Ag Nanowire-Based Stretchable Electrodes and Wearable Sensor Arrays

Attributed to excellent mechanical compatibility with the human body and thus favorable comfortability and good integrability, stretchable conductors and functional conductive patterns have been one of the most important components in wearable electronic devices. However, due to poor compatibility between stretchability and conductivity in most material system, the simple, fast, and low-cost fabrication of a stretchable conductor, especially conductive patterns, has been a problem to address in this field. In this paper, we propose a flexible and robust laser ablation method in combination with a two-step film transfer process for the fabrication of stretchable silver nanowire (AgNW)-based conductive patterns. In this method, three critical steps were involved for the optimized properties. First, a simple one-pot solvothermal method was developed for scalable synthesis of high-quality AgNWs; second, a reliable film transfer method was proposed to ensure complete replication of the properties of the AgNW film; third, a digital laser ablation technique was employed for the selective removal of the AgNW layer. Finally, stretchable transparent conductive electrodes, circuits, and functional patterns were fabricated. As a proof-of-concept demonstration, a wearable sensor and multipixel capacitive sensor arrays were prepared and showed good and reliable performance under various deformations, indicating the proposed method is available for the fabrication of various stretchable conductive patterns

Graphene based functional devices: A short review

Graphene is an ideal 2D material system bridging electronic and photonic devices. It also breaks the fundamental speed and size limits by electronics and photonics, respectively. Graphene offers multiple functions of signal transmission, emission, modulation, and detection in a broad band, high speed, compact size, and low loss. Here, we have a brief view of graphene based functional devices at microwave, terahertz, and optical frequencies. Their fundamental physics and computational models were discussed as well

Flexible Transparent PES/Silver Nanowires/PET Sandwich-Structured Film for High-Efficiency Electromagnetic Interference Shielding

We have developed a kind of high-yield synthesis strategy for silver nanowires by a two-step injection polyol method. Silver nanowires and polyethylene oxide (PEO) (<i>M</i>_w = 900 000) were prepared in a homogeneous-coating ink. Wet composite films with different thicknesses were fabricated on a PET substrate by drawn-down rod-coating technology. Silver nanowires on PET substrates present a homogeneous distribution under the assistance of PEO. Then PEO was thermally removed in situ at a relatively low temperature attributed to its special thermal behavior under atmospheric conditions. As-prepared metallic nanowire films on PET substrates show excellent stability and a good combination of conductivity and light transmission. A layer of transparent poly­(ethersulfones) (PESs) was further coated on silver nanowire networks by the same coating method to prevent the shedding and corrosion of silver nanowires. Sandwich-structured flexible transparent films were obtained and displayed excellent electromagnetic interference (EMI) shielding effectiveness

A Robust Aluminum Metal-Organic Framework with Temperature-Induced Breathing Effect

A robust, yet flexible, Al-based metal-organic framework (MOF), Al2(OH)2(bpydc)·0.5H2O (1np), is synthesized via a hydrothermal strategy utilizing 2,2′-bipyridine-5,5′-dicarboxylate (bpydc2–) as the organic ligand. The structure of 1np is built from infinite trans chains of corner-sharing AlO4(OH)2 octahedra interconnected by bpydc2– ligands, forming a three-dimensional framework. 1np is robust, because of its superior thermal, hydrothermal, and chemical stability. The flexibility of 1np is reflected in the activation by the removal of unreacted H2bpydc molecules and/or occluded solvent molecules, followed by degassing at 250 °C, leading to the large pore form (1lp) of the title compound. A reversible structural change from 1lp to 1np is achieved via the hydration in water at 200 °C. The unusual combination of rigidity and flexibility enables precise control and fixation of the swelling magnitude in this MOF material

Plasmonic Light Illumination Creates a Channel to Achieve Fast Degradation of Ti3C2Tx Nanosheets

Two-dimensional (2D) material-controllable degradation under light radiation is crucial for their photonics and medical-related applications, which are yet to be investigated. In this paper, we first report the laser illumination method to regulate the degradation rate of Ti3C2Tx nanosheets in aqueous solution. Comprehensive characterization of intermediates and final products confirmed that plasmonic laser promoting the oxidation was strikingly different from heating the aqueous solution homogeneously. Laser illumination would nearly 10 times accelerate the degradation of Ti3C2Tx nanosheets in initial stage and create many smaller-sized oxidized products in a short time. Laser-induced fast degradation was principally ascribed to surface plasmonic resonance effect of Ti3C2Tx nanosheets. The degradation ability of such illumination could be controlled either by tuning the excitation wavelength or changing the excitation power. Furthermore, the laser- or thermal-induced degradation could be retarded by surface protection of Ti3C2Tx nanosheets. Our results suggest that plasmonic electron excitation of Ti3C2Tx nanosheets could build a new reaction channel and lead to the fast oxidation of nanosheets in aqueous solution, potentially enabling a series of water-based applications

Electronic Structure Modulation of Unconventional Phase Metal Nanomaterials for Highly Selective Carbon Dioxide Electroreduction

The electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) has been considered as a promising approach to convert atmospheric CO2 to value-added chemicals to promote carbon neutrality. However, developing electrocatalysts with superior activity and high selectivity toward individual products remains a great challenge. Herein we report the electronic structure modulation of unconventional phase metal nanomaterials to achieve highly efficient CO2 electroreduction. It has been found that growing cerium oxide (CeOx) nanostructures on 4H/face-centered cubic (fcc) gold (Au) nanorods can significantly enhance their catalytic activity and selectivity toward the electrochemical conversion of CO2 to carbon monoxide. X-ray analysis indicates the electronic structure change of 4H/fcc Au nanorods after CeOx overgrowth. In-situ attenuated total reflection infrared spectroscopy measurements reveal that the HCO3– concentration near the surface of Au-CeOx heteronanostructures is much higher than that of Au nanorods, facilitating the CO2 reduction process. Density functional theory calculations suggest the activation effect of CeOx on the 4H/fcc Au nanorod surface for the electrocatalytic CO2RR. The synergy between 4H/fcc Au and CeOx promotes the formation of carboxyl (*COOH) species and thus boosts the electrocatalytic CO2RR performance. This work highlights the importance of rational electronic structure regulation of unusual phase nanomaterials toward the electrocatalytic conversion of small molecules