Electrical conductivity based ammonia, methanol and acetone vapour sensing studies on newly synthesized polythiophene/molybdenum oxide nanocomposite

Polythiophene (PTh) and polythiophene/molybdenum oxide nanocomposites (PTh/MoO3) were synthesized by an in-situ chemical oxidative method. The successful synthesis of both the materials was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal stability of the materials was examined in terms of conductivity retention under isothermal and cyclic aging conditions. PTh/MoO3 showed much greater conductivity retention (i.e., thermal stability) than pristine PTh under both conditions. PTh/MoO3 showed 18.22 times greater electrical conductivity than pristine PTh at room temperature. The sensing properties of PTh and PTh/MoO3 were tested against ammonia, methanol, and acetone vapour at room temperature. The percent sensing response (%) of the PTh/MoO3 sensor was found to be about 1.64, 1.44, and 1.48 times greater than the PTh sensor towards ammonia, methanol, and acetone at 1 M, respectively. The PTh/MoO3 sensor showed 1.48, 1.60, and 1.72 times greater reproducibility than the PTh-based sensor towards ammonia, methanol, and acetone, respectively. Thus, at a 1 M concentration of ammonia, methanol, and acetone, the PTh/MoO3 sensor performed much better than the PTh sensor in terms of the sensing response and reproducibility. Furthermore, the PTh/MoO3 sensor showed a maximum and minimum sensing response towards ammonia and acetone, respectively.