Highly efficient and cost-effective polyaniline-based ammonia sensor on the biodegradable paper substrate at room temperature

A highly efficient, flexible and cost-effective ammonia (NH3) gas sensor is developed on a biodegradable paper substrate. The polyaniline (PANI) film as an active sensing material was deposited by a simple in-situ polymerization method and optimized for NH3 detection. The PANI film was investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) for structural and morphological properties. The sensor was tested for its efficiency to detect the NH3 gas over the concentration range of 12–1000 ppm at room temperature. The sensor showed excellent repeatability, stability and selectivity towards NH3 detection. At concentrations of 12 ppm (lower level), 200 ppm (intermediate level), and 1000 ppm (higher level), the sensor exhibited effective response values of 3.60, 6.85, and 9.33, respectively. The sensor exhibited a quick response time of 30–9 s when subjected to 12–1000 ppm of NH3. The sensor can detect ammonia gas in real-time, which makes it useful for identifying rapid changes in NH3 concentration. The sensor response was reduced by 5.5% towards 200 ppm NH3 despite a significant variation in relative humidity from 20% to 80%. Based on these results, our flexible PANI sensor is a viable option for efficient and cost-effective on-site NH3 detection.