The room temperature gas sensor based on Polyaniline@flower-like WO3 nanocomposites and flexible PET substrate for NH3 detection

The Polyaniline (PANI)@flower-like tungsten oxide (WO3) nanocomposites with different mole percentages of flower-like WO3 (2-50%) were successfully synthesized by using a facile in situ chemical oxidation polymerization method and were loaded on flexible polyethylene terephthalate (PET) substrate to fabricate NH3 sensors operating at room temperature. The morphology, nanostructures and thermal degradation behavior of the as-obtained sensing materials were measured and characterized utilizing SEM, TEM, FTIR, XRD and TG. Gas-sensing performances of fabricated sensors were tested and results indicated that the sensor with PANI@10 mol% flower-like WO3 exhibited the highest response value at approximately 20.1-100 ppm NH3 at room temperature, which is more than 6 times higher than that of pure PANI. Notably, the lowest detection limit of 500 ppb to NH3 was obtained at room temperature. Furthermore, the present sensor also showed rapid response and recovery rates of 13 s and 49 s, good repeatability, selectivity, and slight humidity effects to 10 ppm NH3 at room temperature. Moreover, the gas sensing mechanisms of PANI and nanocomposites were also discussed in detail. The enhanced sensing characteristics of nanocomposites were related to the morphology structure and p-n heterojuction between PANI and flower-like WO3.