Color-tunable phosphor of Sr(3)YNa(PO(4))(3)F:Tb(3+)via interionic cross-relaxation energy transfer

A series of color-tunable Sr(3)YNa(PO(4))(3)F:Tb(3+) 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 Tb(3+) concentrations, which is attributed to the enhanced cross-relaxation (CR) between Tb(3+) ions, as described by ((5)D(3), (7)F(6))–((5)D(4), (7)F(0)). 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 Tb(3+) ions is evaluated to be 18.1 Å. In addition, the thermal quenching mechanism of Sr(3)YNa(PO(4))(3)F:Tb(3+) is also investigated. At the general working temperature of an LED (423 K), the luminescence intensity still maintains 81% and 92% with the Tb(3+) concentration of 10 and 30 mol%, respectively, indicating an excellent thermal quenching performance of Tb(3+). Due to the good optical and thermal properties, the Sr(3)YNa(PO(4))(3)F:Tb(3+) phosphor can be used as a promising green emitting phosphor candidate in the field of white light applications.