Abstract: A series of Eu²⁺ -activated Sr₃LnM(PO₄)₃F(Ln=Gd, La, Y; M=Na, K) phosphors were synthesized by high-temperature solid-phase method. The phase structure, morphology and luminescence characteristics of the samples were characterized by X-ray diffraction, scanning electron microscopy, fluorescence spectroscopy and other test methods. The experimental results demonstrate that the phosphor Sr₃LnM(PO₄)₃F:Eu²⁺ was successfully synthesized, and the particle size of the sample ranges from 2 μm to 10 μm. The phosphor has strong emission in the blue-light region, which is attributed to the 4f⁶5d→4f⁷ transition of the luminescent center Eu²⁺. The emitting color of Eu²⁺ changes from light blue to dark blue and the color purity increases after the transformation of Na to K, which effectively regulates the luminescence of Eu²⁺ in fluorapatite Sr₃LnM(PO₄)₃F. A new strategy by substituting of the secondary layer coordination atom is found to regulate the phosphors color of Eu²⁺.

Key words: rare earth luminescent material, blue phosphor, Eu²⁺, high-temperature solid-phase method, fluorapatite, luminescence regulation, secondary layer coordination atom, color purity