Direct growth of few-layer graphene films on SiO2 substrates and their photovoltaic applications

We first demonstrate the use of few layer graphene films directly grown on SiO2 substrates obtained by ambient pressure chemical vapor deposition (APCVD) as counter electrodes in dye-sensitized solar cells (DSSCs). The layer number and crystal size of graphene films can be tuned by changing growth temperature, growth time and gas flow ratio (CH4 : H-2). The continuous graphene films exhibit extremely excellent electrical transport properties with a sheet resistance of down to 63.0 Omega sq(-1) and extremely high mobility of up to 201.4 cm(2) v(-1) s(-1). The highly conductive graphene films as counter electrodes of DSSCs achieve a photovoltaic efficiency of 4.25%, which is comparable to the DSSC efficiency (4.32%) based on FTO counter electrodes. Our work indicates the great potential of CVD graphene films directly grown on dielectric substrates for photovoltaic and electronic applications.