Electroluminescence from ZnS lumocen devices: Spectra and lifetime measurements

The emission spectra of the following molecular centers in ZnS lumocen films have been studied over the range from 3500Å to 1.1µ and have been related whenever possible, to known energy level schemes: PrF3, NdF3, SmF3, TbF3, DyF3, ErF3, EuF3, HoF3, EuF2, CrF3, and MnF2. In addition, lifetimes have been measured for the fluorescing states giving rise to the most prominent emission in the first five of the above. The devices were of the following configuration: Electrode 1 - dielectric - ZnS lumocen film approximately 2000Å thick formed by co-evaporation of ZnS powder and fluoride - Electrode 2 of thin gold serving also as the emission window.