Nanocrystalline quantum dot with core-shell structure and preparation method of nanocrystalline quantum dot

Abstract

The invention discloses a nanocrystalline quantum dot with a core-shell structure and a preparation method of the nanocrystalline quantum dot. The method comprises the following steps: preparing a nanocrystalline core; and coating zinc sulfide in situ on the surface of the nanocrystalline core to acquire the nanocrystalline quantum dot with a core-shell structure, wherein the method further comprises a step of implementing in-situ purification on the nanocrystalline quantum dot before the step of coating zinc sulfide on the surface of the nanocrystalline core and / or further comprises a step of implementing in-situ purification on the nanocrystalline quantum dot after the step of coating zinc sulfide on the surface of the nanocrystalline core. Due to the method disclosed by the invention, the fluorescence efficiency of the nanocrystalline quantum dot with the core-shell structure and the stability of the air and the temperature are increased, and the adjustable luminescence wavelength window of the acquired nanocrystalline quantum dot is 500-700nm large. The method is easy to operate, low in cost and good in repeatability; and the acquired nanocrystalline quantum dot contains no toxic heavy metals, thereby satisfying the requirements on the applications in biological marking and biological monitoring and providing excellent luminescence materials for the aspects of illumination, solar energy and displays.

Description

technical field [0001] The invention relates to the technical field of nanomaterial preparation, in particular to a nanocrystalline quantum dot with a core-shell structure and a preparation method thereof. Background technique [0002] Semiconductor nanocrystals, or quantum dots, have attracted widespread attention because of their obvious quantum size effect and unique optical properties, and their potential applications in lighting, display, solar energy, and biomarkers. In recent years, the development and application of quantum dots have mainly focused on cadmium-containing quantum dots (such as quantum dots with CdSe as the basic emission material). As we all know, cadmium is a highly toxic heavy metal. Big damage, so its application is strictly limited. Cadmium-free quantum dots are favored because they are green and non-toxic. [0003] At present, the research on cadmium-free quantum dots mainly focuses on I-III-VI / II-VI type quantum dots, III-V / II-VI type quantum d...

AI Technical Summary

Problems solved by technology

In 2009, Peng's laboratory synthesized CuInS with core-shell structure by atomic layer continuous adsorption method. 2 The fluorescence efficiency of / ZnS quantum dots has been increased to 30%, and the stability has been partially improved, but there is still a lot of room for improvement in terms of fluorescence efficiency and stability

[0005] The problem of poor stability also exists in III-V quantum dots. For example, the efficiency of pure InP is <1%. Although the traditional ZnS coating method can improve the efficiency of InP, its stability is still poor. 90% reduction in efficiency within 24 hours

In addition, although the InP / ZnS quantum dots prepared by Reiss et al. through the one-pot method have good initial activity, their stability is seriously affected by the molar ratio of reactants, and the tunable emission wavelength window is small.

The reason may be that the traditional ZnS shell coating method cannot completely cover the core, resulting in the surface of the quantum dots being easily oxidized, resulting in poor stability.

Therefore, if the problems of low efficiency and poor stability of cadmium-free quantum dots can be solved, it will surely create a new era of cadmium-free quantum dot applications

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