Juan Shao, Yongxin Chang,*, Hao Wang, Haijuan Qin, Qiongya Li, Ting Yang, Mingliang Tang, Guoxiong Wang, Shuai Chen* and Guangyan Qing*

Small, 2025, DOI: 10.1002/smll.202502383

https://onlinelibrary.wiley.com/doi/10.1002/smll.202502383

   Pursuing innovative modulation strategies and high asymmetry factors (glum) remains a cornerstone in developing circularly polarized luminescence (CPL) materials. Traditional approaches primarily rely on two strategies: the bottom-up self-assembly of chiral small molecules, and the top-down co-assembly of achiral luminophores with supramolecular chiral templates (e.g., cellulose nanocrystals (CNCs), liquid crystals). These templates inherently possess pre-engineered or naturally ordered structures, serving as 'molds' or 'scaffolds' to embed and align achiral luminescent molecules within their chiral environments. However, the co-assembly of chiral small molecules with supramolecular templates remains underexplored, hindered by intricate preparation protocols and limited control over assembly behaviors. This issue raises compelling questions about chirality, particularly the interplay and compatibility of chiral components at the supramolecular level. Here we report the co-assembly and interplay between chiral aggregation-induced emission (AIE) molecules–PN-Phe halide and CNCs. Our findings indicate that halide ions, including F–, Cl–, Br–, and PF6–, significantly modulate the self-assembly behaviors of PN-Phe, resulting in notable differences in assembly morphologies, packing patterns, chiral signals, fluorescent quantum yields (QY), and lifetimes. Notably, PN-Phe-Cl– exhibits the highest glum value of −4.1 × 10−3, while PN-Phe-F– shows the lowest at −4.7 × 10−4. Interestingly, when these halide salts co-assemble with CNCs to form composite films, we observe a reversal in their glum values: the CNC-PVA-PN-Phe-Br– (CPP-Br–) composite film displays the highest glum value of −0.43, contrasting sharply with the low glum value of −3.1 × 10−2 for the CPP-Cl– film. The multiple color variations and potential application in anti-counterfeiting demonstrate the advantages of this co-assembly strategy. This work highlights the significant role of assembly patterns in constructing advanced CPL materials, revealing that halide ions could serve as effective modulators for CPL.