Near-infrared photoluminescence in titania:: Evidence for phonon-replica effect

The photoluminescence of rutile and anatase TiO2 has been investigated in the range of 360-890 nm at several temperatures. An unexpected intense near-infrared (1.53 eV) photoluminescence band was recorded for both phases. At low temperatures, the resulting bands form a substructure of equally spaced peaks irrespective of the phase. The spectra were interpreted in the framework of the single-configuration-coordinate model as the phonon-replica effect, originating from ionization of oxygen vacancies. (C) 2003 American Institute of Physics.