Fluorescence carbon quantum dots, and preparation method and application thereof

Abstract

The invention discloses high-quantum-yield fluorescence carbon quantum dots and a preparation method thereof. The method comprises the following steps: by using chitosan as a carbon source, adding glacial acetic acid and ethylenediamine, and sufficiently stirring to obtain a paste; reacting in a microwave oven to finally obtain a black solid; taking out, naturally cooling, adding a certain amount of secondary water, dissolving by stirring to obtain a brown solution, removing the insoluble substance to obtain a brown solution, dialyzing to remove impurities to obtain a fluorescence carbon quantum dot water solution, and carrying out freeze-drying to obtain the fluorescence carbon quantum dots. The method has the advantages of simple technique, wide raw material sources, low price, low requirements for preparation conditions and higher quantum yield of the obtained carbon quantum dots. The obtained fluorescence carbon quantum dots can be used for detecting Fe<3+> in a water body, and can also be used in living cell fluorescence imaging.

Description

technical field [0001] The invention relates to a luminescent nanometer material, in particular to a carbon quantum dot, in particular to a fluorescent carbon quantum dot with high quantum yield and its preparation method and application. Background technique [0002] Carbon quantum dots (carbon dots, C-Dots) are a carbon-based quantum dot discovered for the first time by Scrivens et al. A new type of nanomaterial with a skeleton structure. Compared with traditional semiconductor quantum dots and organic dyes, carbon quantum dots, as a new type of luminescent material, not only maintain the advantages of carbon materials such as low toxicity and good biocompatibility, but also have a luminous range. Incomparable advantages such as adjustable, large two-photon absorption cross-section, high fluorescence quantum efficiency, good photostability, no light flicker, easy functionalization, low price, easy large-scale synthesis, and basically no damage to cells, especially in label...

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Problems solved by technology

The top-down synthesis method, that is, the physical method of exfoliating carbon nanoparticles from larger carbon structures, and then passivating the polymer surface to make them emit light effectively, mainly includes arc discharge, laser ablation, and electrochemical oxidation. , electron beam radiation, etc., such methods often require strict experimental conditions or special energy sources, the cost is high, and the fluorescence quantum yield of carbon quantum dots is low; the bottom-up synthesis method, that is, through pyrolysis or carbonization Suitable precursors directly synthesize fluorescent carbon quantum dots, including combustion method, hydrothermal carbonization method, supported synthesis method, microwave method, ultrasonic method, etc., but because the raw materials selected by this type of method are all non-renewable energy sources and require strict post-processing technology, so it is not conducive to the continuous and large-scale production of carbon quantum dots

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