Polymeric interfacial engineering approach to perovskite-functionalized organic transistor-type gas sensors

Organic semiconductors (OSCs) are promising sensing materials for printed organic gas sensors. Although OSCs show promise since they are mechanically flexible, cost-effective, and lightweight, they still face challenges related to low sensitivity and poor stability under ambient conditions; their development therefore lags that of inorganic-based gas sensors. Functional nanomaterials can be incorporated into organic semiconductors to complement the gas sensitivity and stability. Herein, we describe the fabrication of novel organic–inorganic hybrid gas sensors via the blending of perovskite nanocrystals and conductive polymer. We introduced a perovskite-structured material, CsPbBr3, into a conductive polymer matrix, which substantially improved its gas-sensing performance while maintaining its high responsivity and response rates. To further improve the adsorption of target gas molecules, we modified the surface of the perovskite using a zwitterionic polymer subjected to a hydration treatment. The results demonstrate that the amide group of the encapsulation polymer exhibits high affinity toward NO2 gas molecules and that this affinity becomes more pronounced upon hydration of the polymer. We also demonstrate the perovskite materials in the semiconducting polymer layer can protect the polymer thin film against oxidation during prolonged storage under ambient conditions because of the perovskite crystals’ ability to adsorb oxidizing molecules.