High-efficiency and heavily doped organic light-emitting devices based on quench-resistant red iridium complex

Highly efficient red phosphorescent organic light-emitting devices had been fabricated using a new iridium complex, bis[2-(9,9-dimethyl-9H-fluoren-2-yl) benzothiazolato-N,C2ʹ]iridium(III) (acetylacetonate) [(fbt)2Ir(acac)] as phosphor. With a high doping concentration of 15 wt%, the device exhibited a maximum luminance efficiency, power efficiency and external quantum efficiency (EQE) of 35.2 cd/A, 21.3 lm/W, 18.2%, respectively, indicating an excellent quench-resistant property of (fbt)2Ir(acac). The results are appealing towards the development of “easy-to-make” OLEDs. It has been demonstrated that the high efficiency arises from more balanced charge carriers in the emissive layer.