Colorimetric sensing of chloride in sweat based on fluorescence wavelength shift via halide exchange of CsPbBr3 perovskite nanocrystals

Abstract Considering the high importance of the rapid detection of chloride ion (Cl − ) in sweat for the diagnosis of fibrotic cysts, we have investigated the heterogeneous halide exchange between CsPbBr 3 perovskite nanocrystals (PNCs) in n -hexane and Cl − in aqueous solution. The results show that CsPbBr 3 PNCs could achieve fast halide exchange with Cl − in the aqueous phase under magnetic stirring at pH = 1, accompanied by a significant wavelength blue shift and vivid fluorescence color changes from green to blue. Therefore, a fluorescence wavelength shift-based colorimetric sensing of Cl − based on the halide exchange of CsPbBr 3 PNCs has been developed to realize the rapid detection of Cl − in sweat. Compared with the conventional fluorescence intensity-based method, this method is of high convenience since the whole procedure could be achieved within 5 min without any sample pretreatment (even no dilution), demonstrating promising application prospects. Fluorescence wavelength-shift based colorimetric sensing of chloride in sweat via halide exchange of CsPbBr 3 perovskite nanocrystals