Supramolecular Charge-Transfer Approach for Tunable and Efficient Circularly Polarized Delayed Fluorescence and...

Achieving efficient circularly polarized luminescence (CPL) with a high luminescence dissymmetry factor (|g_lum|) in purely organic systems is a vibrant and rapidly evolving field of research. Recently, the growing interest in ambient organic phosphors has offered a promising alternative for achieving CPL with remarkable quantum yields by utilizing triplet states. While supramolecular charge-transfer (CT) interactions are well-established to improve |g_lum| by enhancing magnetic transition dipole components, their application to triplet-harvesting organic systems remains unexplored. In this context, our current work introduces a supramolecular strategy to achieve highly efficient and tunable circularly polarized thermally activated delayed fluorescence (TADF) and phosphorescence by the involvement of intermolecular triplet CT states. Through-space intermolecular CT interactions between heavy atom-substituted bis-chromophoric pyromellitic diimides (PmDIs) (acceptors) and achiral phenyl carbazole derivatives (donors) enable one of the most efficient circularly polarized delayed luminescent systems, characterized by a high quantum yield (∼46%) and a significant |g_lum| ∼3.6 × 10⁻². Additionally, the modularity of this non-covalent design allows for the tuning of emission from the orange to deep-red regions by incorporating various donors. The strategy presented here opens new avenues for designing efficient CPL-active organic phosphors.