conductive electrode architecture which overcame the scaling limitations by employing inter-woven microscale conductors within a hydrophobic expanded Polytetrafluoroethylene membrane. They developed a model which captured the spatial variability in voltage and product distribution on electrodes due to ohmic losses and used it to rationally design the hierarchical architecture which […]
Physicists reveal how layers and twists impact graphene’s optical conductivity
Phys.org November , 2024 An international team of researchers (USA – Florida State University, China) explored the advantages of moiré superlattices in twisted bilayer graphene (TBG) aligned with hexagonal boron nitride (hBN) for passively enhancing optical conductivity in the low-energy regime. To probe the local optical response of TBG/hBN double-moiré lattices, they used infrared nano-imaging in conjunction with nanocurrent imaging to examine local optical conductivity over a wide range of TBG twist angles. They showed that interband transitions associated with the multiple moiré flat and dispersive bands produced tunable transparent IR responses even at finite carrier densities, which is in […]
Scientists capture images of a new quantum phase in electron molecular crystals
Phys.org November 17, 2024 Semiconductor Moiré superlattices provide a versatile platform to engineer quantum solids composed of artificial atoms on moiré sites. Previous studies have mostly focused on the simplest correlated quantum solid—the Fermi-Hubbard model—in which intra-atom interactions are simplified to a single onsite repulsion energy. An international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, MIT, University of Arizona, Japan) experimentally observed Wigner molecular crystals emerging from multielectron artificial atoms in twisted bilayer tungsten disulfide moiré superlattices. Using scanning tunneling microscopy, they demonstrated that Wigner molecules appeared in multielectron artificial atoms when Coulomb interactions dominated. The […]
Scientist develops new equation to better predict behavior of atmospheric rivers
Phys.org November 4, 2024 Poleward water vapor transport in the midlatitudes mainly occurs in meandering filaments of intense water vapor transport, spanning thousands of kilometers long and hundreds of kilometers wide and moving eastward. The water vapor filaments, known as atmospheric rivers (ARs), can cause extreme wind gusts, intense precipitation, and flooding along densely populated coastal regions. Many recent studies about ARs focused on the statistical analyses of ARs, but a process-level understanding of ARs remains elusive. A team of researchers in the US (Argonne National Laboratory, University of Chicago) showed that ARs are streams of air with enhanced vapor […]
Unlocking next-gen chip efficiency: Researchers confirm thermal insights for tiny circuits
Phys.org November 4, 2024 As metallic nanostructures shrink towards the size of the electronic mean free path, thermal conductivity decreases due to increased electronic scattering rates. Matthiessen’s rule is commonly applied to assess changes in electron scattering rates, although this rule has not been validated experimentally at typical operating temperatures for most of the electronic systems. A team of researchers in the US (University of Virginia, University of Rhode Island, Oak Ridge National Laboratory, Intel Corporation) experimentally evaluated the validity of Matthiessen’s rule in determining the thermal conductivity of thin metal films by measuring the in-plane thermal conductivity and electronic […]
Chemists just broke a 100-year-old rule and say it’s time to rewrite the textbooks
Phys.org October 31, 204 One hundred years ago, Julius Bredt published an observation that certain molecules that constrained several adjacent carbon centers in a particular nonplanar arrangement could not form double bonds between them. These hypothetical double bonds became known as “anti-Bredt” olefins, and the doctrine that they were inaccessible remains widespread even with the occasional hint to the contrary. Researchers at UCLA reported a general strategy to prepare these olefins as fleeting intermediates that could be captured in cycloaddition reactions. The protocol relies on the driving force of silicon-fluorine bond formation from a precursor, which is akin to approaches […]
Engineered bacterial protein offers efficient rare earth metal separation
Phys.org October 28, 2024 Elucidating details of biology’s selective uptake and trafficking of rare earth elements, particularly the lanthanides, has the potential to inspire sustainable biomolecular separations of these essential metals for many modern technologies. Researchers at The Pennsylvania State University biochemically and structurally characterized Methylobacterium (Methylorubrum) extorquens LanD from a bacterial gene cluster for lanthanide uptake. The protein provided only four ligands at its surface-exposed lanthanide-binding site, allowing for metal-centered protein dimerization that favored the largest lanthanide, LaIII. Selective dimerization enriched high-value PrIII and NdIII relative to low-value LaIII and CeIII in an all-aqueous process, achieved higher separation factors […]
MXene nanomaterials enable wireless charging in textiles
Nanowerk October 31, 2024 Due to their high conductivity, electrochemically active surface, and ability to produce additive-free coatings from aqueous inks, MXenes are an ideal material to integrate into textiles to add functionality as well as generate and store electrical energy. A team of researchers in the US (Drexel University, industry, University of Pennsylvania, Veterans Affairs Medical Center, Philadelphia) integrated MXenes into wireless charging coils printed onto textiles, serving as a conductive adhesive between MXene textile components. The MXene coils could power MXene-textile supercapacitors, allowing electromyography measurements with epidermal MXene electrodes and active heating with printed MXene-textile filaments. The on-garment […]
New method successfully recycles carbon fiber composite into reusable materials
Phys.org October 31, 2024 Carbon fiber reinforced polymers (CFRPs, or composites) are increasingly replacing traditional manufacturing materials used in the automobile, aerospace, and energy sectors. With this shift, a team of researchers in the US (University of Southern California, University of Kansas) developed an end-of-life processes for CFRPs and demonstrated a strategy to upcycle pre- and postconsumer polystyrene-containing CFRPs, cross-linked with unsaturated polyesters or vinyl esters, to benzoic acid. The thermoset matrix was upgraded via biocatalysis utilizing an engineered strain of the filamentous fungus Aspergillus nidulans, which gave access to valuable secondary metabolites in high yields. Reactions were engineered to […]