Solvothermal synthesis of phosphorus and nitrogen doped carbon quantum dots as a fluorescent probe for iron(III)
- 554 Downloads
Carbon quantum dots (CQDs) doped with phosphorus and nitrogen were prepared via a hydrothermal method starting from citric acid, urea and phosphoric acid in dimethylformamide solution. The size, morphology, surface composition, energy levels, and optical properties of the CQDs were characterized. They show both green down-conversion and up-conversion fluorescence. Ferric ions (Fe3+) are found to quench the fluorescence. Cyclic voltammetry was used to identify the HOMO and LUMO levels of the doped CQDs. The quenching mechanism, as confirmed by energy level calculations and absorption spectra, can be attributed to the selective coordination of Fe3+ by the surface functional groups on the CQDs. This facilitates the photo-induced electron transfer from the CQDs to the d orbitals of Fe3+. The CQDs are shown to be viable fluorescent probes for determination of Fe3+ with high selectivity and sensitivity. The assay has a linear response in the 0.1 μM to 0.9 μM Fe3+ concentration range and a 50 nM as limit of detection (at a S/N ratio of 3).
KeywordsCarbon quantum dots (CQDs) Ferric ions Phosphorus doping Nitrogen doping Fluorescent probe Photo-electron transfer Cyclic voltammetry
The authors would like to thank the ministry of higher education and scientific research in Kurdistan for supporting this work.
Compliance with ethical standards
The author(s) declare that they have no competing interests.
- 4.Omer KM, Ku S-Y, Cheng J-Z, Chou S-H, Wong K-T, Bard AJ (2011) Electrochemistry and electrogenerated chemiluminescence of a spirobifluorene-based donor (triphenylamine)−acceptor (2,1,3-Benzothiadiazole) molecule and its organic nanoparticles. J Am Chem Soc 133(14):5492–5499. https://doi.org/10.1021/ja2000825 CrossRefPubMedGoogle Scholar
- 5.Omer KM, Ku S-Y, Chen Y-C, Wong K-T, Bard AJ (2010) Electrochemical behavior and electrogenerated chemiluminescence of star-shaped D−A compounds with a 1,3,5-triazine core and substituted Fluorene arms. J Am Chem Soc 132(31):10944–10952. https://doi.org/10.1021/ja104160f CrossRefPubMedGoogle Scholar
- 22.Omer KM, Mohammad NN, Baban SO (2018) Up-conversion fluorescence of phosphorous and nitrogen co-doped carbon quantum dots (CDs) coupled with weak LED light source for full-spectrum driven photocatalytic degradation via ZnO-CDs nanocomposites. Catal Lett 148:2746–2755. https://doi.org/10.1007/s10562-018-2459-4 CrossRefGoogle Scholar
- 27.Liu S, Tian J, Wang L, Zhang Y, Qin X, Luo Y, Asiri AM, Al-Youbi AO, Sun X (2012) Hydrothermal treatment of grass: a low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu (II) ions. Adv Mater 24(15):2037–2041CrossRefGoogle Scholar