A strategy for developing deep-UV phosphor: Sr₃AlO₄F: Tb³⁺/Sm³⁺

A series of Sr₃AlO₄F:A (A = Tb³⁺, Sm³⁺) phosphors were prepared by solid-state reaction process. The optical properties of Tb³⁺ and Sm³⁺ single-doped or co-doped Sr₃AlO₄F phosphors were researched by means of X-ray diffraction and photoluminescence spectra. Under the excitation of 250–400 nm, all samples exhibited their characteristic emissions of Sr₃AlO₄F:Tb³⁺ (⁵D₃ → ⁷F₅, blue and ⁵D₄ → ⁷F₅, green), Sr₃AlO₄F:Sm³⁺ (⁴G_5/2 → ⁶H_7/2, red). The concentration dependent luminescence intensity of Sr₃AlO₄F:A (A = Tb³⁺, Sm³⁺) phosphors have been investigated in detail. Besides, the energy transfer from Tb³⁺ to Sm³⁺ ion has been researched in the Sr₃AlO₄F host, and the energy transfer mechanism was demonstrated to be a resonant type, through a dipole–quadrupole mechanism on the basis of experimental and theoretical analysis. In addition, white/tunable light can be prepared by changed the doping concentration of Sm³⁺ from 0.03 to 0.12 mol in Sr₃AlO₄F:0.5 % Tb³⁺ under excitation of deep-UV. It is the first time to produce white light emission through Tb³⁺ and Sm³⁺ co-doped Sr₃AlO₄F phosphor.