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Core-shell quantum dot, preparation method thereof and quantum dot photoelectric device

A technology of core-shell quantum dots and optoelectronic devices, applied in chemical instruments and methods, nano optics, luminescent materials, etc., can solve problems such as poor monodispersity, reduced efficiency, and poor resistance to water and oxygen, and achieve reduced defect states and stable The effect of good sex and few influencing factors

Pending Publication Date: 2019-07-26
NANJING TECH CORP LTD
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  • Claims
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Problems solved by technology

[0004] At present, the general method of coating the CdZnS shell layer is to inject the S precursor into the mixed solution of the Cd precursor and the Zn precursor to form a CdZnS layer, but the CdSe / CdZnS core-shell quantum dots obtained by this method will be in the subsequent When continuing to coat ZnS, the fluorescence half-peak width becomes wider, the efficiency decreases, the monodispersity of size and morphology is poor, and the resistance to water and oxygen is very poor.

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  • Core-shell quantum dot, preparation method thereof and quantum dot photoelectric device
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  • Core-shell quantum dot, preparation method thereof and quantum dot photoelectric device

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preparation example Construction

[0030] In the prior art, the step of coating the CdZnS shell on the CdSe quantum dot is to inject the sulfur precursor into the mixed solution of the cadmium precursor and the zinc precursor to react. The inventors have found that since the reactivity of the cadmium precursor is higher than that of the zinc precursor, the CdZnS shell layer has less cadmium atom content as it moves outward. The CdZnS shell layer coated in the prior art is equivalent to CdS / CdZnS containing a small amount of cadmium. / Thicker ZnS, which leads to thicker ZnS on the outside of the CdZnS shell, which increases the defect states of the CdZnS shell and deteriorates the purity of the crystal form. The coating efficiency of the shell layer is low, and the obtained core-shell quantum dots have a narrow half-width of fluorescence, a decrease in fluorescence efficiency, and poor resistance to water and oxygen. In order to solve this problem, the present invention provides a method for preparing core-shell...

Embodiment 1

[0072] Coating of the middle shell:

[0073] (1) Add 4mmol of zinc acetate, 0.2mmol of cadmium acetate, 4.4g of oleic acid and 15mL of ODE into a 100mL three-neck flask, and at 200°C, pass inert gas to exhaust for 30 minutes, and then inject the purified first excitons For a CdSe quantum dot solution with an absorption peak of 570nm and an absorbance of 50, raise the temperature to 300°C;

[0074] (2) Then quickly inject 2mL of S-TBP solution with a concentration of 0.625mmol / mL, react for 1 minute, inject 0.25mL of cadmium oleate solution with a concentration of 0.2mmol / mL, continue to react for 2 minutes, stop the reaction and cool down rapidly, and purify The obtained CdSe / CdZnS was dissolved in 1 mL of ODE.

[0075] Covering of the shell layer:

[0076] (3) Weigh basic zinc carbonate (0.66g, 1.2mmol), 2.8g oleic acid, and 10mL ODE into a 100mL three-necked flask, exhaust with inert gas for 10 minutes, raise the temperature to 280°C, and obtain a clear solution, Then inj...

Embodiment 2

[0079] The difference between embodiment 2 and embodiment 1 is that the addition amount of cadmium oleate is different in step (2).

[0080] Step (2) among the embodiment 2 is: then inject 2mL concentration rapidly and be the S-TBP solution of 0.625mmol / mL, react for 1 minute, inject 0.1mL concentration and be the cadmium oleate solution of 0.2mmol / mL, continue to react for 2 minutes, Stop the reaction and cool down quickly, purify the obtained CdSe / CdZnS and dissolve it in 1 mL of ODE.

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Abstract

The invention discloses a core-shell quantum dot, a preparation method thereof and a quantum dot photoelectric device. The preparation method of the core-shell quantum dot includes the following steps: S1, adding a quantum dot core to a solution comprising first cadmium precursors and first zinc precursors to form a first mixed solution; S2, adding first anion precursors to the first mixed solution, and coating the quantum dot core with a middle shell layer; S3, adding a purified core-shell quantum dot to a solution comprising second zinc precursors to obtain a second mixed solution; S4, adding second anion precursors to the second mixed solution for reaction, and coating the core-shell quantum dot with an outer shell layer. The preparation method is further characterized by at least one of A, B and C: A, in the step S2, after the first anion precursors are added, a first certain amount of second cadmium precursors are added for reaction; B, a step S3' is included between the step S3 and the step S4, and a second certain amount of third cadmium precursors are added to the second mixed solution; C, in the step S4, a third certain amount of the third cadmium precursors are added to the second mixed solution for reaction.

Description

technical field [0001] The invention relates to the technical field of quantum dot materials, in particular to a core-shell quantum dot, a preparation method thereof, and a quantum dot photoelectric device. Background technique [0002] In the past two decades, quantum dot synthesis chemistry has mainly focused on the monodisperse control of size and morphology and how to improve the fluorescence quantum yield. However, in order to make quantum dots as a class of excellent luminescent and photoelectric materials, the more important goal in synthesis is to obtain quantum dots with high environmental stability, that is, to reduce the impact of the environment, especially water and oxygen, on the optical and electrical properties of quantum dots as much as possible. The influence of nature, which has a great role in promoting the academic and applied research of quantum dots. [0003] For nuclear quantum dots of a single size, due to the large specific surface area of ​​quantu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/88B82Y20/00B82Y40/00
CPCB82Y20/00B82Y40/00C09K11/883
Inventor 周健海何洋
Owner NANJING TECH CORP LTD
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