White Light Emitting Thin Film Electroluminescent Cells with SrS:Pr,Ce Active Layer and Their Application to Multicolor Electroluminescent Devices

Abstract
White light emission with a maximum luminance of 950 cd/m2 under a 1 kHz sinusoidal wave drive condition was obtained from a SrS:Pr,Ce thin film electroluminescent (TFEL) cell. The EL spectrum was found to be composed of emissions from Pr3+ and Ce3+ ions. Spectral change was studied by varying the concentration of activator ions and the luminance for a unit concentration of Ce3+ ions was estimated to be three times as large as that of Pr3+ ions. By using color filters on the SrS:Pr,Ce TFEL cell, multicolor (red, blue, green) EL devices with suitable color coordinates and balanced luminance levels were developed.