Planar Chiral Carbazole‐Naphthalene Bisimide Hetero‐Cyclophane for Circularly Polarized Delayed Fluorescence

Abstract

ABSTRACT Chiral organic chromophores with circularly polarized thermally activated delayed fluorescence (CP–TADF) provide great prospects as circularly polarized luminescence (CPL) emitters owing to the involvement of long‐lived triplet excitons. Here, we construct a tailored planar chiral hetero‐cyclophane ( NBICz–Cy ) composed of 1,2:5,6–naphthalene bisimide (1,2:5,6–NBI) and carbazole (Cz) units, which functions as an efficient solution‐state CP–TADF emitter. Comprehensive photophysical studies reveal pronounced delayed fluorescence in the orange‐red region, with a quantum yield (QY) of 19% in deaerated solution and 12% in an aerated solution‐processable matrix. Single‐crystal XRD analysis unravels a through‐space charge‐transfer (CT) interaction between the NBI and Cz moieties, being responsible for delayed fluorescence. The inherent prochirality of the 1,2:5,6–NBI moiety imparts planar chirality in the cyclophane framework, resulting in CP–TADF in both solution and solid state with |g lum | values of ∼ 2.5 – 3.3 × 10 −3 .