Photoluminescence and electroluminescence from a phosphorescent iridium complex equipped with fluorine moieties

In this paper, we introduce fluorine moieties into a traditional ligand of acetylacetonate, resulting in a fluorine-functionalized ligand of 1,1,1,5,5,5-hexafluoropentane-2,4-dione (HFD). Its corresponding Ir(III) complex of Ir(HFD)(PTZ)2 is also synthesized and fully studied, where PTZ = 2-phenylbenzo[d]thiazole. Its molecular structure is confirmed by single crystal analysis, which suggests that the Ir(III) center occupies a octahedral coordination center. Photoluminescence, thermal stability and electrochemical characteristics of Ir(HFD)(PTZ)2 are investigated. Ir(HFD)(PTZ)2 is found to be a promising emitter with high PL quantum yield, short excited state lifetime, good thermal stability, and proper HOMO/LUMO energy levels, owing to the fluorine substituent effect. Electroluminescence devices with Ir(HFD)(PTZ)2 as the emitting dopant are also constructed to further explore its potential application in organic light emitting diodes. A maximum luminance of 53,000 cd/cm2 is observed from the optimized device.

► A high efficiency phosphorescent Ir(III) emitter is synthesized. ► Its structure, nature and properties are well studied and characterized. ► Multiple quantum well structured devices are fabricated. ► A maximum current efficiency of 28.2 cd/A is realized.