Nanowire Fabric Research Articles

Multifunctional Silver Nanowire Fabric Reinforced by Hot Pressing for Electromagnetic Interference Shielding, Electric Heating, and Sensing.

Durability and multifunctionality are crucial considerations in the realm of electronic textiles. Herein, a hot-pressing process has been developed to enhance the fixation of silver nanowires (AgNWs) on polyethylene terephthalate (PET) fabric. The conductivity, electromagnetic shielding, and electric heating properties of the hot-pressed fabric were measured to demonstrate the effectiveness of the hot-pressing process. The conductivity of the hot-pressed fabric (180 °C for 90 s) was found to be 464.2 S/m, while that of the fabric without hot pressing was 94.9 S/m. The washed hot-pressed fabric was able to provide a maximum electromagnetic shielding of 17 dB, a negative strain sensing performance (the ΔR/R0 of the hot-pressed fabric was maintained at -15%), and an outstanding electric heating property (the temperature reached 110 °C at a current of 0.08 A). This AgNW fabric holds great potential for use in multi-functional wearable devices, and the hot-pressing process improved its stability and durability, making it suitable for industrial production.

Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

Resistance measurements were performed on Bi2Sr2CaCu2O8+δ (Bi-2212) fabric-like nanowire networks or nanofiber mats in the temperature interval 3 K ≤T≤ 300 K. The nanowire fabrics were prepared by means of electrospinning, and consist of long (up to 100 μm) individual nanowires with a mean diameter of 250 nm. The microstructure of the nanowire network fiber mats and of the individual nanowires was thoroughly characterized by electron microscopy showing that the nanowires can be as thin as a single Bi-2212 grain. The polycrystalline nanowires are found to have a texture in the direction of the original polymer nanowire. The overall structure of the nanofiber mats is characterized by numerous interconnects among the nanowires, which enable current flow across the whole sample. The fluctuation-induced conductivity (excess conductivity) above the superconducting transition temperature, Tc, was analyzed using the Aslamzov-Larkin model. Four distinct fluctuation regimes (short-wave, two-dimensional, three-dimensional and critical fluctuation regimes) could be identified in the Bi-2212 nanowire fabric samples. These regimes in such nanowire network samples are discussed in detail for the first time. Based on this analysis, we determine several superconducting parameters from the resistance data.

Laser-induced plasmonic heating in copper nanowire fabric as a photothermal catalytic reactor

Metallic nanostructures possessing higher surface-to-volume ratio provide a more accessible surface to catalyze chemical reactions compared to the bulk materials. However, scaling up the nanostructures remains complicated and limits the applications as industrial catalysis. Here, we demonstrate a facile method to fabricate a robust and versatile Cu nanostructure at a centimeter scale as an efficient photothermal catalytic reactor. By drop-casting the solution of Cu nanowires into a Teflon mold after solvent evaporation followed by annealing in the H2/Ar atmosphere, a Cu nanowire fabric possessing a network structure with a high density of porosity is formed. The Cu fabric exhibits a strong absorptance at the spectral range of 400–1200 nm owing to the interband transition, the surface plasmon resonances of Cu nanowires with their near-field coupling, and “light trapped effect” in the network structures. Exposure to 808 nm laser allows for the elevation of the temperature across the whole structure within 2 s and maintaining a stable temperature up to 250 °C for 2 h. A heterogeneous copper-catalyzed azide-alkyne cycloaddition reaction is performed using Cu nanowire fabric illuminated by an 808 nm laser. A repeatable yield of >90% with a reaction time of 4 h, an order of magnitude shorter than conventional copper catalysts at ambient temperature, is achieved suggesting the Cu nanowire fabric as a robust photothermal catalytic reactor.

Si nanowires/Cu nanowires bilayer fabric as a lithium ion capacitor anode with excellent performance

A light and binder-free bilayer fabric electrode composed of silicon nanowires and copper nanowires for lithium-ion capacitors (LICs) is reported. A lithium ion capacitor is proposed employing pre-lithiated silicon/copper nanowire fabric and activated carbon as the anode and the cathode, respectively. These LICs show remarkable performance with a specific capacitance of 156 F g−1 at 0.1 A g−1, which is approximately twice of that of activated carbon in electric double-layer capacitors (EDLCs), and still exhibit a fine specific capacitance of 68 F g−1 even at a high current density of 20 A g−1. At a low power density of 193 W kg−1, the Si/Cu fabric//AC LIC can achieve high energy density of 210 W h kg−1. As the power density is increased to 99 kW kg−1, the energy density still remains at 43 W h kg−1, showing the prominent rate performance.

Flexible Transparent and Free-Standing SiC Nanowires Fabric: Stretchable UV Absorber and Fast-Response UV-A Detector.

Transparent and flexible materials are desired for the construction of photoelectric multifunctional integrated devices and portable electronics. Herein, 2H-SiC nanowires are assembled into a flexible, transparent, self-standing nanowire fabric (FTS-NWsF). The as-synthesized ultralong nanowires form high-quality crystals with a few stacking faults. The optical transmission spectra reveal that FTS-NWsF absorbs most incident 200-400 nm light, but remains transparent to visible light. A polydimethylsiloxane (PDMS)-SiC fabric-PDMS sandwich film device exhibits stable electrical output even when repeatedly stretched by up to 50%. Unlike previous SiC nanowires in which stacking faults are prevalent, the transparent, stretchable SiC fabric shows considerable photoelectric activity and exhibits a rapid photoresponse (rise and decay time < 30 ms) to 340-400 nm light, covering most of the UV-A spectral region. These advances represent significant progress in the design of functional optoelectronic SiC nanowires and transparent and stretchable optoelectronic systems.

High-performance lithium-ion batteries with 1.5 μm thin copper nanowire foil as a current collector

Abstract Cu Foil, a thin sheet of Cu, is the common anode current collector in commercial lithium ion batteries (LIBs) which accounts for ∼ 10 wt% of the total cell weight. However, thickness reduction of LIB-based Cu foils below 6 μm has been limited by the incapability of conventional rolling annealing or electrodeposition process. We here report a new type of Cu foil, so called Cu nanowire foil (CuNW foil), for use as an LIB anode current collector. We fabricate Cu NW foils by rolling press Cu nanowire fabric to reduce the thickness down to ∼1.5 μm with an areal weight down to ∼1.2 mg cm−2 and a density approximately 96% to that of bulk Cu. The rough surface and porous structure of CuNW foil enable better wetting and adhering properties of graphite slurry on foil. In full cell examination, a cell of a areal capacity of 3 mAh cm−2 exhibits 83.6% capacity retention for 600 cycles at 0.6 C that meets the standard specification of most commercial LIBs. As a proof-of-concept of demonstration, we fabricate a 700 mA pouch-type battery implemented with graphite-Cu NWs foil anodes to serve as energy supply to operate electronic devices.

Variability in Nanoscale Fabrics

Emerging nanodevice-based architectures will be impacted by parameter variation in conjunction with high defect rates. Variations in key physical parameters are caused by manufacturing imprecision as well as fundamental atomic scale randomness. In this article, the impact of parameter variation on nanoscale computing fabrics is extensively studied through a novel integrated methodology across device, circuit and architectural levels. This integrated approach enables to study in detail the impact of physical parameter variation across all fabric layers. A final contribution of the article includes novel techniques to address this impact. The variability framework, while generic, is explored extensively on the Nanoscale Application Specific Integrated Circuits (NASICs) nanowire fabric. For variation of σ = 10 in key physical parameters, the on current is found to vary by up to 3.5X. Circuit-level delay shows up to 118% deviation from nominal. Monte Carlo simulations using an architectural simulator found 67% nanoprocessor chips to operate below nominal frequencies due to variation. New built-in variation mitigation and fault-tolerance schemes, leveraging redundancy, asymmetric delay paths and biased voting schemes, were developed and evaluated to mitigate these effects. They are shown to improve performance by up to 7.5X on a nanoscale processor design with variation, and improve performance in designs relying on redundancy for defect tolerance, without variation assumed. Techniques show up to 3.8X improvement in effective-yield performance products even at a high 12% defect rate. The suite of techniques provides a design space across key system-level metrics such as performance, yield and area.

Optical Properties of Silicon and Germanium Nanowire Fabric

The optical properties of free-standing nonwoven silicon (Si) and germanium (Ge) nanowire fabrics, including diffuse and specular reflectance, diffuse and direct transmittance, and absorptance spectra, were measured using an integrating sphere to account fully for all incident photons. Very thin, 50 μm thick, sheets with ∼90% void volume have extremely high optical densities. They are optically opaque across nearly all wavelengths from ultraviolet to near-infrared, and only minimal light penetrates when photon energies are below the band gap. The high optical density arises from a combination of scattering and absorption due to their high aspect ratio and narrow diameter as well as surface effects due to their very high surface area to volume ratio.

Silicon Nanowire Fabric as a Lithium Ion Battery Electrode Material

A nonwoven fabric with paperlike qualities composed of silicon nanowires is reported. The nanowires, made by the supercritical-fluid-liquid-solid process, are crystalline, range in diameter from 10 to 50 nm with an average length of >100 μm, and are coated with a thin chemisorbed polyphenylsilane shell. About 90% of the nanowire fabric volume is void space. Thermal annealing of the nanowire fabric in a reducing environment converts the polyphenylsilane coating to a carbonaceous layer that significantly increases the electrical conductivity of the material. This makes the nanowire fabric useful as a self-supporting, mechanically flexible, high-energy-storage anode material in a lithium ion battery. Anode capacities of more than 800 mA h g(-1) were achieved without the addition of conductive carbon or binder.

Transport selectivity of tribenuron‐methyl imprinted polymer nanowire membrane prepared using N,O‐bismethacryloyl ethanolamine as a functional crosslinking monomer

AbstractUsing tribenuron‐methyl as a template and N,O‐bismethacryloyl ethanolamine as a functional crosslinking monomer, a molecularly imprinted nanowire membrane was prepared over an anodic alumina oxide membrane. The nanowire fabric of the imprinted membrane was established with a scanning electron microscope and a transmission electron microscope. However, the nonimprinted particulate membrane is formed in the absence of a template. Scatchard analysis showed that an equal class of binding sites were formed in the imprinted nanowire membrane and the dissociation constant and the maximum number of these binding sites were estimated to be 1.44 × 10−5 M and 22.7 µmol/g, respectively. The permeation experiments throughout the imprinted membrane and the nonimprinted one were carried out in a solution containing the template and its competitive analogs. These results demonstrated that the molecularly imprinted nanowire membrane exhibited higher transport selectivity for the template tribenuron‐methyl than its analogs, chlorimuron‐ethyl, thifensulfuron‐methyl and N‐(4‐bromophenylcarbamoyl)‐5‐chloro‐1H‐benzo[d]imidazole‐2‐carboxamide. But the nonimprinted granular membrane had no permselectivity for the four substrates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010