Enhanced nitrogen dioxide detection using resistive graphene-based electronic sensors modified with polymers of intrinsic microporosity

In this study, we report on the fabrication and evaluation of gas sensing performance for 3 × 3 graphene pixel array sensors coated with polymers of intrinsic microporosity (PIM-1 and PIM-EA-TB) and Matrimid, a commercial polyimide, for the detection of nitrogen dioxide (NO2). The polymer films, with thicknesses of only 9-11 nm, significantly enhanced the gas sensing performance, demonstrating responses as high as −25.7% compared to a bare graphene response of −10.8%. The gas sensing performance was evaluated in real-time by exposing the sensors to NO2 concentrations from 1 to 50 ppm, along with selectivity tests using ammonia (NH3), nitric oxide (NO), methane (CH4), and carbon dioxide (CO2). In addition to their high sensitivity, the sensors exhibited reduced response times by 56 s. They also demonstrated high selectivity for NO2, with minimal cross-sensitivity to other gases. Furthermore, the polymer membranes exhibited rapid recovery times (114-153 s) and limits of detection in the low parts per billion range, with PIM-EA-TB achieving a detection limit of 0.7 ppb. These features highlight their potential as promising candidates for real-time environmental monitoring of toxic gases, showcasing the potential use of PIMs to enhance the sensitivity and selectivity of graphene-based gas sensors and providing a foundation for further development of cost-effective and reliable NO2 detection systems.