High-Performance Flexible Strain Sensor Fabricated Using Laser Transmission Pyrolysis

In recent years, metal crack-based stretchable flexible strain sensors have attracted significant attention in wearable device applications due to their extremely high sensitivity. However, the tradeoff between sensitivity and detection range has been an intractable dilemma, severely limiting their practical applications. Herein, we propose a laser transmission pyrolysis (LTP) technology for fabricating high-performance flexible strain sensors based on (Au) metal cracks with the microchannel array on the polydimethylsiloxane (PDMS) surface. The fabricated flexible strain sensors exhibit high sensitivity [gauge factor (GF) of 2448], wide detection range (59% for tensile strain), precise strain resolution (0.1%), fast response and recovery times (69 and 141 ms), and robust durability (over 3000 cycles). In addition, experiment and simulation results reveal that introducing a microchannel array enables the stress redistribution strategy on the sensor surface, which significantly improves the sensing sensitivity compared to conventional flat surface sensors. Based on the excellent performance, the sensors are applied to detect subtle physiological signals, such as pulse and swallowing, as well as to monitor large-scale motion signals, such as knee flexion and finger bending, demonstrating their potential applications in health monitoring, human-machine interactions, and electronic skin.