A flexible, ultra-highly sensitive and stable capacitive pressure sensor with convex microarrays for motion and health monitoring

Recently, flexible sensors endowed with high sensitivity, low detection limit, broad working pressure range and fast response have aroused widespread concern owing to their vital role in the development of wearable artificial devices, human-machine interaction and healthcare systems. Herein, flexible and highly sensitive capacitive pressure sensors were fabricated based on flexible electrodes with convex microarrays and ultrathin dielectric layer. The proposed sensor is constructed by sandwiching a top micro-arrayed electrode, a middle ultrathin dielectric layer and a bottom micro-arrayed electrode, and it demonstrates an ultra-high sensitivity of 30.2 kPa−1 (0–130 Pa), fast response time of 25 ms, low detection limit of 0.7 Pa and extreme stability of 100 000 cycles without fatigue. The finite-element analysis indicates that the changes of contact area and distance between two electrodes under external stimulus are critical to achieve superior properties of the sensor. Benefitting from the outstanding comprehensive performance, the enormous potential ability of the capacitive sensor in monitoring physiological signals and robot hand grabbing motions have been successfully demonstrated, which indicates promising applications in wearable intelligent electronic devices.