Highly efficient white organic light-emitting devices based on a multiple-emissive-layer structure

Characteristics of white organic light-emitting devices based on phosphor sensitized fluorescence are improved by using a multiple-emissive-layer structure, in which a phosphorescent blue emissive layer is sandwiched between red and green&yellow ones. In this device, bis[(4,6–difluorophenyl)–pyridinato–N,C2] (picolinato), bis(2,4–diphenyl–quinoline) iridium (III) acetylanetonate, fac tris (2-phenylpyridine) iridium, and 5,6,11,12–tetraphenylnaphthacene are used as blue, red, green, and yellow emitters, respectively. The device has a maximum luminance of more than 30,000 cd/m2, a maximum luminous efficiency of 27 cd/A, a maximum external quantum efficiency of 12.4%, and a color rendering index of 81 at 100 cd/m2.