Zinc Oxide-Encapsulated Copper Nanowires for Stable Transparent Conductors

Cu nanowire (NW)-based transparent conductors are considered to be highly promising constituents of next-generation flexible transparent electronics. However, the fast oxidation of copper under ambient conditions hinders the use of Cu NWs. Herein, we demonstrate a low-cost and scalable approach for preparing a ZnO shell on the surface of Cu NWs under ambient conditions. The covered ZnO shells enhance the oxidative stability of Cu NWs. The optical and electrical properties of ZnO@Cu NWs remain similar to the original performance of the Cu NWs (for example, before encapsulating: 13.5 Ω/sq. at 84.3%, after encapsulating: 19.2 Ω/sq. at 86.7%), which indicates that encapsulation with a ZnO shell enables the preservation of the transparency and conductivity of Cu NW networks. More importantly, the ZnO@Cu NWs exhibit excellent stability in terms of long-term storage, hot/humid environments, and strong oxidizing atmosphere/solution.