A 3D-printing approach toward flexible piezoelectronics with function diversity

The flexible electronics is a fast-moving, emerging interdisciplinary research that involves the use of organic/inorganic functional materials, electronic component designs, and their integration fabrication. Here, we review recent advancements in flexible piezoelectronics and 3D printing preparation, including (i) flexible piezoelectric materials suitable for 3D printing, their piezoelectric properties, and a comparison among them, (ii) 3D-printed flexible piezoelectronics with increasing capabilities in sensing, energy harvesting, and electronic display, and (iii) 3D printing technology and preparation methods, such as inkjet printing, thermal or laser-assisted direct writing printing (DIW), and fused deposition molding (FDM), which enable rapid design and manufacture of new flexible electronic devices. We also summarize the design methods of flexible piezoelectric devices based on 3D printing technology, and discuss their extensive applications in smart wearable electronics, flexible circuits, the Internet of Things, and software robots. Flexible piezoelectronics is a rapidly advancing field that is poised to have a significant impact on the modern industrial structure and human life. Finally, we prospect for the future development of 3D printing flexible piezoelectronics and the challenges that researchers may encounter.