Flexible Interfacial Capacitive Pressure Sensor Based on Randomly Distributed Micro-Pits Electrode

Pressure sensors are regarded as an important part of flexible electronic devices. However, the sensitivity of capacitive pressure sensors is relatively low to obtain distinct and stable signals along with a high signal-to-noise ratio. Interfacial capacitive pressure sensor, which has a large initial capacitance due to the formation of an electric double layer, is more resistant to interference. Herein, the deformation of the micro-pits structure in electrode under external stimulus is proved to be helpful for improving the performance of the pressure sensor. Using sandpaper as a random microstructure transfer template, an interfacial capacitive pressure sensor based on random micro-pit structure carbon electrodes was prepared. The electrical performance of the electrode is inferred to be an important factor in achieving excellent properties. The proposed device exhibits long-term durability over 8000 cycles, low detection of a limit of 1.7 Pa, and a fast response time of ~30 ms. The applications of these pressure sensors in sensing pulses, acoustic vibration, and human motion are demonstrated, exhibiting their great potential use in healthcare monitoring, motion detection, and tactile sensing.