High aspect ratio copper nanowires and copper nanoparticles decorated by reduced graphene oxide for flexible transparent conductive electrodes

Copper nanowires (CuNWs) have been widely used in flexible electronics and optoelectronic devices. However, the large contact resistance and poor stability limit their practical applications in optoelectronic devices. Herein, the high aspect ratio CuNWs and uniform ultra-small copper nanoparticles (CuNPs) were grown in-situ on the reduced graphene oxide (rGO) to form copper/reduced graphene oxide (Cu/rGO) nanocomposite by a one-step hydrothermal method. Graphene oxide, which converted to rGO in the synthesis, played an essential role in forming the high aspect ratio CuNWs (L/D ≈ 1666) and the dispersed ultra-small CuNPs (diameter ≈ 2 nm). The photoelectric properties of rGO/Cu/rGO flexible transparent conductive electrodes, assembled by Cu/rGO nanocomposite and outer layer rGO, reduced from graphene oxide by sodium borohydride solution, can be extended over 65 h at 60 °C in air. The high aspect ratio CuNWs and ultra-small CuNPs decorated by rGO resulted in a good bending resistance. This approach is anticipated as an effective strategy to solve problems with oxidation of CuNWs and promote their various applications in flexible optoelectronic devices.