Rapid synthesis of nitrogen-doped carbon dots by microwave method for sensitive detection of co(II) in water environment

Novel nitrogen-doped carbon dots (N-CDs) were prepared by microwave method using o -phenylenediamine and formamide as raw materials, and the N-CDs were used successfully for sensing Co(II) on the basis of photoluminescence quenching. The structural characterization of the obtained N-CDs was thoroughly performed by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) spectroscopy. The optical properties were also determined by absorption and fluorescence spectra. N-CDs have bright yellow fluorescence emission and high quantum yield (29 %), with a detection limit as low as 0.38 μM. In order to detect Co(II) more conveniently and quickly, N-CDs/PVA fluorescence composite film was prepared by compounding N-CDs with polyvinyl alcohol. The fluorescence composite film combines the fluorescence characteristics of N-CDs and the stability of polyvinyl alcohol. The application range of Co(II) visual detector in the water environment is expanded.