Effect of LiCl flux on the red ZnS:Sm phosphors fired in reductive atmosphere

ZnS:Sm phosphors with strong red emission can be prepared by solid state reaction fired in a reductive atmosphere. Using LiCl as the fluxing agent favors the crystal growth of ZnS as well as increasing the content of the hexagonal phase in ZnS. The higher content of the hexagonal phase and evenly-distributed samarium compound on ZnS can induce greater light energy absorption and result in better photoluminescence emission intensity and color purity. The red emission intensity of ZnS:Sm phosphors is increased about 5 times with the addition of LiCl flux agent compared with the addition of Sm alone without any flux agent. The optimal concentration of LiCl flux is 2.0 mol% for ZnS with doping 0.2 mol% Sm phosphors fired in a reductive atmosphere.