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

Abstract

The invention provides a quantum dot material system, a quantum dot layer patterning method and a quantum dot light-emitting device.The quantum dot material system comprises a first cross-linked structure and a second cross-linked structure, one of the first cross-linked structure and the second cross-linked structure is a tetrazole group, and the other of the first cross-linked structure and the second cross-linked structure is a tetrazole group. The other of the first cross-linked structure and the second cross-linked structure is an alkenyl group.

Description

Quantum dot material system, quantum dot layer patterning method and quantum dot light-emitting device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a quantum dot material system, a quantum dot layer patterning method, 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 Group III-V elements. They typically range in size from 1 to 20 nm. Due to the quantum confinement of electrons and holes, the continuous energy band structure is transformed into a discrete energy level structure, allowing them to emit fluorescence upon stimulation.

[0003] 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 production efficiency of QLEDs has not yet reached the level of mass production. The most important reason is that there has not yet been a breakthrough in high-resolution patterning technology for QLEDs. The inorganic nanoparticle characteristics of quantum dots make it difficult to form films and pattern them through evaporation, and it is difficult to achieve high resolution through inkjet printing.

[0004] Summary of the Invention

[0005] The present disclosure provides a quantum dot material system, a quantum dot layer patterning method, and a quantum dot light-emitting device. The specific solutions are as follows:

[0006] An embodiment of the present disclosure provides a quantum dot material system, which includes a first cross-linking structure and a second cross-linking structure, wherein one of the first cross-linking structure and the second cross-linking structure is a tetrazole group, and the other of the first cross-linking structure and the second cross-linking structure is an alkenyl group.

[0007] Optionally, in the above-mentioned quantum dot material system provided in the embodiment of the present disclosure, the quantum dot material system includes a first quantum dot material and a second quantum dot material, the first quantum dot material includes a first quantum dot and a first ligand connected to the surface of the first quantum dot, the first ligand includes the first cross-linking structure, the second quantum dot material includes a second quantum dot and a second ligand connected to the surface of the second quantum dot, and the second ligand includes the second cross-linking structure.

[0008] Optionally, in the above-mentioned quantum dot material system provided in the embodiment of the present disclosure, the quantum dot material system includes a third quantum dot material, the third quantum dot material includes a third quantum dot and a first ligand and a second ligand connected to the surface of the third quantum dot, the first ligand includes the first cross-linking structure, and the second ligand includes the second cross-linking structure.

[0009] Optionally, in the above-mentioned quantum dot material system provided in the embodiment of the present disclosure, the quantum dot material system includes a first quantum dot material and a cross-linker, the first quantum dot material includes a first quantum dot and a first ligand connected to the surface of the first quantum dot, the first ligand includes the first cross-linking structure, and the cross-linker includes the second cross-linking structure.

[0010] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the cross-linking agent includes at least two second cross-linking structures.

[0011] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the second cross-linking structure is a tetrazole group, and the carbon atoms of each tetrazole group are connected by a first connecting structure; or, the second cross-linking structure is an alkenyl group, and the carbon atoms adjacent to each alkenyl group are connected by a second connecting structure;

[0012] Wherein, the first connecting structure and the second connecting structure are respectively flexible segments or rigid segments.

[0013] Optionally, in the quantum dot material system provided in the embodiment of the present disclosure, the flexible segment includes an alkyl chain,

[0014] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the rigid segment includes a functional group having hole transport or electron transport, or the rigid segment includes a conjugated group capable of transporting holes and electrons.

[0015] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the rigid segment includes at least one of triphenylamine, carbazole, and fluorene.

[0016] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the alkenyl group includes acrylate, methacrylate or a double bond containing a substituent.

[0017] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the tetrazole group has no substituent or has a substituent.

[0018] Optionally, in the above quantum dot material system provided by the embodiment of the present disclosure, each ligand further comprises: a linking group connected to the cross-linking structure, and a coordination group connected to the linking group;

[0019] The coordination group is configured to coordinate with the corresponding quantum dot.

[0020] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the coordination group includes at least one of an amino group, a carboxylic acid group, a thiol group, a dithiol group, a phosphine group, and a phosphineoxy group.

[0021] Optionally, in the quantum dot material system provided in the embodiment of the present disclosure, the connecting group is (CH2) n , n = 2 to 8;

[0022] Alternatively, the linking group is a linear or branched alkyl chain.

[0023] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, each ligand further includes a carrier transport regulating group connected between the connecting group and the cross-linking structure.

[0024] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the carrier transport regulating group includes at least one of triphenylamine, aniline, carbazole, imidazole, and fluorene.

[0025] Accordingly, the present disclosure also provides a method for patterning a quantum dot layer, comprising:

[0026] Forming a quantum dot film using the quantum dot material system provided in the embodiments of the present disclosure;

[0027] Under the cover of a mask, the quantum dot film is exposed to light of a preset wavelength, so that the tetrazole groups and alkenyl groups in the exposed area undergo a cross-linking reaction;

[0028] The quantum dots in the unexposed area are washed away with a developer to obtain a patterned quantum dot layer.

[0029] Accordingly, an embodiment of the present disclosure further provides a quantum dot layer comprising a plurality of patterned sub-pixels, each of which comprises a quantum dot material, the quantum dot material comprising quantum dots and a cross-linked network connected to the surface of the quantum dots, the cross-linked network comprising at least the following structure:

[0030] Optionally, in the quantum dot layer provided in the embodiment of the present disclosure, the structure of the cross-linked network is

[0031] Correspondingly, the embodiments of the present disclosure further provide a quantum dot light-emitting device, comprising the above-mentioned quantum dot layer provided by the embodiments of the present disclosure.

[0032] Correspondingly, the embodiments of the present disclosure further provide a method for manufacturing a quantum dot light-emitting device, comprising forming a quantum dot layer using the above-mentioned quantum dot layer patterning method provided in the embodiments of the present disclosure.

[0033] Correspondingly, an embodiment of the present disclosure further provides a display device, comprising the above-mentioned quantum dot light-emitting device provided by an embodiment of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic diagram of the reaction mechanism of the cross-linking reaction between tetrazole groups and alkenyl groups under light irradiation (hv);

[0035] FIG2 is a non-schematic diagram of a cross-linking reaction between a quantum dot material and a cross-linking agent provided in an embodiment of the present disclosure;

[0036] FIG3 is a non-schematic diagram of a cross-linking reaction between another quantum dot material and a cross-linking agent provided by an embodiment of the present disclosure;

[0037] FIG4 is a non-schematic diagram of a cross-linking reaction between another quantum dot material and a cross-linking agent provided by an embodiment of the present disclosure;

[0038] FIG5 is a non-schematic diagram of a cross-linking reaction between another quantum dot material and a cross-linking agent provided by an embodiment of the present disclosure;

[0039] FIG6 is a schematic diagram of a process of a quantum dot layer patterning method provided in an embodiment of the present disclosure;

[0040] 7A-7C are schematic diagrams of the structure of the quantum dot layer after each step is performed;

[0041] 8A-8K are schematic diagrams of the structure of the quantum dot light-emitting device after each step is performed. DETAILED DESCRIPTION

[0042] In order to make the purpose, 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 in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. And in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0043] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words “include” or “comprise” and the like used in this disclosure mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words “connect” or “connected” and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Inside”, “outside”, “upper”, “lower”, etc. 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.

[0044] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual scale and are only for the purpose of illustrating the present disclosure. The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0045] An embodiment of the present disclosure provides a quantum dot material system, which includes a first cross-linking structure and a second cross-linking structure, one of the first cross-linking structure and the second cross-linking structure is a tetrazole group, and the other of the first cross-linking structure and the second cross-linking structure is an alkenyl (double bond) group.

[0046] The tetrazole group and alkenyl group in the quantum dot material system provided by the embodiment of the present disclosure have photosensitive properties. When the quantum dot material system of the present disclosure is used to make a patterned quantum dot layer, the tetrazole group and alkenyl group can undergo a cross-linking reaction under light (such as ultraviolet light exposure), thereby achieving the purpose of cross-linking the quantum dots. Then, the uncross-linked quantum dots are removed by elution with a suitable developer, and finally a patterned quantum dot layer is obtained. Therefore, the quantum dot material system 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 a higher-precision print head to improve the resolution in the related art using an inkjet printing process. The present disclosure can effectively achieve high-resolution QLED product production, facilitate process preparation, improve process yield, and significantly increase the utilization rate of quantum dot materials, thereby paving the way for large-scale QLED industrialization.

[0047] It should be noted that the quantum dot material system provided in the embodiments of the present disclosure is not only suitable for making the light-emitting layer of electroluminescent QLED devices (i.e., the light-emitting layer between the cathode and anode), but is also suitable for making photoluminescent layers (e.g., a white light OLED + color filter layer structure). That is, the patterned quantum dot layer produced using the quantum dot material system provided in the embodiments of the present disclosure can be used as the color filter layer in the white light OLED + color filter layer. Of course, this is not limited to this, and it can also be used as the light-emitting layer in a light source, for example.

[0048] Specifically, the reaction mechanism of the cross-linking reaction between the tetrazole group and the alkenyl group under light (hv) is shown in Figure 1, wherein R1 can be a substituent such as phenyl, alkyl, etc., R2 can be a substituent such as phenyl, alkyl, etc., and R3 can be a substituent such as alkyl, Ar, etc. The tetrazole group is exposed to light to form a nitrile imine, and then reacts with the double bond 1,3-dipole cycloaddition to form a five-membered ring. In this way, when forming a patterned quantum dot layer, under the shielding of the mask, the first cross-linking structure and the second cross-linking structure in the exposed area undergo a cross-linking reaction to form a cross-linked network, thereby changing the solubility of the quantum dots in the exposed area. A suitable developer is used for elution treatment to remove the quantum dots in the unexposed area, and finally a patterned quantum dot layer is obtained.

[0049] In a specific implementation, in the quantum dot material system provided in the embodiments of the present disclosure, the quantum dot material system includes a first quantum dot material and a second quantum dot material, the first quantum dot material includes a first quantum dot and a first ligand connected to the surface of the first quantum dot, the first ligand including a first cross-linking structure, and the second quantum dot material includes a second quantum dot and a second ligand connected to the surface of the second quantum dot, the second ligand including a second cross-linking structure. Thus, when patterning the quantum dot layer, the quantum dot material system is applied and exposed to light, and the first cross-linking structure of the first ligand in the exposed area and the second cross-linking structure of the second ligand undergo a cross-linking reaction, i.e., a cross-linking network is formed between the first quantum dot and the second quantum dot, thereby changing the solubility of the quantum dots in the exposed area. A suitable developer is then used for elution treatment to remove the quantum dots in the unexposed area, ultimately resulting in a patterned quantum dot layer.

[0050] Optionally, for example, the structure of the first quantum dot material is The structure of the second quantum dot material is The principle of cross-linking reaction between the two under light (hv) is as follows:

[0051] The above is only an example of the structure of the first quantum dot material and the second quantum dot material, and is of course not limited to this. As long as one of the first cross-linking structure of the first ligand and the second cross-linking structure of the second ligand is a tetrazole group and the other is an alkenyl (double bond) group.

[0052] In a specific implementation, in the quantum dot material system provided in the embodiments of the present disclosure, the quantum dot material system includes a third quantum dot material, the third quantum dot material includes a third quantum dot and a first ligand and a second ligand connected to the surface of the third quantum dot, the first ligand includes a first cross-linked structure, and the second ligand includes a second cross-linked structure. Thus, when patterning the quantum dot layer, the quantum dot material system is applied and exposed to light, and the first cross-linked structure of the first ligand and the second cross-linked structure of the second ligand in the exposed area undergo a cross-linking reaction, i.e., a cross-linked network is formed between the first cross-linked structure and the second cross-linked structure of the third quantum dot itself and the third quantum dot, thereby changing the solubility of the quantum dot in the exposed area. A suitable developer is then used for elution treatment to remove the quantum dots in the unexposed area, ultimately obtaining a patterned quantum dot layer.

[0053] Optionally, for example, the structure of the third quantum dot material is For example, the first ligand is The second ligand is The principle of the cross-linking reaction between the first ligand and the second ligand under light irradiation (hv) is as follows:

[0054] The above is only an example of the structure of the third quantum dot material, and is of course not limited thereto, as long as one of the first cross-linking structure of the first ligand and the second cross-linking structure of the second ligand is a tetrazole group and the other is an alkenyl (double bond) group.

[0055] It should be noted that the above in It represents ABC introduced later, where A is the corresponding coordination group (anchor group), B is the corresponding connecting group, and C is the carrier transport regulating group.

[0056] In a specific implementation, the quantum dot material system provided in the embodiments of the present disclosure includes a first quantum dot material and a crosslinker. The first quantum dot material includes a first quantum dot and a first ligand attached to the surface of the first quantum dot. The first ligand includes a first crosslinking structure, and the crosslinker includes a second crosslinking structure. Thus, when forming a patterned quantum dot layer, under the protection of a mask, the first crosslinking structure of the first ligand in the exposed area and the second crosslinking structure of the crosslinker undergo a crosslinking reaction to form a crosslinked network, thereby changing the solubility of the quantum dots in the exposed area. A suitable developer is then used to remove the quantum dots in the unexposed area, ultimately resulting in a patterned quantum dot layer.

[0057] In a specific implementation, in order to improve the stability of the cross-linked quantum dots, in the quantum dot material system provided in the embodiment of the present disclosure, the cross-linking agent includes at least two second cross-linking structures. Optionally, when the second cross-linking structure of the cross-linking agent is a tetrazole group, the cross-linking agent structure including two tetrazole groups can be The cross-linker structure including three tetrazole groups can be Of course, the cross-linking agent may also include four or more tetrazole groups; when the second cross-linking structure of the cross-linking agent is an alkenyl group, the cross-linking agent structure including two alkenyl groups may be The cross-linker structure comprising three alkenyl groups may be Of course, the crosslinking agent may also include four or even more alkenyl groups.

[0058] In specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, when the first cross-linking structure is an alkenyl group, the ligand structure of the quantum dot material can be When the first cross-linking structure is a tetrazole group, the ligand structure of the quantum dot material can be in, The left end is used to coordinate with the quantum dot surface.

[0059] In a specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, the first cross-linking structure is an alkenyl group, the second cross-linking structure is a tetrazole group, and the carbon atoms of each tetrazole group in the cross-linking agent are connected by the first connecting structure. For example, a cross-linking agent including two tetrazole groups (structured as ), wherein the carbon atom of one tetrazole group is connected to the carbon atom of another tetrazole group via a first connecting structure ( ) connected, including three tetrazole groups of the cross-linking agent (structure ), wherein the carbon atoms of the three tetrazole groups are connected by a first connecting structure ( indicates) connection.

[0060] Optionally, the first connecting structure may be a flexible segment or a rigid segment.

[0061] In a specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, the first cross-linking structure is a tetrazole group, the second cross-linking structure is an alkenyl group, and the carbon atoms adjacent to each alkenyl group in the cross-linking agent are connected by the second connecting structure; for example, a cross-linking agent including two alkenyl groups (structured as ), the carbon atom adjacent to one alkenyl group and the carbon atom adjacent to the other alkenyl group are connected by a second connecting structure ( ) connected, including three alkenyl groups of cross-linking agent (structure ), with the carbon atoms adjacent to each alkenyl group being connected by a second connecting structure ( indicates) connection.

[0062] Optionally, the second connecting structure may be a flexible segment or a rigid segment.

[0063] In specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, the flexible segment may include but is not limited to an alkyl chain, (This structure represents the aforementioned first connection structure or second connection structure ), (This structure represents the aforementioned first connection structure or second connection structure ), (This structure represents the aforementioned first connection structure or second connection structure ), (This structure represents the aforementioned first connection structure or second connection structure )or

[0064] It should be noted that, in the above structural formulas It means that the above-mentioned soft segment is further connected to the carbon atom of the alkenyl group or the tetrazole group in the cross-linking agent.

[0065] In specific implementations, in the quantum dot material system provided in the embodiments of the present disclosure, the rigid segments may include functional groups capable of hole or electron transport, or the rigid segments may include conjugated groups capable of hole and electron transport. Thus, when a patterned quantum dot layer formed using the quantum dot material system provided in the embodiments of the present disclosure is used as a quantum dot layer in an electroluminescent device, it is beneficial to improve the carrier transport efficiency of the electroluminescent device, thereby improving the efficiency of the electroluminescent device.

[0066] Optionally, in the quantum dot material system provided in the embodiments of the present disclosure, the rigid segment may include, but is not limited to, at least one of triphenylamine, carbazole, and fluorene, wherein triphenylamine and carbazole are conducive to hole transport, and fluorene is conducive to hole and electron transport.

[0067] In specific implementations, in the quantum dot material systems provided in the embodiments of the present disclosure, the alkenyl group may include, but is not limited to, acrylate, methacrylate, or a double bond containing a substituent. For example, when the alkenyl group is a ligand structure of the quantum dot material, the embodiments of the present disclosure use the ligand's alkenyl group as an example of methacrylate, although this is not limiting. When the alkenyl group is a crosslinker structure, the embodiments of the present disclosure use the crosslinker's alkenyl group as an example of acrylate, although this is not limiting.

[0068] In specific implementation, in the above-mentioned quantum dot material system provided in the embodiment of the present disclosure, the tetrazole group has no substituent or has a substituent. For example, in the embodiment of the present disclosure, whether the first cross-linking structure of the ligand is a tetrazole group or the second cross-linking structure of the cross-linking agent is a tetrazole group, the present disclosure is based on the tetrazole group having a substituent (for example, the substituent is a benzene ring) as an example, and the absorption wavelength and absorbance are adjusted by adding a substituent to the tetrazole group, thereby improving the sensitivity of the quantum dot material system to light. Optionally, the substituent on the tetrazole group can be a conjugated group, such as a benzene ring, benzophenone, aniline, thiophene, bithiophene, etc. The principle is that the conjugated group determines the absorption wavelength, and after absorbing photons, the energy is transferred to the tetrazole group for a photochemical reaction.

[0069] In a specific implementation, in the quantum dot material system provided in the embodiments of the present disclosure, when the quantum dot material system includes a first quantum dot material and a second quantum dot material, the first ligand further includes: a first linking group connected to the first cross-linking structure, and a first coordination group connected to the first linking group; the first coordination group is configured to coordinate with the first quantum dot; the second ligand further includes: a second linking group connected to the second cross-linking structure, and a second coordination group connected to the second linking group; the second coordination group is configured to coordinate with the second quantum dot. For example, the general structural formula of each ligand is ABD, wherein A is the corresponding coordination group (anchor group), B is the corresponding linking group, and D is the corresponding cross-linking structure (tetrazolyl group or alkenyl group).

[0070] In a specific implementation, in the quantum dot material system provided in the embodiments of the present disclosure, when the quantum dot material system includes a third quantum dot material, the first ligand further includes: a first linking group connected to the first cross-linking structure, and a first coordination group connected to the first linking group; the first coordination group is configured to coordinate with the third quantum dot; the second ligand further includes: a second linking group connected to the second cross-linking structure, and a second coordination group connected to the second linking group; the second coordination group is configured to coordinate with the third quantum dot. For example, the general structural formula of each ligand is ABD, wherein A is the corresponding coordination group (anchor group), B is the corresponding linking group, and D is the corresponding cross-linking structure (tetrazolyl group or alkenyl group).

[0071] In a specific implementation, in the quantum dot material system provided in the embodiments of the present disclosure, when the quantum dot material system includes a first quantum dot material and a crosslinker, the first ligand further includes: a first linking group connected to the first crosslinking structure, and a first coordination group connected to the first linking group; the first coordination group is configured to coordinate with the first quantum dot. For example, the first ligand has the general structural formula ABD, where A is the first coordination group (anchor group), B is the first linking group, and D is the first crosslinking structure (tetrazolyl group or alkenyl group).

[0072] In specific implementation, in the above-mentioned quantum dot material system provided in the embodiment of the present disclosure, each coordination group (first coordination group and second coordination group) may include but is not limited to at least one of amino group, carboxylic acid group, thiol group, dithiol group, phosphine group, and phosphineoxy group.

[0073] In a specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, each linking group (the first linking group and the second linking group) can be -(CH2) n -, n = 2 to 8; specifically, selecting a linking group with a carbon chain length of 2 to 8 can prevent the ligand from being affected by excessive steric hindrance and affecting the preparation of the ligand, and a carbon chain that is too long will affect the injection of charges;

[0074] Alternatively, each linking group (the first linking group and the second linking group) is a linear or branched alkyl chain.

[0075] In practice, to improve the carrier transport efficiency of the quantum dot layer formed using the quantum dot material system of the present disclosure, each ligand in the quantum dot material system provided in the embodiments of the present disclosure may further include a carrier transport modulating group connected between the linking group and the crosslinking structure. For example, the general structural formula of each ligand is ABCD, where A is the corresponding coordination group (anchor group), B is the corresponding linking group, C is the carrier transport modulating group, and D is the corresponding crosslinking structure (tetrazolyl group or alkenyl group).

[0076] In specific implementation, in the quantum dot material system provided in the embodiment of the present disclosure, the carrier transport regulating group may include but is not limited to at least one of triphenylamine, aniline, carbazole, imidazole, and fluorene. Specifically, the ligand of the quantum dot material in means ABC, Indicates D.

[0077] In specific implementation, in the above-mentioned quantum dot material system provided in the embodiments of the present disclosure, quantum dots may include but are not limited to CdS, CdSe, ZnSe, InP, PbS, CsPbCl3, CsPbBr3, CsPbI3, CdS / ZnS, CdSe / ZnS, CdSe / ZnSe, InP / ZnS, PbS / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPhI3 / ZnS, ZnTeSe / ZnSe and other quantum dots and at least one of nanoparticle materials such as ZnO, ZnMgO, ZnAlO, and ZnLiO.

[0078] Furthermore, to facilitate mixing and coating, the quantum dot material system of the disclosed embodiments may further include a solvent. Prior to exposure, the solvent is a good solvent for the quantum dot material. After exposure, the cross-linked quantum dot network is insoluble in the solvent. Specifically, the solvent can be selected based on the polarity of the ligands in the quantum dot material.

[0079] Specifically, the ligand structure of quantum dot materials is The structure of the crosslinker is For example, the reaction process of the quantum dot material system undergoing cross-linking reaction under light (hv) is shown in FIG2 ; Optionally, the ligand of the quantum dot material in FIG2 can be etc., wherein n=1-4, R=-H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3 or -CH2CH2CH2CH2CH3, and the cross-linking agent can be Where n = 1 to 2,

[0080] It should be noted that the above R Indicates the carbon atom of the benzene ring at this position The N atoms in the .

[0081] Specifically, the structure of the cross-linking agent is For example, the reaction principle for synthesizing the cross-linking agent can be The specific synthesis process of the cross-linking agent is as follows: 0.16g 4-(1H-tetrazol-5-yl)benzoic acid (0.6mmol) and 37.5mg tetraethylene glycol (0.25mmol) are dissolved in 8mL dichloromethane (DCM), and argon is passed for 30 minutes to remove oxygen. 0.248g DCC (dicyclohexylcarbodiimide, 1.2mmol) and 7.33mg DMAP (4-dimethylaminopyridine, 0.06mmol) are added to the above solution and stirred overnight at room temperature under argon protection. The above reaction mixture is precipitated with ether / tetrahydrofuran (10:1v / v) mixed solvent, filtered and vacuum dried. Specifically, the ligand structure of the quantum dot material is The structure of the crosslinker is For example, the reaction process of the quantum dot material system undergoing cross-linking reaction under light (hv) is shown in FIG3 ; Optionally, the ligand of the quantum dot material in FIG3 can be etc., the cross-linking agent can be n=1~2,

[0082] It should be noted that the above R Indicates the carbon atom of the benzene ring at this position Specifically, the structure of the cross-linking agent is For example, the reaction principle for synthesizing the cross-linking agent can be

[0083] The crosslinker was synthesized as follows: 0.16 g of 4-(1H-tetrazol-5-yl)benzoic acid (0.6 mmol) and 125 mg of 4-Arm-PEG-500 (0.025 mmol) were dissolved in 8 mL of dichloromethane (DCM) and deoxygenated by purging with argon for 30 minutes. 0.248 g of DCC (dicyclohexylcarbodiimide, 1.2 mmol) and 7.33 mg of DMAP (4-dimethylaminopyridine, 0.06 mmol) were added to the solution and stirred overnight at room temperature under argon. The reaction mixture was precipitated with a 10:1 v / v mixture of diethyl ether and tetrahydrofuran, filtered, and dried under vacuum.

[0084] Specifically, the ligand structure of quantum dot materials is The structure of the crosslinker is For example, the reaction process of the quantum dot material system undergoing cross-linking reaction under light (hv) is shown in FIG4 ; Optionally, the ligand of the quantum dot material in FIG4 can be in The crosslinking agent can be n=1-2.

[0085] It should be noted that the above Each Indicates the carbon atom of the benzene ring at this position The N atoms in the .

[0086] Specifically, the ligand structure of quantum dot materials is The structure of the crosslinker is For example, the reaction process of the quantum dot material system undergoing cross-linking reaction under light (hv) is shown in FIG5 ; optionally, the ligand of the quantum dot material in FIG5 can be in The crosslinking agent can be n=1-2.

[0087] It should be noted that the above Each Indicates the carbon atom of the benzene ring at this position The N atoms in the .

[0088] Specifically, as shown in Figures 2 to 5, Represents quantum dots.

[0089] It should be noted that Figures 2 to 5 are only examples of the cross-linking reaction of several ligands and cross-linkers under light irradiation illustrated in the present disclosure. Of course, it is not limited to this. As long as one of the ligand and the cross-linker includes a tetrazole group and the other includes an alkenyl group, it is protected by the present disclosure.

[0090] Based on the same inventive concept, the present disclosure also provides a method for patterning a quantum dot layer, as shown in FIG6 , comprising:

[0091] S601, forming a quantum dot film using the quantum dot material system provided by the embodiments of the present disclosure;

[0092] S602, exposing the quantum dot film to light of a preset wavelength under the protection of a mask, so that the tetrazole groups and alkenyl groups in the exposed area undergo a cross-linking reaction;

[0093] S603 , using a developer to elute and remove the quantum dots in the unexposed area to obtain a patterned quantum dot layer.

[0094] Taking the quantum dot material system including the first quantum dot material and the cross-linking agent as an example, the quantum dot layer patterning method disclosed in the present invention is described in detail:

[0095] (1) First, a first quantum dot material is prepared. The first quantum dot material includes a first quantum dot (e.g., CdSe / ZnSe), and the surface of the first quantum dot has a first ligand (e.g., ); dissolving the first quantum dot material in n-octane or PGMEA solvent to disperse into a 30 mg / mL solution; adding the crosslinking agent shown in FIG. 2 (eg ), the mass fraction of the cross-linking agent is 1%-5%. Red, green and blue quantum dot material systems are prepared respectively.

[0096] (2) As shown in FIG7A , a quantum dot film 2′ is formed on a substrate 1 (e.g., a driving backplane) using the quantum dot material system (e.g., green) formed as described above; there is no particular limitation on the method for forming the quantum dot film 2′, and any suitable film-forming method may be used, such as spin coating, screen printing, blade coating, drop coating, dip coating, Langmuir–Blodgett deposition, etc.

[0097] (3) As shown in FIG7B , under the shielding of a mask 3 having an exposed region 31 and an unexposed region 32, the quantum dot film 2' is exposed to ultraviolet light 4 (e.g., I-ray, 365 nm). The intensity of the ultraviolet light 4 can be determined as needed. The tetrazole groups and alkenyl groups in the exposed region 31 undergo a cross-linking reaction to form a cross-linked network, thereby changing the solubility of the quantum dots in the exposed region 31. The cross-linking reaction process can be seen in FIG2 .

[0098] (4) As shown in FIG7C , a developer (PGMEA or toluene) is used for elution treatment to remove the quantum dots in the unexposed area 32 , and the substrate 1 is heated at 90° C. for 120 s to remove the developer, thereby finally obtaining a patterned green quantum dot layer 2 .

[0099] Afterwards, the above steps (1)-(4) are repeated to form a patterned blue quantum dot layer and a red quantum dot layer, thereby achieving full-color patterning of the red, green, and blue quantum dot layers.

[0100] Optionally, the quantum dot layer patterning method of the embodiment of the present disclosure may further include steps such as baking and vacuum drying as needed, but is not limited thereto.

[0101] Based on the same inventive concept, the present disclosure also provides a quantum dot layer comprising a plurality of patterned sub-pixels, each sub-pixel comprising a quantum dot material, the quantum dot material comprising quantum dots and a cross-linked network connected to the surface of the quantum dots, the cross-linked network comprising at least the following structure:

[0102] It should be noted that in Indicates each The location is also connected to other structures.

[0103] Specifically, It is a partial structure in a cross-linked network formed by a cross-linking reaction between the first quantum dot material (the first ligand has a first cross-linked structure) and the cross-linking agent (having a second cross-linked structure) provided by the present disclosure under ultraviolet light irradiation.

[0104] In specific implementation, in the quantum dot layer provided in the embodiment of the present disclosure, the structure of the cross-linked network can be (See the reaction process shown in Figure 2), (See the reaction process shown in Figure 3), (See the reaction process shown in Figure 4) (See the reaction process shown in Figure 5).

[0105] It should be noted that the above Carbonyl-linked Represents the ABC structure of the quantum dot surface ligand, between the two tetrazole groups It represents the rigid segment or flexible segment mentioned above.

[0106] It should be noted that the above Carbonyl-linked Represents the ABC structure of the quantum dot surface ligand, between the three tetrazole groups It represents the rigid segment or flexible segment mentioned above.

[0107] It should be noted that the above Tetrazolyl groups are connected Represents the ABC structure of the quantum dot surface ligand, between the two carbonyl groups It represents the rigid segment or flexible segment mentioned above.

[0108] It should be noted that the above Tetrazolyl groups are connected Represents the ABC structure of the quantum dot surface ligand, the three carbonyl groups It represents the rigid segment or flexible segment mentioned above.

[0109] It should be noted that the above four cross-linked networks are merely examples of the cross-linked network structures described in this disclosure and are certainly not limited thereto.

[0110] In specific implementation, the quantum dot layer provided in the embodiment of the present disclosure is prepared using the quantum dot layer patterning method disclosed above.

[0111] Based on the same inventive concept, the embodiments of the present disclosure further provide a quantum dot light-emitting device, comprising the above-mentioned quantum dot layer provided by the embodiments of the present disclosure.

[0112] Optionally, the quantum dot light-emitting device provided in the present disclosure may be a quantum dot light-emitting diode, a photodetector, a photovoltaic solar cell, etc., but is not limited thereto.

[0113] Optionally, the quantum dot light-emitting device provided by the present disclosure may have the structure of a conventional optoelectronic device in addition to the quantum dot layer of the present disclosure.

[0114] Alternatively, the quantum dot light-emitting device provided by the present disclosure may be a quantum dot light-emitting diode. In addition to the quantum dot layer disclosed herein, 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, an encapsulation layer, etc., but is not limited thereto.

[0115] Specifically, the specific structure, material composition and preparation method of the anode, hole injection layer, hole transport layer, electron transport layer, electron injection layer, cathode, encapsulation layer, etc. of the quantum dot light-emitting diode according to the embodiment of the present disclosure can adopt any suitable structure, material composition and preparation method without special restrictions.

[0116] Optionally, the quantum dot light-emitting diode provided in the embodiment of the present disclosure can be configured as a single-sided light-emitting quantum dot device and a double-sided light-emitting quantum dot device, or configured as a top-emitting type, a bottom-emitting type, and a double-sided light-emitting type.

[0117] 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 using the above-mentioned quantum dot layer patterning method provided in the embodiments of the present disclosure.

[0118] In order to further understand the present disclosure, the method for manufacturing the quantum dot light-emitting device of the present disclosure is described in detail below with reference to the embodiments.

[0119] The quantum dot light-emitting device (e.g., quantum dot light-emitting diode) prepared in this embodiment may include: a driving backplane, an anode, a hole injection layer, a hole transport layer, a red, green, and blue quantum dot layer, an electron transport layer, an electron injection layer, a cathode, an encapsulation layer, and an upper polarizer. The preparation method is as follows:

[0120] (1) As shown in FIG8A, the substrate 11 is cleaned.

[0121] (2) As shown in FIG8B , a gate metal material (e.g., Mo, with a thickness of 200 nm) is sequentially deposited on the substrate 11 and patterned to form a gate; a gate insulating layer (e.g., SiO2, with a thickness of 150 nm) is formed on the gate; an active layer (e.g., IGZO, with a thickness of 40 nm) is formed on the gate insulating layer; a source and drain metal material (e.g., Mo, with a thickness of 200 nm) is deposited on the active layer and patterned to form a source and drain; a passivation layer (e.g., SiO2, with a thickness of 300 nm) is formed on the source and drain, an anode (e.g., ITO, with a thickness of 40 nm) is formed on the passivation layer, an acrylic material is spin-coated on the anode, and a pixel defining layer (with a thickness of approximately 1.5 μm) is photolithographically cured to form a driving backplane (substrate 1); the surface of the driving backplane is then treated with plasma, and a hole injection layer and a hole transport layer 10 are prepared by spin coating, such as spin coating PEDOT:PSS and TFB, etc.; the overall thickness thereof is 50-100 nm.

[0122] (3) As shown in FIG8C , the green quantum dot material system prepared above is coated on the hole transport layer 10 to form a green quantum dot film 2 ′; as shown in FIG8D , a first photo mask is added, and the green quantum dot film 2 ′ is exposed to ultraviolet light (I line); as shown in FIG8E , development and fixing are performed to form a green quantum dot layer 2.

[0123] (4) As shown in FIG8F , the above-prepared blue quantum dot material system is coated on the green quantum dot layer 2 to form a blue quantum dot film 5 ′; as shown in FIG8G , a second photo mask is added, and the blue quantum dot film 5 ′ is exposed to ultraviolet light (G line); as shown in FIG8H , development and fixing are performed to form a blue quantum dot layer 5 .

[0124] (5) As shown in FIG8I , the prepared red quantum dot material system is coated on the blue quantum dot layer 5 to form a red quantum dot film 6 ′. As shown in FIG8J , a third photo mask is added, and the red quantum dot film 6 ′ is exposed to ultraviolet light (H line). As shown in FIG8K , the red quantum dot layer 6 is formed by developing and fixing.

[0125] (6) Spin coating or vapor deposition of an electron transport layer and an electron injection layer, such as ZnO nanoparticles, on the film layer where the green quantum dot layer 2, the blue quantum dot layer 5, and the red quantum dot layer 6 are located; then vapor deposition of a cathode metal thin layer to form a cathode, the cathode can be an Al layer, etc., with a thickness of about 500-1000nm. After the vapor deposition is completed, the device is packaged and cut to complete the production of a quantum dot light-emitting device with an upright structure.

[0126] Optionally, the light emission mode of the quantum dot light emitting device can be bottom emission, and the minimum area of ​​the sub-pixel that can be prepared is 10μm-30μm, about 300-800ppi.

[0127] It should be noted that the embodiments of the present disclosure mainly use the light-emitting device in an upright structure as an example to explain in detail the method for manufacturing a quantum dot light-emitting device. Of course, the embodiments of the present disclosure are also applicable to the manufacture of quantum dot light-emitting devices in an inverted structure.

[0128] Based on the same inventive concept, the embodiments of the present disclosure further provide a display device, including the above-mentioned quantum dot light-emitting device provided in the embodiments of the present disclosure. The principle of solving the problem of the display device 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 repeated here. The display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, navigator, etc. The other essential components of the display device should be understood by ordinary technicians in this field, and will not be repeated here, nor should they be used to limit the present invention.

[0129] The embodiments of the present disclosure provide a quantum dot material system, a method for patterning a quantum dot layer, and a quantum dot light-emitting device. The tetrazole group and the alkenyl group in the quantum dot material system have photosensitivity. When the quantum dot material system of the present disclosure is used to make a patterned quantum dot layer, the tetrazole group and the alkenyl group can undergo a cross-linking reaction under light (e.g., ultraviolet light exposure) to achieve the purpose of cross-linking the quantum dots. The uncross-linked quantum dots are then removed by elution with a suitable developer, and a patterned quantum dot layer is finally obtained. Therefore, the quantum dot material system 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 a higher-precision print head to improve the resolution in the related art using an inkjet printing process. The present disclosure can effectively achieve high-resolution QLED product production, facilitate process preparation, improve process yield, and significantly increase the utilization rate of quantum dot materials, thereby paving the way for large-scale QLED industrialization.

[0130] Obviously, those skilled in the art may make various changes and modifications 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 equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A quantum dot material system, wherein, the quantum dot material system includes a first crosslinked structure and a second crosslinked structure, one of the first crosslinked structure and the second crosslinked structure is a tetrazole group, and the other of the first crosslinked structure and the second crosslinked structure is an alkenyl group.

2. The quantum dot material system according to claim 1, wherein, the quantum dot material system includes a first quantum dot material and a second quantum dot material. The first quantum dot material includes a first quantum dot and a first ligand connected to the surface of the first quantum dot, and the first ligand includes the first crosslinked structure. The second quantum dot material includes a second quantum dot and a second ligand connected to the surface of the second quantum dot, and the second ligand includes the second crosslinked structure.

3. The quantum dot material system according to claim 1, wherein, the quantum dot material system includes a third quantum dot material. The third quantum dot material includes a third quantum dot and a first ligand and a second ligand connected to the surface of the third quantum dot, the first ligand includes the first crosslinked structure, and the second ligand includes the second crosslinked structure.

4. The quantum dot material system according to claim 1, wherein, the quantum dot material system includes a first quantum dot material and a crosslinking agent. The first quantum dot material includes a first quantum dot and a first ligand connected to the surface of the first quantum dot, the first ligand includes the first crosslinked structure, and the crosslinking agent includes the second crosslinked structure.

5. The quantum dot material system according to claim 4, wherein, the crosslinking agent includes at least two of the second crosslinked structures.

6. The quantum dot material system according to claim 5, wherein, the second crosslinked structure is a tetrazole group, and the carbon atoms of each tetrazole group are connected through a first connecting structure; or, the second crosslinked structure is an alkenyl group, and the carbon atoms adjacent to each alkenyl group are connected through a second connecting structure; wherein the first connecting structure and the second connecting structure are respectively a flexible chain segment or a rigid chain segment.

7. The quantum dot material system according to claim 6, wherein, The flexible chain segment includes an alkyl chain, 8. The quantum dot material system according to claim 6, wherein, the rigid chain segment includes a functional group with hole transport or electron transport, or the rigid chain segment includes a conjugated group capable of transporting holes and electrons.

9. The quantum dot material system according to claim 8, wherein, the rigid chain segment includes at least one of triphenylamine, carbazole, and fluorene.

10. The quantum dot material system according to any one of claims 1-9, wherein, the alkenyl group includes acrylate, methacrylate, or a double bond with a substituent.

11. The quantum dot material system according to any one of claims 1-10, wherein, the tetrazole group has no substituent or has a substituent.

12. The quantum dot material system according to any one of claims 2-4, wherein, each ligand further includes: a connecting group connected to the crosslinked structure, and a coordinating group connected to the connecting group; the coordinating group is configured to coordinate and bind to the corresponding quantum dot.

13. The quantum dot material system according to claim 12, wherein, the coordination group includes at least one of amino group, carboxyl group, mercapto group, dimercapto group, phosphino group, and phosphinyloxy group.

14. The quantum dot material system according to claim 12, wherein, The linking group is (CH 2 ) n , where n = 2 to 8; alternatively, the linking group is a linear or branched alkyl chain.

15. The quantum dot material system according to any one of claims 12-14, wherein, each ligand further includes a carrier transport regulating group connected between the linking group and the crosslinked structure.

16. The quantum dot material system according to claim 15, wherein, the carrier transport regulating group includes at least one of triphenylamine, aniline, carbazole, imidazole, and fluorene.

17. A method for patterning a quantum dot layer, wherein, it includes: forming a quantum dot thin film by using the quantum dot material system according to any one of claims 1-16; under the shielding of a mask plate, exposing the quantum dot thin film under light irradiation with a preset wavelength, and a crosslinking reaction occurs between the tetrazole group and the alkenyl group in the exposed area; eluting and removing the quantum dots in the unexposed area by using a developer to obtain a patterned quantum dot layer.

18. A quantum dot layer, wherein, Comprising a plurality of patterned sub-pixels, each of the sub-pixels comprising a quantum dot material, the quantum dot material comprising quantum dots and a crosslinked network connected to the surface of the quantum dots, the crosslinked network at least comprising the following structure:

19. The quantum dot layer according to claim 18, wherein, The structure of the crosslinked network is 20. A quantum dot light-emitting device, wherein, it includes the quantum dot layer according to claim 18 or 19.

21. A manufacturing method of a quantum dot light-emitting device, wherein, it includes forming a quantum dot layer by using the method for patterning a quantum dot layer according to claim 17.

22. A display device, wherein, it includes the quantum dot light-emitting device according to claim 20.

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