Sensitive "On-Off" Fluorescent Sensor From N-Doped Carbon Dots for Fe³⁺ Detection and Anticounterfeiting Applications

Herein, a kind of N-doped fluorescent carbon dots (N-CDs) were prepared by using melamine and carboxymethyl cellulose (CMC) as precursors through a straightforward hydrothermal method. The designed sensor displayed a uniform nanoscale distribution, excellent hydrophilicity, and strong fluorescence emission with a fluorescence quantum yield of 37.98%. Moreover, the N-CDs could be utilized for Fe³⁺ detection by the fluorescence "On-Off" transition via the mechanism of internal filtration effect (IFE) and static quenching process. Two good linear relationships within the concentrations of Fe³⁺ from 10 to 100μM and 100 to 500 μM could be obtained, which indicated that the "On-Off" fluorescent sensor could quantitative analysis of Fe³⁺ and the calculated detection limit (LOD) was 0.510 μM (3σ/slope). Additionally, the N-CDs could be used for the detection of Fe³⁺ in the solid phase based on the fluorescence "On-Off" strategy, which is promising for anticounterfeiting application.