Optimization of microstructure design for enhanced sensing performance in flexible piezoresistive sensors

Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health, as well as in robotics, prosthetics, and human-computer interaction interfaces. Among the various flexible sensor types, those with microstructure designs are considered promising for strain sensing due to their simple structure, high sensitivity, extensive operational range, rapid response time, and robust stability. This review provides a concise overview of recent advancements in flexible piezoresistive sensors based on microstructure design for enhanced strain sensing performance, including the impact of microstructure on sensing mechanisms, classification of microstructure designs, fabrication methods, and practical applications. Initially, the review delves into the analysis of piezoresistive sensors' sensing mechanisms and performance parameters, exploring the relationship between microstructure design and performance enhancement. Subsequently, an in-depth discussion is presented, focusing on the primary themes of microstructure design classification, process selection, performance characteristics, and specific applications. The review employs mathematical modeling and hierarchical analysis to emphasize the directionality of different microstructures on performance enhancement and to highlight the performance advantages and applicable features of various microstructure types. In conclusion, the review examines the multifunctionality of flexible piezoresistive sensors based on microstructure design and addresses the challenges that still need to be overcome and improved, such as achieving a wide range of stretchability, high sensitivity, and robust stability. The review summarizes the research direction for enhancing sensing performance through microstructure design, aiming to assist in the advancement of flexible piezoresistive sensors.