Spectral and kinetic properties of electroluminescence of ZnS:Cu powder   in polymer structure
  Spectral and kinetic measurements of the light output have been made for AC electroluminescent structure. ZnS:Cu is luminescence active layer in the structure. In kinetic measurements, excitation was by rectangular wave voltage pulse of 1 ms duration. During the excitation the structure emits blue-green light. The maximum of the spectrum lies at about 455 nm. 
E. Chimczak, T. Dunaj, M. Bertandt, A. Wieczorek, G. Neunert and G.   Chimczak and M.Cie\.z and M. {\L}ukasik
cond-mat.mtrl-sci physics.optics