Enhanced photoluminescence of a novel red-emitting phosphor of CaLaGaO4:Eu3+ by lithium ion doping

CaLaGaO₄:Eu³⁺ and Li ⁺ -doped CaLaGaO₄:30 %Eu³⁺ series phosphors were synthesized via high-temperature solid-state reactions. The results show that these phosphors can be efficiently excited by near-ultraviolet light at 392 nm and emit intense red light at 609 nm. The red emission at 609 nm corresponds to the hypersensitive electric dipole transition of Eu³⁺ (⁵D₀ → ⁷F₂). Upon reaching 30 % Eu³⁺ doping concentration, a distinct concentration quenching phenomenon emerges. Subsequent Li⁺ co-doping investigation demonstrates that incorporating 0.5 % Li⁺ induces remarkable luminescence enhancement: (1) The room-temperature fluorescence intensity exhibits 1.56-fold augmentation compared to Li⁺-free counterparts; (2) The absolute quantum yield (QY) increases from 11.3 % to 21.6 %, representing 91.2 % relative improvement; (3) Thermal stability characterization reveals 81.9 % intensity retention at 498 K (vs. 75.0 % in undoped system), corresponding to 9.2 % relative enhancement in thermal endurance. These findings suggest that the introduction of Li⁺ can effectively sensitize and enhance the fluorescence properties of the host matrix, offering a promising strategy for improving the performance of fluorescent materials.