Rare earth oxysulfide luminescent material and preparation method therefor

A method for preparing an oxysulfide luminescent material, comprising:

• mixing and reacting a solution of salt containing metal M with an additive and a reducing agent to prepare a colloid containing M, wherein the metal M is at least one of Ag, Au, Pt, Pd and Cu nanoparticles;
• the additive is at least one of polyvinylpyrrolidone, sodium citrate, cetyl trimethyl ammonium bromide, sodium dodecyl sulfate and sodium dodecyl sulfonate;
• adding the colloid containing M to an ethanol solution of sucrose or glucose to obtain a mixed solution, then heating the mixed solution at 120° C.-200° C. to form a solution of C@M, and centrifuging the solution of C@M, washing and drying to obtain C@M nanospheres;
• @ is coating M with C, and a molar ratio of M to C from sucrose or glucose is in a range of 5×10−4−5×10−2;
• adding the C@M nanospheres to a solution of Ln3+ and Eu3+ according to a molar ratio of Ln3+ to Eu3+ to M which is (2-x):x:y;
• regulating the pH value of the solution to 2-3, followed by adding oxalic acid and regulating the pH value to 8-9 to obtain a liquid suspension of Ln2(C2O4)3:Eu3+@C@M;
• separating the liquid suspension to obtain Ln2(C2O4)3:Eu3+@C@M solid;
• Ln3+ is Y3+, Gd3+ or La3+, and x is in a range of 0<x≦0.2, y is in a range of 0<y≦1×10−2;
• and,
• mixing sulfur powders with the Ln2(C2O4)3:Eu3+ @C@M solid according to a molar ratio of S to Ln3+ which is 1:(2-x), followed by adding a fluxing agent and calcining at 1000° C.-1450° C. to obtain an oxysulfide luminescent material having a general chemical formula of Ln2—xO2S:Eux3+@My;
• Eu3+is doped in Ln2—xO2S to form Ln2—xO2S:Eux 3+having a porous structure, and @ is coating.