Multi-color tunable circularly polarized luminescence in one single AIE system

Abstract

Circularly polarized luminescence (CPL) materials with a large luminescence dissymmetry factor (<i>g</i> _lum) and multi-color properties are very attractive. While multi-color tunable CPL can be realized by different organic dyes, the challenge of realizing both a higher <i>g</i> _lum and multiple colors using a single component remains. Here, we design an aggregation-induced emission (AIE) fluorophore, which is a pyridine functionalized cyanostilbene attached to a chiral unit, and realize multi-color tunable CPL with a high <i>g</i> _lum. The compound can self-assemble into a nanohelix and form both gel and xerogel films, exhibiting blue CPL with large <i>g</i> _lum values of -3.0 × 10^-2 and -1.7 × 10^-2, respectively. With the assistance of pyridine protonation, the xerogel films exhibit red-shifted CPL signals from 480 nm to 530 nm, covering from blue <i>via</i> green and yellow to orange. Additionally, the <i>g</i> _lum remains constant during the process. This work paves a simple and convenient way to construct multi-color tunable CPL materials using a single molecule.