Designing Luminescent Liquid Crystals Using an AIE-Active Pseudopeptide Chiral Dopant: Circular Dichroism, Circularly Polarized Luminescence, and Photoluminescence Studies

Chiral helical assembly of luminophores with aggregation-induced emission (AIE) characteristics can efficiently enhance the chiroptical response. Liquid crystalline (LC) ordering states suitable for AIE and sensitive to chiral perturbations can lead to further enhancements. Herein, we report a general approach to induce chiral structure in LC using an AIE-active pseudopeptide chiral dopant. Activation of both circular dichroism (CD) and circularly polarized luminescence (CPL) signals in induced cholesteric (N*) phase demonstrates efficient chirality transfer and AIE phenomenon via pseudopeptide molecules. A control experiment was conducted using the smectic-A (SmA) phase LC lacking helical assembly with the same added dopant. Induced SmA* phase favors AIE enhancement, although no chiroptical response is observed. Electrically tunable fluorescence intensity is obtained based on the light scattering ability of N* helices varied among planar, focal-conic, and homeotropic states. The temperature sensitivity of fluorescence is also recorded in doped media. Our study demonstrates the simpler peptide molecules for doping in LC matrices to induce efficient chiroptical properties with tunable fluorescence. These doped LC systems can be successfully utilized for advancing display technologies.