The next step was the fabrication of the sensor using GO as the humidity sensing material,
in which drop-casting was adopted.
In brief, a drop of GO dispersion (50 ml, 1.08 mg/ml, dissolved in ethanol) was dropped onto the interdigitated electrodes through a pipette, followed by drying under a temperature 45 °C for 1 h.
To more comprehensively examine the sensing performance of the sensor, we characterized the interdigital electrodes by scanning electron microscopy (SEM) after being covered with GO films.
As shown in Fig. 6, the interdigitated electrode exhibits abundant wrinkles, demonstrating complete coverage with the GO films.