Method for rapidly preparing thick-wall CdTe/CdS quantum dot with controllable shell thickness

Abstract

The invention provides a method for rapidly preparing a thick-wall CdTe / CdS quantum dot with the controllable shell thickness, belonging to the field of nanometer material synthesis. The method is characterized in that a CdTe quantum dot is used as a raw material, 3-mercaptopropionic acid is used as a stabilizing agent and a sulphur source, water is used as a solvent, cadmium salt and the 3-mercaptopropionic acid are prepared into a solution at according to certain proportions, and the CdTe / CdS core-shell type quantum dot with different CdS shell thicknesses can be obtained by controlling reaction conditions through a microwave heating reaction. The method has advantages that the reaction conditions are mild, the operation is simple and convenient, the reaction time is short, the CdS shell with the controllable thickness can grow, the light-emitting wavelength range of the prepared core-shell quantum dot is continuous and adjustable, and the core-shell quantum dot has strong light stability.

Description

[0001] technical field [0002] The invention belongs to the preparation of nanomaterials, and specifically relates to the synthesis and purification of CdTe quantum dot solutions, the preparation of cadmium source reaction precursors, and the preparation of thick-walled CdTe / CdS cores with different CdS shell thicknesses under different reaction conditions using microwave synthesis devices -Technology of shell-type quantum dots. Background technique [0003] Quantum dots are a class of semiconductor nanomaterials whose geometric scale is smaller than the Bohr exciton radius of the material, and the carrier movement is restricted in three dimensions of space, and are usually called semiconductor nanocrystals. Due to its many excellent photochemical properties, such as continuously adjustable fluorescence emission wavelength, single-wavelength excitation and multi-wavelength emission, strong photostability, and high fluorescence quantum efficiency, it has shown great promise ...

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Problems solved by technology

[0005] Although the research on thick-walled core-shell quantum dots has made great progress, the preparation of this type of quantum dots is still very difficult. The main problems are: the preparation mainly uses organic phase methods, the reaction precursors are more toxic, and the reaction temperature is high. , harsh reaction conditions and other defects, especially in order to avoid independent nucleation during the growth of the shell material, the method of surface ion layer adsorption reaction (SILAR) is adopted. It takes two steps to grow a shell layer, first adding metal precursors , then add the non-metallic precursor and keep the reaction time longer respectively, and then repeat the above process

Although there are patents related to the microwave aqueous phase preparation technology of CdTe / CdS core-shell quantum dots, such as "a microwave preparation method of water-soluble CdTe / CdS core / shell quantum dots", the patent number is 200510025505.4, The authorization announcement date is March 27, 2007, and the authorization announcement number is CN1306003C, but the CdS precursor provided by it is extremely active, which is easy to cause a large amount of CdS independent nucleation and growth, and is only applicable to thin-walled CdTe / CdS core-shell quantum dots , it is impossible to controllably prepare quantum dots with thick walls (CdS shells are more than 3 layers)

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