Adjustment of Bi 3+ Luminescence and Thermal Quenching Properties by B'-Site Ion Substitution Strategy in Double Perovskite CaLaMgSb/TaO 6 :Bi 3+ Phosphor.

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.