Visualized Fluorescence Sensor for Dichloromethane Based on Photochromic Perovskite Nanocrystals

Dichloromethane (DCM), which is a widely used organic solvent in industrial production, is currently classified as a Class 2A carcinogen. Considering its potential harm to human health, it is necessary to design a convenient and economical method to monitor the concentration of DCM in the environment in real time. Here, we present a visualized fluorescence sensor for DCM utilizing photochromic CsPbBr3 perovskite nanocrystals (PNCs). By measuring the amount of chloride ions dissociated from DCM under 365 nm UV light catalysis, the resulting ion exchange products of CsPbBr3–xClx exhibit distinct fluorescence colors based on the halogen ratio, enabling visual detection. In addition, we have observed a linear relationship between the concentration of DCM and the wavelength shift difference of PNCs after a 30 min 365 nm UV exposure, within the DCM concentration range of 1–20% (0.16–3.11 mM). And the limit of detection was calculated to be 0.29%. We have successfully utilized this sensor to detect the concentration of DCM in laboratory waste liquid, achieving a high recovery rate. This application is beneficial for long-term laboratory personnel to promptly identify the source of harmful gases, thereby significantly contributing to the maintenance of laboratory safety and physical health.