Chiral Organic Crystals of Binaphthyl Derivatives: Crystallinity-Enhanced CPL Performance

Binaphthyl-based chiral organic molecules have attracted considerable attention due to their potential in circularly polarized luminescence (CPL). In this study, three pairs of enantiomerically pure binaphthyl derivatives (R/S-1, R/S-2, and R/S-3) were synthesized, and their optical properties were systematically investigated in both the amorphous and crystalline states. Notably, the crystalline forms exhibited significantly enhanced CPL activity compared to their amorphous counterparts, with R/S-3 showing a nearly 10-fold increase in |glum|. Single-crystal X-ray diffraction analysis revealed that enhanced intermolecular interactions and highly ordered 21-helical packing promote efficient exciton migration and chiral amplification, accounting for the improved CPL performance. This work provides new insights into CPL enhancement via crystalline-state engineering and offers guidance for developing practical CPL-active materials.