Performance of a fabricated nanocomposite-based capacitive gas sensor at room temperature

In this research, we synthesized a nanocomposite based on pyrrole-bromoaluminum phthalocyanine materials and proposed an interdigitated capacitive electrode for H₂S gas sensing. In this framework, we devoted particular attention to AC electrical measurements of the device on exposure to gas rather than resistance measurement. Nanostructured thin films of the nanocomposite were prepared on precoated interdigitated aluminum electrodes using electron-beam evaporation technique, which were characterized using field emission scanning electron microscopy (FESEM). FESEM micrographs show films are uniform with densely packed nanoparticles. The AC electrical measurements were performed in 1, 10 and 100 kHz frequency at room temperature. Since the best sensor response was achieved for 1 kHz frequency, we limited the analysis to that Frequency. Gas sensing performance of the nanocomposite device results in fast response and good stability over the first 2 months to 100 ppm H₂S gas by monitoring the changes in capacitance at the 1 kHz frequency. It produces 61% and 28% of the first response after 2 and 4 months, respectively which indicating lack of long-term stability. Our results show that the fabricated nanocomposite-based capacitive gas sensor may be used as a disposable sensing device by means of a simple and cost-effective construction method.