High-efficiency hybrid organic-inorganic light-emitting devices

We report efficient red, orange, green and blue organic-inorganic light emitting devices using light emitting polymers and polyethylenimine ethoxylated (PEIE) interlayer with the respective luminance efficiency of 1.3, 2.7, 10 and 4.1 cd A(-1), which is comparable to that of the analogous conventional devices using a low work-function metal cathode. This is enabled by the enhanced electron injection due to the effective reduction of the ZnO work-function by PEIE, as well as hole/exciton-blocking function of PEIE layer. Due to the benign compatibility between PEIE and the neighboring organic layer, the novel phosphorescent organic-inorganic devices using solution-processed small molecule emissive layer show the maximum luminance efficiency of 87.6 cd A(-1) and external quantum efficiency of 20.9% at 1000 cd m(-2). (C) 2015 Elsevier B.V. All rights reserved.