CN115058243A

CN115058243A - Quantum dot, quantum dot cross-linked material, and quantum dot light-emitting device

Info

Publication number: CN115058243A
Application number: CN202210778858.5A
Authority: CN
Inventors: 李卓
Original assignee: BOE Technology Group Co Ltd; Beijing BOE Technology Development Co Ltd
Current assignee: BOE Technology Group Co Ltd; Beijing BOE Technology Development Co Ltd
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2022-09-16

Abstract

The disclosure provides a quantum dot, a quantum dot cross-linked substance and a quantum dot light-emitting device, and belongs to the technical field of display. The quantum dot is characterized by comprising: a quantum dot body; a first ligand having the structure X as shown in formula 1 ₁ ‑Y ₁ ‑(Z ₁ ) m1 formula 1; a second ligand having the structure X as shown in formula 2 ₂ ‑Y ₂ ‑(Z ₂ ) m2 formula 2; wherein, X ₁ 、X ₂ Is a coordination fragment and is used for forming a coordination bond with the surface of the quantum dot body; y is ₁ 、Y ₂ To join fragments, Y ₁ Connection X ₁ And the attachment Z ₁ The length of the chain between the sites of (a) is less than Y ₂ Connection X ₂ And the attachment Z ₂ The length of the strand between the sites of (a); z ₁ 、Z ₂ To be at leastA crosslinking group, m1 represents Z ₁ M2 denotes Z ₂ The number of (2); m1 and m2 are independently selected from any integer of 1-4, and m1 < m 2. The present disclosure helps to improve the stability of the crosslinked product.

Description

Quantum dot, quantum dot cross-linked material, and quantum dot light-emitting device

Technical Field

The disclosure relates to the technical field of display, in particular to a quantum dot, a quantum dot cross-linking substance and a quantum dot light-emitting device.

Background

With the deep development of the Quantum Dot preparation technology, the stability and the Light Emitting efficiency of the Quantum dots are continuously improved, the research on Quantum Dot Light Emitting Diodes (QLEDs) is continuously deep, and the application prospect of the QLEDs in the display field is gradually bright. However, the efficiency of QLEDs has not yet reached the level of mass production. One of the important reasons is that the high resolution patterning technology of QLEDs has not yet made a breakthrough.

The inorganic nano particle characteristics of the quantum dot prevent the quantum dot from forming a film by evaporation and patterning; it is difficult to achieve higher resolution by the ink jet printing method.

The above information disclosed in the background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute prior art that is known to a person of ordinary skill in the art.

Disclosure of Invention

The purpose of the disclosure is to provide a quantum dot, a quantum dot cross-linked material and a quantum dot light-emitting device, so as to improve the stability of a cross-linked product.

In order to achieve the purpose of the invention, the following technical scheme is adopted in the disclosure:

according to a first aspect of the present disclosure, there is provided a quantum dot comprising:

a quantum dot body;

a first ligand having the structure X as shown in formula 1 ₁ -Y ₁ -(Z ₁ ) m1 formula 1;

a second ligand having the structure X as shown in formula 2 ₂ -Y ₂ -(Z ₂ ) m2 formula 2;

wherein, X ₁ 、X ₂ Is a coordination fragment and is used for forming a coordination bond with the surface of the quantum dot body;

Y ₁ 、Y ₂ to join fragments, Y ₁ Connection X ₁ Site and attachment Z ₁ Has a chain length less than Y ₂ Connection X ₂ And the attachment Z ₂ The length of the strand between the sites of (a);

Z ₁ 、Z ₂ m1 represents Z for a crosslinkable group ₁ M2 denotes Z ₂ The number of (2);

m1 and m2 are independently selected from any integer of 1-4, and m1 < m 2.

According to a second aspect of the present disclosure, there is provided a quantum dot cross-linked product comprising:

a first quantum dot selected from the quantum dots of any one of claims 1-19;

a second quantum dot selected from the quantum dots of any one of claims 1-19;

the number of the first ligands and the second ligands contained in the first quantum dots and the second quantum dots is multiple;

at least part of crosslinkable groups contained by different first ligands in the first quantum dots are crosslinked, and a first layer of network structure is formed on the surface of a quantum dot body in the first quantum dots;

at least part of crosslinkable groups contained by different first ligands in the second quantum dots are crosslinked, and a second layer network structure is formed on the surface of the quantum dot body in the second quantum dots;

at least part of the crosslinkable groups contained by the second ligand in the first quantum dot are crosslinked with at least part of the crosslinkable groups contained by the second ligand in the second quantum dot, and a third-layer network structure is formed between the first quantum dot and the first quantum dot.

According to a third aspect of the present disclosure, a method for preparing a quantum dot pattern, comprises:

providing a mixed solution of a photoinitiator and the quantum dot as described in the first aspect;

coating the mixed solution on a substrate, and carrying out exposure treatment to enable crosslinkable groups in the quantum dots to be crosslinked on the surfaces of the quantum dot bodies or among the quantum dot bodies;

and carrying out development treatment to form the quantum dot pattern.

According to a fourth aspect of the present disclosure, there is provided a quantum dot light emitting layer comprising the quantum dot cross-linker as described in the second aspect.

According to a fifth aspect of the present disclosure, there is provided a quantum dot light emitting device comprising the quantum dot light emitting layer according to the fourth aspect.

The quantum dot comprises a quantum dot body, a first ligand and a second ligand, wherein Y in the first ligand ₁ Connection X ₁ And the attachment Z ₁ Is less than Y in the second ligand ₂ Connection X ₂ And the attachment Z ₂ The length of the strand between the sites of (a); and the number of crosslinkable groups in the first ligand is less than the number of crosslinkable groups in the second ligand. Therefore, when the ligands with different lengths and different numbers of crosslinkable groups can perform crosslinking reaction, a spatially graded crosslinking network can be formed to form a multilayer and compact crosslinking network so as to endure various powerful developing processes and form a stable quantum dot light-emitting layer. In addition, the cross-linked network with different chain lengths can resist small molecular components in the developing solution and enter the surface of the quantum dot body particles, so that the influence of small molecules introduced in the whole preparation process system on the quantum dots is reduced.

Drawings

The above and other features and advantages of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Fig. 1 is a schematic structural view of a first color-quantum dot ligand solution coated on a substrate in an exemplary embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a structure for forming a first color sub-pixel in an exemplary embodiment of the present disclosure;

fig. 3 is a schematic structural view of coating a second color-quantum dot ligand solution on a substrate in an exemplary embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a structure for forming a second color sub-pixel in an exemplary embodiment of the present disclosure;

fig. 5 is a schematic structural view of a third color-quantum dot ligand solution coated on a substrate in an exemplary embodiment of the present disclosure;

fig. 6 is a schematic diagram of a structure for forming a third color sub-pixel in an exemplary embodiment of the present disclosure.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure.

In the drawings, the thickness of regions and layers may be exaggerated for clarity. The same reference numerals denote the same or similar structures in the drawings, and thus detailed descriptions thereof will be omitted.

The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the embodiments of the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring major technical ideas of the disclosure.

When a structure is "on" another structure, it may mean that the structure is integrally formed with the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure via another structure.

The terms "a," "an," "the," and the like are used to denote the presence of one or more elements/components/parts; the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc. The terms "first" and "second", etc. are used merely as labels, and are not limiting on the number of their objects.

Quantum Dots (QD) are made of zinc, cadmium, selenium and sulfur atoms, are nano materials with the crystal diameter of 2-10nm, have unique photoelectric characteristics, and can emit pure monochromatic light with various colors according to the diameter of the Quantum Dots after being stimulated by photoelectricity, so that the color of light source light can be changed.

In the related art, the realization of the patterning preparation of a quantum dot film directly on a substrate (i.e., direct lithography) by using a quantum dot material with photosensitive characteristics through a mature photolithography process and a development process is an effective way for realizing high pixel density (high resolution) of a self-luminous QLED display product. However, the problems faced in the related art are: on one hand, due to incomplete development in the conventional development process, quantum dots in an unexposed region (namely, a non-target region) remain on a substrate, and then device color mixing is caused; on the other hand, when the high-efficiency development process is adopted, the quantum dots in the unexposed area are completely developed, and meanwhile, the quantum dot film in the exposed area (namely the target area) is also easily and seriously damaged by the high-efficiency development process, and even completely peeled from the surface of the substrate. Therefore, the preparation of the patterned quantum dot film by the direct photoetching method cannot be well realized.

In an embodiment of the present disclosure, there is provided a quantum dot including:

a quantum dot body;

a first ligand having structure X as shown in formula 1 ₁ -Y ₁ -(Z ₁ ) m1 formula 1;

Y ₁ 、Y ₂ to join fragments, Y ₁ Connection X ₁ Site and attachment Z ₁ The length of the chain between the sites of (a) is less than Y ₂ Connection X ₂ And the attachment Z ₂ The length of the strand between the sites of (a);

Z ₁ 、Z ₂ m1 represents Z for a crosslinkable group ₁ M2 represents Z ₂ The number of (2);

m1 and m2 are independently selected from any integer of 1-4, and m1 < m 2.

The quantum dot provided by the disclosure comprises a quantum dot body, a first ligand and a second ligand, wherein Y in the first ligand ₁ Connection X ₁ And the attachment Z ₁ Is less than Y in the second ligand ₂ Connection X ₂ And the attachment Z ₂ The length of the strand between the sites of (a); and the number of crosslinkable groups in the first ligand is less than the number of crosslinkable groups in the second ligand. Therefore, when the ligands with different lengths and different numbers of crosslinkable groups can perform crosslinking reaction, a spatially graded crosslinking network can be formed to form a multilayer and compact crosslinking network so as to resist various strong developing processes and form a stable quantum dot light-emitting layer. In addition, the cross-linked network with different chain lengths can resist small molecular components in the developing solution and enter the surface of the quantum dot body particles, so that the influence of small molecules introduced in the whole preparation process system on the quantum dots is reduced.

Quantum Dots (QDs) are inorganic semiconductor nanoparticles synthesized by solution methods and having a size between 1-10nm, which is similar to or smaller than the exciton bohr radius of the particle. The quantum dots are small in size, large in specific surface area, easy to agglomerate, and more in surface defects, so that the surfaces of the quantum dots are usually coated with organic surface ligands during application, and the organic surface ligands play a role in protection and enable the quantum dots to have good solubility in a solution. The transport of carriers (electrons and holes) in quantum dots is confined to the interior of the quantum dots, which gives the quantum dots unique optical and electrical properties. Due to the unique size-dependent properties, the absorption and emission properties of quantum dots can be easily tuned by controlling the particle size, shape or surface structure.

The disclosed quantum dot bodies can be semiconductor nanocrystals, and can have a variety of shapes such as spherical, conical, multi-armed and/or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. Here, the quantum rod may be a quantum dot body having an aspect ratio (length to width ratio) of greater than about 1, such as greater than or equal to about 2, greater than or equal to about 3, or greater than or equal to about 5. For example, the quantum rod may have an aspect ratio of less than or equal to about 50, less than or equal to about 30, or less than or equal to about 20.

The quantum dot bodies can have, for example, a particle diameter (average maximum particle length for non-spherical shapes) of, for example, about 1nm to about 100nm, about 1nm to about 80nm, about 1nm to about 50nm, or about 1nm to 20nm, or 1nm to 10 nm.

The energy band gap of the quantum dot body can be controlled according to the size and composition of the quantum dot body, and thus the light emitting wavelength can be controlled. For example, when the size of the quantum dot body is increased, the quantum dot body may have a narrow energy band gap and thus be configured to emit light in a relatively long wavelength region, and when the size of the quantum dot body is decreased, the quantum dot body may have a wide energy band gap and thus be configured to emit light in a relatively short wavelength region. For example, the quantum dot body may be configured to emit light in a predetermined wavelength region of the visible light region according to its size and/or composition. For example, the quantum dot body may be configured to emit a second color light, which may have a peak emission wavelength (λ max) in, for example, about 430nm to about 480nm, a third color light, which may have a peak emission wavelength (λ max) in, for example, about 600nm to about 650nm, or a first color light, which may have a peak emission wavelength (λ max) in, for example, about 520nm to about 560nm, but is not limited thereto.

For example, the average particle size of the quantum dot bodies configured to emit light of the second color may be, for example, less than or equal to about 4.5nm, and for example, less than or equal to about 4.3nm, less than or equal to about 4.2nm, less than or equal to about 4.1nm, or less than or equal to about 4.0 nm. Within ranges, for example, the average particle size of the quantum dot body may be about 2.0nm to about 4.5nm, such as about 2.0nm to about 4.3nm, about 2.0nm to about 4.2nm, about 2.0nm to about 4.1nm, or about 2.0nm to about 4.0 nm.

The quantum dot body can have a quantum yield of, for example, greater than or equal to about 10%, greater than or equal to about 20%, greater than or equal to about 30%, greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, or greater than or equal to about 90%.

The quantum dot body may have a relatively narrow full width at half maximum (FWHM). Here, the FWHM is a width of a wavelength corresponding to half of the peak absorption point, and when the FWHM is narrow, it may be configured to emit light in a narrow wavelength region, and a higher color purity may be obtained. The quantum dot body can have a FWHM of, for example, less than or equal to about 50nm, less than or equal to about 49nm, less than or equal to about 48nm, less than or equal to about 47nm, less than or equal to about 46nm, less than or equal to about 45nm, less than or equal to about 44nm, less than or equal to about 43nm, less than or equal to about 42nm, less than or equal to about 41nm, less than or equal to about 40nm, less than or equal to about 39nm, less than or equal to about 38nm, less than or equal to about 37nm, less than or equal to about 36nm, less than or equal to about 35nm, less than or equal to about 34nm, less than or equal to about 33nm, less than or equal to about 32nm, less than or equal to about 31nm, less than or equal to about 30nm, less than or equal to about 29nm, or less than or equal to about 28 nm. Within the ranges, it may have a FWHM of, for example, about 2nm to about 49nm, about 2nm to about 48nm, about 2nm to about 47nm, about 2nm to about 46nm, about 2nm to about 45nm, about 2nm to about 44nm, about 2nm to about 43nm, about 2nm to about 42nm, about 2nm to about 41nm, about 2nm to about 40nm, about 2nm to about 39nm, about 2nm to about 38nm, about 2nm to about 37nm, about 2nm to about 36nm, about 2nm to about 35nm, about 2nm to about 34nm, about 2nm to about 33nm, about 2nm to about 32nm, about 2nm to about 31nm, about 2nm to about 30nm, about 2nm to about 29nm, or about 2nm to about 28 nm.

For example, the quantum dot body may include a group II-VI semiconductor compound, a group III-V semiconductor compound, a group IV-VI semiconductor compound, a group IV semiconductor, a group I-III-VI semiconductor compound, a group I-II-IV-VI semiconductor compound, a group II-III-V semiconductor compound, or a combination thereof. The II-VI semiconductor compound may for example be selected from: binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or mixtures thereof; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or mixtures thereof, but not limited thereto. The III-V semiconductor compound may for example be selected from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, gainp, GaInNAs, gainsb, GaInPAs, GaInPSb, InAlNSb, inalnnas, InAlNSb, inalnpas, InAlNSb, or mixtures thereof, but are not limited thereto. The group IV-VI semiconductor compound may, for example, be selected from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto. The group IV semiconductor may, for example, be selected from: elemental (unitary) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. The I-III-VI semiconductor compound may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or a mixture thereof, but is not limited thereto. The group I-II-IV-VI semiconductor compound may be, for example, CuZnSnSe, CuZnSnS, or a mixture thereof, but is not limited thereto. The II-III-V semiconductor compound may include, for example, InZnP, but is not limited thereto.

The quantum dot body may include the elemental semiconductor, the binary semiconductor compound, the ternary semiconductor compound, or the quaternary semiconductor compound in a substantially uniform concentration or a locally different concentration profile.

For example, the quantum dot body can include a cadmium (Cd) -free quantum dot body. A cadmium-free quantum dot body is a quantum dot body that does not include cadmium (Cd). Cadmium (Cd) can cause serious environmental/health problems and is a restricted element in accordance with the hazardous substances restriction directive (RoHS) in many countries, and thus a non-cadmium-based quantum dot body can be effectively used.

As an example, the quantum dot body may be a semiconductor compound including zinc (Zn), and at least one of tellurium (Te) and selenium (Se). For example, the quantum dot body may be a Zn-Te semiconductor compound, a Zn-Se semiconductor compound, and/or a Zn-Te-Se semiconductor compound. For example, the amount of tellurium (Te) in the Zn — Te-Se semiconductor compound may be less than the amount of selenium (Se). The semiconductor compound may have a peak emission wavelength (λ max) in a wavelength region of less than or equal to about 480nm, for example, about 430nm to about 480nm, and may be configured to emit a second color light.

For example, the quantum dot body may be a semiconductor compound including indium (In) and at least one of zinc (Zn) and phosphorus (P). For example, the quantum dot body may be an In-P semiconductor compound and/or an In-Zn-P semiconductor compound. For example, In the In-Zn-P semiconductor

The molar ratio of zinc (Zn) to indium (In) In the compound can be greater than or equal to about 25. The semiconductor compound may have a peak emission wavelength (λ max) in a wavelength region of less than about 700nm, for example, about 600nm to about 650nm, and may be configured to emit a third color light.

The quantum dot body may have a core-shell structure. For example, the core and the shell of the quantum dot body may have an interface, and the element of at least one of the core or the shell in the interface may have a concentration gradient, wherein the concentration of the element of the shell decreases towards the core. For example, the material composition of the shell of the quantum dot body has a higher energy bandgap than the material composition of the core of the quantum dot body, and thus the quantum dot body may exhibit a quantum confinement effect.

The quantum dot body may have a quantum dot core and a multilayer quantum dot shell surrounding the core. Here, the multilayer shell has at least two shells, wherein each shell may be of a single composition, alloy, and/or have a concentration gradient.

For example, a shell of the multilayer shell distal from the core may have a higher energy band gap than a shell proximal to the core, and thus the quantum dot body may exhibit a quantum confinement effect.

For example, a quantum dot body having a core-shell structure may, for example, include: a core comprising a first semiconductor compound comprising zinc (Zn), and at least one of tellurium (Te) and selenium (Se); and a shell including a second semiconductor compound disposed on at least a portion of the core and having a composition different from that of the core.

For example, the first semiconductor compound may be a Zn-Te-Se based semiconductor compound including zinc (Zn), tellurium (Te), and selenium (Se), e.g., a Zn-Se based semiconductor compound including a small amount of tellurium (Te), e.g., a semiconductor compound represented by ZnTexSe1-x, where x is greater than about 0 and less than or equal to 0.05.

For example, in the Zn — Te — Se based first semiconductor compound, the molar amount of zinc (Zn) may be higher than that of selenium (Se), and the molar amount of selenium (Se) may be higher than that of tellurium (Te). For example, the molar ratio of tellurium (Te) to selenium (Se) in the first semiconductor compound may be less than or equal to about 0.05, less than or equal to about 0.049, less than or equal to about 0.048, less than or equal to about 0.047, less than or equal to about 0.045, less than or equal to about 0.044, less than or equal to about 0.043, less than or equal to about 0.042, less than or equal to about 0.041, less than or equal to about 0.04, less than or equal to about 0.039, less than or equal to about 0.035, less than or equal to about 0.03, less than or equal to about 0.029, less than or equal to about 0.025, less than or equal to about 0.024, less than or equal to about 0.023, less than or equal to about 0.022, less than or equal to about 0.021, less than or equal to about 0.02, less than or equal to about 0.019, less than or equal to about 0.017, less than or equal to about 0.016, less than or equal to about 0.014, less than or equal to about 0.011, less than or equal to about 0.013, less than or equal to about 0.012, less than or equal to about 0.013, less than or equal to about 0.012, less than or equal to about 0., Or less than or equal to about 0.01. For example, the molar ratio of tellurium (Te) to zinc (Zn) in the first semiconductor compound can be less than or equal to about 0.02, less than or equal to about 0.019, less than or equal to about 0.018, less than or equal to about 0.017, less than or equal to about 0.016, less than or equal to about 0.015, less than or equal to about 0.014, less than or equal to about 0.013, less than or equal to about 0.012, less than or equal to about 0.011, or less than or equal to about 0.010.

The second semiconductor compound can include, for example, a group II-VI semiconductor compound, a group III-V semiconductor compound, a group IV-VI semiconductor compound, a group IV semiconductor, a group I-III-VI semiconductor compound, a group I-II-IV-VI semiconductor compound, a group II-III-V semiconductor compound, or a combination thereof. Examples of the II-VI semiconductor compound, the III-V semiconductor compound, the IV-VI semiconductor compound, the IV semiconductor, the I-III-VI semiconductor compound, the I-II-IV-VI semiconductor compound, and the II-III-V semiconductor compound are the same as those described above.

For example, the second semiconductor compound may include zinc (Zn), selenium (Se), and/or sulfur (S). For example, the shell can include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed adjacent to the core and an outermost shell disposed at an outermost side of the quantum dot body. The inner shell can include ZnSeS, ZnSe, or a combination thereof, and the outermost shell can include ZnS. For example, the shell may have a concentration gradient of one component, and the amount of, for example, sulfur (S) may increase as one leaves the core.

For example, a quantum dot body having a core-shell structure may include: a core including a third semiconductor compound including indium (In), and at least one of zinc (Zn) and phosphorus (P); and a shell disposed on at least a portion of the core and including a fourth semiconductor compound having a different composition from the core.

In the In-Zn-P based third semiconductor compound, a molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. For example, the molar ratio of zinc (Zn) to indium (In) In the In-Zn-P based third semiconductor compound may be greater than or equal to about 28, greater than or equal to about 29, or greater than or equal to about 30. For example, the molar ratio of zinc (Zn) to indium (In) In the In-Zn-P based third semiconductor compound may be less than or equal to about 55, such as less than or equal to about 50, less than or equal to about 45, less than or equal to about 40, less than or equal to about 35, less than or equal to about 34, less than or equal to about 33, or less than or equal to about 32.

The fourth semiconductor compound can include, for example, a group II-VI semiconductor compound, a group III-V semiconductor compound, a group IV-VI semiconductor compound, a group IV semiconductor, a group I-III-VI semiconductor compound, a group I-II-IV-VI semiconductor compound, a group II-III-V semiconductor compound, or a combination thereof. Examples of the II-VI semiconductor compound, the III-V semiconductor compound, the IV-VI semiconductor compound, the IV semiconductor, the I-III-VI semiconductor compound, the I-II-IV-VI semiconductor compound, and the II-III-V semiconductor compound are the same as described above.

For example, the fourth semiconductor compound may include zinc (Zn) and sulfur (S), and optionally selenium (Se). For example, the shell can include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed adjacent to the core and an outermost shell disposed at an outermost side of the quantum dot body. At least one of the inner shell and the outermost shell may include a fourth semiconductor compound ZnS, ZnSe, or ZnSeS.

In the present disclosure, for brevity and clarity, the quantum dot body schematic diagrams referred to throughout are all represented by circles, and the actually used quantum dot body materials are not limited to spherical quantum dots, and include but not limited to quantum dot materials of any geometric shapes such as sphere, ellipsoid, polyhedron, rod, cross, ring and the like.

The chain length between the site of the connecting fragment connected with the coordination fragment and the site of the connecting fragment connected with the crosslinkable group in the disclosure refers to the length of the main chain between the two sites, and the larger the number of atoms contained in the main chain between the two sites is, the longer the length is. That is, the number of atoms of the backbone between the site of the linking moiety in the first ligand to which the coordinating moiety is attached and the site of the linking moiety to which the cross-linkable group is attached is less than the number of atoms of the backbone between the site of the linking moiety in the second ligand to which the linking moiety is attached and the site of the linking moiety to which the cross-linkable group is attached. In some embodiments, the number of atoms in the backbone between the site of the linking moiety to the coordinating moiety and the site of the crosslinkable group in the first ligand is from 2 to 30; the number of atoms of a main chain between a site of the connecting fragment connected with the coordination fragment and a site of the connecting crosslinkable group in the second ligand is 8-45;

in some embodiments of the present disclosure, the quantum dot further comprises:

a third ligand having the structure X as shown in formula 3 ₃ -Y ₃ -(Z ₃ ) m3 formula 3;

wherein, X ₃ Is a coordination fragment and is used for forming a coordination bond with the surface of the quantum dot body;

Y ₃ to join fragments, Y ₂ Connection X ₂ And the attachment Z ₂ Has a chain length less than Y ₃ Connection X ₃ And the attachment Z ₃ The length of the strand between the sites of (a);

Z ₃ m3 represents Z for a crosslinkable group ₃ The number of (2);

m3 is selected from any integer of 1-4, and m2 < m 3.

In this embodiment, the number of atoms of the backbone between the site of the linking moiety to the coordinating moiety and the site of the linking moiety to the crosslinkable group in the first ligand is less than the number of atoms of the backbone between the site of the linking moiety to the coordinating moiety and the site of the linking moiety to the crosslinkable group in the second ligand is less than the number of atoms of the backbone between the site of the linking moiety to the coordinating moiety and the site of the linking moiety to the crosslinkable group in the third ligand. The number of atoms of the main chain between the site of the connecting fragment connected with the coordination fragment and the site connected with the crosslinkable group in the third ligand is 8-45. Preferably, the number of atoms of the backbone between the site of the linking moiety to the coordinating moiety and the site of the cross-linkable group in the first ligand is from 2 to 15; the number of atoms of the main chain between the site of the connecting fragment connected with the coordination fragment and the site of the connecting fragment connected with the crosslinkable group in the second ligand is 8-30, and the number of atoms of the main chain between the site of the connecting fragment connected with the coordination fragment and the site of the connecting fragment connected with the crosslinkable group in the third ligand is 14-45.

The quantum dots provided by the present disclosure include ligands of different lengths and different numbers of crosslinkable groups, wherein the length of the first ligand < the length of the second ligand < the length of the third ligand, and the number of crosslinkable groups in the first ligand < the number of crosslinkable groups in the second ligand < the number of crosslinkable groups in the third ligand. Thus, the present disclosure matches "short, medium, long" ligand molecules of different lengths to "few, medium, many" of cross-linking sites, respectively, which may have the following beneficial effects:

firstly, the short-chain ligand molecules mainly perform the cross-linking of the ligand molecules with the same length on the quantum dot body, namely the short-chain ligand molecules are mainly cross-linked with other short-chain ligand molecules coordinated on the same quantum dot body (the probability that the short-chain ligand molecules contact the ligand molecules on other quantum dot bodies is very small), so that a cross-linked network which takes the quantum dot body as the center and wraps the quantum dot body is formed in space, cross-linked points of the cross-linked network at the level are the most dense, and the influence and damage of micromolecules or other solvents and the like in a developing solution on the quantum dots can be avoided.

Furthermore, the molecules of the "middle" or/and "long" chains in the ligand molecule mainly cause cross-linking between different quantum dot bodies, that is, mainly play a role in cross-linking adjacent quantum dot bodies together (because the longer-chain ligand molecule can contact with the ligand molecule on the adjacent quantum dot body more probably); the cross-linked network of the level mainly plays a role in firmly connecting adjacent quantum dot bodies with each other to form a compact quantum dot film, and can resist the 'damage' of various developing processes.

In addition, the disclosure will "short, medium, long" ligand molecules of different lengths to "few, medium, many" of cross-linking sites, respectively, based on steric hindrance considerations. When the ligand molecule has insufficient length, there is insufficient space for accommodating a plurality of crosslinkable groups, and if a plurality of crosslinkable groups are forcibly connected to a shorter ligand molecule, the number or density of the ligand molecules on the surface of the quantum dot body is sacrificed, which results in poor passivation of the surface of the quantum dot body on one hand and a relatively loose crosslinked network formed on the other hand.

In a whole, the short, medium and long molecular length and the cross-linking sites of the quantum dot matrix are little, medium and large in adaptation, the number of the ligand molecules on the surface of the quantum dot matrix can be guaranteed to the greatest extent, meanwhile, a proper space is provided for the cross-linkable groups, and finally, a layer-by-layer compact spatial grading cross-linking network is formed in the spatial distance of 'near, medium and far' by taking the quantum dot matrix as the center.

It is to be noted that the first ligand may be a short-chain ligand or a medium-chain ligand, and the second ligand and the third ligand may be a medium-chain ligand or a long-chain ligand. The number of crosslinkable groups in the first ligand may be one or two, and the number of crosslinkable groups in the second ligand and the third ligand may be two or three. For example, the number of crosslinkable groups in the first ligand is one, the number of crosslinkable groups in the second ligand is two, and the number of crosslinkable groups in the third ligand is three.

In the present disclosure, m1, m2, m3 may each independently be selected from 1, 2 or 3.

In some embodiments of the present disclosure, the coordinating fragment is selected from the group consisting of structures represented by formula X-1 or formula X-2:

wherein, the first and the second end of the pipe are connected with each other,

represents a chemical bond;

A ₁ 、A ₂ a capping group that is a structure or chain termination remaining when the polymerization reaction is initiated to form a polymer;

M ₁ 、M ₂ 、M ₃ 、M ₄ and M ₅ Each independently selected from hydrogen and a structure represented by formula M-1, and M ₁ And M ₂ One and only one of them is selected from the structures shown by the formula M-1, and M ₃ And M ₄ Wherein only one is selected from the structures represented by the formula M-1;

rqx is selected from coordination group for forming coordination bond with quantum dot bulk;

rcx is selected from arylene with 6-12 carbon atoms, alkylene with 1-8 carbon atoms and a structure shown in a formula R-1;

R ₀ selected from alkylene with 1-8 carbon atoms and a structure shown as a formula R-1;

R ₁ 、R ₂ each independently selected from hydrogen, alkylene of 1-8 carbon atoms, and R ₁ 、R ₂ At least one of them is selected from alkylene groups having 1 to 8 carbon atoms, L ₁ Selected from amide bonds, ester bonds, nitrogen-containing heterocycles;

dx is selected from a ring-closing reactive group for reacting

A ring closure reaction is carried out to form a structure shown as a formula X-2;

n1 is selected from any integer of 0-80, n2 is selected from any integer of 0-80, and 2 is not less than n1+ n2 is not less than 80;

n3 is selected from any integer of 0-150, n4 is selected from any integer of 0-150, 20 is less than or equal to n3+ n4 is less than or equal to 150;

when n1 is not less than 2 and n3 is not less than 2, M in each repeating unit ₁ 、M ₂ Each independently the same or different; when n2 is not less than 2 and n4 is not less than 2, M in each repeating unit ₃ 、M ₄ Each independently the same or different.

In the present disclosure, the description "independently selected from" is used in a broad sense, which means that the specific options expressed between the same symbols in different groups do not affect each other, or that the specific options expressed between the same symbols in the same groups do not affect each other.

In the present disclosure, the end capping group may be methyl, ethyl, methoxy, vinyl, etc.; the structure remaining when initiating polymerization to form a polymer may be:

the initiator for initiating the polymerization reaction may be AIBN (azobisisobutyronitrile) initiator and BPO (dibenzoyl peroxide) initiator.

In the present disclosure, "alkyl" may include straight chain alkyl or branched alkyl. Alkyl groups may have 1 to 8 carbon atoms, and in the present disclosure, numerical ranges such as "1 to 10" refer to each integer in the given range; for example, "1 to 10 carbon atoms" means that 1 carbon atom, 2 carbon atoms, 3 carbon atoms, 4 carbon atoms, 5 carbon atoms, 6 carbon atoms, 7 carbon atoms, 8 carbon atoms can be included.

Alternatively, the alkyl group is selected from alkyl groups having 1 to 6 carbon atoms, and specific examples include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, neohexyl.

In the present disclosure, reference to alkylene refers to a divalent group formed by an alkyl group further lacking one hydrogen atom.

In the present disclosure, aryl refers to an optional functional group or substituent derived from an aromatic carbon ring. The aryl group can be a monocyclic aryl group (e.g., phenyl) or a polycyclic aryl group, in other words, the aryl group can be a monocyclic aryl group, a fused ring aryl group, two or more monocyclic aryl groups joined by carbon-carbon bonds in a conjugated manner, a monocyclic aryl group and a fused ring aryl group joined by carbon-carbon bonds in a conjugated manner, or two or more fused ring aryl groups joined by carbon-carbon bonds in a conjugated manner. That is, unless otherwise specified, two or more aromatic groups conjugated through a carbon-carbon bond may also be considered aryl groups of the present disclosure. The fused ring aryl group may include, for example, a bicyclic fused aryl group (e.g., naphthyl group), a tricyclic fused aryl group (e.g., phenanthryl group, fluorenyl group, anthracyl group), and the like. The aryl group does not contain a hetero atom such as B, N, O, S, P, Se or Si. For example, biphenyl, terphenyl, and the like are aryl groups in the present disclosure. The number of carbon atoms of the aryl group may be 6 to 12, and examples of the aryl group may include, but are not limited to, phenyl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl, biphenyl, terphenyl, quaterphenyl,Penta-biphenyl, benzo [9,10 ]]Phenanthryl, pyrenyl, benzofluoranthenyl, phenanthrenyl, pyrenyl,

and the like.

In the present disclosure, the term "arylene" refers to a divalent group formed by an aryl group further lacking a hydrogen atom.

In the present disclosure, a coordinating group is a group capable of coordination bonding with the bulk of a quantum dot. Rqx may be, for example, carboxyl (-COOH), amino (-NH), amino (-COOH) ₂ RNH-, mercapto (-SH)), ester (-COOR), hydroxyl (-OH), phosphorus/phosphine (- (R) ₂ P-), phosphoxy ((R) ₂ One or more of PO-), hydroxyl phosphorus oxy (-PO (OH)2) and other functional groups; wherein R may be an alkyl group of 1 to 10.

In the disclosure, n1 is selected from any integer of 0-80, n2 is selected from any integer of 0-80, 2 ≤ n1+ n2 ≤ 80; preferably, 4. ltoreq. n1+ n 2. ltoreq.30.

n3 is selected from any integer of 0-150, n4 is selected from any integer of 0-150, and 20 is less than or equal to n3+ n4 is less than or equal to 150. Preferably 20 ≦ n3+ n4 ≦ 60.

In the present disclosure, M in each repeating unit ₁ 、M ₂ Each independently the same or different, means M in each repeating unit ₁ M in each repeating unit, which may be the same or different ₂ May be the same or different.

For example, when n1 ≧ 2, each cell

M in (1) ₁ May be the same or different, each element

M in (1) ₂ May be the same or different.

Similarly, in the present disclosure, in each repeating unitM of (A) ₃ 、M ₄ Each independently the same or different, means M in each repeating unit ₃ M in each repeating unit, which may be the same or different ₄ May be the same or different.

For example, when n2 ≧ 2, each cell

M in (1) ₃ Can be the same or different, each unit

M in (1) ₄ May be the same or different.

According to the method, in order to enable the ligand molecules to be bonded with the surface of the quantum dot body more stably, namely, the ligand molecules can be firmly combined with the quantum dot body, a plurality of coordination groups capable of being coordinated with the quantum dot body are introduced into a single ligand molecule, and meanwhile, the topological structure (namely, coordination fragments) of a molecular chain is changed, so that the ligand molecules are not easy to separate from the surface of the quantum dot body.

In some embodiments of the disclosure, Rcx is selected from alkylene groups having 1-6 carbon atoms or the group consisting of the following structures:

wherein R is ₁ 、R ₂ Each independently selected from hydrogen, alkylene of 1-6 carbon atoms, and R ₁ 、R ₂ At least one of them is selected from alkylene groups having 1 to 6 carbon atoms.

In the present disclosure, the number of carbon atoms of the alkylene group having 1 to 6 carbon atoms may be 1, 2, 3,4, 5, 6; it may be methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, neopentylene, n-pentylene, isopentylene, neopentylene, n-hexylene, isohexylene, neohexylene, but is not limited thereto.

In some embodiments of the disclosure, R ₀ Selected from alkylene groups having 1 to 6 carbon atoms or groups consisting of the following structures：

In the present disclosure, Dx represents a functional group formed after a ring closure reaction, and plays a role in connecting two ends of a molecular main chain to form a ring structure.

In general, Dx has a chemical structure formed by chemical bonds formed between functional groups with high reaction efficiency and high reaction rate, such as a common click reaction or quasi-click reaction, for example, "azide-alkyne", "mercapto-alkene", "succinimidyl ester-amino", and the like.

In some embodiments of the disclosure, Dx is selected from the group consisting of the structures:

wherein n5 is selected from any integer from 1 to 18;

R ₀ ' selected from alkylene groups having 1 to 8 carbon atoms,

R ₁ ’、R ₂ ' each is independently selected from hydrogen, alkylene having 1 to 8 carbon atoms, and R ₁ ’、R ₂ ' at least one of them is selected from alkylene groups having 1 to 8 carbon atoms, L ₁ ' is selected from amide bond, ester bond, and nitrogen-containing heterocycle.

Wherein n5 is selected from any integer of 1-18, specifically, n5 can be 1, 2, 3,4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14 or 15.

R ₀ ' may be selected from alkylene groups having 1 to 6 carbon atoms or from the group consisting of the following structures:

wherein R is ₁ ’、R ₂ ' each is independently selected from hydrogen, alkylene having 1 to 6 carbon atoms, and R ₁ ’、R ₂ At least one of them is selected from alkylene groups having 1 to 6 carbon atoms.

In the disclosure, for the structure represented by Dx D-1, before the ring closure reaction occurs, two ends of a molecular chain respectively contain an alkynyl group and an azide group, and the ring closure reaction occurs under a click reaction catalyst and corresponding reaction conditions, so that the structure represented by D-1 can be formed. The nitrogenous five-membered ring at the right end in the structural formula is a structure obtained after the reaction of the alkynyl group and the azide group (ring closing reaction).

For the structure shown by Dx D-2, a molecular chain with two ends of sulfydryl (-SH) is added into a reaction system, and the molecular chain is closed into a ring molecule by utilizing click reaction between the sulfydryl and a carbon-carbon double bond of olefin. The molecule of Dx of this type has a structure obtained by addition reaction of mercapto groups at both ends of a molecular chain with an alkylene group (carbon-carbon double bond) at the end of the original target molecular chain.

In the structure shown by Dx D-3, before the ring-closing reaction occurs, two ends of the molecular chain respectively comprise a succinimide ester group and an amino group. After amino group is subjected to deprotection and the reaction system is adjusted to be alkalescent, the succinimide ester at the tail end of the molecular chain and the amino group rapidly undergo high-efficiency quasi-click reaction (amino group opens active ester) to form an amido bond, and as shown in D-3, the molecular chain is closed.

In the present disclosure, after the ring closure reaction, the coordination fragment is selected from the group consisting of the following structures:

it should be noted that the coordination fragments of the first ligand, the second ligand and the third ligand may be the same or different, and the length of the coordination fragments contained in the three ligands may be the same or different.

In some embodiments of the disclosure, the linker fragment is selected from the group consisting of

Wherein the content of the first and second substances,

represents a chemical bond;

a structure represented by formula Y-1 for linking to said coordinating fragment, and a structure represented by formula Q-1 for linking to said cross-linking fragment;

L ₀ selected from alkane chains with 2-20 carbon atoms and polyether molecular chains with 2-15 polymerization degrees;

L ₂ selected from the group consisting of a single bond and-O-;

h is selected from C, Si or an alkane chain having multiple attachment sites;

Q ₁ 、Q ₂ 、Q ₃ each independently selected from hydrogen, alkyl with 1-6 carbon atoms or a structure shown in a formula Q-1, and Q ₁ 、Q ₂ 、Q ₃ At least one of them is selected from the structures shown in the formula Q-1;

L ₃ selected from polyethylene glycol chain or polyethylene oxide chain with polymerization degree of 1-8, C1-10 alkane chain, -O-and-O-Si (R) ₉ R ₁₀ )—，R ₉ 、R ₁₀ Each independently selected from hydrogen or methyl;

rac and Rbc are independently selected from arylene with 6-12 carbon atoms, alkylene with 1-8 carbon atoms and a structure shown in a formula R-2; rbc for attachment of a crosslinkable group;

R ₃ 、R ₄ each independently selected from hydrogen, alkylene of 1-8 carbon atoms, and R ₃ 、R ₄ At least one of them being selected from carbon atomsAlkylene of a number 1 to 8, L ₄ Selected from amide bond, ester bond, and nitrogen-containing heterocycle.

In the present disclosure, "an alkane chain" may include a straight-chain alkyl group, an alkylene group or a branched-chain alkyl group, an alkylene group, etc., and may also include a straight-chain alkane chain and a branched-chain alkane chain having a plurality of attachment sites. The number of carbon atoms of the alkane chain may be any number from 1 to 20, such as 1, 2, 3,4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

In the present disclosure, the degree of polymerization refers to the number of repeating units in the polymer.

In the present disclosure, the length of the first ligand, the second ligand and the third ligand is determined mainly by the length of the connecting segment, and specifically can be determined by L in the connecting segment ₀ Is determined by the chain length of (a).

In some embodiments of the disclosure, Rac, Rbc are each independently selected from the group consisting of alkylene groups having 1-6 carbon atoms or the following structures:

wherein R is ₃ 、R ₄ Each independently selected from alkylene groups having 1 to 6 carbon atoms.

In some embodiments of the disclosure, H is selected from C, Si or the following structure:

wherein, # denotes the above structure for use with

Connected, # # denotes the above structure for use with Q ₁ 、Q ₂ 、Q ₃ And (4) connecting.

In some embodiments of the disclosure, L ₃ Selected from the group consisting of the following structures:

wherein x1 is selected from any integer from 1 to 8;

x2 and x3 represent the degree of polymerization, and x2 and x3 are each independently selected from any integer from 1 to 6.

Specifically, x2 and x3 are each independently selected from 1, 2, 3,4, 5, 6.

Further, L ₀ Selected from the group consisting of the following structures:

wherein R is ₅ 、R ₆ 、R ₇ Each independently selected from hydrogen, methyl, ethyl;

x4 is selected from any integer from 2 to 20;

x5 and x6 represent the degree of polymerization, and x5 and x6 are each independently selected from any integer from 2 to 15.

Specifically, x4 is selected from 2, 3,4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. x5 and x6 are each independently selected from the group consisting of, 3,4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15.

In some embodiments of the disclosure, L ₀ Selected from the structures shown in the formula L-1, wherein x4 in the first ligand is selected from any integer from 2 to 14, and x4 in the second ligand is selected from any integer from 8 to 20; or

L ₀ Selected from the structures shown in the formula L-2, wherein x5 in the first ligand is selected from any integer from 2 to 10, and x5 in the second ligand is selected from any integer from 5 to 15; or

L ₀ Is selected from a structure shown as a formula L-3, x6 in the first ligand is selected from any integer from 2 to 10, and x6 in the second ligand is selected from any integer from 5 to 15.

In some embodiments of the present disclosure, when the quantum dot further comprises the third ligand;

L ₀ selected from the structure shown in the formula L-1, x4 in the first ligand is selected from any integer of 2-8, and x in the second ligand4 is selected from any integer from 8 to 14, and x4 in the third ligand is selected from any integer from 14 to 20; or

L ₀ Selected from the structures shown in the formula L-2, x5 in the first ligand is selected from any integer from 2 to 5, x5 in the second ligand is selected from any integer from 5 to 10, and x5 in the third ligand is selected from any integer from 10 to 15; or

L ₀ Selected from the structure shown in the formula L-3, x6 in the first ligand is selected from any integer from 2 to 5, x6 in the second ligand is selected from any integer from 5 to 10, and x6 in the third ligand is selected from any integer from 10 to 15.

In some embodiments of the disclosure, L contained in the linking segment of the first ligand ₀ Is shorter than L contained in the linking fragment of the second ligand ₀ The chain length of (a);

when the quantum dot further comprises a third ligand, L contained in the linker segment in the second ligand ₀ Is shorter than L contained in the linking segment in the third ligand ₀ The chain length of (a).

Specifically, the connecting fragment is selected from the group consisting of the following structures:

wherein, L in the formula Y-1-5 ₀ Chain length of the formula (Y-1-1) or L in the formula (Y-1-2) ₀ Chain length of the formula (Y-1-3) or L in the formula (Y-1-4) ₀ The chain length of (a);

l in the formula Y-1-8 ₀ Chain length of < L in the formula Y-1-7 ₀ Chain length of < L in the formula Y-1-6 ₀ The chain length of (a);

l in the formula Y-1-10 and the formula Y-1-11 ₀ Chain length of < L in the formula Y-1-9 ₀ The chain length of (a);

the values of x2 and x3 in the structures can be the same or different, and x2 and x3 are respectively selected from any integer from 1 to 6.

In the disclosure, the first ligand can be selected from structures shown in formula Y-1-5, formula Y-1-1, formula Y-1-2, formula Y-1-8, formula Y-1-7, formula Y-1-10, and formula Y-1-11;

the second ligand and the third ligand can be selected from other structures except the formula Y-1-5, the formula Y-1-8, the formula Y-1-10 and the formula Y-1-11, as long as the length of the first ligand is less than that of the second ligand and less than that of the third ligand, and the number of the crosslinkable groups of the first ligand is less than that of the second ligand and less than that of the third ligand.

In some embodiments of the present disclosure, the crosslinkable group is selected from the group consisting of structures represented by formula Z-1 or formula Z-2:

wherein ring A is selected from an unsaturated five-membered ring or six-membered ring containing at least one carbon-carbon double bond;

R ₈ selected from hydrogen, oxygen, hydroxyl, sulfydryl, amino, carboxyl, alkane chain with 1-16 carbon atoms, alkene chain with 2-10 carbon atoms and arene structure with 6-20 carbon atoms;

when R is ₈ When attached to a carbon atom of a carbon-carbon double bond in ring A, R ₈ Selected from the group consisting of oxygen, an alkane chain having 1 to 16 carbon atoms, an alkene chain having 2 to 10 carbon atoms, and an arene structure having 6 to 20 carbon atoms;

R ₁₁ selected from C1-16 alkane chain, C2-10 alkene chain, and C6-20 aromatic hydrocarbon structure;

n8 represents R ₈ The number of (2);

when ring a is a five-membered ring, n8 is a positive integer of not more than 4;

when ring A is a six-membered ring, n8 is selected from a positive integer not exceeding 5.

In some embodiments of the disclosure, ring a is selected from the group consisting of the following structures:

in some embodiments of the present disclosure, the crosslinkable group is selected from the group consisting of the following structures:

wherein R is ₈ Selected from hydrogen, hydroxyl, sulfydryl, amino, carboxyl, alkane chain with 1-16 carbon atoms, alkene chain with 2-10 carbon atoms and arene structure with 6-20 carbon atoms;

when R is ₈ When connected to a carbon atom of a carbon-carbon double bond in each of the above structures, R ₈ Selected from C1-16 alkane chain, C2-10 alkene chain, and C6-20 aromatic hydrocarbon structure;

R ₁₁ is selected from C1-16 alkane chain, C2-10 alkene chain, and C6-20 arene structure.

R in the above formulae ₈ May be the same or different.

In the present disclosure, the ring-structure crosslinkable group has higher crosslinking stability than the common non-ring-forming crosslinkable group.

For example, the crosslinkable groups of the present disclosure are capable of undergoing the following crosslinking reaction. Here, it should be noted that R in the following three crosslinking systems ₁ To R ₅ 、Rx、R ₁ ’、R ₂ ’、R ₁ ”、R ₂ "is used only to distinguish substituents at different substitution sites in the crosslinkable group. The specific selection groups can be referred to R in the above examples ₈ 。

The dotted circle in the cross-linking type is a carbon atom site forming a chemical bond, namely the cross-linking site with a ring-shaped structure formed by at least four carbon atoms after chemical cross-linking is formed between two ligand molecules, and can be visually seen as a mode that four hands are mutually connected.

In the general photosensitive crosslinking mode, the single crosslinking sites formed are reacted as follows:

the photosensitive cross-linking agent is used for initiating the carbon-hydrogen bond cross-linking of the alkane chain, and the following cross-linking reaction (taking the azido as an example) mainly occurs:

by comparing the cyclic crosslinkable group of the present disclosure with a general photosensitive crosslinkable group, it can be found that the crosslinkable group of the present disclosure has more carbon atoms connected to each other in the case of the same number of crosslinkable groups, the crosslinking site is increased by 2 times compared to a general crosslinkable group, and is a cyclic crosslinking site. The formation of the annular cross-linking sites can form more stable and firm cross-linking sites on one hand, so that the cross-linked network is more stable, and on the other hand, the annular cross-linking sites of the present disclosure can make the formed cross-linked network more dense. Because the cross-linking sites are nodes of the whole cross-linking network, the annular cross-linking sites are formed by connecting four or six atoms which are connected in pairs, and each node of the general cross-linking structure is mainly one atom, the nodes formed by the annular cross-linking sites are larger in space, and the cross-linking network can be more densely concentrated.

The present disclosure also provides a quantum dot cross-linked material, comprising:

a first quantum dot selected from the quantum dots of any of the embodiments described above;

a second quantum dot selected from the quantum dots of any of the embodiments described above;

wherein the number of the first ligand and the second ligand contained in each of the first quantum dot and the second quantum dot is multiple;

When the first quantum dot and the second quantum dot further include a third ligand,

at least part of the crosslinkable groups contained in the third ligand in the first quantum dot are crosslinked with at least part of the crosslinkable groups contained in the third ligand in the second quantum dot, and a fourth-layer network structure is formed between the first quantum dot and the first quantum dot.

In the disclosure, a first layer network structure and a second layer network structure are formed on the surface of the quantum dot body, and a third layer network structure and a fourth layer network structure are formed between the quantum dot bodies, and the whole forms a multilayer cross-linked network separated in space.

The present disclosure also provides a method for preparing a quantum dot pattern, comprising:

providing a mixed solution of a photoinitiator and quantum dots as described in any of the above embodiments;

and carrying out development treatment to form the quantum dot pattern.

The present disclosure also provides a quantum dot light emitting layer including the quantum dot cross-linker as in the above embodiments.

The present disclosure also provides a quantum dot light emitting device including the above quantum dot light emitting layer.

The quantum dot light emitting device provided by the present disclosure may be an electroluminescent quantum dot light emitting device or a photoluminescent quantum dot light emitting device.

In some embodiments of the present disclosure, the quantum dot light emitting device further comprises an anode, a cathode, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. In one embodiment of the present disclosure, the quantum dot light emitting device may include a substrate, and a first electrode, a hole injection layer, a hole transport layer, a quantum dot light emitting layer, an electron transport layer, an electron injection layer, and a second electrode sequentially stacked and disposed on one side of the substrate.

In some embodiments of the present disclosure, the quantum dot light emitting device may also be a photoluminescent quantum dot device including a light emitting unit, the quantum dot light emitting layer being disposed at one side of the light emitting unit. The quantum dot light emitting device may include a first substrate and a second substrate. The first substrate and the second substrate may be disposed opposite to each other, for example, the first substrate may be a substrate on which components such as a light source are disposed, and the second substrate may be a substrate on which components such as a color film are disposed.

The present disclosure also provides a method for manufacturing a quantum dot light emitting device, including:

providing a first color mixed solution, wherein the first color mixed solution comprises a photoinitiator and first color quantum dots;

providing a second color mixed solution, wherein the second color mixed solution comprises a photoinitiator and second color quantum dots;

coating a first color mixed solution on a substrate, and carrying out exposure and development to form a first color sub-pixel;

coating a second color mixed solution on the substrate, and carrying out exposure and development to form a second color sub-pixel;

wherein the first color quantum dot and the second color quantum dot are selected from any one of the quantum dots in the above embodiments.

The preparation method of the quantum dot light-emitting device provided by the disclosure further comprises the following steps:

providing a third color mixed solution, wherein the third color solution comprises a photoinitiator and third color quantum dots;

coating a third color mixed solution on the substrate, and carrying out exposure and development to form a third color sub-pixel;

wherein the quantum dots of the third color are selected from the quantum dots in any of the above embodiments.

In the present disclosure, the first color, the second color, and the third color are only illustrated as being different from each other, but specific representative colors thereof are not particularly limited.

The disclosure also provides a display device comprising the quantum dot light-emitting device. The display device disclosed by the disclosure can be an electronic device such as a mobile phone, a tablet computer, a television and the like, which are not listed.

Quantum dot preparation examples

1. Example of Synthesis of coordination fragment

(1) Initiator for the synthesis of Atom Transfer Radical Polymerization (ATRP):

the synthesis route is as follows:

specific synthetic methods can be found in the literature: eugene et al, Macromolecules,2008,41, 5082; lonsdale et al, Macromolecules,2010,43, 3331; s.ye et al soft matter, 2016,15, 9520.

(2) Synthesis of coordination fragments

Polymerizing olefin by ATRP by using the ATRP initiator obtained in the step (1) to obtain a branched chain polymer:

the synthesis route is as follows:

where Rac-pre represents a precursor that can be subsequently used to form the Rac group in the linker, Rac-pre, and the methylene group to which it is attached, together serve to form the Rac group upon attachment to the linker. The duration of the polymerization reaction is related to the degree of polymerization (or molecular weight) of the obtained molecules, and the control time can control the synthesis of products with different molecular weights. Rqx (including Rq1, Rq2, etc.) and Rcx (including Rc1, Rc2, etc.) represent a plurality of molecular groups (not less than 1 species), which may be the same or different, and since the polymerization reaction is a random polymerization reaction, the relative spatial positions of the different repeating units in the resulting polymer molecule are random and are not limited to the products drawn in the reaction formulae.

(3) Performing a ring closing reaction on the functional group at the tail end of the obtained linear molecule to obtain a ring-shaped coordination fragment, wherein the reaction path is as follows:

similarly, Rqx (including Rq1, Rq2, etc.) and Rcx (including Rc1, Rc2, etc.) represent a plurality of molecular groups (not less than 1 species), which may be the same or different, and since the polymerization reaction of the previous stage is a random polymerization reaction, the relative spatial positions of the different repeating units in the resulting cyclic molecular chain are random and are not limited to the products plotted in the reaction formula.

The above final synthetic product is equivalent to

2. Coordination fragment, linker fragment, crosslinking group linkage

Taking the connecting segment containing polyethylene glycol chain or polyethylene oxide chain as an example, the ligand molecules with different lengths and different crosslinking groups are obtained as follows:

a first ligand:

second ligand

Third ligand

In each of the above formulae, A' represents a coordination fragment wherein R is removed ₀ Followed by a segment.

Rac-pre' represents a precursor that can be subsequently formed to form the Rac group used in the linker fragment.

In the formula, R ₀ 、Rac、L ₀ 、L ₂ X2, x3 may be selected from any structure or value of the above embodiments.

With R ₀ Is ethylene and Rac is

Is as follows, L ₀ Is linear hexamethylene, L ₂ For the example of-O-, the structure forming the third ligand is as follows:

3. ligand exchange to obtain quantum dots

And exchanging the ligand molecules to the surface of the common quantum dot in a ligand exchange mode to obtain the quantum dot material with the photosensitive crosslinking effect. The patterned quantum dot light-emitting layer can be prepared through photoetching and matched development processes.

Specific methods for ligand exchange can be referred to as follows: volatilizing a solvent (such as blow drying, suction drying, rotary evaporation and the like) of a synthesized common quantum dot solution (generally, the oil phase quantum dot is an oil phase quantum dot, ligand molecules are oleic acid, oleylamine, octylamine, mercaptan, trioctylphosphine oxide and the like, and a solvent is hexane, heptane, octane and the like, and the like), and adding toluene (or solvents such as xylene, chloroform, dichloromethane and the like, or mixed solvents thereof) to dissolve the quantum dot again into a quantum dot solution of 5 mg/mL-30 mg/mL; preferably, 1-5 mL of the re-dissolved quantum dot solution is taken, 50-2000 mg of the ligand molecule is added, and the mixture is stirred for 4-8 hours at normal temperature, so that the ligand molecule and the common quantum dot are fully coordinated or bonded, namely, the ligand exchange is fully carried out. And dropwise adding the solution into a methanol solution with the volume 10 times that of the solution, centrifuging the precipitate, and re-dissolving the precipitate in a solvent such as toluene to obtain a quantum dot solution with photosensitive characteristics.

Forming quantum dot luminous layer by photoetching process

1) Providing a first color mixed solution, a second color mixed solution and a third color mixed solution, wherein each color mixed solution comprises a photoinitiator and quantum dots with respective corresponding colors, and the quantum dots can be prepared by adopting the method in the embodiment;

2) coating mixed solutions with different colors on a substrate, and carrying out exposure treatment to crosslink carbon-carbon double bonds in crosslinkable groups in the quantum;

3) and carrying out development treatment to form the quantum dot light-emitting layer.

The steps 2) and 3) may specifically include the following operations:

as shown in fig. 1 to 2, a first color mixed solution is coated on a substrate 1 to form a first color quantum dot film layer 21, a first patterning (Photo Mask) process is added, and ultraviolet light is used to expose the whole; then, one or more mixed solvents of ethanol, isopropanol, propanol, n-butanol, DMF and DMSO are used as developers for washing and developing; after development, the substrate is again heated in an environment of 90 ℃ for 120 seconds to remove the developer, forming the first color sub-pixel 211.

As shown in fig. 3 to 4, a second color mixed solution is coated to form a second color quantum dot film layer 22, a second Photo Mask is added, the whole is exposed by ultraviolet light, and then a second color sub-pixel 221 is formed by development and fixation;

as shown in fig. 5 to 6, a third color mixed solution is finally coated to form a third color quantum dot film layer 23, a third Photo Mask is added, the whole is exposed by ultraviolet light, and then the third color sub-pixel 231 is formed by development and fixation.

The quantum dots react after exposure as follows:

(1) first ligand crosslinking

The first ligand comprises a crosslinkable group, and crosslinking is carried out on the surface of the quantum dot body.

(2) Second ligand crosslinking

Or

The second ligand comprises two crosslinkable groups, and crosslinking can occur between the surface of the quantum dot body and the quantum dot body.

(3) Third ligand

The third ligand comprises three crosslinkable groups, crosslinking occurs primarily between the quantum dot bodies.

In each of the above cross-linked types, QD represents a quantum dot body,

the connecting fragment is shown.

Example of preparation of display Panel

The display panel comprises a quantum dot light-emitting device, wherein the quantum dot light-emitting device comprises an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, an electron injection layer and a cathode which are sequentially stacked.

The preparation method of the display panel specifically comprises the following steps:

cleaning the transparent substrate by adopting a standard method, sequentially depositing grid metal Mo200nm, and patterning; gate dielectric SiO ₂ 150 nm; the active layer IGZO40nm is patterned; source and drain electrode metal Mo200nm, and patterning; passivation layer SiO ₂ 300nm and patterning; the pixel electrode ITO is 40nm and is patterned; finally, depositing an acrylic material in a spin coating manner, photoetching and curing to form a pixel defining layer with the thickness of about 1.5um to form a TFT backboard;

and before preparing a quantum dot light-emitting device (QD-LED), treating the surface of the TFT backboard by adopting plasma.

The hole injection layer and the hole transport layer are prepared by spin coating, such as respectively spin coating PEDOT (poly-3, 4-ethylenedioxy-CO)Thiophene(s)): PSS (polystyrene sulfonic acid), TFB, and the like; the whole thickness is 50-100 nm.

The method comprises the steps of forming a quantum dot light-emitting layer by adopting the photoetching process, specifically coating a first color mixed solution, adding a first Photo Mask, carrying out overall exposure by adopting ultraviolet light, and then developing and fixing to form a first color sub-pixel; coating a second color mixed solution, adding a second Photo Mask, carrying out overall exposure by adopting ultraviolet light, and then developing and fixing to form a second color sub-pixel; and finally, coating a third color mixed solution, adding a third Photo Mask, carrying out overall exposure by adopting ultraviolet light, and then developing and fixing to form a third color sub-pixel.

An electron transport layer and an electron injection layer, such as ZnO nanoparticles, are formed by spin coating or evaporation.

And (3) evaporating a cathode metal thin layer, wherein the cathode can adopt an Al layer and the like and is about 500-1000nm, and after evaporation, packaging and cutting are carried out to complete the preparation of the whole display panel.

It should be noted that although the various steps of the methods of the present disclosure are depicted in the drawings in a particular order, this does not require or imply that these steps must be performed in this particular order, or that all of the depicted steps must be performed, to achieve desirable results. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step execution, and/or one step broken down into multiple step executions, etc., are all considered part of this disclosure.

It is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of the components set forth in the specification. The present disclosure is capable of other embodiments and of being practiced and carried out in various ways. The foregoing variations and modifications are within the scope of the present disclosure. It should be understood that the disclosure disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present disclosure. The embodiments of this specification illustrate the best mode known for carrying out the disclosure and will enable those skilled in the art to utilize the disclosure.

Claims

1. A quantum dot, comprising:

a quantum dot body;

m1 and m2 are independently selected from any integer of 1-4, and m1 < m 2.

2. The quantum dot of claim 1, further comprising:

Y ₃ to join fragments, Y ₂ Connection X ₂ And the attachment Z ₂ The length of the chain between the sites of (a) is less than Y ₃ Connection X ₃ And the attachment Z ₃ The length of the strand between the sites of (a);

Z ₃ m3 represents Z for a crosslinkable group ₃ The number of (2);

m3 is selected from any integer of 1-4, and m2 < m 3.

3. The quantum dot of claim 1 or 2, wherein: the coordination fragment is selected from a structure shown as a formula X-1 or a formula X-2:

wherein the content of the first and second substances,

represents a chemical bond;

M ₁ 、M ₂ 、M ₃ 、M ₄ and M ₅ Each independently selected from hydrogen and a structure represented by formula M-1, and M ₁ And M ₂ One and only one of them is selected from the structures shown by the formula M-1, and M ₃ And M ₄ Wherein only one is selected from those represented by the formula M-1Structure;

dx is selected from a ring-closing reactive group for reacting

A ring-closing reaction is carried out to form a structure shown as a formula X-2;

4. The quantum dot of claim 3, wherein Rcx is selected from the group consisting of alkylene groups having 1 to 6 carbon atoms or the following structures:

5. The quantum dot of claim 3, wherein R is ₀ Selected from alkylene groups having 1 to 6 carbon atoms or the group consisting of the following structures:

6. The quantum dot of claim 3, wherein Dx is selected from the group consisting of:

wherein n5 is selected from any integer from 1 to 18;

R ₀ ' selected from alkylene groups having 1 to 8 carbon atoms,

R ₁ ’、R ₂ ' each is independently selected from hydrogen, alkylene having 1 to 8 carbon atoms, and R ₁ ’、R ₂ At least one of them is selected from alkylene groups having 1 to 8 carbon atoms, L ₁ ' is selected from amide bond, ester bond, and nitrogen-containing heterocycle.

7. The quantum dot of claim 3, wherein the coordination fragment is selected from the group consisting of the following structures:

8. the quantum dot of claim 1 or 2, wherein the linker fragment is selected from the group consisting of

represents a chemical bond;

L ₂ selected from the group consisting of a single bond and-O-;

h is selected from C, Si or an alkane chain having multiple attachment sites;

Q ₁ 、Q ₂ 、Q ₃ each independently selected from hydrogen, alkyl having 1 to 6 carbon atoms or a structure represented by the formula Q-1, and Q ₁ 、Q ₂ 、Q ₃ At least one of them is selected from the structures shown in the formula Q-1;

rac and Rbc are respectively and independently selected from arylene with 6-12 carbon atoms, alkylidene with 1-8 carbon atoms and a structure shown as a formula R-2;

R ₃ 、R ₄ each independently selected from hydrogen, alkylene of 1 to 8 carbon atoms, and R ₃ 、R ₄ At least one of them is selected from alkylene groups having 1 to 8 carbon atoms, L ₄ Selected from amide bond, ester bond, and nitrogen-containing heterocycle.

9. The quantum dot of claim 8, wherein Rac and Rbc are each independently selected from the group consisting of alkylene groups having 1-6 carbon atoms or the following structures:

10. The quantum dot of claim 8, wherein H is selected from C, Si or the following structure:

wherein, # denotes the above structure for use with

11. The quantum dot of claim 8, wherein L is ₃ Selected from the group consisting of the following structures:

wherein x1 is selected from any integer from 1 to 8;

12. The quantum dot of claim 8, wherein L is ₀ Selected from the group consisting of the following structures:

x4 is selected from any integer from 2 to 20;

13. The quantum dot of claim 12, wherein L is ₀ Selected from the structures shown in the formula L-1, wherein x4 in the first ligand is selected from any integer from 2 to 14, and x4 in the second ligand is selected from any integer from 8 to 20; or

14. The quantum dot of claim 12, wherein when the quantum dot further comprises the third ligand;

L ₀ selected from the structures shown in the formula L-1, wherein x4 in the first ligand is selected from any integer from 2 to 8, x4 in the second ligand is selected from any integer from 8 to 14, and x4 in the third ligand is selected from any integer from 14 to 20; or

15. The quantum dot of claim 8, wherein L contained in the linker segment of the first ligand is L ₀ Is shorter than L contained in the linking fragment of the second ligand ₀ The chain length of (a);

16. The quantum dot of claim 8, wherein the linker segment is selected from the group consisting of:

17. A quantum dot according to claim 1 or 2, wherein the crosslinkable group is selected from the group consisting of structures according to formula Z-1 or formula Z-2:

wherein the content of the first and second substances,

represents a chemical bond;

the ring A is selected from an unsaturated five-membered ring or a six-membered ring containing at least one carbon-carbon double bond;

R ₈ selected from hydrogen, oxygen, hydroxyl, sulfydryl, amino, carboxyl, an alkane chain with 1-16 carbon atoms, an alkene chain with 2-10 carbon atoms and an arene structure with 6-20 carbon atoms;

n8 represents R ₈ The number of (2);

when ring a is a five-membered ring, n8 is selected from a positive integer of not more than 4;

18. The quantum dot of claim 17, wherein ring a is selected from the group consisting of:

19. the quantum dot of claim 17, wherein the crosslinkable group is selected from the group consisting of:

20. A quantum dot crosslinked material, comprising:

a first quantum dot selected from the quantum dots of any one of claims 1-19;

a second quantum dot selected from the quantum dots of any one of claims 1-19;

21. The quantum dot crosslink of claim 20, wherein when the first quantum dot and the second quantum dot further comprise a third ligand,

22. A method for preparing a quantum dot pattern, comprising:

providing a mixed solution of a photoinitiator and the quantum dot of any one of claims 1-19;

and carrying out development treatment to form the quantum dot pattern.

23. A quantum dot light-emitting layer comprising the quantum dot crosslinked material according to claim 20 or 21.

24. A quantum dot light emitting device comprising the quantum dot light emitting layer of claim 23.