Abstract: A series of K₅Gd (MoO₄)₄:xSm³⁺(x=0~0.10) and K₅Gd (MoO₄)₄:0.04Sm³⁺, yEu³⁺(y=0.03~0.15) red phosphors were synthesized by high-temperature solid-phase method in this paper. The photoluminescence spectra, fluorescence emission spectra, and fluorescence quenching performance of the phosphor were analyzed by X-ray diffraction (XRD), fluorescence excitation spectra, thermal quenching analysis system, and steady-state transient spectrometer. Results show that the samples synthesized by doping Eu³⁺and Sm³⁺into K₅Gd (MoO₄)₄ don't contain impurity phases, and the crystal structure remains unchanged. Under the excitation of 405 nm ultraviolet light, K₅Gd (MoO₄)₄:0.04Sm³⁺and K₅Gd (MoO₄)₄:0.04Sm³⁺, 0.12Eu³⁺can emit excellent red light with the CIE coordinates of (0.6088, 0.3904) and (0.637 3, 0.359 2). In the K₅Gd(MoO₄)₄:xSm³⁺(x=0~0.10) samples, as the Sm³⁺doping concentration increases, the luminescence intensity of the phosphor first increases and then decreases, the optimal doping concentration is x=0.04. In the K₅Gd(MoO₄)₄:0.04Sm³⁺,yEu³⁺(y=0.03~0.15) samples, the luminescence intensity of Eu³⁺first increases and then decreases with increasing Eu³⁺ doping concentration, and concentration quenching occur at y=0.12. When the temperature reaches 373 K, the fluorescence intensity of the K₅Gd(MoO₄)₄:0.04Sm³⁺phosphor sample is 94.69% of that at 293 K, while the fluorescence intensity of the K₅Gd(MoO₄)₄:0.04Sm³⁺, 0.12Eu³⁺phosphor sample is 76.3% of that at 293 K, indicating their good thermal stability. The color coordinate graph shows that, doping of Eu³⁺ leads to the color coordinate shifts slightly from the orange red region to the pure red region. Both K₅Gd(MoO₄)₄:xSm³⁺ and K₅Gd(MoO₄)₄:0.04Sm³⁺, yEu³⁺phosphor samples have the potential to be used as red phosphors for white light LED.

Key words: K₅Gd(MoO₄)₄:xSm³⁺, yEu³⁺, high-temperature solid-phase method, red phosphor, fluorescence quenching, color coordinate