Carbon quantum dot with silkworm excrement as raw material as well as preparation method and application of carbon quantum dot

Abstract

The invention discloses a carbon quantum dot which is prepared by taking silkworm excrement as a carbon source. The doping atom percentages of N and O are respectively 0.01 to 30 percent and 0.05 to 5percent and the particle size is 3 to 4 nm. A preparation method of the carbon quantum dot comprises the following steps: firstly, mixing the silkworm excrement with a carbonizer and carrying out microwave reaction (100 to 1000W, 2 to 60 minutes) to obtain a reaction solution; secondly, dialyzing the reaction solution in which insoluble impurities are removed and carrying out freeze drying, thusobtaining a finished product. The mass-volume ratio of the silkworm excrement to the carbonizer is (1 g to 1 mL) to (1 g to 30 mL) in the first step; in addition, the microwave reaction needs to be carried out in a state of stirring or rotating. The carbon quantum dot disclosed by the invention has the advantages of nitrogen modification, good water solubility and good light stability; besides, the carbon quantum dot can be stored at room temperature for one year or above, and can be used as a fluorescent probe which has significant response characteristics to the change of excitation wavelength, pH, metal ion concentration, temperature and solvent polarity; the carbon quantum dot provides a broad application prospect for the field of biological detection and imaging in the future.

Description

technical field [0001] The invention relates to the technical field of carbon nanomaterials, more specifically, to a carbon quantum dot using silkworm excrement as a raw material, its preparation method and application. Background technique [0002] Compared with the well-known and commercialized quantum dots, carbon quantum dots (Carbon dots, referred to as CDs) have similar characteristics, such as high luminous brightness, adjustable size, adjustable fluorescence emission wavelength, photobleaching resistance, etc. In addition, CDs do not contain toxic elements, and their use does not bring inherent toxic burdens to ecosystems or organisms, making them ideal materials for in vivo bioanalysis. [0003] So far, CDs have attracted great attention and shown great application potential in energy conversion and storage, bioimaging, sensors, bioprobes, and various other fields. Since Sun and co-workers first prepared CDs by laser ablation in 2006, many studies have focused on t...

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Problems solved by technology

[0006] The Chinese patent No. 201710755244.4 discloses a method for preparing fluorescent carbon dots using silkworm excrement as a raw material, which is to conduct high-temperature direct carbonization or hydrothermal carbonization on the cleaned silkworm excrement at a certain temperature and for a certain period of time, and then purify To obtain fluorescent carbon dot powder, this method takes a long time, and the purification process of the obtained fluorescent carbon dots is relatively complicated, and the carbonization effect of silkworm excrement is incomplete and uneven. Therefore, it is necessary to use ultrasonic means to further disperse and separate the obtained products. In practice, the yield of carbon quantum dots prepared by this method is too low, basically below 20%, and a large amount of impurities with incomplete carbonization are produced at the same time. The prepared carbon quantum dots may be aggregated and the size is too large to show quantum properties.

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