Enhanced NitrogenDioxide Detection Using Resistive Graphene-Based Electronic SensorsModified 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.