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Silica-coated quantum dots and preparation method thereof

A technology of silica and quantum dots, applied in chemical instruments and methods, luminescent materials, etc., can solve the problems of quantum dot fluorescence efficiency reduction, surface defect quenching fluorescence efficiency, etc., and achieve good photostability and chemical stability, The formation method is simple and the effect of high quantum efficiency

Inactive Publication Date: 2017-12-15
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

If these organic solvents containing quantum dots are left for a period of time, the fluorescence efficiency of quantum dots will be slightly reduced. This is because a small amount of water or oxygen in the organic solvent will oxidize the quantum dots, resulting in surface defects and quenching fluorescence efficiency.

Method used

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  • Silica-coated quantum dots and preparation method thereof
  • Silica-coated quantum dots and preparation method thereof
  • Silica-coated quantum dots and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Silica-coated methylamino lead bromide (CH 3 NH 3 PbBr 3) preparation of quantum dots

[0031] Add a certain amount of methyl orthosilicate to 20mL containing CH 3 NH 3 PbBr 3 Quantum dots were analyzed in pure toluene colloidal solution. Among them, CH 3 NH 3 PbBr 3 The concentration of quantum dots is 0.64mg / mL, the added methyl orthosilicate and CH 3 NH 3 PbBr 3 The mass ratio of quantum dots is 1.7:1. The quantum dot colloid solution obtained above was introduced into a flask sealed with a rubber stopper, and stirred at 25 °C for 12 and 36 hours, respectively, to obtain silica-coated CH 3 NH 3 PbBr 3 Quantum dot nanoparticles.

[0032] Silica-coated CH obtained by stirring for 12 hours 3 NH 3 PbBr 3 The TEM morphology of quantum dots is as follows: figure 1 As shown, many CH 3 NH 3 PbBr 3 The quantum dots have been coated with silica and embedded in large silica spheres (approximately 150nm in diameter). When the stirring time is extended to 3...

Embodiment 2

[0035] Preparation of SiO2-coated Cadmium Selenide / ZnS (CdSe / ZnS) Quantum Dots

[0036] A certain amount of methyl orthosilicate was added to 50 mL of completely anhydrous toluene colloidal solution containing CdSe / ZnS quantum dots. Wherein, the concentration of CdSe / ZnS quantum dots is 300 mg / mL, and the mass ratio of added tetraethyl orthosilicate to CdSe / ZnS quantum dots is 10:1. The quantum dot colloid solution obtained above was introduced into an open flask, and stirred at 25°C for 500 hours respectively to obtain CdSe / ZnS quantum dot nanoparticles wrapped in silicon dioxide.

[0037] The pure CdSe / ZnS quantum dot colloid solution and the silica-wrapped CdSe / ZnS quantum dot sample were vacuum-filled at 50°C for 1 hour to obtain pure CdSe / ZnS quantum dot powder and silica-wrapped CdSe / ZnS quantum dots. Dot powder. Take a certain mass of these two powders to adjust to the same absorbance and place them on the Ocean Optics spectrometer (LS-450) for photostability testing....

Embodiment 3

[0039] Preparation of SiO2-coated Cadmium Selenide / Cadmium Sulfide (CdSe / CdS) Quantum Dots

[0040] Equal moles of ethyl orthosilicate and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane were added to 30 mL of analytical grade n-hexane colloidal solution containing CdSe / CdS quantum dots. Wherein, the concentration of CdSe / CdS quantum dots is 50 mg / mL, and the mass ratio of the added silylating agent to CdSe / CdS quantum dots is 4:1. The quantum dot colloid solution obtained above was introduced into a polytetrafluoroethylene hydrothermal reaction kettle, and kept at 180° C. for 2 hours to obtain CdSe / CdS quantum dot nanoparticles wrapped in silica.

[0041] Vacuumize the pure CdSe / CdS quantum dot colloid solution and the silica-wrapped CdSe / CdS quantum dot sample at 50°C for 30 minutes to obtain pure CdSe / CdS quantum dot powder and silica-wrapped CdSe / CdS quantum dots. Dot powder. Take a certain mass of these two powders and adjust them to have the same absorbance and place th...

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Abstract

The invention relates to silica-coated quantum dots and a preparation method thereof. Silica employs a silanization agent as a raw material, the raw material is added into an anhydrous organic solvent containing quantum dots, and a reaction is carried out in order to prepare silica-coated quantum dots, wherein the mass ratio of the silanization agent to the quantum dots is 0.1-10:1. During preparation, a certain amount of the silanization agent is added into the anhydrous organic solvent containing quantum dots; under a sealing or opening condition and at a certain temperature, a continuous stirring is carried out for a period of time in order to obtain a silica-coated quantum dots sample; the anhydrous organic solvent is an analytically pure organic solvent or a totally anhydrous organic solvent, and the silanization agent is used for carrying out a hydrolysis reaction depending on the organic solvent or residual moisture in air in order to obtain a silica coating. The preparation method is simple, water, ammonia, sulfydryl and other catalysts are not needed for introduction, initial fluorescence efficiency of quantum dots are not weakened, and the silica-coated quantum dots nano-material has very high quantum efficiency and stability.

Description

technical field [0001] The invention belongs to the technical field of semiconductor nanometer material (quantum dot) preparation, and in particular relates to a silicon dioxide-wrapped quantum dot prepared in an anhydrous organic solvent by using a silylating agent and a preparation method thereof. Background technique [0002] Quantum dots are semiconductor nanomaterials whose size is on the order of nanometers. After being excited by light or electricity, quantum dots can emit a spectrum of various colors. The spectrum is narrow and the quantum yield is high. It has broad application prospects in LED lighting, solar cells, biomarkers and display screens. However, the nanoscale size of quantum dots makes them have high surface activity, and they are easy to react with oxygen and water molecules in the air to form surface defects to quench the fluorescence efficiency of quantum dots. [0003] In order to improve the stability of quantum dots, it is a more effective method ...

Claims

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Application Information

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IPC IPC(8): C09K11/02C09K11/06C09K11/88C09K11/62C09K11/66C09K11/65
CPCC09K11/025C09K11/06C09K11/621C09K11/65C09K11/665C09K11/88C09K11/881C09K11/883C09K2211/188
Inventor 李良黄寿强李志春
Owner SHANGHAI JIAO TONG UNIV
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