High Efficiency Blue Organic Electroluminescent Devices Having a Metal-Doped Electron Injection Layer

We report high efficiency blue organic electroluminescent (OEL) devices having a metal-doped electron injection layer at the cathode interface. The typical device structure is an indium-tin oxide (IIO)/arylamine derivative (α-NPD)/blue emitting distyrylarylene derivative/metal-doped organic electron injection layer/Al. The device efficiency is dependent on the work function of the dopant metals and the host organic materials composing the metal-doped layer. A device having Cs-doped bathophenanthroline (Bphen) layer as the cathode interface layer exhibited a high luminous efficiency of 9 lm/W and an external quantum efficiency of 6.5% at luminance of 300 cd/m 2, which are the highest values reported for blue organic EL devices