Quantum dot mixed ligands, quantum dot-ligand systems, and quantum dot-ligand materials

Abstract

The present disclosure provides a quantum dot hybrid ligand, a quantum dot-ligand system, and a quantum dot-ligand material, belonging to the field of display technology. The quantum dot hybrid ligand includes a first ligand, including a first coordination group, a first linking group, and an acidic group, wherein the first linking group is connected between the first coordination group and the acidic group; a second ligand, a second coordination group, a second linking group, and a photosensitive group, wherein the second linking group is connected between the second coordination group and the photosensitive group; wherein the first coordination group and the second coordination group are used to form a coordination bond with the quantum dot body; the acidic group can undergo an acid-base reaction with an alkaline solution and ionize the first ligand; the photosensitive group is selected from a structure containing a carbon-carbon double bond, or a saturated 3-5-membered heterocyclic group containing O or S. The quantum dot hybrid ligand provides a basis for the quantum dot film layer to be formed using a photolithography process.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a quantum dot mixed ligand, a quantum dot-ligand system, and a quantum dot-ligand material. Background Art

[0002] With the advancement of quantum dot production technology, the stability and luminous efficiency of quantum dots have continued to improve, and research on quantum dot light-emitting diodes (QLEDs) has continued to deepen. The application prospects of QLEDs in the display field are becoming increasingly bright. However, the efficiency of QLEDs has not yet reached the level of mass production. One of the main reasons is that there has been no breakthrough in high-resolution patterning technology for QLEDs.

[0003] The inorganic nanoparticle characteristics of quantum dots make it impossible to form films and pattern them through evaporation; it is difficult to achieve high resolution through inkjet printing.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a quantum dot mixed ligand, a quantum dot-ligand system and a quantum dot-ligand material, wherein the quantum dot ligand provides a basis for forming a quantum dot film layer using a photolithography process.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present disclosure, there is provided a quantum dot mixed ligand, comprising:

[0008] A first ligand comprising a first coordinating group, a first connecting group and an acidic group, wherein the first connecting group is connected between the first coordinating group and the acidic group;

[0009] A second ligand, a second coordination group, a second linking group and a photosensitive group, wherein the second linking group is connected between the second coordination group and the photosensitive group;

[0010] Wherein, the first coordination group and the second coordination group are used to form a coordination bond with the quantum dot body;

[0011] The acidic group can react with the alkaline solution to produce an acid-base reaction and ionize the first ligand;

[0012] The photosensitive group is selected from a structure containing a carbon-carbon double bond, or a saturated 3-5 membered heterocyclic group containing O or S.

[0013] In an exemplary embodiment of the present disclosure, the acidic group is selected from a carboxylic acid group or a sulfonic acid group.

[0014] In an exemplary embodiment of the present disclosure, the first coordinating group and the second coordinating group are each independently selected from an amino group, a carboxylic acid group, a thiol group, a phosphine group, a phosphineoxy group or a bisthiol group.

[0015] In an exemplary embodiment of the present disclosure, the first linking group is selected from an alkylene group having 1 to 6 carbon atoms, and the second linking group is selected from an alkylene group having 2 to 12 carbon atoms.

[0016] In an exemplary embodiment of the present disclosure, the first ligand has a structure as shown in Formula I;

[0017]

[0018] Wherein, R1 is a first coordination group selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0019] R2 is an acidic group selected from a carboxylic acid group or a sulfonic acid group;

[0020] n1 is any integer selected from 0-5.

[0021] In an exemplary embodiment of the present disclosure, the photosensitive group is selected from the group consisting of the following structures:

[0022]

[0023] Wherein, R3 is selected from an alkyl group having 1 to 4 carbon atoms.

[0024] In an exemplary embodiment of the present disclosure, the second ligand further comprises:

[0025] The solubilizing group is connected between the second connecting group and the photosensitive group, and the solubilizing group is selected from polar groups.

[0026] In an exemplary embodiment of the present disclosure, the solubilizing group is selected from the group comprising structure.

[0027] In an exemplary embodiment of the present disclosure, the second ligand is selected from the group consisting of the following structures:

[0028]

[0029] wherein R4 is selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0030] n2 is any integer selected from 2 to 8;

[0031] n3 is selected from any integer between 2 and 8.

[0032] In an exemplary embodiment of the present disclosure, the quantum dot mixed ligand further comprises:

[0033] A third ligand having a structure as shown in Formula II;

[0034]

[0035] wherein R5 is selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0036] R6 is selected from polar groups;

[0037] n5 is selected from any integer between 1 and 100.

[0038] In an exemplary embodiment of the present disclosure, R6 is selected from a carboxylic acid group or a sulfonic acid group.

[0039] In an exemplary embodiment of the present disclosure, when the quantum dot mixed ligand comprises the first ligand and the second ligand, the quantum dot mixed ligand comprises 10%-50% of the first ligand and 50%-90% of the second ligand by weight percentage;

[0040] When the quantum dot mixed ligand comprises the first ligand, the second ligand and the third ligand, the quantum dot mixed ligand comprises 10%-30% of the first ligand, 40%-50% of the second ligand and 10%-30% of the third ligand by weight.

[0041] In an exemplary embodiment of the present disclosure, when the quantum dot mixed ligand comprises the first ligand and the second ligand, the first ligand and the second ligand account for 100% of the quantum dot mixed ligand;

[0042] When the quantum dot mixed ligand comprises the first ligand, the second ligand and the third ligand, the first ligand, the second ligand and the third ligand account for 100% of the quantum dot mixed ligand.

[0043] According to a first aspect of the present disclosure, a quantum dot-ligand system is provided, comprising a quantum dot body, a photoinitiator, and the quantum dot mixed ligand as described in the first aspect.

[0044] In an exemplary embodiment of the present disclosure, the photoinitiator accounts for 1%-5% of the weight of the quantum dot body in terms of weight percentage.

[0045] In an exemplary embodiment of the present disclosure, when the photosensitive group is selected from a structure containing a carbon-carbon double bond, the photosensitive initiator is selected from a photosensitive free radical initiator, and the photosensitive free radical initiator is selected from benzoin and its derivatives, acetophenone derivatives or aromatic ketone derivatives.

[0046] In an exemplary embodiment of the present disclosure, when the photosensitive group is selected from a structure containing a saturated 3-5 membered heterocyclic group containing O or S, the photoinitiator is selected from a photoacid generator, and the photoacid generator is selected from sulfonium salts, triazines, sulfonates or diazonium salts.

[0047] According to a third aspect of the present disclosure, there is provided a quantum dot-ligand material comprising a first quantum dot body, a second quantum dot body and a quantum dot mixed ligand according to any one of claims 1 to 13;

[0048] Wherein, the second ligand is connected to the first quantum dot body and the second quantum dot body respectively through coordination bonds;

[0049] The first quantum dot body and the second quantum dot body are cross-linked through the photosensitive group in the second ligand to form a network structure.

[0050] According to a fourth aspect of the present disclosure, a method for preparing a quantum dot pattern is provided, comprising:

[0051] Providing a quantum dot-ligand mixed solution, wherein the quantum dot-ligand solution is a mixed solution comprising a quantum dot body, a photosensitive initiator and the quantum dot mixed ligand as described in the first aspect;

[0052] The quantum dot-ligand mixed solution is coated on a substrate and subjected to an exposure treatment, so that the photoinitiator generates free radicals and crosslinks the carbon-carbon double bonds in the photosensitive groups; or the photoinitiator generates hydrogen ions and causes the saturated 3-5-membered heterocyclic group containing O or S in the photosensitive groups to open and crosslink;

[0053] A development process is performed to form the quantum dot pattern.

[0054] According to a fifth aspect of the present disclosure, a quantum dot light-emitting device is provided, comprising a functional layer, wherein the functional layer comprises a quantum dot film layer, and the quantum dot film layer comprises the quantum dot-ligand material as described in the third aspect.

[0055] In an exemplary embodiment of the present disclosure, the quantum dot light-emitting device further includes an anode and a cathode, and the functional layer is located between the anode and the cathode.

[0056] In an exemplary embodiment of the present disclosure, the quantum dot light-emitting device further includes a light-emitting unit, and the quantum dot film layer is provided on one side of the light-emitting unit.

[0057] According to a sixth aspect of the present disclosure, a method for preparing a quantum dot light-emitting device is provided, comprising:

[0058] Providing a first color quantum dot-ligand mixed solution, wherein the first color quantum dot-ligand mixed solution is a mixed solution comprising a first color quantum dot body, a photosensitive initiator, and the quantum dot mixed ligand according to any one of the first aspects;

[0059] Providing a second color quantum dot-ligand mixed solution, wherein the second color quantum dot-ligand solution is a mixed solution comprising a second color quantum dot body, a photosensitive initiator, and the quantum dot mixed ligand as described in the first aspect;

[0060] Coating the first color quantum dot-ligand mixed solution on the substrate, exposing and developing the solution to form first color sub-pixels;

[0061] The second color quantum dot-ligand mixed solution is coated on the substrate, and exposed and developed to form second color sub-pixels.

[0062] According to a seventh aspect of the present disclosure, a display device is provided, comprising the quantum dot light-emitting device as described in the fifth aspect.

[0063] The quantum dot mixed ligands provided by the present disclosure have a first ligand capable of undergoing an acid-base reaction with an alkaline solution, ionizing the first ligand; and a second ligand capable of undergoing a cross-linking reaction with the assistance of a photoinitiator. The first ligand and the second ligand can be combined with the quantum dot body to form a quantum dot-ligand unit. When the second ligand contained in the quantum dot-ligand unit undergoes a cross-linking reaction, its solubility is low, providing a basis for forming a quantum dot film layer using a photolithography process. When the second ligand contained in the quantum dot-ligand unit does not undergo a cross-linking reaction, its solubility is high, and the first ligand contained in the quantum dot-ligand unit helps enhance its solubility during the development process. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The above and other features and advantages of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

[0065] Figure 1 Schematic diagram of the structure of coating a first color-quantum dot ligand solution on a substrate in an exemplary embodiment of the present disclosure;

[0066] Figure 2 is a schematic diagram of a structure for forming a first color sub-pixel in an exemplary embodiment of the present disclosure;

[0067] Figure 3 Schematic diagram of the structure of coating a second color-quantum dot ligand solution on a substrate in an exemplary embodiment of the present disclosure;

[0068] Figure 4 is a schematic diagram of a structure for forming a second color sub-pixel in an exemplary embodiment of the present disclosure;

[0069] Figure 5 Schematic diagram of the structure of coating a third color-quantum dot ligand solution on a substrate in an exemplary embodiment of the present disclosure;

[0070] Figure 6 is a schematic diagram of a structure for forming a third color sub-pixel in an exemplary embodiment of the present disclosure;

[0071] Figure 7 is a schematic structural diagram of a quantum dot light-emitting device in an exemplary embodiment of the present disclosure;

[0072] Figure 8 It is a schematic structural diagram of a quantum dot light-emitting device in another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0073] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in many 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 more comprehensive and complete and will fully convey the concepts of the 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 provide a thorough understanding of the embodiments of the present disclosure.

[0074] In the drawings, the thickness of regions and layers may be exaggerated for clarity. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed description will be omitted.

[0075] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, components, materials, etc. can be adopted. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring the main technical ideas of the present disclosure.

[0076] When a structure is “on” another structure, it may mean that the structure is integrally formed on 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.

[0077] The terms "a," "an," and "the" are used to indicate the presence of one or more elements / components; the terms "including" and "having" are used to indicate an open-ended inclusiveness and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc. The terms "first," "second," etc. are used merely as labels and do not limit the quantity of the items to which they refer.

[0078] Quantum dots (QD) are composed of atoms such as zinc, cadmium, selenium and sulfur. They are nanomaterials with crystal diameters between 2-10nm. They have unique photoelectric properties. After being photoelectrically stimulated, they will emit pure monochromatic light of various colors depending on the diameter of the quantum dots, and can change the color of the light source.

[0079] Quantum dots are typically used to form the quantum dot film layer of quantum dot light-emitting devices. Quantum dot light-emitting devices typically consist of an anode, a hole transport layer, a quantum dot film layer, an electron transport layer, and a cathode, stacked in sequence. When a voltage is applied to the cathode and anode, an electric field is generated between the two electrodes. Under the influence of this electric field, electrons on the cathode side migrate toward the quantum dot film layer, and holes on the anode side also migrate toward the light-emitting layer. The electrons and holes combine in the quantum dot film layer to form excitons. The excitons, in an excited state, release energy outward, causing the quantum dot film layer to emit light.

[0080] Quantum dots, due to their vulnerability to heat and moisture, cannot be deposited using the same vapor deposition method as self-luminous OLEDs and can only be produced using inkjet printing. However, achieving high resolution through inkjet printing is difficult.

[0081] The present disclosure provides a quantum dot hybrid ligand and a method for preparing a quantum dot film layer using the quantum dot hybrid ligand. The quantum dot hybrid ligand has good solubility and photosensitivity. When preparing the quantum dot film layer, red, green, and blue sub-pixels are directly formed through a photolithography process, avoiding the technical difficulties of improving resolution similar to inkjet printing, such as the need for a higher-precision printhead. The quantum dot hybrid ligand provided by the present disclosure facilitates the production of high-resolution QLED products, facilitates process preparation, improves process yield, and can significantly increase the utilization rate of quantum dot materials, thereby providing a foundation for the large-scale industrialization of QLEDs.

[0082] The present disclosure provides a quantum dot mixed ligand, comprising:

[0083] The first ligand comprises a first coordination group, a first linking group and an acidic group, wherein the first linking group is connected between the first coordination group and the acidic group;

[0084] A second ligand, a second coordination group, a second linking group and a photosensitive group, wherein the second linking group is connected between the second coordination group and the photosensitive group;

[0085] Wherein, the first coordination group and the second coordination group are used to form a coordination bond with the quantum dot body;

[0086] The acidic group can undergo an acid-base reaction with the alkaline solution and ionize the first ligand;

[0087] The photosensitive group is selected from a structure containing a carbon-carbon double bond, or a saturated 3-5 membered heterocyclic group containing O or S.

[0088] The quantum dot mixed ligands provided by the present disclosure have a first ligand capable of undergoing an acid-base reaction with an alkaline solution, ionizing the first ligand; and a second ligand capable of undergoing a cross-linking reaction with the assistance of a photoinitiator. The first ligand and the second ligand can be combined with the quantum dot body to form a quantum dot-ligand unit. When the second ligand contained in the quantum dot-ligand unit undergoes a cross-linking reaction, its solubility is low, providing a basis for forming a quantum dot film layer using a photolithography process. When the second ligand contained in the quantum dot-ligand unit does not undergo a cross-linking reaction, its solubility is high, and the first ligand contained in the quantum dot-ligand unit helps enhance its solubility during the development process.

[0089] Quantum dots (QDs) are inorganic semiconductor nanoparticles synthesized via a solution method and are sized between 1 and 10 nm, which is approximately or smaller than the particle's exciton Bohr radius. Due to their small size and large specific surface area, quantum dots are prone to agglomeration, and they also have numerous surface defects. Therefore, when used, the surface of quantum dots is often coated with organic surface ligands, which provide both protection and improved solubility in solution. The migration of charge carriers (electrons and holes) within quantum dots is confined to the interior of the quantum dots, giving them unique optical and electrical properties. Due to their unique size-dependent properties, the absorption and luminescence properties of quantum dots can be easily tuned by controlling the particle size, shape, or surface structure.

[0090] The quantum dot bodies of the present disclosure may be semiconductor nanocrystals and may have various shapes, such as spherical, conical, multi-armed and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. Here, the quantum rods may be quantum dot bodies having an aspect ratio (length to diameter ratio) (length: width ratio) 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 rods 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.

[0091] The quantum dot bodies can have a particle diameter (average maximum particle length for non-spherical shapes), for example, from about 1 nm to about 100 nm, from about 1 nm to about 80 nm, from about 1 nm to about 50 nm, or from about 1 nm to 20 nm.

[0092] 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 emission wavelength can be controlled. For example, when the size of the quantum dot body increases, 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 decreases, 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 in 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, a third color light, or a first color light, the second color light may have, for example, a peak emission wavelength (λ maximum) in the range of about 430 nm to about 480 nm, the third color light may have, for example, a peak emission wavelength (λ maximum) in the range of about 600 nm to about 650 nm, and the first color light may have, for example, a peak emission wavelength (λ maximum) in the range of about 520 nm to about 560 nm, but is not limited thereto.

[0093] For example, the average particle size of the quantum dot bodies configured to emit light of the second color can be, for example, less than or equal to about 4.5 nm, and, for example, 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 a range, for example, the average particle size of the quantum dot bodies can be from about 2.0 nm to about 4.5 nm, such as from about 2.0 nm to about 4.3 nm, from about 2.0 nm to about 4.2 nm, from about 2.0 nm to about 4.1 nm, or from about 2.0 nm to about 4.0 nm.

[0094] 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%.

[0095] The quantum dot body can have a relatively narrow full width at half maximum (FWHM). Here, FWHM is the width corresponding to half the wavelength of the peak absorption point. When the FWHM is narrow, it can be configured to emit light in a narrow wavelength region and obtain higher color purity. The quantum dot body may have a FWHM of, for example, 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. Within a range, it can have a FWHM of, for example, 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.

[0096] For example, the quantum dot body may include 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. The II-VI semiconductor compound may be, for example, selected from: a binary compound such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or a mixture thereof; a ternary compound such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnT e, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but are not limited thereto. The III-V semiconductor compounds may be selected, for example, from binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNPs, GaNAs, GaNSb, GaPAs, GaPSb, AlNPs, AlNAs, AlNSb, AlPAs, AlPSb, InNPs, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNPs, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNPs, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNPs, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but are not limited thereto. The IV-VI semiconductor compounds may be selected, for example, 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.Group IV semiconductors may be selected from, for example, elemental (mono) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. Group I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but are not limited thereto. Group I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS, or mixtures thereof, but are not limited thereto. Group II-III-V semiconductor compounds may include, for example, InZnP, but are not limited thereto.

[0097] The quantum dot body may include a single semiconductor, a binary semiconductor compound, a ternary semiconductor compound, or a quaternary semiconductor compound in a substantially uniform concentration or with locally varying concentration distributions.

[0098] For example, the quantum dot body may 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 issues and is a restricted element in many countries under the Restriction of Hazardous Substances (RoHS) directive, and therefore a non-cadmium-based quantum dot body can be effectively used.

[0099] 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 less than or equal to approximately 480 nm, for example, from approximately 430 nm to approximately 480 nm, and may be configured to emit light of a second color.

[0100] 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.

[0101] In the compound, a molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. The semiconductor compound may have a peak emission wavelength (λ max ) in a wavelength region less than about 700 nm, for example, about 600 nm to about 650 nm, and may be configured to emit a third color light.

[0102] The quantum dot body may have a core-shell structure, wherein one quantum dot body surrounds another quantum dot body. For example, the core and shell of the quantum dot body may have an interface, and an element of at least one of the core or shell at the interface may have a concentration gradient, wherein the concentration of the shell element decreases toward the core. For example, the material composition of the shell of the quantum dot body has a higher energy band gap than the material composition of the core of the quantum dot body, and thus the quantum dot body may exhibit a quantum confinement effect.

[0103] 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 a single composition, an alloy, and / or have a concentration gradient.

[0104] For example, a shell of a multi-layer shell farther from the core may have a higher energy band gap than a shell closer to the core, and thus the quantum dot body may exhibit a quantum confinement effect.

[0105] For example, a quantum dot body having a core-shell structure may, for example, include: a core, the core including a first semiconductor compound, the first semiconductor compound including 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 the composition of the core.

[0106] For example, the first semiconductor compound may 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 ZnTexSe1-x, where x is greater than approximately 0 and less than or equal to 0.05.

[0107] For example, in a first semiconductor compound based on Zn-Te-Se, the molar amount of zinc (Zn) may be higher than the molar amount of selenium (Se), and the molar amount of selenium (Se) may 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) 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 0.02 9. 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) may 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.

[0108] The second semiconductor compound may include, for example, a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a Group 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. 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.

[0109] For example, the second semiconductor compound may include zinc (Zn), selenium (Se), and / or sulfur (S). For example, the shell may include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed proximate the core and an outermost shell disposed at the outermost side of the quantum dot body. The inner shell may include ZnSeS, ZnSe, or a combination thereof, and the outermost shell may include ZnS. For example, the shell may have a concentration gradient of one component, and, for example, the amount of sulfur (S) may increase as one moves away from the core.

[0110] For example, a quantum dot body having a core-shell structure may include: a core, the core including a third semiconductor compound, the 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 composition different from that of the core.

[0111] In the third semiconductor compound based on In-Zn-P, a molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. For example, in the third semiconductor compound based on In-Zn-P, the molar ratio of zinc (Zn) to indium (In) 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, in the third semiconductor compound based on In-Zn-P, the molar ratio of zinc (Zn) to indium (In) may 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.

[0112] The fourth semiconductor compound may include, for example, a II-VI semiconductor compound, a III-V semiconductor compound, a IV-VI semiconductor compound, a Group 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. 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.

[0113] For example, the fourth semiconductor compound may include zinc (Zn) and sulfur (S), and optionally selenium (Se). For example, the shell may include ZnSeS, ZnSe, ZnS, or a combination thereof. For example, the shell may include at least one inner shell disposed proximate the core and an outermost shell disposed at the outermost side of the quantum dot body. At least one of the inner shell and the outermost shell may include the fourth semiconductor compound ZnS, ZnSe, or ZnSeS.

[0114] In the present disclosure, the first ligand and the second ligand in the quantum dot mixed ligand can form coordination bonds with the surface of the quantum dot body through their respective coordination groups, thereby connecting the first ligand and the second ligand to the surface of the quantum dot body.

[0115] The acidic group is selected from a carboxylic acid group or a sulfonic acid group. The carboxylic acid group or the sulfonic acid group can react with an alkaline solution such as TMAH (tetramethylammonium hydroxide) to ionize, thereby increasing its solubility in aqueous solution. For example, the carboxylic acid group -COOH can be ionized to Sulfonic acid group -SO3H can be ionized to

[0116] The first coordinating group is selected from an amino group, a carboxylic acid group, a thiol group, a phosphino group, a phosphinooxy group or a bisthiol group. Among them, the bisthiol group can be formed by a saturated five-membered ring or six-membered ring containing a disulfide bond. For example, when the first coordinating group is selected from a thiol group, the S atom in the thiol group forms a coordination bond with the surface of the ZnSe / CdSe quantum dot body. When the first coordinating group is selected from an amino group, the N atom in the amino group forms a coordination bond with the surface of the ZnSe / CdSe quantum dot body. When the first coordinating group is selected from a bisthiol group, the disulfide bond is broken and the S atom therein forms a coordination bond with the surface of the ZnSe / CdSe quantum dot.

[0117] In one embodiment, the first coordinating group is selected from a thiol group or a dithiol group, and the acidic group is selected from a carboxylic acid group.

[0118] Bisthiols can be Formed as The structure shown.

[0119] The first linking group is selected from an alkylene group having 1 to 6 carbon atoms. The alkylene group may have 1, 2, 3, 4, 5, or 6 carbon atoms. The alkylene group may be a linear or branched alkylene group, such as a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, a pentylene group, a hexylene group, and the like.

[0120] In some embodiments of the present disclosure, the first ligand has a structure as shown in Formula I;

[0121]

[0122] Wherein, R1 is a first coordination group selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0123] R2 is an acidic group selected from a carboxylic acid group or a sulfonic acid group;

[0124] n1 is any integer selected from 0-5, specifically 0, 1, 2, 3, 4 or 5.

[0125] Preferably, the first ligand has the following structure: n1 is any integer selected from 0-5.

[0126] This structure can be ionized in alkaline solution to Among them, the thiol group can form a coordination bond with the quantum dot body.

[0127] The photosensitive group is selected from a structure containing a carbon-carbon double bond, or a saturated 3-5 membered heterocyclic group containing O or S. The 3-5 membered heterocyclic group can be a three-membered ring, a four-membered ring or a five-membered ring.

[0128] Preferably, the photosensitive group is selected from a structure containing a carbon-carbon double bond or an epoxy group.

[0129] The photosensitive group is selected from the group consisting of the following structures:

[0130]

[0131] Wherein, R3 is selected from an alkyl group having 1 to 4 carbon atoms, and specifically an alkyl group having 1, 2, 3 or 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

[0132] Photosensitive groups can be Connect with other groups.

[0133] The second coordination group is selected from amino, carboxylic acid, sulfhydryl, phosphino, phosphinooxy or dithiol. Dithiol can be

[0134] The second linking group is selected from an alkylene group having 2 to 12 carbon atoms. Specifically, the alkylene group may have 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms. The alkylene group may be a linear alkylene group or a branched alkylene group, such as ethylene, n-propylene, isopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, pentylene, hexylene, heptylene, and octylene, but is not limited thereto.

[0135] In some embodiments of the present disclosure, the second ligand further includes: a solubilizing group connected between the second connecting group and the photosensitive group, and the solubilizing group is selected from polar groups.

[0136] The solubilizing group is selected from polar groups. Polar groups refer to groups whose positive and negative charge centers do not overlap. The polarity of such groups can be characterized by dipole moment. The dipole moment is the product of the distance l between the positive and negative charge centers and the charge ±q carried by the charge center. It is a vector whose direction is defined as pointing from the positive center to the negative center. It is represented by the symbol μ, μ=ql, and the polar group dipole moment μ>0.5. That is, the dipole moment μ of the solubilizing group is>0.5. The polar group shows affinity for polar solvents such as propylene glycol methyl ether acetate (PGMEA), and determines the hydrophilic properties of the quantum dot ligand disclosed herein.

[0137] Furthermore, the solubilizing group may be a strongly polar group, ie a group with μ>0.7.

[0138] In some embodiments of the present disclosure, the solubilizing group is selected from the group consisting of structure. etc., L is selected from 1-3 alkylene groups.

[0139] The second ligand is selected from the group consisting of:

[0140]

[0141] wherein R4 is selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0142] n2 is any integer selected from 2 to 8;

[0143] n3 is selected from any integer between 2 and 8.

[0144] n2 and n3 can be specifically selected from 2, 3, 4, 5, 6, 7 or 8.

[0145] Furthermore, the second ligand is selected from the group consisting of the following structures:

[0146]

[0147] Wherein, n4 is selected from any integer between 2 and 4, and specifically can be 2, 3 or 4.

[0148] In some embodiments of the present disclosure, the quantum dot mixed ligand further comprises:

[0149] A third ligand having a structure as shown in Formula II;

[0150]

[0151] wherein R5 is selected from amino, carboxylic acid, thiol, phosphino, phosphinooxy or dithiol;

[0152] R6 is selected from polar groups;

[0153] n5 is any integer selected from 1 to 100. Specifically, n5 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100, but is not limited thereto.

[0154] In the present disclosure, the third ligand contains a PEG (polyethylene glycol) segment structure, which makes the third ligand more soluble in PGMEA (propylene glycol methyl ether acetate), TMAH (tetramethyl ammonium hydroxide) or other aqueous solutions. TMAH (tetramethyl ammonium hydroxide) and PGMEA (propylene glycol methyl ether acetate) are commonly used solvents in the photolithography process of display devices. In the actual process, PGMEA can be used to spin-coat or scrape a mixed solution of quantum dot bodies and quantum dot mixed ligands into a film, and developed using a TMAH alkaline aqueous solution. The first ligand and the third ligand provide convenience for the development and cleaning steps in the photolithography process.

[0155] In some embodiments of the present disclosure, R6 is selected from a carboxylic acid group or a sulfonic acid group.

[0156] The third ligand is selected from the following structures:

[0157]

[0158] As above, n5 is any integer selected from 1-100.

[0159] In the present disclosure, the mixing ratios of the various ligands in the quantum dot mixed ligands are different, and the solubility of the material formed by the different ratios of ligands combined with the quantum dot body is different.

[0160] In some embodiments of the present disclosure, when the quantum dot mixed ligand includes a first ligand and a second ligand, the quantum dot mixed ligand includes 10%-50% of the first ligand and 50%-90% of the second ligand by weight. Specifically, the proportion of the first ligand can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc., and the proportion of the second ligand can be 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, etc., but are not limited thereto. Further, the first ligand and the second ligand account for 100% of the weight of the quantum dot mixed ligand.

[0161] When the quantum dot mixed ligand comprises a first ligand, a second ligand, and a third ligand, the quantum dot mixed ligand comprises, by weight percentage, 10%-30% of the first ligand, 40%-60% of the second ligand, and 10%-30% of the third ligand. Specifically, the proportion of the first ligand can be 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, etc., the proportion of the second ligand can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, etc., and the proportion of the third ligand can be 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, etc., but is not limited thereto. Furthermore, the first ligand, the second ligand and the third ligand account for 100% of the weight of the quantum dot mixed ligands.

[0162] In the present disclosure, each ligand occupies a different proportion in the mixed ligand. Within this proportion range, on the one hand, it can effectively ensure that the quantum dot-ligand unit has sufficiently good solubility when no cross-linking occurs, and the quantum dot-ligand unit can be dissolved in solutions such as PGMEA and TMAH, providing a basis for spin coating of the solution in the photolithography process and removal of residues in the subsequent development process; on the other hand, it can also greatly reduce the solubility of the quantum dot-ligand unit after the cross-linking reaction occurs, and it cannot be dissolved in solutions such as PGMEA and TMAH, thereby providing the possibility of forming a quantum dot film layer using a photolithography process.

[0163] The present disclosure also provides a quantum dot-ligand system, comprising a quantum dot body, a photoinitiator and the quantum dot mixed ligand as described above.

[0164] In terms of weight percentage, the photoinitiator accounts for 1% to 5% of the weight of the quantum dot body, and can be specifically 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, but is not limited thereto.

[0165] In the present disclosure, the ratio of the photoinitiator in the quantum dot-ligand system is required to complete crosslinking under the smallest possible light dose, such as ultraviolet light UV dose, and the added amount should not be too much to avoid affecting the device performance.

[0166] When the photosensitive group is selected from a structure containing a carbon-carbon double bond, the photoinitiator is selected from a photosensitive free radical initiator, and the photosensitive free radical initiator is selected from benzoin and its derivatives, acetophenone derivatives, or aromatic ketone derivatives. Under light conditions, the photoinitiator generates free radicals that can promote crosslinking of the carbon-carbon double bond in the photosensitive group.

[0167] When the photosensitive group is selected from a structure containing a saturated 3-5-membered heterocyclic group containing O or S, the photoinitiator is selected from a photoacid generator, and the photoacid generator is selected from sulfonium salts, triazines, sulfonates, or diazonium salts. Under light conditions, the photoinitiator generates hydrogen ions, which promote the ring-opening and crosslinking of the saturated 3-5-membered heterocyclic group containing O or S in the photosensitive group.

[0168] The present disclosure also provides a quantum dot-ligand material, comprising a first quantum dot body, a second quantum dot body and the quantum dot mixed ligand as described above;

[0169] The second ligand is connected to the first quantum dot body and the second quantum dot body respectively through coordination bonds;

[0170] The first quantum dot body and the second quantum dot body are cross-linked through the photosensitive group in the second ligand to form a network structure. Specifically, the network structure is formed by cross-linking the carbon-carbon double bonds in the photosensitive group, or by ring-opening cross-linking of a saturated 3-5 membered heterocyclic group containing O or S in the photosensitive group. The materials of the first quantum dot body and the second quantum dot body can be the same or different. For example, both can be cadmium-containing quantum dot bodies, both can be cadmium-free quantum dot bodies, or the first quantum dot body can be a cadmium-containing quantum dot body, while the second quantum dot body can be a cadmium-free quantum dot body.

[0171] The present disclosure also provides a method for preparing a quantum dot pattern, comprising:

[0172] Step S100, providing a quantum dot-ligand mixed solution, wherein the quantum dot-ligand solution is a mixed solution comprising quantum dot bodies, a photoinitiator and the quantum dot mixed ligand as described above;

[0173] Step S200, coating a quantum dot-ligand mixed solution on a substrate and performing an exposure treatment, so that the photoinitiator generates free radicals and crosslinks the carbon-carbon double bonds in the photosensitive groups; or the photoinitiator generates hydrogen ions and ring-opens and crosslinks the saturated 3-5-membered heterocyclic groups containing O or S in the photosensitive groups;

[0174] Step S300 , performing development processing to form a quantum dot pattern.

[0175] The present disclosure also provides a quantum dot light-emitting device including a functional layer, the functional layer including a quantum dot film layer, and the quantum dot film layer including the quantum dot-ligand material as described above.

[0176] The quantum dot light-emitting device provided by the present disclosure may be an electro-induced quantum dot light-emitting device or a photo-induced quantum dot light-emitting device.

[0177] In some embodiments of the present disclosure, the quantum dot light-emitting device further includes an anode and a cathode, and the functional layer is disposed between the anode and the cathode. The functional layer further includes a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0178] like Figure 7 As shown, in a specific embodiment of the present disclosure, the quantum dot light-emitting device may include a substrate 11 and a first electrode 131, a hole injection layer 133d, a hole transport layer 133b, a quantum dot film layer 133a, an electron transport layer 133c, an electron injection layer 133e and a second electrode 132 stacked in sequence on one side of the substrate 11.

[0179] The substrate 11 may be a member that provides a base surface on which the display device layer DP-OEL is disposed. The substrate 11 may be an inorganic material such as a glass substrate or a metal substrate; an organic material such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyethersulfone, or a combination thereof; a silicon wafer; or a composite material layer.

[0180] One of the first electrode 131 and the second electrode 132 is an anode and the other is a cathode. For example, the first electrode 131 may be an anode and the second electrode 132 may be a cathode. For example, the first electrode 131 may be a cathode and the second electrode 132 may be an anode.

[0181] The anode may include a conductor having a high work function, such as a metal, a conductive metal oxide, or a combination thereof. The anode may include, for example, nickel, platinum, vanadium, chromium, copper, zinc, or gold, or an alloy thereof; the conductive metal oxide may include zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide; or the combination of the metal and the conductive metal oxide may include ZnO and Al, or SnO2 and Sb, but is not limited thereto.

[0182] The cathode may include a conductor having a lower work function than the anode, such as a metal, a conductive metal oxide, and / or a conductive polymer. The cathode may include, for example, a metal such as aluminum, magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, silver, tin, lead, cesium, barium, or an alloy thereof; a multilayer structure such as LiF / Al, Li2O / Al, Liq / Al, LiF / Ca, and BaF2 / Ca, but is not limited thereto.

[0183] The work function of the anode may be higher than the work function of the cathode, for example, the work function of the anode may be, for example, about 4.5 eV to about 5.0 eV, and the work function of the cathode may be, for example, about 4.0 eV to about 4.7 eV. Within this range, the work function of the anode may be, for example, about 4.6 eV to about 4.9 eV or about 4.6 eV to about 4.8 eV, and the work function of the cathode may be, for example, about 4.0 eV to about 4.6 eV or about 4.3 eV to about 4.6 eV.

[0184] The first electrode 131 and the second electrode 132 can be transmissive electrodes, partially transmissive and partially reflective electrodes, or reflective electrodes. The transmissive electrodes or partially transmissive and partially reflective electrodes can include conductive oxides such as zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), or fluorine-doped tin oxide, or metal thin layers. The reflective electrodes can include reflective metals, such as opaque conductors such as aluminum (Al), silver (Ag), or gold (Au). The first and second electrodes can be single-layer or multi-layer structures.

[0185] At least one of the first electrode 131 or the second electrode 132 may be connected to the auxiliary electrode. If connected to the auxiliary electrode, the resistance of the second electrode 132 may be reduced.

[0186] The hole transport layer 133b and the hole injection layer 133d are disposed between the first electrode 131 and the quantum dot film layer 133a. The hole transport layer 133b is disposed between the first electrode 131 and the quantum dot film layer 133a, near the quantum dot film layer 133a, and the hole injection layer 133d is disposed between the first electrode 131 and the quantum dot film layer 133a, near the first electrode 131. The hole injection layer 133d can facilitate the injection of holes from the first electrode, and the hole transport layer 133b can effectively transfer the injected holes to the quantum dot film layer 133a. The hole transport layer 133b and the hole injection layer 133d can each have one, two, or more layers, and in a broad sense, can include an electron blocking layer.

[0187] The hole transport layer 133b and the hole injection layer 133d may each have a HOMO energy level between the work function of the first electrode 131 and the HOMO energy level of the quantum dot film layer 133a. For example, the work function of the first electrode 131, the HOMO energy level of the hole injection layer 133d, the HOMO energy level of the hole transport layer 133b, and the HOMO energy level of the quantum dot film layer 133a may gradually deepen and may be, for example, stepped.

[0188] The hole transport layer 133b may have a relatively deep HOMO energy level to match the HOMO energy level of the quantum dot film layer 133a. Therefore, the mobility of holes transferred from the hole transport layer 133b to the quantum dot layer may be improved.

[0189] The HOMO energy level of the hole transport layer 133b may be equal to the HOMO energy level of the quantum dot film layer 133a or less than the HOMO energy level of the quantum dot film layer 133a in the range of about 1.0 eV or less. For example, the difference between the HOMO energy levels of the hole transport layer 133b and the quantum dot film layer 133a may be about 0 eV to about 1.0 eV, within a range, such as about 0.01 eV to about 0.8 eV, within a range, such as about 0.01 eV to about 0.7 eV, within a range, such as about 0.01 eV to about 0.5 eV, within a range, such as about 0.01 eV to about 0.4 eV, such as about 0.01 eV to about 0.3 eV, such as about 0.01 eV to about 0.2 eV, such as about 0.01 eV to about 0.1 eV.

[0190] The HOMO energy level of the hole transport layer 133b can be, for example, greater than or equal to about 5.0 eV, within a range, for example, greater than or equal to about 5.2 eV, within a range, for example, greater than or equal to about 5.4 eV, within a range, for example, greater than or equal to about 5.6 eV, within a range, for example, greater than or equal to about 5.8 eV.

[0191] For example, the HOMO energy level of the hole transport layer 133b may be about 5.0 eV to about 7.0 eV, within the above range, for example, about 5.2 eV to about 6.8 eV, within the above range, for example, about 5.4 eV to about 6.8 eV, for example, about 5.4 eV to about 6.7 eV, for example, about 5.4 eV to about 6.5 eV, for example, about 5.4 eV to about 6.3 eV, for example, about 5.4 eV to about 6.2 eV, for example, about 5.4 eV to about 6.1 eV, for example, about 5.6 eV to about 7.0 eV, for example, about 5.6 eV to about 6.8 eV , for example, about 5.6eV to about 6.7eV, for example, about 5.6eV to about 6.5eV, for example, about 5.6eV to about 6.3eV, for example, about 5.6eV to about 6.2eV, for example, about 5.6eV to about 6.1eV, for example, about 5.8eV to about 7.0eV, for example, about 5.8eV to about 6.8eV, for example, about 5.8eV to about 6.7eV, for example, about 5.8eV to about 6.5eV, for example, about 5.8eV to about 6.3eV, for example, about 5.8eV to about 6.2eV, for example, about 5.8eV to about 6.1eV.

[0192] The hole transport layer 133b and the hole injection layer 133d may include a material that satisfies the energy level without particular limitation, and may include, for example, at least one selected from the group consisting of poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB), poly(N,N'-bis-4-butylphenyl-N,N'-bisphenyl)benzidine (poly TPD), polyarylamine (polyarylamine), poly(N-vinylcarbazole), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA (4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine), 4,4',4"-tris(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), p-type metal oxides (e.g., NiO, WO3, MoO3, etc.), carbon-based materials such as graphene oxide, phthalocyanine compounds (e.g., copper phthalocyanine);N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), Poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl -4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate and / or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN), carbazole derivatives (e.g. N-phenylcarbazole and / or polyvinylcarbazole), fluorine derivatives, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD), triphenylamine derivatives (e.g. 4, 4',4"-tris(N-carbazolyl)triphenylamine (TCTA)), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-methylphenyl)amino]-3,3'-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), and combinations thereof, but are not limited thereto.

[0193] One or both of the hole transport layer and the hole injection layer may be omitted.

[0194] The hole transport layer 133b and the hole injection layer 133d may be formed using one or more suitable methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, sputtering, inkjet printing, laser printing, and / or laser induced thermal imaging (LITI) method.

[0195] Quantum dots of different sizes in the quantum dot film layer can emit light of different colors and form sub-pixels of different colors, such as the first color sub-pixel 13G, the second color sub-pixel 13B, and the third color sub-pixel 12R.

[0196] The electron transport layer 133c and the electron injection layer 133e are disposed between the second electrode 132 and the quantum dot film layer 133a. The electron transport layer 133c is disposed between the second electrode 132 and the quantum dot film layer 133a, near the quantum dot film layer 133a, and the electron injection layer 133e is disposed between the second electrode 132 and the quantum dot film layer 133a, near the second electrode 132. The electron injection layer 133e can facilitate the injection of electrons from the second electrode, and the electron transport layer 133c can efficiently transfer the injected electrons to the quantum dot film layer 133a. The electron transport layer 133c and the electron injection layer 133e can each have one or two or more layers, and can broadly include a hole blocking layer.

[0197] For example, the electron injection layer 133 e may contact the second electrode 132 .

[0198] For example, the electron transport layer 133 c may be in contact with the quantum dot film layer 133 a .

[0199] For example, the electron transport layer 133c and the electron injection layer 133e may be in contact with each other.One or both of the electron transport layer and the electron injection layer may be omitted.

[0200] For example, the LUMO energy levels of the second electrode 132, the electron injection layer 133e, the electron transport layer 133c, and the quantum dot film layer 133a may gradually become shallower. For example, the LUMO energy level of the electron injection layer 133e may be shallower than the work function of the second electrode 132, and the LUMO energy level of the electron transport layer 133c may be shallower than the LUMO energy level of the electron injection layer 133e, and the LUMO energy level of the quantum dot film layer 133a may be shallower than the LUMO energy level of the electron transport layer 133c. That is, the work function of the second electrode 132, the LUMO energy level of the electron injection layer 133e, the LUMO energy level of the electron transport layer 133c, and the LUMO energy level of the quantum dot film layer 133a may have a step-wise (cascade) energy level that gradually decreases in one direction.

[0201] The electron transport layer 133c may include first inorganic nanoparticles. The first inorganic nanoparticles may be, for example, oxide nanoparticles, and may be, for example, metal oxide nanoparticles.

[0202] The first inorganic nanoparticles may be two-dimensional or three-dimensional nanoparticles having an average particle diameter of less than or equal to about 10 nm, within a range of less than or equal to about 8 nm, less than or equal to about 7 nm, less than or equal to about 5 nm, less than or equal to about 4 nm, or less than or equal to about 3.5 nm, or within a range of about 1 nm to about 10 nm, about 1 nm to about 9 nm, about 1 nm to about 8 nm, about 1 nm to about 7 nm, about 1 nm to about 5 nm, about 1 nm to about 4 nm, or about 1 nm to about 3.5 nm.

[0203] For example, the first inorganic nanoparticles may be metal oxide nanoparticles, and the metal oxide nanoparticles include at least one of the following: zinc (Zn), magnesium (Mg), cobalt (Co), nickel (Ni), gallium (Ga), aluminum (Al), calcium (Ca), zirconium (Zr), tungsten (W), lithium (Li), titanium (Ti), tantalum (Ta), tin (Sn), hafnium (Hf), and barium (Ba).

[0204] As an example, the first inorganic nanoparticles may include metal oxide nanoparticles including zinc (Zn), and may include metal oxide nanoparticles represented by Zn1-xQxO (0≤x<0.5). Here, Q is at least one metal other than Zn, such as magnesium (Mg), cobalt (Co), nickel (Ni), gallium (Ga), aluminum (Al), calcium (Ca), zirconium (Zr), tungsten (W), lithium (Li), titanium (Ti), tantalum (Ta), tin (Sn), hafnium (Hf), silicon (Si), barium (Ba), or a combination thereof.

[0205] For example, Q may include magnesium (Mg).

[0206] For example, x may be in the range of 0.01≤x≤0.3, eg, 0.01≤x≤0.2.

[0207] The LUMO energy level of the electron transport layer 16 may be a value between the LUMO energy level of the quantum dot film layer 133a and the LUMO energy level of the electron injection layer 17, and may be about 3.2eV to about 4.8eV, about 3.2eV to about 4.6eV, about 3.2eV to about 4.5eV, about 3.2eV to about 4.3eV, about 3.2eV to about 4.1eV, about 3.4eV to 4.1eV, about 3.5eV to about 4.6eV, about 3.6eV to about 4.6eV, about 3.6eV to about 4.3eV, about 3.6eV to about 4.1eV, about 3.6eV to about 3.9eV, about 3.7eV to about 4.6eV, about 3.7eV to about 4.3eV, about 3.7eV to about 4.1eV, or about 3.7eV to about 3.9eV.

[0208] The thickness of the electron transport layer 133c may be greater than about 10 nm and less than or equal to about 80 nm, and within a range of greater than about 10 nm and less than or equal to about 70 nm, greater than about 10 nm and less than or equal to about 60 nm, greater than about 10 nm and less than or equal to about 50 nm, greater than about 10 nm and less than or equal to about 40 nm, or greater than about 10 nm and less than or equal to about 30 nm.

[0209] The LUMO energy level of the electron injection layer 133e may be between the work function of the second electrode 132 and the LUMO energy level of the electron transport layer. For example, the difference between the work function of the second electrode 132 and the LUMO energy level of the electron injection layer 133e may be less than about 0.5 eV, about 0.001 eV to about 0.5 eV, about 0.001 eV to about 0.4 eV, or about 0.001 eV to about 0.3 eV. As an example, the difference between the LUMO energy level of the electron injection layer 133e and the LUMO energy level of the electron transport layer may be less than about 0.5 eV, about 0.001 eV to about 0.5 eV, about 0.001 eV to about 0.4 eV, or about 0.001 eV to about 0.3 eV. Therefore, electrons can be easily injected from the second electrode 132 into the electron injection layer 133e to reduce the driving voltage of the quantum dot device, and electrons can be efficiently transferred from the electron injection layer 133e to the electron transport layer to improve efficiency. Within the range satisfying the aforementioned energy levels, the LUMO energy level of the electron injection layer may be about 3.4eV to about 4.8eV, about 3.4eV to about 4.6eV, about 3.4eV to about 4.5eV, about 3.6eV to about 4.8eV, about 3.6eV to about 4.6eV, about 3.6eV to about 4.5eV, about 3.6eV to about 4.3eV, about 3.9eV to about 4.8eV, about 3.9eV to about 4.6eV, about 3.9eV to about 4.5eV, or about 3.9eV to about 4.3eV.

[0210] The electron injection layer 133e may be thinner than the electron transport layer 133c. For example, the thickness of the electron injection layer 133e may be about 0.01 times to about 0.8 times, about 0.01 times to about 0.7 times, about 0.01 times to about 0.5 times, about 0.1 times to about 0.8 times, about 0.1 times to about 0.7 times, or about 0.1 times to about 0.5 times the thickness of the electron transport layer 133c. The thickness of the electron injection layer 17 may be, for example, less than or equal to about 10 nm, less than or equal to about 7 nm, or less than or equal to about 5 nm. Within a range, the thickness of the electron injection layer 17 may be about 1 nm to about 10 nm, about 1 nm to about 8 nm, about 1 nm to about 7 nm, or about 1 nm to about 5 nm.

[0211] The electron transport layer 133c and the electron injection layer 133e may be formed using one or more suitable methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, sputtering, laser printing, and / or laser induced thermal imaging (LITI) method.

[0212] 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, and the quantum dot film layer is provided on one side of the light-emitting unit.

[0213] like Figure 8 As shown, the quantum dot light-emitting device according to an embodiment of the present disclosure may include a first substrate and a second substrate. The first substrate and the second substrate may be arranged relative to each other. For example, the first substrate may be a substrate provided with components such as a light source, and the second substrate may be a substrate provided with components such as a color filter.

[0214] The first substrate may include a first substrate 11 and a plurality of light emitting units 12 disposed on the first substrate 11 .

[0215] The second substrate may include: a second substrate 51; a quantum dot film layer arranged on the second substrate 51, the quantum dot film layer including at least a plurality of quantum dot structures; a plurality of extinction structures 53 arranged on the side of the quantum dot film layer facing the first substrate, wherein a first channel 54 is formed between any two adjacent extinction structures 53; and a plurality of first optical structures 55 arranged on the side of the quantum dot film layer facing the first substrate, wherein the plurality of first optical structures 55 are respectively located in the first channel 54 between any two adjacent extinction structures 53.

[0216] The quantum dot light emitting device may further include a filling material portion 9 disposed between the first substrate and the second substrate.

[0217] In an embodiment of the present disclosure, the refractive index of the material of the filling material portion 9 is greater than the refractive index of the material of the first optical structure 55 , and the extinction structure 53 includes a light absorbing material.

[0218] like Figure 8 As shown, the orthographic projections of the plurality of light-emitting units 12 on the first substrate 11 at least partially overlap with the orthographic projections of the plurality of first optical structures 55 on the first substrate 11, the orthographic projections of the quantum dot film layer on the first substrate 11 at least partially overlap with the orthographic projections of the plurality of first optical structures 55 on the first substrate 11, and the orthographic projections of the plurality of first optical structures 55 on the first substrate 11 fall within the orthographic projections of the filling material portion 9 on the first substrate 11. The first substrate 11 and the second substrate 51 can be rigid substrates or flexible substrates, including but not limited to glass substrates or polyimide (PI) substrates.

[0219] In an embodiment of the present disclosure, the plurality of light emitting units 12 may include a plurality of organic light emitting diodes or a plurality of inorganic light emitting diodes, such as Mini LEDs or Micro LEDs.

[0220] In an embodiment of the present disclosure, a quantum dot light-emitting device may include a plurality of sub-pixels I, such as the area surrounded by a dotted box. The sub-pixel I may be a third color sub-pixel 10R for emitting light having a first wavelength range, a first color sub-pixel 10G for emitting light having a second wavelength range, and a second color sub-pixel 10B for emitting light having a third wavelength range. Each sub-pixel may include a sub-pixel opening, for example, the third color sub-pixel 10R may include a first sub-pixel opening 561, the first color sub-pixel 10G may include a second sub-pixel opening 562, and the second color sub-pixel 10B may include a third sub-pixel opening 563. The first color, the second color, and the third color may refer to green, blue, and red, respectively. Of course, the quantum dot light-emitting device may also include pixels for emitting other colors, such as pixels emitting yellow light, and the embodiments of the present disclosure do not impose any particular restrictions on them.

[0221] The quantum dot film layer may include multiple quantum dot structures for emitting different colors, and the quantum dot structure includes the first unit of the present disclosure. For example, the quantum dot structure includes a quantum dot body and a first unit, and the first unit is bonded to the surface of the quantum dot body. For example, the third color sub-pixel 10R may include a first quantum dot structure 521 for emitting light having a first wavelength range, and the first color sub-pixel 10G may include a second quantum dot structure 522 for emitting light having a second wavelength range. Of course, the quantum dot film layer may also include quantum dot structures for emitting light having other wavelength ranges, such as a quantum dot structure that emits yellow light.

[0222] The second substrate may further include a plurality of light blocking structures 57 disposed on the second substrate 51, wherein the plurality of light blocking structures 57 are located between the layer where the extinction structure 53 is located and the layer where the quantum dot film layer 52 is located. For example, the light blocking structures 57 include light blocking materials.

[0223] A second channel 58 is formed between any two adjacent light blocking structures 57 , and the orthographic projection of the second channel 58 on the second substrate 51 falls within the orthographic projection of the first channel 54 on the second substrate 51 . Multiple first channels 54 and multiple second channels 58 are respectively connected to form multiple light input channels.

[0224] The second substrate may further include a plurality of quantum dot protection structures 59 disposed on the second substrate 51. The plurality of quantum dot protection structures 59 are located between the quantum dot film layer 52 and the first optical structure 55. The orthographic projections of the plurality of quantum dot protection structures 59 on the second substrate 51 are respectively located within the orthographic projections of the plurality of second channels 58 on the second substrate 51. In this manner, the plurality of quantum dot protection structures 59 respectively protect the quantum dot structures located in each pixel opening.

[0225] The second substrate may further include a plurality of retaining wall structures 60 arranged on the second substrate 51, the plurality of retaining wall structures 60 being located between the second substrate 51 and the plurality of extinction structures 53, and the orthographic projections of the plurality of retaining wall structures 60 on the second substrate 51 being respectively located within the orthographic projections of the plurality of extinction structures 53 on the second substrate 51.

[0226] The above-mentioned pixel openings 561, 562, 563 are located between any two adjacent retaining wall structures 60, and the orthographic projections of each pixel opening 561, 562, 563 on the first substrate 11 respectively cover the orthographic projections of multiple light input channels on the first substrate 11, and the orthographic projections of each pixel opening 561, 562, 563 on the first substrate 11 respectively cover the orthographic projections of multiple light-emitting units 12 on the first substrate 11.

[0227] The present disclosure also provides a method for preparing a quantum dot light-emitting device, comprising:

[0228] Providing a first color quantum dot-ligand solution, wherein the first color quantum dot-ligand solution is a mixed solution comprising first color quantum dots and the quantum dot ligands in any one of the above embodiments;

[0229] Providing a second color quantum dot-ligand solution, wherein the second color quantum dot-ligand solution is a mixed solution comprising second color quantum dots and the quantum dot ligands in any of the above embodiments;

[0230] Coating a first color quantum dot-ligand solution on a substrate, exposing and developing the solution to form a first color sub-pixel;

[0231] Coating a second color quantum dot-ligand solution on the substrate, exposing and developing the solution to form a second color sub-pixel;

[0232] The method for preparing a quantum dot light-emitting device provided by the present disclosure further includes:

[0233] Providing a third color quantum dot-ligand solution, wherein the third color quantum dot-ligand solution is a mixed solution comprising third color quantum dots and the quantum dot ligands in any one of the above embodiments;

[0234] A third color quantum dot-ligand solution is coated on the substrate, and exposed and developed to form a third color sub-pixel.

[0235] In the present disclosure, the first color, the second color, and the third color merely illustrate that the colors thereof are different from each other, but no special limitation is imposed on the specific colors they represent.

[0236] The present disclosure also provides a display device comprising the aforementioned quantum dot light-emitting device. The display device of the present disclosure can be a mobile phone, tablet computer, television, or other electronic device, which are not listed here one by one.

[0237] First ligand solubility test

[0238] In this example, the development and elution effects of quantum dots using the first ligand were tested against quantum dots using other ligands in the related art. Specifically, the test was conducted using a thiopropionic acid ligand as the first ligand and isooctylthiol or oleic acid ligands as the other ligands. The specific steps are as follows:

[0239] (1) Quantum dots containing different ligands were spin-coated on a 2 cm × 2 cm glass substrate;

[0240] (2) Soak the above quantum dot film in 10 mL of developer solution, ultrasonicate for 5 minutes, then take it out and rinse it with developer solution 3-8 times, and then blow dry it with a nitrogen gun;

[0241] (3) Transfer all the above samples to a PTFE (polytetrafluoroethylene) beaker, add 5 mL of aqua regia, and digest on a hot plate at 180°C until there is no obvious reaction and 0.5 mL of solution remains. Remove and cool to room temperature, and dilute to 5 mL with ultrapure water;

[0242] (4) The sample solution was diluted to a certain multiple and directly tested on an ICP-MS instrument (iCAP Q, Thermo, Waltham, USA). All acids used were MOS grade, and ultrapure water was prepared by Millipore.

[0243] After conversion, the content of the elements to be tested in the sample is shown in Table 1 below

[0244] Table 1 Comparison of Cd residual amounts after development of quantum dots with different ligands (glass substrate)

[0245]

[0246]

[0247] As can be seen from Table 1, using the first ligand (mercaptopropionic acid) disclosed herein as a ligand with a "developing function" can significantly reduce the amount of quantum dots remaining after development and elution.

[0248] Quantum dot-ligand system:

[0249] The first ligand (MPA: mercaptopropionic acid), the second ligand is (MMES: mono-2-(methacryloyloxy)ethyl succinate) as an example:

[0250] (1) Mixture of quantum dots and quantum dot-ligand mixtures

[0251] a. Prepare MPA-methanol diverter and adjust the pH to 11-12 with sodium hydroxide solution;

[0252] b. adding the quantum dot bulk solution to the diverting agent and stirring to obtain a first mixed solution;

[0253] c. Add deionized water of the same volume as the first mixed solution, stir for 10 minutes, and then centrifuge and wash. Centrifuge twice with an acetone / methanol mixed solvent to obtain a quantum dot body-first ligand material in which the first ligand (MPA) is connected to the quantum dot body.

[0254] e. Add the second ligand (MMES) to the PGMEA solution of the quantum dot body and the first ligand, stir for 4 hours, wash with anhydrous ethanol by centrifugation, and dry.

[0255] f. Take an appropriate amount of the product in step e and dissolve it in PGMEA, add the second ligand (MMES) again and stir overnight, wash it by centrifugation with anhydrous ethanol, and dry it for 3 hours to obtain a PGMEA solution in which a certain mass concentration of the first ligand (MPA) and the second ligand (MMES) mixed ligand is connected to the quantum dot body.

[0256] The structure of the mixed ligands of the first ligand (MPA) and the second ligand (MMES) connected to the quantum dot body is as follows:

[0257]

[0258] When the first ligand and the second ligand have other structures, or there is a third ligand, the quantum dot body and the quantum dot mixed ligand can be mixed with reference to the above steps.

[0259] Specifically, when the first ligand is The second ligand is When the first ligand and the second ligand are mixed and connected to the quantum dot body, the structure is as follows:

[0260]

[0261] When the first ligand is The second ligand is When the first ligand and the second ligand are mixed and connected to the quantum dot body, the structure is as follows:

[0262]

[0263] When the first ligand is The second ligand is When n4 is selected from any integer between 2 and 4, the structure of the mixed ligand of the first ligand and the second ligand connected to the quantum dot body is as follows:

[0264]

[0265] When a third ligand is also contained, the third ligand can also be connected to the quantum dot body. Taking n5 as an example, where n5 is selected from any integer between 1 and 100, the structure of the mixed ligands of the first ligand, the second ligand, and the third ligand connected to the quantum dot body is as follows:

[0266]

[0267] (2) Mixture of photoinitiator, quantum dot body and quantum dot mixed ligand

[0268] Add a photosensitive initiator to the solution obtained in step (1), and the photosensitive initiator accounts for 1%-5% of the weight of the quantum dot body in terms of weight percentage.

[0269] Photolithography process forms quantum dot film layer

[0270] (1) Providing a quantum dot-ligand mixed solution, wherein the quantum dot-ligand solution is a mixed solution comprising a quantum dot body, a photosensitive initiator and a quantum dot mixed ligand, that is, the above-mentioned quantum dot-ligand system.

[0271] (2) coating a quantum dot-ligand mixed solution on a substrate and performing an exposure treatment, so that the photoinitiator generates free radicals and crosslinks the carbon-carbon double bonds in the photosensitive group; or the photoinitiator generates hydrogen ions and causes the saturated 3-5-membered heterocyclic group containing O or S in the photosensitive group to open and crosslink;

[0272] (3) Performing development treatment to form a quantum dot film layer.

[0273] Steps (2) and (3) may specifically include the following operations:

[0274] like Figures 1 to 2 As shown, a first color quantum dot-ligand solution is coated on a substrate 1 to form a first color quantum dot film layer 21, and a first patterning (Photo Mask) process is performed, and the entire layer is exposed to ultraviolet light; then, one or more mixed solvents of ethanol, isopropanol, propanol, n-butanol, DMF, and DMSO are used as developers for rinsing and development; after development, the substrate is again heated in a 90°C environment for 120s to remove the developer, thereby forming a first color sub-pixel 211.

[0275] like Figures 3 and 4 As shown, a second color quantum dot-ligand solution is applied to form a second color quantum dot film layer 22, a second photo mask is applied, and the entire layer is exposed to ultraviolet light, and then developed and fixed to form a second color sub-pixel 221;

[0276] like Figures 5 and 6As shown, finally, a third color quantum dot-ligand solution is applied to form a third color quantum dot film layer 23 , a third photo mask is applied, and the entire layer is exposed to ultraviolet light, and then developed and fixed to form a third color sub-pixel 231 .

[0277] The structure containing carbon-carbon double bond in the photosensitive group For example, after exposure and development, the structure of the exposure area changes as follows:

[0278]

[0279] The changes in the structure of the non-exposed area are as follows:

[0280]

[0281] The structure containing epoxy group in the photosensitive group For example, after exposure and development, the structure of the exposure area changes as follows:

[0282]

[0283] The changes in the structure of the non-exposed area are as follows:

[0284]

[0285] The structure of the ligand containing a carbon-carbon double bond or an epoxy group in the photosensitive group disclosed herein can refer to the above two reaction formulas.

[0286] Display panel preparation example

[0287] The display panel includes a quantum dot light-emitting device, which includes 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 stacked in sequence.

[0288] The display panel preparation method specifically includes the following steps:

[0289] The transparent substrate is cleaned using standard methods, followed by the deposition of 200nm of Mo metal for the gate and patterning; 150nm of SiO2 for the gate dielectric; 40nm of IGZO for the active layer and patterning; 200nm of Mo metal for the source and drain electrodes and patterning; 300nm of SiO2 for the passivation layer and patterning; and 40nm of ITO for the pixel electrode and patterning. Finally, an acrylic material is spin-coated and deposited, and then photolithography and curing are performed to form a pixel definition layer of approximately 1.5um, forming the TFT backplane.

[0290] Before preparing quantum dot light-emitting devices (QD-LEDs), the surface of the TFT backplane is treated with plasma.

[0291] The hole injection layer and the hole transport layer are prepared by spin coating process, such as spin coating PEDOT (poly 3,4-ethylenedioxythiophene): PSS (polystyrene sulfonic acid) and TFB respectively; the overall thickness thereof is 50-100 nm.

[0292] The above-mentioned photolithography process is used to form a quantum dot film layer, specifically including applying a first color quantum dot-ligand solution, adding a first photo mask, exposing the entire surface to ultraviolet light, and then developing and fixing to form a first color sub-pixel; then applying a second color quantum dot-ligand solution, adding a second photo mask, exposing the entire surface to ultraviolet light, and then developing and fixing to form a second color sub-pixel; finally, applying a third color quantum dot-ligand solution, adding a third photo mask, exposing the entire surface to ultraviolet light, and then developing and fixing to form a third color sub-pixel.

[0293] The electron transport layer and the electron injection layer are formed by spin coating or evaporation, such as ZnO nanoparticles.

[0294] A thin cathode metal layer is evaporated. The cathode can be an Al layer, etc., with a thickness of about 500-1000nm. After the evaporation is completed, it is packaged and cut to complete the preparation of the entire display panel.

[0295] The light output mode of the AMQLED device can be bottom light output, the minimum sub-pixel area that can be produced is 10-30 microns, and the display panel is about 300-800ppi.

[0296] It should be noted that although the steps of the method of the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all steps must be performed to achieve the desired results. Additional or alternative steps, such as omitting certain steps, combining multiple steps into one step, and / or decomposing a step into multiple steps, should all be considered part of this disclosure.

[0297] It should be understood that the present disclosure is not limited in its application to the detailed structure and arrangement of the components set forth in this specification. The present disclosure is capable of other embodiments and can be implemented and executed in a variety of ways. The aforementioned variations and modifications fall within the scope of the present disclosure. It should be understood that the present disclosure disclosed and defined in this specification extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or the drawings. All of these different combinations constitute multiple alternative aspects of the present disclosure. The embodiments of this specification illustrate the best mode known for implementing the present disclosure and will enable those skilled in the art to utilize the present disclosure.

Claims

1. A quantum dot mixed ligand, characterized in that: include: A first ligand comprising a first coordinating group, a first connecting group and an acidic group, wherein the first connecting group is connected between the first coordinating group and the acidic group; A second ligand comprises a second coordination group, a second linking group and a photosensitive group, wherein the second linking group is connected between the second coordination group and the photosensitive group; The first coordination group and the second coordination group are used to form a coordination bond with the quantum dot body; the acidic group can react with the alkaline solution to ionize the first ligand; Wherein, the first ligand has a structure as shown in Formula I; Wherein, R1 is a first coordination group selected from thiol or dithiol; R2 is an acidic group selected from a carboxylic acid group or a sulfonic acid group; n1 is any integer selected from 0-5; Wherein, the second ligand is selected from the group consisting of the following structures: wherein R4 is selected from a carboxylic acid group, a thiol group or a dithiol group; n2 is any integer selected from 2 to 8; n3 is selected from any integer between 2 and 8.

2. The quantum dot hybrid ligand according to claim 1, characterized in that The quantum dot mixed ligand further comprises: A third ligand having a structure as shown in Formula II; wherein R5 is selected from a thiol group or a dithiol group; R6 is selected from a carboxylic acid group or a sulfonic acid group; n5 is selected from any integer between 1 and 100.

3. The quantum dot hybrid ligand according to claim 2, characterized in that When the quantum dot mixed ligand comprises the first ligand and the second ligand, the quantum dot mixed ligand comprises 10%-50% of the first ligand and 50%-90% of the second ligand by weight percentage; When the quantum dot mixed ligand comprises the first ligand, the second ligand and the third ligand, the quantum dot mixed ligand comprises 10%-30% of the first ligand, 40%-60% of the second ligand and 10%-30% of the third ligand by weight.

4. The quantum dot hybrid ligand according to claim 2, characterized in that When the quantum dot mixed ligand comprises the first ligand and the second ligand, the first ligand and the second ligand account for 100% of the weight of the quantum dot mixed ligand; When the quantum dot mixed ligand comprises the first ligand, the second ligand and the third ligand, the first ligand, the second ligand and the third ligand account for 100% of the weight of the quantum dot mixed ligand.

5. A quantum dot-ligand system, characterized in that: The method comprises a quantum dot body, a photosensitive initiator and the quantum dot mixed ligand according to any one of claims 1 to 4.

6. The quantum dot-ligand system according to claim 5, characterized in that In terms of weight percentage, the photosensitive initiator accounts for 1%-5% of the weight of the quantum dot body.

7. The quantum dot-ligand system according to claim 5, characterized in that When the photosensitive group is selected from a structure containing a carbon-carbon double bond, the photoinitiator is selected from a photosensitive free radical initiator.

8. The quantum dot-ligand system according to claim 5, characterized in that When the photosensitive group is selected from epoxy groups, the photoinitiator is selected from photoacid generators.

9. A quantum dot-ligand material, characterized in that Comprising a first quantum dot body, a second quantum dot body and a quantum dot mixed ligand according to any one of claims 1 to 4; Wherein, the second ligand is connected to the first quantum dot body and the second quantum dot body respectively through coordination bonds; The first quantum dot body and the second quantum dot body are cross-linked through the photosensitive group in the second ligand to form a network structure.

10. A method for preparing a quantum dot pattern, characterized in that: include: Providing a quantum dot-ligand mixed solution, wherein the quantum dot-ligand solution is a mixed solution comprising a quantum dot body, a photoinitiator and the quantum dot mixed ligand according to any one of claims 1 to 4; The quantum dot-ligand mixed solution is coated on a substrate and subjected to an exposure treatment, so that the photoinitiator generates free radicals and crosslinks the carbon-carbon double bonds in the photosensitive groups; or the photoinitiator generates hydrogen ions and causes the epoxy groups in the photosensitive groups to open and crosslink; A development process is performed to form the quantum dot pattern.

11. A quantum dot light-emitting device, characterized in that: It comprises a functional layer, wherein the functional layer comprises a quantum dot film layer, and the quantum dot film layer comprises the quantum dot-ligand material according to claim 9.

12. The quantum dot light-emitting device according to claim 11, characterized in that: The quantum dot light-emitting device further includes an anode and a cathode, and the functional layer is located between the anode and the cathode.

13. The quantum dot light-emitting device according to claim 11, characterized in that: The quantum dot light-emitting device further includes a light-emitting unit, and the quantum dot film layer is arranged on one side of the light-emitting unit.

14. A method for preparing a quantum dot light-emitting device, characterized in that: include: Providing a first color quantum dot-ligand mixed solution, wherein the first color quantum dot-ligand solution is a mixed solution comprising a first color quantum dot body, a photosensitive initiator, and the quantum dot mixed ligand according to any one of claims 1 to 4; Providing a second color quantum dot-ligand mixed solution, wherein the second color quantum dot-ligand solution is a mixed solution comprising a second color quantum dot body, a photosensitive initiator, and the quantum dot mixed ligand according to any one of claims 1 to 4; Coating the first color quantum dot-ligand mixed solution on the substrate, exposing and developing the solution to form first color sub-pixels; The second color quantum dot-ligand mixed solution is coated on the substrate, and exposed and developed to form second color sub-pixels.

15. A display device, characterized in that: The device comprises a quantum dot light-emitting device as described in any one of claims 11 to 13.

Images