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.