Designing and development of polyvinylpyrrolidone-tungsten trioxide (PVP-WO3) nanocomposite conducting film for highly sensitive, stable, and room temperature humidity sensing

In the present research work, highly sensitive, stable, capacitive type humidity sensor based on polyvinylpyrrolidone and tungsten trioxide (PVP/WO3) nanocomposite was successfully developed. The sensing materials were prepared by using simple ultrasonication method and were characterized systematically through Fourier transform infrared spectroscopy, X-ray diffraction, high resolution transmission electron microscopy. Drop casting technique was used to develop sensing device using interdigitated copper electrode. Humidity sensing properties of PVP/WO3 nanocomposite sensors were investigated thoroughly and compared with pure PVP and WO3 sensors. It was observed that the humidity sensor with 20 wt% WO3 content showed high response of 44.73 nF/%RH, short response (10 s) and recovery time (15 s) as compared to pristine PVP and WO3 sensor. Low hysteresis value of 1.3 % was observed for PVP/WO3 20 wt% nanocomposite sensor along with excellent stability and repeatability.