White emission enhancement of Ca5(PO4)3Cl:Dy3+ phosphor with Li+/Eu3+ co-doping for white light-emitting diodes

Dysprosium doped chlorapatite, Ca-5(PO4)(3)Cl:Dy3+ white-emitting phosphors were synthesized by a solid-state reaction method. The effects of synthesis temperature, Dy3+ doping concentration, Eu3+ co-doping concentration and charge compensator Li+ co-doping on the crystal structures and luminescence properties of Ca-5(PO4)(3)Cl:Dy3+ samples were investigated. Ca-5(PO4)(3)Cl:Dy3+, Eu3+ and Ca-5(PO4)(3)Cl:Dy3+, Li+ phosphors with standard Ca-5(PO4)(3)Cl structure were prepared by heating above 900 A degrees C, and the doped Dy3+, Eu3+/Li+ ions had no effect on the crystal structure. Under ultraviolet excitation at 366 nm, the emission spectra of Ca-5(PO4)(3)Cl:Dy3+ phosphors exhibited two characteristic peaks of Dy3+ at 484 and 577 nm, which corresponding to the F-4(9/2)-> H-6(15/2) and F-4(9/2)-> H-6(13/2) electron transitions, respectively. Both blue and yellow emissions within a single-component host would constitute the white light. The white emission intensity of Ca-5(PO4)(3)Cl:Dy3+ was enhanced markedly by Li+ co-doping as charge compensator. Moreover, Eu3+ co-doped Ca-5(PO4)(3)Cl:Dy3+ phosphor showed an excellent warm white light with high chromaticity coordinates and low correlated color temperature though an additional red emission of Eu3+. The results indicate that these Ca-5(PO4)(3)Cl:Dy3+, Eu3+/Li+ phosphors have potential applications in the field of white light-emitting diodes as single-component white-emitting phosphors.