XV. Luminescence of the Sulphide Phosphors

Publisher Website
Google Scholar
Abstract
Detailed theoretical and experimental studies suggest that cation vacancies cause the 0-46μ 0-54μ luminescence bands of ZnS, the 0-8μ1.01μ, bands of CdSe and the 0.92μ, 1.2μ, bands of CdSe. Both the blue and green bands arise from the same centre. Anion vacancies in the lattice are thought to provide the centres for the 0.67μ. red emission of ZnS and the 2.5μ. emission of HgS. All these are interionic transitions between ions of the fundamental lattice. Overlap due to partially co-valent binding ensures that there is appreciable probability of such transitions. Two energy levels in the forbidden zone are created by breaking a double homopolar bond and these are undisturbed by the presence of Cu+ ions in the vacancy. The recently investigated infrared emissions of the sulphides are assumed to be transitions between 3p-3s mixed states, which have been perturbed by the absence of a neighbouring cation into the forbidden zone. The binding is found to be about 36% covalent.

This publication has 11 references indexed in Scilit: