Photoluminescence enhancement in a Na5Y(MoO4)4:Dy3+ white-emitting phosphor by partial replacement of MoO42− with WO42− or VO43−

Abstract

A series of Na5Y(MoO4)4-yAy:Dy3+ (A = WO42−, VO43−; y = 0–0.05) phosphors were synthesized by the combustion method. Some of the MoO42− sites were occupied by WO42− and VO43− anions, which enhanced the luminescence property of Dy3+-doped Na5Y(MoO4)4. XRD results show that the crystal structures of the samples were consistent with the standard Na5Y(MoO4)4 phase. Under excitation at 352 nm, the Na5Y(MoO4)4-yAy:Dy3+ phosphors exhibited a characteristic blue emission at 485 nm and a yellow emission at 577 nm, which originated from the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. White light can be achieved by combining these blue and yellow emissions. After replacing MoO42− with WO42− and VO43− anions in Na5Y(MoO4)4:Dy3+, the luminescence intensity of Dy3+ was significantly improved due to the crystal field effect. The results indicate that Na5Y(MoO4)3.97(WO4)0.03:Dy3+ and Na5Y(MoO4)3.97(VO4)0.03:Dy3+ phosphors have good prospects for application in n-UV-excited w-LEDs.