High efficiency and stable-yellow phosphorescence from OLEDs with a novel fluorinated heteroleptic iridium complex

•A novel Ir–bt type complex with multi-fluorine functionalization was synthesized.•The complex exhibited high quantum yield (0.56) and short lifetime (0.37 μs).•Influence of fluorine atoms on photophysical properties of the complex was investigated.•Highly efficient yellow OLEDs using the complex as emitter were fabricated.•Stable yellow electrophosphorescence from the device was achieved.

The performance of a heteroleptic bis-cyclometalated iridium complex based on 2-(2,3,4-trifluorophenyl)benzo[d]thiazole [(tfbt)2Ir(acac)] was investigated as a new phosphorescent emitter in OLEDs. The devices showed very high efficiency at various dopant concentrations and maximum efficiency was achieved at 6 wt% dopant concentration. A comparison of the performances of phosphorescent OLEDs with the new emitter versus those with prototype-based (bt)2Ir(acac) emitter revealed a remarkable improvement of efficiency at all dopant concentrations. These preliminary results obtained with the tfbt-based emitter indicate that this family of cyclometalated ligands with multi-fluorine functionalization is a promising compound for the development of highly emissive complexes.

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