Fig. 4. Evaluation of the durability and performance of FGO- and rGO-based sensors for monitoring the resistance variation under exposure to NO2. (a) Bending test of gas sensors based on FGO and rGO nanosheets on yarn fiber. (b) The resistance variation of fiber-type sensors based on FGO and rGO according to the number of bending cycles (bending radius = 0.2 mm). The inset image is a yarn-based device sewed in different letters on a woven fabric. (c) Real-time monitoring of resistance of sensors based on FGO with HFBA and rGO during the bending test under various bending conditions. (d) Time-dependent electrical response of gas sensors based on FGO and rGO nanosheets after 104 cycles of bending test under exposure to 0.15 ppm NO2 at the bias voltage (VDS) = 0.1 V. (e) Gas response of FGO- and rGO-based gas sensors as a function of the number of bending cycles (bending radius = 0.2 mm).
