Synthesis of a water‐stable CsPbBr3 perovskite for selective detection of mercury ion in water.

By using the method of low‐temperature crystallization, CsPbBr3 perovskite nanocrystals (PNCs) coated with trifluoroacetyl lysine (Tfa‐Lys) and oleamine (Olam) were synthesized in aqueous solution. The structure of the CsPbBr3 PNCs was characterized by many methods, such as ultraviolet (UV)‐visible absorption spectrophotometer, fluorescence spectrophotometer, transmission electron microscopy (TEM), and X‐ray diffraction (XRD) pattern. The fluorescence emission of the CsPbBr3 PNCs is stable in water for about 1 day at room temperature. It was also found that the fluorescence of the PNCs could be obviously and selectively quenched after the addition of mercury ion (Hg2+), allowing a visual detection of Hg2+ by the naked eye under UV light illumination. The fluorescence quenching rate (I0/I) has a good linear relationship with the addition of Hg2+ in the concentration range 0.075 to 1.5 mg/L, with a correlation coefficient (R2) of 0.997, and limit of detection of 0.046 mg/L. The fluorescence quenching mechanism of the PNCs was determined by the fluorescence lifetime and X‐ray photoelectron spectroscopy (XPS) of the PNCs. Overall, the synthesis method for CsPbBr3 PNCs is simple and rapid, and the as‐prepared PNCs are stable in water that could be conveniently used for selective detection of Hg2+ in the water environment. [ABSTRACT FROM AUTHOR]