Red light emitting carbon quantum dots and household microwave preparation method thereof

A carbon quantum dot, household technology, applied in chemical instruments and methods, nano-carbon, nano-optics, etc., can solve the limitations of the application progress of red light carbon quantum dots, the low quantum efficiency of red light carbon quantum dots, and the difficulty in controlling the size of the quantum dots. products and other problems, to achieve the effects of simple and environmentally friendly materials, low requirements for reaction conditions, and simple methods

Active Publication Date: 2019-04-19
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The main preparation methods are hydrothermal method and microwave method. Among them, the carbon quantum dots obtained by the hydrothermal method are relatively pure and have high quantum efficiency, but the reaction conditions are harsh and the yield is low; the microwave method is extremely simple and environmentally friendly. But it is difficult to control the size and more by-products
Most of the microwave methods are microwave reactors, which can perform microwave reactions under high temperature and high pressure, and the equipment is relatively expensive.
After years of research, the quantum efficiency of blue-light carbon quantum dots can reach more than 80%, and the quantum efficiency of green-light carbon quantum dots can reach more than 50%, but the quantum efficiency of red-light carbon quantum dots has been at a low level.
Moreover, most of the red-light carbon quantum dots exhibit low excitation efficiency, especially blue-green luminescence under near-ultraviolet light excitation, which greatly limits the application progress of red-light carbon quantum dots.

Method used

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  • Red light emitting carbon quantum dots and household microwave preparation method thereof
  • Red light emitting carbon quantum dots and household microwave preparation method thereof
  • Red light emitting carbon quantum dots and household microwave preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0040] The present invention provides the red light-emitting carbon quantum dots and their household microwave preparation method, including the following steps (see figure 1 ):

[0041] Take 1.25 g of ammonium citrate in a 50 mL beaker, then measure 25 mL of glycerol and pour it into the beaker, heat and stir the mixture, the heating temperature is controlled at 100 °C, and the heating and stirring time is 25 min, until it becomes cloudy The mixture becomes a homogeneous transparent solution;

[0042] Add 3 mL of formamide into the above solution, stir evenly to form a mixed solution;

[0043] Move the obtained mixed solution into a microwave oven, and heat the reaction for 4 minutes under the condition of a power of 900 W, and the solution turns from colorless to dark reddish brown rapidly;

[0044] After it was naturally cooled to room temperature, the reaction product was dispersed in absolute ethanol, and the volume ratio of absolute ethanol to the reaction product was ...

Embodiment 2

[0047] The present invention provides the red light-emitting carbon quantum dots and their household microwave preparation method, comprising the following steps:

[0048] Take 2.5 g of ammonium citrate in a 50 mL beaker, then measure 25 mL of glycerol and pour it into the beaker, heat and stir the mixture, control the heating temperature at 120 °C, and heat and stir for 25 min until The turbid mixture becomes a homogeneous transparent solution;

[0049] Add 1mL of formamide into the above solution, stir evenly to form a mixed solution;

[0050] Move the obtained mixed solution into a microwave oven, and heat the reaction for 10 minutes under the condition of power 1200 W, and the solution turns from colorless to dark reddish brown rapidly;

[0051] After it was naturally cooled to room temperature, the reaction product was dispersed in absolute ethanol, the volume ratio of the amount of absolute ethanol to the reaction product was 1:3 (the amount of absolute ethanol was 6mL,...

Embodiment 3

[0054] The present invention provides the red light-emitting carbon quantum dots and their household microwave preparation method, comprising the following steps:

[0055] Take 0.5 g of ammonium citrate in a 50 mL beaker, then measure 25 mL of glycerol and pour it into the beaker, heat and stir the mixture, the heating temperature is controlled at 80 ° C, and the heating and stirring time is 20 min until the The turbid mixture becomes a homogeneous transparent solution;

[0056] Add 5 mL of formamide to the above solution, stir well to form a mixed solution;

[0057] The obtained mixed solution was transferred into a microwave oven, and heated for 2 min under the condition of power 800 W, the solution changed from colorless to dark reddish brown rapidly; after it was naturally cooled to room temperature, the reaction product was dispersed in absolute ethanol, without The volume ratio of water to ethanol to the reaction product was 1:9 (the volume of absolute ethanol was 2 mL,...

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Abstract

The invention discloses red light emitting carbon quantum dots and a household microwave preparation method thereof. The method comprises the following steps: dispersing ammonium citrate in a glycerolsolvent, heating and stirring to form a solution, adding formamide, and uniformly stirring; putting the mixture into a household microwave oven for heating reaction, cooling to room temperature, adding absolute ethyl alcohol, uniformly mixing, centrifuging to obtain a precipitate, dispersing the precipitate in absolute ethyl alcohol, filtering by a filter head to obtain preliminarily purified carbon quantum dots, and carrying out silica gel column chromatography for secondary purification to obtain a red light emission carbon quantum dot solution. The emission wavelength of the red quantum dot solution is 650 nm, and the fluorescence quantum efficiency reaches 23%, the red light emission carbon quantum dot solution has fluorescence excitation independent luminescence characteristics, andis still in red light emission state under near ultraviolet excitation. The method provided by the invention has the advantages of operation simplicity, environmental protection, low cost, high yield,and the like, and the obtained carbon quantum dots are uniform in size, high in purity, stable in fluorescence, non-toxic and pollution-free, and have important application value in the aspects of biomedicine and optoelectronic devices.

Description

technical field [0001] The invention relates to the technical field of carbon nanomaterials, in particular to a red light-emitting carbon quantum dot and a household microwave preparation method thereof. Background technique [0002] Fluorescent carbon quantum dots are a new type of fluorescent nanomaterials (with a size less than 10 nm), which have the characteristics of high photobleaching stability, non-toxic biocompatibility, excellent surface functional groups, and easy preparation. Since the discovery of carbon quantum dots in 2004, it has attracted widespread attention as a promising substitute for cadmium-based quantum dots, and has been widely used in drug delivery, biomarkers, ion detection, and light-emitting diode lighting. [0003] At present, there are two main methods for preparing carbon quantum dots at home and abroad, top-down method and bottom-up method. The top-down method mainly includes electrochemical method, laser etching method, high temperature and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/65C01B32/15B82Y20/00B82Y40/00H01L33/50
CPCH01L33/504C09K11/65B82Y20/00B82Y40/00C01B32/15
Inventor 章勇任花蓝栩砚杨欣
Owner SOUTH CHINA NORMAL UNIVERSITY
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