Photoluminescent Efficiency of Phosphors with Electronic Transitions in Localized Centers

Abstract

No general theory exists that can predict the efficiency of phosphors with electronic transitions i localized centers. In this paper a survey and discus-sion are given of the correlation between fluorescent properties and chemical properties, like composition and structure. Points of discussion are (a) choice of the activator together with concentration quenching and critical concentra-tion for this phenomenon, (b) influence of the host lattice on the photolumin-escence fficiency for direct excitation of the activator, and (c) energy trans-fer between fluorescent centers. These considerations are i l lustrated by a large number of experimental examples. In this paper we shall restrict ourselves to lumines-cence involving electronic transitions in simple, lo-calized centers. Chemically this means that we shall deal mainly with the so-called oxygen-dominated phosphors. At the moment no general theory exists