Fabrication of highly efficient organic electroluminescent devices

Abstract

Efficient organic electroluminescent (EL) devices were fabricated by using a highly fluorescent aluminum complex, tris(4-methyl-8-quinolinolato)aluminum(III) (Almq3), as an emitter layer. In addition to using this complex, a multilayer device structure, consisting of a hole-injecting layer, a hole transport layer, a dye-doped Almq3 emitting layer, and an electron transport layer, was employed in order to reduce the driving voltage as well as to maximize carrier recombination efficiency. From this device, a maximum luminance of over 140 000 cd/m2 and an external quantum efficiency of 7.1% was observed, which is the highest efficiency ever reported for organic EL devices.