Inquest of highly sensitive, selective and stable ammonia (NH3) gas sensor: Structural, morphological and gas sensing properties of polyvinylpyrrolidone (PVP)/CuO nanocomposite

In the present work, highly selective, stable and room temperature operable sensor of copper oxide (CuO), polyvinylpyrrolidone (PVP) and PVP/CuO nanocomposites were successfully fabricated on interdigitated copper electrode by using drop casting method. The CuO and PVP/CuO nanocomposites were synthesized via simple chemical reduction and ultrasonication method, respectively. Structural, morphological and elemental characterization of the PVP/CuO nanocomposites were carried out through X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy techniques. Successful synthesis of the nanocomposites with amorphous and crystalline nature was confirmed by the above-mentioned techniques. Gas sensing properties of the PVP/CuO nanocomposites were studied using different wt % (1-8) of CuO in the PVP matrix through LCR meter. It was observed that the sensor with 8 wt% CuO content exhibited an excellent selectivity and reproducibility towards NH3 gas at room temperature. A capacitance response of 160 nF was recorded for 200 ppm concentration of NH3 gas. The PVP/CuO 8 wt % nanocomposite sensor also showed an excellent stability over a period of 90 days (less than 5 % variation) and has very short response and recovery time of 17 s and 15 s respectively.