Long-term electrically stable silver nanowire composite transparent electrode under high current density

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Silver nanowire (AgNW) network has been employed into many electronic devices as transparent electrode. However, the poor electrical stability under current shock has been seriously holding its practical application, and we still lack a long-term electrically stable AgNW system to study the underlying fundamentals of electrical failure. In this work, the electrical stability performance and failure mechanism of chitosan–ascorbic acid (Chi-AsA)/AgNW composite under current stress were thoroughly studied. The composite electrode maintained stable above 24,000 h under high current density of 100 mA cm−1. The main failure in AgNW composite is found to be a wave break perpendicular to the current instead of traditional uniform degradation across the entire AgNW networks. More interestingly, the AgNWs in failed composite electrode maintained their original smooth morphology excepting the crack region, while the AgNWs in pristine networks degraded to nanoparticles or became disconnected everywhere. The patterned AgNW composite in microscale exhibits long lifetime in resisting current stress as well. The effect of over-coating location, electrical stress, temperature, and over-coating materials on the electrical stability were studied. The over-coating layer of Chi-AsA is proven to suppress the silver atoms from electromigration, reduce the concentrated Joule heating at junctions, and inhibit the corrosion. The Chi-AsA/AgNW composite enables electrically stable transparent conductor for long-serving optoelectronics, and the mechanism investigation deepens the comprehension of preparing electrically stable AgNW system.