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High fluorescence efficiency core-shell structure cadmium-free quantum dots and its preparation method and use

A core-shell structure and quantum dot technology, which is applied in the field of preparation of core-shell structure cadmium-free quantum dots, can solve the problems of high preparation method and process requirements, poor stability, low luminous efficiency of blue quantum dots, etc., so as to improve the quantum dots. Efficiency and stability, the effect of reducing surface defects

Active Publication Date: 2020-04-17
南京紫同纳米科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are still the following problems in the application of blue quantum dots in white LEDs or electroluminescent display devices: (1) The nanometer radius of the quantum dots is smaller than that of red and green quantum dots, which requires higher preparation methods and processes, so The synthesized quantum dot material is less stable than the green or red quantum dot material; (2) Due to the limitation of the synthesis method, the luminous efficiency of the blue quantum dot is low, and the literature shows that the blue quantum dot of the InP system Luminous efficiency does not exceed 50%

Method used

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  • High fluorescence efficiency core-shell structure cadmium-free quantum dots and its preparation method and use
  • High fluorescence efficiency core-shell structure cadmium-free quantum dots and its preparation method and use
  • High fluorescence efficiency core-shell structure cadmium-free quantum dots and its preparation method and use

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Experimental program
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Effect test

Embodiment 1

[0050] Synthesis of InP / ZnS Blue Quantum Dots with a ZnS Shell Using ZnI2 to Control the Reaction Speed

[0051] According to the ratio of 2.4 mmol tris (dimethylamino) phosphine ((DMA) 3P): 1 milliliter of oleylamine (OAm, 6 mmol) to prepare the P-containing precursor solution: the system is evacuated, stirred and Heating to 80° C. and maintaining the reaction temperature for 30 minutes to obtain tris(dioleylamino)phosphine. Add 0.34 mmol of indium chloride tetrahydrate and 2.2 mmol of zinc iodide into 5 ml of oleylamine, stir to defoam, and heat to 150°C, maintain the temperature for 1 hour, and form an In-containing precursor after completely dissolving . Vacuum defoaming of the precursor solution by nitrogen gas was repeated 3 times, and then heated to 200°C. Then, 1.45 ml of P-containing precursor solution was quickly injected, and the temperature was maintained for 20 minutes to generate InP quantum dot cores. Next, inject 1.05 milliliters of n-dodecanethiol and 6 mil...

Embodiment 2

[0053] Synthesis of InP / ZnS Blue Quantum Dots with a ZnS Shell Using Different Concentrations of ZnI2 to Control the Reaction Speed

[0054] Embodiment 2 The method for synthesizing InP / ZnS blue quantum dots with core-shell structure is the same as that of Embodiment 1, the difference being that the amount of ZnI2 added in Embodiment 1 is changed to 1.65 millimoles. The blue quantum dot with InP / ZnS core-shell structure obtained in Example 2 has a diameter of 5.33±0.44nm, an emission spectrum peak of 489nm excited by 395nm ultraviolet light, and a luminous quantum efficiency of 37%.

Embodiment 3

[0060] Synthesis of InP / ZnS blue quantum dots with two-layer ZnS shells using ZnI2 to control the reaction rate

[0061] Take 20 ml of the quantum dot toluene mixture obtained in Example 1, centrifuge at a speed of 10000 rpm, then add 40 ml of ethanol to further settle the quantum dots, remove the supernatant, and add 5 ml of octadecene. Then the system was heated to 150° C., stirred and defoamed for 1 hour, and the second layer of ZnS was ready to be coated. Inject 0.2 milliliters of n-dodecanethiol and 1.5 milliliters of the above-mentioned octadecene solution of zinc stearate in sequence, then heat the system to 300° C., and react at this temperature for 0.5 hours. Next, the above reaction solution was injected into 16 ml of toluene to terminate the reaction. The InP / ZnS thin-core thick-shell blue quantum dot obtained in Example 3 has a diameter of 6.68±0.46nm, an emission peak of 477nm excited by 395nm ultraviolet light, and a luminous quantum efficiency of 76%.

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Abstract

The present invention discloses high fluorescent efficiency core-shell structure cadmium-free quantum dots and a preparation method and use thereof. When in preparing, a precursor solution containing In is prepared, ZnX2 is introduced into the precursor solution, X is one ore a mixture of a plurality of substances of Cl, Br and I, the precursor solution is heated to achieve an inert environment of the system; a P-containing precursor is injected into the precursor solution containing the In for reaction to generate InP quantum dot nuclei; a ZnS precursor solution is added in the reaction, first ZnS shells are directly synthesized on the InP quantum dot nuclei; second ZnS shells, third ZnS shells and more ZnS shells are synthesized to obtain a thin-core thick-shell structure. The thin-core thick-shell structure InP / ZnS cadmium-free quantum dot material obtained by the method emits blue light after being excited by high-energy UV light, has a luminous efficiency up to 76%, has water and oxygen stability, and the like, and can be used in a light emitting diode to emit the blue light after being electrified.

Description

technical field [0001] The invention relates to the field of manufacturing quantum dot materials used in light-emitting diodes and electroluminescent display devices, in particular to a preparation method and application of a core-shell structure cadmium-free quantum dot. Background technique [0002] Semiconductor nanocrystal materials with quantum effects have characteristics such as high light absorption, high fluorescence efficiency upon stimulation, narrow half-peak width, and adjustable peak position, and have been used in solar energy, photoelectric detection, light-emitting devices, and fluorescent biological detection. . However, there are still great technical challenges in the application of quantum dot materials to electroluminescent light-emitting diodes and corresponding display devices, especially blue light-emitting diodes. The quantum dot materials currently used in electroluminescent diodes are mainly semiconductor nanocrystal quantum dots with a CdSe / ZnS ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K11/02C09K11/70H01L33/06H01L33/28H01L33/30B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00C09K11/02C09K11/703H01L33/06H01L33/28H01L33/30
Inventor 邓正涛沈炜向爱双
Owner 南京紫同纳米科技有限公司