Novel flexible room temperature NO2 gas sensor based on polypyrrole coated SnO2 nanoparticles

In this paper, we demonstrate a novel flexible gas sensor based on polypyrrole (PPy) coated SnO₂ nanoparticles that can be employed to detect low concentrations of NO₂ (0.5-5 ppm) at room temperature. This low-cost, easy-fabrication and wearable gas sensor was fabricated on PET substrate. The sensitive film was formed by first drop casting the solution of SnO₂ nanoparticles and FeCl₃ on the as patterned interdigital electrodes on PET substrate; then the substrate was exposed to saturated pyrrole vapor for 3h to obtain PPy coated SnO₂ sensitive film. Our sensor shows good performance in detecting low concentration NO₂ and the estimated detection limit is about 100 ppb at room temperature.