Bio-inspired multifunctional flexible visual sensors based on structural color materials

With the development of smart materials, flexible sensors are becoming increasingly critical in many fields such as physiological monitoring and medical diagnostics. Conventional flexible sensors predominantly depend on cumbersome electronic equipment to exhibit and document signals, yet they fail to provide an intuitive visualization of data, which severely impedes their utility and advancement in cutting-edge domains, including human–computer interaction, intelligent interface design, and visual sensing. In recent years, inspired by the chameleon skin, researchers have been committed to the study of flexible sensors with visual interaction capabilities, which can directly visualize the response to the stimulus location through the color change observable with the naked eye. Herein, this review summarizes the prevalent methods for fabricating visually responsive materials with structural color, meanwhile exploring how these materials can be functionally incorporated into flexible sensors to facilitate the monitoring of human movement, physiological health and external environment. Notably, this paper deliberates on the latest research advancements of optoelectronic dual-signal response and multifunctionalized flexible vision sensors, and emphasizes the challenges and great potential for future advances in flexible vision sensing technology, pointing the way to the development of advanced multifunctional sensors.