Combustion synthesis and luminescence properties of NaY1−xEux(WO4)2 phosphors

The red phosphors NaY1−xEux(WO4)2 with different concentrations of Eu3+ were synthesized via the combustion synthesis method. As a comparison, NaEu(WO4)2 was prepared by the solid-state reaction method. The phase composition and optical properties of as-synthesized samples were studied by X-ray powder diffraction and photoluminescence spectra. The results show that the red light emission intensity of the combustion synthesized samples under 394 nm excitation increases with increase in Eu3+ concentrations and calcination temperatures. Without Y ions doping, the emission spectra intensity of the NaEu(WO4)2 phosphor prepared by the combustion method fired at 900 °C is higher than that prepared by the solid-state reaction at 1100 °C. NaEu(WO4)2 phosphor synthesized by the combustion method at 1100 °C exhibits the strongest red emission under 394 nm excitation and appropriate CIE chromaticity coordinates (x=0.64, y=0.33) close to the NTSC standard value. Thus, its excellent luminescence properties make it a promising phosphor for near UV InGaN chip-based red-emitting LED application.