Real-time gas sensors that are ultra-sensitive, highly selective, and capable of fast response/recovery are highly in demand for environmental and health monitoring; however, advances in such gas sensors have been limited. Here we report a flexible and transparent sub-ppb gas detection film fabricated by in situ electrochemical oxidative polymerization on single-layer graphene (SLG). As polypyrrole molecules are uniformly formed with flat orientations on SLG, the resulting sensor film exhibits excellent sensitivity and selectivity with nearly perfect reversibility without heat treatment or light irradiation. The sensing mechanism is well explained by molecular interactions between the sensing material and the gas molecular species. The sensor exhibits a detection limit as low as 0.03 ppb NO₂ and 0.04 ppb NH₃ at room temperature and operates well, even at 70 °C, showing feasibility for wearable applications in high-precision gas sensing.

中文翻译：

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基于单层石墨烯上排列良好的扁平聚吡咯的超灵敏，灵活，透明的气体检测膜†

对环境和健康监测的需求极高的实时气体传感器具有超灵敏性，高度选择性和快速响应/恢复能力。但是，这种气体传感器的发展受到限制。在这里，我们报告了一种通过在单层石墨烯（SLG）上进行原位电化学氧化聚合而制备的柔性且透明的亚ppb气体检测膜。由于聚吡咯分子在SLG上以平整的取向均匀形成，因此所得的传感器膜具有出色的灵敏度和选择性，几乎无需逆转即可进行任何热处理或光照射。传感材料和气体分子种类之间的分子相互作用很好地解释了传感机理。该传感器的检出限低至0.03 ppb NO ₂在室温下为0.04 ppb NH ₃，即使在70°C的条件下也能很好地运行，显示了在高精度气体传感中可穿戴应用的可行性。