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Method for preparing multicolor fluorescent graphene quantum dots by microwave process

A graphene quantum dot, microwave method technology, applied in chemical instruments and methods, luminescent materials, nanotechnology for materials and surface science, etc., can solve the problem of low yield of graphene quantum dots, short fluorescence emission wavelength, quantum Low yield and other problems, to achieve the effect of no obvious biological toxicity, high quantum yield and good dispersibility

Active Publication Date: 2015-04-01
WUHAN INST OF PHYSICS & MATHEMATICS CHINESE ACADEMY OF SCI
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  • Application Information

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Problems solved by technology

However, the graphene quantum dots prepared by these methods still have defects such as low yield, low quantum yield (3-11.5%) and short fluorescence emission wavelength (generally blue light and green light)

Method used

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  • Method for preparing multicolor fluorescent graphene quantum dots by microwave process
  • Method for preparing multicolor fluorescent graphene quantum dots by microwave process
  • Method for preparing multicolor fluorescent graphene quantum dots by microwave process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1: the preparation method of green fluorescent graphene quantum dot

[0028] Graphene oxide in this example was purchased from Nanjing Pioneer Nanomaterials Co., Ltd.

[0029] Add 20 mg graphene oxide to 10 mL concentrated HNO 3 (65%~68%) and 40mL concentrated H 2 SO 4 (98%) ultrasonic (300W, 42kHz) in the mixed liquid for 2 hours to make the graphene oxide disperse evenly. The resulting dispersion was heated to reflux at 95°C for 24 hours, carefully diluted with 200 mL of ultrapure water, and then added with K2 CO 3 or Na 2 CO 3 , to neutralize the excess acid in the diluent, and react until the pH of the solution is 8. After the reaction was complete, the obtained product was placed in a temperature environment of 4° C. for 3 hours. Remove the precipitated salt by suction filtration, transfer the obtained subnatant of suction filtration to a dialysis bag with a molecular weight of 3500 Da, and dialyze 5 times in ultrapure water (the volume of water u...

Embodiment 2

[0032] Embodiment 2: the preparation method of yellow fluorescent graphene quantum dot

[0033] The multi-walled carbon nanotubes in this example were purchased from Nanjing Pioneer Nanomaterials Co., Ltd.

[0034] Add 100mg multi-walled carbon nanotubes to 3.5mL ultrapure water, 10mL concentrated HNO 3 (65%~68%) and 35mL concentrated H 2 SO 4 (98%) ultrasonic (300W, 42kHz) in the mixed solution for 1 hour to disperse the multi-walled carbon nanotubes evenly. The resulting dispersion was heated to reflux at 105°C for 24 hours, carefully diluted with 200 mL of ultrapure water, and then added with K 2 CO 3 or Na 2 CO 3 , to neutralize the excess acid in the diluent, and react until the pH of the solution is 8. After the reaction is complete, place it in a temperature environment of 4°C for 3 hours. Remove the precipitated salt by suction filtration, transfer the obtained subnatant of suction filtration to a dialysis bag with a molecular weight of 3500 Da, and dialyze 5 t...

Embodiment 3

[0037] Embodiment 3: the preparation method of orange fluorescent graphene quantum dot

[0038] Multi-walled carbon nanotubes were purchased from Nanjing Pioneer Nanomaterials Co., Ltd.

[0039] Add 100mg multi-walled carbon nanotubes to 3.5mL ultrapure water, 10mL concentrated HNO 3 (65%~68%) and 35mL concentrated H 2 SO 4 (98%) ultrasonic (300W, 42kHz) in the mixed solution for 1 hour to disperse the multi-walled carbon nanotubes evenly. The resulting dispersion was heated to reflux at 105°C for 24 hours, carefully diluted with 200 mL of ultrapure water, and then added with K 2 CO 3 or Na 2 CO 3 , to neutralize the excess acid in the diluent, and react until the pH of the solution is 8. After the reaction is complete, place it in a temperature environment of 4°C for 3 hours. Remove the precipitated salt by suction filtration, transfer the obtained subnatant of suction filtration to a dialysis bag with a molecular weight of 3500 Da, and dialyze 5 times in ultrapure wa...

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Abstract

The invention discloses a method for preparing multicolor fluorescent graphene quantum dots by a microwave process. A carbon material is used as a reaction raw material to obtain the product by two reaction steps. The method comprises the following steps: 1. dispersing the carbon material in a mixed solution of water, concentrated nitric acid and concentrated sulfuric acid, carrying out thermal oxidation, dispersing the obtained mixed solution in water, neutralizing, desalting and drying to obtain an oxidized carbon material; and 2. dispersing the oxidized carbon material obtained in the step 1 in N,N-dimethylformamide under the ultrasonic action, reacting the dispersion solution in microwaves, filtering, desolventizing, redispersing and dialyzing to obtain the graphene quantum dots. The proportion of the water, concentrated nitric acid and concentrated sulfuric acid in the step 1 and the microwave reaction conditions in the step 2 can be controlled to obtain the graphene quantum dots with different fluorescent colors. The obtained graphene quantum dots have the advantages of high uniformity and stability, high fluorescence and high quantum yield, and have important application value in the fields of biological marker, fluorescent imaging and the like.

Description

technical field [0001] The invention relates to the field of preparation of nano-luminescent materials, in particular to a method for preparing multicolor fluorescent graphene quantum dots by a microwave method, which is applicable to the method for preparing multicolor fluorescent graphene quantum dots. Background technique [0002] Quantum dots are spherical or quasi-spherical semiconductor nanoparticles that are composed of a limited number of atoms and whose three dimensions are all below 100 nanometers (nm). The diameter of quantum dots is generally between 2 and 20 nm. Since electrons and holes are quantum-confined, the continuous energy band structure becomes a discrete energy level structure with molecular characteristics, which absorbs all photons with energy higher than its band gap. After that, fluorescence can be emitted. Based on quantum effects, quantum dots have broad application prospects in solar cells, light-emitting devices, optical biomarkers and other f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04B82Y30/00C09K11/65
Inventor 周欣杨玉琪陈世桢孙献平刘买利
Owner WUHAN INST OF PHYSICS & MATHEMATICS CHINESE ACADEMY OF SCI
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