Nitrogen and sulfur co-doped carbon quantum dots as fluorescence sensor for detection of lead ion

Abstract

• A fluorescent CQDs doped with nitrogen and sulfur were synthesized by one-step hydrothermal method. This method is facile, green and economical. • The addition of Pb 2+ quenched the fluorescence of carbon quantum dots. • The CQDs will be a good alternative for detection of Pb 2+ . A fluorescent carbon quantum dots (N-S CQDs) doped with nitrogen (N) and sulfur (S) with tunable wavelength was successfully prepared by one-step hydrothermal reaction for sensitive detection of Pb 2+ . The doping of N and S narrows the band gap of the CQDs and makes the wavelength red shift, so that the carbon quantum dots displayed maximum emission peak at 540 nm under 460 nm excitation. The addition of Pb 2+ quenched the fluorescence due to the specific combination of Pb 2+ with the carboxyl and sulfhydryl on the surface of the CQDs, forming a coordination structure. Under optimal conditions, the CQDs revealed outstanding anti-interference capability and a favorable linear relation was obtained in the scope of 0.2-12 μM and 40-200 μM with the limit of detection of 0.097 μM and 5.624 μM for Pb 2+ . Besides, the CQDs had been successfully used for monitoring Pb 2+ in river water with good accuracy and recovery. A fluorescent carbon quantum dots(N-S CQDs) doped with nitrogen, and sulfur with tunable wavelength was successfully prepared by one-step hydrothermal reaction for sensitive detection of Pb 2+ . The addition of Pb 2+ quenched the fluorescence due to the specific combination of Pb 2+ with the carboxyl and sulfhydryl on the surface of the CQDs.