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

Abstract

The present disclosure provides a kind of quantum dot ligand, quantum dot-ligand system and quantum dot material, belong to display technical field.The quantum dot ligand includes X group, Y group and Z group, wherein the Y group is used to provide at least two connection sites, at least one connection site is used to connect with X, and the remaining connection site is used to connect with the Z group;The X group is a coordination group, is used to form coordination bond with quantum dot surface;The Z group is saturated 3-5 membered heterocyclic group containing O or S.Saturated 3-5 membered heterocyclic group containing O or S can be assisted by the action of photoacid generator, and ring-opening reaction is carried out, so that crosslinking occurs between quantum dot-ligand unit, thereby providing the basis for quantum dot film layer to form using photolithography process.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a quantum dot ligand, a quantum dot-ligand system, and quantum dot materials. Background Technology

[0002] With the advancement of quantum dot fabrication technology, the stability and luminous efficiency of quantum dots have been continuously improved, leading to in-depth research on quantum dot light-emitting diodes (QLEDs). The application prospects of QLEDs in the display field are becoming increasingly bright. However, the efficiency of QLEDs has not yet reached mass production levels. One important reason is that a breakthrough in high-resolution patterning technology for QLEDs has not yet been achieved.

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

[0004] The information disclosed in the background section is only for enhancing the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a quantum dot ligand, a quantum dot-ligand system, and a quantum dot material, which provides a basis for the formation of quantum dot films using photolithography.

[0006] To achieve the above-mentioned objectives, the present disclosure adopts the following technical solution:

[0007] According to a first aspect of this disclosure, a quantum dot ligand is provided, the quantum dot ligand comprising an X group, a Y group, and a Z group.

[0008] The Y group is used to provide at least two connection sites, wherein at least one connection site is used to connect with X, and the remaining connection sites are used to connect with the Z group;

[0009] The X group is a coordinating group used to form coordinate bonds with the surface of the quantum dot.

[0010] The Z group is a saturated 3-5 membered heterocyclic group containing O or S.

[0011] In one exemplary embodiment of this disclosure, the Z group in the quantum dot ligand is used to undergo a ring-opening and cross-linking reaction with adjacent quantum dot ligands under external influence.

[0012] In one exemplary embodiment of this disclosure, the Y group includes at least one linking group, the linking group providing at least two linking sites, one of the linking sites of the linking group being used for linking with the Z group, the linking group being selected from alkylene groups having 2-12 carbon atoms.

[0013] In one exemplary embodiment of this disclosure, the Y group further includes a carrier transport regulating group, which is connected between the linking group and the Z group.

[0014] In one exemplary embodiment of this disclosure, the carrier transport regulating group is selected from aniline structures, triphenylamine structures, or carbazole structures.

[0015] In one exemplary embodiment of this disclosure, the Y group further includes a dissolving group, which is connected between the linking group and the Z group, and the dissolving group is selected from the group comprising... The structure.

[0016] In one exemplary embodiment of this disclosure, the coordinating group is selected from amino, carboxylic acid, mercapto, phosphin, phosphoxy, or a saturated heterocyclic group containing a disulfide bond.

[0017] In one exemplary embodiment of this disclosure, the Z group is selected from epoxy groups.

[0018] In one exemplary embodiment of this disclosure, the quantum dot ligand is selected from the group consisting of the following structures:

[0019]

[0020] R1, R2, R3, and R4 are each independently selected from amino, carboxylic acid, mercapto, phosphin, phosphoxy, or...

[0021] Ar1 is selected from those containing aniline, carbazolyl, or... The structure, R5 is selected from

[0022] n1, n2, and n3 are each independently selected from any integer between 2 and 8.

[0023] In one exemplary embodiment of this disclosure, the quantum dot ligand is selected from the group consisting of the following structures:

[0024]

[0025] Where R is selected from

[0026] n1, n2, and n3 are each independently selected from any integer between 2 and 8.

[0027] According to a second aspect of this disclosure, a quantum dot-ligand system is provided, comprising a quantum dot, a photoacidinogen, and the quantum dot ligand described in the first aspect.

[0028] In one exemplary embodiment of this disclosure, the photoacid generator is selected from thionium salts, triazines, sulfonates, or diazonium salts.

[0029] According to a third aspect of this disclosure, a quantum dot-ligand material is provided, comprising at least two quantum dot-ligand units, each quantum dot-ligand unit comprising a quantum dot and the quantum dot ligand described in the first aspect, wherein the quantum dot-ligand units are cross-linked and bonded to each other via the Z-group to form a network structure.

[0030] According to a fourth aspect of this disclosure, a method for preparing a quantum dot film is provided, comprising:

[0031] A quantum dot-ligand solution is provided, wherein the quantum dot-ligand solution is a mixed solution comprising quantum dots, a photoacidifier, and a quantum dot ligand as described in the first aspect;

[0032] The quantum dot-ligand solution is coated onto a substrate and exposed to light, causing the photoacid generator to produce hydrogen ions and catalyze the ring-opening and cross-linking reaction of the Z group.

[0033] The quantum dot film is formed by performing a development process.

[0034] According to a fifth aspect of this disclosure, a quantum dot light-emitting device is provided, comprising an anode, a cathode, and a functional layer disposed between the anode and the cathode, the functional layer comprising a quantum dot light-emitting layer comprising a quantum dot-ligand material as described in the third aspect.

[0035] In one exemplary embodiment of this disclosure, the functional layer further includes a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0036] According to a sixth aspect of this disclosure, a method for fabricating a quantum dot light-emitting device is provided, comprising:

[0037] A green quantum dot-ligand solution is provided, wherein the green quantum dot-ligand solution is a mixed solution comprising green quantum dots, a photoacidifier, and a quantum dot ligand as described in the first aspect;

[0038] A blue quantum dot-ligand solution is provided, wherein the blue quantum dot-ligand solution is a mixed solution comprising blue quantum dots, a photoacidinogen, and a quantum dot ligand as described in the first aspect;

[0039] A red quantum dot-ligand solution is provided, wherein the red quantum dot-ligand solution is a mixed solution comprising red quantum dots, a photoacidifier, and a quantum dot ligand as described in the first aspect;

[0040] The green quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form green sub-pixels.

[0041] The blue quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form blue sub-pixels.

[0042] The red quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form red sub-pixels.

[0043] According to a seventh aspect of this disclosure, a display device is provided, comprising a quantum dot light-emitting device as described in the fifth aspect.

[0044] The quantum dot ligands disclosed herein contain coordinating groups and saturated 3-5 membered heterocyclic groups containing O or S. The coordinating groups can form coordinate bonds with the quantum dots, thereby forming quantum dot-ligand units. The saturated 3-5 membered heterocyclic groups containing O or S can undergo ring-opening reactions with the assistance of photoacidifying agents, causing cross-linking between the quantum dot-ligand units, thus providing a basis for the formation of quantum dot films using photolithography. Attached Figure Description

[0045] The above and other features and advantages of this disclosure will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0046] Figure 1 This is a schematic diagram of the structure of a green quantum dot ligand solution coated on a substrate in an exemplary embodiment of this disclosure;

[0047] Figure 2 This is a schematic diagram of forming a green light subpixel structure in an exemplary embodiment of this disclosure;

[0048] Figure 3 This is a schematic diagram of the structure of a blue quantum dot ligand solution coated on a substrate in an exemplary embodiment of this disclosure;

[0049] Figure 4 This is a schematic diagram of forming a blue light subpixel structure in an exemplary embodiment of this disclosure;

[0050] Figure 5 This is a schematic diagram of the structure of a red quantum dot ligand solution coated on a substrate in an exemplary embodiment of this disclosure;

[0051] Figure 6 This is a schematic diagram of forming a red light subpixel structure in an exemplary embodiment of this disclosure.

[0052] The annotations for the main components in the diagram are explained below:

[0053] 1-Substrate; 21-Green quantum dot film; 211-Green subpixel; 22-Blue quantum dot film; 221-Blue subpixel; 23-Red quantum dot film; 231-Red subpixel. Detailed Implementation

[0054] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are set forth to give a full understanding of embodiments of this disclosure.

[0055] For clarity, the thickness of regions and layers may be exaggerated in the figures. The same reference numerals in the figures denote the same or similar structures, and therefore their detailed descriptions will be omitted.

[0056] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring the main technical concept of this disclosure.

[0057] When a structure is "on" other structures, it may mean that the structure is integrally formed on other structures, or that the structure is "directly" set on other structures, or that the structure is "indirectly" set on other structures through another structure.

[0058] The terms “a,” “one,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and that other elements / components / etc. may exist in addition to those listed. The terms “first” and “second” are used only as markers and are not a limitation on the number of objects.

[0059] Quantum dots (QDs) are composed of zinc, cadmium, selenium, and sulfur atoms. They are nanomaterials with crystal diameters between 2 and 10 nm. They have unique photoelectric properties. When stimulated by photoelectric signals, they emit pure monochromatic light of various colors depending on the diameter of the quantum dot, and can change the color of the light source.

[0060] In related technologies, quantum dots, due to their susceptibility to heat and moisture, cannot be deposited using the same vapor deposition method as self-emissive OLEDs and can currently only be printed using inkjet printing. However, achieving high resolution through inkjet printing is difficult.

[0061] This disclosure provides a quantum dot ligand and a quantum dot-ligand system containing the quantum dot ligand. This system exhibits photosensitive properties and can directly form red, green, and blue sub-pixels through photolithography, avoiding the technical difficulties of improving resolution, such as the need for higher-precision printheads, as seen in inkjet printing. The quantum dot ligand provided in this disclosure facilitates the production of high-resolution QLED products, simplifies fabrication processes, improves process yield, and significantly increases the utilization rate of quantum dot materials, thus laying the foundation for the large-scale industrialization of QLEDs.

[0062] This disclosure provides a quantum dot ligand comprising an X group, a Y group, and a Z group.

[0063] Wherein, the Y group is used to provide at least two linkage sites, wherein at least one linkage site is used to link with the X group, and the remaining linkage sites are used to link with the Z group;

[0064] The X group is a coordinating group used to form coordinate bonds with the quantum dot surface;

[0065] The Z group is a saturated 3-5 membered heterocyclic group containing O or S.

[0066] The quantum dot ligands disclosed herein contain coordinating groups and saturated 3-5 membered heterocyclic groups containing O or S. The coordinating groups can form coordinate bonds with the quantum dots, thereby forming quantum dot-ligand units. The saturated 3-5 membered heterocyclic groups containing O or S can undergo ring-opening reactions with the assistance of photoacidifying agents, causing cross-linking between the quantum dot-ligand units, thus providing a basis for the formation of quantum dot films using photolithography.

[0067] Quantum dots (QDs) are inorganic semiconductor nanoparticles with sizes ranging from 1 to 10 nm, synthesized via solution methods. This size is approximately equal to or smaller than the exciton Bohr radius of the particle. Due to their small size and large specific surface area, quantum dots are prone to aggregation, and they also exhibit numerous surface defects. Therefore, in applications, the surface of quantum dots is often coated with organic surface ligands, which serve both a protective function and improve the solubility of the quantum dots in solution. The migration of charge carriers (electrons and holes) within quantum dots is confined to their interior, giving them unique optical and electrical properties. Due to their unique size-dependent nature, the light absorption and light emission properties of quantum dots can be easily tuned by controlling the particle size, shape, or surface structure.

[0068] Quantum dots are typically coated with an organic ligand. These surface ligands not only determine the solubility and surface chemical functionality of quantum dots, but also significantly affect their fluorescence quantum yield and electrical properties.

[0069] In this disclosure, a linking site refers to a group that provides a chemical bond that can be used to link with other groups. A Y group may have two or more linking sites, and different linking sites can be linked with different groups.

[0070] The Y group provides at least two linkage sites, at least one of which is used to connect with the X group, and the remaining linkage sites are used to connect with the Z group. In this description, the linkage site is used to connect with either the X or Z group; specifically, the linkage site can connect directly to the X or Z group, or indirectly to the X or Z group through an intermediate group. When multiple linkage sites are connected to the X group, the quantum dot ligand structure has multiple X groups. Similarly, when multiple linkage sites are connected to the Z group, the quantum dot ligand structure has multiple Z groups. The X and Z groups are terminal groups in the quantum dot ligand structure.

[0071] The ligands are connected to the surface of the quantum dot via coordination bonds, thereby introducing the quantum dot ligands of this disclosure onto the quantum dot.

[0072] The Z group is a saturated 3- to 5-membered heterocyclic group containing O or S. Specifically, it can be a saturated 3-membered heterocyclic group, a saturated 4-membered heterocyclic group, or a saturated 5-membered heterocyclic group.

[0073] In some embodiments of this disclosure, the Z group is a photosensitive group, and the Z group in the quantum dot ligand is used to open the ring and undergo a cross-linking reaction with the adjacent quantum dot ligand under external influence.

[0074] In some embodiments of this disclosure, the Y group includes at least one linking group, the linking group providing at least two linking sites, one of the linking sites being for connection with the Z group, the linking group being selected from alkylene groups having 2-12 carbon atoms.

[0075] The Y group may include one or more linking groups. When the Y group contains only one linking group, the linking group has two linkage sites, one for linking with the coordinating group, i.e., the X group, and the other for linking with the Z group.

[0076] When group Y contains multiple linking groups, these linking groups may be the same or different. One linking site in these linking groups is used to connect with group Z, and the remaining linking sites are used to connect with group X or other linking groups. At least one linking site in at least one of the linking groups is used to connect with group X. For example, when group Y contains multiple linking groups, one linking group can be the parent chain, and the others can be branches. The parent chain linking group has multiple linking sites, where at least one linking site is used to connect with group X, at least one linking site is used to connect with group Z, and the remaining linking sites are used to connect with branched linking groups. A branched linking group can have two linking sites, where one linking site is used to connect with the parent chain linking group, and the other linking site is used to connect with group Z. In this case, the group Y formed by the connection of multiple linking groups exhibits a branched dendritic molecule.

[0077] The linking group is selected from alkylene groups having 2-12 carbon atoms. Specifically, the alkylene group can have 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms. The alkylene group can be a straight-chain alkylene group or a branched alkylene group. Examples include ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, etc.

[0078] In some embodiments of this disclosure, the Y group further includes a carrier transport regulating group, which is connected between the linking group and the Z group. The carrier transport regulating group is disposed in the quantum dot ligand to subsequently form a quantum dot-ligand material with strong carrier transport capability.

[0079] The carrier transport regulating group is selected from aniline, triphenylamine, or carbazole structures. Among them, triphenylamine and carbazole structures are favorable for hole transport.

[0080] In some embodiments of this disclosure, the Y group further includes a dissolving group, which is connected between the linking group and the Z group, and the dissolving group is selected from the group comprising... The structure of.

[0081] When the Y group includes a carrier transport regulating group, the dissolving group can be attached between the linking group and the carrier transport regulating group, or between the carrier transport regulating group and the Z group (photosensitive group). Incorporating the dissolving group into the quantum dot ligands disclosed herein facilitates both the synthesis of the quantum dot ligands and increases their solubility.

[0082] In some embodiments of this disclosure, the coordinating group is selected from amino, carboxylic acid, mercapto, phosphin, phosphoxy, or a saturated heterocyclic group containing a disulfide bond. The saturated heterocyclic group containing a disulfide bond can be a saturated five-membered or six-membered ring. For example, when the coordinating group is selected from a mercapto group, the sulfur atom in the mercapto group forms a coordinate bond with the surface of the ZnSe / CdSe quantum dot. When the coordinating group is selected from an amino group, the nitrogen atom in the amino group forms a coordinate bond with the surface of the ZnSe / CdSe quantum dot. When the coordinating group is selected from a saturated heterocyclic group containing a disulfide bond, the disulfide bond is broken, and the sulfur atom forms a coordinate bond with the surface of the ZnSe / CdSe quantum dot.

[0083] In some embodiments of this disclosure, the Z group is preferably an epoxy group. The epoxy group is a three-membered ring, which is easier to synthesize and has a faster ring-opening polymerization rate, and does not require heating.

[0084] In some embodiments of this disclosure, the quantum dot ligands are selected from the group consisting of the following structures:

[0085]

[0086] R1, R2, R3, and R4 are each independently selected from amino, carboxylic acid, mercapto, phosphin, phosphoxy, or...

[0087] Ar1 is selected from those containing aniline, carbazolyl, or... The structure, R5 is selected from

[0088] n1, n2, and n3 are each independently selected from any integer between 2 and 8.

[0089] In this embodiment, the triphenylamine group has strong rigidity, resulting in poor solubility, while the R5 group has strong solubility. Connecting R5 to the triphenylamine group helps to improve the solubility of the triphenylamine structure.

[0090] In this disclosure, the description “each independently selected” is interpreted broadly. It can mean either that the specific options expressed by the same symbol in different groups do not affect each other, or that the specific options expressed by the same symbol in the same group do not affect each other.

[0091] In some embodiments of this disclosure, the quantum dot ligands are selected from the group consisting of the following structures:

[0092]

[0093] Where R is selected from

[0094] n1, n2, and n3 are each independently selected from any integer between 2 and 8.

[0095] In this disclosure, the epoxy group has sufficient solubility in polar to highly polar solvents such as PGMEA (propylene glycol methyl ether acetate). Therefore, the epoxy group of this disclosure can serve not only as a photosensitive group but also as a dissolving group, and it can interact with solvents containing... The structural connections, while ensuring the photosensitivity of the quantum dot ligands disclosed herein, can jointly enhance the solubility of the quantum dot ligands.

[0096] This disclosure also provides a quantum dot-ligand system, comprising a quantum dot, a photoacid generator, and the aforementioned quantum dot ligand.

[0097] The inorganic portion of quantum dots disclosed herein includes, but is not limited to, quantum dots such as CdS, CdSe, ZnSe, InP, PbS, CsPbCl3, CsPbBr3, CsPhI3, CdS / ZnS, CdSe / ZnS, ZnSe, InP / ZnS, PbS / ZnS, CsPbCl3 / ZnS, CsPbBr3 / ZnS, CsPhI3 / ZnS, ZnSe, and ZnTeSe / ZnSe; and also includes nanoparticle materials such as ZnO, ZnMgO, ZnAlO, and ZnLiO.

[0098] Photoacids are photosensitizing compounds that decompose under light to produce acids (H+). + The photoacid generator is selected from thionium salts, triazines, sulfonates, or diazonium salts. Specifically, the photoacid generator is selected from triphenylthionium hexafluoroantimonyate, (4,6)-bis(trichloromethyl)-1,3,5-triazine derivatives, N-p-toluenesulfonyloxyphthalimide, and diazonium fluoroborate.

[0099] In this quantum dot-ligand system, quantum dots and quantum dot ligands can be linked by coordinate bonds to form quantum dot-ligand units, and photoacids can decompose under light irradiation to produce acid (H+). + This promotes the ring-opening of saturated heterocyclic groups containing O or S in the quantum dot-ligand units, and cross-linking between quantum dot-ligand units.

[0100] This disclosure also provides a quantum dot-ligand material comprising at least two quantum dot-ligand units, each quantum dot-ligand unit comprising a quantum dot and the aforementioned quantum dot ligand, wherein the quantum dot-ligand units are cross-linked and bonded to each other via Z-groups to form a network structure.

[0101] This disclosure also provides a method for preparing a quantum dot film, including:

[0102] A quantum dot-ligand solution is provided, wherein the quantum dot-ligand solution is a mixed solution comprising quantum dots, a photoacidifier, and the aforementioned quantum dot ligands;

[0103] A quantum dot-ligand solution was coated onto a substrate and exposed to light, causing the photoacid generator to produce hydrogen ions and catalyze the ring-opening and cross-linking reaction of the Z groups.

[0104] The development process is carried out to form a quantum dot film.

[0105] This disclosure also provides a quantum dot light-emitting device, including an anode, a cathode, and a functional layer disposed between the anode and the cathode, the functional layer including a quantum dot light-emitting layer, the quantum dot light-emitting layer including the aforementioned quantum dot-ligand material.

[0106] The functional layers also include a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

[0107] In one specific embodiment of this disclosure, a quantum dot light-emitting device may include an anode, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a cathode, which are stacked sequentially.

[0108] Optionally, the anode comprises anode materials, preferably those with a high work function that facilitates hole injection into the functional layer. Specific examples of anode materials include: metals such as nickel, platinum, vanadium, chromium, copper, zinc, and gold, or alloys thereof; and metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Preferably, a transparent electrode comprising indium tin oxide (ITO) as the anode is included.

[0109] Optionally, the hole transport layer may include one or more hole transport materials, which may be selected from carbazole polymers, carbazole-linked triarylamine compounds, or other types of compounds. This disclosure does not impose any special limitations on these materials.

[0110] The electron transport layer can be a single-layer structure or a multi-layer structure, and it can include one or more electron transport materials. The electron transport materials can be selected from benzimidazole derivatives, oxadiazole derivatives, quinoxaline derivatives or other electron transport materials. This disclosure does not make any special limitations in this regard.

[0111] Optionally, the cathode may comprise a cathode material having a small work function that facilitates electron injection into the functional layers. Specific examples of cathode materials include, but are not limited to, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead or alloys thereof; or multilayer materials such as LiF / Al, Liq / Al, LiO2 / Al, LiF / Ca, LiF / Al, and BaF2 / Ca.

[0112] Optionally, a hole injection layer may be disposed between the anode and the hole transport layer to enhance the ability to inject holes into the hole transport layer. An electron injection layer may be disposed between the cathode and the electron transport layer to enhance the ability to inject electrons into the electron transport layer.

[0113] This disclosure also provides a method for fabricating a quantum dot light-emitting device, comprising the following steps:

[0114] A green quantum dot-ligand solution is provided, wherein the green quantum dot-ligand solution is a mixed solution comprising green quantum dots, photoacidifiers and the aforementioned quantum dot ligands;

[0115] A blue quantum dot-ligand solution is provided, wherein the blue quantum dot-ligand solution is a mixed solution comprising blue quantum dots, a photoacid generator, and the aforementioned quantum dot ligands;

[0116] A red quantum dot-ligand solution is provided, wherein the red quantum dot-ligand solution is a mixed solution comprising red quantum dots, a photoacidifier and the aforementioned quantum dot ligand;

[0117] A green quantum dot-ligand solution is coated onto a substrate, and then exposed and developed to form green sub-pixels;

[0118] A blue quantum dot-ligand solution is coated onto a substrate, and then exposed and developed to form blue sub-pixels;

[0119] A red quantum dot-ligand solution is coated onto a substrate, and then exposed and developed to form red sub-pixels.

[0120] This disclosure also provides a display device, including the aforementioned quantum dot light-emitting device. The display device disclosed herein can be an electronic device such as a mobile phone, tablet computer, or television, which will not be listed here individually.

[0121] Example of quantum dot ligand synthesis:

[0122] (1) Quantum dot ligands

[0123] Taking n1=3 as an example

[0124]

[0125] Thioctic acid (CAS 62-46-4; 20.6 g, 100 mmol) was dissolved in 100 mL of anhydrous diethyl ether with allyl alcohol (prop-2-en-1-ol; CAS 107-18-6; 5.81 g, 100 mmol) and 4-dimethylaminopyridine (DMAP; CAS 1122-58-3; 1.22 g, 10 mmol), and the system was cooled to 0 °C. 1,3-dicyclohexylcarbodiimide (DCC; CAS 538-75-0; 22.7 g, 110 mmol) was dissolved in 50 mL of anhydrous diethyl ether, and the precipitate was slowly added at 0 °C. After stirring overnight at room temperature, the precipitate was removed by filtration; the filtrate was concentrated under low pressure and purified by silica gel column chromatography to give product 1 (22.1 g, 90% yield). 1 H NMR (400MHz, CDCl3): δ=1.25(2H), 1.51(2H), 1.66-1.96(4H), 2.32-2.34(3H), 4.69(1H), 5.31-5.32(2H), 6.05(1H)

[0126] Product 1 (12.3 g, 50 mmol) and 3-chloroperoxybenzoic acid (mCPBA, CAS 937-14-4; 9.49 g, 55 mmol) were dissolved in 200 mL of dichloromethane and stirred at 0 °C for 2 hours. The reaction was then terminated by adding 1 M sodium hydroxide and extracted with brine. The organic phase was collected, dried over anhydrous sodium sulfate, concentrated, and separated by column chromatography to obtain product 2 (11.1 g, 85% yield). 1 ¹H NMR (400MHz, CDCl₃): δ=1.25(2H), 1.51(2H), 1.66-1.96(4H), 2.32-2.34(3H), 3.13(1H), 4.07(1H), 4.32(1H) (2) Quantum dot ligands

[0127] Synthesize using the following formula:

[0128]

[0129] (3) Quantum dot ligands

[0130] Synthesize using the following formula:

[0131]

[0132] (4) Quantum dot ligands

[0133] Synthesize using the following formula:

[0134]

[0135] (5) Quantum dot ligands

[0136] Synthesize using the following formula:

[0137]

[0138] The above-described quantum dot ligand synthesis formulas and methods are merely illustrative of the synthesis methods for quantum dot coordination disclosed herein. Those skilled in the art can refer to the above methods to synthesize other quantum dot ligands protected by this disclosure.

[0139] Photolithography process for forming quantum dot films

[0140] (1) Provide a quantum dot-ligand solution, which is a mixed solution including quantum dots, photoacids and quantum dot ligands. The specific steps are as follows:

[0141] The quantum dots CdSe / ZnSe with oleic acid ligands were dissolved in toluene solution, and the quantum dot ligands provided in this disclosure, as shown in Table 1, were added. After stirring for 4-12 hours, the mixture was precipitated / dissolved three times with ethyl acetate / toluene, precipitated with ethyl acetate, dried, and dissolved in toluene to obtain quantum dots with the quantum dot ligands of this disclosure, as shown in Table 2.

[0142] Subsequently, a photoacidifying agent is added to the solution at a concentration of 1%-5% by mass. In this step, green quantum dot-ligand solutions, blue quantum dot-ligand solutions, and red quantum dot-ligand solutions can be prepared by controlling the size of the quantum dots.

[0143] Table 1

[0144]

[0145] Quantum dots with quantum dot ligands as disclosed herein are as follows:

[0146] Table 2

[0147]

[0148]

[0149] 2) A quantum dot-ligand solution is coated onto a substrate and exposed to allow the photoacid generator to produce hydrogen ions, which catalyze a Z-ring-opening crosslinking reaction. Development is then performed to form a quantum dot film. The specific steps include:

[0150] like Figures 1 to 2 As shown, a green quantum dot-ligand solution is coated on substrate 1 to form a green quantum dot film layer 21. A first patterning (photo mask) process is then applied, followed by overall exposure to ultraviolet light. After exposure, the substrate is heated in a 90°C environment for 120 seconds (to promote the complete deprotection reaction of Boc). Subsequently, one or more mixed solvents of chloroform, toluene, chlorobenzene, tetrahydrofuran, n-hexane, n-heptane, and n-octane are used as developers for rinsing and development. After development, the substrate is again heated in a 90°C environment for 120 seconds to remove the developers, forming green subpixels 211.

[0151] like Figures 3 to 4 As shown, a blue quantum dot-ligand solution is coated to form a blue quantum dot film 22, a second photo mask is added, and the whole is exposed with ultraviolet light, followed by development and fixing to form blue light sub-pixels 221;

[0152] like Figures 5 to 6 As shown, a red quantum dot-ligand solution is finally coated to form a red quantum dot film 23. A third Photo Mask is then added, and the entire film is exposed to ultraviolet light. After development and fixing, red subpixels 231 are formed.

[0153] Taking ligand 1 in Table 1 as an example, the changes in the quantum dots after exposure are shown below:

[0154]

[0155] The changes in quantum dots after exposure to other ligands can be found in the above description.

[0156] Example of display panel fabrication

[0157] The display panel includes a quantum dot light-emitting device, which includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked sequentially.

[0158] The specific steps involved in the fabrication of the display panel are as follows:

[0159] The transparent substrate was cleaned using standard methods, followed by the sequential deposition and patterning of the following layers: gate metal Mo 200 nm; gate dielectric SiO2 150 nm; active layer IGZO 40 nm (patterned); source / drain metal Mo 200 nm (patterned); passivation layer SiO2 300 nm (patterned); pixel electrode ITO 40 nm (patterned); and finally, an acrylic material was spin-coated, photolithographically etched, and cured to form a pixel boundary layer of approximately 1.5 μm, thus forming the TFT backplane.

[0160] Before fabricating quantum dot light-emitting devices (QD-LEDs), the surface of the TFT backplane is treated with plasma.

[0161] Hole injection layer and hole transport layer are prepared by spin coating process, such as spin coating PEDOT (poly(3,4-ethylenedioxythiophene)), PSS (polystyrene sulfonic acid) and TFB, etc.; the overall thickness is 50-100nm.

[0162] The quantum dot film layer is formed using the above-mentioned photolithography process, specifically including: coating a green quantum dot-ligand solution, adding a first photo mask, exposing the entire layer with ultraviolet light, and then developing and fixing to form green sub-pixels; then coating a blue quantum dot-ligand solution, adding a second photo mask, exposing the entire layer with ultraviolet light, and then developing and fixing to form blue sub-pixels; finally coating a red quantum dot-ligand solution, adding a third photo mask, exposing the entire layer with ultraviolet light, and then developing and fixing to form red sub-pixels.

[0163] Spin coating or vapor deposition can be used to form electron transport and electron injection layers, such as ZnO nanoparticles.

[0164] A thin metal layer of cathode is deposited by vapor deposition. The cathode can be an Al layer or similar material, with a thickness of approximately 500-1000 nm. After vapor deposition, the cathode is encapsulated and cut to complete the fabrication of the entire display panel.

[0165] The AMQLED device can emit light from the bottom, and the smallest subpixel area that can be fabricated is 10-30 micrometers, with a display panel size of approximately 300-800 ppi.

[0166] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps, such as omitting certain steps, combining multiple steps into one step, and / or breaking down one step into multiple steps, should all be considered part of this disclosure.

[0167] It should be understood that this disclosure is not limited to the detailed structure and arrangement of the components presented in this specification. This disclosure is capable of other embodiments and can be implemented and performed in various ways. The foregoing variations and modifications fall within the scope of this disclosure. It should be understood that this disclosure, as disclosed and defined in this specification, extends to all alternative combinations of two or more individual features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of this disclosure. The embodiments described in this specification illustrate the best known mode for implementing this disclosure and will enable those skilled in the art to utilize this disclosure.

Claims

1. A quantum dot ligand, characterized in that, The quantum dot ligands include X groups, Y groups, and Z groups. The Y group is used to provide at least two connection sites, wherein at least one connection site is used to connect with X, and the remaining connection sites are used to connect with the Z group; The X group is a coordinating group used to form coordinate bonds with the surface of the quantum dot. The Z group is a saturated 3-5 membered heterocyclic group containing O or S; The Y group includes at least one linking group, which provides at least two linking sites. One of the linking sites is used to link with the Z group. The linking group is selected from alkylene groups having 2-12 carbon atoms. The Y group also includes a carrier transport regulating group, which is connected between the linking group and the Z group.

2. The quantum dot ligand according to claim 1, characterized in that, The Z group in the quantum dot ligand is used to open the ring and crosslink with adjacent quantum dot ligands under external influence.

3. The quantum dot ligand according to claim 1, characterized in that, The carrier transport regulating group is selected from aniline, triphenylamine, or carbazole structures.

4. The quantum dot ligand according to claim 1, characterized in that, The Y group further includes a dissolving group, which is connected between the linking group and the Z group, and the dissolving group is selected from the group comprising... or The structure.

5. The quantum dot ligand according to claim 1, characterized in that, The coordinating group is selected from amino, carboxylic acid, mercapto, phosphin, phosphoxy, or saturated heterocyclic groups containing disulfide bonds.

6. The quantum dot ligand according to claim 1, characterized in that, The Z group is selected from epoxy groups.

7. The quantum dot ligand according to claim 1, characterized in that, The quantum dot ligands are selected from the group consisting of the following structures: ； Wherein, R3 is selected from amino, carboxylic acid, mercapto, phosphino, phosphoxy, or... ; Ar1 is selected from those containing aniline, carbazolyl, or... The structure, R5 is selected from or ; n1 and n3 are each independently selected from any integer between 2 and 8.

8. The quantum dot ligand according to claim 1, characterized in that, The quantum dot ligands are selected from the group consisting of the following structures: ； Where R is selected from or ; n1 and n3 are each independently selected from any integer between 2 and 8.

9. A quantum dot-ligand system, characterized in that, Including quantum dots, photoacid generators, and quantum dot ligands as described in any one of claims 1-8.

10. The quantum dot-ligand system according to claim 9, characterized in that, The photoacid generator is selected from thioonium salts, triazines, sulfonates, or diazonium salts.

11. A quantum dot-ligand material, characterized in that, It includes at least two quantum dot-ligand units, each quantum dot-ligand unit comprising a quantum dot and a quantum dot ligand as described in any one of claims 1-8, wherein the quantum dot-ligand units are cross-linked and bonded to each other through the Z-group to form a network structure.

12. A method for preparing a quantum dot film, characterized in that, include: A quantum dot-ligand solution is provided, wherein the quantum dot-ligand solution is a mixed solution comprising quantum dots, a photoacidifier, and a quantum dot ligand as described in any one of claims 1-8; The quantum dot-ligand solution is coated onto a substrate and exposed to light, causing the photoacid generator to produce hydrogen ions and catalyze the ring-opening and cross-linking reaction of the Z group. The quantum dot film is formed by performing a development process.

13. A quantum dot light-emitting device, characterized in that, It includes an anode, a cathode, and a functional layer disposed between the anode and the cathode, the functional layer including a quantum dot light-emitting layer, the quantum dot light-emitting layer including the quantum dot-ligand material as described in claim 11.

14. The quantum dot light-emitting device according to claim 13, characterized in that, The functional layer also includes a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

15. A method for fabricating a quantum dot light-emitting device, characterized in that, include: A green quantum dot-ligand solution is provided, wherein the green quantum dot-ligand solution is a mixed solution comprising green quantum dots, a photoacidifier, and a quantum dot ligand as described in any one of claims 1-8; A blue quantum dot-ligand solution is provided, wherein the blue quantum dot-ligand solution is a mixed solution comprising blue quantum dots, a photoacidinogen, and a quantum dot ligand as described in any one of claims 1-8; A red quantum dot-ligand solution is provided, wherein the red quantum dot-ligand solution is a mixed solution comprising red quantum dots, a photoacidinogen, and a quantum dot ligand as described in any one of claims 1-8; The green quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form green sub-pixels. The blue quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form blue sub-pixels. The red quantum dot-ligand solution is coated onto a substrate and then exposed and developed to form red sub-pixels.

16. A display device, characterized in that, Including the quantum dot light-emitting device as described in any one of claims 13-14.

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