Highly transparent graphene oxide composited TiO2 thin film as efficient photoanode for dye-sensitized solar cells

Abstract

Here we report the fabrication of highly transparent graphene oxide (GO) reinforced TiO2 nanocomposite thin film and demonstrate that it enhances the power conversion efficiency of dye-sensitized solar cells (DSSC) when used as photoanode. TiO2-GO nanocomposite thin films with varying GO concentrations are deposited on top of the fluorine doped tin oxide (FTO) coated glass substrate by easy, cost-effective sol-gel spin coating technique. Microstructural and optical characterizations confirm the formation of highly transparent, uniform nanocomposite thin films comprised of rutile phase of TiO2 nanoparticles. The estimated optical band gap of pristine TiO2 is ~3.34 eV which decreased slightly with GO concentrations. The nanocomposite films are used as photoanode of a basic DSSC structure which has been fabricated using commercially available N3 dye as photosensitizers, conventional iodine solution (I-/IM3+) as electrolyte and FTO-coated glass as counter electrode. The current-voltage characteristics of DSSC measured under illumination of 1 SUN AM1.5 solar spectrum show significant enhancement of short circuit current density (Jsc) and power conversion efficiency (η) with GO concentration in TiO2 photoanode which is attributed to the less recombination of photogenerated charge carriers and better transport facilitated by conduction GO network.