Control of Circularly Polarized Luminescence in Cholesteric Luminescent Liquid Crystals: From FRET to Exciton...

Achieving circularly polarized luminescent (CPL) materials with tunable wavelength and high dissymmetry factor (g_lum) still faces great challenges. Cholesteric luminescent liquid crystal (N*LLC) is one of the most promising chiral systems to solve the above challenges. In this work, a pair of luminescent chiral inducers R1/S1 were synthesized by incorporating a rhodamine luminophore to a binaphthyl chiral scaffold and were doped into 5CB to construct N*LLC. As the concentration of the doped achiral naphthalimide derivative (NIA) increased, the CPL wavelength sequentially blue-shifted from red to yellow and then to green, the g_lum also increased to 0.3, which is fundamentally different from the conventional regulation with red-shifted chiral luminescence. Moreover, the introduction of trifluoroacetic acid enabled the emitted CPL was reversibly switched, allowing reversible control of wavelength and g_lum. Theoretical calculations revealed that, FRET-dominated process transforms into exciton coupling (EC)-governed interactions with the NIA concentration increased. This work demonstrates a feasible strategy of achieving reversible control of CPL within a single supramolecular system, offering new insight into the development of adaptable chiral photonic devices.