Control of Luminescence by Charge Extraction

Abstract

It has been discovered that the application of a potential of a few volts to phosphors of the ZnS group can quench the fluorescence. The effect has been observed in single-crystal and recrystallized wafers of the phosphors by illuminating one side with nonpenetrating light and applying a field, through suitable contacts, normal to the illuminated surface. With the illuminated surface negative, the fluorescence is reduced by an amount dependent on the voltage for as long as the voltage is maintained, and total extinction can often be obtained. The luminescent output follows variations in the applied voltage up to a maximum frequency which depends on the fluorescence time constant.