Time-resolved study of photoluminescence in anatase TiO2

The luminescence of self-trapped excitons (STE) in anatase phase of TiO2 has been studied by time-resolved spectroscopy. It is found that the decay curves of the luminescence band consist of two components obeying exponential and power-law decay. Both components have the same spectral shape but the intensity of the power-law part is suppressed compared to that of the exponential part with increasing the excitation density. Thc se facts suggest that two different processes exist for the formation of STE. (C) 2000 Elsevier Science B.V. All rights reserved.