Nanowerk August 27, 2021 Biphenylene network is highly conductive and may prove able to store more electrical energy than even graphene. However, their syntheses remain challenging given the lack of reliable protocols for generating nonhexagonal rings during the in-plane tiling of carbon atoms. An international team of researchers (Germany, Finland, Japan) has grown an ultraflat biphenylene network with periodically arranged four-, six-, and eight-membered rings of sp2-hybridized carbon atoms through an on-surface interpolymer dehydrofluorination (HF-zipping) reaction. The characterization of this biphenylene network by scanning probe methods reveals that it is metallic rather than a dielectric. They expect the interpolymer HF-zipping […]
Tag Archives: Advanced manufacturing
Microbially produced fibers: Stronger than steel, tougher than Kevlar
Phys.org July 21, 2021 A problem associated with recombinant spider silk fiber is the need to create β-nanocrystals, a main component of natural spider silk, which contributes to its strength. Researchers at Washington University redesigned the silk sequence by introducing amyloid sequences that have high tendency to form β-nanocrystals. They created different polymeric amyloid proteins using three well-studied amyloid sequences as representatives. The resulting proteins had less repetitive amino acid sequences than spider silk, making them easier to be produced by engineered bacteria. The longer the protein, the stronger and tougher the resulting fiber. The 128-repeat proteins resulted in a […]
Graphene additive manufacturing for flexible and printable electronics
Phys.org July 2, 2021 As a proof-of-concept researchers at Kansas State University used graphene aerosol gel ink, synthesized via an energy efficient, catalyst-free, and nonhazardous chemical precursor detonation method, such as hydrocarbons (e.g., acetylene) in the presence of controlled oxygen. They used the ink to print microsupercapacitors in interdigitated electrodes (IDEs) geometry on 25-μm thick polyimide substrates using a micro plotter. The microsupercapacitors showed an aerial capacitance of 55 μF/cm2 and volumetric capacitance of 3.25 F/cm3 at a current density of 6.0 microamp/cm2 and 20 milliamp/cm3, respectively. The printed devices did not show a significant distortion in the cyclic voltammetry […]
Growing ‘metallic wood’ to new heights
Phys.org June 29, 2021 Nanolattices exhibit attractive mechanical, energy conversion and optical properties, but it is challenging to fabricate large nanolattices while maintaining the dense regular nanometre features that enable their properties. Researchers at the University of Pennsylvania developed a crack-free self-assembly approach for fabricating centimetre-scale nickel nanolattices with much larger crack-free areas. The nanolattices have a feature size of 100 nm, a grain size of 30 nm and a tensile strength of 260 MPa, which approaches the theoretical strength limit for porous nickel. The work may advance the fabrication and applications of high-strength multifunctional porous materials…read more. TECHNICAL ARTICLE
Scientists design 3D-grown material that could speed up production of new technologies for smart buildings and robotics
Phys.org June 29, 2021 An international team of researchers (UC Berkeley, Lawrence Berkeley National Laboratory, UK) has developed a nanoparticle composite that grows into 3-D crystals. They discovered that a tiny trace of polyolefin molecules from the centrifuge tube lining had somehow entered the mix. Subsequent experiments revealed that as the toluene solvent quickly evaporates at room temperature, the polyolefin additive helps the Au-PS nanoparticles form into 3D PGNP crystals, and to grow into crystal structure and the size and shape of the 3D PGNP crystals are driven by the kinetic energy of olyolefins as they precipitate in the solution. […]
Researchers demonstrate fully recyclable printed electronics
EurekAlert April 26, 2021 Developments in transient electronics have focused on increasing the biocompatibility, whereas efforts to develop methods to recapture and reuse materials have focused on conducting materials, while neglecting other electronic materials. Researchers at Duke University have made all-carbon thin-film transistors using crystalline nanocellulose as a dielectric, carbon nanotubes as a semiconductor, graphene as a conductor and paper as a substrate. They developed a crystalline nanocellulose ink that is compatible with nanotube and graphene inks and can be written onto a paper substrate using room-temperature aerosol jet printing. The addition of mobile sodium ions to the dielectric improves […]
Scientists watch 2D puddles of electrons emerge in a 3D superconducting material
Science Daily April 12, 2021 An international team of researchers (USA – SLAC National Accelerator Laboratory, Stanford University, Colombia) synthesized high-temperature superconductor BPBO (Barium, Lead, Bismuth, Oxygen) and tested its properties, including transition temperature. The data showed electrons behaving as if they were confined to ultrathin, 2D layers or stripes within the material. The stripes were layers where electrons behave as if they are confined to 2D, puddle-like areas in the material. The distances between the puddles were short enough to allow them to behave like a superconductor. The 2D puddles emerged as the scientists carefully adjusted the temperature and […]
Researchers first to link silicon atoms on surfaces
Nanowerk March 30, 2021 Researchers in Germany have demonstrated Si–Si bond formation on Au(111) and Cu(111) surfaces by using two different monomers, each containing two silicon functional groups (CH3SiH2 or SiH3) attached to an aromatic backbone, leading to polymeric disilenes that interact with the surface. A combination of experimental and theoretical studies corroborated the formation of covalent Si–Si bonds between the long, highly ordered polymer chains with high diastereoselectivity. The reactive Si=Si bonds formally generated via double dehydrogenative coupling were stabilized via covalent Si–surface interaction. This method could be used to develop a completely new strategy for molecular changes to […]
Spintronics: New production method makes crystalline microstructures universally usable
Science Daily February 23, 2021 Based on a recently developed method that allows the fabrication of freestanding monocrystalline YIG bridges on gadolinium-gallium-garnet, researchers in Germany have developed a process that allows the transfer of monocrystalline yttrium-iron-garnet microstructures onto virtually any kind of substrate. The bridges’ spans are detached from the substrate by a dry etching process and immersed in a watery solution. Using drop-casting, the immersed YIG platelets can be transferred onto the substrate of choice, where the structures finally can be reattached and, thus, be integrated into complex devices or experimental geometries. They demonstrated that the structures retain their […]
Graphene “nano-origami” creates tiniest microchips yet
EurekAlert February 15, 2021 An international team of researchers (UK, Greece, USA – Rice University, Italy) identified and investigated different geometries of line defects in graphene and molybdenum disulfide such as standing collapsed wrinkles, folded wrinkles, and grain boundaries that exhibit distinct strain and doping. They determined the influence of the defects on local stiffness. For wrinkles of similar height, the stiffness of graphene was found to be higher than that of molybdenum disulfide by 10–15% due to stronger in-plane covalent bonding. Defects in graphene predominantly show compressive strain and increased carrier density. Defects in molybdenum disulfide predominantly show tensile […]