Synthesis and photoluminescence properties of Eu doped Sr9Sc(PO4)7 phosphors for white light-emitting diodes

A series of Eu²⁺-activated Sr₉Sc(PO₄)₇ yellowish-green emitting phosphors were synthesized by conventional solid-state reaction. The photoluminescence (PL) properties and concentration quenching mechanism of the as-prepared phosphors were investigated. The emission spectrum exhibits a broad and asymmetric band peaking at 510 nm, which corresponds to the 4f⁶5d¹→4f⁷ transition of Eu²⁺. The excitation spectrum exhibits a broad band extending from 250 to 450 nm, which matches well with the emission of near ultraviolet (n-UV) chips (350–430 nm). Non-radiative transitions between Eu²⁺ ions in the Sr₉Sc(PO₄)₇ host have been demonstrated to be attributable to dipole–dipole interactions, and the critical distance was calculated to be 23.1 Å. These results indicate that Sr₉Sc(PO₄)₇:Eu²⁺ phosphor could serve as a promising candidate for application in n-UV white-light LEDs.