Structure, bandgap, photoluminescence evolution and thermal stability improved of Sr replacement apatite phosphors Ca10-xSrx(PO4)6F2:Eu2+ (x = 4, 6, 8)

A series of Sr-replaced solid solution Ca10-xSrx(PO4)6F2:Eu2+ (x = 4, 6, 8) phosphors with apatite structure were engineered and synthesized successfully via the solid-state reaction. The crystal structure, photoluminescence properties and thermal stability enhanced of the Ca10-xSrx (PO4)6F2:Eu2+(x = 4, 6, 8) phosphors were investigated in detail. The existence of oxygen-vacancy-related defect levels in the bandgap and the bandgap reduction caused by these levels were verified by DFT calculated and experiment results.265