A novel fluorescent Si/CDs for highly sensitive Hg2+ sensing in water environment

A blue fluorescent Si/CDs is successfully synthesized via a conventional solvothermal method, which can serve as a sensitive fluorescent sensor to detect Hg2+ ions in water. The synthesized Si/CDs material exhibits excellent optical properties, high chemical and structural stability in an aqueous solution. Under natural light, the mixture is a colorless suspension while under ultraviolet light, it can emit bright blue fluorescence and the maximum excitation and emission wavelengths are 377 and 464 nm, respectively. Particularly, Hg2+ can lead to nearly complete fluorescence quenching of the material suspension and the emission intensity of the constructed fluorescent sensing system linearly decreases with increasing Hg2+ concentration in the range of 0–200 μM with a detection limit of 26.7 nM (S/N = 3). The proposed method has been successfully applied in detection of Hg2+ content in environmental and drinking water samples. In addition, the test paper strips based on fluorescent Si/CDs are also prepared by an immersion method for rapid and quantitative detection of Hg2+ in water environment through a visual mode.