Adjustment of Bi<sup>3+</sup> Luminescence and Thermal Quenching Properties by B′-Site Ion Substitution Strategy in Double Perovskite CaLaMgSb/TaO<sub>6</sub>:Bi<sup>3+</sup> Phosphor
Ran Xiao, Ning Guo, Chengzheng Jia, Qincan Ma, Ruoting Liu, Ruizhuo Ouyang
Abstract
Thermal quenching has always been one of the most difficult issues in creating high-quality phosphor conversion light-emitting diodes (pc-LED), and a family of strategies are urgently needed to improve the luminescence performance of phosphors at high temperatures. In this contribution, a novel B′-site substitution CaLaMgSb x Ta 1– x O 6:Bi 3+ phosphor was constructed using an ion substitution strategy in the matrix with a green activator Bi 3+ and a novel double perovskite material. When Sb 5+ replaces Ta 5+, a surprising increase in luminescence intensity occurs and the thermal quenching properties are greatly improved. The shift of the Raman characteristic peak to a smaller wavenumber and the reduction of the Bi–O bond length confirm that the crystal field environment around Bi 3+ changes, which has a substantial effect on the crystal field splitting and nepheline effect of Bi 3+ ions, affecting the crystal field splitting energy ( D q ). This results in a corresponding increase of the band gap and the thermal quenching activation energy (Δ E ) of the activator Bi 3+ . From the perspective of D q, the intrinsic relationships among the activator ion band gap, bond length, and Raman characteristic peak changes were analyzed, and a mechanism for regulating luminescence thermal quenching properties was constructed, which provides an effective strategy for improving the promising new materials such as double perovskite.