Highly efficient and inverted tandem organic light-emitting devices using a MoO_3/AI/MoO_3 charge generation layer

摘要

We present bottom-emission, inverted, tandem phosphorescent organic light-emitting devices (PHOLEDs) using a multilayer charge generation layer (CGL) of MoO3/Al/MoO3 (MAM), which exhibits a maximum external quantum efficiency of 40% and current efficiency of 120 cd/A. In this inverted tandem structure, the feature of MAM shows a high optical transmittance (approximately 90%) in visible light, an efficient charge generation property, and a relatively smooth morphology (root mean square of similar to 0.336 nm) providing an efficient CGL to connect the bottom and top display units. In addition, the device structure of ITO/LiF/TAPC/MAM/BPhen: CS2CO3/BPhen/LiF/Al was proposed to capacitance characterization, and the results demonstrated that using the ultrathin Al of similar to 2 nm in a MAM structure exhibited a more efficient CGL for high performance inverted tandem PHOLEDs. (c) 2017 The Japan Society of Applied Physics