ac-dc Electroluminescence

Abstract

The enhancement of electroluminescence, by the superposition of ac and dc voltages, has been observed in certain electroluminescent zinc sulfide powder phosphors. The addition of a dc voltage to an ac voltage exciting visible electroluminescence increases the emission as much as 250 times, under conditions where the dc electroluminescence alone is about equal to the initial ac electroluminescence. Wave form, transient, and spectral measurements show that the increased emission is recombination, at dc-ionized luminescence centers, forced by the ac field.