The structural, optical and photocatalytic properties of the TiO2 thin films

Abstract

Nanostructured TiO2 thin films were prepared by sol-gel method on the glass substrates and annealed at various temperatures in air atmosphere. The structural and optical properties have been studied as a function of the annealing temperature. XRD diffraction spectra reveals that the anatase phase transformed into orthorhombic brookite phase when annealing at the temperature of 600 °C. SEM and AFM images indicate that grain size and average roughness of the films were increased with the increasing of annealing temperature. In contrast, the optical band gap was decreased with increasing of the annealing temperature. Moreover, anatase phase TiO2 thin film has the best photocatalytic activity compared to amorphous and brookite TiO2 thin films and kept the high degradation rate in all cycling experiments.