Hybrid polyaniline-WO3 flexible sensor: A room temperature competence towards NH3 gas

In present study, a flexible, room temperature operable, and selective ammonia (NH3) sensor based on polyaniline and tungsten oxide (PAni-WO3) hybrid nanocomposite was successfully developed on polyethylene terephthalate (PET) substrate by in-situ chemical oxidative polymerization process and reported. Structural elucidation, surface morphology, and materials composition of flexible PAni-WO3 hybrid nanocomposites was analyzed systematically through X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, respectively. Gas sensing properties of flexible PAni-WO3 hybrid sensors was studied thoroughly and compared with pristine PAni and WO3 sensors. It was observed that the flexible sensor with 50 wt% WO3 content showed an excellent selectivity towards NH3 gas at room temperature along with 121% response towards 100 ppm. As-fabricated PAni-WO3 hybrid flexible sensors are capable to detect 1 ppm concentration of NH3 (Response = 9%) along with excellent stability and response reproducibility. Impedance spectroscopy was employed to quantify the gas sensing behavior of flexible PAni-WO3 sensor in presence of target gases and fresh air and resulting plots are simulated by equivalent circuits. Based on impedance results, the gas sensing mechanism of flexible PAni-WO3 nanocomposites in presence of NH3 atmosphere is described.