Quantum dot ink, quantum dot layer patterning method and quantum dot light-emitting device

Abstract

The invention discloses quantum dot ink, a quantum dot layer patterning method and a quantum dot light-emitting device.When the quantum dot ink is used for manufacturing a patterned quantum dot layer, due to the fact that first ligands on the surfaces of quantum dots change under the action of illumination (such as ultraviolet irradiation exposure) and a photoinduced base generator, the quantum dot layer is patterned, and the quantum dot layer is patterned. According to the method, the quantum dot material is added into the exposure region to change the solubility of the quantum dot material, so that the solubility of the quantum dot material in the exposure region is different from that of the quantum dot material in the non-exposure region, a proper developing solution can be selected to elute and remove the quantum dots in the non-exposure region, and a patterned quantum dot layer is formed in the exposure region. Therefore, the quantum dot ink provided by the embodiment of the invention can directly form a patterned quantum dot layer through a photoetching process, the technical difficulty that a higher-precision printing nozzle is needed to improve the resolution by adopting an ink-jet printing process in the related technology is avoided, and the production of a high-resolution QLED product can be effectively realized.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and in particular, to a quantum dot ink, a method for patterning a quantum dot layer, and a quantum dot light-emitting device. Background Art

[0002] Quantum dots (QDs), also known as nanocrystals, are nanoparticles composed of group II-VI or III-V elements. The particle size of quantum dots generally ranges from 1 to 20 nm. Due to the quantum confinement of electrons and holes, the continuous energy band structure becomes a discrete energy level structure, and fluorescence can be emitted after being excited.

[0003] With the in-depth development of quantum dot preparation technologies, the stability and luminescence efficiency of quantum dots have been continuously improved, and the research on quantum dot light-emitting diodes (QLEDs) has been continuously deepened. The application prospect of QLEDs in the display field is becoming increasingly bright. However, at present, the production efficiency of QLEDs has not reached the mass production level. The most important reason is that the high-resolution patterning technology of QLEDs has not yet achieved a breakthrough. The inorganic nanoparticle characteristics of quantum dots make it impossible to form a film and pattern by evaporation; it is difficult to achieve a high resolution by inkjet printing. Summary of the Invention

[0004] Embodiments of the present disclosure provide a quantum dot ink, a method for patterning a quantum dot layer, and a quantum dot light-emitting device. The specific solutions are as follows:

[0005] A quantum dot ink provided by an embodiment of the present disclosure includes a quantum dot material and a photoacid generator. The quantum dot material includes quantum dots and a first ligand connected to the surface of the quantum dots. The quantum dot material is configured such that under the action of light and the photoacid generator, the first ligand on the surface of the quantum dots changes to change the solubility of the quantum dot material.

[0006] Optionally, in the above quantum dot ink provided by an embodiment of the present disclosure, the quantum dot ink further includes a crosslinking agent. The first ligand includes a first crosslinking group, and the crosslinking agent includes a second crosslinking group. One of the first crosslinking group and the second crosslinking group is a thiol group, and the other of the first crosslinking group and the second crosslinking group is a group capable of undergoing a crosslinking reaction with the thiol group and the photoacid generator under light irradiation.

[0007] Optionally, in the above quantum dot ink provided by an embodiment of the present disclosure, the other of the first crosslinking group and the second crosslinking group includes at least one of a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, and an isocyanate group.

[0008] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the crosslinking agent includes at least two of the second crosslinking groups.

[0009] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the crosslinking agent further includes a solubility regulating structure connected to the second crosslinking group.

[0010] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the solubility regulating structure includes at least one weakly polar group and a hydrocarbon group with a carbon chain length greater than or equal to 10 carbon atoms, or the solubility regulating structure includes at least one strongly polar group and a hydrocarbon group with a carbon chain length less than 10 carbon atoms.

[0011] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the weakly polar group includes methyl, phenyl or aldehyde group, and the strongly polar group includes sulfonic acid, carboxyl group, nitroso group, cyano group, hydroxyl group, amide group, phenolic hydroxyl group, mercapto group or amino group.

[0012] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the first ligand further includes: a linking group connected to the first crosslinking group, and a coordinating group connected to the linking group; the coordinating group is configured to coordinate with the quantum dot.

[0013] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the coordinating group includes -NH 2 , -SH, -COOH, -P, -P=O, etc.

[0014] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the linking group is an alkyl chain segment or a polyether chain segment.

[0015] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the alkyl chain segment has at least one double bond or benzene ring group, or the alkyl chain segment is a straight-chain alkyl containing 1C-30C;

[0016] The polyether chain segment includes polyethylene oxide.

[0017] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the photo-base generator includes at least one of cobalamin complex, quaternary ammonium salt, carbamate, oxime ester, amidine, guanidine, -aminoketone, polyazaheterocycle, tetraphenylborate, etc.

[0018] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the photo-base generator is configured to generate a second ligand under light illumination, and the polarity of the second ligand is opposite to that of the first ligand; the second ligand includes a basic group containing a lone pair of electrons, and the basic group is configured to coordinate with the surface of the quantum dot so that the second ligand displaces the first ligand.

[0019] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the basic group is an amino group.

[0020] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the first ligand has a weak polarity and the second ligand has a strong polarity; or, the first ligand has a strong polarity and the second ligand has a weak polarity.

[0021] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the first ligand includes: a coordination group that coordinates with the quantum dot, and a first polar group connected to the coordination group; the second ligand further includes a second polar group connected to the basic group; wherein,

[0022] One of the first polar group and the second polar group includes an alkyl chain segment or a polyether chain segment and a hydrocarbon group with a carbon chain length greater than 10 carbon atoms, and the other of the first polar group and the second polar group includes at least one of sulfonic acid, carboxyl group, nitroso group, cyano group, hydroxyl group, amide group, phenolic hydroxyl group, mercapto group, amino group, etc. and a hydrocarbon group with a carbon chain length less than 10 carbon atoms.

[0023] Optionally, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the structural general formula of the photo-base generator is: Wherein, R1 and R2 are respectively an alkyl chain, an alkene chain, and contain at least one of phenyl, ester group, carbonyl group, and ether bond.

[0024] Correspondingly, the embodiments of the present disclosure also provide a method for patterning a quantum dot layer, including:

[0025] Forming a quantum dot thin film by using the above-mentioned quantum dot ink provided by the embodiments of the present disclosure;

[0026] Under the shielding of a mask, exposing the quantum dot thin film to light, and the first ligand of the quantum dot material changes under the action of light illumination and the photo-base generator, and the solubility of the quantum dot material changes;

[0027] Using a developer to elute and remove the quantum dots in the unexposed area to obtain a patterned quantum dot layer.

[0028] Optionally, in the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure, the first ligand of the quantum dot material in the exposed area changes under the action of light and a photoacid generator. Specifically:

[0029] The first crosslinking group of the first ligand in the exposed area and the second crosslinking group of the crosslinking agent undergo a crosslinking reaction under the action of the base generated by the photoacid generator.

[0030] Optionally, in the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure, the first ligand of the quantum dot material in the exposed area changes under the action of light and a photoacid generator. Specifically:

[0031] The basic group of the second ligand generated by the photoacid generator in the exposed area coordinates with the surface of the quantum dot, so that the second ligand displaces the first ligand.

[0032] Correspondingly, the embodiments of the present disclosure also provide a quantum dot layer, which includes a plurality of patterned sub-pixels. Each sub-pixel includes a quantum dot material, and the quantum dot material includes quantum dots and a crosslinking network connected to the surface of the quantum dots. The crosslinking network includes at least one of the following structures:

[0033]

[0034] Optionally, in the above-mentioned quantum dot layer provided by the embodiments of the present disclosure, the structure of the crosslinking network is

[0035]

[0036]

[0037] Correspondingly, the embodiments of the present disclosure also provide a quantum dot layer, which includes a plurality of patterned sub-pixels. Each sub-pixel includes a quantum dot material, and the quantum dot material includes quantum dots and a first ligand and a second ligand connected to the surface of the quantum dots. The polarity of the second ligand is opposite to that of the first ligand, and the second ligand includes a basic group containing a lone pair of electrons.

[0038] Optionally, in the above-mentioned quantum dot layer provided by the embodiments of the present disclosure, the general structural formula of the second ligand is: Wherein, R1 is at least one of an alkyl chain, an alkene chain, a phenyl group, an ester group, a carbonyl group, and an ether bond.

[0039] Correspondingly, the embodiments of the present disclosure also provide a quantum dot light-emitting device, which includes the above-mentioned quantum dot layer provided by the embodiments of the present disclosure.

[0040] Correspondingly, an embodiment of the present disclosure further provides a method for manufacturing a quantum dot light-emitting device, including forming a quantum dot layer by using the above-mentioned quantum dot layer patterning method provided by the embodiment of the present disclosure.

[0041] Correspondingly, an embodiment of the present disclosure further provides a display device, including the above-mentioned quantum dot light-emitting device provided by the embodiment of the present disclosure.

[0042] The beneficial effects of the embodiments of the present disclosure are as follows:

[0043] A quantum dot ink, a quantum dot layer patterning method, and a quantum dot light-emitting device provided by an embodiment of the present disclosure. When using the quantum dot ink of the present disclosure to fabricate a patterned quantum dot layer, due to the action of light (such as ultraviolet light exposure) and a photoacid generator, the first ligand on the surface of the quantum dots changes to alter the solubility of the quantum dot material. In this way, the solubility of the quantum dot material in the exposed area is different from that in the non-exposed area, so that a suitable developer can be selected to wash away the quantum dots in the non-exposed area, and a patterned quantum dot layer is formed in the exposed area. Therefore, the quantum dot ink provided by the embodiment of the present disclosure can directly form a patterned quantum dot layer through a photolithography process, avoiding the technical difficulty of using an inkjet printing process that requires a higher-precision print head to improve the resolution in the related art. The present disclosure can effectively realize the production of high-resolution QLED products. Description of the Drawings

[0044] Figure 1 Schematic diagram of the reaction mechanism of the click chemical reaction between the mercapto group of the first ligand in the exposed area and the epoxy group of the cross-linking agent;

[0045] Figure 2 Schematic diagram of the reaction mechanism of the click chemical reaction between the mercapto group of the first ligand in the exposed area and the carbon-carbon double bond of the cross-linking agent;

[0046] Figure 3 Schematic diagram of the principle of the photoacid generator generating a second ligand with an amino group to guide quantum dot lithography patterning after light exposure;

[0047] Figure 4 Schematic diagram of the reaction mechanism of the second ligand replacing the first ligand;

[0048] Figure 5 Flowchart of the manufacturing method of the quantum dot layer patterning method provided by the embodiment of the present disclosure;

[0049] Figures 6A - 6L Schematic diagram of the structure after each step is executed in the manufacturing method of the quantum dot light-emitting device provided by the embodiment of the present disclosure;

[0050] Figure 7 Schematic diagram of the structure of another quantum dot light-emitting device provided by the embodiment of the present disclosure. Detailed implementation manners

[0051] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are only a part rather than all of the embodiments of the present disclosure. And, without conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0052] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The words such as "including" or "comprising" used in the present disclosure mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. The words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "inner", "outer", "upper" and "lower" are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0053] It should be noted that the sizes and shapes of the various figures in the drawings do not reflect the true scale, and the purpose is only to schematically illustrate the content of the present disclosure. And the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout.

[0054] The surface ligands with photo-responsiveness endow the quantum dots with the function of direct photolithographic patterning. The main principle is to utilize the photoreaction of the photosensitive groups to change the surface chemistry of the quantum dots, thereby causing changes in the solubility and colloidal stability of the quantum dots. Therefore, an efficient photoreaction is the basis for realizing the photolithographic patterning of quantum dots.

[0055] The embodiments of the present disclosure provide a quantum dot ink, which includes a quantum dot material and a photoacid generator. The quantum dot material includes quantum dots and a first ligand connected to the surface of the quantum dots. The quantum dot material is configured such that under the action of light and the photoacid generator, the first ligand on the surface of the quantum dots changes to change the solubility of the quantum dot material.

[0056] When the quantum dot ink provided by the embodiments of the present disclosure is used to fabricate a patterned quantum dot layer, due to the action of light (such as ultraviolet light exposure) and a photoacid generator, the first ligand on the surface of the quantum dots changes to alter the solubility of the quantum dot material. In this way, the solubility of the quantum dot material in the exposed area is different from that in the non-exposed area, so that a suitable developer can be selected to wash away the quantum dots in the non-exposed area, and a patterned quantum dot layer is formed in the exposed area. Therefore, the quantum dot ink provided by the embodiments of the present disclosure can directly form a patterned quantum dot layer through a photolithography process, avoiding the technical difficulty of using an inkjet printing process in the related art that requires a higher-precision print head to improve the resolution. The present disclosure can effectively realize the production of high-resolution QLED products.

[0057] In a specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the quantum dot ink further includes a crosslinking agent. The first ligand includes a first crosslinking group, and the crosslinking agent includes a second crosslinking group. One of the first crosslinking group and the second crosslinking group is a mercapto group, and the other of the first crosslinking group and the second crosslinking group is a group that can undergo a crosslinking reaction with the mercapto group and the photoacid generator under light. In this way, when forming a patterned quantum dot layer, exposure is carried out under the shielding of a mask. The photoacid generator generates an alkali after being irradiated by light, and the alkali catalyzes the click chemical reaction of the mercapto group series, thereby causing a change in the solubility of the quantum dot material. Using the original good solvent as the developer, the quantum dot material in the non-exposed area is washed away by the original solvent, and the first crosslinking group and the second crosslinking group in the exposed area undergo a crosslinking reaction to form a crosslinked network and are retained, so that a patterned quantum dot layer is formed in the exposed area.

[0058] In a specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the other of the first crosslinking group and the second crosslinking group includes at least one of a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, and an isocyanate group. The alkali generated after the photoacid generator is irradiated by light can catalyze the click chemical reaction between the carbon-carbon double bond and the mercapto group, between the carbon-carbon triple bond and the mercapto group, between the epoxy group and the mercapto group, and between the isocyanate group and the mercapto group. Thus, a stable crosslinked network is formed between the quantum dots in the exposed area, so that the solubility of the quantum dot material in the exposed area is very different from that of the quantum dot material in the non-exposed area. Therefore, the quantum dots in the non-exposed area are washed away by the original solvent, and a patterned quantum dot layer is formed in the exposed area.

[0059] Optionally, the first crosslinking group of the first ligand and the second crosslinking group of the crosslinking agent are different reactive functional groups that undergo click chemical reactions. When the first crosslinking group of the first ligand is a thiol group, the second crosslinking group of the crosslinking agent is a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, or an isocyanate group; conversely, when the first crosslinking group of the first ligand is a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, or an isocyanate group, the second crosslinking group of the crosslinking agent is a thiol group.

[0060] Taking the click chemical reaction of base-catalyzed Michael addition of a thiol (R'-SH) to a carbon-carbon double bond as an example, its mechanism is as follows:

[0061] Initiation

[0062]

[0063] Propagation(polar solvent)

[0064]

[0065] Propagation(non-polar solvent)

[0066]

[0067] Among them, B is a base, and R and R' can be an alkyl chain, a hydrocarbon chain, an ester group, a carbonyl group, etc.

[0068] Specifically, the principles of click chemical reactions of a thiol group with a carbon-carbon triple bond, an epoxy group, and an isocyanate group are similar to those of the click chemical reaction of a thiol group with a carbon-carbon double bond, and will not be elaborated here.

[0069] In specific implementation, to improve the stability of the crosslinked network, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the crosslinking agent includes at least two second crosslinking groups. The more the number of second crosslinking groups, the stronger the subsequent reaction degree with the first crosslinking group of the first ligand, and the better the patterning effect of the quantum dot layer.

[0070] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the cross-linking agent further includes a solubility regulation structure connected to the second cross-linking group. In this way, a suitable solubility regulation structure can be selected according to the solvent polarity of the quantum dot ink. For example, in a non-polar solvent, the solubility regulation structure includes at least one weakly polar group and a hydrocarbon group with a carbon chain length greater than or equal to 10 carbon atoms. The weakly polar group includes, for example, a methyl group, a phenyl group, an aldehyde group, etc.; in a polar solvent, the solubility regulation structure includes at least one strongly polar group and a hydrocarbon group with a carbon chain length less than 10 carbon atoms. The strongly polar group includes, for example, sulfonic acid, carboxyl group, nitroso group, cyano group, hydroxyl group, amide group, phenolic hydroxyl group, mercapto group, or amino group, etc.

[0071] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the first ligand on the surface of the quantum dot further includes: a linking group connected to the first cross-linking group, and a coordinating group connected to the linking group; the coordinating group is configured to coordinate and bind with the quantum dot. For example, the structural general formula of the first ligand is D-E-F, where D is a coordinating group (anchoring group) that coordinates with the surface of the quantum dot, and D can be one or more of a mercapto group (-SH), a carboxyl group (-COOH), an amino group (-NH2), a phosphino group (-P-), a phosphinoxy group (-P=O); E is a linking group, which is an alkyl chain segment or a polyether chain segment (such as polyethylene oxide, etc.), and the alkyl chain segment has at least one double bond or benzene ring group. The alkyl chain segment is preferably a straight-chain alkyl group containing 1C-30C; F is the first cross-linking group (a functional group capable of undergoing click chemical reaction), and F includes but is not limited to a mercapto group, a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, and an isocyanate. Among them, the more the number of F, the stronger the subsequent reaction degree with the cross-linking agent, and the better the patterning effect of the quantum dots.

[0072] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the photo-base generator is a photoinitiator that can generate basic species after illumination. The photo-base generator mainly includes at least one of cobalamin complexes, quaternary ammonium salts, carbamates, oxime esters, amidines, guanidines, α-amino ketones, polyazacyclic compounds, and tetraphenyl borate salts. Considering solubility, the photo-base generator is preferably a non-ionic photo-base generator, such as carbamates, oxime esters, amidines, guanidines, α-amino ketones, and polyazacyclic compounds.

[0073] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the quantum dot ink further includes a solvent, and the solvent includes a polar solvent and a non-polar solvent. Specifically, the non-polar solvent is characterized in that the dielectric constant of the solvent is less than 3.6, such as cyclohexane, petroleum ether, octane, trimethylpentane, carbon tetrachloride, trichlorotrifluoroethane, p-xylene, chlorobenzene, o-dichlorobenzene, diethyl ether, diethyl ether, tetrahydrofuran, hexane, pentane, toluene, chlorobenzene, etc.; the polar solvent is characterized in that the dielectric constant of the solvent is greater than 3.6, such as methanol, ethanol, isopropanol, ethyl acetate, acetonitrile, propylene glycol methyl ether acetate, acetone, acetic acid, pyridine, N,N-dimethylformamide, dimethyl sulfoxide, etc. The polar solvent or non-polar solvent can be selected according to the polarity of the first ligand of the quantum dot material.

[0074] Optionally, the quantum dot is a semiconductor nanocrystal with quantum confinement effect, including but not limited to II-VI group quantum dots, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgSe, HgTe, HgS, HgxCd1-xTe, HgxCd1-xS, HgxCd1-xSe, HgxZn1-xTe, CdxZn1-xSe, or CdxZn1-xS, where 0 < x < 1; or the quantum dot is a III-V group quantum dot, such as InP, InAs, InSb, GaAs, GaP, GaN, GaSb, InN, InSb, AlP, AlN, AlAs; or a VI-VI group quantum dot, such as PbS, PbSe, PbTe; or, the quantum dot can be a quantum dot with a core-shell structure, including CdSe@ZnS, CdSe@CdS, InP@ZnS, CdTe@CdSe, CdSe@ZnTeZnTe@CdSe, ZnSe@CdS or Cd1-xZnxS@ZnS; or the quantum dot is an ABX 3 type perovskite quantum dot or nanocrystal, A is CH 3 NH 3+ (methylamine), NH 2 CH=NH 2 (formamidine), Cs + or one or more of them, B is Pb 2+ 、Sn 2+ or one or two of them, X is Cl - 、Br - 、I - or one or more of them, for example, including CH 3 NH 3 PbBr 3 、CH 3 NH3PbCl 3 、CH 3 NH 3 PbI 3, CsPbBr 3 , CsPbCl 3 , CsPbI 3 ; or other quantum dots, such as CuInS 2 , CuInSe 2 , AgInS 2 etc., as long as the quantum dots with an organic ligand coating can be applied.

[0075] Taking the first crosslinking structure of the first ligand in the quantum dot ink as a mercapto group and the second crosslinking structure of the crosslinking agent as an epoxy group as an example, the method for patterning the quantum dot layer will be described. Among them, the first ligand on the surface of the quantum dot is a polythiol (structure ), the crosslinking agent is a polyepoxy (structure ), the photoacid generator is an xanthene-reduced amidine photoacid generator (X-DBN), and the solvent is propylene glycol monomethyl ether acetate.

[0076] First, synthesize a quantum dot material with oleic acid as the ligand (such as CdSe@ZnS core-shell structure quantum dots), and then perform ligand exchange on the CdSe@ZnS core-shell structure quantum dots with oleic acid as the ligand to form a new first ligand on the surface of the CdSe@ZnS core-shell structure quantum dots (QD) Finally, disperse it in an ether ester solvent such as propylene glycol monomethyl ether acetate at a concentration of 20 g / L, add a tetraepoxy crosslinking agent ( concentration of 1 g / L) and a photoacid generator (X-DBN, concentration of 0.5 g / L), spin-coat to form a film, under a photomask, irradiate with an ultraviolet lamp for 2 minutes, and the irradiation dose is 10 J / cm 2 , and a click chemical reaction occurs between the mercapto group of the first ligand in the exposed area and the epoxy group of the crosslinking agent to form a crosslinked network. The reaction formula for forming the crosslinked network is as Figure 1 shown. Finally, develop with propylene glycol monomethyl ether acetate to remove the quantum dots in the non-exposed area, dry to remove the solvent, and obtain a patterned quantum dot layer in the exposed area.

[0077] Taking the first crosslinking structure of the first ligand in the quantum dot ink as a mercapto group and the second crosslinking structure of the crosslinking agent as a carbon-carbon double bond as an example, the method for patterning the quantum dot layer will be described. Among them, the first ligand on the surface of the quantum dot is a polythiol (structure ), the crosslinking agent is a poly-double bond (structure ), the photoacid generator is 2-(2-nitrophenyl)propoxycarbonyl diethylamine (NPPOC-dea), and the solvent is propylene glycol monomethyl ether acetate.

[0078] First, synthesize quantum dot materials with oleic acid as the ligand (such as CdSe@ZnS core-shell quantum dots), and then perform ligand exchange on the CdSe@ZnS core-shell quantum dots with oleic acid as the ligand to form a new first ligand on the surface of the CdSe@ZnS core-shell quantum dots (QD). Finally, disperse it in ether ester solvents such as propylene glycol methyl ether acetate at a concentration of 20 g / L, add a tetra-double bond crosslinking agent ( at a concentration of 1 g / L) and a photoacid generator (NPPOC-dea, at a concentration of 0.5 g / L), spin-coat to form a film, and under a photomask template, irradiate with an ultraviolet lamp for 2 minutes, and the irradiation dose is 10 J / cm 2 . The thiol group of the first ligand in the exposed area undergoes a click chemical reaction with the carbon-carbon double bond of the crosslinking agent to form a crosslinked network. The reaction formula for forming the crosslinked network is as Figure 2 shown. Finally, develop with propylene glycol methyl ether acetate to remove the quantum dots in the non-exposed area, dry to remove the solvent, and obtain a patterned quantum dot layer in the exposed area.

[0079] It should be noted that the first crosslinking group of the first ligand is a thiol group, and the second crosslinking structure of the crosslinking agent is a carbon-carbon triple bond, an epoxy group or an isocyanate group. The process of realizing the patterning of the quantum dot layer by the principle of click chemical reaction is similar to the process of realizing the patterning of the quantum dot layer by the principle of click chemical reaction between the thiol group and the epoxy group or the carbon-carbon double bond, and will not be elaborated here.

[0080] It should be noted that in the embodiments of the present disclosure, the method for patterning quantum dots is described by taking the first crosslinking group of the first ligand as a thiol group and the second crosslinking structure of the crosslinking agent as an epoxy group, a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group or an isocyanate group as an example; of course, it is also possible to obtain the first crosslinking group of the first ligand as an epoxy group, a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group or an isocyanate group through ligand exchange, and the second crosslinking structure of the crosslinking agent is a thiol group to achieve a click chemical reaction and form a patterned quantum dot layer.

[0081] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the photo base generator is configured to generate a second ligand under illumination (such as ultraviolet light irradiation exposure), and the polarity of the second ligand is opposite to that of the first ligand; the second ligand includes a basic group containing a lone pair of electrons, and the basic group is configured to coordinate with the surface of the quantum dot so that the second ligand displaces the first ligand. In this way, when forming a patterned quantum dot layer, exposure is carried out under the shielding of a mask. By using the photo base generator to generate a second ligand with a polarity opposite to that of the first ligand on the surface of the original quantum dot after illumination, the second ligand can displace the first ligand, thereby causing a change in the solubility of the quantum dot material. Using the original good solvent as the developer, the quantum dot material in the unexposed area is washed away by the original solvent, and the surface of the quantum dot in the exposed area is retained due to the second ligand with a polarity opposite to that of the first ligand, thus forming a patterned quantum dot layer in the exposed area. Moreover, the quantum dot ink provided by this embodiment can achieve patterning of the quantum dot layer without adding a crosslinking agent.

[0082] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the basic group can be an amino group (-NH 2 ). The amino group with a lone pair of electrons can easily displace the first ligand on the surface of the quantum dot, thereby realizing a change in the solubility of the quantum dot material.

[0083] The principle of the photo base generator generating a second ligand with an amino group to guide quantum dot lithography patterning after illumination is as Figure 3 shown. After the photo base generator (PBG) is illuminated (UV), a nitrogen atom amine containing a lone pair of electrons is generated. The amine can form a bond with the surface atoms of the quantum dot (QD) and replace the original first ligand ( represented). Therefore, by changing the polarity of the molecule of the newly coordinated amine (the second ligand, represented), the solubility of the quantum dot material can be changed, thereby achieving the purpose of selective patterning.

[0084] In specific implementation, in order to make the solubility of the quantum dot material in the exposed area differ greatly from that of the quantum dot material in the unexposed area, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the polarity of the first ligand can be weakly polar, and the polarity of the second ligand is strongly polar; or, the polarity of the first ligand can be strongly polar, and the polarity of the second ligand is weakly polar.

[0085] In specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the first ligand includes: a coordination group that coordinates with the quantum dot, and a first polar group connected to the coordination group; the second ligand further includes a second polar group connected to the basic group; wherein,

[0086] One of the first polar group and the second polar group includes an alkyl chain segment or a polyether chain segment and a hydrocarbon group with a carbon chain length greater than 10 carbon atoms, and the other of the first polar group and the second polar group includes at least one of sulfonic acid, carboxyl group, nitroso group, cyano group, hydroxyl group, amide group, phenolic hydroxyl group, mercapto group, amino group and a hydrocarbon group with a carbon chain length less than 10 carbon atoms. In this way, the molecular polarity of the first ligand should be opposite to that of the photoacid generator, so that the second ligand generated by the photoacid generator under light irradiation can displace the first ligand, thereby changing the solubility of the quantum dot material and realizing the patterning of the quantum dot layer.

[0087] In a specific implementation, in the above-mentioned quantum dot ink provided by the embodiments of the present disclosure, the general structural formula of the photoacid generator is: Wherein, R1 and R2 are respectively an alkyl chain, an alkene chain, and contain at least one of phenyl, ester group, carbonyl group, and ether bond. Under ultraviolet light irradiation, -NH 2 Coordinates with the surface of the quantum dot and displaces the original first ligand on the surface of the quantum dot.

[0088] Optionally, R1 and R2 can be benzyl N-methylcarbamate, methyl N-methylcarbamate, benzyl N-ethylcarbamate, methyl N-ethylcarbamate, etc.

[0089] Taking the first ligand on the surface of the quantum dots in the quantum dot ink as oleic acid ( represented), the photoacid generator is N-carbobenzoxy-glycine and the solvent is toluene, the quantum dot layer patterning method will be described.

[0090] First, synthesize a quantum dot material with oleic acid as the ligand (such as CdSe@ZnS core-shell structure quantum dots), with a concentration of 20 g / L, add N-carbobenzoxy-glycine photoacid generator, spin-coat into a film, and under a photomask, irradiate with an ultraviolet lamp for 2 minutes, and the irradiation dose is 10 J / cm 2 , the photoacid generator in the exposed area generates a second ligand displaces the first ligand (oleic acid), thereby changing the solubility of the quantum dot material. The reaction formula for the second ligand to displace the first ligand is as Figure 4 shown. Finally, develop with toluene to remove the quantum dots in the non-exposed area, dry to remove the solvent, and obtain a patterned quantum dot layer in the exposed area.

[0091] It should be noted that Figures 1 - 4 only one or several first ligands are schematically shown on the surface of the quantum dots as shown, and of course, there can be multiple first ligands on the surface of the quantum dots.

[0092] Based on the same inventive concept, the embodiments of the present disclosure also provide a quantum dot layer patterning method, as Figure 5 shown, including:

[0093] S501. Form a quantum dot thin film using the above-mentioned quantum dot ink provided by the embodiments of the present disclosure;

[0094] S502. Under the shielding of a photomask, expose the quantum dot thin film to light. The first ligand of the quantum dot material in the exposed area changes under the action of light and a photoacid generator, and the solubility of the quantum dot material changes;

[0095] S503. Use a developer to wash away the quantum dots in the unexposed area to obtain a patterned quantum dot layer.

[0096] In the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure, due to the action of light (such as ultraviolet light exposure) and a photoacid generator, the first ligand on the surface of the quantum dots changes to change the solubility of the quantum dot material. In this way, the solubility of the quantum dot material in the exposed area is different from that in the unexposed area, so that a suitable developer can be selected to wash away the quantum dots in the unexposed area and form a patterned quantum dot layer in the exposed area.

[0097] In specific implementation, in the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure, when the first ligand of the quantum dot material in the exposed area changes under the action of light and a photoacid generator, it can specifically be:

[0098] The first crosslinking group of the first ligand in the exposed area and the second crosslinking group of the crosslinking agent undergo a crosslinking reaction under the action of the base generated by the photoacid generator. For this embodiment, reference can be made to the embodiment in which the above-mentioned quantum dot ink includes a quantum dot material, a photoacid generator, and a crosslinking agent. The reaction formula corresponding to the patterning principle can be seen in Figure 1 and Figure 2 , which will not be elaborated here.

[0099] In specific implementation, in the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure, when the first ligand of the quantum dot material in the exposed area changes under the action of light and a photoacid generator, it can specifically be:

[0100] The basic group of the second ligand generated by the photoacid generator in the exposed area coordinates with the surface of the quantum dots to replace the first ligand with the second ligand. For this embodiment, reference can be made to the embodiment in which the above-mentioned quantum dot ink includes a quantum dot material and a photoacid generator (generating a second ligand under light). The reaction formula corresponding to the patterning principle can be seen in Figure 3 and Figure 4 , which will not be elaborated here.

[0101] To achieve full-color display, the quantum dot layer generally includes patterned quantum dots of different colors. For example, the quantum dot layer includes a first quantum dot layer, a second quantum dot layer, and a third quantum dot layer. When using the first type of quantum dot ink provided by the embodiments of the present disclosure (including quantum dot materials, photoacid generators, and crosslinking agents), first, for example, prepare a first quantum dot material, a second quantum dot material, and a third quantum dot material with oleic acid as the surface ligand. Then, replace the oleic acid ligand of each quantum dot material with a new first ligand (e.g., ), add a photoacid generator and a crosslinking agent to each quantum dot material solution, and then use the above steps S501-S503 to fabricate a patterned first quantum dot layer; then repeat steps S501-S503 to obtain a patterned second quantum dot layer; then repeat steps S501-S503 to obtain a patterned third quantum dot layer. When using the second type of quantum dot ink provided by the embodiments of the present disclosure (including quantum dot materials and photoacid generators), first, for example, prepare a first quantum dot material, a second quantum dot material, and a third quantum dot material with oleic acid as the surface ligand, add a photoacid generator (which can generate a second ligand under light irradiation) to each quantum dot material solution, and then use the above steps S501-S503 to fabricate a patterned first quantum dot layer; then repeat steps S501-S503 to obtain a patterned second quantum dot layer; then repeat steps S501-S503 to obtain a patterned third quantum dot layer.

[0102] In specific implementation, the colors of the light emitted by the first quantum dot layer, the second quantum dot layer, and the third quantum dot layer in the embodiments of the present disclosure are red, green, and blue respectively. In this way, the embodiments of the present disclosure complete the patterning process of full-color quantum dots through the above patterning method. The embodiments of the present disclosure can complete the patterning of the quantum dot layer without using inkjet printing, and can form quantum dots with high resolution and good performance.

[0103] It should be noted that in the process of fabricating the first quantum dot layer, the second quantum dot layer, and the third quantum dot layer that emit light of different colors, the same photoacid generator or different photoacid generators can be selected.

[0104] In a possible implementation, for fabricating the above-mentioned first quantum dot layer, second quantum dot layer, and third quantum dot layer provided by the embodiments of the present disclosure, ultraviolet light of the same wavelength can be used to irradiate the reserved regions of the first quantum dot layer, the second quantum dot layer, and the third quantum dot layer. Of course, light of the H line can also be used to irradiate the reserved region of the first quantum dot layer to form the first quantum dot layer that emits red light, and the wavelength of the H line is 405 nm; light of the I line can be used to irradiate the reserved region of the second quantum dot layer to form the second quantum dot layer that emits green light, and the wavelength of the I line is 365 nm; light of the G line can be used to irradiate the reserved region of the third quantum dot layer to form the third quantum dot layer that emits blue light, and the wavelength of the G line is 436 nm.

[0105] In specific implementation, the quantum dot layer fabricated by the embodiments of the present disclosure can not only be used as the light-emitting layer in a QLED device, but also as the light conversion film layer in the backlight of a liquid crystal display screen, the color filter layer in a liquid crystal display screen, the color filter layer in a white OLED device + color filter layer, and so on.

[0106] Based on the same inventive concept, the embodiments of the present disclosure also provide a quantum dot layer, which includes a plurality of patterned sub-pixels, and each sub-pixel includes a quantum dot material. The quantum dot material includes quantum dots and a crosslinked network connected to the surface of the quantum dots. The crosslinked network includes at least one of the following structures:

[0107] For the above-mentioned quantum dot layer provided by the embodiments of the present disclosure, the crosslinked network on the surface of the quantum dots can be obtained by the click chemical reaction of a thiol group with a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, or an isocyanate group under the catalysis of a base. Thus, the crosslinking reaction is carried out by using a ligand containing a thiol group and a crosslinking agent containing a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, or an isocyanate group under the action of a photoacid generator and light irradiation, or by using a crosslinking agent containing a thiol group and a ligand containing a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, or an isocyanate group under the action of a photoacid generator and light irradiation to realize the patterning of the quantum dot layer. The process of obtaining the quantum dot layer of this embodiment can refer to the relevant descriptions of the content of the first quantum dot ink and the quantum dot layer patterning method described above, and will not be elaborated here.

[0108] Optionally, in the above-mentioned quantum dot layer provided by the embodiments of the present disclosure, the structure of the crosslinked network can be

[0109]

[0110] (See the relevant description of Figure 1 ) and

[0111]

[0112] (See the relevant description of Figure 2 ) and

[0113] (Crosslinking product of mercapto group and carbon-carbon triple bond) or

[0114] (Crosslinking product of mercapto group and isocyanate).

[0115] It should be noted that the above four crosslinking networks are only several crosslinking network structures exemplified in the present disclosure, and of course are not limited thereto.

[0116] Based on the same inventive concept, the embodiments of the present disclosure further provide a quantum dot layer, including a plurality of patterned sub-pixels, each sub-pixel including a quantum dot material, the quantum dot material including quantum dots and a first ligand and a second ligand connected to the surface of the quantum dots, the polarity of the second ligand being opposite to that of the first ligand, and the second ligand including a basic group containing a lone pair of electrons.

[0117] For the above quantum dot layer provided by the embodiments of the present disclosure, the second ligand on the surface of the quantum dots can be a ligand generated by a photoacid generator under light illumination. The polarity of the second ligand is opposite to that of the first ligand. In this way, under light illumination, the second ligand can displace the first ligand, changing the solubility of the original quantum dot material and realizing the patterning of the quantum dot layer. The process of obtaining the quantum dot layer of this embodiment can refer to the relevant descriptions of the above-mentioned second quantum dot ink and the quantum dot layer patterning method, and will not be elaborated here.

[0118] In specific implementation, in the above quantum dot layer provided by the embodiments of the present disclosure, the general structural formula of the second ligand can be: (See the relevant description in Figure 4 ); where R1 is at least one of an alkyl chain, an alkene chain, a phenyl group, an ester group, a carbonyl group, and an ether bond.

[0119] In specific implementation, in the above quantum dot layer provided by the embodiments of the present disclosure, the first ligand can be oleic acid, oleylamine, etc.

[0120] Based on the same inventive concept, the embodiments of the present disclosure further provide a quantum dot light-emitting device, including the above quantum dot layer provided by the embodiments of the present disclosure.

[0121] Optionally, the quantum dot light-emitting device provided by the present disclosure can be a quantum dot light-emitting diode, a photodetector, a photovoltaic solar cell, etc., but is not limited thereto.

[0122] Optionally, in addition to having the quantum dot layer of the present disclosure, the quantum dot light-emitting device provided by the present disclosure can also have the structure of a conventional optoelectronic device.

[0123] Optionally, the quantum dot light-emitting device provided by the present disclosure may be a quantum dot light-emitting diode. In addition to having the quantum dot layer of the present disclosure, the quantum dot light-emitting diode may further include an anode, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a cathode, a packaging layer, etc., but is not limited thereto.

[0124] Specifically, for the anode, hole injection layer, hole transport layer, electron transport layer, electron injection layer, cathode, packaging layer, etc. of the quantum dot light-emitting diode according to the embodiments of the present disclosure, the specific structure, material composition, and preparation method may adopt any suitable structure, material composition, and preparation method without special limitations.

[0125] Optionally, the quantum dot light-emitting diode provided by the embodiments of the present disclosure may be configured as a single-sided light-emitting quantum dot device and a double-sided light-emitting quantum dot device, or may be configured as a top light-emitting type, a bottom light-emitting type, and a double-sided light-emitting type.

[0126] Based on the same inventive concept, the embodiments of the present disclosure further provide a method for manufacturing a quantum dot light-emitting device, including forming a quantum dot layer by using the above-mentioned quantum dot layer patterning method provided by the embodiments of the present disclosure.

[0127] To further understand the present disclosure, the following will describe in detail the method for manufacturing the quantum dot light-emitting device of the present disclosure with reference to embodiments.

[0128] The quantum dot light-emitting device (such as a quantum dot light-emitting diode) prepared in this embodiment may include: an anode, a hole injection layer, a hole transport layer, red, green, and blue quantum dot layers, an electron transport layer, an electron injection layer, a cathode, and a packaging layer. The preparation method is as follows:

[0129] (1) As Figure 6A shown, an anode 2, a hole injection layer 3, and a hole transport layer 4 are sequentially formed on a substrate 1 in a stacked manner.

[0130] (2) As Figure 6B shown, a red quantum dot ink containing the first quantum dot material (red), a photoacid generator, and a crosslinking agent prepared above is coated on the hole transport layer 4 to form a red quantum dot thin film 5'; as Figure 6C shown, a first Photo Mask is added, and the red quantum dot thin film 5' is exposed to ultraviolet light (H line); as Figure 6D shown, development and fixation are performed to form a first quantum dot layer 5.

[0131] (3) As Figure 6E shown, a green quantum dot ink containing the second quantum dot material (green), a photoacid generator, and a crosslinking agent prepared above is coated on the first quantum dot layer 5 to form a green quantum dot thin film 6'; as Figure 6FAs shown, a second photomask is added, and ultraviolet light (I-line) is used to expose the green quantum dot film 6'; as Figure 6G shown, development and fixation are carried out to form the second quantum dot layer 6.

[0132] (4) As Figure 6H shown, the prepared blue quantum dot ink containing the third quantum dot material (blue), photoacid generator, and crosslinking agent is coated on the second quantum dot layer 6 to form a blue quantum dot film 7'; as Figure 6I shown, a third photomask is added, and ultraviolet light (G-line) is used to expose the blue quantum dot film 7'; as Figure 6J shown, development and fixation are carried out to form the third quantum dot layer 7.

[0133] (5) As Figure 6K shown, an electron transport layer 8 and an electron injection layer 9, such as ZnO nanoparticles, are sequentially spin-coated or evaporated on the film layers where the first quantum dot layer 5, the second quantum dot layer 6, and the third quantum dot layer 7 are located; as Figure 6L shown, then a cathode metal thin layer is evaporated to form a cathode 10. The cathode 10 can be an Al layer, etc., with a thickness of about 500 - 1000 nm. After evaporation, packaging and cutting are carried out to complete the fabrication of the quantum dot light-emitting device with a normal structure.

[0134] It should be noted that the embodiments of the present disclosure mainly take the light-emitting device with a normal structure as an example to describe the manufacturing method of the quantum dot light-emitting device in detail. Of course, the embodiments of the present disclosure are also applicable to the manufacturing of the quantum dot light-emitting device in an inverted structure. The structure of the quantum dot light-emitting device in the inverted structure is as Figure 7 shown. The manufacturing methods of the respective film layers in the inverted structure are the same as those of the respective film layers in the normal structure, and the difference lies only in the different sequences of film layer manufacturing.

[0135] Specifically, the substrate provided by the embodiments of the present disclosure may include a substrate, a driving circuit located on the substrate, and structures such as a passivation layer and a planarization layer located above the driving circuit.

[0136] The light extraction mode of the above-mentioned light-emitting device formed by the embodiments of the present disclosure can be bottom light extraction or top light extraction.

[0137] Based on the same inventive concept, embodiments of the present disclosure further provide a display device, including the above-mentioned quantum dot light-emitting device provided by the embodiments of the present disclosure. The principle of the display device for solving problems is similar to that of the aforementioned quantum dot light-emitting device. Therefore, the implementation of the display device can refer to the implementation of the aforementioned quantum dot light-emitting device, and the repeated parts will not be elaborated here. The display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, etc. Other essential components of the display device are understood by those of ordinary skill in the art and will not be elaborated here, nor should they be regarded as a limitation of the present invention.

[0138] A quantum dot ink, a method for patterning a quantum dot layer, and a quantum dot light-emitting device provided by embodiments of the present disclosure. When using the quantum dot ink of the present disclosure to fabricate a patterned quantum dot layer, due to the action of light (such as ultraviolet light exposure) and a photoacid generator, the first ligand on the surface of the quantum dots changes to alter the solubility of the quantum dot material. In this way, the solubility of the quantum dot material in the exposed area is different from that in the non-exposed area, so that a suitable developer can be selected to wash away the quantum dots in the non-exposed area, and a patterned quantum dot layer is formed in the exposed area. Therefore, the quantum dot ink provided by the embodiments of the present disclosure can directly form a patterned quantum dot layer through a photolithography process, avoiding the technical difficulty of using an inkjet printing process that requires a higher-precision print head to improve the resolution in the related art. The present disclosure can effectively realize the production of high-resolution QLED products.

[0139] Obviously, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure also intends to include these modifications and variations.

Claims

1. A quantum dot ink, wherein: The invention comprises a quantum dot material and a photobase generator, wherein the quantum dot material comprises quantum dots and a first ligand connected to the surface of the quantum dots, and the quantum dot material is configured such that under the action of light and the photobase generator, the first ligand on the surface of the quantum dots changes to change the solubility of the quantum dot material.

2. The quantum dot ink according to claim 1, wherein: The quantum dot ink also includes a crosslinking agent, the first ligand includes a first crosslinking group, the crosslinking agent includes a second crosslinking group, one of the first crosslinking group and the second crosslinking group is a thiol, and the other of the first crosslinking group and the second crosslinking group is a group that can undergo a crosslinking reaction with the thiol and the photobase generator under light.

3. The quantum dot ink according to claim 2, wherein: The other of the first cross-linking group and the second cross-linking group includes at least one of a carbon-carbon double bond, a carbon-carbon triple bond, an epoxy group, and an isocyanate group.

4. The quantum dot ink according to claim 3, wherein: The cross-linking agent includes at least two of the second cross-linking groups.

5. The quantum dot ink according to claim 4, wherein: The crosslinking agent also includes a solubility regulating structure connected to the second crosslinking group.

6. The quantum dot ink according to claim 5, wherein: The solubility regulating structure includes at least one weak polar group and a hydrocarbon group having a carbon chain length greater than or equal to 10 carbon atoms, or the solubility regulating structure includes at least one strong polar group and a hydrocarbon group having a carbon chain length less than 10 carbon atoms.

7. The quantum dot ink according to claim 6, wherein: The weak polar groups include methyl, phenyl or aldehyde groups, and the strong polar groups include sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, thiol or amino groups.

8. The quantum dot ink according to any one of claims 2 to 7, wherein: The first ligand further includes: a connecting group connected to the first cross-linking group, and a coordination group connected to the connecting group; the coordination group is configured to coordinate with the quantum dot.

9. The quantum dot ink according to claim 8, wherein: The coordination group includes at least one of -NH2, -SH, -COOH, -P, and -P=O.

10. The quantum dot ink according to claim 8, wherein: The connecting group is an alkyl segment or a polyether segment.

11. The quantum dot ink according to claim 10, wherein: The alkyl segment has at least one double bond or benzene ring group, or the alkyl segment is a straight chain alkyl containing 1C-30C; The polyether segment includes polyethylene oxide.

12. The quantum dot ink according to any one of claims 2 to 11, wherein: The photobase generator includes at least one of cobalt amine complex, quaternary ammonium salt, carbamate, oxime ester, amidine, guanidine, -amino ketone, polynitrogen heterocycle, and tetraphenylborate.

13. The quantum dot ink according to claim 1, wherein: The photobase generator is configured to generate a second ligand under light, and the polarity of the second ligand is opposite to that of the first ligand; the second ligand includes a basic group containing a lone pair of electrons, and the basic group is configured to coordinate with the surface of the quantum dot so that the second ligand replaces the first ligand.

14. The quantum dot ink according to claim 13, wherein: The basic group is an amino group.

15. The quantum dot ink according to claim 13, wherein: The polarity of the first ligand is weak polarity, and the polarity of the second ligand is strong polarity; or the polarity of the first ligand is strong polarity, and the polarity of the second ligand is weak polarity.

16. The quantum dot ink according to claim 15, wherein: The first ligand includes: a coordination group that coordinates with the quantum dot, and a first polar group connected to the coordination group; the second ligand also includes a second polar group connected to the basic group; wherein, One of the first polar group and the second polar group includes an alkyl segment or a polyether segment and a hydrocarbon group with a carbon chain length greater than 10 carbon atoms, and the other of the first polar group and the second polar group includes at least one of sulfonic acid, carboxyl, nitroso, cyano, hydroxyl, amide, phenolic hydroxyl, thiol, and amino, and a hydrocarbon group with a carbon chain length less than 10 carbon atoms.

17. The quantum dot ink according to any one of claims 13 to 16, wherein: The general structural formula of the photobase generator is: Among them, R1 and R2 are at least one of an alkyl chain, an olefin chain, a phenyl group, an ester, a carbonyl group, and an ether bond.

18. A method for patterning a quantum dot layer, wherein: include: Forming a quantum dot film using the quantum dot ink according to any one of claims 1 to 17; Under the cover of the mask, the quantum dot film is exposed to light, and the first ligand of the quantum dot material in the exposed area changes under the action of light and the photobase generator, and the solubility of the quantum dot material changes; The quantum dots in the unexposed area are removed by washing with a developer to obtain a patterned quantum dot layer.

19. The method for patterning a quantum dot layer according to claim 18, wherein: The quantum dot material in the exposed area undergoes a change in the first ligand under the action of light and the photobase generator, specifically: The first cross-linking group of the first ligand in the exposed area and the second cross-linking group of the cross-linking agent undergo a cross-linking reaction under the action of the base generated by the photobase generator.

20. The method for patterning a quantum dot layer according to claim 18, wherein: The quantum dot material in the exposed area undergoes a change in the first ligand under the action of light and the photobase generator, specifically: The basic group of the second ligand generated by the photobase generator in the exposed area is coordinated and combined with the surface of the quantum dot, so that the second ligand replaces the first ligand.

21. A quantum dot layer, wherein: The invention comprises a plurality of patterned sub-pixels, each of which comprises a quantum dot material, wherein the quantum dot material comprises a quantum dot and a cross-linked network connected to the surface of the quantum dot, wherein the cross-linked network comprises at least one of the following structures:

22. The quantum dot layer of claim 21, wherein: The structure of the cross-linked network is 23. A quantum dot layer, wherein: It includes a plurality of patterned sub-pixels, each of which includes a quantum dot material, the quantum dot material includes a quantum dot and a first ligand and a second ligand connected to the surface of the quantum dot, the polarity of the second ligand is opposite to the polarity of the first ligand, and the second ligand includes a basic group containing a lone pair of electrons.

24. The quantum dot layer of claim 23, wherein: The general structural formula of the second ligand is: Among them, R1 is at least one of an alkyl chain, an olefin chain, a phenyl group, an ester, a carbonyl group, and an ether bond.

25. A quantum dot light-emitting device, wherein: Comprising a quantum dot layer as described in any one of claims 21-24.

26. A method for manufacturing a quantum dot light-emitting device, wherein: It comprises forming a quantum dot layer by using the quantum dot layer patterning method as described in any one of claims 18 to 20.

27. A display device, wherein: Comprising the quantum dot light-emitting device as described in claim 25.

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