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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 bare cadmium sulfide quantum dots and their preparation, can solve the problems of loss of practical application value of semiconductor nanocrystals, undisclosed data or maps, and inability to know, so as to avoid toxicity and high cost , The fluorescence emission peak shape is good, and the crystallization is perfect.

Inactive Publication Date: 2009-06-24
SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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

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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

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Experimental program
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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. 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 2 As shown, the size of the cadmium sulfide quantum dot is about 6.6nm, the λmax is ...

Embodiment 2

[0028] 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 image 3 As shown, the size of the cadmium sulfide quantum dot is 2.0nm, the λmax is 416nm, and the h...

Embodiment 3

[0030] Measure 0.10 (mol / L) cadmium acetate 60ml and 0.10 (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 54.5mmol / L, the reaction concentration of L-cysteine ​​is 45.4mmol / L), and it is 12 to regulate pH with the concentration of 1mol / L potassium hydroxide solution. 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) photos and fluorescence emission spectra are shown in Figure 4 As shown, the size of the cadmium sulfide quantum dots is 4.998nm and 10.469nm, the latter is about twice the former, and...

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Abstract

The invention discloses a cadmium sulfide bare quantum dot, which is a granular nano crystal, and its fluorescence emission peak λmax is 415-420nm, and the half-peak width is 80-100nm. The invention also discloses its preparation by adopting a hydrothermal synthesis method by reacting a water-soluble inorganic cadmium salt with a Cd / S molar ratio of 1-1.2:1 and L-cysteine ​​in a reaction system with a pH of 9-13 method. The method of the invention is simple, easy to operate, and low in cost; CdS bare quantum dots with different particle sizes <10nm are prepared, and compared with existing products, they have high stability, good fluorescence emission peak shape, narrow half-peak width, The advantages of good monochromaticity not only win precious time for the surface modification of bare quantum dots but also improve their fluorescence performance, so that they can be used for biological tissue labeling after surface modification and other subsequent treatments.

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