Ideal bipolar host materials with bis-benzimidazole unit for highly efficient solution-processed green electrophosphorescent devices.

An ideal host material with high triplet energy, suitable HOMO energy level, excellent thermal and electrochemical stability, and bipolar charge carrier transport ability was synthesized. A high external quantum efficiency of 13.7% and a luminance efficiency of 48.2 cd A(-1) with low efficiency roll-off were achieved in solution-processed green electrophosphorescent devices.

9-Phenyl-3,6-bis-(4,4,5,5-tetra-methyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole.

In the title compound, C(30)H(35)B(2)NO(4), the carbazole skeleton is essentially planar (r.m.s. deviation for all non-H atoms = 0.035 Å), and is oriented at a dihedral angle of 65.0 (3)° with respect to the adjacent phenyl ring.