Facile synthesis of nitrogen and sulfur co-doped carbon dots and application for Fe(III) ions detection and cell imaging

Novel fluorescent nitrogen and sulfur co-doped carbon dots (N,S,C-dots) were synthesized by hydrothermal treatment of garlic. It was confirmed that the prepared fluorescent nanodots were doped with nitrogen and sulfur in the format of pyridinic-N, pyrrolic-N and thiophene-S. The N,S,C-dots displayed strong fluorescence with quantum yield of 13%, and the fluorescence can be efficiently quenched by Fe3+. Based on the results, Fe3+ sensor was successfully developed and utilized to detect Fe3+ in environmental waters with excellent sensitivity and repeatability. Eventually, the carbon dots were applied for cell imaging, demonstrating their potential toward diverse applications.