Low Cost, Flexible, Room Temperature Gas Sensor: Polypyrrole-Modified Laser-Induced Graphene for Ammonia Detection

The electrochemical synthesis of polypyrrole (PPy) on laser-induced graphene (LIG) electrodes is investigated in this study, along with the gas-sensing applications of these modified laser-tailored materials. A simple and scalable method for the low-cost, large-scale production of PPy@LIG nanocomposites (PPy@LIG NCs) is proposed. This nanocomposite is subsequently applied to design chemoresistive flexible gas sensors to detect ammonia (NH3) levels at room temperature. Following a brief gas exposure, PPy@LIG NCs sensors demonstrate changes in resistance with a sensitivity 14 times higher than that of pure LIG. Moreover, excellent repeatability in results and a low detection limit of 1 ppm were achieved. The LIG formation and electrochemical synthesis of PPy were confirmed through Raman spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The analysis by field emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM) verified the formation of PPy@LIG NCs. In conclusion, this work introduces the novel PPy@LIG NCs and its application in gas sensing, showcasing their unique selectivity, enhanced sensitivity, and cost-effective production. These attributes mark a significant step forward, presenting new possibilities for the development of advanced gas-sensing systems aimed at improving air quality monitoring.