Laser micro-structured pressure sensor with modulated sensitivity for electronic skins.

Micro-structured pressure sensors with broad pressure sensing range, high sensitivity and rapid response speeds are highly desired for epidermal electronic skin. The widely used methods to fabricate micro-structured pressure sensors are lithography and biomaterial-replicating, which are either complex in preparation procedure or uncontrollable in micro-structure morphology. In this work, laser micro-structured wearable pressure sensors with high-performance are developed for epidermal electronic skin. Laser micro-engineering, with scalability, high-efficiency, and controllability, is employed to prepare a series of micro-structures on elastomers for modulating and enhancing the sensitivity of the sensors. The device with micro-domes owns a sensitivity of -1.82 kPa-1, which is approximately 17 times better than the one based on long micro-ridges. Due to the reduced viscous properties of the elastomers by laser micro-engineering, the sensor based on micro-domes demonstrates rapid response/relaxation speeds of 0.036 and 0.052 s, respectively, and a detection limit of 0.001 kPa. Additionally, the device has a good durability (6,000 cycles) with a repeatability deviation of 1.44%, confirming its stability. Combined with near field communication technology, the sensor has been investigated as epidermal electronic skin for health monitoring.