Photoluminescence properties and energy transfer of apatite-type Sr₃LaNa(PO₄)₃ F:Ce³⁺, Tb³⁺ phosphors

A series of apatite-type Sr₃LaNa(PO₄)₃F:Ce³⁺, Tb³⁺ phosphors were synthesized via high temperature solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), the photoluminenscence excitation (PLE) spectra and photoluminescence (PL) spectra were used to characterize samples. And systematic study on micro-morphology, spectral luminescent properties and process of energy transfer in Sr₃LaNa(PO₄)₃F:Ce³⁺, Tb³⁺ phosphors.The results show that Sr₃LaNa(PO₄)₃F:Ce³⁺, Tb³⁺ phosphors with strontium apatite crystal structure, the morphology is irregular. The optimum concentration of Ce³⁺ in Sr₃LaNa(PO₄)₃F:Ce³⁺ was decided to be 0.04, the emission peaks at 340 nm is due to the 5d → ² F_5/2 and ² F_7/2 transitions of Ce³⁺. The PL spectra of Sr₃LaNa(PO₄)₃F:Tb³⁺ phosphor excited by 253.7 nm presents green-emitting light centered at 543 nm. Effective energy transfer from the sensitizer Ce³⁺ to activator Tb³⁺ can be expected in the Ce³⁺ and Tb³⁺ co-doped phosphors Sr₃La_0.96−yNa(PO₄)₃F:0.04Ce³⁺,yTb³⁺. Based on the spectral analysis, The energy transfer efficiency from Ce³⁺ to Tb³⁺ reaches up to 78.6%. The energy transfer mechanism from Ce³⁺ to Tb³⁺ was via the exchange interaction. In Ce³⁺ and Tb³⁺ co-doped Sr₃La_0.96−yNa(PO₄)₃F:0.04Ce³⁺, yTb³⁺ phosphors, the chromatic coordinate was observed with increasing Tb³⁺ co-doping rate on moving from (0.2867, 0.2411) at y = 0.00 to (0.3267, 0.5845) at y = 0.40. (paper)