Sr6-xBP5O20:xEu2+ (0.005 ≤ x ≤ 0.08) bluish-green phosphors are prepared by solution combustion method. The photoluminescence excitation spectra show a broad band covering 250-450 nm with a maximum intensity at 353 nm, which matches well with the emission of ultraviolet LED chips. Upon 353 nm excitation, the photoluminescence emission spectra contain two distinct broad emission bands at 408 and 480 nm, which originate from the 4f65d1 →4f7 transitions of Eu2+ ions in Sr3(PO4)2 : Eu2+ and Sr6-xBP5O20 : xEu2+, respectively. The emission intensities at 408 and 480 nm increase with increasing Eu2+ contents up to 5 and 2 mol%, respectively, and then decreased with further its contents.

Keywords: White LEDs, Eu2+-doped phosphor, 4f-5d transition, Sr6-xBP5O20 : xEu2+.