Transparent white organic light-emitting devices with a LiF/Yb:Ag cathode

Transparent white organic light-emitting devices with a LiF/Yb:Ag cathode are reported. The device with a structure of indium-tin oxide/ 4,4',4 '' -tris(3-methylphenyl-phenylamino)-tripheny-lamine (40 nm)/N,N'-bis-(1-naphthyl)- N,N' -diphenyl- 1,1'-biph-enyl-4,4'-diamine (NPB: 7 nm)/rubrene (0.1 nm)/NPB(3 nm)/2,2',2 ''-(1,3,5-phenylene) tris(1-phenyl- 1H- benzimidazole (30 nm)/tris (8-hydroxyquinoline) aluminum (20 nm)/LiF (0.5 nm)/Yb:Ag (15 nm, volume ratio 1:1) shows few differences in luminance and color purity from both sides. For instant, at a driving voltage of 10 V, the luminance and CIE coordinates of 1173/1488 cd/m(2) and (0.3482,0.3596)/(0.3508,0.3352) are obtained from top/bottom sides. CIE coordinates of the device from both sides are voltage independent, and the maximum total electroluminescence efficiencies of the device are 4.6 cd/A. (C) 2009 Optical Society of America