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Cadmium sulfide bare quantum spot and preparation process

A technology of quantum dots and cadmium sulfide, applied in the field of cadmium sulfide bare quantum dots and its preparation, can solve the problems of semiconductor nanocrystals losing practical application value, unrevealed data or maps, flammable raw materials, etc., to avoid toxicity and high cost , good fluorescence emission peak shape, perfect crystallization effect

Inactive Publication Date: 2007-04-25
SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method also has unavoidable shortcomings: 1. it is impossible to prepare bare quantum dots, and the surface of quantum dots produced by metal-organic methods is often covered with an organic layer, such as TOPO (trioctylphosphine oxide, extremely poisonous and expensive). Subsequent surface modification of quantum dots has lost many options for possible optimal development; ②The metal-organic method is not only toxic, flammable, but also extremely expensive in raw materials, so it is greatly limited in practical applications
As resolvable bioluminescent quantum dots, semiconductor nanocrystals prepared by water method have lost their practical application value
In addition, it has been reported that the hydrothermal synthesis method (abbreviated as the hydrothermal method) uses water as a solvent in a closed device (autoclave), and reacts under high pressure and temperature rise conditions to prepare a 5nm size (calculated by the Scherrer formula XRD diffraction peak half peak width), spherical cubic β-CdS nanocrystals with unit cell parameter a=0.5818nm (see: ①Su Yi et al.: Hydrothermal Synthesis and Characterization of Nano ZnS and CdS, "Applied Chemistry", 1996, 13:56 ), but did not reveal the relevant data or spectra of the fluorescence emission properties of the CdS nanocrystals, and it is impossible to know whether they are CdS bare quantum dots with fluorescence emission properties

Method used

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  • Cadmium sulfide bare quantum spot and preparation process
  • Cadmium sulfide bare quantum spot and preparation process
  • Cadmium sulfide bare quantum spot and preparation process

Examples

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Embodiment 1

[0026] Measure 0.05 (mol / L) cadmium acetate 60ml and 0.05 (mol / L) L-cysteine ​​50ml according to the ratio of 1.2 and mix them in the autoclave liner (the concentration of cadmium acetate in the reaction system is 27mmol / L, the reaction concentration of L-cysteine ​​is 22.5mmol / L), and be 1mol / L potassium hydroxide solution to regulate the acidity and alkalinity of solution with concentration, make it pH be 11. The autoclave was sealed, heated and pressurized to 130° C., and magnetically stirred. The high temperature stage is kept warm for 7 hours. cooling down naturally

[0027] And after ensuring that the pressure in the autoclave drops to normal pressure, open the lid of the autoclave, transfer the material in the autoclave to a ground bottle, and store it away from light. Obtained product characterization data: atomic force microscope (AFM) photos and fluorescence emission spectra are shown in Figure 2, the size of the cadmium sulfide quantum dots is about 6.6nm, λmax i...

Embodiment 2

[0029] Measure 0.05 (mol / L) cadmium acetate 60ml and 0.05 (mol / L) L-cysteine ​​60ml according to 1 and mix them in the liner of the autoclave (the concentration of cadmium acetate in the reaction system is 25mmol) / L, the reaction concentration of L-cysteine ​​is 25mmol / L), and be 1mol / L potassium hydroxide solution with concentration to regulate the acidity and alkalinity of solution, make it pH be 12. The autoclave was sealed, heated and pressurized to 130° C., and magnetically stirred. The high temperature stage is kept warm for 7 hours. After cooling down naturally and ensuring that the pressure in the autoclave drops to normal pressure, open the lid of the autoclave, transfer the materials in the autoclave to a ground bottle, and store in the dark. Obtained product characterization data: atomic force microscope (AFM) photos and fluorescence emission spectra are shown in Figure 3, the size of the cadmium sulfide quantum dots is 2.0nm, λmax is 416nm, and the half-peak widt...

Embodiment 3

[0031] Measure 60ml of 0.10 (mol / L) cadmium acetate and 50ml of 0.10 (mol / L) L-cysteine ​​according to the ratio of Cd / S of 1.2 and mix them in the liner of the autoclave (the concentration of cadmium acetate in the reaction system is 54.5 mmol / L, the reaction concentration of L-cysteine ​​is 45.4mmol / L), and with a concentration of 1mol / L potassium hydroxide solution, the pH is adjusted to be 12. The autoclave was sealed, heated and pressurized to 130° C., and magnetically stirred. Keep warm for 6 hours in the high temperature stage. After cooling down naturally and ensuring that the pressure in the autoclave drops to normal pressure, open the lid of the autoclave, transfer the materials in the autoclave to a ground bottle, and store in the dark. Obtained product characterization data: Atomic force microscope (AFM) photo and fluorescence emission spectrum are shown in Figure 4, the size of the cadmium sulfide quantum dots is 4.998nm, 10.469nm, the latter is about twice the f...

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Abstract

The invention disclosed a kind of sulfate cadmium bare quanta spot, which is granulo- nanometer crystal. The fluorescence emission peak lambadamax and peak width at half-height are 415-420nm and 80-100nm respectively. The water-heat synthetic process is also disclosed in the invention: making the water-soluble inorganic cadmium salt (the molar ratio of the cd / s is 1-1.2:1) and the L-aminothiopropionic acid react in the pH 9-13 reaction system. The method is simple, easy to operate and is characterized by low cost. The invention has produced Cds bare quanta spot in different particle diameters (<10 nm). Compared with the present products, the product in this invention has the advantage of high stability, good fluorescence emission peak shape, and narrow peak width at half-height and good monochromaticity. It not only saves time for the surface modification, but also increases its fluorescence efficiency so that it can be used to produce tissue labels after surface modifying.

Description

technical field [0001] The invention relates to the field of nanometer materials, in particular to a cadmium sulfide (CdS) bare quantum dot and a preparation method thereof. Background technique [0002] Quantum dots (quantum dots, QDs) can also be called semiconductor nanocrystals (semiconductor nanocrystal). As a new type of fluorescent material, quantum dots do have many advantages compared with traditional organic dye molecules. One of the biggest advantages is that there are rich colors. Different types of nano-semiconductor materials can produce a family of markers with different emission wavelengths and distinct colors according to the size change, which is impossible for dye molecules. In addition, it has a wide excitation spectrum and continuous distribution, while the emission spectrum has good monochromaticity, and the color is adjustable, and it can withstand multiple excitations and light emissions, and has long-lasting stability. The surface of quantum dots i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K11/56
Inventor 汪勇先许荣辉
Owner SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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