Photoluminescence and energy transfer of terbium doped titania film

Strong visible luminescence of Tb3+ions due to intra-4f shell transitions are obtained from Tb3+-doped titania (TiO2) films fabricated by sol-gel method. Based on the overlap of excitation band of Tb3+-doped TiO2 and absorption band of undoped TiO2, we propose an energy transfer mechanism from TiO2 host to Tb3+ions. Photoluminescence (PL) intensity is found to have a well matching relation with the doping concentration of Tb3+ ions. Concentration quenching of PL occurs when Tb3+ concentration exceeds a certain value (9.5 mol%). Luminescence intensity is improved obviously after co-doped with Ce3+ ions because of the sensitization effect of Ce3+ ions and the dispersion of Tb3+ ions in TiO2 system.