Fig. 1. Schematic diagram of the fabrication process of the AgNWs IDE-rGO device.

Fig. 2. (a) Optical image of the AgNWs IDE array on portable stickers; (b) dimensions of the single electrode structure.

Fig. 3. Schematic illustration of the gas sensing test setup.

Fig. 4. Real-time response curves to 5–50 ppm NO₂.

Fig. 5. Plot of response vs. concentration.

Fig. 6. Plot of recovery vs. concentration.

Fig. 7. Repeatability of the sensor after exposure to 15 ppm NO₂.

Fig. 8. Response and recovery times of the sensor to 5 ppm NO₂.

Fig. 9. Selectivity of the sensor by exposing the device to different target gases.

Fig. 10. Flexibility of the AgNWs IDE-rGO sensor: (a) Device resistance varies with the bending cycles; (b) plot of response vs concentration at the different bending angles.