Hybrid transparent conductive film on flexible glass formed by hot-pressing graphene on a silver nanowire mesh.

Abstract

Polycrystalline graphene and metallic nanowires (NWs) have been proposed to replace indium tin oxide (ITO), the most widely used transparent electrode (TE) film on the market. However, the trade-off between optical transparency (Topt) and electrical sheet resistance (Rs) of these materials taken alone makes them difficult to compete with ITO. In this paper, we show that, by hot-press transfer of graphene monolayer on Ag NWs, the resulting combined structure benefits from the synergy of the two materials, giving a Topt-Rs trade-off better than that expected by simply adding the single material contributions Ag NWs bridge any interruption in transferred graphene, while graphene lowers the contact resistance among neighboring NWs and provides local conductivity in the uncovered regions in-between NWs. The hot-pressing not only allows graphene transfer but also compacts the NWs joints, thus reducing contact resistance. The dependence on the initial NW concentration of the effects produced by the hot press process on its own and the graphene transfer using hot press was investigated and indicates that a low concentration is more suitable for the proposed geometry. A TE film with Topt of 90% and Rs of 14 Ω/sq is demonstrated, also on a flexible glass substrate about 140 μm thick, a very attractive platform for efficient flexible electronic and photonic devices.