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

Abstract

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 → 2F5/2 and 2F7/2 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 Sr3La0.96−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 Sr3La0.96−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.