Influence of mechanical milling and annealing atmosphere on the photoluminescence properties of ZnS:Cu,Cl phosphors

ZnS:Cu,Cl phosphors were synthesized by high temperature (1200°C) solid state reaction, mechanical milling (rotation speed = 0,75,150,250 and 350r/ min) and the final annealing at 750°C for 1 h in different atmospheres (hydrogen sulfide, sealed evacuated silica tubes and Ar). The as-prepared phosphors were characterized by X-ray powder diffraction and photoluminescence spectra. It was found that mechanical milling led to width increases of diffraction peaks. Both the mechanical milling and atmosphere play important roles in the photoluminescence performance of the phosphors. Some phosphors prepared by the three-step method possess higher photoluminescence performances than the normal one-step method. Particularly, the luminescence intensity of the phosphor milled at the rotation speed of 75 r / min and then treated in Ar atmosphere is about one time higher than that prepared by the normal one-step process.