fac-Tris(2-phenylpyridine)iridium (III)s, covalently surrounded by six bulky host dendrons, for a highly efficient solution-processed organic light emitting device

The fully surrounded complexes by six host dendrons showed high photoluminescence quantum efficiency in a neat film, comparable to in a dilute solution. The surrounding host dendrons efficiently suppressed intermolecular interaction between central Ir complexes and prevented concentration quenching. The complex, (mCP)6Ir, fully surrounded by six carbazole type hosts showed much better performance, compared with the complex, (DAP)6Ir, surrounded by arylamine type hosts, because of well balanced charge injection and transporting in the devices.

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► The dendrimer complexes showed high photoluminescence quantum efficiency.
► Intermolecular interaction between central Ir complexes was suppressed.
► The carbazole complex showed much better OLED performance than the arylamine complex.
► Well balanced charge injection and transporting in the devices are important.