SINGLE-LAYER WHITE LIGHT-EMITTING ORGANIC ELECTROLUMINESCENT DEVICES BASED ON DYE-DISPERSED POLY(N-VINYLCARBAZOLE)

Bright single-layer white light-emitting organic electroluminescent de vices were developed by using dye-dispersed poly(N-vinylcarbazole) (PV K). The active layer consists only of one polymer layer that is simply sandwiched between two electrodes, indium-tin oxide, and Mg:Ag. In or der to achieve bipolarity in the single polymer emitter layer, PVK was molecularly dispersed with electron-transporting additives such as bi phenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole. In addition, several fluorescent dyes, having different emission colors, were dispersed as emitting centers. By adjusting the concentration of the fluorescent dy es, white light with a maximum luminescence of 4100 cd/m(2) was obtain ed, which is the brightest white light ever observed for organic elect roluminescent devices. (C) 1995 American Institute of Physics.