Investigation on the surface state of TiO2 ultrafine particles by luminescence

The surface states of TiO2 ultrafine particles (UFP) are characterized by luminescence spectra and UV-absorption spectra. In order to confirm whether the emission at 475 nm originates from the surface state, the as-prepared TiO2 UFP are plasma-treated. The results indicate that surface states related to the TiOH and TiOC2H5 groups play an important role in the emission and UV-absorption of TiO2UFP. Both quantum confinement and dielectric confinement effects have been used for discussing the emission and UV-absorption properties of TiO2 UFP. (C) 1999 Academic Press.