Emission color variation of (Ba,Sr)(3)BP3O12:Eu2+ phosphors for white light LEDs

Abstract

A series of alkaline earth borophosphate phosphors, (Ba,Sr)(3)BP3O12 doped with Eu2+ ions, were synthesized by a solid state reaction. Two emission bands at 465 nm and 520 nm were attributed to the f-d transitions of doped Eu2+ ions occupying in two different cation sites in host lattices and emission color variation was observed by substituting the M2+ sites, which was rationalized in terms of two competing factors of the crystal field strength and bond covalence. Green and bluish-white pc-LEDs were fabricated by combination of a 370 nm near-UV chip and composition-optimized Ba3BP3O12:Eu2+ and (Ba,Sr)(3)BP3O12:Eu2+ phosphors, respectively. The series of phosphors may serve as a promising green and bluish-white luminescent materials used in fabrication of near UV-based white pc-LEDs. (C) 2010 Optical Society of America