Investigation into the failure mechanism of silver nanowire network film under electrical stress

摘要

Silver nanowire (AgNW) network film exhibits good transparency, conductivity and flexibility, which has been widely studied as the transparent electrode in electronics. The weak stability of AgNW film under electrical stress may bring about high risk of device failure, but insufficient studies have been devoted to the electrical failure mechanism of AgNW film. In this work, we investigated the failure mechanism of AgNW network film under electrical stress, and discussed the relationship between electrical stability and electrical type, current density, temperature and humidity, respectively. AgNW film exhibits much better stability under AC stress than DC stress, and electromigration has significant effect on the failure of AgNW network under DC stress. The synergistic effect of short-range electromigration and Joule heating under DC stress results in the failure mode of narrow break line in the film perpendicular to the current flow. The location of break line moves from middle area to anode side with decreased current density, attributed to the change of dominant mechanism from thermal fusing to electromigration. The electrical lifetime demonstrates exponential function relationship with temperature, and the activation energy is calculated to be 0.53 eV below 136 °C. In addition, electrochemical migration is confirmed in AgNW network failure under high humidity environment. The understanding of the electrical failure mechanism of AgNW network in multiple conditions provides reference for evaluating and improving the applied reliability of AgNW film.