Solution-processed solid solution of a novel carbazole derivative for high-performance blue phosphorescent organic light-emitting diodes.

Blue light: Incorporation of two fluorenyl rings into a phenyl group at the C9 position of fluorene builds a bulky and rigidly tetrahedral framework, which is functionalized by two carbazole groups. This molecule possesses excellent thermal and morphological stability, miscibility to the phosphorescent dopant, and high triplet energy, leading to narrow blue phosphorescent emission.