Novel self-host heteroleptic green iridium dendrimers based on carbazole dendrons for solution-processable non-doped phosphorescent organic light-emitting diodes.

Several novel green-emitting iridium dendrimers has been successfully designed and synthesized with carbazole as the dendron, which is covalently attached to the emissive bis[2-(2-dibenzothienyl)pyridine]picolate iridium(III) [(DBTPy) 2 Irpic] core through a nonconjugated link to form an efficient self-host system for nondoped electrophosphorescent device applications. All the iridium dendrimers display green emission, possess good thermal stability and high photoluminescence quantum yields. As well as, non-doped solution-processed OLEDs were successfully fabricated based on the resulting Ir-1, Ir-2 and Ir-3 as green-emitting phosphors. By increasing the density of carbazole dendrons at the edge of the emissive core, luminescence self-quenching caused by the intermolecular interactions in the solid state can be significantly reduced. Therefore, the OLEDs based on Ir-3 show the best performances with a maximal luminous efficiency of 0.24 cd/A and a maximum brightness of 2520 cd/m2. This work will shed light on the development of novel self-host phosphorescent iridium dendrimers for solution processable nondoped electrophosphorescent devices. Novel green-emitting iridium dendrimers with carbazole as the dendron and bis[2-(2-dibenzothienyl)pyridine]picolate iridium(III) as core through a nonconjugated link have been successfully designed and synthesized to form an efficient self-host system for nondoped electrophosphorescent device applications. Image 1 • Three novel green-emitting iridium dendrimers has been successfully synthesized. • The iridium dendrimers use carbazole as dendron and (DBTPy) 2 Irpic as core. • Nondoped solution-processed OLEDs were fabricated with these iridium dendrimers. • By increasing the density of carbazole dendrons, self-quenching can be reduced. [ABSTRACT FROM AUTHOR]