Preparation method of graphene quantum dots

A graphene quantum dot and graphene technology, applied in the direction of zinc oxide/zinc hydroxide, etc., can solve the problems of cumbersome, widened fluorescence wavelength, low quantum yield, etc., and achieve the effect of simple process

Active Publication Date: 2014-12-24
湖北高地石墨烯科技有限公司
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Problems solved by technology

Among them, there is always a problem in the top-down method, that is, there is no way to control the size distribution of graphene quantum dots, and the bottom-up method is too cumbersome, which is not conducive to industrial production and expanded application.
The size distribution of graphene quantum dots is too wide, which will lead to various non-radiative transitions between graphene quantum dots, thereby reducing energy, making the obtained graphene quantum dots have a low quantum yield, and the fluorescence wavelength becomes wider, losing its application significance

Method used

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preparation example Construction

[0028] see figure 1 , a method for preparing graphene quantum dots in one embodiment, including the following steps 110 to 150.

[0029] Step 110: providing zinc oxide with a hexagonal crystal structure as a seed crystal nucleus, and the particle size of the zinc oxide with a hexagonal crystal structure is 5nm-30nm.

[0030] The [1000] and [1111] crystal planes of zinc oxide having a hexagonal crystal structure are the exposed crystal planes. Graphene and graphene oxide are easier to grow on the [1000] and [1111] crystal planes of zinc oxide with a hexagonal crystal structure. Zinc oxide with a hexagonal crystal structure is used as a seed nucleus to induce the growth of graphene quantum dots, and the size of graphene quantum dots can be indirectly controlled by controlling the particle size of zinc oxide with a hexagonal crystal phase structure.

[0031] The particle size of zinc oxide having a hexagonal crystal structure is 5 nm to 30 nm. Zinc oxide with a hexagonal cryst...

Embodiment 1

[0070] 1. Dissolve zinc acetate in ethanol, heat in a water bath at 50°C for 1 hour, then add polymethylpyrrolidone to obtain the first solution. Wherein, the mass percent concentration of zinc acetate is 5%, and the mass percent concentration of polymethylpyrrolidone is 0.2%. Mix ammonia water with a mass percent concentration of 25% and absolute ethanol at a volume ratio of 1:5 to prepare a mixed solution of ammonia water and ethanol, and add sodium hydroxide to obtain a second solution. Wherein, the concentration of sodium hydroxide in the second solution is 0.1mg / L. Mix the first solution and the second solution at a volume ratio of 1:1, stir at a rate of 60rpm for 2h, then centrifuge at a rate of 3000rpm for 5min, take the precipitate, wash the precipitate to obtain zinc oxide with a hexagonal crystal structure, which has a hexagonal crystal structure The zinc oxide is spherical and the particle size is 7.5nm.

[0071] 2. Add single-layer graphene oxide to deionized wat...

Embodiment 2

[0077] 1. Dissolve zinc chloride in isopropanol, heat in a water bath at 60°C for 2 hours, then add hydroxypropyl cellulose to obtain the first solution. Wherein, the mass percentage concentration of zinc chloride is 25%, and the mass percentage concentration of hydroxypropyl cellulose is 1%. Mix ammonia water with a mass percent concentration of 25% and absolute ethanol at a volume ratio of 1:8 to prepare a mixed solution of ammonia water and ethanol, and add potassium hydroxide to obtain a second solution. Wherein, the concentration of potassium hydroxide in the second solution is 0.5mg / L. The first solution and the second solution were mixed at a volume ratio of 2:1, stirred at a rate of 30rpm for 3h, then centrifuged at a rate of 4000rpm for 15min, the precipitate was taken, and the precipitate was washed to obtain zinc oxide with a hexagonal crystal structure, which had a hexagonal crystal structure The zinc oxide is hexagonal and the particle size is 15nm.

[0078] 2. ...

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Abstract

The invention relates to a preparation method of graphene quantum dots. The preparation method comprises the following steps: taking zinc oxide adopting a hexagonal crystal structure and having the grain diameter of 5 nm to 30 nm as a seed crystal nucleus; adding single-layer graphene oxide into solvent to prepare graphene oxide dispersion liquid, adding zinc oxide adopting a hexagonal crystal structure, then adding a stabilizer, and uniformly dispersing to obtain a colloidal solution; performing hydrothermal reaction on the colloidal solution for 0.5 h to 2 h at 160 DEG C to 300 DEG C to obtain turbid liquid containing graphene quantum dots; adding acid to the turbid liquid containing graphene quantum dots to clarify the turbid liquid containing graphene quantum dots, filtering, regulating the pH value of the filter liquor to be 7 to 8, stirring and filtering to obtain a solution containing graphene quantum dots; extracting the solution containing graphene quantum dots, and evaporating to remove an extractant so as to obtain graphene quantum dots. The method is relatively simple in technology and can be used for preparing graphene quantum dots which are narrower in size distribution.

Description

technical field [0001] The invention relates to the technical field of graphene quantum dots, in particular to a preparation method of graphene quantum dots. Background technique [0002] At present, in the research of graphene quantum dots, the main preparation methods can be divided into top-down and bottom-up methods. The top-down method, that is, cracking graphene to obtain graphene quantum dots, includes secondary oxidation, electron beam or ion beam etching, hydrothermal cracking or solvothermal cracking, and microscopic cutting of carbon materials. method; while the bottom-up method is mainly an organic synthesis method starting from small organic molecules. Among them, there is always a problem in the top-down method, that is, there is no way to control the size distribution of graphene quantum dots, and the bottom-up method is too cumbersome, which is not conducive to industrial production and expanded application. The size distribution of graphene quantum dots is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04C01G9/02
Inventor 张麟德张明东
Owner 湖北高地石墨烯科技有限公司
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