Ultrathin-shell epitaxial Ag@Au core-shell nanowires for high-performance and chemically-stable electronic, optical, and mechanical devices

Abstract

Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.

Customizable Stretchable Transparent Electrodes Based on AgNW/CNT Hybrids via Tailoring Sizes of Building Blocks

“…This should arise from the partial removal of the protective PVP layer on the surfaces of AgNWs during the welding, which accelerates the oxidation of Ag atoms. To address this issue, post-processing protection approaches such as developing alternative protective layers or synthesizing core–shell structures − would be necessary for practical applications of such STEs.…”

Lab‐on‐a‐Contact Lens: Recent Advances and Future Opportunities in Diagnostics and Therapeutics

“…Surface-enhanced Raman scattering (SERS) has also contributed to the SCL advances. [189][190][191] For example, Lee et al constructed a multi-layered structure which could detect glucose levels through SERS. On this SCL, a layer of protective film was embedded with AgNWs.…”

A Breathable, Passive‐Cooling, Non‐Inflammatory, and Biodegradable Aerogel Electronic Skin for Wearable Physical‐Electrophysiological‐Chemical Analysis

“…To date, various E-skins have been reported for unobtrusive monitoring of single or multiple physical/physiological parameters, including biopotentials (i.e., electrocardiogram, ECG; electroencephalogram, EEG; or electromyography, EMG), body temperature, human motion, skin hydration as well as a library of metabolic markers (such as glucose, insulin, lactate, and cortisol). [15][16][17][18][19][20][21][22][23] However, most E-skins are limited to conventional elastomeric substrates (e.g., polydimethylsiloxane, PDMS; [18] polyimide; [24] polyethylene terephthalate; [25] and Ecoflex [26] ) which suffer from one or more drawbacks, including mechanical mismatch, poor biocompatibility, and low permeability. Such limitations prevent sweat evaporation off the skin and limit the emission of volatile organic components (VOCs), which lead to skin irritation and inflammation.…”