Abstract
Silver nanowire (AgNW) network has been employed to many electronic devices as transparent electrode. However, the poor electrical stability under current has been seriously holding its practical application, and we still lack long-term electrically stable AgNW system to study the underlying fundamental of electrical failure. In this work, the electrical performance and failure mechanism of chitosan-ascorbic acid (Chi-AsA)/AgNW composite under current stress were thoroughly studied. The composite electrode maintained stability above 24000 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 rather than traditional uniform degradation across AgNW networks. More interestingly, the AgNWs in failed composite electrode kept their original smooth morphology excepting the crack area, while the AgNWs in pristine networks degraded to nanoparticles or became disconnected everywhere. The patterned AgNW composite in microscale exhibits similar long lifetime in resisting current stress as the bulk composite film. The effect of over-coating position, 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 migration, reduce the concentrated Joule heating at junctions, and inhibit the corrosion. The Chi-AsA/AgNW composite enables electrically stable transparent conductor for next-generation optoelectronics, and the mechanism investigation may provide effective means of preparing electrically stable AgNW systems.
Long-term electrically stable silver nanowire composite transparent electrode under high current density
