Graphene foam pressure sensor based on fractal electrode with high sensitivity and wide linear range

Piezoresistive sensors based on three-dimensional graphene foams (GFs) can be used in health monitoring, electronic skin and wearable smart devices. It is still challenging to obtain sensors with high sensitivity and a wide linear range through a simple and an efficient method. In this paper, a graphene foam pressure sensor based on a fractal electrode (GFPSFE) is proposed. The GFPSFE contains a wave-structured GF (WSGF), a fractal electrode (FE), and a normal electrode. The FE regulates the contact resistance of the WSGF, improving the sensitivity and the linear range of the GFPSFE. We compared three GFPSFEs with different FEs, and investigated the influence of FEs on the sensitivity and the linear range of GFPSFEs. The GFPSFE with zigzag FE (Z-GFPSFE) has high sensitivity (134.75 kPa −1 ), wide linear range (0–35 kPa), fast response/recovery (83 ms and 166 ms), and excellent stability (2000 cycles). In addition, the sensor was attached to the human body to measure motions and pulse, demonstrating the potential application in the fields of health monitoring and human-machine interfaces.