Improved Stability of Copper Nanowires with Solution-Grown NiO Shells as Protective Coating

The fast degradation of copper in ambient conditions hinders the practical application of copper nanowires (Cu NWs) in flexible electronics. Here, we describe a simple yet effective solution method for growing NiO shells on the surface of Cu NWs, which enables the protection of the Cu NW network against oxidation without degrading the optical and electrical properties. The corresponding values (for example, before coating: 13.6 Ω/sq at 84.4%, after coating: 14.9 Ω/sq at 84.8%) show that the deposition of NiO shell enables the preservation of high transparency and conductivity of Cu. In contrast to the massive degradation of Cu NW networks including a significant reduction in conductivity in a range of harsh environments (strong oxidation, high temperature, heat and humidity conditions), the Cu NW@NiO networks can survive structurally and maintain conductivity. Finally, a flexible alternating current electroluminescent device employing the Cu NW@NiO networks as the transparent electrodes is realized to demonstrate the availability of Cu NW@NiO networks.