Core-shell quantum dot, preparation method, device and composition thereof

Abstract

The invention discloses a core-shell quantum dot, a preparation method, a device and a composition thereof. Specifically, the core-shell quantum dot includes a quantum dot core and a shell coated on the quantum dot core, at least one layer of the shell is disposed, the outermost layer of the shell includes oxygen element and X element, wherein the X element is selected from one or more of the following elements: Mg, Ca, Sr, Ba, Ti, Zr, Cr, Mo, Mn, Fe, Co, Ni, Al, Ga and Si, and the outermost layer of the shell also includes a first element and / or a second element. The first element includes atleast one group II element except the X element, the second element includes at least one group VI element except oxygen element, and the oxygen and / or the first element are combined by a chemical bond.

Description

technical field [0001] The invention relates to the field of quantum dot materials, in particular to a core-shell quantum dot, a preparation method, a device and a composition thereof. Background technique [0002] Quantum dots, also known as semiconductor nanocrystals, have broad application prospects in the fields of display, lighting, biology, and solar cells due to their advantages such as adjustable luminous wavelength, high luminous efficiency, and good color purity, and have attracted widespread attention. In recent years, the research on II-VI group-based quantum dot materials containing CdSe and CdS has made great progress, and their efficiency, half-peak width, stability and other properties have been greatly improved, and have been applied in display, biology and other fields . However, Cd is a toxic heavy metal, and the European Union's "Regulations on the Registration, Evaluation, Authorization and Restriction of Chemicals" (referred to as "REACH") has made str...

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Problems solved by technology

[0003] In the prior art, the fluorescence quantum yield of InP-based quantum dots is low, the half-maximum width of luminescence (low color purity), and poor light, heat, and water stability are the main reasons restricting its application.

At present, the methods for improving the fluorescence quantum yield and stability of InP quantum dots mainly include: (1) etching InP quantum dots by acidic reagents, such as adding HF, NH 4 Surface treatment with weakly acidic reagents such as F can increase the efficiency from less than 1% to 20-40%, but the entire etching process is difficult to control, and the acid is easy to over-etch the InP quantum dots and destroy the surface structure of the InP quantum dots; (2) ) control nucleation and growth, improve the uniformity of quantum dots, and improve color purity; (3) build a core-shell structure of InP quantum dots by coating the ZnS shell on the outside of InP quantum dots, but because the core layer InP quantum dots The lattice parameter is 0.589nm, while the lattice parameter of the shell ZnS material is 0.542nm. The difference between the two is large, resulting in a mismatch of lattice parameters, making it difficult for the ZnS layer to completely cover the InP surface, and the resulting ZnS coating The coated InP quantum dots present an irregular polyhedral structure. In order to improve the coating efficiency of ZnS, the InP shell layer is mainly modified, and the InP core layer is etched with some inorganic acids or light to etch away the excess surface of the InP core layer. In ions, or add transition layer ZnSe to form InP / ZnSe / ZnS quantum dots; (4) Add heteroatoms to the synthetic core, such as adding Zn or Ga, etc.

Although the existing technology has played a certain role in improving the performance of InP quantum dots, there is still a lot of room for improvement.

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