Abstract: In this paper, a series of novel Sr_3-xGa₂Ge₄O₁₄∶xDy³⁺ (x=0~0.40) (mole fraction) and Sr_2.68Ga₂Ge₄O₁₄∶0.16Dy³⁺, 0.16M⁺ (M=Li, Na, K) phosphors were prepared by high-temperature solid-phase method. EDS analysis confirms the presence of Sr, Ga, Ge, O and Dy elements in the phosphors. The series Sr_3-xGa₂Ge₄O₁₄∶xDy³⁺ produce strong yellow light emission with 568 nm as the dominant wavelength under 350 nm optical excitation, corresponding to the ⁴F_9/2→⁶H_13/2 transition. The emission spectra of the phosphor show that the emission intensity varies with the increase of Dy³⁺ concentration and reaches its maximum at x=0.16. The co-doping of alkali metal M(M=Li, Na, K) as a charge compensation ion, among which Li⁺ has the most obvious effect on increasing the emission intensity of Dy³⁺, led to the increase of the emission intensity of the phosphor to twice that of the phosphor in the absence of the charge compensation ion. In addition, the fluorescence lifetime of the phosphor decrease continuously with the increase of Dy³⁺ doping concentration. Finally, the CIE chromaticity coordinates and thermal stability of the phosphor Sr_2.68Ga₂Ge₄O₁₄∶0.16Dy³⁺, 0.16Li⁺ are explored, and its CIE chromaticity coordinates are (0.371 9,0.404 6), which are located in the yellow region, and its luminescence intensity at 453 K is about 95.5% of its room temperature luminescence intensity. Therefore, Dy³⁺, Li⁺ co-doped Sr_3-xGa₂Ge₄O₁₄ phosphor is a potential candidate material for display devices and white light LED devices.

Key words: Sr₃Ga₂Ge₄O₁₄∶Dy³⁺, high-temperature solid-state method, charge compensating agent, photoluminescence, thermal stability, fluorescence lifetime