Multifunctional homoleptic iridium(III) dendrimers towards solution-processed nondoped electrophosphorescence with low efficiency roll-off

Four new iridium dendrimers comprised of bifunctional charge transport peripheral groups have been designed and synthesized. The new complexes not only have good thermal stabilities with high glass-transition temperature up to 284 °C, but also exhibit reduced luminance quenching in neat films due to the sufficient protection of the emissive core from the intermolecular interactions by the peripheries. Solution-processed nondoped yellow phosphorescent organic light-emitting device (PhOLED) achieves a maximum current efficiency of 12.4 cd A−1 and low efficiency roll-off.