A lead-free Cs₂ZnCl₄ perovskite nanocrystals fluorescent probe for highly selective detection of norfloxacin

The abuse of antibiotics would seriously affect human health and has become of worldwide critical concern, thus it is urgent to develop an environmentally friendly and nontoxic fluorescent probe for antibiotics sensing. In this work, a lead-free Cs₂ZnCl₄ perovskite nanocrystals (PNCs) probe was fabricated for sensing norfloxacin (NOR) employing a modified ligand-assisted reprecipitation method. The prepared Cs₂ZnCl₄ PNCs probe had strong blue emission around 440 nm, and the characteristics of PNCs were systematically characterized by X-ray photoelectric spectroscopy (XPS), Fourier transforms infrared spectroscopy (FTIR), transmission electron microscope (TEM) and powder X-ray diffraction (XRD). The results revealed that the fluorescence intensity of the Cs₂ZnCl₄ PNCs was significantly enhanced after the introduction of norfloxacin. The Cs₂ZnCl₄ PNCs can be used as a fluorescent probe to selectively and sensitively detect norfloxacin in the concentration range from 0.2 to 50.0 μM, with a correlation coefficient (R²) of 0.9954 and the limit of detection (LOD, 3σ) of 0.1499 µM. The preparation and application of a lead-free perovskite fluorescent probe for norfloxacin would promote the application of perovskite fluorescent probes in biochemical assays.