High quantum yield nitrogen doped carbon dots for Ag+ sensing and bioimaging

N-doped carbon dots (NCDs) with green fluorescence is developed by the hydrothermal reaction with o-aminophenol and ethylenediamine as carbon and nitrogen sources, and the quantum yield (QY) is 38.4%. The NCDs are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible absorption spectroscopy (UV–vis) and fluorescence spectroscopy. The results show that NCDs have good fluorescence properties and stability, and the NCDs are further utilized as a sensor for Ag+ via the static quenching effect (SQE) (λex=430 nm, λem=510 nm). The linear range of Ag+ is 30–210 µmol/L with a limit of detection (LOD) of 4.7 µmol/L (S/N = 3). On this basis, we quantitatively detect Ag+ in real samples. Furthermore, due to the excellent fluorescence performance, the NCDs are found to be an effective tool for Ag+ sensing in bioimaging.