Metal oxide coated quantum dot and preparation method thereof

Abstract

The invention relates to the technical field of quantum dot optical materials, particularly to a metal oxide coated quantum dot and a preparation method thereof. In the metal oxide coated quantum dot,the quantum dot core comprises at least three layers of metal oxides, and the refractive indexes of the metal oxide layers are gradually increased from the inner layer to the outer layer or equal. According to the invention, the quantum dots are coated with the multiple layers of the metal oxides so as to improve the oxidation resistance of the quantum dots; the refractive indexes of the metal oxide layers are gradually increased from the inner layer to the outer layer or equal, such that the good light transmittance is maintained even under the coating with the multiple layers of the metals,and the loss of exciting light entering the quantum dots can be avoided; and with the preparation method, the metal oxide coated quantum dots are synthesized by adopting the one-pot method, and are synthesized in the same reaction system without the transferring or purifying of the reaction solution so as to achieve high production efficiency, and the reaction system is always in nitrogen protection, such that the quantum dots cannot be damaged by oxygen before being coated with the metal oxide.

Description

technical field [0001] The invention relates to the technical field of quantum dot optical materials, in particular to a metal oxide-coated quantum dot and a preparation method thereof. Background technique [0002] The particle size of quantum dots is small, the specific surface area is large, and the surface energy is high. They are easily oxidized during application, which makes the fluorescence quenched. [0003] Coating metal oxides on the surface of quantum dots is a common method to improve the oxidation resistance of quantum dots. Such as the quantum dot preparation methods disclosed in patent applications CN201710199967, CN201710301382, CN201810713517, and CN201610217470.2. However, these methods have a common point: use quantum dot solution or dispersion liquid, add metal precursors for reaction to obtain a metal oxide layer. The synthesis of quantum dots and the coating of metal oxides are two separate reaction processes. Quantum dots need to be synthesized first...

AI Technical Summary

Problems solved by technology

However, the quantum structure provided by this invention has the problem of low utilization rate of excitation light; the inventor has discovered the reason for the low utilization rate of excitation light in this structure in many years of research, because the quantum dot shell in this technical solution is ZnS, ZnSe , ZnTe and ZnSeS, the refraction rate is about 2.3, 2.5, 3, 2.4 respectively; the metal oxide used is ZnO, and the refraction rate is about 1.9; The difference in refractive index is large. When the excitation light enters the medium with low refractive index from the medium with high refractive index, total reflection is easy to occur, so that the excitation light entering the quantum dot is lost at the interface between the quantum dot shell and the metal oxide.

However, there are multiple such interfaces in the structure of the invention, which significantly reduces the utilization rate of the excitation light, resulting in the loss of the luminous brightness of the product.

Images