Stimuli‐Responsive Afterglow from Luminescent Liquid Crystal Elastomers

Abstract

Stimuli-responsive luminescent polymeric materials which combine afterglow emission with mechanical flexibility and adaptability to external stimuli are well-suited for dynamic optical devices, encoding, anticounterfeiting, and soft robotics. However, current systems rely on static matrices and organic phosphors, which limit their afterglow duration, flexibility, processability, and responsiveness to various stimuli. Here, an active glow luminescent system for encoding, signaling, and tracking in dark environments by integrating inorganic ultralong afterglow phosphors with adaptive liquid crystal elastomer actuators is demonstrated. The resulting material exhibits ultralong emission (up to 1200 s) in the dark, enabling reprogrammable information encryption and reversible scattering-to-transparent transition upon mechanical, thermal, or light stimuli, allowing for multimodal decoding. A bicolor, spatially encoded phosphorescent soft actuator is fabricated that appears plain and unmarked under daylight, but reveals structured emission in the dark while simultaneously exhibiting shape change under heat or light. Incorporation of an additional fluorescent dye further endows the system with light-environment sensitivity, enabling luminescent rolling wheels and fiber actuators capable of self-signaling and recovery tracking. This work not only demonstrates constructing active luminescent materials but also provides valuable insights toward adaptive and interactive glowing optical devices.