A design strategy of ratiometric optical probe for Fe3+ ions and ascorbic acid detection based on europium-doped carbon dots

Rare-earth doped carbon dots represent a new generation of nanomaterials, which achieve the functional modulation and property optimization of carbon dots materials. In this paper, Eu 3+ -doped carbon dots (Eu-CDs) were prepared employing a one-step hydrothermal approach. The structure and properties of Eu-CDs were characterize using a transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, etc. Eu-CDs exhibit a series of distinct emission peaks at 467, 595, 620 and 702 nm when excited at 395 nm, respectively. An “off-on” strategy for detecting of Fe 3+ and ascorbic acid was established on the basis of changes in luminescence peak intensity ratios of the CDs and Eu 3+ , which effectively reduces the detection limit compared with single-peak detection. The I 467 / I 595 of Eu-CDs exhibits an excellent linear association with the concentrations of Fe 3+ or ascorbic acid, and the limit of detections are 0.15 and 0.13 μmol/L, respectively, indicating that Eu-CDs can be applied for the quantitative measurement of Fe 3+ and ascorbic acid, and are successfully applied in real samples.