Highly efficient, conventional and flexible deep-red phosphorescent OLEDs using ambipolar thiophene/selenophene-phenylquinoline ligand-based Ir(III) complexes

Highly efficient conventional and flexible deep-red phosphorescent OLEDs (PhOLEDs) were developed by using glass (substrate)/indium tin oxide (ITO, transparent conducting electrode, TCE) and polyethylene naphthalate (PEN, substrate)/silver nanowire (AgNW, TCE). A thiophene-phenylquinoline (Th-PQ)-based Ir(III) complex, (Th-PQ)₃Ir, which has already been confirmed as a promising emitter in solution-processed PhOLEDs, and a new selenophene-PQ (Se-PQ)-based Ir(III) complex, (Se-PQ)₃Ir, were verified as emitters in conventional and flexible PhOLEDs. Both (Th-PQ)₃Ir and (Se-PQ)₃Ir exhibited bright red emission (601 nm and 614 nm) in chloroform at room temperature. (Th-PQ)₃Ir showed excellent performance not only in solution-processed devices but also in the conventional and flexible PhOLEDs fabricated by vapor deposition. (Th-PQ)₃Ir exhibited a maximum external quantum efficiency (EQE) of 19.83% and 21.33% in conventional and flexible PhOLEDs, respectively, with stable deep-red CIE coordinates (0.66, 0.34).