Intermolecular electronic coupling of 9-methyl-9H-dibenzo[a,[c] carbazole for strong emission in aggregated state by substituent effect

Bright emission of organic luminogens at aggregated state has attracted increasing attention for their potential applications in opto-electronic devices and bio-/chemo-sensors. In this article, upon the introduction of different substituents (Br, Ph and TPh) to the large conjugated core of 9-methyl-9H-dibenzo[a,c]carbazole (DBC) moiety, the resultant luminogens demonstrated PL quantum yields in solid state ranging from 4.81% to 47.39%. Through the systematic investigation of molecular packing, together with theory calculation, the strong intermolecular electronic coupling in the dimers is proved as the main factor to the bright emission in the solid state. The results afforded a new avenue to investigate the intrinsic relationship among the molecular structures, packing modes and emission properties.