Stable inverted bottom-emitting organic electroluminescent devices with molecular doping and morphology improvement

Abstract

Stable inverted bottom-emitting organic light-emitting diodes (IBOLEDs) have been investigated by inserting n-type Cs2O dopant between indium-tin oxide bottom cathode and Alq(3), the combination of which not only improved the morphology of organic layer but enhanced the lifetime of the IBOLED. This n-type doped IBOLED achieved efficiencies of 5.2 cd/A and 2.0 lm/W at 20 mA/cm(2). The 20% decay lifetime (t(80)) of Cs2O doped IBOLED is 270 h which is about 1.7 times more stable than that of the conventional OLED (160 h) and 2.5 times of Li doped IBOLED (104 h). (c) 2006 American Institute of Physics.