Graphene Aerogel‐Based Pressure Sensors with Gradient Structure for Subtle Physiological Signals and Motion Monitoring

Abstract High‐performance flexible wearable pressure sensors require the simple preparation method coupled with a well‐designed structure. Graphene aerogel has garnered significant attention as a flexible pressure sensor due to its exceptional features such as high porosity, favorable compressibility, and fine conductivity. However, it remains challenging to precisely control the 3D structure of the graphene aerogel within the sensors, which limits the detection sensitivity and application range. Here, a freeze‐assisted transfer printing strategy (FATPS) is proposed for fabricating a high‐performance graphene aerogel‐based sensor with the gradient structures. Compared to sensors prepared using mold methods, the sensitivity of the sensor produced through FATPS can be enhanced by nearly tenfold. Furthermore, the gradient structure empowers the graphene pressure sensor with excellent reliability and rapid response time (50 ms) within the pressure range of 0.1–50 kPa. The sensor exhibits the capability to monitor and recognize various physiological activities, including pulse, vocalization, coughing, swallowing, and finger bending. It is expected that the sensor has remarkable potential applications in medical diagnosis, disability aid, and athletic injury prevention and so on.