Reusable gasochromic gas sensor with enhanced selectivity for acidic gases via surface-engineered all-inorganic perovskite nanocrystals

The use of strong acids is crucial for the fabrication of highly integrated semiconductor devices. To effectively detect and alert against the potential hazards of acid gas leakage, considerable advancements have been made to enhance gas sensor sensitivity. However, most available gas sensors only detect cations (H⁺), making it challenging to precisely identify the specific types of acids present. Cesium lead halide perovskite nanocrystals, renowned for their exceptional optical properties, have emerged as promising candidates for gas-sensing applications. Nonetheless, concerns regarding reuse stability persist. In this study, surface engineering via solution-phase ligand exchange is conducted to address halide vacancies and prevent acid-induced structural degradation. The resulting surface-modified perovskites exhibit remarkable gasochromic sensitivity and selectivity towards HCl and HNO₃. Furthermore, the vivid emission properties of these perovskites enable the visual detection of danger without the need for additional warning equipment. Finally, the reusability of the gas sensors is evaluated, and the perovskite-based sensors are recyclable.