Mid-infrared absorption of trapped electrons in titanium(iv) oxide particles using a photoacoustic FTIR technique†
Abstract
Mid-infrared absorption of titanium(IV) oxide (TiO2) under ultraviolet (UV) irradiation was studied by Fourier transform infrared spectroscopy using a photoacoustic (PA) technique. UV irradiation induced an upward shift of the PA spectra, which is due to the trivalent titanium (Ti3+) species produced by electron accumulation. The PA spectra under UV irradiation mainly depend on the crystal structure, indicating that the energy levels of Ti3+ are largely determined by crystal structures.