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

N-doped carbon dots (N CDs) 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 N CDs 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 N CDs have good fluorescence properties and stability, and the N CDs are further utilized as a sensor for Ag + via the static quenching effect (SQE) (λ ex =430 nm, λ em =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 N CDs are found to be an effective tool for Ag + sensing in bioimaging.