Fabrication of an ultra-sensitive humidity sensor based on polypyrrole flakes/β-AgVO ₃ nanowires nanocomposite films <i>via in situ</i> photopolymerization

An ultra-sensitive impedance-type humidity sensor was developed through <i>in situ</i> UV-irradiation photopolymerization of a polypyrrole flakes (PPy Fs)/β-AgVO₃ nanowires (NWs) nanocomposite film on an alumina substrate. The composition, microstructure, and morphology of the PPy Fs/β-AgVO₃ NWs nanocomposite films were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The influence of varying PPy Fs concentrations on the electrical properties and humidity-sensing performance of PPy Fs/β-AgVO₃ nanocomposite films was systematically investigated. A PPy Fs/β-AgVO₃ NWs nanocomposite film composed of 0.5 mL of PPy Fs and 0.1 g of β-AgVO₃ NWs exhibited a broad operating humidity range, exceptional sensitivity, satisfactory linearity, minimal hysteresis, rapid response/recovery time, and low temperature dependence. The humidity-sensing mechanism of the PPy Fs/β-AgVO₃ NWs nanocomposite film-based sensor was analyzed using complex impedance spectra.