<scp>UV</scp>‐aided graphene oxide reduction by <scp>TiO₂</scp> towards <scp>TiO₂</scp>/reduced graphene oxide composites for dye‐sensitized solar cells

Abstract

Summary Electron transport layer is one of the important layer in the dye‐sensitized solar cells (DSSCs) which is responsible for the transport of photo‐generated electrons by the dye to the outer circuit. TiO 2 has been widely used as electron transport material in DSSCs. However, improving the electrical conductivity of TiO 2 without sacrificing the surface area is one of the important strategies to improve the efficiency of the DSSCs. Here graphene oxide (GO) is added as an additive into the TiO 2 network towards the preparation of TiO 2 /reduced graphene oxide (RGO) composites by UV assisted photocatalytic reduction method. The RGO/TiO 2 composites with different compositions of RGO were characterized and the performance of DSSCs using the prepared material as photoanode was studied. Furthermore, through the D and G band Raman peaks, the reduction of GO to RGO was confirmed. The optical properties of the prepared material were analyzed using UV‐visible spectroscopy and photoluminescence analysis, respectively. The carrier lifetime of the TiO 2 and TiO 2 /RGO composites was studied using time resolved photoluminescence studies. The high‐resolution transmission electron microscope images of prepared TiO 2 /RGO composites were found to have sheet‐like structure surrounding the near spherical nanoparticles, which could be attributed to that of RGO and TiO 2 , respectively. The binding energy states of the prepared material were studied using X‐ray photoelectron spectroscopy (XPS) spectra. The incorporation of RGO in TiO 2 was found to improve the Brunauer–Emmett–Teller (BET) surface area of TiO 2 and distribution of pores in TiO 2 and TiO 2 /RGO composites was found to be uniform. The DSSCs were fabricated using the prepared TiO 2 and TiO 2 /RGO composites as photoanodes and their power conversion efficiencies were analyzed.