Ultrahigh-Response Humidity Sensor Arrays Based on a Graphene/Polymer Composite for Contactless Gesture Monitoring

Flexible humidity sensors have attracted widespread attention for their potential applications in telemedicine, motion detection, etc. Compared with conventional humidity sensors, flexible humidity sensors have advantages in flexibility, integration, and portability. However, reported flexible humidity sensors usually suffer from a low response, complex manufacturing processes, and poor stability. We fabricate a humidity sensor using a graphene/polymer composite as the sensitive material with a focus on improving the response and simplifying the manufacturing process. Then, we optimize the performance of the prepared flexible sensor by component design. The prepared flexible humidity sensor has a response of 1123%, and response and recovery times of 61.1/92.0 s, respectively, showing excellent humidity sensing performance. The human respiration, skin humidity field, and environmental humidity detection applications are successfully realized by the humidity sensor. Besides, the contactless gesture monitoring is accomplished by the humidity sensor array, demonstrating the potential for further development into healthcare and contactless human–machine interaction.