Low-temperature luminescence of different TiO2 modifications

The results of luminescence spectra investigations of titanium dioxide two polydisperse modifications (anatase and rutile) in 5-180 K temperature range are presented. Luminescence spectra of anatase have two broad bands at 400 nm (phosphorescence) and 545 nm (fluorescence) with life-times of 1 s and less than 10−4 s, correspondingly. Phosphorescence process for polydisperse anatase has been observed for the first time. Temperature dependences of luminescence spectral parameters are described. Rutile luminescence spectra consist of only phosphorescence broad band at 412 nm. Different rates of luminescence intensity drop for coarse-dispersed (20 μm) and tiny-dispersed (200 nm) rutile are explained by the different influence of the particle surface in these samples. The analysis of luminescence band peak positions for rutile particles with different sizes reveals the appearance of quantum-sized effects.