Fabrication of highly transparent and conductive graphene thin films using hybridization with metal nanowires

Abstract

Graphene is one of the most promising nanomaterials used in the fabrication of flexible transparent conductive films owing to its high charge carrier mobility of up to 200,000 cm2/Vs, its flexibility, and its high optical transparency. Despite intensive research efforts in this field, the conductivities of graphene films reported thus far remain very low, and the films are not yet suitable for replacing the transparent conducting films currently implemented in optoelectronic flexible foldable devices. In this study, the fabrication of highly efficient transparent conducting graphene films is demonstrated by hybridization with metal nanowires. Chemical vapor deposition (CVD) grown graphene films are hybridized with silver nanowires (AgNWs) below percolation threshold to improve their electrical properties and understand the role of AgNWs in polydomain graphene. Combination of chemical doping and hybridization with silver nanowires is performed to enhance significantly the conductivity of graphene films. Solution-processable reduced graphene oxide (RGO) films are hybridized with low density AgNWs to reduce the sheet resistance of RGO films without a little change of transmittance. Firstly, we demonstrate that the presence of a few one-dimensional (1D) metallic nanowires can significantly enhance the electrical conductance of a graphene film. Studies of the film’s optical birefringence, field-effect transistor (FET) transport properties, Raman spectra, and electrical resistance clearly showed that the improvements in the graphene film electrical conductance properties upon the addition of silver nanowires (AgNWs) did not result from the chemical doping properties of the AgNWs, but rather due to the connections among the domains in the graphene film facilitated by the AgNWs. The electrical conductance of the polydomain graphene was dramatically enhanced by more than 30% in the presence of the AgNWs. Thermal annealing of the graphene?AgNW hybrid films further enhan...