Effect of zinc metal addition on microstructural evolution of Zn0.22Cd0.78S phosphors studied by transmission electron microscopy

The effect of zinc powder addition on the microstructural evolution of fine Zn0.22Cd0.78S:Ag, Cl phosphor particles was investigated in relation to th e luminescent property of phosphors. The phosphor microstructures were anal yzed by high-resolution transmission electron microscopy (HRTEM) using the ultramicrotome technique for specimen preparation. The phosphor baking proc ess at 480 degreesC for 30 min in air results in significant damage to the surface structure of the phosphors due to the decomposition and oxidation o f the phosphor itself. The addition of zinc metal powders into the Zn0.22Cd 0.78S phosphors suppresses the oxidization and decomposition of phosphors b y oxidizing zinc metal during the baking process in air. The oxidation of t he zinc powders during baking provides the baking furnace with less oxidizi ng atmosphere for phosphor particles. The structure of phosphors, especiall y at the surface region, is much less degraded compared to the phosphors ba ked with no zinc metal addition. (C) 2000 Kluwer Academic Publishers.