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Method for preparing silicon dioxide-coated quantum dots

A technology of silicon dioxide and quantum dots, applied in the field of quantum dots, which can solve the problems of complicated operation, many experimental steps, and large size of quantum dots.

Active Publication Date: 2010-06-02
CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The silanization method disclosed in the above-mentioned patent has many experimental steps, and the operation is cumbersome and difficult to control. Moreover, the size of the obtained quantum dots is relatively large. Generally, the particle size can only ensure the uniformity of the size when the particle size is several hundred nanometers.

Method used

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Examples

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preparation example Construction

[0025] A method for preparing silicon dioxide-coated quantum dots, comprising:

[0026] Dispersing quantum dots with a CdSe / CdS core-shell structure in cyclohexane to obtain a first mixed solution;

[0027] Adding n-hexane, surfactant and ethyl orthosilicate to the first mixed solution to obtain a second mixed solution;

[0028] Adding ammonia water to the second mixed solution for reaction;

[0029] The reaction product was precipitated and separated to obtain silica-coated quantum dots.

[0030] According to the present invention, there is no special limitation on the preparation method of CdSe / CdS core-shell structure quantum dots, for example, it can be prepared according to the method of document Adv.Mater.[J], 2005, 17, 176-179, namely: First mix cadmium oxide and tetradecyl carboxylic acid, preferably heated to about 210°C, and react until a colorless and transparent solution is formed. After cooling, the crude product is recrystallized with toluene to obtain cadmium ...

Embodiment 1

[0044] Add 1.926g of cadmium oxide and 7.6g of tetradecyl carboxylic acid into the flask, and heat to 210°C under magnetic stirring, and react until a colorless and transparent solution is formed. After the reaction was cooled, the crude product was recrystallized twice from toluene to obtain cadmium tetradecylcarboxylate (Cd-MA).

[0045] Add 0.1134g of Cd-MA, 1.0mL of oleic acid and 10mL of toluene into the polytetrafluoroethylene (Teflon) liner of a stainless steel autoclave with a capacity of 30mL, and heat at a temperature of 80-100°C until a colorless and transparent solution, and then cooled to room temperature. Dissolve 0.0125g of selenourea in 10mL of nitrogen-saturated water, and then add the selenourea aqueous solution into the above-mentioned autoclave. After sealing the autoclave, put it into an oven at 180°C to react for 18 minutes. After the predetermined reaction time, the autoclave was taken out and cooled to room temperature. The upper organic phase was ta...

Embodiment 2

[0048] Take 0.1 mL of the organic phase toluene solution of CdSe / CdS prepared in Example 1;

[0049] Purify the organic phase toluene solution of the CdSe / CdS with methanol to obtain CdSe / CdS quantum dots, and then disperse into 7.5mL of cyclohexane to obtain a microemulsion;

[0050] Add 2mL of n-hexane, 2mL of TritonX-100 and 100μL of TEOS to the microemulsion, put them together into a 50mL round-bottomed flask, and magnetically stir for 30min to obtain a mixed solution;

[0051] Add 250 μL of ammonia water to the mixture, and react for 24 hours at room temperature at 20°C in the dark;

[0052] After the reaction is finished, add a large amount of acetone to precipitate the reaction product, then centrifuge and discard the supernatant;

[0053] Wash the product twice with ethanol, butanol, and water respectively to obtain silica-coated CdSe / CdS / quantum dots, and ultrasonically disperse them into ethanol for testing. The diameter is 23.0±2.8nm and the luminous efficiency is ...

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Abstract

The invention provides a method for preparing silicon dioxide-coated quantum dots. The method comprises the following steps of: dispersing CdSe / CdS core-shell structural quantum dots into cyclohexane to obtain first mixed liquid; adding n-hexane, surfactant and ethyl orthosilicate into the first mixed liquid to obtain second mixed liquid; adding ammonia water into the second mixed liquid to carry out reaction; and depositing and separating a reaction product to obtain the silicon dioxide-coated quantum dots. The method firstly disperses the CdSe / CdS core-shell structural quantum dots into the cyclohexane to obtain the first mixed liquid, and then adds the n-hexane into the first mixed liquid serving as a dispersant. Since the n-hexane has similar polarity to the cyclohexane, the quantum dots can be dispersed into the n-hexane well. SiO2 formed by the hydrolysis of the ethyl orthosilicate can be coated on the quantum dots to the largest extent to obtain SiO2-coated CdSe / CdS core-shell structural quantum dots with uniform particle size. Compared with the prior art, the method for preparing the silicon dioxide-coated quantum dots has the advantages of few experimental procedures, simple operation and easy control.

Description

technical field [0001] The invention relates to the technical field of quantum dots, in particular to a method for preparing silicon dioxide-coated quantum dots. Background technique [0002] Quantum dots generally refer to nanoparticles with radii smaller than or close to their Bohr excitonic radii. The research on quantum dot materials is a research involving interdisciplinary fields. In addition to semiconductor quantum dots, there are also quantum dots of metals and other substances. The quantum dots mentioned in this article refer to semiconductor quantum dots unless otherwise specified. Semiconductor quantum dots are aggregates of nanoscale atoms and molecules, and the general particle size ranges from 2-40nm. Due to the characteristics of adjustable emission wavelength and high quantum yield, quantum dots have broad application prospects in the fields of optoelectronic devices and life sciences. Quantum dots are divided into single quantum dots and quantum dots with...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/88
Inventor 马晓波聂伟姬相玲
Owner CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES
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