Clear Disclosure of Hierarchical Chirality Transfer Mechanism and Wide Full-Color and White-Light CPL Emissions with Both High g_(lum) and Intensity by TPE Helicates

摘要

Chirality transfer and amplification play key role on research of chiral materials,but it is still a challenge to clearly disclose the chirality transfer mechanism.Here, tetraphenylethylene helicate (TPEH) with aggregation-inducedemission enhancement effect is doped into achiral nematic liquid crystal(NLC) to furnish a system of excellent chirality transfer and amplification forthe first time. It is found that left-handed helical (M) TPEH molecule withfour phenyl rings sloping right-down makes a staggered overlap with otherM-TPEH at right-up direction for attenuating the repulsive force betweenphenyl rings, which is further overlapped into a right-handed helix (P) andthen drives NLC array layers to the P-LC phase. Consequently, M-TPEHmolecule leads to P-LC phase, while P-TPEH arouses M-LC phase. Remarkably,this chirality transfer can amplify the circularly polarized luminescence(CPL) of TPEH by 100-fold and give a large absolute CPL dissymmetric factor(g_(lum)) of 0.21. Moreover, the chirality can be even transferred to other achiralfluorescence dyes, and both high absolute glum of up to 0.37 and high fluorescencequantum yield (Φ_f) of 92% are obtained. Consequently, a customizedwide full-color and white-light CPL emission from violet to near infraredwhich is closer to natural light is obtained.