Facile one-pot synthesis of highly fluorescent nitrogen-doped carbon dots by mild hydrothermal method and their applications in detection of Cr(VI) ions

Nitrogen-doped carbon dots (N-CDs) with well-distribution size and strong blue emission were successfully synthesized via a simple mild hydrothermal strategy using citric acid and ethylenediamine as co-precursors. The highly fluorescent N-CDs exhibit high fluorescence quantum yield (QY, 58.6%), excitation-independent emission behavior, and good photostability. The experimental results showed that the N-CDs can be served as a fluorescent sensing platform for detection of Cr(VI) ions due to the effective fluorescence quenching effect of Cr(VI) ions. The quenching mechanism probably arises from the inner filter effect (IFE) and the electron transfer due to the strong interactions between functional groups ( COOH, OH and NH 2 groups) of the N-CDs and Cr(VI) ions. It is also found that the N-CDs showed high sensitivity toward Cr(VI) ions with a detection limit of 0.26 μM. Moreover, the obtained N-CD can be employed as chemsensor to detect Cr (VI) in real river water samples, which have potential applications in the environmental water.