Carbon dots-based dual-emission proportional fluorescence sensor for ultra-sensitive visual detection of mercury ions in natural water

Carbon dots (CDs) have become a hot topic in fluorescence sensing and bioimaging due to their superior optical properties, high sensitivity, and high selectivity for specific ubstances. In this experiment, a novel carbon quantum dot/copper nanocluster dual fluorescence emission composite (CQDs@SiO2/CuNCs) based on silica coating was constructed by a composite of CQDs@SiO2 and DPA-CuNCs, which can detect Hg2+ in water by the change of fluorescence color under UV light. Its detection limit for Hg2+ in aqueous solution is as low as 1 μM. In addition, CQDs@SiO2/CuNCs dual fluorescence emission composites successfully achieved the specific detection of Hg2+ in water samples from the South Lake of Changchun City. Compared with the traditional detection methods, this fluorescent composite has the advantages of convenience and long-term stability, and is more suitable for the rapid detection of mercury ions in the environment, which increases the practical application capability of fluorescent nanocomposites.