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Preparation method of super-high-quantum-yield carbon quantum dots with citric acid-urea as raw materials

A quantum yield, carbon quantum dot technology, applied in chemical instruments and methods, luminescent materials, etc., can solve the problems of uncontrollable microwave temperature, low fluorescence efficiency, low fluorescence yield, etc. Inexpensive and readily available materials, and the effect of high fluorescence stability

Inactive Publication Date: 2016-01-27
DONGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It has been reported that fluorescent carbon dots are prepared by microwave pyrolysis of various amino acids, but there are disadvantages such as uncontrollable microwave temperature (local hot spots) and low fluorescence efficiency.
The preparation of fluorescent carbon dots by hydrothermal method not only has the advantages of uniform nucleation and controllable particle size, but in the current reports, most of the fluorescence yields of carbon particle quantum dots are not high.

Method used

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  • Preparation method of super-high-quantum-yield carbon quantum dots with citric acid-urea as raw materials
  • Preparation method of super-high-quantum-yield carbon quantum dots with citric acid-urea as raw materials
  • Preparation method of super-high-quantum-yield carbon quantum dots with citric acid-urea as raw materials

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Mix citric acid, urea and distilled water (the mass ratio is 1.2g:0.8g:20g), stir and dissolve to obtain a mixed solution;

[0030] (2) Place the mixture in (1) in a 100mL autoclave at 170°C for a hydrothermal reaction for 1.5 hours to obtain a hydrothermal product;

[0031] (3) Dry the hydrothermal product obtained in (2) overnight at 60°C;

[0032] (4) Place the oven-dried product obtained in (3) in an environment of 250°C and calcinate for 0.5h at a heating rate of 10°C / min to obtain the calcined product;

[0033] (5) Grind the calcined product obtained in (4) to fully dissolve in distilled water, and filter with a 0.22 μm water-based filter membrane to obtain a carbon dot solution with uniform particle size.

[0034] The preparation method flow chart is as figure 1 Shown. figure 2 It is a transmission electron microscope image of the fluorescent quantum dots of carbon particles in Example 1, and the average particle size of the particles is about 6.64 nm. image 3 It is...

Embodiment 2

[0036] (1) Mix citric acid, urea and distilled water (the mass ratio is 1.2g:0.8g:25g), stir and dissolve to obtain a mixed solution;

[0037] (2) Place the mixture in (1) in a 100mL autoclave at 170°C for a hydrothermal reaction for 1.5 hours to obtain a hydrothermal product;

[0038] (3) Dry the hydrothermal product obtained in (2) overnight at 60°C;

[0039] (4) Place the oven-dried product obtained in (3) in an environment of 250°C and calcinate for 0.5h at a heating rate of 10°C / min to obtain the calcined product;

[0040] (5) Grind the calcined product obtained in (4) to fully dissolve in distilled water, and filter with a 0.22 μm water-based filter membrane to obtain a carbon dot solution with uniform particle size.

[0041] Image 6 It is a comparison diagram of the fluorescence intensity of carbon particle fluorescent quantum dots under different environmental pH. It can be seen from the figure that the fluorescence intensity of the carbon dot solution is the strongest when th...

Embodiment 3

[0043] (1) Mix citric acid, urea and distilled water (the mass ratio is 1.2g:0.8g:20g), stir and dissolve to obtain a mixed solution;

[0044] (2) Place the mixture in (1) in a 100mL autoclave at 170°C for a hydrothermal reaction for 0.5 to 3 hours to obtain a hydrothermal product;

[0045] (3) Dry the hydrothermal product obtained in (2) overnight at 60°C;

[0046] (4) Place the oven-dried product obtained in (3) to calcinate for 1 hour at a temperature of 300°C with a heating rate of 10°C / min to obtain the calcined product;

[0047] (5) Grind the calcined product obtained in (4) to fully dissolve in distilled water, and filter with a 0.22 μm water-based filter membrane to obtain a carbon dot solution with uniform particle size.

[0048] Figure 5 Fluorescence intensity of citric acid-urea (urea) carbon particles fluorescent quantum dots prepared by a two-step hydrothermal-pyrolysis method under different hydrothermal time (0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h) Comparing the graph, it c...

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Abstract

The invention relates to a preparation method of super-high-quantum-yield carbon quantum dots with citric acid-urea as raw materials. The preparation method includes the steps that citric acid and urea serve as the raw materials for a hydrothermal reaction, a hydrothermal product is obtained and dried, pyrolysis calcination is conducted, and a calcined product is obtained; the calcined product is ground and filtered, and then the super-high-quantum-yield carbon quantum dots are obtained. The preparation method is mild in reaction condition and easy and convenient to operate, and the raw materials are easy to obtain, cheap and environmentally friendly. The prepared carbon quantum dots are high in quantum efficiency, good in monodispersity, stable in luminescent performance, free of twinkling phenomena, good in biocompatibility and the like.

Description

Technical field [0001] The invention belongs to the field of preparation of carbon quantum dots, and particularly relates to a preparation method of ultra-high quantum yield carbon quantum dots using citric acid-urea as raw materials. Background technique [0002] In recent years, since traditionally provided fluorescent dyes are easily photobleached after repeated excitations, and their fluorescence performance is weakened, semiconductor quantum dots with similar light conversion performance are increasingly used in biomarkers and scientific research materials. However, traditional semiconductor quantum dots are often heavy metal quantum dots, and their inherent shortcomings such as poor biocompatibility and easy "light blinking" phenomenon have seriously affected the expansion of their application range. In addition to these shortcomings, the inherent biological toxicity of traditional labeling substances limits the amount of addition and the quantum yield of some labeling subs...

Claims

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Application Information

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IPC IPC(8): C01B31/02C09K11/65
Inventor 周兴平郑楠楠毕森林
Owner DONGHUA UNIV
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