One-step microwave synthesis of N,S co-doped carbon dots from 1,6-hexanediamine dihydrochloride for cell imaging and ion detection.

As a new member of the fluorescent carbon nanomaterial family, carbon dots (CDs) not only have outstanding photoluminescence properties and small size characteristics, but also contain favourable low cytotoxicity and biocompatibility, which could be the best choice to detect of ions to replace quantum dots for ions detection. Here, the N,S co-doped carbon dots (N/S-CDs) was synthesized by one-step microwave using 1,6-hexanediamine dihydrochloride and dimethyl sulfoxide as precursors, and their morphology and structure were characterized by TEM, XRD, XPS and FTIR. The optimal emission wavelength of the CDs was 512 nm with green fluorescence, and was red-shifted gradually as the excitation wavelength aggrandized. The synthesized CDs owned a well quantum yield of 24 %. It was further applied for the detection of MnO4- and Cr2O72- with an excellent detection limit of 0.34 µM and 0.23µM, respectively. Cr2O72- did not influence the N/S-CDs PL response of MnO4- in the presence of excessive Pb2+. Moreover, the obtained N/S-CDs demonstrated preeminent biocompatibility and could be resoundingly applied for cellular imaging.