Method for preparing yellow or green carbon dots

Abstract

The invention discloses a method for preparing yellow or green carbon dots. The method comprises the following steps: (1) dispersing a carbon source, a passivator and a reducer into ultrapure water, and stirring under the protection of protective gas to obtain a mixed solution; (2) performing heating reaction on the mixed solution obtained in the step (1) in a reaction container to obtain a carbondot solution; and (3) directly placing the carbon dot solution obtained in the step (2) into an ultrafiltration pipe or mixing the carbon dot solution and an organic reagent, and then centrifuging and drying to obtain the solid carbon dots. Based on the synergistic effect of the passivator and the reducer, the green or yellow carbon dots with high quantum yield are further synthesized by a simpleaqueous phase method, the carbon dots with different emitting wavelength can be synthesized by adjusting the mass ratio of the carbon source to the passivator to the reducer, the quantum yield of thegreen carbon dots is 22.5 percent and the quantum yield of the yellow carbon dots is 18.4 percent.

Description

technical field [0001] The invention belongs to the technical field of nanometer materials, and more specifically relates to a method for preparing yellow or green carbon dots. Background technique [0002] Carbon quantum dots (i.e., carbon dots) are a new type of carbon nanomaterials. Compared with traditional semiconductor quantum dots and organic dyes, they have the advantages of low toxicity, good biocompatibility, adjustable luminous range, and easy functionalization. It has broad application prospects in the fields of biomedicine, optoelectronics, catalysis and sensing. There are various methods for preparing carbon dots, but most of the methods synthesized are carbon dots with blue fluorescence. Due to the poor penetration of short-wavelength (blue) carbon dots to tissues, the optical imaging of deep tissues in the body is limited. In addition, almost all biological tissues produce autofluorescence for short-wavelength visible light, which interferes with the imaging...

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Problems solved by technology

[0004] For the above defects or improvement needs of the prior art, the object of the present invention is to provide a method for preparing yellow or green carbon dots, wherein through the overall flow process of the preparation method, and the conditions and parameters used in key synthetic reactions (including The types and proportions of reaction raw materials, etc.) are improved, which can effectively solve the problem of difficult preparation of yellow or green carbon dots compared with the prior art. Most of the methods in the prior art prepare blue carbon dots, and only a small part of them prepares The method of yellow or green carbon dots, but these methods have the problems of low quantum yield, complicated operation, and high requirements for equipment. The present invention is based on the synergistic effect of passivating agent and reducing agent, and synthesizes high Green or yellow carbon dots with quantum yield, and preferably through the overall coordination of the various parameters of the preparation method, especially by changing the ratio of reactants to synthesize fluorescent carbon dots of different colors, yellow carbon dots or green carbon dots can be prepared separately , the quantum yield of the green carbon dots in the present invention is 22.5%, and the quantum yield of the yellow carbon dots is 18.4%; the raw materials of the present invention are cheap and easy to obtain, the operation is green and environmentally friendly, and the synthesized carbon dots have good water solubility, stable photochemical performance, and quantum yield. The yield is high, and it has broad application prospects in the fields of fluorescent labeling, imaging, analysis and detection.

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