Preparation method of fluorescent nitrogen-enriched quantum dots as well as products and application of quantum dots

A quantum dot and fluorescence technology, which is applied in the preparation of fluorescent nitrogen-rich quantum dots and its products and applications, can solve the problems of low quantum efficiency of carbon dots, complex components, difficult to repeat the reaction, etc., to achieve biological safety and biophase Good capacitance, excellent fluorescence properties, and high quantum efficiency

Inactive Publication Date: 2015-06-10
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The reaction conditions in the above carbon quantum dot synthesis methods are all severe and require strong acid or strong base oxidation, and the quantum efficiency of unmodified carbon dots is low, the reaction raw materials are not single enough, and the reaction is difficult to repeat, etc.
In addition, the starting materials in the synthesis of carbon quantum dots are graphite or organic molecules and the components are complex, which adds great difficulty to the study of the formation mechanism of carbon dots, which needs to be improved

Method used

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  • Preparation method of fluorescent nitrogen-enriched quantum dots as well as products and application of quantum dots
  • Preparation method of fluorescent nitrogen-enriched quantum dots as well as products and application of quantum dots
  • Preparation method of fluorescent nitrogen-enriched quantum dots as well as products and application of quantum dots

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Example 1 Synthesis of reaction materials

[0052] Synthesis of 2-azidoimidazole

[0053] 2-azidoimidazole sulfate (3.30g, 25.0mmol) was dissolved in HCl aqueous solution (5.0mol / L, 20mL), cooled to 0℃ in an ice water bath, and then NaNO was added dropwise 2 (1.73g, 25.1mmol) aqueous solution and NaN 3 (1.63g, 25.1mmol) in water. The mixed solution was slowly raised from 0°C to room temperature, and then stirred and reacted at room temperature for 20 hours. Stop the reaction and use solid NaHCO 3 After adjusting the pH to neutral, extract with ethyl acetate (3×50mL), anhydrous Na 2 SO 4 Dry, filter, and spin-dry the filtrate to obtain a yellow powder. The obtained yellow powder was purified by silica gel column (developing solvent petroleum ether: ethyl acetate = 1:1), and finally 2.31 g of yellow crystal solid was obtained with a yield of 84.7%. 1 HNMR(DMSO)δ[ppm]6.88(s, 1H); 13 CNMR (DMSO) δ [ppm] 139.91, 127.33, 116.24. FTIR(cm -1 )-N 3 2132cm -1 .

[0054] Synthesis of ...

Embodiment 2

[0061] Example 2 Preparation of fluorescent nitrogen-rich quantum dots

[0062] Method 1: A methanol solution (75ml) of 2-azidoimidazole (0.360g) was stirred at 70°C for 24 hours. After the reaction, the methanol was removed by rotary evaporation under reduced pressure and dried. The residue was washed with ethyl acetate for 3 to 4 times until the reaction material (2-azidoimidazole) disappeared, and then dried; the dried product was re-dispersed with water, and the aqueous solution was passed through 0.8μm , 0.45μm and 0.22μm filter membranes, the filtrate was vacuum freeze-dried to obtain 0.120g red-brown solid, the crude product yield was 33%. The obtained crude nitrogen-rich quantum dots are further passed through Sephadex G-25 chromatographic column (the inner diameter of the column is 1.5cm, the height of the gel column is 20-30cm, and the amount of sample <100mg, the flow rate is about 0.2ml / min) purification, the developing solvent is water: methanol = 95:5, according to ...

Embodiment 3

[0067] Example 3 Preparation of fluorescent nitrogen-rich quantum dots under different reaction temperature conditions

[0068] By changing the reaction temperature of carbon quantum dots from 2-azidoimidazole, nitrogen-rich quantum dots with different fluorescence properties can also be obtained.

[0069] After reacting the methanol solution of 2-azidoimidazole at 50℃ for 24, the obtained crude nitrogen-rich quantum dots have similar spectroscopic properties to N-dot3, and the emission peak is fixed at about 515nm, such as figure 2 (a). When the reaction temperature is changed to 100°C and other conditions remain unchanged, the obtained crude nitrogen-enriched quantum dots have similar spectral properties to N-dot1. With the change of excitation wavelength, the emission peak changes, such as figure 2 (c). Therefore, by controlling the reaction temperature of 2-azidoimidazole to produce carbon quantum dots, the progress of the reaction and the fluorescence properties of the obtai...

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Abstract

The invention discloses a preparation method of fluorescent nitrogen-enriched quantum dots (N-dots) as well as products and an application of the quantum dots. The preparation method comprises the steps: (1) dissolving a compound as shown in a formula I in a solvent such as methanol or water to carry out heating reaction or illumination reaction; and (2) removing the solvent in a reaction product, and drying; removing a reaction raw material in a drying product, drying again, and dispersing again by adding water to obtain an aqueous solution; filtering the aqueous solution by using a filtering membrane, and drying a filtrate to obtain crude nitrogen-enriched quantum dots; and separating three types of nitrogen-enriched quantum dots different in optical properties from the crude nitrogen-enriched quantum dots by using an exclusion chromatography. The highest nitrogen content of the nitrogen-enriched quantum dots can be up to 34.48%, the particle sizes of the nitrogen-enriched quantum dots are less than 10nm, and the nitrogen-enriched quantum dots are good in fluorescence and water solubility and can be processed into fluorescent ink or biocompatible dye so as to be applied in various research fields. According to the preparation method, the nitrogen-enriched quantum dots with good fluorescent property are prepared by using single small molecules as initialing materials under mild conditions. The preparation method is good in repeatability, the reaction process can be artificially controlled, and the quantum efficiency is high.

Description

Technical field [0001] The invention relates to a method for preparing a novel quantum dot and its product, in particular to a method for preparing a fluorescent nitrogen quantum dot with high nitrogen content and a quantum dot product prepared by the method. The invention further relates to the high nitrogen content The use of fluorescent carbon quantum dots in the preparation and application of fluorescent labeling materials in research fields such as life science, material science, physical science, and chemical science belongs to the field of preparation and application of quantum dots. Background technique [0002] In recent years, quantum dots have attracted more and more attention from researchers. Quantum dots have a small particle size, generally ranging from 1 to 20 nm, and their electrons and holes are quantum confined, so they exhibit many unique physical properties, of which their excellent optical properties are the most prominent. Because quantum dots have unique ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/65C09K11/06D06P1/00C09D11/17
Inventor 汤新景陈修贤
Owner PEKING UNIV
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