Study intra-4f transitions of Sm³⁺ ions under direct photoexcitation in TiO₂

A systematic study of photoluminescence transitions of samarium ion (Sm³⁺) incorporated in titanium dioxide (TiO₂) powder with anatase structure has been performed. Perceptible changes of luminescence under direct excitation as compared with indirect excitation of Sm³⁺ in titanium dioxide (TiO₂:Sm³⁺) have been detected. Measurements of photoluminescence excitation spectra for all detected radiative transition of Sm³⁺ were accomplished. The values of asymmetry ratio were calculated for different excitation wavelengths. The dependence of luminescent intensity on Sm³⁺ doping concentration in TiO₂ host was studied under direct and indirect excitation. Thus, evidences of the existence of the several Sm³⁺ sites in anatase TiO₂ have been presented in this work. (paper)