Quantum dots and preparation method thereof

A quantum dot and seed crystal technology, applied in the field of nano-semiconductor material preparation, can solve problems such as quantum dot lattice defects

Active Publication Date: 2021-04-20
CHINA BEIJING BEIDA JUBANG SCI & TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Therefore, the technical problem to be solved by the present invention is that there is still a lattice mismatch between the quantum dot core and the shell in the prior art, resulting

Method used

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  • Quantum dots and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0069] This embodiment provides a method for preparing quantum dots, the specific steps are as follows:

[0070] 1) Preparation of ZnCdSe seed solution:

[0071] Weigh 0.05mmol of cadmium oxide and 0.5mmol of zinc oxide into a 25mL three-necked flask, add 2mL of oleic acid and 3mL of octadecene, vacuumize and heat to 150°C until the solution is clear, and blow nitrogen to obtain the first cationic precursor. Under the protection of nitrogen, the temperature was raised to 310°C, and 0.04mL of the first anion precursor was quickly added to the reaction system with stirring. After 15 minutes of reaction, 1mL of oleic acid was quickly added, and the emission wavelength was 610nm, and the half-peak width was 35nm. ;

[0072] 2) Preparation of ZnCdSe-ZnSe quantum dot nuclear solution:

[0073] Slowly add 0.06mL of the first anion precursor to the above seed solution at a rate of 0.144mL / h, dropwise for 25min, start dropping from 310°C to 325°C at a rate of 3°C / min, dropwise Conti...

Embodiment 2

[0081] This embodiment provides a method for preparing quantum dots, the specific steps are as follows:

[0082] 1) Preparation of ZnCdSe seed solution:

[0083] Weigh 0.05mmol of cadmium oxide and 0.5mmol of zinc oxide into a 25mL three-necked flask, add 2mL of oleic acid and 3mL of octadecene, vacuumize and heat to 150°C until the solution is clear, and blow nitrogen to obtain the first cationic precursor. Under the protection of nitrogen, the temperature was raised to 310°C, and 0.06mL of the first anion precursor was quickly added to the reaction system with stirring. After 15 minutes of reaction, 1mL of oleic acid was quickly added, and the emission wavelength was 590nm, and the half-peak width was 34nm. ;

[0084] 2) Preparation of ZnCdSe-ZnSe quantum dot nuclear solution:

[0085] Slowly add 0.04mL of the first anion precursor to the above seed solution at a rate of 0.096mL / h, dropwise for 25min, start dropping from 310°C to 325°C at a rate of 3°C / min, dropwise Conti...

Embodiment 3

[0093] This example provides a method for preparing quantum dots, and the difference from Example 2 is that the 0.06mL first anion precursor injected in the first step in Example 2 is replaced with 0.08mL, and the rest of the conditions remain unchanged;

[0094] Among them, the emission peak position and half-peak width of the ZnCdSe seed crystal are 571nm and 33nm, respectively;

[0095] Among them, the emission peak position and half-peak width of ZnCdSe-ZnSe quantum dot core are 562nm and 23nm respectively;

[0096] Among them, the emission peak position and half-peak width of ZnCdSe-ZnSe / ZnSe quantum dots are 561nm and 25nm respectively;

[0097] The emission peak position, half-peak width and quantum efficiency of the ZnCdSe-ZnSe / ZnSe / ZnS quantum dot obtained after precipitation and drying are 560nm, 24nm and 90% respectively, and its structure is as follows: figure 1 shown.

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Abstract

The invention discloses a preparation method of quantum dots, wherein the preparation method comprises the steps: preparing ZnCdSe seed crystals, growing a ZnSe transition layer on the ZnCdSe seed crystals, and sequentially coating the ZnSe transition layer with a ZnSe shell layer and a ZnS shell layer. The invention also discloses the quantum dots prepared by the preparation method. Through the arrangement of the ZnSe transition layer, the relationship between a core and the shell layers is consolidated, the transition between the core and each shell layer is effectively controlled, and the defects between crystal lattices are reduced; the formation of other seed crystals in the quantum dots is inhibited through fatty acid so as to control the components, size and uniformity of the seed crystals of the quantum dots, anions are supplemented to carry out growth nucleation of the seed crystals, a quantum dot core structure with the ZnSe transition layer on the surface is formed, and then epitaxial growth of the ZnSe shell layer and the ZnS shell layer are sequentially carried out; lattice stress between components of the mixed crystal structure core and lattice stress between the core and the shell are reduced, and the prepared quantum dots are adjustable in peak position in visible light, narrow in half-peak width and high in quantum efficiency.

Description

technical field [0001] The invention relates to the field of preparation of nano-semiconductor materials, in particular to a quantum dot and a preparation method thereof. Background technique [0002] Quantum dots can also be called nanocrystals, and the particle size is generally between 2 and 20 nanometers, which is about one hundred thousandth of the thickness of a hair. Quantum dots can emit light after being excited by light, electricity, etc., and the emission wavelength can be adjusted by changing the size, so that it has a continuously distributed emission spectrum. Based on the remarkable quantum effect and narrow peak width, quantum dots have broad application prospects in the fields of solar cells, display devices, lighting, and biomarkers. [0003] Common quantum dots are mostly core-shell structures, that is, CdSe, CdTe, CdS, ZnSe, InP, etc. are usually used as cores, and CdS, ZnSe, ZnS with relatively larger band gaps are used as shell layers. The lattice mis...

Claims

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Application Information

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IPC IPC(8): C09K11/02C09K11/88
Inventor 赵治强高晓斌阴德贺
Owner CHINA BEIJING BEIDA JUBANG SCI & TECH CO LTD
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