Synthesis And Luminescent Properties Of Europium Activated Alkaline-earth Metals Phosphate Phosphors

Luminescent material is a key part of the illuminate lights and displays with great appliances and values. In this paper, some kinds of europium ions activated Sr₂P₂O₇ and Ca₃(PO₄)₂ phosphors were synthesized. The structure and luminescent spectra of the samples were investigated; the luminescent properties and the mechanism of the phosphors were analyzed, the chief aspects are given as follows:(1) Synthesis and characterization of orange-red phosphor Sr₂P₂O₇:Eu³⁺, Gd³⁺ by high-temperature solid-state method and a precipitation method. The influences of sintered temperature, holding time, Eu³⁺ and Gd³⁺ ions doping concentration and on luminescent properties of Sr₂P₂O₇:Eu³⁺, Gd³⁺ phosphor were systematically studied. Comparing with Sr₂P₂O₇:Eu³⁺, Gd³⁺ phosphors synthesized by a precipitation method, the one synthesized by a high temperature solid-stated reaction with bigger size and better luminescent properties.(2) A blue-amethyst phosphor Sr₂P₂O₇ (Eu²⁺,Eu³⁺),Cl^- was synthesized, to our knowledge, a reduction from Eu³⁺ to Eu²⁺ in the case of Sr₂P₂O₇ was first report, the abnormal reduction mechanism of Eu³⁺ to Eu²⁺ in Sr₂P₂O₇ (Eu²⁺, Eu³⁺),Cl^- phosphor was discussed. The influences of sintered temperature, holding time, Eu³⁺ and Cl^- ions doping concentration and on the reduction from Eu³⁺ to Eu²⁺ in Sr₂P₂O₇ (Eu²⁺,Eu³⁺),Cl^- phosphor were systematically studied. Based on the foregoing experiential results, the doping of F^-,Cl^-,Br^- ions on the luminescent properties of Sr₂P₂O₇:Eu phosphor were study carefully, it was found that the doping of Cl^- and Br^- help to incorporate Eu²⁺ into Sr²⁺ site in Sr₂P₂O₇ by increasing unit cell volume of the as-prepared samples, which results in the partial reduction of Eu³⁺ to Eu²⁺.(3) A color-controllableβ-Ca₃(PO₄)₂:Eu²⁺,Mg²⁺ phosphor by tuning the Eu²⁺ doping content was prepared by a solid-state precursor method. The influences of sintered temperature, holding time, Eu²⁺ and Mg²⁺ ions doping concentration on the luminescent properties ofβ-Ca₃(PO₄)₂:Eu²⁺ , Mg²⁺ phosphors were systematically studied.β-Ca₃(PO₄)₂:Eu²⁺ , Mg²⁺ could absorb the lights at the wavelength of 250 nm 450 nm and emit the lights at the regions from 380 nm to 600 nm, phosphors emit blue-white, white and kelly light could obtained by tuning the Eu²⁺ doping content. The mechanism of the emission ofβ-Ca₃(PO₄)₂:Eu²⁺,Mg²⁺ was investigated and the substitution of Eu²⁺ to Ca²⁺ w as also studied.(4) The temperature-dependent luminescent spectra ofβ-Ca₃(PO₄)₂:Eu²⁺,Mg²⁺ were obtained. The result indicated that theβ-Ca₃(PO₄)₂:Eu²⁺,Mg²⁺ phosphors with an better excellent thermal luminescence stability than the commercial YAG phosphors and can be suitable for application in white LEDs...