Programmable Stimulation and Actuation in Flexible and Stretchable Electronics

Flexible and stretchable electronics represent a rapidly growing class of microsystem technologies that are revolutionizing human lives with pioneering applications in digital healthcare, personalized medicine, human–machine interface, and Internet of Things, among others. As an important aspect of smart devices, the on‐demand output capability of flexible/stretchable electronic devices, characterized by stimulation or actuation, enables active feedback and interaction to form a closed‐loop system, in combination with versatile sensing capabilities. This review summarizes some of the most important progresses on the stimulating/actuating capabilities (e.g., electrical, thermal, mechanical, optical, and chemical stimulation) of flexible/stretchable electronics, covering different mechanisms of stimulation and actuation, as well as diverse venues of applications. The stimulating/actuating capabilities in flexible/stretchable electronics play crucial roles in driving both fundamental and applied advances in research, such as medical measurement, biological study, medical therapy, and human–machine interface. Most of the existing flexible/stretchable systems use functional components to fulfill the demand of stimulation and/or actuation, with intricate strategies for system integration. Sustained advances in mechanics design concepts and high‐performance materials are the key to ensuring the evolution of flexible/stretchable electronics with enhanced stimulation and actuation capabilities. Finally, outlooks on the remaining challenges and open opportunities are provided.