Visible Light Rewritable and Long-Lived Colors in Cholesteric Liquid Crystals: A Facile Co-Doping Strategy

Photoresponsive cholesteric liquid crystals (CLCs) are able to selectively reflect colors upon light exposure. Yet, it still remains a formidable challenge to realize simultaneous rewriting and long-life color in CLCs using visible light. Herein, guided by time dependent density functional theory (TD-DFT) computation, an octafluorinated binaphthyl azobenzene is synthesized to achieve the fast response and long-life color upon visible light exposure. Subsequently, based on the solubility parameter, uniform CLCs are formulated through a facile co-doping strategy. Interestingly, the CLCs change reflection colors from blue to green, red, and then into the near infrared region in seconds upon 550 nm light illumination. The completely reversible process is readily accessable upon 450 nm irradiation. More importantly, each color is independently stable for similar to 24 h in the dark.