Fig. 6: Flexible humidity sensors using CNTs as humidity-sensitive materials.

a A humidity sensor constructed based on a cellulose paper substrate, its sensing mechanism, and the response and recovery curves when the humidity changes between 10-60% RH⁸¹. Copyright © 2012, American Chemical Society. b The schematic diagram of the sensing mechanism of the humidity sensor using CNT/PVP as the humidity-sensitive material, the response and recovery times of the sensor in the range of 10-96% RH, and the resistance changes of the CNT/PVP-based humidity sensor on the palm during handshakes⁸². Copyright © 2023, American Chemical Society. c The fabrication process of the flexible humidity sensor using CNCs/CNT as the humidity-sensitive material, as well as its application in non-contact humidity detection around the fingertip⁸³. Copyright © 2022, Royal Society of Chemistry. d The working principle and applications of flexible humidity sensors, and the response times of the sensor when the airflow humidity is 90% RH and 0% RH, respectively⁸⁴. Copyright © 2023, American Chemical Society