Structural, optical properties and photocatalytic activity of Fe3+ doped TiO2 thin films deposited by sol-gel spin coating

Nanocrystalline TiO2:Fe3+ films were deposited using a simple spin coating technique. The effect of Fe3+ on spectroscopic features and photocatalytic activity of films were studied using X-ray diffractometer (XRD), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), high-resolution transmission electron microscope (HR-TEM), Raman spectrometer, UV-Vis and fluorescence spectrophotometer. The XRD of all the TiO2:Fe3+ films exhibits a decrease in the crystallite size with an increase in Fe3+ concentration. The Fe3+ doped TiO2 nanocrystals exhibited a high specific surface area. The HR-TEM images of 1% and 7% Fe doped TiO2 thin films confirmed the average particle size is about 14 and 8 nm respectively. The Raman modes of vibrations present in the TiO2:Fe3+ films also confirms the formation of the anatase phase. The optical bandgap energy of titania decreases from 3.32 to 2.57 eV. The luminescent emission intensity of TiO2:Fe3+ films decreased compare to pure titania film. Moreover, the photocatalytic activity (PCA) of TiO2:x%Fe3+ (x = 0, 1, 3, 5, 7 and 10) catalysts were determined by the decomposition of methylene blue (MB) under irradiation of visible light. The observed results revealed that the optimized Fe3+ doped TiO2 film displayed high PCA. The enhancement of PCA of the films is due to the effect of Fe doping.