Synthesis and luminescence enhancement of Eu³⁺, Sm³⁺ co-doped Li_1.11Ta_0.89Ti_0.11O₃ phosphor

Graphical abstract: Enhancement of red emission intensity and internal- and external-quantum efficiencies by co-doping of Eu³⁺ and Sm³⁺ ion in Li_1.11Ta_0.89Ti_0.11O₃ phosphor. - Abstract: Phosphors based on the Li_1+xTa_1−xTi_xO₃ solid solutions (0.05 ≤ x ≤ 0.25) as host materials were investigated. The optimal composition of the host for red-light emitting phosphor was found to be Li_1.11Ta_0.89Ti_0.11O₃ (x = 0.11) when activated with Eu³⁺. In this work, in order to further enhance the emission intensity, a series of Eu³⁺- and Sm³⁺-doped Li_1.11Ta_0.89Ti_0.11O₃ phosphors was synthesized by solid-state reaction. The phosphor doped with 2.5 wt% Eu₂O₃ and 0.1 wt% Sm₂O₃ showed the highly efficient red-light emission upon excitation at 399 nm, with the internal quantum efficiency being 98%. Its PL intensity was ca. 1.4 times higher than that of the 2.5 wt% Eu³⁺-doped Li_1.11Ta_0.89Ti_0.11O₃ phosphor, indicating that the small amount of Sm³⁺ acted as an effective sensitizer