Self-host yellow iridium dendrimers based on carbazole dendrons: synthesis, characterization and application in solution-processed organic light-emitting diodes

On the basis of different generation carbazole dendrons, a series of self-host yellow Ir dendrimers (Y-G0, Y-G1 and Y-G2) have been successfully synthesized and characterized in detail. It is found that the peripheral dendrons can effectively reduce the intermolecular interactions between emissive Ir cores, as verified by the increased photoluminescence quantum yields and film lifetimes. Among these dendrimers, Y-G2 bearing the second generation dendrons shows the best non-doped device performance, revealing a peak luminous efficiency of 20.2 cd/A. The value is nearly twice that of Y-G0 without any dendrons, which could be further improved to 32.1 cd/A by dispersing Y-G2 into a host matrix. We believe that this work will shed light on the development of highly efficient yellow phosphorescent dendrimers with a self-host strategy.