Effect of graphene oxide on microstructure and optical properties of TiO₂ thin film

Abstract

GO/TiO₂ thin films have been synthesized from titanium (IV) isopropoxide (TTIP) by a sol-gel method. The films were deposited onto a glass substrate using spin coating deposition technique then were subjected to annealed process at 350 °C. The different amount of graphene oxide (GO) was added into the parent solution of sol in order to investigate the microstructure, topography, optical band gap and photocatalytic activity of the thin films. The prepared thin films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), UV-VIS spectrophotometry and degradation of methylene blue (MB). AFM images reveal a rougher surface of GO/TiO₂ thin film than bare TiO₂ thin film due to GO particles. Moreover, the SEM images showed the formation of semispherical microstructure of bare TiO₂ changes to some larger combined molecules with GO addition. The UV–Vis spectrophotometer results show that with optical direct energy gap decreases from 3.30 to 3.18 eV after GO addition due to the effect of high surface roughness and bigger grain size. Furthermore, the optical results also indicated that GO improved the optical properties of TiO₂ in the visible range region.