Preparation and Cathodoluminescence of CaS : Ce and Ca1 − x Sr x S : Ce Phosphors

Abstract

Efficient phosphors consisting of well‐grown crystallites have been prepared by heating calcium carbonate containing an appropriate amount of cerium with sulfurizing flux. The flux consists of either elemental sulfur plus carbonates, or thiosulfates of alkali metals. Because of good crystallinity and large particle size, the phosphors prepared by the flux method are relatively stable against atmospheric carbon dioxide and water, yet have luminescence efficiency comparable to the best prepared by the method. The emission spectrum of the flux‐grown phosphors is similar to that of the prepared by the method, but shifted to shorter wavelengths by about 10–15 nm. phosphors have also been prepared by the flux method. With the increase of the mol fraction of , the lattice parameter increased linearly, and the emission spectrum shifted toward shorter wavelengths.