Tunable wrinkled graphene foams for highly reliable piezoresistive sensor

The rapid development of flexible electronics and artificial intelligence brings an urgent demand for high-performance flexible pressure sensors. In this paper, a method is proposed to prepare wrinkled graphene foam by freeze-drying and post-annealing method, where zinc chloride is used to tune structure. A piezoresistive pressure sensor based on the wrinkled graphene foam is assembled. Benefiting from the unique contact interface of wrinkled microstructures, as well as the mechanical strength and the superior resilience of the foam structure, the piezoresistive pressure sensor exhibits a reliable stability (>105 cycles), short response time(150 ms)and low relaxation time (120 ms). And it also demonstrates good performances in various applications, such as pulse detection, voice recognition as well as the finger joints movement. It is suggested that the pressure sensor based on wrinkled graphene foam has great potential in flexible electronics to achieve health monitoring and motion detection. It also paves the way for other wrinkled materials to be involved in the fabrication of pressure sensors.