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

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 Alq3, 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 5.2cd∕A and 2.0lm∕W at 20mA∕cm2. The 20% decay lifetime (t80) of Cs2O doped IBOLED is 270h which is about 1.7 times more stable than that of the conventional OLED (160h) and 2.5 times of Li doped IBOLED (104h).