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

Circularly polarized luminescent (CPL) materials featuring high luminescence dissymmetry factors (glum), high photoluminescence quantum yields (ΦPL), 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 ΦPL 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 glum 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 glum 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 glum = +0.58 and ΦPL = 84.5%. This work offers an effective strategy for developing CPL materials with simultaneously high glum and ΦPL.