Li⁺ Ion Doping Induced Photoluminescence Enhancement and Anti-Thermal Quenching of LaOBr: Eu³⁺ Phosphor

Thermal quenching (TQ) seriously restricts the practical applications of phosphor-converted white-lighting-emitting diodes (pc-WLEDs), especially for high-power operations. Here, a novel red-emitting phosphor LaOBr: Eu³⁺ with layered tetragonal structure was successfully synthesized by a solid-state reaction approach. Due to additional Li⁺ ion doping into LaOBr: Eu³⁺, the as-obtained phosphors manifest excellent performance with high internal quenching efficiency (IQE) (58.6%) and anti-thermal quenching performance. It is demonstrated that the structural rigidity of the lattice matrix could be enhanced with the introduction of Li⁺ ions and, then, it contributes to the suppression of TQ and the improvement of the luminescence efficiency. Furthermore, a fabricated WLED based on the LaOBr: Eu³⁺, Li⁺ sample displays an appropriate color rendering index (CRI = 83.1) and correlated color temperature (CCT = 4719 K), revealing the great potential of the as-obtained red phosphor for pc-WLEDs.