Quantum dot composition, light-emitting element, display panel and preparation method therefor

Abstract

The present disclosure belongs to the technical field of display, and provides a quantum dot composition, a light-emitting element, a display panel and a preparation method therefor. The quantum dot composition comprises a quantum dot body, a ligand and a cross-linking agent, wherein the ligand and the quantum dot body are in coordinate bonding; one of the ligand and the cross-linking agent has a sulfhydryl group protected by a photolabile group; the photolabile group can be desorbed under illumination to release a sulfhydryl group, a sulfur radical or a sulfur anion; when the released sulfhydryl group, sulfur radical or sulfur anion is located on the cross-linking agent, the released sulfhydryl group, sulfur radical or sulfur anion is used for coordinate bonding to the quantum dot body or used for reacting with the ligand to form a chemical bond; and when the released sulfhydryl group, sulfur radical or sulfur anion is located on the ligand, the released sulfhydryl group, sulfur radical or sulfur anion is used for reacting with the cross-linking agent to form a chemical bond. The quantum dot composition can be used to prepare a quantum dot layer of a display panel by means of a photolithography process. (FIG. 1)

Description

Quantum dot composition, light-emitting element, display panel and preparation method thereof

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to PCT International Patent Application No. PCT / CN2024 / 076770 entitled “Quantum dot composition, light-emitting element, display panel and preparation method thereof” filed on February 7, 2024, the entire contents of which are incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of display, and in particular, to a quantum dot composition, a light-emitting element, a display panel and a preparation method thereof. BACKGROUND

[0004] With the in-depth development of quantum dot preparation technology, the stability and light-emitting efficiency of quantum dots are continuously improved, the research of quantum dot electroluminescent diode (QLED) is continuously deepened, and the application prospect of QLED in the display field is increasingly bright, but the efficiency of QLED has not reached the level of mass production. One of the important reasons is that the high-resolution patterning technology of QLED has not made a breakthrough. The inorganic nanoparticle characteristics of quantum dots make it impossible to form a film by evaporation and patterning, and it is difficult to achieve high resolution by inkjet printing.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art.

[0006] SUMMARY

[0007] The purpose of the present disclosure is to overcome the shortcomings of the prior art, and to provide a quantum dot composition, a light-emitting element, a display panel and a preparation method thereof, for preparing a display panel by a photolithography process.

[0008] According to one aspect of the present disclosure, a quantum dot composition is provided, comprising a quantum dot body, a ligand, and a cross-linking agent;

[0009] The ligand is coordinately connected with the quantum dot body;

[0010] One of the ligand and the cross-linking agent has a mercapto group protected by a photolabile group;

[0011] The photolabile group can be removed under light to release a mercapto group, a sulfur radical or a sulfur anion;

[0012] When the released thiol, thyl radical or thiolate is on the crosslinker, it is used to coordinate to the quantum dot body or to react with the ligand to form a chemical bond; when the released thiol, thyl radical or thiolate is on the ligand, it is used to react with the crosslinker to form a chemical bond.

[0013] [According to Rule 26 Correction 11.09.2025] According to an embodiment of the present disclosure, the photolabile group is selected from the following substituents:

[0014] wherein Ar1 is selected from aryl having a nitro group or a hydroxyl group, heteroaryl having a nitro group or a hydroxyl group; R1, R2 and R3 are each independently selected from hydrogen, deuterium, alkyl having 1-6 carbon atoms.

[0015] [According to Rule 26 Correction 11.09.2025] According to an embodiment of the present disclosure, the photolabile group is selected from the following substituents:

[0016] wherein R5 is selected from hydrogen, deuterium, alkoxy having 1-8 carbon atoms.

[0017] According to an embodiment of the present disclosure, the crosslinker has a plurality of the thiol protected by the photolabile group; the ligand has an active alkenyl group, the active alkenyl group comprising an alkenyl group and an electron-withdrawing group connected to the alkenyl group.

[0018] According to an embodiment of the present disclosure, the crosslinker has a first connecting group, and the thiol protected by the photolabile group is connected to the first connecting group.

[0019] According to an embodiment of the present disclosure, the ligand has a structural formula of A-B-C-D or A-B-D; wherein A is a coordination group capable of coordinating with the quantum dot; B is a second connecting group; C is a carrier transport adjusting group; and D is the active alkenyl group.

[0020] According to an embodiment of the present disclosure, the ligand has the thiol protected by the photolabile group; and the crosslinker has a plurality of active alkenyl groups, the active alkenyl group comprising an alkenyl group and an electron-withdrawing group connected to the alkenyl group.

[0021] According to an embodiment of the present disclosure, the crosslinker has a first connecting group, and the active alkenyl group is connected to the first connecting group.

[0022] According to an embodiment of the present disclosure, the ligand has a structural formula of A-B-C-D or A-B-D; wherein A is a coordinating group capable of coordinating with the quantum dot; B is a second linking group; C is a carrier transport regulating group; and D is the thiol group protected by the photolabile group.

[0023] According to an embodiment of the present disclosure, the coordinating group has an amino group, a carboxylic acid group, a thiol group, two thiol groups, a phosphine group, or a phosphine oxide group.

[0024] According to an embodiment of the present disclosure, the active alkenyl group is selected from the following groups:

[0025] wherein R4 is selected from hydrogen, deuterium, an alkyl group of 1-6 carbon atoms; and EWG is an electron-withdrawing group.

[0026] According to an embodiment of the present disclosure, the active alkenyl group is selected from the following groups:

[0027] According to an embodiment of the present disclosure, the cross-linking agent has a plurality of the thiol groups protected by the photolabile group.

[0028] In the quantum dot body and the ligand, the mass ratio of the ligand is not greater than 30%.

[0029] According to an embodiment of the present disclosure, in the quantum dot body and the ligand, the mass ratio of the ligand is not greater than 15%.

[0030] According to an embodiment of the present disclosure, in the quantum dot body and the ligand, the mass ratio of the ligand is between 15% and 30%.

[0031] The acidity of the ligand is less than the acidity of the thiol group after the deprotection of the photolabile group.

[0032] According to an embodiment of the present disclosure, the ligand is selected from oleic acid, oleylamine, octanethiol, and dodecanethiol.

[0033] According to an embodiment of the present disclosure, the mass content of the cross-linking agent is 1%-5%.

[0034] According to a second aspect of the present disclosure, a light-emitting element is provided, wherein the light-emitting element comprises a quantum dot layer; the quantum dot layer has quantum dot bodies connected to each other by an organic material.

[0035] The organic material includes ligand groups coordinated with the quantum dot bodies and cross-linking groups connected with the plurality of ligand groups, and a sulfide structure is formed between the ligand groups and the cross-linking groups; or the organic material has a plurality of mercapto groups, sulfur free radicals or sulfur negative ions and is coordinated with the plurality of quantum dot bodies through the mercapto groups, the sulfur free radicals or the sulfur negative ions.

[0036] According to a third aspect of the present disclosure, a display panel is provided, wherein the display panel comprises the light emitting element described above.

[0037] According to a fourth aspect of the present disclosure, a method for manufacturing a display panel is provided, comprising: sequentially forming quantum dot layers of at least two sub-pixels on a surface of a substrate by a photolithography process; forming the quantum dot layer of any one of the sub-pixels comprises:

[0038] forming a quantum dot composition film layer on the surface of the substrate by using a quantum dot composition corresponding to the sub-pixel, the quantum dot composition being selected from the quantum dot compositions described above;

[0039] exposing and developing the quantum dot composition film layer corresponding to the sub-pixel to obtain the quantum dot layer of the sub-pixel;

[0040] wherein the quantum dots in the quantum dot layers of different sub-pixels are different.

[0041] According to an embodiment of the present disclosure, the method for manufacturing the display panel further comprises:

[0042] forming a hole transport layer of each of the sub-pixels before forming the quantum dot layer.

[0043] According to an embodiment of the present disclosure, the method for manufacturing the display panel further comprises:

[0044] forming an electron transport layer of each of the sub-pixels after forming the quantum dot layer of each of the sub-pixels.

[0045] According to an embodiment of the present disclosure, the forming of the quantum dot composition film layer on the surface of the substrate by using the quantum dot composition corresponding to the sub-pixel comprises:

[0046] forming the quantum dot composition film layer on the surface of the substrate by using the quantum dot composition corresponding to the sub-pixel through a coating process.

[0047] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the present disclosure. It is apparent that the drawing in the following description is only some embodiments of the present disclosure, and other drawings can be obtained by those of ordinary skill in the art without creative effort on the basis of these drawings.

[0049] FIG. 1 is a flow diagram of preparing a quantum dot layer in one embodiment of the present disclosure.

[0050] FIG. 2 is a structural diagram of a backplane having a pixel definition layer on the surface thereof in one embodiment of the present disclosure.

[0051] FIG. 3 is a structural diagram of forming a green quantum dot composition layer on the surface of the backplane in one embodiment of the present disclosure.

[0052] FIG. 4 is a structural diagram of forming a green quantum dot layer on the surface of the backplane in one embodiment of the present disclosure.

[0053] FIG. 5 is a structural diagram of forming a blue quantum dot composition layer on the surface of the backplane in one embodiment of the present disclosure.

[0054] FIG. 6 is a structural diagram of forming a blue quantum dot layer on the surface of the backplane in one embodiment of the present disclosure.

[0055] FIG. 7 is a structural diagram of forming a red quantum dot composition layer on the surface of the backplane in one embodiment of the present disclosure.

[0056] FIG. 8 is a structural diagram of forming a red quantum dot layer on the surface of the backplane in one embodiment of the present disclosure.

[0057] FIG. 9 is a UV excitation result diagram of a glass substrate after coating, exposing and developing with a control quantum dot composition.

[0058] FIG. 10 is a UV excitation result diagram of a glass substrate after coating, exposing and developing with an experimental quantum dot composition. DETAILED DESCRIPTION

[0059] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations can be implemented in any

[0060] Like reference numerals can be used to describe like elements throughout the specification and its figures. It should be appreciated that the example implementations can be implemented in various manners. In the following description, numerous specific details are set forth to provide an understanding of the example implementations. However, it will be apparent to those skilled in the art that the example implementations can be practiced without one or more of these specific details. In other instances, well-known structures, materials, and operating

[0061] When a structure is "on" another structure, it can mean that the structure is formed integrally with the other structure, or that the structure is "directly" on the other structure, or that the structure is "indirectly" on the other structure by having another structure therebetween.

[0062] The terms "one", "a", "an", "the", and "at least one" are used to indicate that "one or more" of the specified element(s) / component(s) / etc. is(are) present with the understanding that one or more of those element(s) / component(s) / etc. can be present; the terms "comprising", "having" and "including" are used to mean "including but not limited to" with the understanding that there can be additional elements / components / etc. present; and the use of "first", "second", and "third" etc. are used only to distinguish one element / component / etc. from another and is not meant to imply a relative importance or a creating a hierarchy.

[0063] In the related art, quantum dots cannot be implemented in the same evaporation manner as the self-luminous OLED due to the disadvantage of being easily affected by heat and moisture, and can only be implemented by inkjet printing. However, it is difficult to achieve high resolution by inkjet printing.

[0064] To solve the above problems, the present disclosure provides a quantum dot composition, which comprises quantum dot bodies, ligands, and a cross-linking agent; the ligands are coordinately connected to the quantum dot bodies; one of the ligands and the cross-linking agent has a thiol group protected by a photoremovable group; the photoremovable group can release a reactive sulfur group under light, which can chemically react with other components in the quantum dot composition to form a chemical bond. For example, the photoremovable group can release a thiol group, a sulfur radical, or a sulfur anion under light. When the released thiol group, sulfur radical, or sulfur anion is on the cross-linking agent, the released thiol group, sulfur radical, or sulfur anion is used to coordinately connect to the quantum dot bodies or to react with the ligands to form a chemical bond; when the released thiol group, sulfur radical, or sulfur anion is on the ligand, the released thiol group, sulfur radical, or sulfur anion is used to react with the cross-linking agent to form a chemical bond.

[0065] In the quantum dot composition provided by the present disclosure, the quantum dot ligand or the cross-linking agent contains a thiol group protected by a photoremovable protecting group (PPG). When the quantum dot composition is applied, the photoremovable protecting group PPG can be removed under light to release a thiol group, a sulfur radical, or a sulfur anion. The released thiol group, sulfur radical, or sulfur anion can further react with other components in the quantum dot composition, so that the quantum dot bodies can form a quantum dot layer through cross-linking. For example, the released thiol group, sulfur radical, or sulfur anion on the cross-linking agent can directly coordinately connect to the coordination center on the surface of the quantum dot bodies. For another example, the released thiol group, sulfur radical, or sulfur anion on the cross-linking agent can also react with the quantum dot ligand. For another example, the released thiol group, sulfur radical, or sulfur anion on the quantum dot ligand can react with the cross-linking agent. Therefore, the quantum dot composition of the present disclosure can be cross-linked under light, but not cross-linked under non-illumination, which makes the film layer prepared by the quantum dot composition be patterned by a photolithography process. When a display panel uses the quantum dot composition of the present disclosure and uses a photolithography process to prepare a quantum dot layer, the resolution constraint of inkjet printing can be reduced, thereby facilitating the improvement of the resolution of the display panel.

[0066] Quantum dots (QDs) are small-sized inorganic semiconductor nanoparticles with a size close to or smaller than the exciton Bohr radius of the particle. Quantum dots are prone to aggregation due to their small size and large specific surface area, and have many surface defects. Therefore, the surface of the quantum dots is usually modified with ligands to form modified quantum dots. In the embodiments of the present disclosure, the unmodified inorganic quantum dots are referred to as quantum dot bodies, and the materials modified on the quantum dot bodies are referred to as ligands. The ligands are generally organic ligands. The organic ligands not only play a protective role but also make the quantum dots have good solubility in solution. The migration of carriers (electrons and holes) in the quantum dots is limited to the interior of the quantum dots, which makes the quantum dots have unique optical and electrical properties. Due to the unique size-dependent properties, the light absorption and emission properties of the quantum dots can be easily adjusted by controlling the particle size, shape or surface structure.

[0067] The quantum dots of the present disclosure can be semiconductor nanocrystals and can have various shapes. For example, the quantum dots can be spherical, conical, multi-armed and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. Here, the aspect ratio (length:diameter ratio; length:width ratio) of the quantum rods can be greater than about 1. For example, the aspect ratio of the quantum rods can be 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 rods can 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.

[0068] The quantum dot body can have a particle diameter (for non-spherical shapes, the average maximum particle length) of, for example, about 1 nm to about 100 nm, about 1 nm to about 80 nm, about 1 nm to about 50 nm, or about 1 nm to 20 nm, or 1 nm to 10 nm.

[0069] Exemplary, the band gap of the quantum dot body can be controlled according to the size and composition of the quantum dot body, and thus the wavelength of light emission can be controlled. For example, as the size of the quantum dot body increases, the quantum dot body can have a narrow band gap and thus be configured to emit light in a relatively long wavelength region, while as the size of the quantum dot body decreases, the quantum dot body can have a wide band gap and thus be configured to emit light in a relatively short wavelength region. Exemplary, the quantum dot body can 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 can be configured to emit second color light, third color light, or first color light, the second color light can have a peak emission wavelength (λmax) of, for example, in the range of about 430 nm to about 480 nm, the third color light can have a peak emission wavelength (λmax) of, for example, in the range of about 600 nm to about 650 nm, and the first color light can have a peak emission wavelength (λmax) of, for example, in the range of about 520 nm to about 560 nm, but not limited thereto.

[0070] Exemplary, the average particle size of the quantum dot body configured to emit second color light can be less than or equal to about 4.5 nm; for example, the average particle size of the quantum dot body configured to emit second color light can be less than or equal to about 4.3 nm, less than or equal to about 4.2 nm, less than or equal to about 4.1 nm, or less than or equal to about 4.0 nm. Within the range, the average particle size of the quantum dot body can be in the range of about 2.0 nm to about 4.5 nm, for example, in the range of about 2.0 nm to about 4.3 nm, in the range of about 2.0 nm to about 4.2 nm, in the range of about 2.0 nm to about 4.1 nm, or in the range of about 2.0 nm to about 4.0 nm.

[0071] Exemplary, the quantum dot body can have a quantum yield of 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%.

[0072] The quantum dot body can have a relatively narrow full width at half maximum (FWHM). Here, the FWHM is the width of the wavelength corresponding to half of the peak absorption point, and when the FWHM is narrow, light can be configured to be emitted in a narrow wavelength region, and a higher color purity can be obtained. For example, the quantum dot body can have a FWHM of less than or equal to about 50 nm, less than or equal to about 49 nm, less than or equal to about 48 nm, less than or equal to about 47 nm, less than or equal to about 46 nm, less than or equal to about 45 nm, less than or equal to about 44 nm, less than or equal to about 43 nm, less than or equal to about 42 nm, less than or equal to about 41 nm, less than or equal to about 40 nm, less than or equal to about 39 nm, less than or equal to about 38 nm, less than or equal to about 37 nm, less than or equal to about 36 nm, less than or equal to about 35 nm, less than or equal to about 34 nm, less than or equal to about 33 nm, less than or equal to about 32 nm, less than or equal to about 31 nm, less than or equal to about 30 nm, less than or equal to about 29 nm, or less than or equal to about 28 nm. For example, within the range, it can have a FWHM of about 2 nm to about 49 nm, about 2 nm to about 48 nm, about 2 nm to about 47 nm, about 2 nm to about 46 nm, about 2 nm to about 45 nm, about 2 nm to about 44 nm, about 2 nm to about 43 nm, about 2 nm to about 42 nm, about 2 nm to about 41 nm, about 2 nm to about 40 nm, about 2 nm to about 39 nm, about 2 nm to about 38 nm, about 2 nm to about 37 nm, about 2 nm to about 36 nm, about 2 nm to about 35 nm, about 2 nm to about 34 nm, about 2 nm to about 33 nm, about 2 nm to about 32 nm, about 2 nm to about 31 nm, about 2 nm to about 30 nm, about 2 nm to about 29 nm, or about 2 nm to about 28 nm.

[0073] By way of example, the quantum dot body can comprise a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a IV semiconductor, a I-III-VI semiconductor compound, a I-II-IV-VI semiconductor compound, a II-III-V semiconductor compound, or a combination thereof. By way of example, the II-VI semiconductor compound can be selected from a binary semiconductor compound such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or a mixture thereof; a ternary semiconductor compound such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or a mixture thereof; and a quaternary semiconductor compound such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or a mixture thereof, but is not limited thereto. By way of example, the III-V semiconductor compound can be selected from a binary semiconductor compound such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or a mixture thereof; a ternary semiconductor compound such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or a mixture thereof; and a quaternary semiconductor compound such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or a mixture thereof, but is not limited thereto. By way of example, the IV-VI semiconductor compound can be selected from a binary semiconductor compound such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or a mixture thereof; a ternary semiconductor compound such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or a mixture thereof; and a quaternary semiconductor compound such as SnPbSSe, SnPbSeTe, SnPbSTe, or a mixture thereof, but is not limited thereto.The Group IV semiconductor may, for example, be selected from the group consisting of elemental (monatomic) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but is not limited thereto. The Group I-III-VI semiconductor compound may, for example, be CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but is not limited thereto. The Group I-II-IV-VI semiconductor compound may, for example, be CuZnSnSe, CuZnSnS, or mixtures thereof, but is not limited thereto. The Group II-III-V semiconductor compound can include, for example, InZnP, but is not limited thereto.

[0074] The quantum dot body can include the elemental semiconductor, the binary semiconductor compound, the ternary semiconductor compound, or the quaternary semiconductor compound at a substantially uniform concentration or a locally varying concentration profile.

[0075] For example, the quantum dot body can include a cadmium (Cd)-free quantum dot body. A cadmium (Cd)-free quantum dot body is a quantum dot body that does not include cadmium (Cd). Cadmium (Cd) can cause serious environmental / health problems, and in many countries, cadmium (Cd) is an element that is restricted in accordance with the Restriction of Hazardous Substances Directive (RoHS).

[0076] For example, the quantum dot body can be a semiconductor compound including indium (In), and at least one of zinc (Zn) and phosphorus (P). For example, the quantum dot body can be an In-P semiconductor compound and / or an In-Zn-P semiconductor compound.

[0077] For example, the quantum dot body can be a semiconductor compound including indium (In), and at least one of zinc (Zn) and phosphorus (P). For example, the quantum dot body can be an In-P semiconductor compound and / or an In-Zn-P semiconductor compound.

[0078] For example, the quantum dot body can be a semiconductor compound including indium (In), and at least one of zinc (Zn) and phosphorus (P). For example, the quantum dot body can be an In-P semiconductor compound and / or an In-Zn-P semiconductor compound.

[0079] The quantum dot body can have a core-shell structure. For example, the core and shell of the quantum dot body can have an interface, and an element of at least one of the core or the shell in the interface can have a concentration gradient, where the concentration of the element of the shell decreases toward the core. For example, the material composition of the shell of the quantum dot body has a higher band gap than the material composition of the core of the quantum dot body, and thus the quantum dot body can exhibit quantum confinement effects.

[0080] The quantum dot body can have a quantum dot core and a multi-layer quantum dot shell surrounding the core. Here, the multi-layer shell has at least two shells, where each shell can be of a single composition, an alloy, and / or have a concentration gradient.

[0081] For example, a shell of the multi-layer shell distal from the core can have a higher band gap than a shell proximal to the core, and thus the quantum dot body can exhibit quantum confinement effects.

[0082] For example, a quantum dot body having a core-shell structure can include, for example: a core including a first semiconductor compound including zinc (Zn), and at least one of tellurium (Te) and selenium (Se); and a shell disposed on at least a portion of the core and having a composition different from a composition of the core, the shell including a second semiconductor compound.

[0083] For example, the first semiconductor compound can be a Zn-Te-Se based semiconductor compound including zinc (Zn), tellurium (Te), and selenium (Se), for example, a Zn-Se based semiconductor compound including a small amount of tellurium (Te), for example, a semiconductor compound represented by ZnTexSei-x, where x is greater than about 0 and less than or equal to 0.05.

[0084] For example, in a first semiconductor compound based on Zn-Te-Se, the molar amount of zinc (Zn) can be higher than the molar amount of selenium (Se), and the molar amount of selenium (Se) can be higher than the molar amount of tellurium (Te). For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to selenium (Se) can 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 0.018, 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 0.01. For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to zinc (Zn) 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.

[0085] 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 Group II-VI semiconductor compound, the Group III-V semiconductor compound, the Group IV-VI semiconductor compound, the Group IV semiconductor, the Group I-III-VI semiconductor compound, the Group I-II-IV-VI semiconductor compound, and the Group II-III-V semiconductor compound are the same as described above.

[0086] For example, the second semiconductor compound can 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 can include at least one inner shell disposed proximate 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 can have a concentration gradient of one composition, and for example, an amount of sulfur (S) can increase away from the core.

[0087] For example, a quantum dot body having a core-shell structure can include: a core including a third semiconductor compound including indium (In), and at least one of zinc (Zn) and phosphorous (P); and a shell disposed on at least a portion of the core and including a fourth semiconductor compound having a different composition than the core.

[0088] In the third semiconductor compound based on In-Zn-P, a molar ratio of zinc (Zn) to indium (In) can be greater than or equal to about 25. For example, in the third semiconductor compound based on In-Zn-P, a molar ratio of zinc (Zn) to indium (In) can 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, in the third semiconductor compound based on In-Zn-P, a molar ratio of zinc (Zn) to indium (In) can be less than or equal to about 55, for example, 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.

[0089] 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 Group II-VI semiconductor compound, the Group III-V semiconductor compound, the Group IV-VI semiconductor compound, the Group IV semiconductor, the Group I-III-VI semiconductor compound, the Group I-II-IV-VI semiconductor compound, and the Group II-III-V semiconductor compound are the same as described above.

[0090] For example, the fourth semiconductor compound can 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 can include at least one inner shell disposed proximate 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 can include the fourth semiconductor compound ZnS, ZnSe, or ZnSeS.

[0091] In the present disclosure, for the sake of brevity and clarity, all the schematic diagrams of quantum dot bodies referred to throughout the text are represented by a circle, and the quantum dot body materials actually used are not limited to spherical quantum dots, including but not limited to quantum dot materials of any geometric shape such as spherical, ellipsoidal, polyhedral, rod-shaped, cross-shaped, ring-shaped, etc.

[0092] In some embodiments of the present disclosure, the photodegradable group is selected from the following substituents:

[0093] wherein Ar1 is selected from an aryl group having a nitro group or a hydroxyl group, a heteroaryl group having a nitro group or a hydroxyl group; R1, R2 and R3 are each independently selected from hydrogen, deuterium, an alkyl group having 1-6 carbon atoms. represents a chemical bond. The photodegradable group can disintegrate under light conditions to release a mercapto group, a sulfur radical or a sulfur anion.

[0094] [Corrected according to Rule 26 11.09.2025] In an embodiment of the present disclosure, the photodegradable group is selected from the following substituents:

[0095] wherein R5 is selected from hydrogen, deuterium, an alkoxy group having 1-8 carbon atoms, for example, R5 is selected from hydrogen, deuterium, -OC n H 2n+1 (n is a positive integer from 1 to 8). In an example, R5 is selected from hydrogen, deuterium, methoxy, ethoxy, propoxy, isopropoxy, tert-butoxy, etc.

[0096] It can be understood that the photodegradable group has different structures, and the wavelength of light required for its deprotection (i.e., the exposure wavelength) is different. For example, the exposure wavelength of PPG1 can be 320 nm or 365 nm; the exposure wavelength of PPG2 and PPG3 can be 254 nm; the exposure wavelength of PPG4 and PPG5 can be 365 nm; the exposure wavelength of PPG6 can be 405 nm or 436 nm. The light absorption wavelength and absorbance of the photodegradable group can also be adjusted by adding or subtracting substituents on the photodegradable group to adapt to a wider range of process flows.

[0097] In some embodiments of the present disclosure, the crosslinker has a plurality of the thiol groups protected by the photocleavable groups; that is, the crosslinker contains two or more thiol groups protected by the photocleavable groups. The quantum dot ligand has an active alkenyl group, which includes an alkenyl group and an electron-withdrawing group connected to the alkenyl group. The crosslinker releases the thiol group, the sulfur radical or the sulfur anion by removing the protecting group (the photocleavable group) under light irradiation, which can react with the alkenyl group in the active alkenyl group to form a chemical bond. In this way, at least part of the crosslinker is crosslinked with the ligands on different quantum dot bodies, so that the quantum dot bodies are connected to each other.

[0098] In an example, the plurality of the thiol groups protected by the photocleavable groups can be linked by a first linking group. The first linking group can be a flexible segment or a rigid segment. Further, the rigid segment can be a hole-transporting or electron-transporting functional group, or a conjugated group facilitating hole and electron transport. For example, the rigid segment can include a triphenylamine structure, a carbazole structure or a fluorene structure.

[0099] The quantum dot layer using the quantum dot composition has the quantum dot bodies connected to each other by the organic material. The organic material includes the ligand group coordinated with the quantum dot body and the crosslinking group connected to the plurality of ligand groups, and a sulfide structure is formed between the ligand group and the crosslinking group. Among them, the ligand in the quantum dot composition serves as the ligand group of the organic material after reacting with the released thiol group, the sulfur radical or the sulfur anion, the first linking group of the crosslinker can form the crosslinking group of the organic material, and the ligand group and the crosslinking group are connected by the sulfide structure.

[0100] In an example, the quantum dot ligand has a structural formula of A-B-C-D or A-B-D; wherein A is a coordination group capable of coordinating with the quantum dot body; B is a second linking group; C is a carrier transport adjusting group; and D is the active alkenyl group.

[0101] For example, the coordination group can be selected from an amino group, a carboxylic acid group, a thiol group, a disulfide group, a phosphine group or a phosphine oxide group.

[0102] For example, the second linking group can be an alkyl chain containing 2-8 methylene groups, which can be a straight-chain alkyl chain or a branched-chain alkyl chain.

[0103] For example, the carrier transport adjusting group is selected from a triphenylamine structure or a carbazole structure. The carrier transport adjusting group is arranged in the quantum dot ligand so as to subsequently form a quantum dot layer with strong carrier transport capability. The triphenylamine structure or the carbazole structure facilitates hole transport.

[0104] [Amended according to Rule 26 11.09.2025] In one embodiment of the disclosure, the active alkenyl group is selected from the group consisting of:

[0105] wherein R4 is selected from the group consisting of hydrogen, deuterium, alkyl of 1 to 6 carbon atoms; and EWG is an electron withdrawing group.

[0106] [Amended according to Rule 26 11.09.2025] For example, the active alkenyl group is selected from the group consisting of:

[0107] [Amended according to Rule 26 11.09.2025] For example, the crosslinker contains two thiol groups protected by photocleavable groups, which can have the following reaction:

[0108] [Amended according to Rule 26 11.09.2025] In an embodiment of the disclosure, the crosslinker or ligand is represented by

[0109] [Amended according to Rule 26 11.09.2025] In reaction formula (1), the structure of the crosslinker can be:

[0110] [Amended according to Rule 26 11.09.2025] Optionally, the above crosslinker can be synthesized by the following method:

[0111] 2-(1-bromoethyl)-3-nitrobenzofuran (0.64 g, 2 mmol) and ethyl mercaptoacetate (0.24 g, 2 mmol) were dissolved in 10 mL of dichloromethane, zinc acetate (0.36 g, 2 mmol) was added, and stirred at 25°C for 24 hours. After that, 50 mL of a saturated sodium chloride solution was added to the reaction mixture, extracted with dichloromethane 3 times, dried by rotary evaporation, and purified by column chromatography. The intermediate 1 (0.47 g, yield 65%) was obtained. 1 H NMR δ (ppm): 8.57 (1H), 7.98 (1H), 7.67 (1H), 7.54 (1H), 7.31-7.40 (2H), 4.17 (2H), 3.92 (1H), 3.40 (2H), 1.58 (3H), 1.25 (3H).

[0112] ​​​Intermediate 1 (0.36 g, 1 mmol), sodium hydroxide (0.08 g, 2 mmol) in 10 mL of acetone, stirring at 40 °C for 4 hours, after dropping to room temperature, rotary evaporation to dryness, adding 50 mL of saturated sodium chloride solution, rotary evaporation to dryness after extracting three times with dichloromethane. Purification using column chromatography, rotary evaporation to dryness, to obtain intermediate 2 (0.2 g, yield 60%). 1 H NMR δ (ppm): 8.59 (1H), 7.97 (1H), 7.64 (1H), 7.56 (1H), 7.31-7.40 (2H), 3.90 (1H), 3.40 (2H), 1.58 (3H).

[0113] Intermediate 2 (0.166 g, 0.5 mmol), ethylene glycol (12.4 mg, 0.2 mmol) in 10 mL of dichloromethane, adding EDC (150 mg) (1-ethyl-(3-dimethylaminopropyl) carbodiimide), DMAP (50 mg) (4-dimethylaminopyridine), stirring at 25 °C for 12 hours, rotary evaporation to dryness, adding 50 mL of saturated sodium chloride solution, rotary evaporation to dryness after extracting three times with dichloromethane. Purification using column chromatography, rotary evaporation to dryness, to obtain compound 3 (68.8 g, yield 50%). 1 H NMR δ (ppm): 8.57 (2H), 7.98 (2H), 7.67 (2H), 7.54 (2H), 7.31-7.40 (4H), 4.31 (4H), 3.92 (2H), 3.40 (4H), 1.58 (6H).

[0114] In reaction formula (1), the structure of the quantum dot ligand can be:

[0115] wherein the coordinating group in the quantum dot ligand is a thiol group, the second linking group is the active alkenyl group is

[0116] In another example, the ligand in reaction formula (1) can also be:

[0117] wherein the coordinating group in the quantum dot ligand is a hydroxyl group, the second linking group is the active alkenyl group is

[0118] In the above examples, the crosslinking agent is taken as an example with two reactive functional groups. As follows, the crosslinking agent is taken as an example with three or more reactive functional groups.

[0119] [Rule 26 correction 11.09.2025] In one example, the crosslinker reacts with the ligand as follows:

[0120] [Rule 26 correction 11.09.2025] In this example, the crosslinker is:

[0121] [Rule 26 correction 11.09.2025] The crosslinker can be synthesized by the following method:

[0122] Intermediate 2 (0.166 g, 0.5 mmol), 2-hydroxymethyl-1,3-propanediol (16 mg, 0.15 mmol) in 10 mL dichloromethane, EDC (150 mg), DMAP (50 mg) were added and stirred at 25 °C for 12 h, dried by rotary evaporation, 50 mL saturated sodium chloride solution was added, extracted with dichloromethane for 3 times and dried by rotary evaporation. Purified by column chromatography, dried by rotary evaporation to give product 4 (63 g, yield 40%). 1 H NMR δ (ppm): 8.57 (3H), 7.98 (3H), 7.67 (3H), 7.54 (3H), 7.31-7.40 (6H), 4.31 (6H), 3.92 (3H), 3.40 (6H), 1.58 (9H), 1.21 (1H).

[0123] [Rule 26 correction 11.09.2025] In one example, the crosslinker reacts with the ligand as follows:

[0124] [Rule 26 correction 11.09.2025] In this example, the crosslinker is:

[0125] [Rule 26 correction 11.09.2025] The crosslinker can be synthesized by the following method:

[0126] In another embodiment of the present disclosure, the quantum dot ligand has the thiol group protected by the photolabile group; the crosslinker has a plurality of active alkenyl groups, the active alkenyl group comprising an alkenyl group and an electron-withdrawing group connected to the alkenyl group.

[0127] Optionally, the crosslinker has a first linking group, the active alkenyl group is connected to the first linking group.

[0128] The quantum dot layer using the quantum dot composition connects the quantum dot bodies to each other through the organic material. The organic material includes a ligand group coordinated with the quantum dot body and a cross-linking group connected with the plurality of ligand groups, and forms a thioether structure between the ligand group and the cross-linking group. Wherein, the cross-linking agent in the quantum dot composition forms the cross-linking group of the organic material after reacting with the mercapto group, sulfur radical or sulfur negative ion on the ligand, and the part of the ligand in the quantum dot composition for connecting the mercapto group, sulfur radical or sulfur negative ion and the quantum dot body can form the ligand group of the organic material, and the ligand group and the cross-linking group are connected through the thioether structure.

[0129] Optionally, the quantum dot ligand has a structural formula of A-B-C-D or A-B-D; wherein A is a coordination group capable of coordinating with the quantum dot body; B is a second connecting group; C is a carrier transport adjusting group; and D is the mercapto group protected by the photolysis group.

[0130] [According to Rule 26 Correction 11.09.2025] In an example, the reaction of the cross-linking agent with the ligand is as follows:

[0131] [According to Rule 26 Correction 11.09.2025] In this example, the cross-linking agent is:

[0132] [According to Rule 26 Correction 11.09.2025] In this example, the ligand is:

[0133] [According to Rule 26 Correction 11.09.2025] The ligand can be synthesized by the following method:

[0134] [According to Rule 26 Correction 11.09.2025] In another example, the reaction of the cross-linking agent with the ligand is as follows:

[0135] [According to Rule 26 Correction 11.09.2025] Wherein, the exemplary cross-linking agent can be:

[0136] [According to Rule 26 Correction 11.09.2025] In another example, the reaction of the cross-linking agent with the ligand is as follows:

[0137] [According to Rule 26 Correction 11.09.2025] Wherein, the exemplary cross-linking agent can be:

[0138] In another embodiment, the cross-linking agent has multiple thiol groups protected by the photolabile groups; the mass ratio of the ligand to the quantum dot core is no more than 30%. In this embodiment, the thiol, thiol radical or thiolate released from the cross-linking agent can directly link to the quantum dot core, thereby cross-linking the quantum dot cores.

[0139] In one example, the mass ratio of the ligand to the quantum dot core is no more than 15%.

[0140] In another example, the mass ratio of the ligand to the quantum dot core is between 15% and 30%; the acidity of the ligand is less than that of the deprotected thiol protected by the photolabile groups.

[0141] In one example, the quantum dot ligand is selected from oleic acid, oleylamine, octanethiol, dodecanethiol.

[0142] [According to Rule 26 Correction 11.09.2025] In another example, the cross-linking agent directly reacts with the quantum dot core after deprotection, and the reaction is as follows:

[0143] In one embodiment of the present disclosure, the mass content of the cross-linking agent is 1% to 5%. Of course, the amount of the cross-linking agent can also be increased or decreased as needed.

[0144] In one embodiment of the present disclosure, the quantum dot composition further includes a solvent, such as PGMEA (propylene glycol methyl ether acetate) or toluene, hexane, octane, or a combination of the above solvents. In one example, the concentration of the quantum dots is 10 to 100 mg / mL.

[0145] The cross-linking ability of the quantum dot composition under light is also verified in an embodiment of the present disclosure. Specifically, an experimental quantum dot composition containing a cross-linking agent and a control quantum dot composition not containing a cross-linking agent are provided, for example. The structures of the cross-linking agent and the ligand are as follows, respectively, and the quantum dot core is a red quantum dot core.

[0146] A layer of hole transport material capable of being excited to emit blue light under ultraviolet light is first coated on a glass substrate. Then, the control quantum dot composition is coated on the surface of the hole transport material layer and exposed and developed; after development, ultraviolet light is irradiated, as shown in FIG. 9, the surface of the glass substrate is blue. This shows that there is no red quantum dot core on the surface of the glass substrate, and the control quantum dot composition has not been cross-linked.

[0147] A layer of hole transport material capable of being excited to emit blue light under UV irradiation is first coated on a glass substrate. Then an experimental quantum dot composition is coated on the surface of the hole transport material layer and exposed and developed; after development, the glass substrate surface is irradiated with UV light, as shown in FIG. 10, the glass substrate surface is red. This shows that the red quantum dot bodies are fixed on the surface of the hole transport material layer, and the experimental quantum dot composition is cross-linked.

[0148] The present disclosure also provides a light emitting element, comprising a quantum dot layer; the quantum dot layer has quantum dot bodies connected to each other by an organic material;

[0149] The organic material comprises a ligand group coordinated with the quantum dot body and a cross-linking group connected with a plurality of ligand groups, and a sulfide structure is formed between the ligand group and the cross-linking group; or the organic material has a plurality of mercapto groups, sulfur free radicals or sulfur negative ions and is coordinated with a plurality of quantum dot bodies through mercapto groups, sulfur free radicals or sulfur negative ions.

[0150] Optionally, the quantum dot solution with the quantum dot composition provided by the embodiments of the present disclosure can be patterned by light irradiation to form a quantum dot layer of a light emitting element.

[0151] The present disclosure also provides a preparation method of a display panel, comprising: on the surface of a substrate, sequentially forming quantum dot layers of at least two sub-pixels by a photolithography process; for example, sequentially forming three quantum dot layers of red quantum dot layer, green quantum dot layer and blue quantum dot layer.

[0152] Referring to FIG. 1, forming a quantum dot layer of any one of the sub-pixels comprises:

[0153] Step S110, forming a quantum dot composition film layer on the surface of the substrate by using a quantum dot composition corresponding to the sub-pixel, the quantum dot composition is selected from the quantum dot compositions described above;

[0154] Step S120, exposing and developing the quantum dot composition film layer corresponding to the sub-pixel to obtain a quantum dot layer of the sub-pixel.

[0155] For example, when preparing a red quantum dot layer, the quantum dot body in the quantum dot composition is a red quantum dot body. When preparing a green quantum dot layer, the quantum dot body in the quantum dot composition is a green quantum dot body. When preparing a blue quantum dot layer, the quantum dot body in the quantum dot composition is a blue quantum dot body.

[0156] In an embodiment of the present disclosure, the preparation method of the display panel further comprises:

[0157] Before forming the quantum dot layer, a hole transport layer of each of the sub-pixels is formed.

[0158] In one embodiment of the present disclosure, the method for manufacturing the display panel further comprises:

[0159] After forming the quantum dot layer of each of the sub-pixels, an electron transport layer of each of the sub-pixels is formed.

[0160] In one embodiment of the present disclosure, the forming of the quantum dot composition film layer on the surface of the substrate using the quantum dot composition corresponding to the sub-pixel comprises:

[0161] The quantum dot composition film layer is formed on the surface of the substrate by a coating process using the quantum dot composition corresponding to the sub-pixel.

[0162] The method for forming multiple quantum layers is exemplarily described as follows in combination with the drawings.

[0163] In step S210, three quantum dot solutions of different colors are prepared, each of which contains quantum dot composition of a different color and a solvent.

[0164] For example, when preparing a red quantum dot solution, a red quantum dot bulk is used. When preparing a green quantum dot solution, a green quantum dot bulk is used. When preparing a blue quantum dot solution, a blue quantum dot bulk is used.

[0165] Any quantum dot solution can be prepared by the following exemplary method: a quantum dot bulk (CdSe / ZnSe quantum dot) modified with a ligand is dissolved in a solvent (e.g., n-octane or PGMEA) to form a solution with a mass concentration of 30 mg / mL. The required crosslinking agent is added to the quantum dot solution.

[0166] In step S220, the green quantum dot solution is coated on the substrate, a first mask is added, and the whole is exposed to ultraviolet light. After exposure, the PGMEA or toluene is used as a developer for rinsing and developing. After development, the substrate is heated at 90°C for 120 seconds to remove the developer, and a patterned green quantum dot layer is obtained.

[0167] In step S230, the blue quantum dot solution is coated on the substrate, a second mask is added, and the whole is exposed to ultraviolet light. After exposure, the PGMEA or toluene is used as a developer for rinsing and developing. After development, the substrate is heated at 90°C for 120 seconds to remove the developer, and a patterned blue quantum dot layer is obtained.

[0168] Step S240, coating the red quantum dot solution on the substrate, adding the third mask and exposing the whole to ultraviolet light. After exposure, PGMEA or toluene is used as a developer for rinsing and developing; after development, the substrate is heated at 90°C for 120 seconds to remove the developer, obtaining a patterned red quantum dot layer.

[0169] In steps S220-S240, the green quantum dot solution layer, the blue quantum dot solution and the red quantum dot solution can be patterned respectively by the first mask, the second mask and the third mask, and then a patterned green quantum dot layer, a patterned blue quantum dot layer and a patterned red quantum dot layer are obtained. By controlling the light transmission area of the first mask, the second mask and the third mask, the position and shape of the three different quantum dot layers can be controlled.

[0170] The preparation method of the display panel provided by the embodiment of the present disclosure will be exemplarily described as follows in combination with the accompanying drawings.

[0171] Step S310, referring to FIG. 2, a backplane BP is provided. Optionally, the backplane BP includes a substrate and a driving layer which are sequentially stacked, and the driving layer has a transistor layer and a source-drain metal layer. The various film layers of the driving layer can be prepared sequentially from the substrate, for example, a gate layer (for example, the material is molybdenum and the thickness is 200 nm), a gate insulating layer (for example, 150 nm thick silicon oxide), a semiconductor layer (for example, the material is IGZO and the thickness is 40 nm), a source-drain metal layer (for example, the material is molybdenum and the thickness is 200 nm), and a passivation layer (for example, 300 nm of silicon oxide) are sequentially prepared.

[0172] Further, a pixel electrode layer (for example, the material is ITO and the thickness is 40 nm) and a pixel definition layer PDL (for example, 1.5 microns thick acrylic) can be sequentially formed on the backplane.

[0173] Step S320, the surface of the backplane is cleaned first. For example, the surface of the backplane is treated by plasma.

[0174] Step S330, a first common material layer is prepared on the surface of the backplane, for example, a hole injection layer and a hole transport layer of each sub-pixel are prepared. In an example, the hole injection layer and the hole transport layer can be prepared by a spin coating process, for example, PEDOT:PSS (hole injection layer) and TFB (hole transport layer) are respectively spin coated. Further, the total thickness of the hole injection layer and the hole transport layer is 50-100 nm.

[0175] Step S340, referring to FIG. 3 and FIG. 4, a green quantum dot layer GQDL is prepared on the surface of the backplane BP. For example, a green quantum dot solution is coated on the backplane to form a green quantum dot composition layer G1, a first mask is added and the whole is exposed to ultraviolet light. After exposure, PGMEA or toluene is used as a developer for rinsing and developing; after development, the backplane is heated in a 90°C environment for 120 seconds to remove the developer, and a patterned green quantum dot layer GQDL is obtained.

[0176] Step S350, referring to FIG. 5 and FIG. 6, a blue quantum dot layer BQDL is prepared on the surface of the backplane BP. For example, a blue quantum dot solution is coated on the backplane to form a blue quantum dot composition layer B1, a second mask is added and the whole is exposed to ultraviolet light. After exposure, PGMEA or toluene is used as a developer for rinsing and developing; after development, the backplane is heated in a 90°C environment for 120 seconds to remove the developer, and a patterned blue quantum dot layer BQDL is obtained.

[0177] Step S360, referring to FIG. 7 and FIG. 8, a red quantum dot layer RQDL is prepared on the surface of the backplane BP. For example, a red quantum dot solution is coated on the backplane to form a red quantum dot composition layer R1, a third mask is added and the whole is exposed to ultraviolet light. After exposure, PGMEA or toluene is used as a developer for rinsing and developing; after development, the backplane is heated in a 90°C environment for 120 seconds to remove the developer, and a patterned red quantum dot layer RQDL is obtained.

[0178] Step S370, after the formation of each quantum dot layer, the preparation of a second common material layer begins. The second common material layer includes but is not limited to an electron transport layer (such as ZnO nanoparticles) and an electron injection layer. The second common material layer can be formed by spin coating or evaporation.

[0179] Step S380, a cathode is formed. For example, a thin layer of cathode metal is evaporated, and the cathode can use an Al layer, etc., about 500-1000 nm.

[0180] After evaporation, encapsulation and cutting are performed, and the preparation of the entire AMQLED display panel is completed.

[0181] In one example, the prepared display panel is a bottom light-out display panel.

[0182] In one example, the minimum size of a sub-pixel can be in the range of 10-30 microns, which makes the resolution of the display panel reach 300-800 PPI.

[0183] Optionally, in the preparation of the display panel, there can be a gap between the quantum dot layers of two adjacent sub-pixels, or the quantum dot layers of two adjacent sub-pixels can be overlapped.

[0184] In one example, the quantum dot layer is positioned within a pixel opening formed by the pixel defining layer when the display panel is fabricated.

[0185] In another example, at least a portion of an edge of the quantum dot layer is positioned outside a pixel opening formed by the pixel defining layer when the display panel is fabricated.

[0186] In some other embodiments of the present disclosure, the quantum dot body in the above-mentioned quantum dot composition can also be replaced by ZnO, ZnMgO, ZnAlO, ZnLiO, etc. nanoparticles to form an electron transport material composition, which can be used to form an electron transport layer by a photolithography process. Of course, when the electron transport layer does not need to be patterned, the film layer formed by the electron transport material composition can be cured by light irradiation.

[0187] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the present disclosure cover any and all variations of the present disclosure that come within the scope of the following claims and their equivalents. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

Claims

1. A quantum dot composition comprising a quantum dot body, a ligand, and a cross-linking agent; The ligand is coordinated and connected with the quantum dot body; in, One of the ligand and the cross-linker has a thiol group protected by a photolyzable group; The photolyzable group can be removed under light to release a sulfhydryl group, a sulfhydryl radical or a sulfhydryl anion; When the released thiol group, thiol free radical or thiol anion is located on the cross-linking agent, the released thiol group, thiol free radical or thiol anion is used to coordinate with the quantum dot body or to react with the ligand to form a chemical bond; when the released thiol group, thiol free radical or thiol anion is located on the ligand, the released thiol group, thiol free radical or thiol anion is used to react with the cross-linking agent to form a chemical bond.

2. The quantum dot composition according to claim 1, wherein The photolyzable group is selected from the following substituents: Wherein, Ar1 is selected from an aryl group having a nitro group or a hydroxyl group, or a heteroaryl group having a nitro group or a hydroxyl group; R1, R2 and R3 are each independently selected from hydrogen, deuterium, or an alkyl group having 1 to 6 carbon atoms.

3. [Corrected 11.09.2025 according to Rule 26] The quantum dot composition according to claim 2, wherein The photolyzable group is selected from the following substituents: Wherein, R5 is selected from hydrogen, deuterium, and an alkoxy group having 1 to 8 carbon atoms.

4. The quantum dot composition according to claim 1, wherein The cross-linking agent has a plurality of thiol groups protected by photolyzable groups; the ligand has an active alkenyl group, and the active alkenyl group includes an alkenyl group and an electron-withdrawing group connected to the alkenyl group.

5. The quantum dot composition according to claim 4, wherein The cross-linking agent has a first linking group, and the thiol group protected by the photolyzable group is linked to the first linking group.

6. The quantum dot composition according to claim 4, wherein The structural formula of the ligand is ABCD or ABD; wherein A is a coordination group capable of coordinating with the quantum dot; B is a second connecting group; C is a carrier transport regulating group; and D is the active alkenyl group.

7. The quantum dot composition according to claim 1, wherein The ligand has the thiol group protected by the photolyzable group; the cross-linking agent has a plurality of active alkenyl groups, and the active alkenyl groups include an alkenyl group and an electron-withdrawing group connected to the alkenyl group.

8. The quantum dot composition according to claim 7, wherein The cross-linking agent has a first linking group, and the reactive alkenyl group is linked to the first linking group.

9. The quantum dot composition according to claim 7, wherein The structural formula of the ligand is ABCD or ABD; wherein A is a coordination group capable of coordinating with the quantum dot; B is a second connecting group; C is a carrier transport regulating group; and D is the thiol protected by the photolyzable group.

10. The quantum dot composition according to claim 6 or 9, wherein The coordination group has an amino group, a carboxylic acid group, a thiol group, two thiol groups, a phosphine group or a phosphineoxy group.

11. The quantum dot composition according to claim 4 or 7, wherein The active alkenyl group is selected from the following groups: Wherein, R4 is selected from hydrogen, deuterium, and an alkyl group having 1 to 6 carbon atoms; and EWG is an electron withdrawing group.

12. The quantum dot composition according to claim 11, wherein The active alkenyl group is selected from the following groups:

13. The quantum dot composition according to claim 1, wherein The cross-linking agent has a plurality of thiol groups protected by photolyzable groups; In the quantum dot body and the ligand, the mass ratio of the ligand is no more than 30%.

14. The quantum dot composition according to claim 13, wherein In the quantum dot body and the ligand, the mass ratio of the ligand is no more than 15%.

15. The quantum dot composition according to claim 13, wherein In the quantum dot body and the ligand, the mass ratio of the ligand is between 15% and 30%; The acidity of the ligand is less than the acidity of the thiol group protected by the photolyzable group after the protecting group is removed.

16. The quantum dot composition according to claim 13, wherein The ligand is selected from oleic acid, oleylamine, octanethiol, and dodecanethiol.

17. The quantum dot composition according to any one of claims 1 to 9, wherein The mass content of the cross-linking agent is 1% to 5%.

18. A light emitting element, wherein: The light emitting element includes a quantum dot layer; the quantum dot layer has quantum dot bodies interconnected by organic materials; The organic material includes a ligand group coordinated with the quantum dot body and a cross-linking group connected to multiple ligand groups, and a thioether structure is formed between the ligand group and the cross-linking group; or, the organic material has multiple thiol groups, thiol radicals or thiol anions and is coordinated with multiple quantum dot bodies through thiol groups, thiol radicals or thiol anions.

19. A display panel, wherein: The light-emitting element according to claim 18 is included.

20. A method for preparing a display panel, comprising: On the surface of the substrate, quantum dot layers of at least two sub-pixels are formed sequentially by photolithography; Forming any one of the quantum dot layers of the sub-pixels includes: Forming a quantum dot composition film layer on the surface of the substrate using the quantum dot composition corresponding to the sub-pixel, wherein the quantum dot composition is selected from the quantum dot composition according to any one of claims 1 to 18; exposing and developing the quantum dot composition film layer corresponding to the sub-pixel to obtain the quantum dot layer of the sub-pixel; The quantum dot layers of different sub-pixels contain different quantum dots in the quantum dot compositions.

21. The method for manufacturing a display panel according to claim 20, wherein: The method for preparing the display panel further includes: Before forming the quantum dot layer, a hole transport layer is formed for each of the sub-pixels.

22. The method for manufacturing a display panel according to claim 20, wherein: The method for preparing the display panel further includes: After forming the quantum dot layer of each sub-pixel, an electron transport layer of each sub-pixel is formed.

23. The method for manufacturing a display panel according to claim 20, wherein: The step of forming a quantum dot composition film layer on the surface of the substrate using the quantum dot composition corresponding to the sub-pixels comprises: The quantum dot composition corresponding to the sub-pixel is used to form a film layer of the quantum dot composition on the surface of the substrate through a coating process.

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