Photoluminescence properties of the high-brightness Eu3+-doped KNaCa2(PO4)2 phosphors

A series of red-emitting phosphors Eu3+-doped KNaCa2(PO4)(2) were synthesized by solid-state reaction, and the photoluminescence (PL) properties were also investigated. The excitation spectrum is composed of charge-transfer (CT) of Eu-O and excitation lines of Eu3+ ions. The strongest excitation lines appeared at 393 nm. The emission spectra of KNaCa2(PO4)(2):Eu3+ phosphors exhibit five peaks assigned to the D-5(0)-F-7(1) (J = 0, 1, 2, 3, 4) transitions of Eu3+ and have dominating emission peak at 621 nm under 393 nm excitation. The luminescence intensity enhanced with increasing Eu3+ content and the emission reached the maximum intensity at x = 0.02 in KNaCa2-x(PO4)(2):xEu(3+). The effect of the charge compensators on the emission intensity of the phosphors was investigated. The integral intensity of the emission spectrum of KNaCa1.96(PO4)(2):0.02Eu(3+), 0.02Na(+) excited at 393 nm is about 2.4 times as strong as that of Y2O3:0.05Eu(3+) commercial red phosphor. The color coordinates for KNaCa1.96(PO4)(2):0.02Eu(3+),0.02Na(+) were measured. The results indicate that KNaCa2(PO4)(2):Eu3+ might be a promising phosphor for w-LEDs. (c) 2013 Elsevier B.V. All rights reserved.