Photoluminescence study of anatase and rutile structures of Fe-doped TiO2 nanoparticles at different dopant concentrations

In this work, dependence of the surface and lattice defects of Fe-doped TiO2 at different iron concentrations and annealing temperatures was monitored by utilizing the photoluminescence (PL) spectroscopy. To achieve the maximum spectral resolution, PL spectroscopy was performed in vacuum and at different temperature of 25–300 K. It has been found that the photoluminescene properties were significantly influenced by different crystalline structure. The PL spectrum of the rutile 1% and 5% Fe:TiO2 anatase show similar PL behavior while the emission intensity of the rutile sample was lower than the anatase. This result, which can be explained by the presence of iron ions at the surface for the anatase and the increased oxygen vacancies due to the diffusion of iron into the lattice in rutile, as a result of annealing at high temperature proposes the rutile phase for the applications of environmental photocatalysis.