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: ≈1:1 P or M-enantiomer for α-cocrystal, alternated P/M-column stacking in mesmeric 2:3 β-cocrystal, and segregated stacking of γ-cocrystal. As a result, α-cocrystal exhibits bright solid-state red fluorescent, β-cocrystal shows significant optical waveguide behavior with a low optical loss coefficient of ≈0.018 dB µm⁻¹, and no visual light emission is observed for γ-cocrystal under ultraviolet radiation. Interestingly, the α-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.