Enhanced Electrical Properties of Reduced Graphene Oxide Multi layer Films by In-Situ Insertion of a TiO2 Layer

Abstract

Wrinkle-free reduced graphene oxide (rGO)TiO2 hybrid multilayer films were directly fabricated using an rGO solution stabilized by a TiO2 precursor sol applied over a large area by an air spraying method without the use of additional reduction processes. In-situ insertion of the TiO2 layer between rGO sheets dramatically increased the conductivity and carrier mobility despite the insulating properties of amorphous TiO2. The TiO2 situated between rGO sheets also Induced significant hole doping. Electrical hysteresis caused by adsorbed water molecules and residual oxidative moieties In the rGO nanosheets vanished due to TiO2-assisted screening of charged impurities. These effects decreased the thermal carrier activation energy and increased the density of states at the Fermi level. Ambipolar transport properties were converted into unipolar-like hole transport characteristics by extensive hole doping in the TiO2 layer.