Amplified Circularly Polarized Luminescence of Chiral AIE-active Tetraphenylbutadiene Derivatives in Nematic Liquid Crystal

Circularly polarized luminescent (CPL) materials featuring high luminescence dissymmetry factors (g_lum), high photoluminescence quantum yields (Φ_PL), and tunable emission properties are essential for practical applications. Herein, three chiral aggregation-induced emission (AIE) tetraphenylbutadiene (TPB) derivatives (TPB-Chol^*-H, TPB-Chol^*-CHO, TPB-Chol^*-OC₆) with high Φ_PL were synthesized, each bearing symmetric chiral bis-cholesteryl moieties and different electron-donating/accepting groups. When employed as chiral dopants, minute quantities of each derivative were individually doped into the achiral nematic liquid crystal (LC) 5CB, affording three series of luminescent chiral nematic LC composite systems (TPB-N^*-LCs). These composites exhibit remarkable CPL activity with high g_lum values, attributed to host-guest interactions that facilitate co-assembly into ordered supramolecular helices and chiral amplification, despite the chiral AIE dopant itself lacking CPL emission. CPL signals and g_lum values enhance with increasing chiral dopant loading, peaking at +0.31, +0.42, and +0.58 for TPB-Chol^*-H/5CB, TPB-Chol^*-CHO/5CB, and TPB-Chol^*-OC₆/5CB, respectively, at 3 wt% doping. Notably, the introduction of electron-donating hexyloxy groups (TPB-Chol^*-OC₆) or electron-accepting aldehyde groups (TPB-Chol^*-CHO) modulates molecular packing, compatibility with 5CB host, and intermolecular interactions. Doping TPB-Chol^*-OC₆ into 5CB achieves the optimal performance, with g_{lum =} +0.58 and Φ_PL = 84.5%. This work offers an effective strategy for developing CPL materials with simultaneously high g_lum and Φ_PL.