Solution‐Processed and Transparent Graphene Oxide/TiO x Gas Barrier via an Interfacial Photocatalytic Reduction

A cost‐effective, flexible, and transparent gas barrier has been a main pursuit of research into plastics electronics. However, it is difficult to realize a high‐performance gas barrier on a plastic substrate via a solution process at low temperature. Here, by introducing an interfacial photocatalytic reduction between TiO x and graphene oxide (GO) films, a solution‐processed and transparent gas barrier film is demonstrated using reduced GO (rGO)/TiO x . A dramatic photochemical reduction of GO occurs at the interface between TiO x and the GO film under ultraviolet irradiation, which allows the fabrication of dense and uniform gas barrier films via a solution process at temperatures below 100 °C. In addition, the closely packed structure in the rGO film results in a decreased water vapor transmission rate (WVTR) of 0.37 g m −2 day −1 even with a thin rGO (<13 nm)/TiO x (7 nm) film, leading to a high transmittance of over 80% in the visible range.