Highly enhanced photoluminescence of SrTiO3:Pr by substitution of (Li0.5, La0.5) pair for Sr

Photoluminescence (PL) of SrTiO3–(Li0.5La0.5)TiO3:Pr system was investigated. This system was characterized by a very intense red emission at 611 nm corresponding to the 1D2→3H4 inner transition of Pr3+ ions. A weak PL intensity of SrTiO3:Pr was remarkably increased when the Sr atom was replaced by the (Li, La) pair. Through the elemental analysis for the Li atom, the dependence of PL intensity on the composition and heating temperature is correlated with the amount of defect sites for the Li atoms. Based on the experimental data, it is proposed that the substitution of the (Li, La) pair for Sr of SrTiO3 likely produces the holes trapped near Li+. The increased recombination probability of electrons and trapped holes would then cause the highly enhanced emission intensity of Pr3+ by the resultant energy transfer.