Stoichiometric and Chiral Stacking Tailoring of Dibenzocarbazole Analog-TCNB Charge-Transfer Cocrystals via Supramolecular Assembly for Variable Optical Behaviors

In this paper, three new donor-acceptor complex forms (zBC) containing a helical-shape dibenzocarbazole analog (DBCz) as the electron donor and 1,2,4,5-tetracyanobenzene (TCNB) as the electron acceptor via a simple solution-processing strategy are reported. The beginning components self-assembled into supramolecular frameworks with glamorous alignment modes and different molar ratios: approximate to 1:1 P or M-enantiomer for alpha-cocrystal, alternated P/M-column stacking in mesmeric 2:3 beta-cocrystal, and segregated stacking of gamma-cocrystal. As a result, alpha-cocrystal exhibits bright solid-state red fluorescent, beta-cocrystal shows significant optical waveguide behavior with a low optical loss coefficient of approximate to 0.018 dB mu m(-1), and no visual light emission is observed for gamma-cocrystal under ultraviolet radiation. Interestingly, the alpha-zBC crystal is not only emissive but also chiroptically active with dissymmetry factor (g(lum)) of 0.004. This study on chiral stacking tailoring paves a way for functional design of organic charge-transfer complex toward application in high-performance organic optoelectronics.