Comparative investigation of photoluminescence and long-lasting phosphorescence properties in the (CaO-CaBr2-SiO2):: Eu2+ phosphor system

We developed a (CaO - CaBr2 - SiO2) : Eu2+ long-lasting phosphor system. The photoluminescence (PL) spectrum reveals that two quite different emission bands can be observed, in which is presumed that Eu2+ ions occupy two types of sites, Eu(1) and Eu(2). The phosphor shows strong blue and weak greenish yellow emission under 365 nm UV light. The long-lasting phosphorescence (LLP) spectrum testifies to the existence of two types of emission centers, but the corresponding emission intensity is reversed. It emits obvious greenish yellow light and shows strong long-lasting phosphorescence in the dark. The possible mechanism of the unusual PL and LLP emission is also discussed. (c) 2006 The Electrochemical Society.