Method for preparing fluorine doped graphene quantum dot with excellent optical properties

Abstract

The invention discloses a method for preparing fluorine doped graphene quantum dot with excellent optical properties. The method comprises the steps of using low-cost and industrially produced pyrene as a precursor; performing nitration processing for the surface of pyrene at a low temperature; performing a hydrothermal reaction at a high temperature to remove the nitryl at the surface of the pyrene and then cutting the hexangular cyclic structure of the pyrene, so that graphene quantum dots excellent in water solubility, stable in structure, non-toxic, excellent in photoluminescent characteristics and small in size are prepared; performing a gas-phase reaction for the graphene quantum dots and xenon difluoride (XeF2) at 150 to 200 DEG C to synthesize the fluorine doped graphene quantum dots which are above 34 percent in fluorine content, 3 to 4 nm in crystal particle average particle size, and excellent in optical properties; the fluorine doped graphene quantum dot emits bright green fluorescence under the irradiating of 365 nm ultraviolet light. The method disclosed by the invention is simple, low in requirement on equipment and high in yield; other impurities are not generated.

Description

technical field [0001] The invention relates to a method for preparing graphene quantum dots with excellent water-soluble structure, stability, non-toxicity and small size. On the basis of such graphene quantum dots, a fluorine doped Graphene quantum dots. Background technique [0002] In recent years, nanomaterials with fluorescent properties have attracted the attention of many researchers at home and abroad. Among them, the zero-dimensional graphene quantum dots have a thickness of 0.5-1.5nm and a crystal diameter of less than 10nm. The surface contains hydroxyl and carboxyl groups. , carbonyl and other groups make it have good water solubility, and gradually enter the field of vision of scientists. According to authoritative predictions, functionalized graphene quantum dots will represent a new generation of quantum dots and play an increasingly important role in various application fields. Even a key role, because graphene quantum dots not only exhibit excellent proper...

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Problems solved by technology

[0002] In recent years, nanomaterials with fluorescent properties have attracted the attention of many researchers at home and abroad. Among them, the zero-dimensional graphene quantum dots have a thickness of 0.5-1.5nm and a crystal diameter of less than 10nm. The surface contains hydroxyl and carboxyl groups. , carbonyl and other groups make it have good water solubility, and gradually enter the field of vision of scientists. According to authoritative predictions, functionalized graphene quantum dots will represent a new generation of quantum dots and play an increasingly important role in various application fields. Even a key role, because graphene quantum dots not only exhibit excellent properties like graphene, but also have good biocompatibility, low toxicity, low annihilation, and stable chemical properties, showing unique characteristics in the field of bioimaging However, the fluorescent graphene quantum dots currently prepared cannot match the traditional quantum dots in terms of crystal quality and optical properties. The reasons: (1) Almost all of them are polycrystalline and highly defective in structure, so it is difficult to show Quantum effects unique to single crystal semiconductor quantum dots; (2) weak absorption in the visible light region, and low yield of fluorescent quantum dots; (3) difficult to grasp the size of quantum dots, so the fluorescence spectrum is very wide; (4) exhibits a high degree of PH dependence; (5) In order to fully demonstrate the unique advantages of graphene quantum dots and open up its applications in various aspects, one of the feasible methods is to do impurity atoms

[0003] Because nitrogen atoms have five valence electrons and have a comparable atomic size to carbon atoms, they have been widely used in the chemical doping of carbon materials, such as nitrogen-doped carbon nanotubes (N-CNT), etc., but fluorine-doped graphene Quantum dots are rarely studied. At present, the main methods for preparing fluorine-doped graphene quantum dots include high-temperature and high-pressure hydrothermal method, electrochemical and other methods, but many methods cannot avoid expensive equipment, troublesome and time-consuming operation, cumbersome process, and low yield Low, more impurities and other factors, which limit the wide application of fluorine-doped graphene quantum dots

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