Hydrothermal synthesis of nitrogen and boron doped carbon quantum dots with yellow-green emission for sensing Cr(vi), anti-counterfeiting and cell imaging

Abstract

Nitrogen and boron doped carbon quantum dots (NB-CQDs) with yellow-green emission were prepared via hydrothermal method using 2-hydroxyphenylboronic acid and ethylenediamine in aqueous solution.The as-prepared NB-CQDs exhibited bright yellow-green emission, excellent stability in aqueous solution with high ionic strength and good biocompatibility. We further explored the applications of NBCQDs for sensing metal ions in aqueous solution. We found that the NB-CQDs could be utilized to sense Cr 2 O 7 2À in aqueous solution due to the Cr 2 O 7 2À-induced fluorescence quenching. In the sensing system, as low as 0.5 mM Cr 2 O 7 2À can be successfully detected and a good linear relationship in the range of 0-250 mM has been obtained. And the NB-CQDs can be also used as ink for writing on paper, revealing the NB-CQDs can be applied for anti-counterfeiting. Moreover, the NB-CQDs exhibit negligible cytotoxicity and good biocompatibility, which is favorable for bioimaging applications. And the NB-CQDs were successfully applied for fluorescence imaging in HeLa cells.

Studies of the effect of halide ions on the fluorescence of quinine sulfate

“…Furthermore, the fluorescence of quinine sulfate was greatly quenched (Figure ) . The changed UV‐visible absorption spectra revealed that the fluorescence quenching mechanism of quinine sulfate caused by halide ions is a static quenching process . Therefore, the halide ions‐caused fluorescence quenching mechanism of quinine sulfate varied with halide ions.…”

“…Quinine is a type of medicine, which has been used for malaria therapy . To date, quinine sulfate is widely used as a reference to calculate the quantum yield of various fluorescent materials . In analytical chemistry experiments, quinine sulfate is also applied to model fluorescent molecules to study the molecular fluorescence owing to the high quantum yield and good solubility in water .…”

Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

“…In an investigation, Guo et al synthesized B and N co-doped CQDs with yellow-green emission and QY of 6.59% via hydrothermal method (12 h at 180 • C) using 2-hydroxyphenylboronic acid and ethylenediamine as the starting materials-(as shown in Figure 6), where these CQDs have displayed better stability in aqueous solution with high ionic strength (0.25-1.2 M of NaCl) and different pH of 3-13 [110]. However, Huang et al synthesized B and N co-doped CQDs with green emission and improved QY of 47% via hydrothermal method (7 h at 160 • C) by using 3-aminobenzeneboronic acid and 1,2-ethylenediamine as precursors [111].…”

“…Guo et al found that B and N co-doped CQDs could be used as fluorescent ink for writing letters/numbers/Chinese characters on Xuan Paper and weighing paper for anti-counterfeiting-as shown in Figure 13 [110]. These letters/number/characters have gradually changed from light yellow to colorless (under visible light) with the decrease in the concentration of the CQDs.…”

One‐Pot Hydrothermal Synthesis of Elements (B, N, P)‐Doped Fluorescent Carbon Dots for Cell Labelling, Differentiation and Outgrowth of Neuronal Cells

“…Doping of nitrogen into carbon dots (N@CDs) have been reported widely . Recently, the advantages of boron (B), sulfur (S), phosphorous (P), and other metal ion doping have been demonstrated by several researcher . However, doping with different materials rarely touched and need to be explore.…”