Efficient fluorescent white organic light-emitting diodes using co-host/emitter dual-role possessed di(triphenyl-amine)-1,4-divinyl-naphthalene

Efficient fluorescent white organic light-emitting diodes with low carrier-injection barriers were fabricated with device structure of indium tin oxide/N,N'-bis-(1-naphthy)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine/white emission layer/1,3, 5-tris(N-phenyl-benzimidazol-2-yl)benzene/lithium fluoride/aluminium. By blending in the blue host of 1-butyl-9,10-naphthalene-anthracene in the emissive layer an efficient electro-luminescent greenish-blue co-host of di(triphenyl-amine)-1, 4-divinyl-naphthalene, with the doping of a trace amount of red dye of 4-(dicyano-methylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran, bright and colour-stable white emission with high power-efficiency of 14.6 lm/W at 100 cd/m(2) or current efficiency of 19.2 cd/A at 300 cd/m(2) or 18.7 cd/A at 10,000 cd/m(2) was obtained. The resulted synergistic increase in brightness and efficiency may be attributed to the presence of cascading new routes with comparatively lower electron injection barrier. (c) 2007 Published by Elsevier B.V.