Infrared Light Stimulation and Quenching in ZnS Phosphors

Abstract

The effects of infrared on the luminescence of three ZnS phosphors (activated with Cu, Ag, and Cu-Pb) at liquid nitrogen temperatures has been investigated. The transient stimulation and permanent quenching (or enhancement) was determined at various wavelengths in the emission spectrum of the ultraviolet-excited phosphors. Two infrared bands were used, one at about 0.75, the other at about 1.3. The effect of the infrared varies with the emission wavelength but not sufficiently to explain discrepancies with the usually accepted phosphor model. A modification of this model consisting of a coupled trapped electron-ionized activator complex is proposed, and the consequences are discussed.