Chemically modified graphene oxide, display device and method of manufacturing the same

Abstract

The application relates to the field of semiconductor display devices, in particular to chemically modified graphene oxide, a display device and a preparation method thereof. The chemically modified graphene oxide comprises a graphene oxide body and a graphene oxide ligand combined on the graphene oxide body, the graphene oxide body is provided with an oxygen-containing group, the graphene oxide ligand is combined on the oxygen-containing group, and the graphene oxide ligand can undergo a cross-linking reaction under light irradiation. After a quantum dot film layer is formed, a layer of photo-crosslinkable chemically modified graphene oxide is arranged on the quantum dot film layer, the chemically modified graphene oxide at the position of the corresponding exposure area is crosslinked after exposure in the corresponding area, a dense monomolecular protective layer is formed, quantum dots that need to be reserved can be protected from being destroyed or removed while eliminating quantum dot residues by using a strong developing agent, and the display device is prevented from being invalid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor display devices, in particular to chemically modified graphene oxide, display devices and preparation methods thereof. BACKGROUND

[0002] Semiconductor quantum dots are an important fluorescent nanomaterial. Quantum dots are used as light-emitting layer materials in the field of flat panel lighting and optoelectronic display, and are increasingly attracting attention from academia and industry. So far, the external quantum efficiency (EQE) of quantum dot light-emitting diodes (QLED) has reached more than 20% in terms of device performance. At the same time, semiconductor quantum dots can also be used as light conversion materials to convert blue or white light emitted by a light source into other colors.

[0003] Semiconductor quantum dots, whether as a light-emitting material or a light conversion material, need to be patterned in the device fabrication process. Compared with inkjet printing process, direct photolithography has higher resolution and better film morphology and thickness uniformity in the mass production of quantum dot patterning. However, in the process of quantum dot patterning by direct photolithography, quantum dots will remain in the pixel area, causing color mixing. In order to better remove the residues and ensure the color gamut, some strong developers / washing agents are usually used to remove the residues. However, this also easily leads to another problem, i.e., the removal effect is too strong, resulting in the quantum dots that are supposed to be left being washed away or partially damaged, leading to device failure. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a chemically modified graphene oxide. By introducing a cross-linkable ligand on the chemically modified graphene oxide, a dense protective film layer is formed on the surface of the quantum dot layer, which protects the quantum dots from being damaged or removed while using a strong developer to eliminate residues.

[0005] The purpose of the present application is also to provide a display device based on the chemically modified graphene oxide and a preparation method thereof.

[0006] As a first aspect of the present application, a chemically modified graphene oxide is provided. The chemically modified graphene oxide comprises a graphene oxide body and a graphene oxide ligand combined on the graphene oxide body. An oxygen-containing group is formed on the graphene oxide body, and the graphene oxide ligand is combined on the oxygen-containing group. The graphene oxide ligand can undergo a cross-linking reaction under light.

[0007] Optionally, the oxygen-containing group is at least one of an epoxy group, a hydroxyl group, a carboxyl group and a carbonyl group.

[0008] Optionally, the graphene oxide ligand comprises a first coordination group, a first linking group and a first cross-linking group connected in sequence by chemical bonds, the first coordination group binds with the oxygen-containing group, and the first cross-linking group is used for cross-linking reaction to occur under light.

[0009] Optionally, the first coordination group is an amino group, a polyamino group, a hydroxyl group, a polyhydroxyl group, a mercapto group, a polymercapto group, a sulfide group, a polysulfide group, a phosphine group or a phosphine oxide group.

[0010] Optionally, the first linking group is a methylene group, a C 2-8 a straight-chain alkyl chain, an alkyl chain containing a branched main chain of 2-8 C atoms, a tert-butylphenyl group, a methoxy group or a n-butoxy group.

[0011] Optionally, the first cross-linking group is a double bond group, a triple bond group, an epoxy group, an amino group, a hydroxyl group or a mercapto group.

[0012] Optionally, the double bond group is an olefin group, an ester group, an aldehyde group, a carbonyl group or an azido group.

[0013] Optionally, the triple bond group is an alkyne group or a cyano group.

[0014] Optionally, the epoxy group is an oxirane group, an oxetane group, a butylene oxide group or a pentylene oxide group.

[0015] Optionally, the graphene oxide ligand is selected from one of the following compounds:

[0016]

[0017] As a second aspect of the present application, a display device is provided, comprising a quantum dot film and a graphene oxide film formed on the surface of the quantum dot film, the graphene oxide film comprising the chemically modified graphene oxide of the first aspect of the present application, and the chemically modified graphene oxides are cross-linked and combined by the graphene oxide ligands.

[0018] Optionally, the graphene oxide film is provided with a plurality of graphene oxide films, and each is arranged one-to-one with a sub-pixel of different colors of the display device, and the cross-linking degree of the graphene oxide ligands in the same graphene oxide film is greater than the cross-linking degree of the graphene oxide ligands between adjacent graphene oxide films.

[0019] Optionally, the display device is a QLED electroluminescent device, and the quantum dot film is used as a quantum dot light-emitting layer of the QLED electroluminescent device.

[0020] Optionally, the quantum dot film comprises a quantum dot body and a quantum dot ligand bound to the quantum dot body, and the quantum dot ligand is cross-linked and combined with the graphene oxide ligand.

[0021] Optionally, the display device further comprises an electron transport layer disposed adjacent to the quantum dot light emitting layer, the electron transport layer comprising zinc oxide and a zinc oxide ligand bound to the zinc oxide, the quantum dot ligand being cross-linked to the zinc oxide ligand.

[0022] Optionally, the display device comprises an electroluminescent device, the quantum dot film and the graphene oxide film disposed in sequence, the quantum dot film serving as a light conversion layer of the display device.

[0023] Optionally, the electroluminescent device is an OLED or a Micro LED.

[0024] Optionally, the electroluminescent device is a blue light source, and the quantum dot film comprises a red light conversion quantum dot film and a green light conversion quantum dot film.

[0025] Optionally, the electroluminescent device is a white light source, and the quantum dot film comprises a red light conversion quantum dot film, a green light conversion quantum dot film and a blue light conversion quantum dot film.

[0026] As a third aspect of the present application, a preparation method of a display device is provided, in which the preparation method of the display device comprises:

[0027] coating a quantum dot solution to form a quantum dot film;

[0028] spin-coating the chemically modified graphene oxide of the first aspect of the present application on the quantum dot film;

[0029] exposing a preset region of the quantum dot film according to the patterning requirement, so that in the exposed region, the chemically modified graphene oxide is cross-linked to form a dense graphene oxide film;

[0030] developing, so that outside the exposed region, the chemically modified graphene oxide and the quantum dot film are removed.

[0031] Compared with a conventional quantum dot film layer, the present application sets a layer of photo-cross-linkable chemically modified graphene oxide on the quantum dot film layer after forming the quantum dot film layer. After exposure in the corresponding region, the chemically modified graphene oxide at the position of the corresponding exposed region is cross-linked to form a dense monomolecular protective layer. While using a strong developing agent to remove the quantum dots, the quantum dots that need to be retained can be protected from being damaged or removed, thereby avoiding the failure of the display device. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and together with the following detailed description, serve to explain the present application, but do not constitute a limitation on the present application;

[0033] Figure 1 A schematic diagram of a chemical reaction in which graphene oxide is modified by 3-butene-1-amine is shown;

[0034] Figure 2 A schematic diagram of a chemical reaction in which graphene oxide is modified by but-3-yn-1-amine is shown;

[0035] Figure 3 A schematic diagram of a chemical reaction in which graphene oxide is modified by allylamine is shown;

[0036] Figure 4 A schematic diagram of a structure of a quantum dot modified by a quantum dot ligand is shown;

[0037] Figure 5 A schematic diagram of a cross-linking structure formed by chemically modified graphene oxide and quantum dots modified by a quantum dot ligand is shown;

[0038] Figure 6 A schematic diagram of a modified structure formed by zinc oxide nanoparticles and a zinc oxide ligand is shown;

[0039] Figure 7 A schematic diagram of a modified structure formed by a sol-gel prepared zinc oxide film and a zinc oxide ligand is shown;

[0040] Figure 8 A process flow diagram of a quantum dot light-emitting layer structure in a QLED electroluminescent device is shown;

[0041] Figure 9 A process flow diagram of a light conversion structure in a BOLED-QD full-color display device is shown;

[0042] Figure 10 A process flow diagram of a light conversion structure in a WOLED-QD full-color display device is shown; and

[0043] Figure 11 A process flow diagram of a light conversion structure in a Micro LED-QD full-color display device is shown. DETAILED DESCRIPTION

[0044] The application discloses a quantum dot ligand, a quantum dot and a quantum dot film, a QLED light-emitting device and a preparation method thereof. Those skilled in the art can refer to the content herein and appropriately improve process parameters to realize. It should be particularly pointed out that all similar replacements and changes are obvious to those skilled in the art, and they are all regarded as included in the application. The products, processes and applications described in the application have been described by preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the products, processes and applications described herein without departing from the content, spirit and scope of the application, to realize and apply the technology of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0045] It should be noted that, in this document, relational terms such as "first" and "second", "S1 and S2", "step 1" and "step 2", and "(1)" and "(2)" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Meanwhile, the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0046] In the perspective of actual industrial mass production, the photolithography is usually adopted to realize the patterning of electronic materials (quantum dots). The photolithography needs to be assisted by photoresist. The photoresist includes positive photoresist and negative photoresist. However, the photoresist process has some problems in application: the negative photoresist has a lower cost, but the developer usually adopts p-xylene, and the benzene-based organic solvent is toxic and is not conducive to environmental protection. The positive photoresist has a good contrast, so that the generated pattern has a good resolution; and the developer is an alkaline aqueous solution, which is conducive to environmental protection. However, the alkali solution can damage the quantum dots of the light-emitting layer. Specifically, the quantum dot patterning is realized based on the "lift-off" process of the positive photoresist, and the main steps are: "deposition of photoresist- mask exposure of target area-development-deposition of quantum dots-full exposure-development-introduction of patterned quantum dot layer in target area". If a full-color (red, green, and blue) QLED device is prepared, the above steps need to be repeated three times. Among them, the development of the photoresist is mainly assisted by an alkaline solution (such as an ammonia solution or a tetramethylammonium hydroxide aqueous solution). Unfortunately, the alkaline solution can seriously damage the surface ligand state of the quantum dots, which is specifically manifested that the hydroxide ions in the alkali solution can destroy the coordination between the surface ligand and the nanocrystal dangling bond, thereby exposing the surface defect sites of the quantum dots again, finally damaging the light-emitting layer and reducing the device efficiency. Therefore, developing a more friendly development process or a more environmentally friendly patterning process to prepare high-resolution full-color QLED has become the focus and difficulty of quantum dot display process research.

[0047] Based on this, in a first aspect of the present application, a chemically modified graphene oxide is provided, which includes a graphene oxide body and a graphene oxide ligand combined on the graphene oxide body, an oxygen-containing group is formed on the graphene oxide body, the graphene oxide ligand is combined on the oxygen-containing group, and the graphene oxide ligand can undergo cross-linking reaction under light. Compared with conventional quantum dot film layers, the present embodiment can set a layer of photo-crosslinkable chemically modified graphene oxide on the quantum dot film layer after forming the quantum dot film layer. After exposure in the corresponding area, the chemically modified graphene oxide at the position of the corresponding exposed area is crosslinked to form a dense monomolecular protective layer. While eliminating the quantum dot residues using a strong developer, the quantum dots can be protected from being damaged or removed, thereby avoiding the failure of the display device.

[0048] The structure of graphene oxide is shown in formula (1):

[0049]

[0050] Graphene oxide is an important derivative of graphene. Like graphene, graphene oxide has a sheet structure, but unlike graphene, the carbon atoms in graphene oxide are not all composed of sp2 hybridized carbon atoms, but some exist in the form of sp3 hybridization. These sp3 hybridized carbon atoms are connected to oxygen-containing functional groups while being bonded to another three carbon atoms. These oxygen-containing groups include, but are not limited to, at least one of an epoxy group, a hydroxyl group, a carboxyl group, and a carbonyl group. Their introduction not only does not destroy the sheet structure of graphene, but also increases the reactive active sites in the graphene sheet and at the edges, making graphene oxide more easily chemically modified than graphene.

[0051] Optionally, the graphene oxide ligand has an A-B-C structure, wherein A is a first coordination group that binds to the oxygen-containing group on the graphene oxide body, B is a first linking group that connects A and C, and C is a first cross-linking group for cross-linking, the first coordination group A, the first linking group B, and the first cross-linking group C are sequentially connected by a chemical bond, and the first cross-linking group is used for cross-linking reaction under light.

[0052] A, B, and C groups are optionally connected by an alkyl chain or directly connected by a chemical bond.

[0053] Optionally, the first coordination group A is an amino group, a polyamino group, a hydroxyl group, a polyhydroxyl group, a mercapto group, a polysulfhydryl group, a sulfide group, a polysulfide group, a phosphine group, or a phosphine oxide group.

[0054] Optionally, the first linking group is a methylene group, a straight-chain alkyl chain of C 2-8 , an alkyl chain containing 2-8 C atoms of a branched main chain, a tert-butyl phenyl group, a methoxy group, or a n-butoxy group. In some embodiments of the present application, the first linking group is a straight-chain alkyl chain of C2, C3, C4, C5, C6, C7, such as 1,2-ethylene, butane chain, pentane chain, hexane chain, and heptane chain.

[0055] Optionally, the first cross-linking group is a double bond group, a triple bond group, an epoxy group, an amino group, a hydroxyl group, or a mercapto group. In some embodiments of the present application, the double bond group is an olefin group, an ester group, an aldehyde group, a carbonyl group, or an azide group; in some embodiments of the present application, the triple bond group is an alkyne group or a cyano group; in some embodiments of the present application, the epoxy group is an oxirane group, an oxetane group, an oxetane group, or an oxetane group.

[0056] In some embodiments of the present application, the graphene oxide ligand can be 3-butene-1-amine shown in formula (2), but-3-yn-1-amine shown in formula (3), or allylamine shown in formula (4). The schematic diagram of the reaction of graphene oxide with 3-butene-1-amine shown in formula (2) is shown in FIG. 1. Figure 2, the reaction of graphene oxide with but-3-yn-1-amine shown in formula (3) is shown in reference Figure 3 , the reaction of graphene oxide with allylamine shown in formula (4) is shown in reference Figure 1 .

[0057]

[0058] Due to the introduction of oxygen-containing groups on graphene oxide, the reactive active sites in the graphene oxide layer and the edge are increased, so that the graphene oxide is more easily chemically modified, and can be combined with the first coordination group structure in the graphene oxide ligand. The preparation method of the chemically modified graphene oxide formed by the combination of the graphene oxide bulk and the graphene oxide ligand is applicable to the prior art, and the present application is not limited. For example, when the graphene oxide ligand is selected as 3-but-1-ene-1-amine shown in formula (2), but-3-yn-1-amine shown in formula (3), or allylamine shown in formula (4), an optional exemplary preparation method is as follows: 10mg-50mg of graphene oxide ligand is added to 5ml of 10mg / ml graphene oxide bulk, and the reaction is carried out at 60°C in a water bath for 10-30min, so that the graphene oxide ligand is modified on the graphene oxide bulk. In the above preparation method, the first coordination group in the graphene oxide ligand can react with the carboxyl group on the graphene oxide bulk, so that the cross-linkable triple bond or double bond is modified on the graphene oxide bulk.

[0059] In the second aspect of the present application, a display device is provided, and the display device has a graphene oxide film formed by the aforementioned chemically modified graphene oxide. Specifically, the display device includes a quantum dot film and a graphene oxide film formed on the surface of the quantum dot film, the graphene oxide film includes the aforementioned chemically modified graphene oxide, and the chemically modified graphene oxides are cross-linked and combined by the graphene oxide ligand. In some embodiments of the present application, the display device is a QLED electroluminescent device, the quantum dot film is used as a quantum dot light-emitting layer of the QLED electroluminescent device, and the graphene oxide film is arranged on the surface of the quantum dot film to form a dense monomolecular protective layer, which can protect the quantum dots that need to be retained from being damaged or removed while eliminating the quantum dot residues using a strong developing agent, thereby avoiding the failure of the display device.

[0060] Optionally, in the QLED electroluminescent device described above, the quantum dot film comprises quantum dot bodies and quantum dot ligands combined on the quantum dot bodies, and the quantum dot ligands are cross-linked with the graphene oxide ligands. The cross-linking between the quantum dot ligands and the graphene oxide ligands makes the connection between the quantum dot film and the graphene oxide film more tight and firm. At the same time, the quantum dot ligands can be cross-linked with each other, so that stable connections are formed between the quantum dot bodies inside the quantum dot film.

[0061] Optionally, the quantum dot ligand has a structure of A'-B'-C', wherein A' is a second coordination group for binding with the quantum dot body, B' is a second linking group for connecting A' and C', and C' is a second cross-linking group for cross-linking, the second coordination group A', the second linking group B' and the second cross-linking group C' are sequentially connected by chemical bonds, the second cross-linking group is used for cross-linking reaction under light, the second cross-linking group can be cross-linked with the second cross-linking group, and the second cross-linking group can also be cross-linked with the first cross-linking group.

[0062] The groups of A', B' and C' are optionally connected by an alkyl chain or directly connected by chemical bonds.

[0063] Optionally, the second cross-linking group is an alkene group, an alkyne group, an ester group, an aldehyde group, a carbonyl group, an azide group, a cyano group, an oxirane group, an oxetane group, an oxetane group or an oxetane group.

[0064] In some embodiments of the present application, the quantum dot ligand can be 1-tridecylenic acid shown in formula (5), wherein the second coordination group A' is a carboxyl group for coordinating and connecting with the quantum dot body, the second linking group B' is a straight carbon chain of C 10 , and the second cross-linking group C' is a vinyl group. The structure of the quantum dot obtained after the quantum dot ligand shown in formula (5) is combined with the quantum dot body is shown in formula (6). Figure 4

[0065]

[0066] The preparation method of the quantum dot body combined with the quantum dot ligand to form a quantum dot structure is suitable for the prior art, and the present application does not make specific limitations. For example, when the quantum ligand is selected as 1-tridecylenic acid shown in formula (5), an optional exemplary preparation method comprises the following steps (a)-(e):

[0067] ​(a) Preparation of CdSe core: 0.4 mmol of CdO, 3.2 mmol of oleic acid OA, and 10 mL of 1-octadecene ODE were added into a 50 mL three-necked round bottom flask, heated at 120 °C, vacuumized for 1 h, and then purged with nitrogen. The solution was heated to 240 °C, and the solution in the flask became clear and transparent. 1 g of tri-n-octylphosphine TOP and 3 g of hexadecylamine were added, and the temperature was decreased to 150 °C. The solution was vacuumized for 30 min, and then purged with nitrogen. The temperature was increased to 280 °C. A clear solution of TOP-Se (2 mmol of Se, 2 mL of TOP, and 2.5 mL of ODE) was quickly injected into the flask. The solution was kept for 3 min, and then quickly cooled to room temperature. The quantum dots were extracted with a mixture of methanol and chloroform (3:1, by volume) for several times, and then dispersed in chloroform for use.

[0068] (b) Preparation of ZnS shell precursor: 0.3 mmol of Zn(Ac)2, 1 mmol of dodecanoic acid DDT, 6 mL of 1-octadecene ODE, and 4 mL of oleylamine OLA were added into a three-necked round bottom flask. After being heated at 90 °C and vacuumized-purged with nitrogen for three times, the solution was ready for use.

[0069] (c) Shell coating process: 2 mL of the CdSe chloroform solution, 2 mL of ODE, and 200 μL of OA were added into a three-necked round bottom flask. After being vacuumized-purged with nitrogen for three times at 120 °C, the temperature was increased to 240 °C. The ZnS shell precursor was transferred into the main reaction system at a rate of 1.5 mL / h.

[0070] (d) Washing process: In order to completely remove the free ligand, the washing process was divided into three steps. ① 100 mL of a mixture of acetone and methanol (7:3, by volume) was added into the three-necked round bottom flask containing the quantum dot solution. After being stirred at 60 °C for 10 min, the precipitate was obtained by centrifugation. ② The precipitate was completely dispersed in 20 mL of toluene, and then 100 mL of a mixture of acetone and methanol (3:7, by volume) was added. After being stirred at 60 °C for 10 min, the precipitate was obtained by centrifugation. ③ The precipitate was completely dispersed in 20 mL of toluene, and then added into a three-necked round bottom flask. 20 mL of glacial acetic acid and 70 mL of methanol were added. After being stirred at 70 °C for 10 min, the precipitate was obtained by centrifugation. The precipitate was dried in a vacuum drying oven at 60 °C, and then ground into powder for use.

[0071] (e) Ligand exchange of quantum dot material: 20 mg / ml of 5 mL of the quantum dot solution in n-octane was prepared in a three-necked round bottom flask. After being vacuumized-purged with nitrogen for three times at 80 °C, 5 mL of 60 mg / ml of the quantum dot ligand 1-tridecylenic acid (structure as shown in formula 5) in n-octane was injected. The reaction was carried out for 20 min, and then repeated step (d) for washing. The quantum dots modified with the quantum dot ligand were dissolved in n-octane for use, and the structure of the quantum dots modified with the quantum dot ligand was obtained.

[0072] After exposure, the second crosslinking group in the quantum dot ligand undergoes a crosslinking reaction to form a dense quantum dot film. Furthermore, the second crosslinking group in the quantum dot ligand can also undergo a crosslinking reaction with the active groups in the adjacent film layers to enhance the interlayer connection.

[0073] Optionally, in the above-mentioned QLED electroluminescent device, the QLED electroluminescent device further includes an electron transport layer disposed adjacent to the quantum dot light-emitting layer. The electron transport layer includes zinc oxide and zinc oxide ligands bound to the zinc oxide, and the quantum dot ligands can cross-link with the zinc oxide ligands. Through the cross-linking between the quantum dot ligands and the zinc oxide ligands, the connection between the quantum dot film and the electron transport layer becomes tighter and more robust. Simultaneously, the zinc oxide ligands can cross-link with each other, forming stable connections between the zinc oxide particles within the electron transport layer.

[0074] Optionally, the zinc oxide ligand has an A″-B″-C″ structure, wherein A″ is a third coordinating group bound to zinc oxide, B″ is a third linking group connecting A″ and C″, and C″ is a third crosslinking group for crosslinking. The third coordinating group A″, the third linking group B″, and the third crosslinking group C″ are sequentially linked by chemical bonds. The third crosslinking group is used to undergo a crosslinking reaction under light irradiation. The third crosslinking group can undergo a crosslinking reaction with itself and with the second crosslinking group.

[0075] The groups A″, B″, and C″ can be optionally linked by alkyl chains or directly by chemical bonds.

[0076] Optionally, the third coordinating group A″ is an amino group, a polyamino group, a hydroxy group, a polyhydroxy group, a mercapto group, a polymerase group, a thioether group, a polythioether group, a phosphin group, or an oxophosphin group.

[0077] Optionally, the third crosslinking group C″ is an olefinic group, an alkyneic group, an esteric group, an aldehyde group, a carbonyl group, an azide group, a cyano group, ethylene oxide, propylene oxide, butane oxide, or pentane oxide.

[0078] In some embodiments of this application, the zinc oxide ligand may be 1-tridecenoic acid as shown in formula (5), wherein the third coordinating group A″ is a carboxyl group for coordination with zinc oxide, and the third linking group B″ is a C 10 It has a linear carbon chain, and the third crosslinking group C″ is a vinyl group.

[0079] In some embodiments of this application, the zinc oxide ligand may be 13-mercapto-1-tetrideene as shown in formula (6), wherein the third coordinating group A″ is a mercapto group used for coordination linking with zinc oxide, and the third linking group B″ is a C 10a straight carbon chain, and the third cross-linking group C" is a vinyl group.

[0080]

[0081] In some embodiments of the present application, the specific form of zinc oxide can be zinc oxide nanoparticles or zinc oxide thin film prepared by sol-gel method. Whether it is zinc oxide nanoparticles or zinc oxide thin film prepared by sol-gel method, there are a large number of hydroxyl groups and Zn cations exposed on the outermost layer. The third coordination group A" including amino, polyamino, hydroxyl, polyhydroxyl, mercapto, polysulfhydryl, sulfide, polysulfide, phosphine, phosphine oxide, etc. can coordinate with the surface hydroxyl and Zn cations.

[0082] The process of obtaining the modified zinc oxide after the zinc oxide ligand is combined with the zinc oxide nanoparticles is shown in Figure 6 The process of obtaining the modified zinc oxide after the zinc oxide ligand is combined with the zinc oxide thin film prepared by sol-gel method is shown in Figure 7

[0083] The preparation method of zinc oxide combined with zinc oxide ligand to form a modified zinc oxide structure is suitable for the prior art, and the present application does not make specific limitations. For example, when the zinc oxide ligand is selected as 1-tridecene acid shown in formula (5) and 13-mercapto-1-tridecene shown in formula (6), an optional exemplary preparation method includes the following steps (a) and (b):

[0084] (a) When the form of zinc oxide is zinc oxide nanoparticles, prepare a zinc oxide nanoparticle film. For example, spin-coat zinc oxide nanoparticles, and then heat to form a film at 80-120°C. The electron transport layer material can also be selected from ion-doped zinc oxide nanoparticles, such as Mg, In, Al, Ga-doped zinc oxide nanoparticles, etc. The rotation speed of the film applicator is set to 500-2500 rpm to adjust the thickness of the film layer.

[0085] When the form of zinc oxide is zinc oxide thin film, the step of preparing the zinc oxide thin film can include dissolving 2g of zinc acetate (or zinc nitrate, etc.) in 10mL of a mixed solution of ethanolamine and n-butanol, placing the front film layer in the film applicator, dropping 90-120μL of the precursor solution onto the front film layer, spin-coating, and then placing it on a hot stage at 250-300 degrees to heat and volatilize the solvent.

[0086] (c) Soak the above-mentioned zinc oxide nanoparticle film or sol-gel prepared zinc oxide thin film in the zinc oxide ligand solution shown in formula (6) for reaction. The reaction process is shown in Figure 6 and Figure 7 ​The concentration of the zinc oxide ligand solution is 5-30 mg / ml, the soaking time is 5-10 mins, the soaking solvent is n-octane, then the ligand not connected to the zinc oxide is washed with n-octane, and then the solvent is removed by annealing at 120°C.

[0087] The zinc oxide film described above can be cross-linked between the zinc oxide ligands, and between the second cross-linking groups in the zinc oxide ligand and the quantum dot ligand in the subsequent quantum dot film preparation process, thereby enhancing the firmness of the layer and the interlayer connection.

[0088] In some embodiments of the present application, the display device comprises an electroluminescent device, the quantum dot film and the graphene oxide film arranged in sequence, the quantum dot film serving as a light conversion layer of the display device to convert the light emitted by the electroluminescent device into different colors. The graphene oxide film is arranged on the surface of the quantum dot film to form a dense monomolecular protective layer, which can protect the quantum dots that need to be retained from being damaged or removed while eliminating the quantum dot residues using a strong developing agent, thereby avoiding the failure of the display device.

[0089] Optionally, the electroluminescent device is an OLED electroluminescent device, and the quantum dot film is used to convert the light emitted by the OLED electroluminescent device into different colors. The OLED electroluminescent device can serve as a blue light source, i.e., a BOLED, in which case the quantum dot film comprises a red light conversion quantum dot film for converting blue light into red light and a green light conversion quantum dot film for converting blue light into green light. The OLED electroluminescent device can also serve as a white light source, i.e., a WOLED, in which case the quantum dot film comprises a red light conversion quantum dot film for converting white light into red light, a green light conversion quantum dot film for converting white light into green light, and a blue light conversion quantum dot film for converting white light into blue light.

[0090] Optionally, the electroluminescent device is a Micro LED electroluminescent device, and the quantum dot film is used to convert the light emitted by the Micro LED electroluminescent device into different colors. The Micro LED electroluminescent device can serve as a blue light source, in which case the quantum dot film comprises a red light conversion quantum dot film for converting blue light into red light and a green light conversion quantum dot film for converting blue light into green light. The Micro LED electroluminescent device can also serve as a white light source, in which case the quantum dot film comprises a red light conversion quantum dot film for converting white light into red light, a green light conversion quantum dot film for converting white light into green light, and a blue light conversion quantum dot film for converting white light into blue light.

[0091] In some embodiments of the present application, the graphene oxide film is provided with a plurality of graphene oxide ligands, and each of the graphene oxide film is provided in one-to-one correspondence with a sub-pixel of different color of the display device, and the cross-linking degree of the graphene oxide ligands in the same graphene oxide film is greater than the cross-linking degree of the graphene oxide ligands between adjacent graphene oxide films.

[0092] Optionally, when the display device is a QLED electroluminescent device, the quantum dot film as the quantum dot light-emitting layer can include a red quantum dot film, a green quantum dot film and a blue quantum dot film, and the graphene oxide film is prepared in correspondence with the red quantum dot film, the green quantum dot film and the blue quantum dot film, respectively. For example, in the preparation process of the display device, the red quantum dot film is prepared first, and in this process, the preparation of the first graphene oxide film corresponding to the red quantum dot film is completed, and in the exposure process of preparing the red quantum dot film, the graphene oxide ligands in the first graphene oxide film complete the cross-linking reaction; then the green quantum dot film is prepared, and in this process, the preparation of the second graphene oxide film corresponding to the green quantum dot film is completed, and in the exposure process of preparing the green quantum dot film, the graphene oxide ligands in the second graphene oxide film complete the cross-linking reaction, if the first graphene oxide film and the second graphene oxide film are connected in physical structure, since the first graphene oxide film has been exposed once, the first cross-linking groups on the graphene oxide ligands in the first graphene oxide film have all or most of them undergone cross-linking reaction, and in the exposure of the second graphene oxide film, the graphene oxide ligands in the second graphene oxide film cannot cross-link with the graphene oxide ligands in the first graphene oxide film or only a small amount of cross-linking reaction occurs, so that the cross-linking degree of the graphene oxide ligands between the first graphene oxide film and the second graphene oxide film is small, while the cross-linking degree of the graphene oxide ligands in the first graphene oxide film and the cross-linking degree of the graphene oxide ligands in the second graphene oxide film are both large; finally, the blue quantum dot film is prepared, and in this process, the preparation of the third graphene oxide film corresponding to the blue quantum dot film is completed, and in the exposure process of preparing the blue quantum dot film, the graphene oxide ligands in the third graphene oxide film complete the cross-linking reaction, if the second graphene oxide film and the third graphene oxide film are connected in physical structure, since the second graphene oxide film has been exposed once, the first cross-linking groups on the graphene oxide ligands in the second graphene oxide film have all or most of them undergone cross-linking reaction, and in the exposure of the third graphene oxide film, the graphene oxide ligands in the third graphene oxide film cannot cross-link with the graphene oxide ligands in the second graphene oxide film or only a small amount of cross-linking reaction occurs, so that the cross-linking degree of the graphene oxide ligands between the second graphene oxide film and the third graphene oxide film is small, while the cross-linking degree of the graphene oxide ligands in the second graphene oxide film and the cross-linking degree of the graphene oxide ligands in the third graphene oxide film are both large.

[0093] Optionally, when the display device is an OLED electroluminescent device, the quantum dot film as the light conversion layer can include a red light conversion quantum dot film, a green light conversion quantum dot film and a blue light conversion quantum dot film, and the graphene oxide film is prepared corresponding to the red light conversion quantum dot film, the green light conversion quantum dot film and the blue light conversion quantum dot film respectively. For example, in the preparation process of the display device, the red light conversion quantum dot film is prepared first, and in this process, the preparation of the first graphene oxide film corresponding to the red light conversion quantum dot film is completed, and in the exposure process of preparing the red light conversion quantum dot film, the graphene oxide ligand in the first graphene oxide film completes the cross-linking reaction; then the green light conversion quantum dot film is prepared, and in this process, the preparation of the second graphene oxide film corresponding to the green light conversion quantum dot film is completed, and in the exposure process of preparing the green light conversion quantum dot film, the graphene oxide ligand in the second graphene oxide film completes the cross-linking reaction, if the first graphene oxide film and the second graphene oxide film are connected in physical structure, since the first graphene oxide film has been exposed once, the first cross-linking group on the graphene oxide ligand in the first graphene oxide film has all or most of the cross-linking reaction, and in the exposure of the second graphene oxide film, the graphene oxide ligand in the second graphene oxide film cannot cross-link with the graphene oxide ligand in the first graphene oxide film or only a small amount of cross-linking reaction occurs, so that the cross-linking degree of the graphene oxide ligand between the first graphene oxide film and the second graphene oxide film is small, while the cross-linking degree of the graphene oxide ligand in the first graphene oxide film and the cross-linking degree of the graphene oxide ligand in the second graphene oxide film are large; finally, the blue light conversion quantum dot film is prepared, and in this process, the preparation of the third graphene oxide film corresponding to the blue light conversion quantum dot film is completed, and in the exposure process of preparing the blue light conversion quantum dot film, the graphene oxide ligand in the third graphene oxide film completes the cross-linking reaction, if the second graphene oxide film and the third graphene oxide film are connected in physical structure, since the second graphene oxide film has been exposed once, the first cross-linking group on the graphene oxide ligand in the second graphene oxide film has all or most of the cross-linking reaction, and in the exposure of the third graphene oxide film, the graphene oxide ligand in the third graphene oxide film cannot cross-link with the graphene oxide ligand in the second graphene oxide film or only a small amount of cross-linking reaction occurs, so that the cross-linking degree of the graphene oxide ligand between the second graphene oxide film and the third graphene oxide film is small, while the cross-linking degree of the graphene oxide ligand in the second graphene oxide film and the cross-linking degree of the graphene oxide ligand in the third graphene oxide film are large. In the third aspect of the present application, a preparation method of a display device is provided for preparing the aforementioned display device.In some embodiments of the present application, the display device can be a QLED electroluminescent device, which can be a normal structure or an inverted structure, and the QLED electroluminescent device comprises one or more of the following components: a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a quantum dot light-emitting layer, an electron blocking layer, a hole transport layer, a hole injection layer, and an anode, and at least has the quantum dot light-emitting layer and the graphene oxide film formed on the surface of the quantum dot light-emitting layer, and the selection of the components is determined according to actual needs. In some other embodiments of the present application, the display device comprises one or more of the following components: a substrate, a back plate, an electroluminescent device, the quantum dot film, and the graphene oxide film, and indicates that the quantum dot film and the graphene oxide film formed on the surface of the quantum dot film are provided, and the selection of the components is determined according to actual needs.

[0094] The preparation method of the display device at least comprises:

[0095] coating a quantum dot solution on the formed pre-film layer to form a quantum dot film;

[0096] spinning the chemically modified graphene oxide provided in the first aspect of the present application on the quantum dot film;

[0097] exposing the preset region of the quantum dot film according to the patterning requirement, so that the chemically modified graphene oxide in the exposed region is cross-linked to form a dense graphene oxide film;

[0098] developing, so that the chemically modified graphene oxide and the quantum dot film outside the exposed region are removed.

[0099] The following further describes a chemically modified graphene oxide, a display device, and a preparation method thereof provided in the present application.

[0100] Embodiment 1: Preparation method of chemically modified graphene oxide

[0101] Step 1, preparation of graphene oxide bulk.

[0102] The graphite powder, KMn04 and NaN03 are added in batches to the appropriate amount of concentrated sulfuric acid in a mass ratio of 2:6:1, while stirring, an ice water bath is carried out (control reaction temperature does not exceed 20℃), after a period of time, the liquid is heated to 35℃ and continue to stir for 30 minutes; then, add a certain amount of deionized water and continue to stir for 20 minutes, then add the appropriate amount of hydrogen peroxide, make the solution into bright yellow, and filter while hot, then wash with 5% hydrochloric acid solution and deionized water until no sulfate, finally remove the excess ions by dialysis and other methods, complete the preparation, then further exfoliation to obtain single-layer graphene oxide bulk, as described above method of solution ice water bath ultrasonic for one hour, then centrifuge at 2000-5000 rpm for 30 minutes, take the supernatant, that is, the well-dispersed graphene oxide bulk solution. The structure of the prepared graphene oxide bulk is shown in formula (1).

[0103] Step 2, the graphene oxide is modified with a photo-crosslinkable group. The photo-crosslinkable group in this step can be provided by the graphene oxide ligand structure shown in formula (2)-(4), respectively, and the specific preparation process is described in steps (a), (b) and (c) below.

[0104] (a) The graphene oxide ligand is selected as 3-butene-1-amine shown in formula (2). 10mg-50mg of graphene oxide ligand is added to 5ml of 10mg / ml graphene oxide bulk, and the reaction is carried out at 60℃ in water bath for 10-30min, so that the 3-butene-1-amine is modified to the graphene oxide bulk, and the chemically modified graphene oxide is obtained. The specific reaction is shown in formula (2). Figure 1 During the reaction, the carboxyl group on the graphene oxide bulk can react with 3-butene-1-amine, so that the graphene oxide bulk is modified with a crosslinkable double bond.

[0105] (b) The graphene oxide ligand is selected as but-3-yn-1-amine shown in formula (3). 10mg-50mg of graphene oxide ligand is added to 5ml of 10mg / ml graphene oxide bulk, and the reaction is carried out at 60℃ in water bath for 10-30min, so that the but-3-yn-1-amine is modified to the graphene oxide bulk, and the chemically modified graphene oxide is obtained. The specific reaction is shown in formula (3). Figure 2 During the reaction, the carboxyl group on the graphene oxide bulk can react with but-3-yn-1-amine, so that the graphene oxide bulk is modified with a crosslinkable triple bond.

[0106] (c) the allyl amine is selected as the graphene oxide ligand shown in formula (4). 10-50 mg of the graphene oxide ligand is added to 5 ml of 10 mg / ml graphene oxide bulk, and the reaction is carried out at 60°C in a water bath for 10-30 min, so that the allyl amine is modified to the graphene oxide bulk to obtain chemically modified graphene oxide. The specific reaction is shown in Figure 3 During the reaction, the carboxyl groups on the graphene oxide bulk can react with the allyl amine, so that the graphene oxide bulk is modified with a cross-linkable double bond.

[0107] Example 2: A preparation method of a QLED electroluminescent device

[0108] Step 1, cleaning. The conductive glass (ITO or FTO, etc.) is cleaned with water, isopropanol, and ultrasonic cleaning, and is treated with ultraviolet (UV) for 5-10 min.

[0109] Step 2, introducing an electron transport layer. The electron transport layer can be a zinc oxide nanoparticle film or a zinc oxide film, and the following step (a) or step (b) is selected according to the specific production requirements.

[0110] (a) preparing a zinc oxide nanoparticle film. For example, spin-coating zinc oxide nanoparticles, and then heating at 80-120°C to form a film. The electron transport layer material can also be selected from ion-doped zinc oxide nanoparticles, such as Mg, In, Al, Ga-doped zinc oxide nanoparticles, etc. The rotation speed of the film applicator is set to 500-2500 rpm to adjust the thickness of the film layer.

[0111] (b) preparing a zinc oxide film. 1 g of zinc acetate (or zinc nitrate, etc.) is dissolved in 5 mL of a mixed solution of ethanolamine and n-butanol. The conductive glass is placed in the film applicator, and 90-120 μL of the zinc precursor solution is added to the conductive glass and spin-coated. The conductive glass is placed on a hot stage at 250-300 degrees, heated and solvent is released, and a polyetherimide film layer is introduced on the conductive glass.

[0112] Step 3, introducing a red quantum dot film (RQD). 60-120 μL of a red quantum dot solution is added to the conductive glass and spin-coated to form a quantum dot film, as shown in A of Figure 8 .

[0113] Step 4, introducing a photo-crosslinkable graphene oxide layer.

[0114] (a) chemically modified graphene oxide is prepared by the method of Example 1.

[0115] (b) the chemically modified graphene oxide is spin-coated on the quantum dot film obtained in step 3, and the red pixel area is exposed, and the exposure method is as shown in Figure 8The exposed area is shown in FIG. 1A. The chemically modified graphene oxide in the exposed area is cross-linked to form a dense graphene oxide film. Subsequently, the film is developed so that the chemically modified graphene oxide and quantum dot film outside the exposed area are removed, and a structure as shown in FIG. 1B is obtained. Figure 8 During the developing process, a dense graphene oxide film is formed on the quantum dot film in the red pixel area, which can protect the quantum dots in this area from being over-developed during the developing process.

[0116] Step 5: Introducing a hole transport layer.

[0117] A hole transport layer is formed on the above film layer structure by spin coating or evaporation, etc. The organic material for the hole transport layer can be TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)) or PVK (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)), or other commercial hole transport compounds, etc. The film forming conditions for TFB are: film forming in inert gas at 130-150°C. The film thickness can be controlled according to the rotation speed of the film applicator. In this step, the hole transport material can also be evaporated.

[0118] Step 6: Introducing a hole injection layer. A hole injection layer is formed on the above conductive glass by spin coating or evaporation, etc. The organic material for the hole injection layer can be PEDOT:PSS 4083 (poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate) or other commercial compounds suitable for hole injection layer, etc. The film forming temperature for PEDOT is 130-150°C in air, etc. The film thickness can be controlled according to the rotation speed of the film applicator. In this step, the hole injection material can also be evaporated.

[0119] Step 7: Introducing an electrode. Finally, an electrode material is introduced, such as evaporated aluminum film, silver film or sputtered indium zinc oxide (IZO) film to prepare a QLED device.

[0120] Step 8: Packaging. A packaging cover plate is added, and the device is packaged using ultraviolet curing glue to obtain a QLED electroluminescent device.

[0121] The QLED electroluminescent device prepared by the above steps 1-8 has red color. By repeating steps 3 and 4, patterned green and blue pixel points are formed, and a full-color QLED electroluminescent device is formed. Specifically, between steps 4 and 5, the following steps 3', 4', 3" and 4" are sequentially included.

[0122] Step 3': Introducing a green quantum dot film (GQD). 60-120 μL of green quantum dot solution is dropped onto the conductive glass, and spin coating is performed to form a quantum dot film, as shown in FIG. 1C. Figure 8

[0123] ​Step 4', introducing a photo-crosslinkable graphene oxide layer.

[0124] (a) Chemically modified graphene oxide is prepared by the method of Example 1.

[0125] (b) The chemically modified graphene oxide is spin-coated on the quantum dot film obtained in Step 3', obtaining a structure as shown in FIG. D, and the green pixel area is exposed, the exposure mode referring to that shown in FIG. E, so that in the exposed area, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film, and then developed, so that outside the exposed area, the chemically modified graphene oxide and the quantum dot film are removed, obtaining a structure as shown in FIG. F. During the development, the quantum dot film in the green pixel area is formed with a dense graphene oxide film, which can protect the quantum dots in this area from being over-developed during the development. Figure 8 Figure 8 (b) The chemically modified graphene oxide is spin-coated on the quantum dot film obtained in Step 3', obtaining a structure as shown in FIG. D, and the green pixel area is exposed, the exposure mode referring to that shown in FIG. E, so that in the exposed area, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film, and then developed, so that outside the exposed area, the chemically modified graphene oxide and the quantum dot film are removed, obtaining a structure as shown in FIG. F. During the development, the quantum dot film in the green pixel area is formed with a dense graphene oxide film, which can protect the quantum dots in this area from being over-developed during the development. Figure 8

[0126] Step 3", introducing a blue quantum dot film (BQD). 60-120 μL of blue quantum dot solution is dropped onto the conductive glass and spin-coated into a film to form a quantum dot film, as shown in FIG. G. Figure 8

[0127] Step 4", introducing a photo-crosslinkable graphene oxide layer.

[0128] (a) Chemically modified graphene oxide is prepared by the method of Example 1.

[0129] (b) The chemically modified graphene oxide is spin-coated on the quantum dot film obtained in Step 3", obtaining a structure as shown in FIG. H, and the blue pixel area is exposed, the exposure mode referring to that shown in FIG. I, so that in the exposed area, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film, and then developed, so that outside the exposed area, the chemically modified graphene oxide and the quantum dot film are removed, obtaining a structure as shown in FIG. J. During the development, the quantum dot film in the blue pixel area is formed with a dense graphene oxide film, which can protect the quantum dots in this area from being over-developed during the development. Figure 8 Figure 8

[0130] It should be noted that in this embodiment, the patterning order of the red quantum dots, the green quantum dots and the blue quantum dots can also be adjusted as needed.

[0131] Example 3: A method for preparing a QLED electroluminescent device

[0132] Step 1, cleaning. The conductive glass (ITO or FTO, etc.) is cleaned with water, isopropanol, ultrasonic cleaning, and ultraviolet UV treatment for 5-10 min. ​​​​​

[0133] Step 2, introducing an electron transport layer. The electron transport layer can be a zinc oxide nanoparticle film or a zinc oxide film, and the following step (a) or step (b) is selected according to the specific production requirements.

[0134] (a) preparing a zinc oxide nanoparticle film. For example, spin-coating zinc oxide nanoparticles, and then heating to form a film at 80-120°C. The electron transport layer material can also be selected from ion-doped zinc oxide nanoparticles, such as Mg, In, Al, Ga-doped zinc oxide nanoparticles, etc. The rotation speed of the film applicator is set to 500-2500 rpm to adjust the thickness of the film layer.

[0135] (b) preparing a zinc oxide film. Dissolve 1 g of zinc acetate (or zinc nitrate, etc.) in 5 mL of a mixed solution of ethanolamine and n-butanol. Place the above conductive glass in the film applicator, and drop 90-120 μL of the zinc precursor solution onto the conductive glass and spin-coat. Place the above conductive glass on a hot stage at 250-300 degrees, heat and release the solvent, and introduce a polyetherimide film layer on the above conductive glass.

[0136] Step 3, introducing a red quantum dot film layer. Drop 60-120 μL of a red quantum dot solution onto the conductive glass and spin-coat a red quantum dot film, the red quantum dot solution including a red quantum dot body and a modified red quantum dot structure formed by combining a quantum dot ligand with the red quantum dot body, the quantum dot ligand being 1-tridecyne acid, and the quantum dot structure obtained after the quantum dot ligand is combined with the red quantum dot body being as shown in Figure 4 .

[0137] Step 4, introducing a photo-crosslinkable graphene oxide layer.

[0138] (a) using the method of Example 1 to prepare chemically modified graphene oxide.

[0139] (b) spin-coating the chemically modified graphene oxide on the red quantum dot film obtained in Step 3, and exposing the red pixel area to light, so that in the exposed area, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film, the red quantum dot structure modified by the quantum dot ligand is crosslinked to form a stable quantum dot film, and crosslinking also occurs between the chemically modified graphene oxide and the red quantum dot structure modified by the quantum dot ligand, the reaction process being as shown in Figure 5 . Subsequently, develop so that outside the exposed area, the chemically modified graphene oxide and the red quantum dot film are removed. During the development process, a dense graphene oxide film is formed on the quantum dot film in the red pixel area, which can protect the quantum dots in this area from being over-developed during the development process, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0140] Step 5, introducing a hole transport layer.

[0141] A hole transport layer is formed on the above-mentioned film layer structure by spin coating or evaporation, etc. The organic material for the hole injection layer can be TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)) or PVK (poly(ethylene carboxazol)) or other commercial hole transport compounds, etc. The film forming conditions of TFB are: 130-150°C film forming in inert gas. The film thickness can be controlled according to the rotation speed of the film applicator. The hole transport material can also be evaporated in this step.

[0142] Step 6: Introducing a hole injection layer. A hole injection layer is formed on the above-mentioned conductive glass by spin coating or evaporation, etc. The organic material for the hole injection layer can be PEDOT:PSS 4083 (poly 3,4-ethylenedioxythiophene / polystyrene sulfonate) or other commercial compounds suitable for hole injection layer, etc. The film forming temperature of PEDOT is 130-150°C in air, etc. The film thickness can be controlled according to the rotation speed of the film applicator. The hole injection material can also be evaporated in this step.

[0143] Step 7: Introducing an electrode. Finally, an electrode material is introduced, such as evaporated aluminum film, silver film or sputtered indium zinc oxide (IZO) film to prepare a QLED device.

[0144] Step 8: Encapsulation. A cover plate is added to encapsulate the device using ultraviolet curing glue to prepare a QLED electroluminescent device.

[0145] The QLED electroluminescent device prepared by the above steps 1-8 has red color. By repeating steps 3 and 4, patterned green and blue pixel points are formed to further form a full-color QLED electroluminescent device. Specifically, between steps 4 and 5, the following steps 3', 4', 3" and 4" are further included.

[0146] Step 3': Introducing a green quantum dot film layer. 60-120 μL of green quantum dot solution is dropped onto the conductive glass, and a green quantum dot film is formed by spin coating. The green quantum dot solution includes green quantum dot bulk and modified green quantum dot structure formed by combining quantum dot ligand. The quantum dot ligand is 1-tridecanoic acid. The quantum dot structure obtained after the combination of the quantum dot ligand and the green quantum dot bulk is shown in Figure 4 .

[0147] Step 4': Introducing a photo-crosslinkable graphene oxide layer.

[0148] (a) The chemically modified graphene oxide is prepared by the method of Example 1.

[0149] (b) The chemically modified graphene oxide is spin-coated on the green quantum dot film obtained in step 3', and the green pixel region is exposed, so that in the exposed region, the chemically modified graphene oxide is cross-linked to form a dense graphene oxide film, the green quantum dot structure modified by the quantum dot ligand is cross-linked to form a stable quantum dot film, and cross-linking also occurs between the chemically modified graphene oxide and the green quantum dot structure modified by the quantum dot ligand. Subsequently, development is performed, so that outside the exposed region, the chemically modified graphene oxide and the green quantum dot film are removed. During the development process, a dense graphene oxide film is formed on the quantum dot film of the green pixel region, which can protect the quantum dots in this region from being over-developed during the development process, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0150] Step 3", introducing a blue quantum dot film layer. 60-120 μL of a blue quantum dot solution is dropped onto the conductive glass, and a blue quantum dot film is spin-coated, the blue quantum dot solution including a blue quantum dot body and a modified blue quantum dot structure formed by the combination of the blue quantum dot body and a quantum dot ligand, the quantum dot ligand being 1-tridecyne acid, and the quantum dot structure obtained after the combination of the quantum dot ligand and the blue quantum dot body being as shown in Figure 4 .

[0151] Step 4", introducing a photo-cross-linkable graphene oxide layer.

[0152] (a) The chemically modified graphene oxide is prepared by the method of Example 1.

[0153] (b) The chemically modified graphene oxide is spin-coated on the blue quantum dot film obtained in step 3", and the blue pixel region is exposed, so that in the exposed region, the chemically modified graphene oxide is cross-linked to form a dense graphene oxide film, the blue quantum dot structure modified by the quantum dot ligand is cross-linked to form a stable quantum dot film, and cross-linking also occurs between the chemically modified graphene oxide and the blue quantum dot structure modified by the quantum dot ligand. Subsequently, development is performed, so that outside the exposed region, the chemically modified graphene oxide and the blue quantum dot film are removed. During the development process, a dense graphene oxide film is formed on the quantum dot film of the blue pixel region, which can protect the quantum dots in this region from being over-developed during the development process, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0154] It should be noted that in this embodiment, the patterning order of the red quantum dots, the green quantum dots, and the blue quantum dots can also be adjusted as needed. The patterning order of the red quantum dots, the green quantum dots, and the blue quantum dots can be referred to as shown in Figure 8 , and will not be described here again.

[0155] Embodiment 4: a preparation method of a QLED electroluminescent device

[0156] Step 1, cleaning. The conductive glass (ITO or FTO, etc.) is cleaned with water, isopropanol, and ultrasonic cleaning, respectively, and is treated with ultraviolet UV for 5-10 min.

[0157] Step 2, introducing an electron transport layer. The electron transport layer can be a zinc oxide nanoparticle film or a zinc oxide film. According to the specific production requirements, the following steps (a) or (b) are selected, and then step (c) is performed.

[0158] (a) Preparation of a zinc oxide nanoparticle film. For example, spin-coat zinc oxide nanoparticles, and then heat to form a film at 80-120°C. The electron transport layer material can also be ion-doped zinc oxide nanoparticles, such as Mg, In, Al, Ga-doped zinc oxide nanoparticles, etc. The rotation speed of the film applicator is set to 500-2500 rpm to adjust the thickness of the film layer.

[0159] (b) Preparation of a zinc oxide film. Dissolve 1 g of zinc acetate (or zinc nitrate, etc.) in 5 mL of a mixed solution of ethanolamine and n-butanol. Place the above conductive glass in the film applicator, and drop 90-120 μL of the zinc precursor solution onto the conductive glass and spin-coat. Place the above conductive glass on a hot stage at 250-300 degrees, heat and release the solvent, and introduce a polyetherimide film layer on the above conductive glass.

[0160] (c) The zinc oxide nanoparticle film obtained in step (a) or the zinc oxide film prepared by sol-gel in step (b) is soaked in the zinc oxide ligand solution represented by formula (5) and formula (6) for reaction. The reaction process is described with reference to Figure 6 and Figure 7 . The concentration of the zinc oxide ligand solution is 5 mg / ml-30 mg / ml, the amount-of-substance ratio of the zinc oxide ligands represented by formula (5) and formula (6) is 1:1, the soaking time is 5-10 min, the soaking solvent is n-octane, then take out and wash the unreacted ligand with n-octane, and then anneal at 120°C to remove the solvent.

[0161] Step 3, introducing a red quantum dot film layer. Drop 60-120 μL of a red quantum dot solution onto the conductive glass and spin-coat a red quantum dot film. The red quantum dot solution includes a modified red quantum dot structure formed by combining a red quantum dot body and a quantum dot ligand, and the quantum dot ligand is 1-tridecylenic acid. The quantum dot structure obtained after the quantum dot ligand is combined with the red quantum dot body is shown in Figure 4 .

[0162] Step 4, introducing a photo-crosslinkable graphene oxide layer.

[0163] (a) Chemically modified graphene oxide is prepared by the method of Example 1.

[0164] (b) The chemically modified graphene oxide is spin-coated on the red quantum dot film obtained in step 3, and the red pixel area is exposed, so that in the exposed area, the chemically modified graphene oxide is cross-linked to form a dense graphene oxide film, the red quantum dot structure modified by the quantum dot ligand is cross-linked to form a stable quantum dot film, the zinc oxide film modified by the zinc oxide ligand is cross-linked to form a dense electron transport layer, and cross-linking also occurs between the chemically modified graphene oxide and the red quantum dot structure modified by the quantum dot ligand, and between the red quantum dot structure modified by the quantum dot ligand and the zinc oxide film modified by the zinc oxide ligand. Subsequently, development is performed, so that outside the exposed area, the chemically modified graphene oxide and the red quantum dot film are removed. During development, the dense graphene oxide film formed on the quantum dot film of the red pixel area can protect the quantum dots in this area from being over-developed during development, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0165] Step 5, introducing a hole transport layer.

[0166] A hole transport layer is formed on the above film layer structure by spin coating or evaporation, etc. The organic material used as the hole injection layer can be TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)), or PVK (polyvinylcarbazole), or other commercial hole transport compounds, etc. Among them, the film formation conditions of TFB are: film formation in inert gas at 130-150°C. The film thickness can be controlled according to the rotation speed of the coating machine. In this step, the hole transport material can also be evaporated.

[0167] Step 6, introducing a hole injection layer. A hole injection layer is formed on the above conductive glass by spin coating or evaporation, etc. The organic material used as the hole injection layer can be PEDOT:PSS 4083 (poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate) or other commercial compounds suitable for hole injection layer, etc. Among them, the film formation temperature of PEDOT is 130-150°C in air, etc. The film thickness can be controlled according to the rotation speed of the coating machine. In this step, the hole injection material can also be evaporated.

[0168] Step 7, introducing an electrode. Finally, an electrode material is introduced, such as evaporated aluminum film, silver film or sputtered indium zinc oxide (IZO) film to prepare a QLED device.

[0169] Step 8, packaging. A packaging cover plate is added, and the device is packaged using ultraviolet curing glue to obtain a QLED electroluminescent device.

[0170] The QLED electroluminescent device prepared by the above steps 1-step 8 is red in color. By repeating steps 3 and 4, patterned green and blue pixel points are formed, and a full-color QLED electroluminescent device is formed. Specifically, between steps 4 and 5, the following steps 3', 4', 3" and 4" are also included in sequence.

[0171] Step 3', introducing a green quantum dot film layer. 60-120 μL of green quantum dot solution is dropped onto the conductive glass, and a green quantum dot film is spin-coated. The green quantum dot solution includes green quantum dot bodies and modified green quantum dot structures formed by the combination of quantum dot ligands. The quantum dot ligand is 1-tridecyne acid. The quantum dot structure obtained after the combination of the quantum dot ligand and the green quantum dot body is shown in the figure.

[0172] Step 4', introducing a photo-crosslinkable graphene oxide layer.

[0173] (a) Chemically modified graphene oxide is prepared by the method of Example 1.

[0174] (b) The chemically modified graphene oxide is spin-coated on the green quantum dot film obtained in step 3, and the green pixel area is exposed to light, so that in the exposed area, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film, the green quantum dot structure modified by the quantum dot ligand is crosslinked to form a stable quantum dot film, the zinc oxide film modified by the zinc oxide ligand is crosslinked to form a dense electron transport layer, and crosslinking also occurs between the chemically modified graphene oxide and the green quantum dot structure modified by the quantum dot ligand, as well as between the green quantum dot structure modified by the quantum dot ligand and the zinc oxide film modified by the zinc oxide ligand. Subsequently, development is performed so that outside the exposed area, the chemically modified graphene oxide and the green quantum dot film are removed. During development, a dense graphene oxide film is formed on the quantum dot film of the green pixel area, which can protect the quantum dots in this area from being overdeveloped during development, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0175] Step 3", introducing a blue quantum dot film layer. 60-120 μL of blue quantum dot solution is dropped onto the conductive glass, and a blue quantum dot film is spin-coated. The blue quantum dot solution includes blue quantum dot bodies and modified blue quantum dot structures formed by the combination of quantum dot ligands. The quantum dot ligand is 1-tridecyne acid. The quantum dot structure obtained after the combination of the quantum dot ligand and the blue quantum dot body is shown in the figure.

[0176] Step 4", introducing a photo-crosslinkable graphene oxide layer.

[0177] (a) Chemically modified graphene oxide is prepared by the method of Example 1.

[0178] (b) spin-coating the chemically modified graphene oxide on the blue quantum dot film obtained in step 3, and exposing the blue pixel area, so that in the exposed area, the chemically modified graphene oxide is cross-linked to form a dense graphene oxide film, the blue quantum dot structure modified by quantum dot ligands is cross-linked to form a stable quantum dot film, the zinc oxide film modified by zinc oxide ligands is cross-linked to form a dense electron transport layer, and cross-linking also occurs between the chemically modified graphene oxide and the blue quantum dot structure modified by quantum dot ligands, and cross-linking also occurs between the blue quantum dot structure modified by quantum dot ligands and the zinc oxide film modified by zinc oxide ligands. Subsequently, development is performed, so that outside the exposed area, the chemically modified graphene oxide and the blue quantum dot film are removed. During development, a dense graphene oxide film is formed on the quantum dot film of the blue pixel area, which can protect the quantum dots in this area from being over-developed during development, and stable connections are formed inside the quantum dot film and between the quantum dot film and the graphene oxide film.

[0179] It should be noted that in this embodiment, the patterning order of the red quantum dots, the green quantum dots and the blue quantum dots can also be adjusted as needed. The patterning order of the red quantum dots, the green quantum dots and the blue quantum dots can refer to the above description, and will not be described here again. Figure 8

[0180] Embodiment 5: A preparation method of a BOLED-QD full-color display device

[0181] Step 1: A driving circuit layer is prepared on a substrate.

[0182] In this step, the substrate can be a hard substrate or a flexible substrate. The material of the hard substrate includes but is not limited to glass, and the material of the flexible substrate includes but is not limited to polyimide (PI). The driving circuit layer in this embodiment is provided with a pixel driving circuit, which can include a plurality of transistor structures. The entire surface of the substrate can be first deposited with a buffer layer and then formed with the driving circuit layer, or the buffer layer can not be included or a plurality of buffer layers can be included according to the situation.

[0183] Step 2: A light-emitting layer is prepared on the driving circuit layer.

[0184] The light-emitting device in the light-emitting layer is a blue light-emitting OLED electroluminescent device, i.e., a BOLED. The specific arrangement mode of the light-emitting device in the light-emitting layer can be flexibly selected by a person skilled in the art according to the actual situation.

[0185] Step 3: A light conversion layer and a photo-crosslinkable graphene oxide layer are prepared above the light-emitting layer.

[0186] ​On the basis of the formed light-emitting layer, a light-blocking layer film is coated, and a light-blocking block pattern is formed by a photoetching process. Specifically, the light-blocking block is preferably a black matrix (BM). After the light-blocking block is completed, a quantum dot film is produced. The quantum dot film includes a red light conversion quantum dot film for converting blue light into red light and a green light conversion quantum dot film for converting blue light into green light.

[0187] (a) First, a red light conversion quantum dot film (RQD) is introduced. A red light conversion quantum dot solution is dropped onto the surface of the light-emitting layer, and spin coating is performed to form a red light conversion quantum dot film. For reference, see Figure 9 A in the specification. The red light conversion quantum dot solution includes red light conversion quantum dots and modified red light conversion quantum dot structures formed by combining quantum dot ligands with the red light conversion quantum dots. The quantum dot ligands are 1-tridecyne acid.

[0188] (b) The method of Example 1 is used to produce chemically modified graphene oxide. The only difference from Example 1 is that the graphene oxide ligand is 3-butene-1-amine shown in formula (2). The chemically modified graphene oxide is spin coated on the red light conversion quantum dot film obtained in step (a) to achieve the structure shown in Figure 9 A in the specification, and the red pixel area is exposed. For reference, see the exposure method shown in Figure 9 A in the specification. In the exposure process, the dense graphene oxide film formed on the quantum dot film of the red pixel area can protect the quantum dots in this area from being overdeveloped during the developing process. Figure 9

[0189] (c) Then, a green light conversion quantum dot film (GQD) is introduced. A green light conversion quantum dot solution is dropped onto the surface of the light-emitting layer, and spin coating is performed to form a green light conversion quantum dot film. For reference, see the structure shown in Figure 9 C in the specification. The green light conversion quantum dot solution includes green light conversion quantum dots and modified green light conversion quantum dot structures formed by combining quantum dot ligands with the green light conversion quantum dots. The quantum dot ligands are 1-tridecyne acid.

[0190] (d) The method of Example 1 is used to produce chemically modified graphene oxide. The only difference from Example 1 is that the graphene oxide ligand is 3-butene-1-amine shown in formula (2). The chemically modified graphene oxide is spin coated on the green light conversion quantum dot film obtained in step (a) to achieve the structure shown in Figure 9 D in the specification, and the green pixel area is exposed. For reference, see the exposure method shown in Figure 9 ​The chemically modified graphene oxide in the exposed area is cross-linked to form a dense graphene oxide film. Subsequently, development is performed so that the chemically modified graphene oxide and the green light conversion quantum dot film outside the exposed area are removed, and a structure as shown in Figure 9 In the development process, a dense graphene oxide film is formed on the quantum dot film of the green pixel area, which can protect the quantum dots in this area from being over-developed in the development process.

[0191] It should be noted that in this step, the patterning order of the red light conversion quantum dots and the green light conversion quantum dots can also be adjusted as needed.

[0192] Step 4: Coating the film, curing and shaping to form a flat layer to obtain the BOLED-QD full-color display device.

[0193] Example 6: A method for preparing a WOLED-QD full-color display device

[0194] Step 1: Fabricating a driving circuit layer on a substrate.

[0195] In this step, the substrate can be a hard substrate or a flexible substrate. The material of the hard substrate includes but is not limited to glass, and the material of the flexible substrate 1 includes but is not limited to polyimide (PI). The driving circuit layer in this embodiment is provided with a pixel driving circuit, which can include several transistor structures. The entire surface of the substrate can be first deposited with a buffer layer and then formed with a driving circuit layer, or it can not include a buffer layer or include multiple buffer layers according to the situation.

[0196] Step 2: Fabricating a light-emitting layer on the driving circuit layer.

[0197] The light-emitting device in the light-emitting layer is a white light-emitting OLED electroluminescent device, i.e., WOLED. The specific arrangement of the light-emitting device in the light-emitting layer can be flexibly selected by those skilled in the art according to the actual situation.

[0198] Step 3: Fabricating a light conversion layer and a photo-crosslinkable graphene oxide layer above the light-emitting layer.

[0199] On the basis of the formed light-emitting layer, a light-blocking layer film is coated, and a light-blocking block pattern is formed by a photolithography process. Specifically, the light-blocking block is preferably a black matrix (BM). After the light-blocking block is fabricated, a quantum dot film is fabricated. The quantum dot film includes a red light conversion quantum dot film for converting blue light into red light and a green light conversion quantum dot film for converting blue light into green light.

[0200] (a) First, introduce the red light conversion quantum dot film (RQD), drop the red light conversion quantum dot solution onto the surface of the light-emitting layer, and spin coat it into a red light conversion quantum dot film, as shown in Figure 10The red light conversion quantum dot solution includes red light conversion quantum dot bodies and modified red light conversion quantum dot structures formed by quantum dot ligands. The quantum dot ligands are 1-tridecyne acid.

[0201] (b) The chemically modified graphene oxide is prepared by the method of Example 1. The chemically modified graphene oxide is spin-coated on the red light conversion quantum dot film obtained in step (a) to obtain a structure as shown in Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to

[0202] (c) Then introduce the green light conversion quantum dot film (GQD), drop the green light conversion quantum dot solution on the surface of the light-emitting layer, spin-coat into a green light conversion quantum dot film to obtain a structure as shown in Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to

[0203] (d) The chemically modified graphene oxide is prepared by the method of Example 1. The chemically modified graphene oxide is spin-coated on the green light conversion quantum dot film obtained in step (a) to obtain a structure as shown in Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to

[0204] (c) Then introduce the blue light conversion quantum dot film (BQD), drop the blue light conversion quantum dot solution on the surface of the light-emitting layer, spin-coat into a blue light conversion quantum dot film to obtain a structure as shown in Figure 10 The structure of the middle A, and the red pixel area is exposed, the exposure method is referred to

[0205] (d) The chemically modified graphene oxide is prepared by the method of Example 1. The chemically modified graphene oxide is spin-coated on the blue light conversion quantum dot film obtained in step (a) to obtain a structure as shown in FIG. 2B, and the blue pixel region is exposed, the exposure mode referring to FIG. 2C, so that the chemically modified graphene oxide in the exposed region is cross-linked to form a dense graphene oxide film. Subsequently, development is performed so that the chemically modified graphene oxide and the blue light conversion quantum dot film outside the exposed region are removed to obtain a structure as shown in FIG. 2D. Figure 10 Figure 10 Figure 10

[0206] It should be noted that in this step, the patterning order of the red light conversion quantum dots, the green light conversion quantum dots and the blue light conversion quantum dots can also be adjusted as needed.

[0207] Step 4, coating the film, curing and shaping to form a flat layer to obtain a WOLED-QD full-color display device.

[0208] Example 7: A method for preparing a Micro LED-QD full-color display device

[0209] Step 1, making a driving circuit layer on a substrate.

[0210] In this step, the substrate can be a hard substrate or a flexible substrate. The material of the hard substrate includes but is not limited to glass, and the material of the flexible substrate 1 includes but is not limited to polyimide (PI). The driving circuit layer in this embodiment is provided with a pixel driving circuit, which can include a plurality of transistor structures. The entire surface of the substrate can be first deposited with a buffer layer and then formed with a driving circuit layer, or it can not include a buffer layer or include multiple buffer layers according to the situation.

[0211] Step 2, making a light-emitting layer on the driving circuit layer.

[0212] The light-emitting device in the light-emitting layer is a plurality of arrayed micro light-emitting diodes, i.e. Micro LED. The Micro LED emits blue light. The specific arrangement mode of the light-emitting device in the light-emitting layer can be flexibly selected by those skilled in the art according to the actual situation.

[0213] Step 3, making a light conversion layer and a photo-crosslinkable graphene oxide layer above the light-emitting device of the light-emitting layer.

[0214] (a) First, introduce a red light conversion quantum dot film (RQD), drop a red light conversion quantum dot solution onto the surface of the light-emitting layer, and spin-coat it into a red light conversion quantum dot film, referring to FIG. 3A.​​​Figure 11 The red light conversion quantum dot solution includes red light conversion quantum dot bodies and modified red light conversion quantum dot structures formed by quantum dot ligands. The quantum dot ligands are 1-tridecyne acid.

[0215] (b) The chemically modified graphene oxide is prepared by the method of Example 1, except that the graphene oxide ligand is but-3-yn-1-amine shown in formula (3). The chemically modified graphene oxide is spin-coated on the red light conversion quantum dot film obtained in step (a) to obtain a structure as shown in Figure 11 The red light conversion quantum dot solution includes red light conversion quantum dot bodies and modified red light conversion quantum dot structures formed by quantum dot ligands. The quantum dot ligands are 1-tridecyne acid. Figure 11 The chemically modified graphene oxide is cross-linked to form a dense graphene oxide film in the exposed area. Subsequently, development is performed so that the chemically modified graphene oxide and the red light conversion quantum dot film are removed outside the exposed area to obtain a structure as shown in Figure 11 The chemically modified graphene oxide is cross-linked to form a dense graphene oxide film in the exposed area. Subsequently, development is performed so that the chemically modified graphene oxide and the red light conversion quantum dot film are removed outside the exposed area to obtain a structure as shown in

[0216] (c) Then, a green light conversion quantum dot film (GQD) is introduced. A green light conversion quantum dot solution is dropped onto the surface of the light-emitting layer and spin-coated to form a green light conversion quantum dot film. Refer to Figure 11 The green light conversion quantum dot solution includes green light conversion quantum dot bodies and modified green light conversion quantum dot structures formed by quantum dot ligands. The quantum dot ligands are 1-tridecyne acid.

[0217] (d) The chemically modified graphene oxide is prepared by the method of Example 1, except that the graphene oxide ligand is but-3-yn-1-amine shown in formula (3). The chemically modified graphene oxide is spin-coated on the green light conversion quantum dot film obtained in step (c) to obtain a structure as shown in Figure 11 The green light conversion quantum dot solution includes green light conversion quantum dot bodies and modified green light conversion quantum dot structures formed by quantum dot ligands. The quantum dot ligands are 1-tridecyne acid. Figure 11 The chemically modified graphene oxide is cross-linked to form a dense graphene oxide film in the exposed area. Subsequently, development is performed so that the chemically modified graphene oxide and the green light conversion quantum dot film are removed outside the exposed area to obtain a structure as shown in Figure 11 The chemically modified graphene oxide is cross-linked to form a dense graphene oxide film in the exposed area. Subsequently, development is performed so that the chemically modified graphene oxide and the green light conversion quantum dot film are removed outside the exposed area to obtain a structure as shown in

[0218] It should be noted that in this step, the patterning order of the red light conversion quantum dots and the green light conversion quantum dots can also be adjusted as needed.

[0219] Step 4, coating thin film, curing and shaping, forming a flat layer, and obtaining a Micro LED-QD full-color display device.

[0220] The foregoing is just a specific implementation of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A display device, characterized by comprising: The quantum dot film and the graphene oxide film formed on the surface of the quantum dot film, the graphene oxide film comprising chemically modified graphene oxide, the chemically modified graphene oxide being cross-linked and combined through the graphene oxide ligand; The chemically modified graphene oxide comprises graphene oxide bodies and graphene oxide ligands combined on the graphene oxide bodies, the graphene oxide bodies being formed with oxygen-containing groups, the graphene oxide ligands being combined on the oxygen-containing groups, the graphene oxide ligands being capable of cross-linking reaction under light irradiation; The graphene oxide ligand comprises a first coordination group, a first linking group and a first cross-linking group connected in sequence through chemical bonds, the first coordination group being combined with the oxygen-containing group, the first cross-linking group being used for cross-linking reaction under light irradiation; The oxygen-containing group is at least one of an epoxy group, a hydroxyl group, a carboxyl group and a carbonyl group; The first coordination group is an amino group, a polyamino group, a hydroxyl group, a polyhydroxyl group, a mercapto group, a polysulfide group, a sulfide group, a phosphine group or an oxophosphine group; said first linking group is methylene, C 2-8 a straight alkyl chain of 1 to 8 C atoms, an alkyl chain with a branched main chain of 2 to 8 C atoms, a tert-butylphenyl group, a methoxy group or a n-butyloxy group; The first cross-linking group is a double bond group, a triple bond group, an epoxy group, an amino group, a hydroxyl group or a mercapto group.

2. The display device according to claim 1, wherein The double bond group is an olefin group, an ester group, an aldehyde group, a carbonyl group or an azido group.

3. The display device according to claim 1, wherein The triple bond group is an alkyne group or a cyano group.

4. The display device according to claim 1, wherein The epoxy group is an oxirane group, an epoxypropane group, an epoxybutane group or an epoxy pentane group.

5. The display device according to claim 1, wherein The graphene oxide ligand is selected from one of the following compounds:

6. The display device according to claim 1, wherein The graphene oxide film is provided with several graphene oxide films, and each of the graphene oxide films is provided one-to-one with a sub-pixel of different colors of the display device, and the cross-linking degree of the graphene oxide ligands in the same graphene oxide film is greater than the cross-linking degree of the graphene oxide ligands between adjacent graphene oxide films.

7. The display device of claim 1, wherein The display device is a QLED electroluminescent device, and the quantum dot film is used as a quantum dot light-emitting layer of the QLED electroluminescent device.

8. The display device of claim 7, wherein, The quantum dot film comprises quantum dot bodies and quantum dot ligands combined on the quantum dot bodies, and the quantum dot ligands are cross-linked and combined with the graphene oxide ligands.

9. The display device of claim 8, wherein, Further comprising an electron transport layer provided adjacent to the quantum dot light-emitting layer, the electron transport layer comprising zinc oxide and zinc oxide ligands combined on the zinc oxide, and the quantum dot ligands are cross-linked and combined with the zinc oxide ligands.

10. The display device according to claim 1, wherein The display device comprises an electroluminescent device, the quantum dot film and the graphene oxide film provided in sequence, and the quantum dot film is used as a light conversion layer of the display device.

11. The display device of claim 10, wherein, The electroluminescent device is an OLED or a MicroLED.

12. The display device of claim 11, wherein The electroluminescent device is a blue light source, and the quantum dot film comprises a red light conversion quantum dot film and a green light conversion quantum dot film; or The electroluminescent device is a white light source, and the quantum dot film comprises a red light conversion quantum dot film, a green light conversion quantum dot film and a blue light conversion quantum dot film.

13. A method for producing a display device, characterized by The method comprises: coating a quantum dot solution to form a quantum dot film; spin coating chemically modified graphene oxide on the quantum dot film; and cross-linking and combining the graphene oxide ligands and the quantum dot ligands under light irradiation. Exposing a preset region of the quantum dot film according to a patterning requirement, so that in the exposed region, the chemically modified graphene oxide is crosslinked to form a dense graphene oxide film; Developing, so that outside the exposed region, the chemically modified graphene oxide and the quantum dot film are removed; The chemically modified graphene oxide comprises a graphene oxide body and a graphene oxide ligand combined on the graphene oxide body, the graphene oxide body has an oxygen-containing group formed thereon, the graphene oxide ligand is combined on the oxygen-containing group, and the graphene oxide ligand can undergo a crosslinking reaction under light irradiation; The graphene oxide ligand comprises a first coordination group, a first linking group and a first crosslinking group connected in sequence by chemical bonds, the first coordination group is combined with the oxygen-containing group, and the first crosslinking group is used for undergoing a crosslinking reaction under light irradiation; The oxygen-containing group is at least one of an epoxy group, a hydroxyl group, a carboxyl group and a carbonyl group; The first coordination group is an amino group, a polyamino group, a hydroxyl group, a polyhydroxyl group, a mercapto group, a polymercapto group, a sulfide group, a polysulfide group, a phosphine group or an oxygen phosphine group; said first linking group is methylene, C 2-8 a straight alkyl chain of 1 to 8 C atoms, an alkyl chain with a branched main chain of 2 to 8 C atoms, a tert-butylphenyl group, a methoxy group or a n-butyloxy group; The first crosslinking group is a double bond group, a triple bond group, an epoxy group, an amino group, a hydroxyl group or a mercapto group.

14. The method of claim 13, wherein, The double bond group is an olefin group, an ester group, an aldehyde group, a carbonyl group or an azido group.

15. The preparation method according to claim 13, characterized in that, The triple bond group is an alkyne group or a cyano group.

16. The method of claim 13, wherein, The epoxy group is an oxirane group, an oxetane group, a butylene oxide group or a pentylene oxide group.

17. The method of claim 13, wherein, The graphene oxide ligand is selected from a compound of one of the following:

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