Method for preparing yellow or green silicon quantum dots

Abstract

The invention discloses a method for preparing yellow or green silicon quantum dots. The method comprises the following steps: (1) dispersing a silicon source, a first reducing agent and a second reducing agent into ultrapure water; then stirring under the protection of protective gas to obtain a mixed solution; (2) heating the mixed solution obtained by step (1) in a reaction container and reacting to obtain a silicon quantum dot solution; and (3) mixing the silicon quantum dot solution obtained by step (2) and an organic reagent and then centrifuging and drying to obtain solid silicon quantum dots. Based on a synergistic effect of the first reducing agent and the second reducing agent, the yellow or green silicon quantum dots with the high quantum yield are synthesized in one step through a simple water-phase method and the silicon quantum dots with different emission wavelengths can be synthesized through adjusting the temperature of heating reaction; and the quantum yield of the green silicon quantum dots is 38.31 percent and the quantum yield of the yellow silicon quantum dots is 29.36 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 silicon quantum dots. Background technique [0002] Silicon quantum dots are a new type of silicon 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. Optoelectronics, catalysis and sensing have broad application prospects. There are various methods for preparing silicon quantum dots, but most methods synthesize silicon quantum dots with blue fluorescence. Due to the poor penetration of short-wavelength (blue) silicon quantum dots to tissues, the optical imaging of deep tissues in the body is limited. In addition, almost all biological tissues will produce autofluorescence for short-wavelength visible light, which interferes with the imaging effect, while long-w...

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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 silicon quantum dots, wherein the overall flow process of the preparation method, and the conditions and parameters used in key synthesis reactions ( Including the type and proportion of reaction raw materials, etc.) to improve, compared with the prior art, it can effectively solve the problem of difficult preparation of yellow or green silicon quantum dots. Most of the methods in the prior art prepare blue silicon quantum dots, only A small number of methods for preparing yellow or green silicon quantum dots, but since these prior art methods for preparing yellow or green silicon quantum dots still have the problems of low quantum yield, complicated operation, and high requirements for equipment, the present invention is based on reducing The synergistic effect of agent 1 (i.e. the first reducing agent) and reducing agent 2 (i.e. the second reducing agent), using silicon source raw materials, through a simple aqueous phase method to synthesize green or yellow silicon quantum dots with high quantum yield in one step, and Preferably through the overall coordination between the various parameters of the preparation method, especially by adjusting the temperature of the heating reaction, yellow silicon quantum dots or green silicon quantum dots can be produced separately (of course, the preparation method of the present invention can also obtain yellow silicon quantum dots and green silicon quantum dots. Quantum dot hybrid product)

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