Core-shell quantum dot material and preparation method thereof

A core-shell quantum dot and quantum dot technology, which is applied in the field of core-shell quantum dot materials and their preparation, can solve the problems of small active area of ​​luminescent materials, reduced fluorescence quantum efficiency, harsh preparation conditions, etc. Good repeatability and high fluorescence quantum efficiency

Inactive Publication Date: 2015-09-16
INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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  • Summary
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AI Technical Summary

Problems solved by technology

In order to obtain fluorescent materials with shorter luminescent wavelengths, since the bandgap width of quantum dots will increase as the size decreases, it is often necessary to control the size of luminescent materials in a smaller range. However, for particles with the same diameter For traditional core-shell materials, too small a core will inevitably lead to a smaller active area of ​​the entire luminescent material
In addition, if the traditional core-shell quantum dot material is used as a fluorescent material, the excessively thick shell layer may cause the excitation light to be absorbed by the shell material and reduce its fluorescence quantum efficiency; if it is used as an electroluminescent active layer light-emitting material, The shell layer will also have a certain hindering effect on the transmission of electron holes to the interior of the quantum dot.
Moreover, to reduce the size of quantum dots to a certain extent, the preparation conditions are often quite harsh.

Method used

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  • Core-shell quantum dot material and preparation method thereof
  • Core-shell quantum dot material and preparation method thereof
  • Core-shell quantum dot material and preparation method thereof

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preparation example Construction

[0037] The invention also discloses a synthesis method of a core-shell quantum dot material, comprising the following steps:

[0038] The first step is to synthesize the CdS quantum dot material as the core layer material. The specific steps include:

[0039] A, sulfur is dissolved in trioctylphosphine (TOP) solution as stock solution;

[0040] B. Dissolve cadmium oxide and zinc acetate in oleic acid, continuously feed nitrogen into the reaction vessel, and heat to 150°C;

[0041] C. After the reactants are completely dissolved, raise the temperature to 230°C, add the above sulfur TOP stock solution, react for 5-10min, and observe that the color of the solution changes from colorless to yellow.

[0042] The second step is to coat the shell material, and the steps include:

[0043] A, a certain proportion of selenium and sulfur are dissolved in TOP, the specific molar ratio can be: 0.1mmol: 3mmol, 0.5mmol: 1.8mmol, 1mmol: 1.3mmol, etc.;

[0044] B. Rapidly inject the mixed s...

preparation Embodiment 1

[0047] Preparation Example 1 The preparation of nuclear layer material

[0048] Synthesizing the CdS quantum dot material as the core layer material, the specific steps include:

[0049] A, the sulfur of 1mmol is dissolved in 1ml trioctylphosphine (TOP) solution as stock solution;

[0050] B. Dissolve 0.4mmol of cadmium oxide and 4mmol of zinc acetate in 15ml of oleic acid, and heat to 150°C;

[0051] C. After the reactants are completely dissolved, raise the temperature to 230°C, add the above-mentioned sulfur TOP stock solution, and react for 5-10 minutes. Observe that the color of the solution changes from colorless to yellow, and the required core layer material is obtained.

preparation Embodiment 2-1

[0052] The cladding of preparation embodiment 2-1 shell material

[0053] Carrying out cladding of the shell material, the steps include:

[0054] A, a certain proportion of selenium and sulfur are dissolved in TOP, the specific molar ratio is 0.1mmol: 3mmol, and the volume of TOP is 1ml;

[0055] B. Rapidly inject the mixed solution of selenium and sulfur into the above reaction solution, continue to react for 30 minutes at 230°C, observe that the color of the solution gradually changes from yellow to brownish yellow, and obtain the required shell material coated quantum dot material.

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Abstract

The invention discloses a core-shell quantum dot structure and a preparation method thereof. The method comprises the following steps: firstly, preparing a core material CdS having a relatively wide band gap width, then coating with a layer of material CdSe having relatively narrow band gap width to be used as a first-layer shell layer, and again coating with wide-band-gap materials CdZnSeS and ZnS as a second-layer shell layer and a third-layer shell layer based on the first-layer shell layer. The new material has the advantages of high fluorescent quantum efficiency and continuous adjustable luminescent spectra relative to a traditional core-shell structural material, has quite good prospects on use no matter as photoluminescence or electroluminescence materials or application in biological fields. The invention also provides a simple method for synthesis of a core-layer material, the process is simple and easy to operate, and the repeatability is good.

Description

technical field [0001] The invention relates to the technical field of photoluminescence and electroluminescence materials, and more specifically relates to a core-shell quantum dot material and a preparation method thereof. Background technique [0002] Compared with organic fluorescent materials, inorganic quantum dot materials have many advantages such as high quantum yield, wide excitation wavelength, good monochromaticity of fluorescence emission spectrum, stable spectral response and long life. However, in semiconductor quantum dots, due to the large number of surface defects and unsaturated dangling bonds in single crystal quantum dots, the fluorescence efficiency is relatively low, so the method of covering the shell layer is usually used to eliminate the influence caused by the surface state. Traditional core-shell fluorescent materials use materials with narrow band gaps as cores, materials with wide band gaps as shells, and core materials with narrow band gaps as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/88C09K11/56C09K11/02
Inventor 李彦沛曲胜春刘孔卢树弟寇艳蕾池丹岳世忠王占国
Owner INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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