CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201810799122.X, filed on Jul. 19, 2018, titled “TADF POLYMER LIGAND AND QUANTUM DOT MATERIAL, METHODS OF PREPARING THE SAME, AND APPLICATIONS THEREOF”, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of quantum dot material technologies, and in particular, to a TADF polymer and a quantum dot material, methods of preparing the same, and applications thereof.

BACKGROUND

With the development of display technologies, quantum dot light-emitting diodes (QLED) have gradually become one of the mainstream development directions of display technologies in the future due to their self-luminous properties (no additional light sources are required), narrow luminous peaks, adjustable luminous colors, and high luminous efficiencies.

SUMMARY

In a first aspect, a (thermally activated delayed fluorescence) TADF polymer is provided. The TADF polymer includes a main chain, and at least one TADF reactive group and at least one quantum dot coordinating group respectively grafted onto the main chain.

In some embodiments, each of the at least one TADF reactive group includes: at least one electron-donating group; and at least one electron-withdrawing group correspondingly bonded to the at least one electron-donating group. The at least one electron-donating group includes at least one aromatic group.

In some embodiments, each of the at least one aromatic group includes at least one of a carbazolyl group, a diphenylamino group, a triphenylamino group, or a phenothiazine group. Each of the electron-withdrawing group includes at least one of a triazine group, a sulfone group, a cyano group, or a phenyl polycyano group.

In some embodiments, the main chain includes a plurality of aromatic groups. The at least one TADF reactive group and the main chain share at least one of the at least one aromatic group.

In some embodiments, each of the at least one quantum dot coordinating group includes: at least one of amino group(s), hydroxyl group(s), carboxyl group(s), mercapto group(s), thioether group(s), phosphino group(s), or phosphinyl group(s).

In some embodiments, the TADF polymer further includes at least one solubilizing group grafted onto the main chain.

In some embodiments, each of the at least one solubilizing group includes at least one of ethyl group(s), n-butyl group(s), t-butyl group(s), n-octyl group(s), tert-butylphenyl group(s), methoxy group(s), or n-butoxy group(s).

In some embodiments, a chemical structural formula of the TADF polymer is:


wherein

p is a number of TADF reactive groups grafted onto the main chain, n is a number of quantum dot coordinating groups grafted onto the main chain, and m is a number of solubilizing groups grafted onto the main chain.

In some embodiments, a chemical structural formula of the TADF polymer is:


wherein

p is a number of TADF reactive groups grafted onto the main chain, n is a number of quantum dot coordinating groups grafted onto the main chain, and m is a number of solubilizing groups grafted onto the main chain.

In some embodiments, the main chain includes a main chain formed by polymerization from at least one of an ester, an ether, an amide, or a hydrocarbon compound.

In some embodiments, the hydrocarbon compound includes at least one of an alkane, an alkene, an alkyne, or an aromatic compound. The aromatic compound includes at least one of benzene ring(s), furan(s), thiophene(s), carbazole(s), triphenylamine(s), fluorene(s), or spirofluorene(s).

In some embodiments, the main chain includes one of a homopolymer main chain, an alternating copolymer main chain, an atactic copolymer main chain, a block copolymer main chain, or a graft copolymer main chain.

In another aspect, a method of preparing a TADF polymer is provided, which is used for preparing the TADF polymer described above. The method includes: preparing a main compound for forming a main chain, a TADF compound, and a quantum dot coordinating compound respectively; mixing the main compound, the TADF compound and the quantum dot coordinating compound to perform reaction(s); and obtaining a product of the reaction as a TADF polymer.

Or, preparing a main compound for forming a main chain and a TADF compound respectively, at least one of the main compound and the TADF compound containing at least one quantum dot coordinating group; mixing the main compound and the TADF compound to perform reaction(s); and obtaining a product of the reaction as a TADF polymer;

Or, preparing a main compound for forming a main chain and a quantum dot coordinating group respectively, the main compound containing at least one TADF reactive group; mixing the main compound and the quantum dot coordinating compound to perform reaction(s); and obtaining a product of the reaction as a TADF polymer.

In some embodiments, the step of preparing a TADF compound includes: preparing an aromatic compound and an electron-withdrawing compound respectively; dissolving the aromatic compound and the electron-withdrawing compound in an organic liquid to perform reaction(s); obtaining a product of the reaction; and purifying the product of the reaction to obtain a TADF compound;

Or, the step of preparing a main compound for forming a main chain, the main compound containing at least one TADF reactive group, includes: preparing an initial compound for forming a main chain, and an electron-withdrawing compound respectively, the initial compound containing at least one aromatic group; dissolving the initial compound and the electron-withdrawing compound in an organic liquid to perform reaction(s); obtaining a product of the reaction; and purifying the product of the reaction to obtain a main compound containing at least one TADF reactive group.

In yet another aspect, a quantum dot material is provided. The quantum dot material includes: quantum dots; and the TADF polymer according to the above technical solution. The quantum dots are combined with the TADF polymer through the at least one quantum dot coordinating group in the TADF polymer.

In some embodiments, an emission spectrum of the TADF polymer at least partially overlaps with an absorption spectrum of the quantum dots; or, the emission spectrum of the TADF polymer at least partially overlaps with an excitation spectrum of the quantum dots.

In some embodiments, the quantum dots include cadmium quantum dots or cadmium-free quantum dots.

The cadmium quantum dots include: at least one of cadmium sulfide quantum dots, cadmium selenide quantum dots, cadmium telluride quantum dots, or zinc sulfide quantum dots; or, quantum dots having an alloy structure with cadmium sulfide, cadmium selenide or cadmium telluride cores; or, quantum dots having a core-shell structure with cadmium sulfide, cadmium selenide or cadmium telluride cores.

The cadmium-free quantum dots include: at least one of zinc selenide quantum dots, indium phosphide quantum dots, lead sulfide quantum dots, copper indium sulfur quantum dots, zinc oxide quantum dots, perovskite oxides quantum dots, zinc sulfide quantum dots, indium arsenide quantum dots, indium gallium arsenide quantum dots, indium gallium nitride quantum dots, gallium nitride quantum dots, zinc telluride quantum dots, silicon quantum dots, germanium quantum dots, or carbon quantum dots; or, quantum dots having an alloy structure with zinc selenide, indium phosphide, lead sulfide, copper indium sulfide, zinc oxide, perovskite oxides, indium arsenide, indium gallium arsenide, indium gallium nitride, gallium nitride, zinc telluride, silicon, germanium, or carbon cores; or, quantum dots having a core-shell structure with zinc selenide, indium phosphide, lead sulfide, copper indium sulfide, zinc oxide, perovskite oxides, indium arsenide, indium gallium arsenide, indium gallium nitride, gallium nitride, zinc telluride, silicon, germanium, or carbon cores.

In yet another aspect, a method of preparing a quantum dot material is provided, which is used for preparing the quantum dot material described above. The method includes: preparing the TADF polymer in accordance with the method of preparing a TADF polymer described above; dissolving quantum dots and the TADF polymer in an organic liquid to perform reaction(s); and obtaining a precipitate of the reaction as a quantum dot material.

In yet another aspect, a quantum dot light-emitting diode (QLED) device is provided. The QLED device includes a quantum dot light-emitting layer. A material forming the quantum dot light-emitting layer includes the quantum dot material described in the above technical solution.

In yet another aspect, a display device is provided, which includes at least one QLED device described above.

