Figure 3.

Humidity-sensing properties. (a) Current-voltage characteristics under different RH with an applied bias voltage fixed at 1 V (n = 3 measurements). (b) Sensitivity plots of flexible sensors under 65%RH-95%RH conditions. (c) Dynamic current change (1 cycle) of flexible sensors at 85%RH. (d) The humidity switching characteristic of the device at 95%RH. (e) Schematic diagram of humidity monitoring through exercise-induced respiration rate change. (f) Illustration of the sensing platform for real-time detecting, signal processing, and wireless transmission. (g) Measured respiration rate changes during the exercise experiment. (h) Real-time monitoring of humidity in mobile phone software from low humidity to high humidity. (i) Optical image of flexible humidity sensors. Scale bar: 1 cm. (j) Dynamic sensing curves of the flexible sensor under flat and bend state for 85%RH. (k) Long-term stability of the flexible sensor with 65%, 75%, 85%, and 95%RHs under 120 bending cycles.