Conformation-Driven Circularly Polarized Luminescence Amplification in Intrinsically Chiral Main-Chain Polymers via Liquid Crystalline Self-Assembly

Abstract

Intrinsically chiral polymers are ideal candidates to fabricate high-performance circularly polarized luminescence (CPL) materials, as they circumvent the poor compatibility and phase separation in doped CPL systems. Nevertheless, their practical utility is hindered by low luminescence dissymmetry factors (glum), and the mechanism governing chiral amplification remains unclear. Herein, we report an unprecedented CPL amplification behavior in intrinsically chiral binaphthyl-based polymers, achieved via backbone conformational regulation rather than traditional modifications of axial chiral dihedral angles or monomer structures. Varying the binaphthyl substitution positions alone alters the polymer backbone geometries and assembly behaviors. Specifically, the linear backbone conformation of S/R-BF-2 drives long-range liquid-crystalline order and self-assembles into regular helical nanofibers, leading to prominent CPL with a high glum value of –0.15/+0.14. In contrast, S/R-BF-1 and S/R-BF-3, with distorted backbone conformations, exhibit disordered aggregates and negligible CPL signals. This work provides an alternative to conventional approaches for tuning intrinsically chiral polymers, offering a new strategy for the precise regulation of CPL signals.