Color-tunable phosphor of Sr3YNa(PO4)3F:Tb3+ via interionic cross-relaxation energy transfer

RSC Adv. 2018 Jul 16;8(45):25378-25386. doi: 10.1039/c8ra05515g.

Abstract

A series of color-tunable Sr3YNa(PO4)3F:Tb3+ phosphors with a fluorapatite structure were synthesized by a traditional high-temperature solid state reaction. The emitting color tuning from blue to green can be observed by gradually increasing Tb3+ concentrations, which is attributed to the enhanced cross-relaxation (CR) between Tb3+ ions, as described by (5D3, 7F6)-(5D4, 7F0). The CR process is analyzed based on the Dexter and Inokuti-Hirayama model, which is assigned to the electric dipole-dipole interaction. The energy transfer critical distance between Tb3+ ions is evaluated to be 18.1 Å. In addition, the thermal quenching mechanism of Sr3YNa(PO4)3F:Tb3+ is also investigated. At the general working temperature of an LED (423 K), the luminescence intensity still maintains 81% and 92% with the Tb3+ concentration of 10 and 30 mol%, respectively, indicating an excellent thermal quenching performance of Tb3+. Due to the good optical and thermal properties, the Sr3YNa(PO4)3F:Tb3+ phosphor can be used as a promising green emitting phosphor candidate in the field of white light applications.