Study on relationship of luminescence in CaS:Eu,Sm and dopants concentration

Abstract

In order to study different characteristic luminescence of Eu 2+ and Sm 3+, delayed photoluminescence (DPL) and infrared stimulated luminescence (ISL) spectra of CaS doped with europium and samarium have been investigated. The influence of Eu and Sm concentration on luminescence of Eu 2+ in photoluminescence (PL) and ISL was respectively studied. It was found that, at low doping levels, PL emission intensity of Eu 2+ increased linearly with increment of Eu, while decreased linearly with increment of Sm. However, further increment of Eu and Sm in CaS:Eu,Sm could not increase either the luminescent centres of Eu 2+ or electron trapping sites of Sm 3+. Different local environment of Eu 2+ and Sm 3+ in the lattice position is thought to be the cause of all observed luminescence phenomena. Finally, the maximum emission in ISL was obtained at 1000 ppm europium and 750 ppm samarium.