From nano to macro: Light‐driven chiral dopants in liquid crystals

Abstract Harnessing nanoscale molecular structural changes to achieve precise control over macroscopic devices represents an emerging and effective strategy. One promising approach involves the introduction of light‐driven chiral dopants into liquid crystals (LCs), enabling the fine‐tuned modulation of the helical superstructures in cholesteric liquid crystals (CLCs) via photoisomerization. This strategy opens up exciting possibilities for the development of innovative photo‐responsive devices with dynamic functionalities. This review focuses on the most common light‐driven chiral dopants used in LCs, including azobenzene, diarylethene, α ‐cyanostilbene and overcrowded alkene. The chemical design principles of these four types of chiral switches are highlighted, along with their abilities to induce pitch changes and helical inversion in CLCs. Finally, the applications of light‐driven chiral dopants in controlling helical superstructures are showcased, particularly in display technologies, anti‐counterfeiting, optical modulation and 3D droplet manipulation. It is hoped that this review provides valuable insights and guidances for the development of novel light‐driven chiral dopants and the advancement of soft matter material applications.