Effect of metal ions doping on structural, optical properties and photocatalytic activity of anatase TiO2 thin films

Abstract

The metal ion‐doped (Fe3+, Co2+, Ni2+ and Ag+) TiO2 nanocrystalline thin films were spin‐coated on glass substrates. The grazing incidence X‐ray diffractometer (GIXRD), SEM, energy‐dispersive X‐ray Spectroscopy (EDX), Raman, UV–VIS and a fluorescence spectrometer were employed to study the structural, compositional and optical properties of metal‐doped TiO2 films. As revealed by GIXRD, all the metal‐doped TiO2 thin films were found to anatase tetragonal crystal structure. The deposited films were optimized using annealing temperature (550°C) to get high‐quality crystalline films with the anatase phase. The thin films with the specific surface area of Fe‐, Co‐, Ni‐ and Ag‐doped anatase TiO2 nanocrystals are 152.18, 88.25 96.68 and 178.38 m2/g, respectively, which has been calculated by GIXRD results. Optical transmittance spectra were used to determine the thickness, band gap energy and refractive index of metal‐doped TiO2 thin films. The characteristic vibrational Raman modes also revealed that the films were found to be anatase phase. The intensity of luminescence emission decreases with the doping of metal ions. Metal‐doped TiO2 films exhibit strong photocatalytic performance than undoped TiO2 films. The degradation efficiencies typically increase with the different dopants for the visible‐light degradation of methylene blue (MB) and methyl orange (MO). Moreover, the photocatalytic activity (PCA) of silver ion‐doped titania thin film is found to be better than that of Fe3+‐, Co2+‐, and Ni2+‐doped TiO2 films.