Synthetic method for preparing CdSe/CdS/ZnS core-shell structure quantum dots by acid assistance

Abstract

The invention discloses a synthetic method for preparing CdSe / CdS / ZnS core-shell structure quantum dots by acid assistance. The synthetic method comprises the following steps: synthesizing a CdSe core quantum dot solution in a paraffin oleic acid system, using cadmium oleate as a precursor of a shell layer CdS, using a sulfur source dissolved in liquid paraffin as a precursor of the shell layers CdS and ZnS, using a zinc source dissolved in the liquid paraffin as a precursor of the shell layer ZnS, adding an organic acid in a precursor of S, and dripping the organic acid into the core quantum dot solution, wherein the organic acid reinforces the activity of the precursors of the shell layers, reduces the surface ligands of the core quantum dot, promotes the growth of the CdS shell layer on the surface of the CdSe core quantum dot and achieves epitaxial coating; dripping the precursor of Zn to wrap the ZnS shell layer to obtain a CdSe / CdS / ZnS core-shell structure quantum dot solution. The synthetic method disclosed by the invention has the advantages that the CdSe / CdS / ZnS core-shell structure quantum dots can be synthesized in the atmosphere under a non-phosphor system, the raw materials are cheap, the reaction temperature is low, the growth of the shell layers is fast, the operation is simple and mass production is suitable.

Description

technical field [0001] The invention relates to the technical field of nanomaterials for photoelectric display lighting, in particular to an acid-assisted surface passivation to prepare quantum dots with a core-shell structure and a preparation method thereof. Background technique [0002] CdSe quantum dots are a kind of semiconductor nanocrystals with excellent optical properties, and their luminescent wavelength can be adjusted with the change of their size, covering the entire visible light range. They are widely used in LEDs, solar cells, photocatalysis, bioluminescent marking, lasers and other fields. At present, due to the dangling bonds and defects on the surface of the single CdSe quantum dots, the probability of non-radiative transition is increased, which makes the luminous efficiency of CdSe quantum dots low and unstable. In order to improve the luminous efficiency and stability of CdSe quantum dots, the researchers epitaxially grown an inorganic shell layer on...

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Problems solved by technology

In the oleic acid paraffin system, the reaction temperature is low, but in order to avoid the growth of the core during the cladding process, the cladding Cd source often chooses highly active inorganic cadmium as the Cd source, so that the shell material can react at low temperature. In the epitaxial growth of the core, and to avoid the growth of the core, this method requires many types of raw materials, and the excess cadmium oleate in the core preparation process cannot be fully utilized, which increases the waste of cadmium, causes great environmental pollution, and cladding reaction time Long, the emission wavelength of quantum dots after encapsulation appears red-shifted, which is not conducive to controlling the emission wavelength of quantum dots after encapsulation

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