The Influence of Temperature on the Efficiencies of Zinc Sulfide Phosphors Containing Silver and Cobalt

Abstract

The temperature dependence of the blue fluorescence of zinc sulfide phosphors containing 10−2 per cent silver and 0 10−3 per cent cobalt, under λ 3650 excitation, has been measured over the temperature range of 120–600 K. The form of the temperature dependence curve and its shift toward lower temperatures on the introduction of cobalt are interpreted in terms of the theory of hole migration. The activation energy for hole migration from silver luminescence centers is found to be 0.36 ± .02 electron volts. An estimate of the number of intrinsic killer centers in terms of cobalt centers is obtained.