Near UV-pumped yellow-emitting Sr9MgLi(PO4)7:Eu2+ phosphor for white-light LEDs

Abstract

Laboratory discovery of new phosphors for white-light light-emitting diodes (WLEDs) is still an imperative challenge. A new yellow-emitting Sr9MgLi(PO4)7:Eu2+ phosphor was discovered based on the mineral-inspired prototype evolution and new phase construction strategy proposed by our group. Sr9MgLi(PO4)7:Eu2+ has been synthesized by using a high temperature solid-state method, and its phase structure and luminescence properties have been investigated in detail, and applied in WLED lamp. Sr9MgLi(PO4)7 phase is derived from the β-Ca3(PO4)2-type mineral structure. Upon 365 nm UV light excitation, the Sr9MgLi(PO4)7:Eu2+ phosphor exhibits a broad emission band from 450 nm to 700 nm. The white-light LED lamp was fabricated based on the phosphor blends of the composition-optimized yellow-emitting Sr9MgLi(PO4)7:Eu2+ and commercial blue-emitting BaMgAl10O17:Eu2+, and a 365 nm UV chip was used as the excitation source. The Ra, CCT value and CIE of the as-fabricated LEDs were found to be 83, 5,612 K, and (0.324, 0.358), respectively. All the results indicate that Sr9MgLi(PO4)7:Eu2+ could be potential in the development of UV-pumped white-light LEDs.