Quantum dot material, luminescent device and preparation method thereof

Abstract

The embodiment of the invention provides a quantum dot material, a light-emitting device and a preparation method of the light-emitting device, and relates to the technical field of display. The quantum dot material comprises a quantum dot body and a functional material. The functional material comprises an aromatic amine group and a hydrotropy group. The hydrotropy group is used for increasing the solubility of the functional material in a preset solvent, and the ratio of the mass of the functional material to the mass of the quantum dot body is larger than 0 and smaller than or equal to 0.45. The cross-linked quantum dot material formed by the quantum dot material is used as a light-emitting layer material of a light-emitting device.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a quantum dot material, a light-emitting device, and a method for preparing the same. Background Technology

[0002] Quantum dots (QDs), as novel luminescent materials, possess advantages such as high color purity, high quantum efficiency, tunable emission wavelength, and long lifespan, making them a research hotspot for novel LED (Light Emitting Diode) luminescent materials. Therefore, quantum dot light-emitting diodes (QLEDs) using quantum dot luminescent materials as the luminescent layer have become a major research direction for novel display devices. Summary of the Invention

[0003] The purpose of this disclosure is to provide a quantum dot material, a light-emitting device, and a method for preparing the same, for use in quantum dot light-emitting diodes.

[0004] To achieve the above objectives, the embodiments of this disclosure provide the following technical solutions:

[0005] On one hand, a quantum dot material is provided. The quantum dot material includes a quantum dot matrix and a functional material. The functional material contains aromatic amine groups and solubilizing groups. The solubilizing groups are used to increase the solubility of the functional material in a preset solvent, and the ratio between the mass of the functional material and the mass of the quantum dot matrix is ​​greater than 0 and less than or equal to 0.45.

[0006] With the above configuration, when using quantum dot materials to prepare the light-emitting layer of a QLED light-emitting device, firstly, by including aromatic amine groups in the functional material, the carrier transport performance of the light-emitting layer can be improved by utilizing the aromatic amine groups. Specifically, the nitrogen atoms in the aromatic amine groups have strong electron-donating ability, strong π-π interactions, and good conjugation, resulting in high hole mobility of the functional material. Secondly, the solubilizing groups of the functional material can improve the solubility of the functional material in the preset solvent, allowing the functional material to exist in the quantum dot solution in a free or bonded form to the quantum dot matrix. This allows the quantum dot matrix and the functional material to form a uniform and stable quantum dot solution, enabling the functional material to participate in film formation and facilitating the balancing effect of the functional material on electron and hole mobility. It also weakens the intermolecular interaction forces between any two of the quantum dot matrix, ligand material, and front film material, preventing the quantum dot material from remaining on the surface of the front film after development, thus solving the problem of color crosstalk. Here, the ligand material is, for example, the first ligand material and / or the second functional material described in detail below.

[0007] In some embodiments, the preset solvent comprises ether groups and / or ester groups.

[0008] In some embodiments, the functional material includes a first functional material. The first functional material comprises a first aromatic amine group and a solubilizing group. The first functional material is not connected to the quantum dot bulk.

[0009] In some embodiments, the ratio between the mass of the first functional material and the mass of the quantum dot bulk is in the range of 0 to 0.35.

[0010] In some embodiments, the functional material includes a second functional material. The second functional material comprises a second aromatic amine group, a second coordinating group, and a solubilizing group. The second functional material may be located within the quantum dot matrix.

[0011] In some embodiments, the second coordinating group includes a carboxyl group and / or a thiol group.

[0012] In some embodiments, the second functional material further comprises a second photosensitive group.

[0013] In some embodiments, the quantum dot material further includes a first ligand material. The first ligand material comprises a first photosensitive group. The first ligand material may be ligated into the quantum dot body.

[0014] In some embodiments, when the second functional material comprises a second photosensitive group, the second photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups, and azido groups. When the quantum dot material comprises a first ligand material, the first photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups, and azido groups.

[0015] In some embodiments, when the quantum dot material includes a first ligand material, the ratio between the mass of the first ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45. When the quantum dot material includes a first ligand material and a second functional material, the ratio between the sum of the masses of the first ligand material and the second functional material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45.

[0016] In some embodiments, the functional material includes a third functional material. The third functional material comprises a third aromatic amine group, at least two initiating groups, and a solubilizing group. When the quantum dot material includes a first ligand material, the initiating group is configured to react with a first photosensitive group under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material. When the quantum dot material includes a second functional material, and the second functional material includes a second photosensitive group, the initiating group is configured to react with the second photosensitive group under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material. The solubility of the cross-linked quantum dot material in a predetermined solvent is less than the solubility of the quantum dot material in the predetermined solvent.

[0017] In some embodiments, the initiating group includes a thiol group.

[0018] In some embodiments, the ratio between the mass of the third functional material and the mass of the quantum dot bulk is in the range of 0 to 0.05.

[0019] In some embodiments, the functional material is selected from any of the structures shown in the following general formula (I);

[0020]

[0021] Wherein, R1 and R2 may be the same or different, and are independently selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkoxy groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 aryl groups, substituted or unsubstituted C1-C12 heteroaryl groups, and groups containing the solubilizing group. R3 to R8 may be the same or different, and are independently selected from hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C1 to C10 alkoxy, substituted or unsubstituted C3 to C10 cycloalkyl, substituted or unsubstituted C1 to C10 heterocycloalkyl, substituted or unsubstituted C6 to C12 aryl, substituted or unsubstituted C1 to C12 heteroaryl, and groups containing the solubilizing group. Any two of n1, n2, m1, and m2 may be the same or different, and are independently selected from 0, 1, and 2, respectively, and the sum of n1 and m1 is 2, the sum of n2 and m2 is 2, and at least one of n1 and n2 is not 0.

[0022] When the functional material is a first functional material, at least one of X and R1 to R8 contains the solubilizing group. When the functional material is a second functional material, X is a second coordinating group, and at least one of R1 to R8 contains a solubilizing group. When the functional material is a third functional material, the sum of n1 and n2 is greater than or equal to 2, X is an initiating group, and at least one of R1 to R8 contains a solubilizing group.

[0023] In some embodiments, the functional material is selected from any of the structures shown in general formula (II);

[0024]

[0025] Wherein, R9 is selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkene groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 arylene groups, substituted or unsubstituted C1-C12 heteroarylene groups, and groups containing the solubilizing group. p is selected from any one of 0, 1, and 2. q is selected from any one of 1, 2, and 3, and the sum of p and q is 3.

[0026] When the functional material is a first functional material, at least one of X and R9 contains a solubilizing group. When the functional material is a second functional material, X is a second coordinating group, and R9 contains a solubilizing group. When the functional material is a third functional material, q is greater than or equal to 2, X is an initiating group, and at least one of the R9 connected to X contains a solubilizing group.

[0027] In some embodiments, the solubilizing group includes an ester group and / or an ether group.

[0028] On the other hand, a light-emitting device is provided. The light-emitting device includes an anode, a cathode, and a light-emitting layer. The anode and cathode are disposed opposite to each other. The light-emitting layer is located between the anode and the cathode. The material of the light-emitting layer includes a cross-linked quantum dot material formed from the quantum dot material of the above embodiments.

[0029] The beneficial effects that the aforementioned light-emitting devices can achieve are the same as those that the aforementioned quantum dot materials can achieve, and will not be repeated here.

[0030] In some embodiments, the light-emitting device is disposed on a substrate. The cathode is closer to the substrate than the anode.

[0031] In some embodiments, the light-emitting device further includes an electron transport layer. The electron transport layer is located between the cathode and the light-emitting layer and is in contact with the light-emitting layer.

[0032] In another aspect, a method for fabricating a light-emitting device is provided. The method includes forming a cathode, an anode, and a light-emitting layer. The cathode and anode are disposed opposite to each other. The light-emitting layer is located between the anode and the cathode. The material of the light-emitting layer includes a cross-linked quantum dot material formed from quantum dot materials. The quantum dot material includes a quantum dot bulk and a functional material. The functional material contains aromatic amine groups and solubilizing groups. The solubilizing groups are used to increase the solubility of the functional material in a predetermined solvent, and the ratio between the mass of the functional material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45.

[0033] The beneficial effects that can be achieved by the above-mentioned method for preparing the light-emitting device are the same as those that can be achieved by the above-mentioned light-emitting device, and will not be repeated here.

[0034] In some embodiments, the light-emitting device is formed on a substrate. Forming the light-emitting layer includes: spin-coating a material of the initial light-emitting layer onto the side of the cathode away from the substrate to form the initial light-emitting layer. The material of the initial light-emitting layer includes a quantum dot material and a predetermined solvent. Target areas of the initial light-emitting layer are exposed, causing the material in the exposed portion of the initial light-emitting layer to transform into cross-linked quantum dot material. The initial light-emitting layer is then developed using a developer solution. The developer solution includes a predetermined solvent.

[0035] In some embodiments, the material forming the initial luminescent layer includes: mixing a quantum dot bulk, an initial ligand material, and a preset solvent to form a quantum dot stock solution. The ratio between the mass of the initial ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.13. The initial ligand material includes a first ligand material. The first ligand material is configurable in the quantum dot bulk. The first ligand material contains a first photosensitive group. Alternatively, the initial ligand material includes a second functional material. The second functional material is configurable in the quantum dot bulk. The second functional material contains a second photosensitive group. The functional material includes a second functional material. Alternatively, the initial ligand material includes a first ligand material and a second functional material. The first ligand material and the second functional material are configurable in the quantum dot bulk. The first ligand material contains a first photosensitive group. The functional material includes a second functional material.

[0036] In some embodiments, the material forming the initial luminescent layer further includes a first supplementary ligand material added to the quantum dot stock solution. The ratio between the mass of the first supplementary ligand material and the mass of the quantum dot bulk is in the range of 0 to 0.35. If the initial ligand material includes the first ligand material, the first supplementary ligand material includes the first ligand material. If the initial ligand material includes a second functional material, the first supplementary ligand material includes the second functional material.

[0037] In some embodiments, the material of the initial light-emitting layer and / or the developing solution further includes a first functional material. The functional material includes the first functional material. The first functional material is not connected to the quantum dot body.

[0038] In some embodiments, the material of the initial light-emitting layer further includes a third functional material. The functional material includes a third functional material. The third functional material contains at least two initiating groups. When the quantum dot material includes a first ligand material, the initiating groups are configured to react with a first photosensitive group under illumination to form a cross-linked quantum dot material; when the quantum dot material includes a second functional material, and the second functional material contains a second photosensitive group, the initiating groups are configured to react with the second photosensitive group under illumination to form a cross-linked quantum dot material.

[0039] In some embodiments, the developing solution further includes a second supplementary ligand material. The ratio between the mass of the second supplementary ligand material in the developing solution and the mass of the quantum dot bulk in the initial luminescent layer ranges from 0 to 0.1. If the initial ligand material includes a first ligand material, the second supplementary ligand material includes the first ligand material. If the initial ligand material includes a second functional material, the second supplementary ligand material includes the second functional material. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0041] Figure 1 This is a structural diagram of a display panel according to some embodiments;

[0042] Figure 2A This is a structural diagram of a display panel according to some other embodiments;

[0043] Figure 2B This is a structural diagram of a display panel according to some other embodiments;

[0044] Figure 3 This is a diagram illustrating the steps of forming a light-emitting layer according to some embodiments;

[0045] Figure 4 This is a diagram illustrating the steps of forming the light-emitting layer according to some other embodiments;

[0046] Figure 5 This is a diagram illustrating the steps of forming the light-emitting layer according to some other embodiments;

[0047] Figure 6This is a schematic diagram of cross-linking of quantum dot materials according to some embodiments;

[0048] Figure 7 This is a structural diagram of a light-emitting device according to some embodiments;

[0049] Figure 8 This is a flowchart illustrating the fabrication process of a light-emitting device according to some embodiments;

[0050] Figure 9 This is a diagram illustrating the fabrication steps of the light-emitting layer according to some embodiments;

[0051] Figure 10 Thermogravimetric analysis diagram of quantum dot stock solution according to some embodiments;

[0052] Figure 11 This is a structural diagram of a light-emitting device according to some other embodiments;

[0053] Figure 12 The image shows the photoluminescence effect of quantum dot materials according to some embodiments;

[0054] Figure 13 A scanning electron microscope (SEM) image of quantum dot material after development according to some embodiments;

[0055] Figure 14 This is a diagram illustrating the photoluminescence effect of a quantum dot material according to some other embodiments. Detailed Implementation

[0056] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0057] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0058] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0059] In describing some embodiments, the terms "coupled" and "connected," and their derivative expressions, may be used. The term "connected" should be interpreted broadly; for example, a "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium. The term "coupled," for example, indicates that two or more components have direct physical or electrical contact. The term "coupled" or "communicatively coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0060] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0061] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0062] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0063] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0064] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0065] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0066] like Figure 1 As shown, some embodiments of this disclosure provide a display panel 200, which includes a plurality of light-emitting devices 100 and a plurality of pixel driving circuits 231.

[0067] The aforementioned display panel 200 can be applied to a display device. The display device can be any display device that displays either moving (e.g., video) or stationary (e.g., still images), and whether it displays text or images. More specifically, the display panel of the described embodiment is contemplated for implementation in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0068] In some embodiments, such as Figure 1 As shown, the display panel 200 includes a substrate 210 and a light-emitting functional layer 220 disposed on one side of the substrate 210. The light-emitting functional layer 220 includes a plurality of light-emitting devices 100. That is, the plurality of light-emitting devices 100 can be disposed on one side of the substrate 210.

[0069] For example, a plurality of light-emitting devices 100 may be arranged along a second direction Y, which is, for example, a direction parallel to the plane where the substrate 210 is located.

[0070] For example, the material of the substrate 210 can be a rigid material, such as glass, to realize a rigid substrate display; or the material of the substrate 210 can also be a flexible material, such as polyimide (PI) or polyethylene terephthalate (PET), to realize a flexible substrate display.

[0071] In some examples, such as Figure 1 As shown, the display panel 200 also includes a driving circuit layer 230 disposed between the substrate 210 and the light-emitting functional layer 220, and the driving circuit layer 230 includes a plurality of pixel driving circuits 231.

[0072] For example, in the display panel 200, the pixel driving circuit 231 can generate a driving current. Each light-emitting device 100 can emit light under the driving action of the driving current generated by the corresponding pixel driving circuit 231. The light emitted by multiple light-emitting devices 100 cooperates with each other, thereby enabling the display panel 200 to achieve the display function.

[0073] In some examples, the driving circuit layer 230 includes crisscrossing strips of cathodes and anodes, with the intersecting portions emitting light. In this case, the pixel driving circuit 231 does not employ TFT technology, and the display panel 200 can be referred to as a passive driving display panel (e.g., a passive driving QLED display panel, PMQLED display panel).

[0074] In other examples, the driving circuit layer 230 includes multiple pixel driving circuits 231 arranged in an array, each pixel driving circuit 231 comprising multiple transistor TFTs. The pixel driving circuits 231 are electrically connected to the light-emitting device 100 and are used to drive the light-emitting device 100 to emit light. In this case, the pixel driving circuits 231 employ TFT technology, and the display panel 200 can be referred to as an active-drive display panel (e.g., an active-drive QLED display panel, an AMQLED display panel). Among these, AMQLED display panels have received increasing attention due to their potential advantages in wide color gamut and long lifespan, and their quantum efficiency is continuously improving, essentially reaching the level of industrialization.

[0075] In some examples, such as Figure 1 As shown, the display panel 200 also includes an encapsulation layer 240, which may be disposed on the side of the plurality of light-emitting devices 100 away from the substrate 210. It should be understood that the encapsulation layer 240 can cover the light-emitting devices 100 to prevent moisture and oxygen from the external environment from entering the display panel 200, damaging the materials in the light-emitting devices 100 and shortening the lifespan of the display panel 200.

[0076] For example, the driving circuit layer 230, the light-emitting functional layer 220 and the encapsulation layer 240 can be stacked on the substrate 210, and the driving circuit layer 230, the light-emitting functional layer 220 and the encapsulation layer 240 are arranged sequentially in a direction away from the substrate 210.

[0077] In some embodiments, such as Figure 1 As shown, in the display panel 200, the light-emitting functional layer 220 also includes a pixel defining layer 221, which has multiple openings Q, and multiple light-emitting devices 100 can be set one-to-one with the multiple openings Q.

[0078] The aforementioned display panel 200 can be, for example, a QLED display panel, in which case the light-emitting device 100 is a QLED light-emitting device. Based on the quantum confinement effect, quantum dots (QDs) possess excellent light-emitting properties such as broadband absorption, narrowband emission, and continuously tunable peak positions. Simultaneously, quantum dots are solution-processable, thus avoiding the use of expensive vacuum equipment. This allows quantum dot light-emitting diodes (QLEDs) using quantum dots as the light-emitting material to serve as a new type of light-emitting diode (LED), possessing advantages such as high color purity, high luminous quantum efficiency, tunable emission wavelength, and high photoluminescence quantum yield. They are considered strong contenders for next-generation display and solid-state lighting technologies and are widely used in display lighting, solar cells, and photoelectric detection, for example, in new wide-color-gamut, high-resolution display devices (electroluminescent or photoluminescent).

[0079] In some embodiments, such as Figure 7 As shown, the light-emitting device 100 includes an anode 15, a cathode 11, and a light-emitting layer 13. The anode 15 and the cathode 11 are disposed opposite to each other. The light-emitting layer 13 is located between the anode 15 and the cathode 11.

[0080] For example, such as Figure 7 As shown, the anode 15, the light-emitting layer 13, and the cathode 11 can be stacked along the first direction X, which intersects with the second direction Y. For example, the second direction Y is perpendicular to the first direction X.

[0081] Based on the above structure, the light-emitting principle of the light-emitting device 100 is as follows: the circuit connected by the anode 15 and the cathode 11 (e.g., pixel driving circuit 231, such as...) Figure 1 Holes are injected into the light-emitting layer 13 using the anode 15, and electrons are injected into the light-emitting layer 13 using the cathode 11. The injected electrons and holes form excitons (i.e., electron-hole pairs) in the light-emitting layer 13. The excitons return to the ground state through radiative transition and emit photons.

[0082] For example, to ensure that the light-emitting device 100 can emit light effectively, the anode 15 can be made of a material with a high work function. This allows holes in the anode 15 to migrate effectively to the light-emitting layer 13 under the drive of the electric field, thereby recombineing with electrons from the cathode 11 to emit light. The material of the anode 15 can be a transparent conductive metal oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, the anode 15 can be a composite electrode containing multiple materials, such as ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO, or GO / IZO, where Ag is silver, CNT is carbon nanotube, and GO is graphene oxide.

[0083] In some examples, the cathode 11 can be made of a material with a low work function, which makes it easier for electrons in the cathode 11 to be injected into the electron transport unit 12. This allows electrons in the cathode 11 to migrate effectively to the light-emitting layer 13 under the drive of the electric field, thereby recombineing with holes in the anode 15 to emit light. The cathode 11 can be made of metals, metal oxides, or metal alloys, such as aluminum (Al), silver (Ag), gold (Au), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium (Li), potassium (K), sodium (Na), tin (Sn), titanium (Ti), lead (Pb), samarium (Sm), yttrium (Y), indium tin oxide (ITO), magnesium-silver alloy (Mg:Ag), ytterbium-gold alloy (Yb:Au), and ytterbium-silver alloy. The cathode 11 can be made of materials such as (Yb:Ag), lithium aluminum alloy (Li:Al), or lithium calcium magnesium alloy (Li:Ca:Al); or, the cathode 11 can be made of a multilayer material, such as magnesium / aluminum (Mg / Al), magnesium / silver (Mg / Ag), aluminum / silver (Al / Ag), aluminum / gold (Al / Au), ytterbium / gold (Yb / Au), ytterbium / silver (Yb / Ag), calcium / magnesium (Ca / Mg), calcium / silver (Ca / Ag), barium / silver (Ba / Ag), etc.

[0084] In some embodiments, such as Figure 7 As shown, to improve the luminous efficiency of the light-emitting device 100, the light-emitting device 100 further includes a hole transport unit 14, located on the side of the light-emitting layer 13 near the anode 15 and in contact with the light-emitting layer 13. The hole transport unit 14 includes, for example, at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL) stacked together.

[0085] In some embodiments, such as Figure 7 As shown, to improve the luminous efficiency of the light-emitting device 100, the light-emitting device 100 further includes an electron transport unit 12, located on the side of the light-emitting layer 13 near the cathode 11 and in contact with the light-emitting layer 13. The electron transport unit 12 includes, for example, at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (EBL) stacked together.

[0086] By setting up film layers such as hole transport unit 14 and electron transport unit 12, it is equivalent to setting transition steps between anode 15 and light-emitting layer 13, and between cathode 11 and light-emitting layer 13, reducing the potential barrier height that carrier transitions need to overcome, and making the luminous efficiency higher.

[0087] For example, the material of the hole transport layer can be poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)](TFB).

[0088] For example, the material of the hole injection layer can be poly(3,4-ethylenedioxythiophene) (PEDOT).

[0089] In some embodiments, such as Figure 7 As shown, in order to improve the luminous efficiency of the light-emitting device 100, the light-emitting device 100 includes an electron transport layer.

[0090] For example, the material of the electron transport layer can be zinc oxide or zinc magnesium oxide.

[0091] In the fabrication method of QLED light-emitting devices, the light-emitting layer 13 (see...) Figure 7 The patterning process is a key step in realizing high-resolution full-color QLED displays. It can be achieved through photolithography, which is the process of patterning quantum dots by exposure and development. It includes two methods: indirect photolithography and direct photolithography.

[0092] Indirect photolithography requires the use of photoresist and sometimes a sacrificial layer to assist in the stripping process. However, it presents some problems in practical applications: on the one hand, the harsh development conditions can damage the already formed light-emitting layer, affecting the efficiency of the light-emitting device; on the other hand, when fabricating QLED display panels that can achieve full-color display, the photoresist (and the sacrificial layer) are repeatedly applied, making the entire process complex and unfavorable for industrial production.

[0093] In contrast, the principle of direct photolithography is as follows: Photosensitive ligands are attached to the surface of the quantum dot matrix. Utilizing the characteristic that the solubility of these ligands in solvents is strongly affected by light (e.g., decomposition, cross-linking, or desorption), a development process is used to pattern the target area of ​​the light-emitting layer. For example, based on the photosensitive properties of these ligands, photochemical reactions occur between ligands or between ligands and cross-linking materials during exposure, altering the solubility of the quantum dot material in the solvent and forming cross-linked quantum dot materials with lower solubility. Development then removes the quantum dot material in unexposed, non-target areas, allowing the target area to form a specific pattern for the light-emitting layer of a QLED device. In other words, quantum dot materials can exhibit a negative photolithography effect; after exposure, the quantum dot material becomes insoluble in the developer due to cross-linking, thus preventing it from being washed away and remaining after development, achieving the goal of patterning the light-emitting layer. When the light-emitting layer is formed by direct photolithography, the damage to the film quality during the fabrication of the light-emitting device can be minimized, and the patterning process can be simplified.

[0094] Based on the above direct photolithography process, in some embodiments, the material of the light-emitting layer 13 includes cross-linked quantum dot material formed from quantum dot material.

[0095] For example, the quantum dot material includes a quantum dot luminescent material and a cross-linking material; wherein the quantum dot luminescent material includes a quantum dot matrix and a ligand material disposed on the quantum dot matrix. The cross-linking material can be configured to undergo a cross-linking reaction with the ligand material under light radiation conditions to generate a cross-linked quantum dot material. With the above configuration, the luminescent layer of a QLED light-emitting device can be formed by photolithography.

[0096] In some implementations, the electron mobility and hole mobility in the light-emitting layer of QLED devices are relatively unbalanced, leading to reduced device efficiency. One possible reason is that when the light-emitting layer is formed using photolithography, some cross-linked material molecules may have relatively poor carrier transport properties, and segments of these cross-linking agents may remain in the cross-linked quantum dot material, potentially hindering carrier transport in the light-emitting layer. Another possible reason is the difference in carrier transport properties between different film layers, which may cause an imbalance in carrier mobility within the light-emitting layer.

[0097] Therefore, in some embodiments, materials with good carrier transport properties are added to the quantum dot light-emitting layer to balance the electron mobility and hole mobility of the quantum dot light-emitting layer material, thereby improving the efficiency and lifetime of QLED light-emitting devices. For example, hole injection in the quantum dot light-emitting layer is usually more difficult than electron injection. Therefore, compounds with strong electron-donating ability can be added to the quantum dot light-emitting layer, because these compounds generally have high hole mobility, which can improve the exciton recombination characteristics of the quantum dot light-emitting layer, thus balancing the electron mobility and hole mobility in the quantum dot light-emitting layer. For example, a small molecule hole transport material, 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCTA), a carbazole derivative, can be added to the quantum dot emitting layer. The nitrogen atoms on TCTA have strong electron-donating ability, enhanced π-π interaction, good conjugation, and high hole mobility, which can help increase the number of holes in the emitting layer, improve the exciton recombination characteristics of the emitting layer, and balance the electron and hole mobility in the quantum dot emitting layer. When the amount of TCTA added is 10% by weight, it can effectively adjust the energy level structure of the hole transport layer and the quantum dot emitting layer, so that the holes and electrons injected into the emitting layer reach a balance, thereby improving the device efficiency.

[0098] In some implementations, the added materials with good carrier transport properties have low solubility in the solution (which can be understood as a quantum dot solution) due to their inherent structural limitations. Moreover, these materials with good carrier transport properties are difficult to form a uniform system when added to the quantum dot solution, making it difficult for them to participate in film formation and affecting the role of balancing electron mobility and hole mobility in the light-emitting layer.

[0099] In some implementations, when the light-emitting layer of a QLED light-emitting device is fabricated using direct photolithography, the quantum dot material and the material of the adjacent functional layer (hereinafter referred to as the front film layer) are affected by intermolecular interactions during the development process. This causes some quantum dot material to remain in non-target areas after development, resulting in multiple colors of light-emitting material within a single sub-pixel area. This causes color crosstalk and color mixing problems, such as red / green / blue mixing, ultimately leading to a reduction in the color gamut and photoelectric performance of the QLED display panel. For example, when the front film layer is an electron transport layer, the electron transport layer material (e.g., zinc oxide / zinc magnesium oxide) may anchor some of the quantum dot material, resulting in poor development performance.

[0100] Based on this, some embodiments of this disclosure provide a quantum dot material. For example... Figures 3-5 and Figure 7 As shown, the quantum dot material comprises: the quantum dot bulk and a functional material. The functional material contains aromatic amine groups and solubilizing groups. The solubilizing groups are used to increase the solubility of the functional material in a preset solvent. The ratio between the mass of the functional material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45.

[0101] For example, the preset solvent can be a solvent for quantum dot solutions.

[0102] In some examples, the quantum dot body may include any one or more of the following: group II-VI quantum dots, group III-V quantum dots, group IV-VI quantum dots, group IV quantum dots, group I-III-VI quantum dots, group I-II-IV-VI quantum dots, core-shell quantum dots, and ABX3 type perovskite quantum dots, or any combination thereof.

[0103] Among them, the II-VI group quantum dots can be selected from one or more of the following binary compounds: CdS, CdSe, CdTe, ZnS, ZnO, ZnSe, ZnTe, HgSe, HgTe and HgS; and one or more of the following ternary compounds: HgxCd1-xTe, HgxCd1-xS, HgxCd1-xSe, HgxZn1-xTe, CdxZn1-xSe, CdxZn1-xS and ZnTeSe, wherein 0 < x < 1, but not limited thereto.

[0104] Group III-V quantum dots can be selected from: InP, InAs, InSb, GaAs, GaP, GaN, GaSb, GaNk, InN, AlP, AlN, AlAs, InGaAs, InGaN, or mixtures thereof; but are not limited thereto.

[0105] Group IV-VI quantum dots can be selected from: PbS, PbSe, PbTe, or mixtures thereof; but are not limited to these.

[0106] A core-shell quantum dot is a quantum dot in which one material forms the core and the other forms the shell. For example, a CdS@ZnS quantum dot means that the core material is CdS and the shell material is ZnS. Core-shell quantum dots can be selected from one or more of the following: CdS@ZnS, CdSe@CdS, InP@ZnS, CdTe@CdSe, CdSe@ZnTe, CdSe@ZnS, PdS@ZnS, ZnTe@CdSe, ZnSe@CdS, and Cd1-xZnxS@ZnS, where 0 < x < 1, but is not limited to these.

[0107] In ABX3 type perovskite quantum dots, A can be CH3NH3. + (methylamine), NH2CH=NH2 (formamidinium) and Cs + One or more of them, B can be Pb 2+ and Sn 2+ One or two of them, X can be Cl - ,Br - and I -One or more of the following can be used: ABX3 type perovskite quantum dots can include, but are not limited to, CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3 and CsPbI3.

[0108] When multiple quantum dots are combined, the quantum dot bulk material can be an alloy material, such as CsPbCl3 / ZnS or CsPbBr. 3 / One of ZnS, CsPbI3 / ZnS, CdS / ZnSeS / ZnS, CdSe / ZnSeS / ZnS, ZnSe / ZnSeS / ZnS and ZnSeTe / ZnSeS / ZnS.

[0109] In some examples, the aromatic amine group can be an aromatic group containing a nitrogen-containing substituent, in which case the nitrogen element may not be an atom on the ring of the aromatic amine group; for example, the aromatic amine group can be the group corresponding to the aromatic amine derivative after removing one or more atoms (such as H).

[0110] In some other examples, the aromatic amine group can be a nitrogen-containing heteroaromatic group, in which case the nitrogen element can be an atom on the ring of the aromatic amine group; for example, the group corresponding to the removal of one or more atoms (such as H) from a carbazole derivative, or the group corresponding to the removal of one or more atoms (such as H) from a pyrroline derivative.

[0111] For example, the mass of functional materials can be measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) to obtain the ratio between the mass of the functional materials and the mass of the quantum dot bulk.

[0112] For example, the ratio between the mass of the functional material and the mass of the quantum dot bulk can be 0.09, 0.18, 0.27, 0.35, or 0.45, etc.

[0113] Here, there are no limitations on the connection relationship between functional materials and the quantum dot matrix. For example, functional materials may include functional materials that can be coordinately connected to the quantum dot matrix, and / or functional materials that are not connected to the quantum dot matrix.

[0114] With the above configuration, when the light-emitting layer 13 of the QLED light-emitting device is prepared using quantum dot materials, firstly, by including aromatic amine groups in the functional materials, the carrier transport performance of the light-emitting layer 13 can be improved. Specifically, the nitrogen atoms in the aromatic amine groups have strong electron-donating ability, strong π-π interaction, and good conjugation, resulting in high hole mobility of the functional materials. Secondly, the solubilizing groups of the functional materials can improve the solubility of the functional materials in the preset solvent, allowing the functional materials to exist in the quantum dot solution in a free or bonded form to the quantum dot matrix. This allows the quantum dot matrix and the functional materials to form a uniform and stable quantum dot solution, enabling the functional materials to participate in film formation and facilitating the balancing effect of electron and hole mobility of the functional materials. It also weakens the intermolecular interaction forces between any two of the quantum dot matrix, ligand materials, and front film materials, preventing quantum dot materials from remaining on the surface of the front film after development, thus solving the problem of color crosstalk. Here, the ligand materials are, for example, the first ligand material and / or the second functional material described in detail below.

[0115] Furthermore, when the ratio between the mass of the functional material and the mass of the quantum dot body is large (e.g., greater than 0.45), it will result in a greater amount of functional material surrounding the quantum dot body in the quantum dot material of the light-emitting layer 13. This may cause discontinuous light emission of the light-emitting layer 13 and hinder the light emission performance of the quantum dot body. Therefore, by setting the ratio between the mass of the functional material and the mass of the quantum dot body to be greater than 0 and less than or equal to 0.45, the electron mobility and hole mobility in the light-emitting layer 13 can be balanced while ensuring the continuity of light emission of the light-emitting layer 13, thereby improving the light emission efficiency of the light-emitting device 100.

[0116] In some embodiments, the preset solvent comprises ether groups and / or ester groups.

[0117] In some examples, the preset solvent can be a solvent in the quantum dot solution, and / or a developer in the photolithography process.

[0118] For example, the preset solvent may be propylene glycol methyl ether acetate (PGMEA). It should be understood that PGMEA is a non-polluting solvent, thus reducing the environmental impact of using the preset solvent. Furthermore, when PGMEA is used as a developer, it has a positive effect on the light-emitting layer 13 and the carrier transport functional layer (e.g., ...). Figure 7 The destructive effect of the film layer in the hole transport unit 14 and / or electron transport unit 12 shown is small, and it can be achieved with virtually no damage.

[0119] It is understandable that by presetting the solvent to contain ether groups and / or ester groups, the solubility of quantum dot materials in quantum dot solutions can be improved, thereby increasing the concentration of quantum dot materials in the quantum dot solution and, to some extent, improving the formation of the luminescent layer 13 (see [reference]). Figure 7 The content of quantum dots in the matrix increases the luminescence efficiency; moreover, solvents containing ether groups and / or ester groups generally have lower toxicity and lower volatility, which can reduce the environmental impact of the pre-selected solvent.

[0120] In some embodiments, the solubilizing group includes an ester group.

[0121] Understandably, ester groups have strong polarity and can form strong interactions with molecules in a pre-set solvent (e.g., PGMEA), thereby increasing the solubility of the functional material in the pre-set solvent. This can increase the content of the functional material in the quantum dot solution and improve the effectiveness of the functional material in preventing the quantum dot bulk from remaining on the surface of the pre-film layer.

[0122] In some embodiments, the solubilizing group includes an ether group.

[0123] Understandably, ether groups have good compatibility with organic solvents and can form strong interactions with pre-set solvents (e.g., PGMEA). Similarly, as mentioned above, this can increase the content of functional materials in quantum dot solutions.

[0124] For example, the functional groups (e.g., ester groups and / or ether groups) contained in functional materials can be qualitatively or quantitatively measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR).

[0125] In some embodiments, such as Figure 3 As shown, the functional material includes a first functional material. The first functional material contains a first aromatic amine group and a solubilizing group. The first functional material is not connected to the quantum dot bulk.

[0126] Here, there is no limitation on the number of solubilizing groups contained in the first functional material. For example, as shown in formulas (a) and (d) described below, the first functional material may include one solubilizing group; and as shown in formulas (a1), (s), and (g) described below, the first functional material may include two solubilizing groups.

[0127] It should be understood that when the first functional material is not connected to the quantum dot matrix, the first functional material and the quantum dot matrix are not connected by chemical bonds or coordination bonds. In other words, the first functional material can be distributed freely around the quantum dot matrix.

[0128] Understandably, firstly, the solubilizing group can increase the solubility of the first functional material in the preset solvent, enabling the first functional material and the quantum dot matrix to form a uniform and stable system. Secondly, when the first functional material is distributed freely around the quantum dot matrix, it can form a physical barrier effect. This can increase the distance between the quantum dot matrix and the front film material, weakening the anchoring effect of the front film layer (e.g., electron transport layer) on the quantum dot matrix. It can also increase the distance between the quantum dot matrices. In other words, the first functional material can act as a dispersant for the quantum dot matrix, inhibiting the aggregation of the quantum dot matrix. This reduces the adsorption between the quantum dot matrix and the front film material, preventing the quantum dot matrix from remaining on the surface of the front film layer, thus improving the development effect.

[0129] In some embodiments, the ratio between the mass of the first functional material and the mass of the quantum dot bulk is in the range of 0 to 0.35.

[0130] For example, the ratio between the mass of the first functional material and the mass of the quantum dot bulk can be 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, or 0.35, etc. It should be understood that the ratio between the mass of the first functional material and the mass of the quantum dot bulk can be 0, that is, the quantum dot material may not contain the first functional material.

[0131] Understandably, when the mass ratio of the first functional material to the mass of the quantum dot body is large (e.g., greater than 0.35), the spacing between the quantum dot bodies may be too large, affecting the light emission continuity of the light-emitting layer. Therefore, by setting the mass ratio of the first functional material to the mass of the quantum dot body to be in the range of 0 to 0.35, the amount of the first functional material in the quantum dot material can be kept within a suitable range, which can prevent the quantum dot material from remaining on the surface of the front film layer while ensuring the light emission continuity of the light-emitting layer.

[0132] As mentioned above, quantum dot materials may also include ligand materials coordinated to the quantum dot bulk, the ligand materials being configured at least to prevent the quantum dot bulk from agglomerating in order to stabilize the quantum dot solution. The following will exemplarily describe the types and amounts of ligand materials in quantum dot materials.

[0133] In some embodiments, such as Figure 4 As shown, the functional material includes a second functional material. The second functional material comprises a second aromatic amine group, a second coordinating group, and a solubilizing group. The second functional material can be located within the quantum dot matrix.

[0134] Here, there is no limit to the number of second coordinating groups contained in the second functional material.

[0135] For example, as shown in formula (b1) described below, the second functional material may include a second coordinating group.

[0136] Here, the second functional material can be liganded into the quantum dot matrix. This means that the surface atoms or groups of the quantum dot matrix can interact with the ligand groups in the second functional material through shared electrons or electron transfer between atoms or molecules, forming coordinate bonds. When coordinate bonds are formed, the second functional material can adhere to the surface of the quantum dot matrix. This can prevent the aggregation of quantum dot matrices by forming a barrier effect and / or passivating surface defects of the quantum dot matrix, thereby making the quantum dot matrix more stable.

[0137] Understandably, the solubilizing group can increase the solubility of the second functional material in a pre-defined solvent, enabling the second functional material to form a uniform and stable system with the quantum dot matrix. Furthermore, utilizing the second coordinating group, coordinate bonds can be formed between the second functional material and the quantum dot matrix, allowing at least a portion of the second functional material to attach to the quantum dot matrix, forming a dual-ligand bonded quantum dot system. The portion of the second functional material coordinating with the quantum dot matrix can act as a ligand, passivating surface defects in the quantum dot matrix and reducing its aggregation. The portion of the second functional material not coordinating with the quantum dot matrix can act as a dispersant, existing in a free form around the quantum dot matrix, increasing the spacing between the quantum dot matrix and the pre-film material, as well as between the quantum dot matrices themselves. This prevents quantum dot matrix residues from remaining on the surface of the pre-film layer.

[0138] It should be understood that when a quantum dot material includes a second functional material, the quantum dot material may or may not include a first functional material; there is no limitation here. Furthermore, when a quantum dot material includes both a first and a second functional material, the second aromatic amine group and the first aromatic amine group may be the same or different; there is no limitation here.

[0139] In some embodiments, the second coordinating group is one or more of a hydroxyl group, a phosphate group, and an amino group, or any combination thereof.

[0140] In some embodiments, the second coordinating group includes a carboxyl group and / or a thiol group.

[0141] For example, the carboxyl groups and / or thiol groups contained in the second functional material can be qualitatively or quantitatively measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR).

[0142] Understandably, carboxyl groups and / or thiol groups have strong electrophilicity and can coordinate with the quantum dot matrix to form a relatively stable coordinate bond structure. In this way, the second functional material can be coordinated with the quantum dot matrix.

[0143] In some examples, when the quantum dot material includes a first functional material, the process steps for forming a cross-linked quantum dot material with a light-emitting layer using the quantum dot material are as follows: Figure 3 As shown. When the quantum dot material includes a second functional material, the process steps for forming a cross-linked quantum dot material with a light-emitting layer using the quantum dot material are as follows. Figure 4 As shown. Figure 3 and Figure 4 In this process, during exposure, a mask or mask layer is used to selectively expose the quantum dot material in the target area. The exposed light can include two specific wavelengths λ1 / λ2 (e.g., λ1 = 365 nm, λ2 = 405 nm). During exposure, photosensitive groups undergo a photochemical reaction under illumination, forming cross-linked quantum dot material. The solubility of the cross-linked portion in a preset solvent decreases. Here, the photosensitive groups are photosensitive reactive groups / functional groups, and are configured to at least undergo a cross-linking reaction under illumination.

[0144] The following examples illustrate the forms in which photosensitive groups exist in quantum dot materials.

[0145] In some embodiments, the second functional material further comprises a second photosensitive group.

[0146] For an understanding of the second photosensitive group, please refer to the foregoing exemplary description of the photosensitive group, which will not be repeated here.

[0147] Understandably, when the second functional material contains a second photosensitive group, the second functional material has photosensitivity and can act as a photosensitive ligand for the quantum dot matrix. In this way, the second functional material connected to one quantum dot matrix and the second functional material connected to another quantum dot matrix can directly undergo a cross-linking reaction under light, or indirectly undergo a cross-linking reaction through the cross-linking material, to form a stable three-dimensional network structure and form a cross-linked quantum dot material. This cross-linked quantum dot material will remain in the target area after development to achieve the purpose of patterning the target area.

[0148] It should be understood that when a quantum dot material includes a second functional material, and the second functional material contains a second photosensitive group, the ligand material of the quantum dot body may only include the second functional material.

[0149] In some examples, the ligand material of the quantum dot body also includes other ligand materials besides the secondary functional material.

[0150] In some embodiments, the quantum dot material further includes a first ligand material. The first ligand material comprises a first photosensitive group. The first ligand material may be ligated into the quantum dot body.

[0151] It should be understood that when the first ligand material is coordinable to the quantum dot body, the first ligand material contains a coordinating group that can coordinate with the quantum dot body, such as one or more of a carboxyl group, a hydroxyl group, a phosphate group, and an amino group, or any combination thereof.

[0152] For an understanding of the first photosensitive group, please refer to the foregoing exemplary description of the photosensitive group, which will not be repeated here.

[0153] For example, the first ligand material can be one or more of mono[2-[(2-methylacryloyl)oxy]ethyl] succinate (MMES) and 4-(2-(acryloyloxy)ethoxy)-4-oxobutyric acid. The MMES molecule contains carbon-carbon double bonds, ester groups, and carboxyl groups, and can serve as an X-type ligand for the quantum dot matrix. The carboxyl groups on the MMES and the metal cations on the quantum dot each provide an electron to form a coordinate bond, which facilitates the coordination of the MMES with the quantum dot matrix.

[0154] It should be understood that when a quantum dot material includes a first ligand material, the quantum dot material may or may not include a first functional material; moreover, the quantum dot material may or may not include a second functional material, and no limitation is set here.

[0155] Understandably, by including a first ligand material in the quantum dot material, on the one hand, the first ligand material can coordinate with the quantum dot body through coordination bonds, which can increase the spacing between the quantum dot bodies and ensure that the quantum dot bodies have good dispersion; on the other hand, by including a first photosensitive group in the first ligand material, the quantum dot material can undergo a cross-linking reaction under light irradiation, so that the quantum dot material can form cross-linked quantum dot materials to achieve the purpose of selective patterning.

[0156] In some examples, the quantum dot material includes a quantum dot body and a first ligand material. In this case, under light irradiation, the first photosensitive group contained in the first ligand material can undergo a self-crosslinking reaction, or a crosslinking reaction with a crosslinking material. The first ligand material can ensure the crosslinking effect of the quantum dot material.

[0157] In some other examples, the quantum dot material includes a quantum dot body, a first ligand material, and a second functional material. The second functional material does not contain a photosensitive group. In this case, under illumination, the first photosensitive group contained in the first ligand material can undergo a self-crosslinking reaction or a crosslinking reaction with a crosslinking material. The first ligand material can ensure the crosslinking effect of the quantum dot material.

[0158] In some other examples, the quantum dot material comprises a quantum dot matrix, a first ligand material, and a second functional material, the second functional material further comprising a second photosensitive group. In this case, under illumination, self-crosslinking reactions can occur between the first photosensitive groups, between the second photosensitive groups, and between the first and second photosensitive groups; alternatively, crosslinking reactions can occur between the first photosensitive group and the crosslinking material, and between the second photosensitive group and the crosslinking material. The first ligand material and the second functional material ensure the crosslinking effect of the quantum dot material.

[0159] In some embodiments, where the second functional material contains a second photosensitive group, the second photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups, and azide groups.

[0160] In some embodiments, where the quantum dot material includes a first ligand material, the first photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups, and azide groups.

[0161] It should be understood that the alkenyl group contains an unsaturated carbon-carbon double bond, and the alkynyl group contains an unsaturated carbon-carbon triple bond. When the first photosensitive group and / or the second photosensitive group contains an alkenyl group or an alkynyl group, under light irradiation conditions, self-crosslinking reactions (e.g., addition reactions) can occur between alkenyl groups, between alkynyl groups, or between alkenyl groups and alkynyl groups. Alternatively, crosslinking reactions can occur between alkenyl groups and crosslinking materials or between alkynyl groups and crosslinking materials, causing the quantum dot material to form a crosslinked quantum dot material.

[0162] For example, when the first photosensitive group and / or the second photosensitive group contains an alkenyl group, in the quantum dot material, the alkenyl group attached to one quantum dot matrix can undergo an addition reaction with the alkenyl group attached to another quantum dot matrix, thereby connecting one quantum dot matrix to another, thus forming a cross-linked quantum dot material. As another example, when the first photosensitive group and / or the second photosensitive group contains an alkenyl group, the alkenyl group attached to one quantum dot matrix can undergo an addition reaction with the first part of the cross-linked material; the alkenyl group attached to another quantum dot matrix can undergo an addition reaction with the second part of the cross-linked material, thereby connecting one quantum dot matrix to another through the cross-linked material, thus forming a cross-linked quantum dot material.

[0163] It should be understood that the benzophenone group can be photolyzed under light conditions (hv) to generate a triplet ketone intermediate, the structure of which is shown in the following formula. The C in the triplet ketone intermediate... ● -O ● It will attack the nearby CH bonds to cause a cross-linking reaction, causing the quantum dot material to form a cross-linked quantum dot material.

[0164]

[0165] For example, when the first and / or second photosensitive groups contain benzophenone groups, in the quantum dot material, the benzophenone groups attached to one quantum dot matrix can undergo a hydrocarbon insertion reaction with a ligand material (e.g., a second functional material and / or a first ligand material) attached to another quantum dot matrix, thereby connecting one quantum dot matrix to another, thus forming a cross-linked quantum dot material. As another example, when the first and / or second photosensitive groups contain benzophenone groups, the benzophenone groups attached to one quantum dot matrix can undergo a hydrocarbon insertion reaction with the first portion of the cross-linked material; the benzophenone groups attached to another quantum dot matrix can undergo a hydrocarbon insertion reaction with the second portion of the cross-linked material, thereby connecting one quantum dot matrix to another through the cross-linked material, thus forming a cross-linked quantum dot material.

[0166] It should be understood that the azide group can be photolyzed under light conditions to generate the reactive intermediate free radical nitrogen carbene. Nitrogen carbene attacks nearby CH bonds to induce a cross-linking reaction, causing the quantum dot material to form a cross-linked quantum dot material.

[0167] For example, when the first and / or second photosensitive groups contain azide groups, the azide groups attached to one quantum dot matrix can undergo a hydrocarbon insertion reaction with a ligand material (e.g., a second functional material and / or a first ligand material) attached to another quantum dot matrix, thus connecting one quantum dot matrix to another, thereby forming a cross-linked quantum dot material. As another example, when the first and / or second photosensitive groups contain azide groups, the azide groups attached to one quantum dot matrix can undergo a hydrocarbon insertion reaction with the first portion of the cross-linked material; the azide groups attached to the other quantum dot matrix can undergo a hydrocarbon insertion reaction with the second portion of the cross-linked material, thus connecting one quantum dot matrix to another through the cross-linked material, thereby forming a cross-linked quantum dot material.

[0168] It should be noted that when the quantum dot material includes a first ligand material and a second functional material, and the second functional material contains a second photosensitive group, the first photosensitive group and the second photosensitive group may be the same or different.

[0169] Understandably, based on the above principles, alkenyl groups, alkynyl groups, benzophenone groups, and azide groups all have photosensitive properties, which can cause quantum dot materials to undergo self-crosslinking reactions, or cause quantum dot materials to undergo crosslinking reactions under the action of crosslinking materials. In this way, quantum dot materials can form crosslinked quantum dot materials, thereby realizing the patterning of the target area of ​​the light-emitting layer.

[0170] In some embodiments, when the quantum dot material includes a first ligand material, the ratio between the mass of the first ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45.

[0171] For example, the mass of the first ligand material can be measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) to obtain the ratio between the mass of the first ligand material and the mass of the quantum dot bulk.

[0172] For example, the ratio between the mass of the first ligand material and the mass of the quantum dot bulk is, for example, 0.05, 0.18, 0.27, 0.36, or 0.45.

[0173] In some embodiments, when the quantum dot material includes a first ligand material and a second functional material, the ratio between the sum of the masses of the first ligand material and the second functional material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.45.

[0174] For example, the mass of the first ligand material and the second functional material can be measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) to obtain the ratio between the sum of the masses of the first ligand material and the second functional material and the mass of the quantum dot bulk.

[0175] For example, the ratio between the sum of the masses of the first ligand material and the second functional material and the mass of the quantum dot bulk is, for example, 0.09, 0.20, 0.27, 0.36, or 0.45.

[0176] Understandably, when the ratio of the mass of the ligand material to the mass of the quantum dot bulk is large (e.g., greater than 0.45), it leads to an excessive amount of ligand material bonded to the quantum dot bulk, resulting in a thick coating layer on the surface of the quantum dot bulk. This hinders the luminescence performance of the quantum dot bulk and also affects the film-forming properties of the luminescent layer, resulting in lower film density. Therefore, by adopting the above-mentioned configuration, the ratio of the total mass of the ligand material (including the first ligand material and / or the second functional material) to the mass of the quantum dot bulk can be kept within a suitable range. This allows for high luminescence performance of the quantum dots and good film-forming properties of the luminescent layer, while also ensuring good dispersibility of the quantum dot material and reducing the aggregation of the quantum dot bulk to prevent quantum dot bulk residues on the surface of the front film layer.

[0177] In some implementations, when QLED light-emitting devices are fabricated using direct photolithography, strong exposure conditions are used, which may damage the material of the light-emitting layer (e.g., quantum dot material).

[0178] In some embodiments, such as Figure 5 and Figure 6 As shown, the functional material includes a third functional material. The third functional material comprises a third aromatic amine group, at least two initiating groups, and a solubilizing group. When the quantum dot material includes a first ligand material, the initiating group is configured to react with a first photosensitive group under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material. When the quantum dot material includes a second functional material, and the second functional material includes a second photosensitive group, the initiating group is configured to react with the second photosensitive group under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material. The solubility of the cross-linked quantum dot material in a predetermined solvent is less than the solubility of the quantum dot material in the predetermined solvent.

[0179] It should be understood that when the initiating group is configured to react with the first photosensitive group and / or the second photosensitive group under light to form a cross-linked quantum dot material, the third functional material can be reused as the cross-linked material described in the foregoing section. Here, the cross-linked material can also be understood as an initiator.

[0180] In some examples, the ligand material of the quantum dot material is the first ligand material. In this case, the initiating group of the third functional material can react with the first photosensitive group under light irradiation, so that the quantum dot material forms a cross-linked quantum dot material.

[0181] In some other examples, the ligand material of the quantum dot material is a second functional material containing a second photosensitive group. In this case, the initiating group of the third functional material can react with the second photosensitive group under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material.

[0182] In some other examples, the ligand material of the quantum dot material is a first ligand material and a second functional material containing a second photosensitive group. In this case, the initiating group of the third functional material can react with the first photosensitive group and / or the second photosensitive group under light irradiation, so that the quantum dot material forms a cross-linked quantum dot material.

[0183] Understandably, firstly, the solubilizing group can increase the solubility of the third functional material in a preset solvent, enabling the third functional material to form a uniform and stable system with the quantum dot matrix. Secondly, when the third functional material is reused as a cross-linking material, the initiating group can react with the first and / or second photosensitive groups under light irradiation, causing the quantum dot material to form a cross-linked quantum dot material. This cross-linked quantum dot material has a denser cross-linked network structure, which is beneficial for improving the film retention effect after the development process. Thirdly, when the third functional material is reused as a cross-linking material, the exposure dose in the photolithography process can be reduced to some extent, weakening the impact of strong exposure conditions on the emissive layer material and preventing damage to the emissive layer material from strong exposure conditions.

[0184] It should be understood that when a quantum dot material includes a third functional material, the quantum dot material may include a first functional material and / or a second functional material, or may include a first functional material and / or a second functional material; there is no limitation here.

[0185] It should be noted that when the quantum dot material includes a first functional material and a third functional material, the first aromatic amine group and the third aromatic amine group may be the same or different. When the quantum dot material includes a second functional material and a third functional material, the second aromatic amine group and the third aromatic amine group may be the same or different; no restrictions are set here.

[0186] In some embodiments, the initiating group includes a thiol group.

[0187] For example, the thiol groups contained in the third functional material can be qualitatively or quantitatively measured by methods such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR).

[0188] It should be noted that when a functional material contains two thiol groups, it can be either a second or third functional material. In this case, the type of functional material can be determined based on its role in the quantum dot material. For example, if a functional material contains two thiol groups and can undergo cross-linking reactions with the first ligand material and / or the second functional material, it can be a third functional material. Conversely, if a functional material contains two thiol groups and cannot undergo cross-linking reactions with the first ligand material and / or other second functional materials, it can be a second functional material.

[0189] Understandably, when the initiating group includes a thiol group, the thiol group can undergo a cross-linking reaction with the first photosensitive group and / or the second photosensitive group under light irradiation. For example, when the first photosensitive group and / or the second photosensitive group are alkenyl groups, the thiol group can undergo a cross-linking reaction with the unsaturated bonds on the alkenyl group under light irradiation. In this way, multiple quantum dot bodies can be bridged to form a cross-linked quantum dot material with a dense cross-linked network structure, which is beneficial to improving the film retention effect after the development process and reducing the impact of strong exposure conditions on the material of the light-emitting layer.

[0190] In some embodiments, the ratio between the mass of the third functional material and the mass of the quantum dot bulk is in the range of 0 to 0.05.

[0191] For example, the ratio between the mass of the third functional material and the mass of the quantum dot bulk may be 0, 0.01, 0.02, 0.03, 0.045, or 0.05, etc. It should be understood that the ratio between the mass of the third functional material and the mass of the quantum dot bulk can be 0, that is, the quantum dot material may not include the third functional material.

[0192] Understandably, by setting the ratio between the mass of the third functional material and the mass of the quantum dot body to be in the range of 0 to 0.05, the mass of the third functional material can be kept within a suitable range, so that the cross-linked quantum dot material formed after cross-linking has a relatively dense cross-linked network structure, thereby improving the film retention effect after the development process and reducing the impact of strong exposure conditions on the material of the light-emitting layer.

[0193] In some embodiments, the functional material is selected from any of the structures shown in the following general formula (I).

[0194]

[0195] R1 and R2 may be the same or different, and are independently selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkoxy groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 arylene groups, substituted or unsubstituted C1-C12 heteroarylene groups, and groups containing solubilizing groups.

[0196] R3 to R8 may be the same or different, and are independently selected from hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C1 to C10 alkoxy, substituted or unsubstituted C3 to C10 cycloalkyl, substituted or unsubstituted C1 to C10 heterocycloalkyl, substituted or unsubstituted C6 to C12 aryl and substituted or unsubstituted C1 to C12 heteroaryl, and groups containing a solubilizing group.

[0197] Any two of n1, n2, m1, and m2 are the same or different, and are independently selected from 0, 1, and 2 respectively. The sum of n1 and m1 is 2, the sum of n2 and m2 is 2, and at least one of n1 and n2 is not 0.

[0198] When the functional material is a first functional material, at least one of X and R1 to R8 contains the solubilizing group. When the functional material is a second functional material, X is a second coordinating group, and at least one of R1 to R8 contains a solubilizing group. When the functional material is a third functional material, the sum of n1 and n2 is greater than or equal to 2, X is an initiating group, and at least one of R1 to R8 contains a solubilizing group.

[0199] In the above general formula (I), an alkylene group of Cx refers to an alkylene group containing a total of x carbon (C) atoms, where x is a positive integer, and the same applies below. For the understanding of other alkylene groups of Cx, such as alkoxide groups, cycloalkylene groups, heteroalkylene groups, etc., please refer to the above content, and they will not be repeated here.

[0200] When R1 and R2 are selected from any one of substituted C1-C10 alkylene, substituted C1-C10 alkoxy, substituted C3-C10 cycloalkylene, substituted C1-C10 heterocyclic alkylene, substituted C6-C12 aryl or substituted C1-C12 heteroaryl, and / or R3-R8 are selected from any one of substituted C1-C10 alkyl, substituted C1-C10 alkoxy, substituted C3-C10 cycloalkyl, substituted C1-C10 heterocyclic alkyl, substituted C6-C12 aryl and substituted C1-C12 heteroaryl, there are no restrictions on the type and number of substituents.

[0201] Understandably, when the functional material is selected from any of the structures shown in general formula (I), and the functional material is a derivative of the aromatic amine derivative N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), it can be similar to TPD, possessing excellent hole transport performance. It can balance electron and hole mobility, effectively regulating the energy level structure of the hole transport layer and the quantum dot emitting layer, thus achieving a balance between holes and electrons injected into the emitting layer. Therefore, by selecting any of the structures shown in general formula (I) for the functional material, the hole transport performance of the quantum dot material can be improved, resulting in a more balanced hole and electron mobility in the emitting layer of the QLED light-emitting device.

[0202] For example, when n1 is 1, m1 is 1, m2 is 2, R1 is methylene, and X is an ester group, the functional material is the first functional material, and its structural formula can be as shown in formula (a).

[0203]

[0204] For example, when n1 is 1, n2 is 1, m1 is 1, m2 is 1, R1 and R2 are methylene groups, and X is an ester group, the functional material is the first functional material, and its structural formula can be as shown in formula (a1) and formula (s).

[0205]

[0206] For example, when n1 is 1, n2 is 1, m1 is 1, m2 is 1, R1 and R2 are methylene groups, and one of the two X groups is a carboxyl group and the other is an ester group, the functional material is a second functional material, and its structural formula can be as shown in formula (b1).

[0207]

[0208] For example, when n1 is 1, m1 is 1, m2 is 2, and R1 is R y And R y It contains an ester group, X is a thiol group, and the functional material is a second functional material. Its structural formula can be shown as shown in formula (c).

[0209]

[0210] For example, when n1 is 1, n2 is 1, m1 is 1, m2 is 1, and R1 and R2 are R y And R y When it contains an ester group and X is a thiol group, the functional material is a third functional material, and its structural formula can be as shown in formula (c1).

[0211]

[0212] It should be noted that the structural formulas listed above are examples of the structures of functional materials, not restrictions on functional materials. Moreover, (a) and others in the above structural formulas are alternative names for each structural formula, not part of the structural formula itself, where x takes a positive integer.

[0213] The following examples illustrate the synthesis process of a functional material with the structure shown in general formula (I). Examples include a first functional material with the structure shown in formula (a) and a second functional material with the structure shown in formula (c). It should be understood that the synthesis processes of other first functional materials (excluding the first functional material with the structure shown in formula (a)) and other second functional materials (excluding the second functional material with the structure shown in formula (c)) can be obtained by controlling reaction conditions (e.g., reactants, solvent, feed ratio, reaction temperature, etc.), and will not be exhaustively described here.

[0214] In some examples, firstly, intermediate M1 is synthesized using TPD and N-bromosuccinimide; the structural formulas of TPD, N-bromosuccinimide, and intermediate M1, as well as the chemical reaction formula for the synthesis of intermediate M1, are shown below.

[0215]

[0216] For example, the reaction of synthesizing intermediate M1 using TPD and N-bromosuccinimide is a Wol-Ziegler bromination reaction. The specific process includes: dissolving TPD and N-bromosuccinimide in chloroform at a molar ratio of 1:2, heating to 50°C to 70°C, reacting at this temperature for 6 to 24 hours, and then purifying and filtering to obtain intermediate product M1.

[0217] It should be noted that the bromination reaction site in the above reaction is not limited to the methyl group. In practical applications, other bromine-substituted products besides intermediate M1 can be obtained by changing the reactants and reaction conditions. For example, by adding an appropriate amount of glacial acetic acid, a bromination reaction on the benzene ring can be induced to obtain a tetrabromine-substituted product as shown in the following formula. In this case, by appropriately adjusting the conditions described below for synthesizing intermediate M2 using intermediate M1, synthesizing the first functional material using intermediate M2, synthesizing the second functional material using the first functional material, and synthesizing the second functional material using intermediate M2, the first and second functional materials based on the tetrabromine-substituted product can be obtained. For example, the first functional material with the structure shown in (s) can be obtained.

[0218]

[0219] Then, intermediate M2 is synthesized using intermediate M1 and pyridine. The structural formulas of intermediate M1, pyridine, and intermediate M2, as well as the chemical reaction formula for the synthesis of intermediate M2, are shown below.

[0220]

[0221] For example, the reaction of synthesizing intermediate M2 using intermediate M1 and pyridine is an aromatic amination reaction. The specific process includes: dissolving intermediate M1 in DMSO, adding pyridine in a 1 molar ratio, heating to 60°C, and reacting at this temperature for 6 to 24 hours, followed by purification and filtration to obtain intermediate product M2. In this process, pyridine can replace an equimolar amount of bromine.

[0222] Then, a first functional material with the structure shown in formula (a) is synthesized using intermediate M2 and ethyl mercaptoester. The structural formulas of intermediate M2, ethyl mercaptoester, and the first functional material, as well as the chemical reaction formula for synthesizing the first functional material with the structure shown in formula (a) are shown below.

[0223]

[0224] For example, the reaction of synthesizing the first functional material with the structure shown in formula (a) using intermediate M2 and ethyl mercaptoside is a nucleophilic substitution reaction. The specific process includes: dissolving an appropriate amount of NaH or K2CO3 in DMF to obtain a mixture, then dissolving intermediate M2 in the mixture, adding ethyl mercaptoside at a molar ratio of 1.5, heating to 60°C, and reacting at this temperature for 6 to 24 hours to obtain the first functional material with the structure shown in formula (a).

[0225] It should be noted that in the above reaction, ethyl mercaptoacetate can be replaced with other long-chain compounds with similar structures.

[0226] In some examples, intermediate M2 is used in conjunction with dithiol molecules (SH-R) y -SH, R y Containing ester groups, it can react to obtain a second functional material with the structure shown in formula (c). The structural formulas of intermediate M2, dithiol molecules and the second functional material, as well as the chemical reaction formula for the synthesis of the second functional material with the structure shown in formula (c) are shown below.

[0227]

[0228] The above is an exemplary description of a method for preparing a functional material with a structure as shown in general formula (II). Another general formula structure of functional materials will be exemplarily introduced below.

[0229] In some embodiments, the functional material is selected from any of the structures shown in the following general formula (II).

[0230]

[0231] R9 is selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkoxy groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 arylene groups, substituted or unsubstituted C1-C12 heteroarylene groups, and groups containing a solubilizing group.

[0232] p is selected from 0, 1, and 2.

[0233] q is selected from any one of 1, 2 and 3, and the sum of p and q is 3.

[0234] When the functional material is a first functional material, at least one of X and R9 contains a solubilizing group. When the functional material is a second functional material, X is a second coordinating group, and R9 contains a solubilizing group. When the functional material is a third functional material, q is greater than or equal to 2, X is an initiating group, and at least one of the R9 connected to X contains a solubilizing group.

[0235] For an understanding of Cx, please refer to the previous text; it will not be repeated here.

[0236] When R9 is selected from any of the following: substituted C1-C10 alkylene, substituted C1-C10 alkoxy, substituted C3-C10 cycloalkylene, substituted C1-C10 heteroalkylene, substituted C6-C12 aryl, and substituted C1-C12 heteroaryl, there are no restrictions on the type and number of substituents.

[0237] Understandably, when the functional material is selected from any of the structures shown in general formula (II), the functional material is a derivative of the carbazole derivative 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCTA), which, similar to TCTA, exhibits excellent hole transport performance. Specifically, the structure shown in general formula (II) contains three carbazole units bonded to nitrogen atoms. These carbazole units are electron-rich, possess a stable conjugated system, and have a high electron cloud density, resulting in strong hole transport performance. Therefore, by selecting any of the structures shown in general formula (II) for the functional material, the hole transport performance of quantum dot materials can be improved, leading to a more balanced hole mobility and electron mobility in the emitting layer of QLED light-emitting devices.

[0238] For example, when q is 1 or 2, R9 is methylene, and X is an ester group, the functional material is the first functional material, and its structural formula can be as shown below.

[0239]

[0240] For example, when q is 1 and X is a thiol group, the functional material is a second functional material, and its structural formula can be as shown below.

[0241]

[0242] For example, p is 1, q is 2, R9 is methylene, and when X is a thiol group, the functional material is a third functional material, and its structural formula can be as shown in formula (k).

[0243]

[0244] It should be noted that the structural formulas listed above are examples of the structures of functional materials, not restrictions on functional materials. Furthermore, (k) and other terms in the above structural formulas are approximations of each structural formula, not part of the structural formula itself, where x takes a positive integer value.

[0245] The following examples illustrate the synthesis process of a functional material with the structure shown in general formula (II), using a first functional material with the structure shown in formula (d) and a second functional material with the structure shown in formula (f) as examples. It should be understood that the synthesis processes of other first functional materials besides the first functional material with the structure shown in formula (d) and other second functional materials besides the second functional material with the structure shown in formula (f) can be obtained by controlling reaction conditions (e.g., reactants, solvent, feed ratio, reaction temperature, etc.), and will not be exhaustively described here.

[0246] In some examples, intermediate M3 is first synthesized using TCTA and p-fluorobenzoyl chloride; the structural formulas of TCTA, p-fluorobenzoyl chloride, and intermediate M3, as well as the chemical reaction formula for the synthesis of intermediate M3, are shown below.

[0247]

[0248] For example, the reaction of synthesizing intermediate M3 using TCTA and p-fluorobenzoyl chloride is a Friedel-Crafts acylation reaction. The specific process includes: dissolving a strong Lewis acid (e.g., anhydrous AlCl3 or FeCl3), TCTA and p-fluorobenzoyl chloride in dichloromethane under ice bath conditions, then slowly raising the temperature to room temperature and reacting at room temperature for 3 to 12 hours, followed by cooling in an ice bath, purification and filtration to obtain intermediate M3.

[0249] It should be noted that the number of reaction sites in the above reaction is not limited to one. For example, the number of reaction sites in the Friedel-Crafts acylation reaction can be two to obtain intermediate M5 as shown in the following formula. In this case, by appropriately adjusting the conditions for synthesizing the first functional material using the intermediate, synthesizing the second functional material using the first functional material, and synthesizing the second functional material using the intermediate as described below, the first functional material and the second functional material based on intermediate M5 can be obtained. For example, the first functional material with the structure shown in (g) and the third functional material with the structure shown in (k) can be obtained.

[0250]

[0251] It should be noted that the reaction for synthesizing intermediates using TCTA is not limited to Friedel-Crafts acylation; other reactions are also possible. For example, the reaction for synthesizing intermediates using TCTA can be the Wol-Ziegler bromination reaction, in which case the reaction formula for synthesizing intermediate M4 can be shown below.

[0252]

[0253] Then, a first functional material with the structure shown in formula (d) is synthesized using intermediate M3 and ethyl mercaptohydrate. The structural formulas of intermediate M3, ethyl mercaptohydrate, and the first functional material, as well as the chemical reaction formula of the first functional material with the structure shown in formula (d), are shown below.

[0254]

[0255] For example, the reaction of synthesizing the first functional material with the structure shown in formula (d) using intermediate M3 and ethyl mercaptoester is a nucleophilic substitution reaction. The specific process includes: mixing an appropriate amount of NaH or K2CO3 with DMF to obtain a mixture, then adding intermediate M3 to the mixture and adding ethyl mercaptoester at a molar ratio of 1.5, heating to 60°C, and reacting at 60°C for 6 h to 24 h to obtain the first functional material with the structure shown in formula (d).

[0256] It should be noted that in the above reaction, ethyl mercaptoacetate can be replaced with other long-chain compounds with similar structures.

[0257] In some examples, intermediate M3 can be reacted with dithiol molecules (SH-Ry-SH, where Ry contains an ester group) to obtain a second functional material with the structure shown in formula (f). The structural formulas of intermediate M3, dithiol molecules and the second functional material, as well as the chemical reaction formula for the synthesis of the second functional material with the structure shown in formula (f) are shown below.

[0258]

[0259] The above is an exemplary description of quantum dot materials. The structure of the light-emitting device 100 will be described exemplary below.

[0260] In some examples, such as Figure 1 and Figure 7 As shown, based on the direction of light emission, the light-emitting device 100 can be classified into top-emitting light-emitting device, bottom-emitting light-emitting device, and double-sided emitting light-emitting device.

[0261] In the bottom-emitting light-emitting device, the light emitted by the light-emitting layer 13 is emitted from the substrate 210 side. At this time, the anode 15 and the cathode 11, which are relatively closer to the substrate 210, can be a light-transmitting electrode (such as a transparent electrode or a semi-transparent electrode), and the one that is relatively farther away from the substrate 210 can be an opaque electrode; for example, an opaque reflective electrode.

[0262] In a top-emitting light-emitting device, the light emitted by the light-emitting layer 13 is emitted from the side away from the substrate 210. Since the light needs to be emitted from the side away from the substrate 210, the one of the anode 15 and the cathode 11 that is relatively closer to the substrate 210 can be an opaque electrode, such as an opaque reflective electrode, while the one that is relatively farther away from the substrate 210 can be a transparent electrode or a semi-transparent electrode.

[0263] Understandably, in a bottom-emitting light-emitting device, light passes through the substrate 210, causing it to be blocked by the pixel driving circuit 231 on the substrate 210. Therefore, compared to a bottom-emitting light-emitting device, a top-emitting light-emitting device has a relatively higher aperture ratio in the pixel defining layer 221 and a relatively higher light transmittance.

[0264] The double-sided emitting light-emitting device 100 allows light emitted from its light-emitting layer to exit from both the side away from the substrate 210 and the side of the substrate 210, enabling the display panel to have a double-sided display function. Since the light needs to be emitted in two directions, both the anode 15 and the cathode 11 must be configured as light-transmitting electrodes.

[0265] In some examples, the light-emitting device 100 can be classified as a positive light-emitting device and an inverted light-emitting device, depending on the type of electrode that contacts the substrate (e.g., including substrate 210 and driving circuit layer 230).

[0266] like Figure 2A As shown, when the electrode in contact with the substrate is the anode 15, the light-emitting device 100 is a positive light-emitting device. The anode 15 in contact with the substrate can realize the function of hole generation and injection. The structure of the positive light-emitting device includes, for example, an anode 15, a hole transport unit 14, a light-emitting layer 13, an electron transport unit 12, and a cathode 15 arranged sequentially in a direction away from the substrate 210.

[0267] like Figure 2B As shown, when the electrode in contact with the substrate is the cathode 11, the light-emitting device 100 is an inverted light-emitting device. The cathode 11 in contact with the substrate can realize the function of generating and injecting electrons. The structure of the inverted light-emitting device includes, for example, a cathode 11, an electron transport unit 12, a light-emitting layer 13, a hole transport unit 14, and an anode 15 arranged sequentially in a direction away from the substrate 210.

[0268] The hole transport unit 14 includes, for example, a hole injection layer and a hole transport layer. The electron transport unit 12 includes, for example, an electron transport layer and an electron injection layer. For exemplary descriptions of the cathode 11, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, and anode 15, please refer to the foregoing sections, and they will not be repeated here.

[0269] It should be noted that, Figure 2A and Figure 2B This is a schematic diagram of the display panel 200 with the driving circuit layer 230 omitted.

[0270] In some embodiments, such as Figure 2B As shown, the light-emitting device 100 is disposed on the substrate 210. The cathode 11 is closer to the substrate 210 than the anode 15.

[0271] Understandably, by setting it up this way, the light-emitting device 100 is an inverted light-emitting device. On the one hand, the material of the thin-film transistor substrate 210 is mainly n-type semiconductor material, and the structure of the inverted light-emitting device can effectively match this characteristic, which can simplify the process and improve the display resolution. On the other hand, when preparing the inverted light-emitting device, other film layers after the light-emitting layer 13 (e.g., hole transport layer and hole injection layer) can be prepared by vapor deposition, which can achieve uniform film layer control and improve the film layer uniformity of the light-emitting device 100.

[0272] In some examples, the light-emitting device 100 is an inverted top-emitting light-emitting device, which can be applied to QLED display panels. This facilitates the large-scale application of QLED display technology.

[0273] On another front, some embodiments of this disclosure provide a method for fabricating a light-emitting device 100, such as... Figure 7 and Figure 8 As shown, it includes S1.

[0274] S1: Forming a cathode 11, an anode 15, and a light-emitting layer 13. The cathode 11 and anode 15 are positioned opposite each other. The light-emitting layer 13 is located between the anode 11 and the cathode 15. The material of the light-emitting layer 13 includes cross-linked quantum dot material formed from quantum dot material. The quantum dot material includes a quantum dot matrix and a functional material. The functional material contains aromatic amine groups and solubilizing groups. The solubilizing groups are used to increase the solubility of the functional material in a preset solvent. The ratio between the mass of the functional material and the mass of the quantum dot matrix is ​​greater than 0 and less than or equal to 0.45.

[0275] The beneficial effects achievable by the above-mentioned method for preparing light-emitting devices are the same as those achievable by the above-mentioned quantum dot materials, and will not be repeated here.

[0276] In some embodiments, a cathode 11, an anode 15, and a light-emitting layer 13 are formed, including S1.1 to S1.3.

[0277] S1.1: Forming cathode 11.

[0278] For an understanding of the cathode 11, please refer to the foregoing exemplary description of the cathode 11, which will not be repeated here.

[0279] S1.2: Forming the light-emitting layer 13.

[0280] For an understanding of the light-emitting layer 13, please refer to the foregoing exemplary description of the light-emitting layer 13, which will not be repeated here.

[0281] S1.3: Forms anode 15.

[0282] For an understanding of anode 15, please refer to the foregoing exemplary description of anode 15, which will not be repeated here.

[0283] Understandably, when the formation of cathode 11, anode 15 and light-emitting layer 13 includes S1.1 to S1.3, the light-emitting device is an inverted light-emitting device. As mentioned above, this can simplify the process flow and improve the display resolution; moreover, it can achieve uniform film layer control, thereby improving the film layer uniformity of the light-emitting device 100.

[0284] In some examples, S1.1A is included after S1.1 and before S1.2.

[0285] S1.1A: Form an electron transport unit 12, which includes, for example, at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (EBL).

[0286] For an understanding of the electronic transmission unit 12, please refer to the foregoing exemplary description of the electronic transmission unit 12, which will not be repeated here.

[0287] For example, the electron transport unit 12 includes an electron transport layer, and the electron transport layer is prepared by the sol-gel method. Of course, other methods can also be used to prepare the electron transport layer.

[0288] For example, the electron transport unit 12 includes an electron transport layer, and the material of the electron transport layer is zinc oxide / magnesium zinc oxide. In this case, the preparation method of the electron transport layer may include an annealing process. By setting it this way, firstly, the electrical properties of the electron transport layer itself can be improved, and secondly, the damage to the light-emitting layer 13 and other functional films caused by heat treatment can be effectively reduced.

[0289] In some examples, S1.3A is included after S1.2 and before S1.3.

[0290] S1.3A: Forming a hole transport unit 14, which includes, for example, at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0291] For an understanding of the hole transmission unit 14, please refer to the foregoing exemplary description of the hole transmission unit 14, which will not be repeated here.

[0292] In some embodiments, the light-emitting device 100 is formed on the substrate 210, such as Figure 9 As shown, the light-emitting layer 13 includes S1.2.1 to S1.2.3.

[0293] S1.2.1: At the cathode 11, away from the substrate 210 (see...) Figure 1 The material of the initial light-emitting layer 13a is spin-coated onto one side of the light-emitting layer to form the initial light-emitting layer 13a. The material of the initial light-emitting layer 13a includes quantum dot material and a preset solvent.

[0294] For example, the material of the initial light-emitting layer 13a is spin-coated on the side of the electron transport unit 12 (e.g., electron transport layer) away from the cathode 11 to form the initial light-emitting layer 13a.

[0295] S1.2.2: Expose the target area of ​​the initial luminescent layer 13a, so that the exposed part of the material in the initial luminescent layer 13a is transformed into cross-linked quantum dot material.

[0296] For example, exposing the target area of ​​the initial luminescent layer 13a may include: exposing it with light of a first wavelength or full-spectrum light. Alternatively, exposing it with light of a second wavelength followed by exposing it with light of the first wavelength. Or, exposing it with light of the first wavelength followed by exposing it with light of the second wavelength. Here, the first wavelength is, for example, ultraviolet light with a wavelength of 365 nm, and the second wavelength is, for example, ultraviolet light with a wavelength of 405 nm.

[0297] For example, in S1.2.2, a mask template or mask layer is used to expose the target area of ​​the initial light-emitting layer 13a.

[0298] S1.2.3: The initial luminescent layer 13a is developed using a developer solution. The developer solution includes a pre-set solvent.

[0299] It should be understood that after development, the quantum dot material in the unexposed area is removed, while the cross-linked quantum dot material in the exposed area is retained, thereby achieving the patterning of the light-emitting layer 13.

[0300] Understandably, when the formation of the light-emitting layer 13 includes S1.2.1 to S1.2.3, the process for preparing the light-emitting layer 13 is a direct photolithography process. Compared with the indirect photolithography process, the light-emitting device preparation process can have less destructive effect on the film quality and can simplify the patterning process.

[0301] In some embodiments, such as Figure 9 As shown, the material forming the initial luminescent layer 13a includes: a quantum dot stock solution formed by mixing the quantum dot bulk, the initial ligand material, and a preset solvent. The ratio between the mass of the initial ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.13.

[0302] In some examples, the initial ligand material includes a first ligand material. The first ligand material can be ligated to the quantum dot bulk. The first ligand material contains a first photosensitive group.

[0303] In other examples, the initial ligand material includes a second functional material. The second functional material can be ligated into the quantum dot bulk. The second functional material contains a second photosensitive group. In this case, the functional material includes the second functional material.

[0304] In other examples, the initial ligand material comprises a first ligand material and a second functional material. The first ligand material and the second functional material are collimated within the quantum dot bulk. The first ligand material contains a first photosensitive group. In this case, the functional material comprises a second functional material.

[0305] For example, the ratio between the mass of the initial ligand material and the mass of the quantum dot bulk can be 0.01, 0.03, 0.05, 0.07, 0.08, 0.10, or 0.13, etc.

[0306] Understandably, when the ratio between the mass of the initial ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.13, it can improve the dispersion of the quantum dot bulk in the quantum dot stock solution and facilitate the long-term storage of the quantum dot stock solution.

[0307] In some examples, quantum dot stock solutions with MMES as the initial ligand material were prepared using a ligand exchange process. Before the ligand exchange, the ligand material ligated to the quantum dot matrix was oleic acid; after the exchange, MMES was ligated to the quantum dot matrix. These quantum dot stock solutions were then subjected to thermogravimetric analysis (TGA), and the measured structures are shown below. Figure 10 As shown in the figure. The weight loss percentage for sample A is 11.04%, for sample B it is 10.46%, and for sample C it is 10.03%. Figure 10 It can be seen that the ratio between the mass of the initial ligand material in the quantum dot stock solution and the mass of the quantum dot body and the initial ligand material can be stably controlled at around 10.5%, and the ligand exchange process has high repeatability.

[0308] In some embodiments, such as Figure 9 As shown, the material forming the initial luminescent layer 13a further includes a first supplementary ligand material added to the quantum dot stock solution. The ratio between the mass of the first supplementary ligand material and the mass of the quantum dot bulk is in the range of 0 to 0.35. When the initial ligand material includes the first ligand material, the first supplementary ligand material includes the first ligand material. When the initial ligand material includes a second functional material, the first supplementary ligand material includes the second functional material.

[0309] For example, the ratio between the mass of the first supplementary ligand material and the mass of the quantum dot bulk can be 0, 0.02, 0.05, 0.08, 0.10, 0.15, 0.20, 0.25, or 0.35, etc. It should be understood that the ratio between the mass of the first supplementary ligand material and the mass of the quantum dot bulk can be 0, that is, the quantum dot stock solution may not contain the first supplementary ligand material.

[0310] Understandably, when quantum dots aggregate, they are more likely to remain on the surface of the pre-film layer. Adding a first supplementary ligand to the quantum dot stock solution serves several purposes: first, it acts as a dispersant, reducing quantum dot aggregation; second, it allows the supplementary ligand to directly coordinate with the quantum dot mass, passivating surface defects and further reducing aggregation; and third, it enables a dynamic ligand exchange reaction between the supplementary ligand and the initial ligand, displacing the quantum dots originally adsorbed on the pre-film layer back into the developing solution and removing them during subsequent development processes. This prevents quantum dot material from remaining on the surface of the pre-film layer after development.

[0311] Furthermore, when the ratio of the mass of the first supplementary ligand material to the mass of the quantum dot matrix is ​​greater than 0.35, it may result in a larger amount of ligand material ligated to the quantum dot matrix, hindering the luminescence performance of the quantum dot matrix and increasing the isolation between the quantum dot and its surrounding environment, thus affecting the film-forming performance of the luminescent layer 13. Therefore, by setting the ratio of the mass of the first supplementary ligand material to the mass of the quantum dot matrix to be within the range of 0 to 0.35, the ratio can be kept within a suitable range. This ensures both the luminescence performance of the quantum dot matrix and the film-forming performance of the luminescent layer 13, while preventing quantum dot material residue on the surface of the pre-film layer after development.

[0312] Furthermore, when the first supplementary ligand material includes both the first ligand material and the second functional material, the electrical performance of the light-emitting device can be controlled by adjusting their ratio, thereby maintaining the electrical performance to a greater extent.

[0313] In some embodiments, such as Figure 9 As shown, the material of the initial luminescent layer 13a also includes a first functional material. The first functional material is not connected to the quantum dot bulk. In this case, the functional material includes the first functional material.

[0314] In some embodiments, such as Figure 9 As shown, the developing solution also includes a first functional material. The first functional material is not connected to the quantum dot bulk. In this case, the functional material includes the first functional material.

[0315] For a description of the first functional material, please refer to the foregoing exemplary description of the first functional material, which will not be repeated here.

[0316] Understandably, when the material of the initial luminescent layer 13a and / or the developing solution includes the first functional material, the first functional material can act as a dispersant to reduce the aggregation of quantum dot materials. Moreover, the first functional material can play a physical barrier role between the quantum dot body and the front film layer (such as the electron transport layer) material, and between the ligand material and the lower functional layer material, weakening the anchoring effect of the front film layer material on the quantum dots. In this way, the residue of quantum dot materials on the surface of the front film layer can be prevented, thereby solving the problem of color crosstalk.

[0317] In some embodiments, the material of the initial light-emitting layer 13a further includes a third functional material. The functional material includes a third functional material. The third functional material contains at least two initiating groups. In this case, the functional material includes a third functional material. When the quantum dot material includes a first ligand material, the initiating group is configured to react with a first photosensitive group under illumination to form a cross-linked quantum dot material; when the quantum dot material includes a second functional material, and the second functional material contains a second photosensitive group, the initiating group is configured to react with the second photosensitive group under illumination to form a cross-linked quantum dot material.

[0318] For a description of the third functional material, please refer to the foregoing exemplary description of the third functional material, which will not be repeated here.

[0319] Understandably, through the above configuration, the third functional material can act as a crosslinking material, reacting with the first and / or second photosensitive groups under illumination to form crosslinked quantum dot materials. These crosslinked quantum dot materials possess a denser crosslinked network structure, which is beneficial for improving film retention after the development process. Furthermore, when the third functional material can act as a crosslinking material, it can reduce the exposure dose in the photolithography process to some extent, mitigating the impact of strong exposure conditions on the emissive layer material and preventing damage to the emissive layer material from strong exposure conditions.

[0320] In some embodiments, such as Figure 9 As shown, the developing solution also includes a second supplementary ligand material. The ratio between the mass of the second supplementary ligand material in the developing solution and the mass of the quantum dot bulk in the material of the initial luminescent layer 13a ranges from 0 to 0.1. When the initial ligand material includes the first ligand material, the second supplementary ligand material includes the first ligand material. When the initial ligand material includes the second functional material, the second supplementary ligand material includes the second functional material.

[0321] For example, the ratio between the mass of the second supplementary ligand material in the developing solution and the mass of the quantum dot bulk in the material of the initial luminescent layer 13a can be 0, 0.01, 0.03, 0.05, 0.06, 0.08, or 0.1. It should be understood that the ratio between the mass of the second supplementary ligand material in the developing solution and the mass of the quantum dot bulk in the material of the initial luminescent layer 13a can be 0, meaning that the developing solution may not contain the second supplementary ligand material.

[0322] Understandably, with the above settings, the second supplementary ligand material in the developer is the same as the initial ligand material in the initial luminescent layer. This allows the second supplementary ligand material to undergo a ligand exchange reaction with the initial ligand material, displacing the quantum dot matrix located in the unexposed area and originally adsorbed on the front film layer back into the developer. This reduces the residue of quantum dot material on the surface of the front film layer, prevents color crosstalk, and improves the color gamut of the display panel. Furthermore, when the ratio of the mass of the second supplementary ligand material to the mass of the quantum dot matrix in the initial luminescent layer 13a is large (e.g., greater than 0.1), it may reduce the fluidity and solubility of the developer, resulting in poor development. Therefore, by setting the ratio of the mass of the second supplementary ligand material in the developer to the mass of the quantum dot matrix in the initial luminescent layer 13a to a range of 0 to 0.1, the residue of quantum dot material on the surface of the front film layer can be reduced while ensuring the development effect of the developer.

[0323] Moreover, when the second supplementary ligand material includes the first ligand material and the second functional material, the electrical performance of the light-emitting device can be regulated by adjusting the ratio of the two, thereby maintaining the electrical performance to a greater extent.

[0324] In order to objectively evaluate the technical effects of the embodiments of this disclosure, the technical solutions provided by this disclosure will be described in detail and by way of example through the following experimental examples and comparative examples.

[0325]

Example 1

[0326] The following embodiments demonstrate the fabrication of a display panel 200, wherein the structure of the light-emitting device 100 included in the display panel 200 is as follows: Figure 11 As shown. The preparation method includes R1 to R9.

[0327] R1: Prepare the backplate; the backplate includes a substrate 210 and a patterned cathode layer disposed on the substrate 210, the patterned cathode layer includes a plurality of cathodes 11 (ITO electrodes); the backplate is cleaned sequentially with deionized water and isopropanol, and then dried with a nitrogen gun and baked for later use.

[0328] R2: Preparation of electron transport layer 121, specifically including: adding 1g of zinc acetate dihydrate to a mixed solution of 5mL ethanolamine and dimethoxyethanol, and heating and stirring at 60℃~80℃ for 30min~60min to obtain a zinc oxide precursor solution; after the zinc oxide precursor solution is allowed to stand and cool, an appropriate amount of the zinc oxide precursor solution is dropped onto a backing plate and spin-coated into a film, and then placed on a hot stage at 150℃~300℃ for heat treatment to form a nano zinc oxide film, which is the electron transport layer 121.

[0329] R3: Fabrication of the luminescent layer 13 of the red light-emitting device specifically includes: First, spin-coating the material of the first initial luminescent layer onto the electron transport layer 121. The material of the first initial luminescent layer includes: a red quantum dot matrix, a first ligand material MMES, and a functional material, wherein the functional material exists in a free form or in a form liganded to the quantum dot matrix. Then, using a mask, the target area of ​​the first initial luminescent layer (which can be understood as the area corresponding to the red sub-pixel) is exposed. Subsequently, the first initial luminescent layer is developed using a developing solution to remove the material of the first initial luminescent layer located in the non-target area, while retaining the cross-linked quantum dot material located in the target area, thus obtaining the luminescent layer 13 of the red light-emitting device; the developing solution includes PGMEA, the first ligand material MMES, and the functional material.

[0330] R4: Fabrication of the light-emitting layer 13 of the green light-emitting device specifically includes: First, spin-coating the material of the second initial light-emitting layer onto the electron transport layer 121. The material of the second initial light-emitting layer includes: a green quantum dot matrix, a first ligand material MMES, and a functional material, wherein the functional material exists in a free form or in a form liganded to the quantum dot matrix. Then, using a mask, the target area of ​​the second initial light-emitting layer (which can be understood as the area corresponding to the green sub-pixel) is exposed. Subsequently, the second initial light-emitting layer is developed using a developing solution to remove the material of the second initial light-emitting layer located in the non-target area, while retaining the cross-linked quantum dot material located in the target area, thus obtaining the light-emitting layer of the green light-emitting device; the developing solution includes PGMEA, the first ligand material MMES, and the functional material.

[0331] R5: Fabrication of the luminescent layer 13 of the blue light-emitting device specifically includes: First, spin-coating the material of the third initial luminescent layer onto the electron transport layer 121. The material of the third initial luminescent layer includes: a blue quantum dot matrix, a first ligand material MMES, and a functional material, wherein the functional material exists in a free form or in a form liganded to the quantum dot matrix. Then, using a mask, the target area of ​​the third initial luminescent layer (which can be understood as the area corresponding to the blue sub-pixel) is exposed. Subsequently, the third initial luminescent layer is developed using a developing solution to remove the material of the third initial luminescent layer located in the non-target area, while retaining the cross-linked quantum dot material located in the target area, thus obtaining the luminescent layer of the blue light-emitting device; the developing solution includes PGMEA, the first ligand material MMES, and the functional material.

[0332] R6: Fabrication of hole transport layer 141, specifically including: using spin coating or vapor deposition process to deposit the material (such as TFB) of hole transport layer 141 on the light-emitting layer 13 of red light-emitting device, the light-emitting layer 13 of green light-emitting device, and the light-emitting layer 13 of blue light-emitting device.

[0333] R7: The hole injection layer 142 is prepared by using a spin coating process or a vapor deposition process to deposit the material (such as PEDOT) of the hole injection layer 142 onto the light-emitting layer 13 of the red light-emitting device, the light-emitting layer 13 of the green light-emitting device, and the light-emitting layer 13 of the blue light-emitting device.

[0334] R8: Preparation of anode 15, specifically including: depositing Ag material of anode 15 onto hole injection layer 142 by vapor deposition.

[0335] R9: Package.

[0336]

Example 2

[0337] The following embodiments demonstrate the fabrication of a display panel 200, wherein the structure of the light-emitting device 100 included in the display panel 200 is as follows: Figure 11 As shown. The preparation method includes M1 to M9.

[0338] M1: Prepare the backplate.

[0339] M2: Fabrication of electron transport layer 121.

[0340] M3: Light-emitting layer 13 for preparing red light-emitting devices.

[0341] M4: Light-emitting layer 13 for fabricating green light-emitting devices.

[0342] M5: Light-emitting layer 13 for fabricating blue light-emitting devices.

[0343] M6: Prepare hole transport layer 141.

[0344] M7: Prepare hole injection layer 142.

[0345] M8: Prepare anode 15.

[0346] M9: Package.

[0347] For an understanding of the preparation methods of M1 to M9, please refer to the description of the preparation methods of R1 to R9 in the preceding section, which will not be repeated here.

[0348] In this embodiment, the materials used to form the first initial light-emitting layer 13 for the red light-emitting device, the second initial light-emitting layer 13 for the green light-emitting device, and the third initial light-emitting layer 13 for the blue light-emitting device all include: a quantum dot body, a first ligand material MMES, and functional materials, including a third functional material. The functional materials, excluding the third functional material, exist either in a free form or in a form coordinated to the quantum dot body.

[0349]

Example 3

[0350] In this embodiment, a first quantum dot solution, a second quantum dot solution, a third quantum dot solution, a fourth quantum dot solution, and a fifth quantum dot solution were spin-coated onto an electron transport layer containing zinc oxide / zinc magnesium oxide, respectively. The residual state of the quantum dot material after development was characterized to verify the effect of the ligand material content in the quantum dot solution on the residual state of the quantum dot material.

[0351] The characterization methods for residual conditions include photoluminescence testing and scanning electron microscopy (SEM) observation. The photoluminescence effects of the first, second, third, fourth, and fifth quantum dot solutions are shown in the figures below. Figure 12 (a) Figure 12 (b) Figure 12 (c) Figure 12 (d) and Figure 12 As shown in (e) above. The SEM images of the fourth and fifth quantum dot solutions are shown below. Figure 13 (a) and Figure 13 As shown in (b) of the diagram.

[0352] The first, second, third, fourth, and fifth quantum dot solutions all include the red quantum dot bulk (RQD) and the first ligand material MMES, but the content of the first ligand material MMES varies in each quantum dot solution. Specifically, in the first quantum dot solution (i.e., the quantum dot stock solution), the mass ratio of the first ligand material MMES to the mass of the red quantum dot bulk (RQD) is 11.67%. The second, third, fourth, and fifth quantum dot solutions are obtained by adding the first ligand material MMES to the first quantum dot solution (i.e., the quantum dot stock solution), and the mass ratios of the first ligand material MMES to the mass of the red quantum dot bulk (RQD) in the second, third, fourth, and fifth quantum dot solutions are 20%, 26.25%, 32.5%, and 45%, respectively.

[0353] Depend on Figure 12 As shown in (a), when the spin-coating solution is the first quantum dot solution, the quantum dot material on the surface of the electron transport layer is difficult to remove after development, resulting in severe luminescence of the quantum dot material under photoexcitation; from Figure 12 As shown in (b), when the spin-coating solution is a second quantum dot solution, the development effect is improved, the amount of quantum dot bulk remaining on the electron transport layer surface is reduced, and the photoluminescence intensity is weakened; Figure 12 As shown in (e), when the spin-coating solution is a fifth quantum dot solution, the development effect is significantly improved, and the surface of the electron transport layer is nearly transparent.

[0354] According to statistics, Figure 13 In (a), the number of residual quantum dots after development is approximately 62 per μm. 2 , Figure 13 In (b), the number of residual quantum dots after development is approximately 17 per μm. 2 .

[0355] In summary, by adding ligand materials (such as the first ligand material MMES) to the quantum dot stock solution, the development effect on the zinc oxide / magnesium oxide zinc electron transport layer can be effectively improved.

[0356]

Example 4

[0357] In this embodiment, the second quantum dot solution described in Example 3 was spin-coated onto an electron transport layer containing zinc oxide / zinc magnesium oxide, and then developed using a first developer, a second developer, and a third developer, respectively. The residual quantum dot material after development was characterized to verify the effect of the ligand material content in the developer on the residual quantum dot material. The residual condition was characterized by photoluminescence testing.

[0358] The first, second, and third developing solutions all contain PGMEA and the first ligand material MMES, but the content of the first ligand material MMES in each developing solution is different. Specifically, the mass ratio of the first ligand material MMES in the first developing solution to the mass of the red quantum dot matrix RQD in the second quantum dot solution is 2%; the mass ratio of the first ligand material MMES in the second developing solution to the mass of the red quantum dot matrix RQD in the second quantum dot solution is 5%; and the mass ratio of the first ligand material MMES in the third developing solution to the mass of the red quantum dot matrix RQD in the second quantum dot solution is 10%. The photoluminescence effect diagrams corresponding to the first, second, and third developing solutions are shown below. Figure 14 (a) Figure 14 (b) and Figure 14 As shown in (c) in the figure.

[0359] Depend on Figure 14 It is evident that as the mass of the first ligand material MMES added to the PGMEA developer increases, the problem of quantum dot material residue on the electron transport layer is significantly improved. This may be because the developer with added MMES can undergo a dynamic ligand exchange reaction with the quantum dots in the luminescent film, displacing the quantum dot bulk material originally adsorbed on the electron transport layer in the unexposed area back into the developer.

[0360]

Example 5

[0361] In this embodiment, the sixth quantum dot solution, the seventh quantum dot solution, and the eighth quantum dot solution are spin-coated onto the electron transport layer containing zinc oxide / zinc magnesium oxide, and then developed with a developer.

[0362] The sixth, seventh, and eighth quantum dot solutions all include the red quantum dot matrix (RQD), the first ligand material (MMES), and a functional material, but the types of functional materials differ in each solution. Specifically, the sixth quantum dot solution contains a first functional material, and the solubilizing group is an ester group. Specifically, the first functional material is one or any combination of the first functional materials shown in formulas (a), (a1), (s), (d), and (g). The seventh quantum dot solution contains a second functional material, and the second coordinating group is a carboxyl group. Specifically, the second functional material is the second functional material shown in formula (b1). The eighth quantum dot solution contains a second functional material, and the second coordinating group is a thiol group. Each molecule of the second functional material contains one second coordinating group. Specifically, the second functional material is one or more combinations of the second functional materials shown in formulas (c) and (f).

[0363] Adding excessive amounts of the first ligand material MMES can hinder the overall carrier transport of the light-emitting device. Therefore, this embodiment proposes to synergistically add the first ligand material MMES and functional materials to the quantum dot solution. Adding the first ligand material MMES and functional materials can increase the dispersibility of the quantum dot bulk in the quantum dot solution, weakening the intermolecular interaction forces between quantum dot bulks, between the quantum dot bulk and the front film layer, and between the ligand material and the front film layer in a free or bonded manner, preventing particle aggregation, and thus achieving the purpose of improving the development effect.

[0364] Furthermore, in this embodiment, by appropriately reducing the amount of the first ligand material MMES and increasing the amount of functional material, the effects of preventing quantum dot material residue after development and improving carrier transport performance can be achieved. For example, by reducing the amount of the first ligand material MMES and increasing the amount of the first functional material, the first functional material can be directly used as a dispersant for the quantum dot solution; or, for another example, by reducing the amount of the first ligand material MMES and increasing the amount of the second functional material, the second functional material can undergo a dynamic ligand exchange reaction with the original ligand material connected to the quantum dot body, thereby passivating defects on the surface of the quantum dot body and increasing the dispersibility of the quantum dot body.

[0365]

Example 6

[0366] In this embodiment, a quantum dot solution is spin-coated onto an electron transport layer containing zinc oxide / zinc magnesium oxide, and then developed using a fourth developer, a fifth developer, and a sixth developer, respectively.

[0367] The fourth, fifth, and sixth developing solutions all include PGMEA, the first ligand material MMES, and functional materials, but the types of functional materials differ in each developing solution. Specifically, the functional material included in the fourth developing solution is a first functional material, and the solubilizing group is an ester group. Specifically, the first functional material is one or any combination of the first functional materials shown in formulas (a), (a1), (s), (d), and (g). The functional material included in the fifth developing solution is a second functional material, and the second coordinating group is a carboxyl group. Specifically, the second functional material is the second functional material shown in formula (b1). The functional material included in the sixth developing solution is a second functional material, the second coordinating group is a thiol group, and each molecule of the second functional material contains one second coordinating group. Specifically, the second functional material is one or more combinations of the second functional materials shown in formulas (c) and (f).

[0368] Adding excessive amounts of the first ligand material MMES can hinder the overall carrier transport of the light-emitting device. Therefore, this embodiment proposes to synergistically add the first ligand material MMES and the functional material to the developing solution. Adding the first ligand material MMES and the functional material can increase the dispersibility of the quantum dot bulk in the quantum dot solution, weakening the intermolecular interaction forces between quantum dot bulks, between quantum dot bulks and the front film layer, and between the ligand material and the front film layer in a free or bonded manner, preventing particle aggregation, and thus improving the developing effect.

[0369] Furthermore, in this embodiment, by appropriately reducing the amount of the first ligand material MMES and increasing the amount of functional material, the effects of preventing quantum dot material residue after development and improving carrier transport performance can be achieved. For example, by reducing the amount of the first ligand material MMES and increasing the amount of the first functional material, the first functional material can be directly used as a dispersant in the developer. Alternatively, by reducing the amount of the first ligand material MMES and increasing the amount of the second functional material, the second functional material can undergo a dynamic ligand exchange reaction with the original ligand material connected to the quantum dot matrix, thereby passivating defects on the surface of the quantum dot matrix and increasing the dispersibility of the quantum dot matrix.

[0370]

Example 7

[0371] In this embodiment, a ligand exchange process is used to prepare the quantum dot stock solution. Before the ligand exchange, the ligand material ligated to the quantum dot matrix is ​​the first ligand material MMES. After the ligand exchange, the ligand material ligated to the quantum dot matrix is ​​the first ligand material MMES and the second functional material. The second functional material may have a carboxyl group as a coordinating group; specifically, the second functional material is the second functional material shown in formula (b1). Alternatively, the second coordinating group may be a thiol group, and each molecule of the second functional material contains one thiol group. Specifically, the second functional material is one or more combinations of the second functional materials shown in formulas (c) and (f).

[0372] The molecular structure of the secondary functional material helps to disperse the quantum dot matrix in the quantum dot stock solution. The resulting dual-ligand quantum dot matrix has a certain steric hindrance, which can prevent particle aggregation and thus improve the development effect. Moreover, the secondary functional material contains a second aromatic amine group, which gives it a strong hole transport capability. Therefore, after the secondary functional material is bonded to the surface of the quantum dot matrix, it can help improve the hole injection effect, thereby mitigating the impact of the decrease in hole mobility caused by the photolithography process.

[0373]

Example 8

[0374] In this embodiment, a ninth quantum dot solution is spin-coated onto an electron transport layer containing zinc oxide / zinc magnesium oxide, and then developed with a developer.

[0375] The ninth quantum dot solution comprises a quantum dot bulk, a first ligand material MMES, and a third functional material. Specifically, the third functional material is one or more combinations of the third functional materials shown in formulas (c1) and (k).

[0376] In this embodiment, the third functional material can serve as a crosslinking material in the ninth quantum dot solution. The thiol groups contained in the third functional material can undergo a crosslinking reaction with the unsaturated carbon-carbon double bonds on the first ligand material MMES under ultraviolet light irradiation. In the photolithography process, it can bridge multiple quantum dot bodies to form a denser crosslinking network, enhancing the contrast between exposed and unexposed areas and optimizing the film retention effect after development. Moreover, the improved crosslinking ability can reduce the exposure dose in the photolithography process to a certain extent, weakening the destructive effect of strong exposure conditions on the light-emitting layer. In addition, the third functional material can also improve the problem of reduced mobility caused by the photolithography process.

[0377] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A quantum dot material, characterized in that, include: The quantum dot matrix and the functional material; the functional material contains aromatic amine groups and solubilizing groups, the solubilizing groups being used to increase the solubility of the functional material in a preset solvent, and the ratio between the mass of the functional material and the mass of the quantum dot matrix being greater than 0 and less than or equal to 0.

45.

2. The quantum dot material according to claim 1, characterized in that, The preset solvent contains ether groups and / or ester groups.

3. The quantum dot material according to claim 1, characterized in that, The functional material includes a first functional material, which comprises a first aromatic amine group and the solubilizing group; The first functional material is not connected to the quantum dot body.

4. The quantum dot material according to claim 2, characterized in that, The ratio between the mass of the first functional material and the mass of the quantum dot matrix ranges from 0 to 0.

35.

5. The quantum dot material according to claim 1, characterized in that, The functional material includes a second functional material; the second functional material comprises a second aromatic amine group, a second coordinating group, and the solubilizing group; The second functional material may be disposed within the quantum dot body.

6. The quantum dot material according to claim 5, characterized in that, The second coordinating group includes a carboxyl group and / or a thiol group.

7. The quantum dot material according to claim 5, characterized in that, The second functional material also contains a second photosensitive group.

8. The quantum dot material according to claim 1, characterized in that, It also includes a first ligand material, which contains a first photosensitive group and is ligandable to the quantum dot body.

9. The quantum dot material according to claim 7 or 8, characterized in that, When the second functional material contains a second photosensitive group, the second photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups and azide groups; When the quantum dot material includes a first ligand material, the first photosensitive group includes one or any combination of alkenyl groups, alkynyl groups, benzophenone groups, and azide groups.

10. The quantum dot material according to any one of claims 5 to 8, characterized in that, When the quantum dot material includes a first ligand material, the ratio between the mass of the first ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.

45. When the quantum dot material includes a first ligand material and a second functional material, the ratio between the sum of the masses of the first ligand material and the second functional material and the mass of the quantum dot body is greater than 0 and less than or equal to 0.

45.

11. The quantum dot material according to claim 1, characterized in that, The functional material includes a third functional material, which comprises a third aromatic amine group, at least two initiating groups, and the solubilizing group; In the case where the quantum dot material includes a first ligand material, the initiating group is configured to react with the first photosensitive group under light irradiation, thereby forming a cross-linked quantum dot material. When the quantum dot material includes a second functional material and the second functional material contains a second photosensitive group, the initiating group is configured to react with the second photosensitive group under light irradiation to form a cross-linked quantum dot material. Wherein, the solubility of the cross-linked quantum dot material in the preset solvent is less than the solubility of the quantum dot material in the preset solvent.

12. The quantum dot material according to claim 11, characterized in that, The initiating group includes a thiol group.

13. The quantum dot material according to claim 11 or 12, characterized in that, The ratio between the mass of the third functional material and the mass of the quantum dot body is in the range of 0 to 0.

05.

14. The quantum dot material according to any one of claims 1 to 8 and claim 11, characterized in that, The functional material is selected from any one of the structures shown in the following general formula (I); Wherein, R1 and R2 may be the same or different, and are independently selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkoxy groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 aryl groups, substituted or unsubstituted C1-C12 heteroaryl groups, and groups containing the solubilizing group; R3 to R8 may be the same or different, and are independently selected from hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C1 to C10 alkoxy, substituted or unsubstituted C3 to C10 cycloalkyl, substituted or unsubstituted C1 to C10 heterocycloalkyl, substituted or unsubstituted C6 to C12 aryl and substituted or unsubstituted C1 to C12 heteroaryl, and groups containing the solubilizing group; Any two of n1, n2, m1, and m2 are the same or different, and are independently selected from 0, 1, and 2 respectively. The sum of n1 and m1 is 2, the sum of n2 and m2 is 2, and at least one of n1 and n2 is not 0. When the functional material is a first functional material, at least one of X and R1 to R8 contains the solubilizing group; When the functional material is a second functional material, X is the second coordinating group, and at least one of R1 to R8 contains the solubilizing group; When the functional material is a third functional material, the sum of n1 and n2 is greater than or equal to 2, X is the initiating group, and at least one of R1 to R8 contains the solubilizing group.

15. The quantum dot material according to any one of claims 1 to 8 and claim 11, characterized in that, The functional material is selected from any one of the structures shown in the following general formula (II); Wherein, R9 is selected from any one of the following: substituted or unsubstituted C1-C10 alkylene groups, substituted or unsubstituted C1-C10 alkoxy groups, substituted or unsubstituted C3-C10 cycloalkylene groups, substituted or unsubstituted C1-C10 heteroalkylene groups, substituted or unsubstituted C6-C12 aryl groups, substituted or unsubstituted C1-C12 heteroaryl groups, and groups containing the solubilizing group; p is selected from 0, 1, and 2; q is selected from any one of 1, 2, and 3, and the sum of p and q is 3; When the functional material is a first functional material, at least one of X and R9 contains the solubilizing group; When the functional material is a second functional material, X is the second coordinating group, and R9 contains the solubilizing group; When the functional material is a third functional material, q is greater than or equal to 2, X is the initiating group, and at least one of the R9 connected to X contains the solubilizing group.

16. The quantum dot material according to any one of claims 1 to 8 and claim 11, characterized in that, The solubilizing groups include ester groups and / or ether groups.

17. A light-emitting device, characterized in that, include: The anode and cathode are set opposite to each other, and A light-emitting layer is located between the anode and the cathode; the material of the light-emitting layer includes a cross-linked quantum dot material formed from the quantum dot material as described in any one of claims 1 to 16.

18. The light-emitting device according to claim 17, characterized in that, The light-emitting device is disposed on the substrate; the cathode is closer to the substrate than the anode.

19. The light-emitting device according to claim 18, characterized in that, The light-emitting device further includes: An electron transport layer is located between the cathode and the light-emitting layer, and is in contact with the light-emitting layer.

20. A method for fabricating a light-emitting device, characterized in that, include: A cathode, an anode, and a light-emitting layer are formed; the cathode and the anode are disposed opposite to each other; the light-emitting layer is located between the anode and the cathode; The material of the light-emitting layer includes a cross-linked quantum dot material formed from quantum dot materials; the quantum dot material includes a quantum dot body and a functional material; the functional material contains aromatic amine groups and solubilizing groups, the solubilizing groups being used to increase the solubility of the functional material in a preset solvent; the ratio between the mass of the functional material and the mass of the quantum dot body is greater than 0 and less than or equal to 0.

45.

21. The method for preparing a light-emitting device according to claim 20, characterized in that, The light-emitting device is formed on the substrate; Forming the light-emitting layer includes: The material of the initial light-emitting layer is spin-coated onto the side of the cathode away from the substrate to form the initial light-emitting layer; the material of the initial light-emitting layer includes the quantum dot material and the preset solvent; Expose the target region of the initial light-emitting layer, causing the exposed portion of the material in the initial light-emitting layer to transform into the cross-linked quantum dot material; and... The initial luminescent layer is developed using a developing solution; the developing solution includes the preset solvent.

22. The method for fabricating a light-emitting device according to claim 21, characterized in that, The material forming the initial luminescent layer includes: mixing the quantum dot bulk, the initial ligand material, and the preset solvent to form a quantum dot stock solution; the ratio between the mass of the initial ligand material and the mass of the quantum dot bulk is greater than 0 and less than or equal to 0.

13. The initial ligand material includes a first ligand material, which is ligandable to the quantum dot body, and the first ligand material contains a first photosensitive group; or, The initial ligand material includes a second functional material, which is ligandable to the quantum dot matrix and contains a second photosensitive group; or, the functional material includes the second functional material. The initial ligand material includes a first ligand material and a second functional material, which are ligand materials and the second functional material can be liganded in the quantum dot body. The first ligand material contains a first photosensitive group, and the functional material includes the second functional material.

23. The method for preparing a light-emitting device according to claim 22, characterized in that, The material forming the initial luminescent layer further includes: adding a first supplementary ligand material to the quantum dot stock solution; the ratio between the mass of the first supplementary ligand material and the mass of the quantum dot bulk is in the range of 0 to 0.35; In the case where the initial ligand material includes the first ligand material, the first supplementary ligand material includes the first ligand material; In the case where the initial ligand material includes the second functional material, the first supplementary ligand material includes the second functional material.

24. The method for preparing a light-emitting device according to claim 21, characterized in that, The material of the initial luminescent layer and / or the developing solution further includes a first functional material; the functional material includes the first functional material; the first functional material is not connected to the quantum dot body.

25. The method for preparing the light-emitting device according to any one of claims 21 to 24, characterized in that, The material of the initial light-emitting layer further includes a third functional material; the functional material includes the third functional material; the third functional material contains at least two initiating groups; In the case where the quantum dot material includes a first ligand material, the initiating group is configured to react with the first photosensitive group under light irradiation, thereby forming the cross-linked quantum dot material from the quantum dot material. When the quantum dot material includes a second functional material, and the second functional material contains a second photosensitive group, the initiating group is configured to react with the second photosensitive group under light irradiation, thereby forming the cross-linked quantum dot material from the quantum dot material.

26. The method for preparing a light-emitting device according to any one of claims 21 to 24, characterized in that, The developing solution further includes a second supplementary ligand material; the ratio between the mass of the second supplementary ligand material in the developing solution and the mass of the quantum dot bulk in the material of the initial luminescent layer is in the range of 0 to 0.

1. In the case where the initial ligand material includes the first ligand material, the second supplementary ligand material includes the first ligand material; In the case where the initial ligand material includes the second functional material, the second supplementary ligand material includes the second functional material.

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