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

Abstract A series of red-emitting phosphors Eu 3+ -doped KNaCa 2 (PO 4 ) 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 Eu 3+ ions. The strongest excitation lines appeared at 393 nm. The emission spectra of KNaCa 2 (PO 4 ) 2 :Eu 3+ phosphors exhibit five peaks assigned to the 5 D 0 – 7 F J ( J  = 0, 1, 2, 3, 4) transitions of Eu 3+ and have dominating emission peak at 621 nm under 393 nm excitation. The luminescence intensity enhanced with increasing Eu 3+ content and the emission reached the maximum intensity at x  = 0.02 in KNaCa 2− x (PO 4 ) 2 : x Eu 3+ . The effect of the charge compensators on the emission intensity of the phosphors was investigated. The integral intensity of the emission spectrum of KNaCa 1.96 (PO 4 ) 2 :0.02Eu 3+ , 0.02Na + excited at 393 nm is about 2.4 times as strong as that of Y 2 O 3 :0.05Eu 3+ commercial red phosphor. The color coordinates for KNaCa 1.96 (PO 4 ) 2 :0.02Eu 3+ ,0.02Na + were measured. The results indicate that KNaCa 2 (PO 4 ) 2 :Eu 3+ might be a promising phosphor for w-LEDs.