Green and simple synthesis of NH2-functionalized CsPbBr3 perovskite nanocrystals for detection of iodide ion

The cesium lead halide perovskite nanocrystals (PNCs), an excellent fluorescent material, were limited in the field of analysis and detection applications as it is unstable in the polar solvent. Herein, a green and simple synthesis method of NH2-functionalized cesium lead halide perovskite nanocrystals (NH2-PNCs) were developed directly in ethanol using 3-aminopropyltriethoxysilane (APTES) as ligands. The characterization of the NH2-PNCs was measured by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier Transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The fluorescence property of the NH2-PNCs in ethanol/water mixed solvent was studied and it was found that the presence of the iodide ion in water would sensitively quench the fluorescence of the NH2-PNCs. This phenomenon is different from the anion exchange between traditional PNCs and halide ions in a non-polar solvent which induces the red-shift of the fluorescence peak of PNCs. The fluorescence quench of the NH2-PNCs is sensitive to iodide and iodide ion in the concentration range from 4.0 μM to 28.0 μM could be linearly detected with a limit of detection (LOD) of 1.0 μM (RSD = 1.66%, n = 11). The possible mechanism of the fluorescence quench of NH2-PNCs was also studied. The green and simple synthesis of functional perovskite nanocrystal for sensing analytes in an aqueous solution would lay the foundation for its applications in the field of analytical chemistry.