Research Progress of 3D Printed Flexible Electronic Devices

Abstract

With its high design freedom, wide material compatibility, and versatile processes, 3D printing technology has emerged as a revolutionary approach to the fabrication of flexible electronic devices, and has been shown to have tremendous applications in smart wearables, healthcare monitoring systems and soft robots. But traditional planar production processes are incapable of producing flexible electronics with complex structures and multifunctional integration, which is driving the development of novel manufacturing processes. This review paper comprehensively reviews the research progress of 3D printing in flexible electronics from a process point of view. First, it explains the working principles and technical features of common processes such as direct ink writing, photopolymerization, inkjet printing and laser-based printing. Secondly, it offers specific discussion on the current research progress of different processes in typical applications including flexible sensors, energy devices and soft actuators. Thirdly, it discusses the latest trends such as multi-process integration and structure-sensing system integration. The research shows that various manufacturing processes exhibit specific characteristics in terms of resolution, material composition and speed, while multi-process integration is a way to address the challenges of single-process technologies. Finally, this paper provides a summary of current challenges and future directions such as multi-process integration, 4D printing, artificial intelligence (AI) innovation and roll-to-roll (R2R) mass production, to guide technical roadmaps and process choices for researchers in the field of flexible electronics.