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Preparation method of CdTe/CdS/SiO2 composite fluorescent nanoparticle

A technology of nanoparticles and composite fluorescence, which is applied in the field of composite fluorescent nanoparticles, can solve the problems of interfering with the quantum yield of quantum dots, the decrease of quantum yield, and the destruction of crystal structure, etc., and achieve the advantages of convenient operation, small particle size, and high quantum yield. rate effect

Inactive Publication Date: 2012-01-11
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The size range of fluorescent nanoparticles obtained by this method is small (30-150nm), but the quantum yield drops a lot, only about 10%, or even lower
The decline in quantum yield is due to the change of ligands on the surface of quantum dots on the one hand, and part of the reactants enter the interior of quantum dots to destroy the crystal structure; on the other hand, the SiO 2 The shell is thick and loose, which will also interfere with the quantum yield of quantum dots

Method used

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  • Preparation method of CdTe/CdS/SiO2 composite fluorescent nanoparticle
  • Preparation method of CdTe/CdS/SiO2 composite fluorescent nanoparticle
  • Preparation method of CdTe/CdS/SiO2 composite fluorescent nanoparticle

Examples

Experimental program
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Effect test

Embodiment 1

[0028]45 mg of tellurium powder and 120 mg of sodium borohydride were added to the syringe, and then 3 mL of ultrapure water was added thereto. After reacting at low temperature for 12 hours, the black tellurium powder disappeared and white sodium borate crystals were produced. Clear NaHTe solution.

[0029] Weigh 0.4567g 2CdCl 2 ·5H 2 Dissolve O in 250mL ultrapure water, add 251μL mercaptopropionic acid (MPA), use 1M NaOH solution to adjust its pH value to 10.0, and pass N under vigorous stirring. 2 Deoxygenation was performed for 30 min, and then the newly prepared NaHTe solution was quickly added to obtain the precursor solution. The precursor solution was boiled and refluxed at 100° C. for 30 minutes to prepare the CdTe precursor. After cooling to room temperature, adjust its pH value to 10.0 after 0.5M thiourea solution, wherein thiourea and Cd 2+ The molar ratio of the CdTe / CdS core / shell quantum dots with different particle sizes is obtained by controlling the refl...

Embodiment 2

[0032] Take 500 μL of LCdTe / CdS core / shell quantum dots of Example 1, 1.8939 g of OP-5, 1.77 mL of cyclohexane, and 1.8 mL of n-hexanol in an autoclave, and quickly add 25 wt% 250 μL of ammonia water under stirring, and add after half an hour 100 μL tetraethyl orthosilicate (TEOS), replace the air with nitrogen three times, raise the system pressure to 0.8 atmospheres, and react at a low temperature of 0°C for 5 days; after the reaction, add acetone to the obtained mixed solution to precipitate the obtained fluorescence Nanoparticles, purified by low-temperature ultracentrifugation and washed with acetone ethanol to obtain CdTe / CdS / SiO with a particle size of about 20nm 2 Composite fluorescent nanoparticles with a quantum yield of 31%.

Embodiment 3

[0034] Take 500 μL of LCdTe / CdS core / shell quantum dots of Example 1, 1.8939 g of OP-5, 1.77 mL of cyclohexane, and 1.8 mL of n-hexanol in an autoclave, and quickly add 25 wt% 250 μL of ammonia water under stirring, and add after half an hour 100 μL tetraethyl orthosilicate (TEOS), replace the air with nitrogen three times, raise the system pressure to 1 atmosphere, and react at a low temperature of 0°C for 5 days; after the reaction, add acetone to the obtained mixed solution to precipitate the obtained fluorescence Nanoparticles, purified by low-temperature ultracentrifugation and washed with acetone ethanol to obtain CdTe / CdS / SiO with a particle size of about 22nm 2 Composite fluorescent nanoparticles with a quantum yield of 38%.

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Abstract

The invention relates to a CdTe / CdS / SiO2 composite fluorescent nanoparticle of high quantum yield and small particle size and its preparation method. The method comprises the steps of: first preparing a cadmium telluride (CdTe) quantum dot in a water phase with mercaptopropionic acid as the stabilizing agent, then packing the CdTe quantum dot with cadmium sulfide (CdS) in the water phase so as to form a thin protective layer and remedy the surface defect of the CdTe quantum dot and optimize the quantum dot crystal form by CdS, and then, slowing down the hydrolysis speed of tetraethyl orthosilicate at a low temperature by a low-temperature high-pressure inverse microemulsion method, and controlling the compactness of SiO2 shell, so as to obtain the CdTe / CdS / SiO2 composite fluorescent nanoparticle with small particle size and high quantum yield. By changing different oil-water ratio, surfactant type and input, as well as the technology of low-temperature high-pressure hydrolysis, etc., the particle size (20-50nm) and quantum yield (20-30%) of the obtained composite fluorescent nanoparticle can be controlled.

Description

technical field [0001] The invention relates to a method for preparing CdTe / CdS / SiO with multiple core-shell structures 2 Preparation method of composite fluorescent nanoparticles. More specifically, water-soluble CdTe / CdS core / shell quantum dots were compounded into silica nanoparticles by low temperature and high pressure reverse microemulsion method to prepare quantum dots with smaller particle size (20-50nm) and higher Composite fluorescent nanoparticles with multiple core-shell structures with quantum yield (20-30%). Background technique [0002] Quantum dots, also known as semiconductor nanocrystals (QDs), are nanoparticles composed of II-VI or III-V elements. The size of quantum dots is about 1-10nm, and its size and shape can be precisely controlled by reaction time, temperature, and ligands. When the quantum dot size is smaller than its Bohr radius, the continuous energy levels of the quantum dot begin to separate, and its value is finally determined by its size....

Claims

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Application Information

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IPC IPC(8): C09K11/88C09K11/02
Inventor 代昭宋娇娇马杏萌
Owner TIANJIN POLYTECHNIC UNIV
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