Light- and Heat-Induced Reversal of Circularly Polarized Luminescence in a Single Molecule

Switching the handedness of circularly polarized luminescence (CPL) at the molecular level remains a challenge in the development of responsive chiral materials. We report a light-driven molecular motor covalently linked to two perylenediimide (PDI) chromophores, enabling reversible and directional modulation of CPL. The different motor states, which are accessible in a unidirectional fashion via light-irradiation and thermal helix inversion steps, respectively, display significantly distinct chiroptical properties. In addition, our system allows switching of the chiral induction process and hence, the observation of a CPL signal. The present work discloses the first example of reversible CPL sign inversion triggered by light irradiation at the single molecular level, offering a new starting point for designing emitters with light-responsive chirality modulation.