Characterization of the Uptake of Quantum Dots by Algae
0
Citation
0
Reference
20
Related Paper
Keywords:
Characterization
Cite
Carbon Quantum Dots
Carbon fibers
Cite
Citations (0)
As a new type of fluorescent carbon nanomaterials, carbon quantum dots have been widely concerned in recent years because of their good biocompatibility, low cytotoxicity and easy surface functionalization. In this paper, nitrogen-doped carbon quantum dots (N-CQDs) were prepared by one-step hydrothermal method with citric acid as the carbon source and urea as a nitrogen source. The fluorescence spectrophotometer, Fourier infrared spectrometer, X-ray diffractometer, and transmission electron microscope were utilized to discover the luminescence properties, structural characteristics, morphology and size of the synthesized N-CQDs. The results showed that the best reaction conditions for preparing N-CQDs were as follows: the hydrothermal process parameters were 240 °C for 10 h, and the concentration of nitrogen doping was 0.6 wt%. Under these conditions, the prepared N-CQDs with bright blue fluorescence solution was uniform and stable. And the results showed the structural characteristics were weak crystalline graphite carbon, and the shape characteristics were nearly spherical quantum dot with about 5–10 nm diameters.
Diffractometer
Carbon fibers
Nanomaterials
Quantum yield
Hydrothermal Synthesis
Surface Modification
Biocompatibility
Cite
Citations (19)
Lead sulfide
Lead (geology)
Cite
Citations (0)
Cite
Citations (0)
Cite
Citations (5)
Despite a growing interest in carbon dots (CDs), notably for their potential as a more sustainable, less toxic alternative to inorganic quantum dots, the critical factors affecting their physical, chemical, and optical properties are relatively unknown, limiting their widespread use. Herein, a one-pot hydrothermal method was used to synthesize CDs from citric acid and phenylalanine. CDs were synthesized over a range of reactant ratios, from pure citric acid to pure phenylalanine and seven mixed ratios in between, achieving a quantum yield (QY) as high as 65% with a peak excitation/emission of 350/413 nm. The goal was to determine the role of stoichiometry on the chemical and structural composition of CDs, particularly its impact on nitrogen doping, and in turn its effect on QY. We showed that a wide range of reactant ratios tend toward reacting in a stoichiometric 2:1 molar ratio of phenylalanine to citric acid whereby the resulting CDs have similar chemical composition and QY. Using this ratio may lead to a more efficient and sustainable mass production process by reducing and reusing reactant waste. The QY of the CDs was found to be more dependent on the oxygen-to-carbon ratio and the relative amount of carboxyl oxygen in the CD than it was on the nitrogen-to-carbon ratio. The resulting CDs also showed Fe3+ sensing capabilities through static fluorescence quenching with a limit of detection of 3.5 μM. This study provides new insights which may be useful for the optimization of the green synthesis of CDs for more widespread applications.
Quantum yield
Stoichiometry
Carbon fibers
Hydrothermal Synthesis
Cite
Citations (108)
Carbon Quantum Dots
Polyethylenimine
Carbon fibers
Quantum yield
Polyamine
Chemical modification
Cite
Citations (576)
A green method is used to synthesize nitrogen‐doped carbon quantum dots (N‐CQDs) using dried scindapsus leaves as the carbon source. The average diameter of the N‐CQDs varies from 2 to 6 nm. The N‐CQDs emit blue light, and the emission wavelength exhibits excitation wavelength dependence. The characteristic peak is found to originate from a N‐related state. The surface defects and quantum effects of the CQDs play a strong role in the luminescence process and resulted in the excitation wavelength dependence of the photoluminescence, which is confirmed by changing the solvent to ethanol. This work can encourage the exploration of new carbon sources to synthesize doped CQDs and stimulate investigation of the photoluminescence mechanism of CQDs.
Carbon fibers
Carbon Quantum Dots
Excitation wavelength
Carbon source
Cite
Citations (14)
Cite
Citations (28)
Abstract Nitrogen‐rich quantum dots (N‐dots) were serendipitously synthesized in methanol or aqueous solution at a reaction temperature as low as 50 °C. These N‐dots have a small size (less than 10 nm) and contain a high percentage of the element nitrogen, and are thus a new member of quantum‐dot family. These N‐dots show unique and distinct photoluminescence properties with an increasing percentage of nitrogen compared to the neighboring carbon dots. The photoluminescence behavior was adjusted from blue to green simply through variation of the reaction temperature. Furthermore, the detailed mechanism of N‐dot formation was also proposed with the trapped intermediate. These N‐dots have also shown promising applications as fluorescent ink and biocompatible staining in C. elegans.
Liquid nitrogen
Carbon fibers
Carbon Quantum Dots
Cite
Citations (261)