Influence of annealing atmosphere on the structural phase changes and optical properties of TiO 2 nanoparticles

In the present work, structural and optical behaviour of sol-gel synthesized TiO 2 and Nitrogen doped TiO 2 (N-doped TiO 2 ) nanoparticles calcined under air and vacuum atmosphere have been analysed. N-doped TiO 2 samples were synthesized by adding ammonia as nitrogen source and as reducing agent. The molar concentration of Ammonia was fixed at 1 M and 2 M respectively. The incorporation of nitrogen into the TiO 2 samples was verified using X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) was used to examine the structural characteristics of air and vacuum-annealed samples, and Scherrer equation was used to determine the average crystallite size. Raman analysis was carried out to understand all the major modes of vibration in the annealed samples. UV-visible spectroscopy was carried to analyse the effect of different atmospheres on the band gap of the samples. Photoluminescence studies were used to understand the presence of defect states in the sample.