Hole transport material, manufacturing method of light-emitting device and light-emitting device

Abstract

The invention discloses a hole transport material, a manufacturing method of a light-emitting device and the light-emitting device. At least one of an electron donating structure and a peripheral cross-linkable structure of the hole transport material comprises at least one hydrogen bond accepting group; in this way, hydrogen bond acting force stronger than Van der Waals force can be introduced into the cross-linked hole transport material to regulate molecular arrangement, for example, when an electron donating structure comprises at least one hydrogen bond accepting group, intramolecular hydrogen bonds are formed, and the intramolecular hydrogen bonds can enhance molecular planarity and improve hole mobility; for example, the peripheral cross-linkable structure comprises at least one hydrogen bond accepting group to form an intermolecular hydrogen bond, and the intermolecular hydrogen bond can hinder the movement of chain segments in the cross-linked hole transport material, enhance the molecular rigidity and reduce the disorder of a cross-linked network, so that the material is prevented from generating an additional defect mode, and the hole mobility is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a hole transport material, a manufacturing method of a light-emitting device and the light-emitting device. BACKGROUND

[0002] Quantum dot electroluminescent device (QLED) has the advantages of higher color purity, wider color gamut and stronger inorganic material stability, and shows great commercial application potential in the display field. Among them, the fine patterning of the quantum dot light-emitting layer is a key step to realize high-resolution full-color QLED display. The most mature patterning process at present is realized by photolithography technology, which can be generally divided into indirect photolithography and direct photolithography. The indirect photolithography needs to introduce photoresist additionally, and this will inevitably cause problems such as photoresist residue or damage to the quantum dot light-emitting layer when stripping the photoresist. Compared with the indirect photolithography, the direct photolithography changes the solubility of the quantum dot film by photochemical reaction in the quantum dot film under light irradiation, so that the quantum dot light-emitting layer can be finely patterned without photoresist. The direct photolithography greatly reduces the process steps of quantum dot patterning, and is the core technology for the industrialization development of quantum dot display at present. SUMMARY

[0003] Embodiments of the present application provide a hole transport material, a manufacturing method of a light-emitting device and the light-emitting device, which are used to improve the hole mobility of the cross-linked hole transport material. The specific scheme is as follows:

[0004] The hole transport material provided in the embodiments of the present application includes an electron-donating structure and a peripheral cross-linkable structure connected to the electron-donating structure. At least one of the electron-donating structure and the peripheral cross-linkable structure includes at least one hydrogen bond accepting group.

[0005] In a possible implementation manner, in the hole transport material provided in the embodiments of the present application, the electron-donating structure includes a triphenylamine group and a fluorene group, and the peripheral cross-linkable structure includes a carbon chain.

[0006] The triphenylamine group includes a first benzene ring, the fluorene group includes a second benzene ring, the first benzene ring is connected to the second benzene ring, and there is an intramolecular hydrogen bond between the first benzene ring and the second benzene ring.

[0007] In a possible implementation manner, in the hole transport material provided in the embodiments of the present application, the position of the first benzene ring connected to the second benzene ring is a first site, and at least one other site adjacent to the first site in the first benzene ring is a hydrogen bond acceptor.

[0008] In a possible implementation manner, in the hole transport material provided in the embodiments of the present application, the hole transport material includes At least one of them.

[0009] In one possible implementation, in the hole transport material provided in the embodiments of the present invention, the electron-donating structure includes a connected triphenylamine group and a fluorene group, and the peripheral crosslinkable structure includes a carbon chain connected to the fluorene group and a terminal group connected to the carbon chain, wherein the terminal group is a hydrogen bond acceptor.

[0010] In one possible implementation, the hole transport material provided in the embodiments of the present invention includes... At least one of them.

[0011] In one possible implementation, in the hole transport material provided in the embodiments of the present invention, the electron-donating structure includes a triphenylamine group and a carbazole group, wherein the first benzene ring of the triphenylamine group is connected to the N atom of the carbazole group, and the peripheral crosslinkable structure includes a carbon-carbon double bond.

[0012] The position in the first benzene ring connected to the N atom of the carbazole group is the first site, and at least one other site in the first benzene ring adjacent to the first site has an intramolecular hydrogen bond with one of the benzene rings of the carbazole group.

[0013] In one possible implementation, the hole transport material provided in the embodiments of the present invention includes...

[0014] In one possible implementation, in the hole transport material provided in the embodiments of the present invention, the electron-donating structure includes at least two connected carbazole groups, and the peripheral crosslinkable structure includes carbon-carbon double bonds;

[0015] The two benzene rings connected by two adjacent carbazole groups have intramolecular hydrogen bonds.

[0016] In one possible implementation, the hole transport material provided in the embodiments of the present invention includes...

[0017] In one possible implementation, in the hole transport material provided in the embodiments of the present invention, the electron-donating structure includes a connected triphenylamine group and a carbazole group, and the peripheral crosslinkable structure includes a hydrogen bond acceptor group connected to the carbazole group and a crosslinkable group connected to the hydrogen bond acceptor group.

[0018] In one possible implementation, the hole transport material provided in the embodiments of the present invention includes...

[0019] In one possible implementation, in the hole transport material provided in the embodiments of the present invention, the electron-donating structure includes at least two connected carbazole groups, and the peripheral crosslinkable structure includes a hydrogen bond acceptor group connected to the carbazole group and a crosslinkable group connected to the hydrogen bond acceptor group.

[0020] In one possible implementation, the hole transport material provided in the embodiments of the present invention includes...

[0021] Accordingly, embodiments of the present invention also provide a method for manufacturing a light-emitting device, comprising:

[0022] A hole transport material thin film is formed by depositing the hole transport material provided in the embodiments of the present invention on a substrate.

[0023] The target area of ​​the hole transport material film is exposed to cause a cross-linking reaction within the hole transport material in the target area.

[0024] The cross-linked hole transport material film is developed to form a hole transport layer in the target region.

[0025] Accordingly, embodiments of the present invention also provide a light-emitting device, including a hole transport layer, wherein the hole transport layer includes a crosslinkable structure, and the crosslinkable structure has intramolecular hydrogen bonds or intermolecular hydrogen bonds.

[0026] The beneficial effects of the embodiments of the present invention are as follows:

[0027] This invention discloses a hole transport material, a method for fabricating a light-emitting device, and the light-emitting device itself. Due to its peripheral crosslinkable structure, an appropriate crosslinking agent and exposure dosage can be selected to induce a crosslinking reaction in the hole transport material. This allows the hole transport material to meet the requirements of direct photolithography and can be used as a sacrificial layer in the fabrication of patterned quantum dot light-emitting layers. Furthermore, since at least one of the electron-donating structure and the peripheral crosslinkable structure of the hole transport material includes at least one hydrogen bond acceptor group, stronger hydrogen bond forces than van der Waals forces can be introduced into the crosslinked hole transport material to regulate molecular arrangement. For example, when the electron-donating structure includes at least one hydrogen bond acceptor group, intramolecular hydrogen bonds are formed, which can enhance molecular planarity and improve hole mobility. Conversely, when the peripheral crosslinkable structure includes at least one hydrogen bond acceptor group, intermolecular hydrogen bonds are formed. These intermolecular hydrogen bonds can hinder chain segment movement in the crosslinked hole transport material, enhance molecular rigidity, reduce the disorder of the crosslinked network, thereby suppressing the generation of additional defect states and improving hole mobility. Attached Figure Description

[0028] Figure 1 The J (current density)-V (voltage) characteristic curves are shown for single hole transport devices (HODs) prepared using HT materials before and after crosslinking.

[0029] Figure 2 The basic structure of hydrogen bonds;

[0030] Figure 3 This is a schematic diagram of the structure of a hole transport material provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0032] Figure 5 for A schematic diagram of the synthesis route;

[0033] Figure 6 JV characteristic curves of devices with different numbers of hydrogen bonds;

[0034] Figure 7 In order to be in Figure 3 The nuclear magnetic resonance hydrogen spectrum of the hole transport material after introducing hydrogen bonds into the main chain (electron-donating structure) is shown.

[0035] Figure 8 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0036] Figure 9 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0037] Figure 10 To adopt A schematic diagram illustrating the effect of intermolecular hydrogen bonding after the hole transport layer is formed by direct photolithography.

[0038] Figure 11 for A schematic diagram of the synthesis route;

[0039] Figure 12 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0040] Figure 13 for A schematic diagram of the synthesis route;

[0041] Figure 14 In order to be in Figure 12 The nuclear magnetic resonance hydrogen spectrum of the hole transport material after introducing hydrogen bonds into the main chain (electron-donating structure) is shown.

[0042] Figure 15 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0043] Figure 16 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0044] Figure 17 for A schematic diagram of the synthesis route;

[0045] Figure 18 This is a schematic diagram of the structure of another hole transport material provided in an embodiment of the present invention;

[0046] Figure 19 for A schematic diagram of the synthesis route;

[0047] Figure 20 This is a schematic diagram illustrating the intermolecular hydrogen bonds introduced into hole transport materials by infrared spectroscopy. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this invention, mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0050] As used in this invention, “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).

[0051] As used in this invention, "parallel," "perpendicular," and "equal" include the described situation and situations that are similar to the described situation, within an acceptable deviation range, 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 the acceptable deviation range for approximate parallelism can be, for example, within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, within 5°. "Equal" includes absolute equality and approximate equality, where the acceptable deviation range for approximate equality can be, for example, the difference between the two equals being less than or equal to 10% of either one.

[0052] 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.

[0053] This invention describes exemplary embodiments with reference to cross-sectional views and / or plan views as idealized exemplary drawings. In the drawings, for clarity, the thickness of layers and the area of ​​regions are enlarged. 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 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 areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0054] In this invention, circles, triangles, rectangles, trapezoids, pentagons, or hexagons are not strictly defined, but can be approximate circles, triangles, rectangles, trapezoids, pentagons, or hexagons. Small deformations due to tolerances are possible, and chamfers, curved edges, and other deformations are possible.

[0055] In related technologies, when fabricating patterned quantum dot emitting layers using direct photolithography, to meet the requirements of full-color display, it is necessary to repeatedly overlay sub-pixels of the three primary colors (red, green, and blue) within a single pixel area. Considering the color mixing problem, a feasible solution is to introduce a sacrificial layer. For example, in QLED devices with an upright structure (ITO / PEDOT:PSS / HT / QDs / ZnO / Al), the organic hole transport material (HTL) layer preceding the quantum dot emitting layer (QDs) is also processed using direct photolithography. During the development process, the HTL in the unexposed areas is washed away as a sacrificial layer, thereby ensuring that the quantum dot emitting layer does not remain in the unexposed areas.

[0056] The HTL (High-Temperature Layer) sacrificial layer approach effectively solves the color mixing problem in full-color QLED displays fabricated by direct photolithography, but it also introduces new issues. For example, after the hole transport material undergoes an exposure crosslinking process, the material experiences an increase in defect states and a decrease in mobility. Furthermore, in QLED device structures with an organic hole transport layer / QDs / inorganic electron transport layer, the inorganic electron transport material typically exhibits higher electron mobility, leading to a severe imbalance in carrier transport. Therefore, crosslinking the organic hole transport material further degrades the performance of the QLED device.

[0057] like Figure 1 As shown, Figure 1 The J (current density)-V (voltage) characteristic curves of single hole transport devices (HODs) prepared using HT materials before and after crosslinking are shown. Curve C represents HT before crosslinking, and curve D represents HT after crosslinking. It can be seen that the current density of HT materials decreases significantly after exposure crosslinking. According to the space charge confined current (SCLC) theory, the factors that lead to the decrease in current density after exposure crosslinking of HT materials can be attributed to: 1. The hole mobility of HT materials decreases after crosslinking; 2. The defect state density of HT materials increases after crosslinking.

[0058] In view of this, in order to improve the hole mobility of the cross-linked hole transport material and suppress the generation of additional defect states after the cross-linking of the hole transport material, embodiments of the present invention provide a hole transport material, including an electron-donating structure and a peripheral cross-linkable structure connected to the electron-donating structure, wherein at least one of the electron-donating structure and the peripheral cross-linkable structure includes at least one hydrogen bond acceptor group.

[0059] The hole transport material provided in this embodiment of the invention, due to its peripheral crosslinkable structure, allows for the selection of appropriate crosslinking agents and exposure dosages to induce a crosslinking reaction. This enables the hole transport material to meet the requirements of direct photolithography and can be used as a sacrificial layer in quantum dot light-emitting devices to fabricate patterned quantum dot light-emitting layers. Furthermore, since at least one of the electron-donating structure and the peripheral crosslinkable structure of the hole transport material includes at least one hydrogen bond acceptor group, hydrogen bonds can be introduced into the crosslinked hole transport material to regulate molecular arrangement. For example, when the electron-donating structure includes at least one hydrogen bond acceptor group, intramolecular hydrogen bonds are formed, which can enhance molecular planarity and improve hole mobility. Similarly, when the peripheral crosslinkable structure includes at least one hydrogen bond acceptor group, intermolecular hydrogen bonds are formed, which can hinder chain segment movement in the crosslinked hole transport material, enhance molecular rigidity, reduce the disorder of the crosslinked network, thereby suppressing the generation of additional defect states and improving hole mobility.

[0060] Specifically, such as Figure 2 As shown, the basic structure of a hydrogen bond is XH…Y, where X is the hydrogen bond donor and Y is the hydrogen bond acceptor. X and Y are usually highly electronegative atoms, such as N, O, and F, and can exist both intramolecularly and intermolecularly. A hydrogen bond is a stronger interaction force than van der Waals forces. Therefore, by rationally introducing hydrogen bonds, the conformation and arrangement of molecules can be controlled, thereby altering the physicochemical properties of the molecule.

[0061] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 3 and Figure 4 As shown, the electron-donating structure includes triphenylamine groups and fluorene groups, and the peripheral crosslinkable structure includes a carbon chain;

[0062] The triphenylamine group comprises a first benzene ring A1, and the fluorene group comprises a second benzene ring A2. The first benzene ring A1 and the second benzene ring A2 are connected, and there are intramolecular hydrogen bonds between the first benzene ring and the second benzene ring A2. By introducing intramolecular hydrogen bonds between the two benzene rings in the electron-donating structure, the molecular planarity is enhanced through hydrogen bonding, promoting π-π interactions in the hole transport material, thereby increasing the hole mobility of the hole transport material. This facilitates hole transport in light-emitting devices using this hole transport material to fabricate hole transport layers via direct photolithography, thus improving the electron-hole transport balance of the light-emitting device.

[0063] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 3 and Figure 4As shown, the position in the first benzene ring A1 that connects to the second benzene ring A2 is the first point F1. At least one other site in the first benzene ring A1 adjacent to the first point F1 is a hydrogen bond acceptor (e.g., hydrogen bond acceptor site N). For example, the second site F2 adjacent to the first point F1 can be a hydrogen bond acceptor, and the third site F3 adjacent to the first point F1 can also be a hydrogen bond acceptor. In this embodiment of the invention, the second site F2 adjacent to the first point F1 is used as an example of a hydrogen bond acceptor.

[0064] In some embodiments, the hole transport material provided in this disclosure can be an organic polymer material, such as... This structure can utilize a crosslinking agent containing azide, which generates free radicals under light to initiate crosslinking of alkane groups on the side chains of two polymer molecules, thus meeting the requirements of direct photolithography. Furthermore, this structure introduces intramolecular hydrogen bonds into the π bonds of the organic polymer molecule's main chain, suppressing intramolecular π-π twisting and enhancing molecular planarity through these intramolecular hydrogen bonds. Figure 3 As shown, since carrier transport in organic polymer molecules mainly occurs via hopping on π bonds, molecules with greater planarity exhibit stronger π-π interactions, thereby increasing carrier mobility.

[0065] In some embodiments, the hole transport material provided in the present disclosure can be... This structure can also utilize a crosslinking agent containing azide, which generates free radicals under light to initiate crosslinking of alkane groups on the side chains of two polymer molecules, thus meeting the requirements of direct photolithography. Furthermore, this structure introduces intramolecular hydrogen bonds into the π bonds of the organic polymer molecule's main chain, suppressing intramolecular π-π twisting and enhancing molecular planarity through these intramolecular hydrogen bonds. Figure 4 As shown, since carrier transport in organic polymer molecules mainly occurs via hopping on π bonds, molecules with greater planarity exhibit stronger π-π interactions, thereby increasing carrier mobility.

[0066] Specifically, You can have a manufacturer customize it, or you can synthesize it based on existing materials, such as... Figure 5 As shown, Figure 5 for A schematic diagram of the synthesis route. Synthetic route and Figure 5 They are basically the same, the difference lies in... Replace with

[0067] Specifically, based on the regulatory effect of hydrogen bonds on molecular structure, this invention utilizes intramolecular hydrogen bonds to enhance the planarity of the hole transport material, thereby enhancing the π-π interactions of the hole transport material in the QLED device, and thus improving the hole mobility of the hole transport material to promote charge transport in the device. Figure 6 As shown, Figure 6 The JV characteristic curves of devices with different numbers of hydrogen bonds show that the more hydrogen bonds there are, the greater the current density. Therefore, when the hole transport material provided in the embodiments of the present invention is used to fabricate the hole transport layer of the light-emitting device by direct photolithography, the charge transport performance is better.

[0068] like Figure 7 As shown, Figure 7 In order to be in Figure 3 The hydrogen NMR spectrum of the hole transport material after introducing hydrogen bonds into the main chain (electron-donating structure) further proves the use of... Figure 5 The synthetic route shown can be used to prepare of.

[0069] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 8 and Figure 9 As shown, the electron-donating structure includes a linked triphenylamine group and a fluorene group. The peripheral crosslinkable structure includes a carbon chain linked to the fluorene group and a terminal group linked to the carbon chain, with the terminal group acting as a hydrogen bond acceptor. This structure can utilize a crosslinking agent containing azide, which generates free radicals under light to initiate crosslinking of the alkane groups of the carbon chain, thus meeting the requirements of direct photolithography. Since the terminal group is a hydrogen bond acceptor, intermolecular hydrogen bonds can be introduced into the hole transport material. The hydrogen bonding between the two hole transport material molecules hinders the movement of chain segments in the crosslinked hole transport material, enhances molecular rigidity, regulates molecular arrangement to reduce the disorder of the crosslinked network, and suppresses the generation of additional defect states in the material.

[0070] In some embodiments, in the hole transport materials provided in the present disclosure, the hole transport material undergoing intermolecular hydrogen bonding can be an organic polymer, such as... Figure 8 As shown, this organic polymer can be The branched chains in this organic polymer N in the figure represents a hydrogen bond acceptor, which is a branched structure in this organic polymer. The nitrogen in N can be found on the side chains of other organic polymers. The H in the H group forms intermolecular hydrogen bonds, or it can be a branch of the organic polymer. The nitrogen in N forms intermolecular hydrogen bonds with the alkyl hydrogens of the branched carbon chains in other organic polymers, such as... Figure 10 As shown, Figure 10 To adopt A schematic diagram illustrating the effect of intermolecular hydrogen bonding after the hole transport layer is formed by direct photolithography.

[0071] In some embodiments, the organic polymer in the hole transport material provided in the present disclosure embodiments may also be an organic polymer that undergoes intermolecular hydrogen bonding. like Figure 9 As shown, the principle of intermolecular hydrogen bonding in this structure is similar to... Figure 8 The structure shown forms intermolecular hydrogen bonds in the same way.

[0072] Specifically, You can have a manufacturer customize it, or you can synthesize it based on existing materials, such as... Figure 11 As shown, Figure 11 for A schematic diagram of the synthesis route. Synthetic route and Figure 11 They are basically the same, the difference lies in... Replace with

[0073] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 12 As shown, the electron-donating structure includes a triphenylamine group and a carbazole group. The first benzene ring A1 of the triphenylamine group is connected to the N atom of the carbazole group, and the peripheral crosslinkable structure includes a carbon-carbon double bond.

[0074] The position where the N atom of the carbazole group is attached to the first benzene ring A1 is designated as point F1. At least one other site (e.g., second site F2 and third site F3) adjacent to point F1 in the first benzene ring A1 has an intramolecular hydrogen bond with one of the benzene rings in the carbazole group. By introducing intramolecular hydrogen bonds between the two benzene rings in the electron-donating structure, the molecular planarity is enhanced through hydrogen bonding, promoting π-π interactions in the hole transport material, thereby increasing the hole mobility of the hole transport material. This facilitates hole transport in light-emitting devices using this hole transport material to fabricate hole transport layers via direct photolithography, thus improving the electron-hole transport balance of the light-emitting device.

[0075] In some embodiments, the hole transport material provided in the present disclosure can be a small molecule material, such as... This structure allows for the selection of suitable crosslinking agents to initiate carbon-carbon double bond crosslinking under light irradiation, thus meeting the requirements of direct photolithography. Furthermore, the introduction of intramolecular hydrogen bonds into this small molecule material inhibits intramolecular π-π twisting, enhances molecular planarity, promotes π-π interactions in hole transport materials, and improves hole mobility. Figure 12 As shown.

[0076] Specifically, You can either have a manufacturer customize it, or you can synthesize it using existing materials, such as... Figure 13 As shown, Figure 13 for A schematic diagram of the synthesis route.

[0077] like Figure 14 As shown, Figure 14 In order to be in Figure 12 The hydrogen NMR spectrum of the hole transport material after introducing hydrogen bonds into the main chain (electron-donating structure) further proves the use of... Figure 13 The synthetic route shown can be used to prepare of.

[0078] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 15 As shown, the electron-donating structure includes at least two connected carbazole groups, and the peripheral crosslinkable structure includes carbon-carbon double bonds;

[0079] The two benzene rings (A1 and A2) connected by two adjacent carbazole groups have intramolecular hydrogen bonds. By introducing intramolecular hydrogen bonds between the two benzene rings in the electron-donating structure, the molecular planarity is enhanced through hydrogen bonding, promoting π-π interactions in the hole transport material, thereby increasing the hole mobility of the hole transport material. This facilitates hole transport in light-emitting devices using this hole transport material to fabricate hole transport layers via direct photolithography, thus improving the electron-hole transport balance of the light-emitting device.

[0080] In some embodiments, the hole transport material provided in the present disclosure can be a small molecule material, such as... This structure allows for the selection of suitable crosslinking agents to initiate carbon-carbon double bond crosslinking under light irradiation, thus meeting the requirements of direct photolithography. Furthermore, the introduction of intramolecular hydrogen bonds into this small molecule material inhibits intramolecular π-π twisting, enhances molecular planarity, promotes π-π interactions in hole transport materials, and improves hole mobility. Figure 15 As shown.

[0081] Specifically, You can either have a manufacturer design it, or you can synthesize it using existing materials. The synthesis route is the same as... Figure 13 They are basically the same, the difference lies in the raw materials. The reaction conditions are the same.

[0082] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 16 As shown, the electron-donating structure includes a linked triphenylamine group and a carbazole group, and the peripheral crosslinkable structure includes a hydrogen bond acceptor group (e.g., a hydrogen bond acceptor group linked to the carbazole group) connected to the carbazole group. The structure includes a crosslinkable group (e.g., a carbon-carbon double bond) connected to a hydrogen bond acceptor group. A suitable crosslinking agent can be selected to initiate carbon-carbon double bond crosslinking under light irradiation, thus meeting the requirements of direct photolithography. Since the peripheral crosslinkable structure includes a hydrogen bond acceptor group connected to a carbazole group, intermolecular hydrogen bonds can be introduced into the hole transport material. The hydrogen bonding between the two hole transport material molecules hinders chain segment movement in the crosslinked hole transport material, enhancing molecular rigidity, regulating molecular arrangement to reduce the disorder of the crosslinked network, and suppressing the generation of additional defect states in the material.

[0083] In some embodiments, the hole transport material provided in this disclosure can be a small molecule material, such as including... The small molecule material has a cross-linkable outer structure. N in the figure represents a hydrogen bond acceptor, and one of the small molecule materials contains... The N in it can be in other small molecule materials The H in the molecules forms intermolecular hydrogen bonds, or it can be a single hydrogen bond in this small molecule material. The N in the N-molecule forms intermolecular hydrogen bonds with the alkyl H-molecules in the carbon chains of other small molecule materials.

[0084] Specifically, You can have a manufacturer customize it, or you can synthesize it based on existing materials, such as... Figure 17 As shown, Figure 17 for A schematic diagram of the synthesis route.

[0085] In some embodiments, in the hole transport materials provided in the present disclosure, such as Figure 18 As shown, the electron-donating structure includes at least two connected carbazole groups, and the peripheral crosslinkable structure includes hydrogen bond accepting groups (e.g., connected to the carbazole groups) The structure includes a crosslinkable group (e.g., a carbon-carbon double bond) connected to a hydrogen bond acceptor group. A suitable crosslinking agent can be selected to initiate carbon-carbon double bond crosslinking under light irradiation, thus meeting the requirements of direct photolithography. Since the peripheral crosslinkable structure includes a hydrogen bond acceptor group connected to a carbazole group, intermolecular hydrogen bonds can be introduced into the hole transport material. The hydrogen bonding between the two hole transport material molecules hinders chain segment movement in the crosslinked hole transport material, enhancing molecular rigidity, regulating molecular arrangement to reduce the disorder of the crosslinked network, and suppressing the generation of additional defect states in the material.

[0086] In some embodiments, the hole transport material provided in the present disclosure can be a small molecule material, such as... The small molecule material has a cross-linkable outer structure. N in the figure represents a hydrogen bond acceptor, and one of the small molecule materials contains... The N in it can be in other small molecule materials The H in the molecules forms intermolecular hydrogen bonds, or it can be a single hydrogen bond in this small molecule material. The N in the N-molecule forms intermolecular hydrogen bonds with the alkyl H-molecules in the carbon chains of other small molecule materials.

[0087] Specifically, You can have a manufacturer customize it, or you can synthesize it based on existing materials, such as... Figure 19 As shown, Figure 19 for A schematic diagram of the synthesis route.

[0088] It should be noted that the hole transport materials provided in the embodiments of the present invention are all formed by introducing N atoms into the electron-donating structure or the peripheral crosslinkable structure to form hydrogen bond acceptor groups. Of course, other highly electronegative atoms such as O and F can also be introduced into the electron-donating structure or the peripheral crosslinkable structure.

[0089] Specifically, the hydrogen bonds introduced in the hole transport materials provided in the embodiments of the present invention can be characterized by infrared spectroscopy. Taking the formation of intermolecular hydrogen bonds as an example, for instance... Figure 20 As shown, curve E represents the hydrogen bond donor, curve F represents the hydrogen bond acceptor, and curve G represents the effect of intermolecular hydrogen bond formation in the Fourier transform infrared spectrum. The formation of hydrogen bonds reduces the bond force constant between the hydrogen atom and its bonded atoms, lowering the vibrational frequency and causing the infrared absorption peak to shift to a lower wavenumber (redshift). Furthermore, the presence of hydrogen bonds can increase the absorption intensity of the corresponding vibrational modes and broaden the absorption peak; these changes further reflect the strength and number of hydrogen bonds themselves.

[0090] Specifically, the hydrogen bonds introduced in the hole transport materials provided in the embodiments of the present invention can be characterized by various experimental methods, such as nuclear magnetic resonance (NMR), X-ray crystallography, and molecular dynamics simulations, as well as infrared spectroscopy. X-ray crystallography determines the presence and type of hydrogen bonds by measuring the distances between atoms in the molecular crystal structure. Nuclear magnetic resonance (NMR) analysis shows that the weakening of the bond and the increase in bond length during hydrogen bond formation can cause changes in the local chemical and electronic environment of the relevant protons and atomic nuclei. Thus, NMR spectroscopy can observe changes in the chemical shift and linearity of the atomic nuclei forming the hydrogen bonds, proving the formation of hydrogen bonds.

[0091] Based on the same inventive concept, embodiments of the present invention also provide a method for manufacturing a light-emitting device, comprising:

[0092] A hole transport material thin film is formed by depositing the hole transport material provided in the embodiments of the present invention on a substrate.

[0093] The target area of ​​the hole transport material film is exposed to cause a cross-linking reaction within the hole transport material in the target area;

[0094] The cross-linked hole transport material film is developed to form a hole transport layer in the target area.

[0095] The fabrication method provided in this embodiment of the invention forms a hole transport layer using direct photolithography. Since the hole transport material is one of the aforementioned hole transport materials, meaning that at least one of its electron-donating structure and peripheral crosslinkable structure includes at least one hydrogen bond acceptor group, stronger hydrogen bond forces than van der Waals forces can be introduced into the crosslinked hole transport layer to regulate molecular arrangement. For example, when the electron-donating structure includes at least one hydrogen bond acceptor group, intramolecular hydrogen bonds are formed, which can enhance molecular planarity and increase hole mobility. Conversely, when the peripheral crosslinkable structure includes at least one hydrogen bond acceptor group, intermolecular hydrogen bonds are formed, which can hinder chain segment movement in the crosslinked hole transport material, enhance molecular rigidity, reduce the disorder of the crosslinked network, thereby suppressing the generation of additional defect states and improving hole mobility.

[0096] Specifically, the fabrication method provided in this embodiment of the invention may further include coating a crosslinkable quantum dot material on the side of the hole transport material film away from the substrate after depositing and forming the hole transport material film and before exposing the target area of ​​the hole transport material film. In this way, the quantum dot light-emitting layer and the hole transport layer can be formed by direct photolithography, and the hole transport layer, as a sacrificial layer of the quantum dot light-emitting layer, can improve the hole transport mobility while preventing cross-coloring.

[0097] Optionally, the quantum dot material may include a quantum dot body and a quantum dot ligand, wherein the quantum dot body and the coordinating groups in the quantum dot ligand are connected by chemical bonds.

[0098] Optionally, the quantum dot body includes any one of the following: group IIB-VIA quantum dots, group IIIA-VA quantum dots, group IVA-VIA quantum dots, core-shell structured quantum dots, and ABX3 type perovskite quantum dots. In ABX3 type perovskite quantum dots, A is CH3NH3. + (methylamine), NH2CH=NH2 (formamidinium) and Cs + One or more of them, where B is Pb 2+ and Sn 2+ One or two of them, X is Cl - ,Br - and I -One or more of the following, ABX3 type perovskite quantum dots include CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3, CsPbBr3, CsPbCl3 and CsPbI3.

[0099] For example, group IIB-VIA quantum dots are selected from: one or more binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and MgS; and ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, and CdZn Te, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto.

[0100] IIIA-VA group quantum dots are selected from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but not limited thereto.

[0101] Group IVA-VIA quantum dots are selected from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto. Group IVA-VIA quantum dots are selected from, for example, elemental (monological) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto.

[0102] 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 is made of CdS and the shell is made of ZnS.

[0103] In other embodiments, the quantum dot bulk can be other nanoscale materials, such as nanorods, nanosheets, etc. The composition of these other nanoscale materials may include at least one of the following: CdS, CdSe, CdTe, ZnSe, InP, PbS, CuInS2, ZnO, CsPbCl3, CsPbBr3, CsPhI3, CdS / ZnS, CdSe / ZnS, ZnSe, InP / ZnS, PbS / ZnS, InAs, InGaAs, InGaN, GaNk, ZnTe, Si, Ge, and C.

[0104] For example, the quantum dot body can include cadmium-free (Cd) quantum dots. Cadmium-free quantum dots are quantum dots that do not contain cadmium (Cd). Cadmium (Cd) can cause serious environmental / health problems, so cadmium-free quantum dots can be used effectively.

[0105] Optionally, the shape of the quantum dot material includes, but is not limited to, quantum dot materials of any geometric shape such as sphere, spherical, ellipsoidal, polyhedral, rod-shaped, cross-shaped, and ring-shaped.

[0106] In some embodiments, the fabrication method of the light-emitting device provided in the present invention may also include other film layers, such as an anode, an electron transport layer, a cathode, etc. The materials, thicknesses and fabrication methods of these film layers are the same as those in the prior art, and will not be described in detail here.

[0107] Based on the same inventive concept, embodiments of the present invention also provide a light-emitting device, including a hole transport layer. The hole transport layer includes a crosslinkable structure, and the crosslinkable structure contains intramolecular hydrogen bonds or intermolecular hydrogen bonds. Specifically, the hole transport layer in this light-emitting device can be formed by directly photolithography using the aforementioned hole transport material and quantum dot material. The formed intramolecular or intermolecular hydrogen bonds can be found in the relevant description of the aforementioned hole transport material, and will not be repeated here.

[0108] Specifically, the light-emitting device provided in this embodiment of the invention may further include: a substrate located on one side of the hole transport layer, an anode located between the substrate and the hole transport layer, a hole injection layer located between the anode and the hole transport layer, a quantum dot light-emitting layer located on the side of the hole transport layer facing away from the substrate, an electron transport layer located on the side of the quantum dot light-emitting layer facing away from the substrate, and a cathode located on the side of the electron transport layer facing away from the substrate. The materials and thicknesses of these films can be fabricated using the same methods as in the prior art, and will not be described in detail here.

[0109] This invention provides a hole transport material, a method for fabricating a light-emitting device, and the light-emitting device itself. Due to its peripheral crosslinkable structure, an appropriate crosslinking agent and exposure dosage can be selected to induce a crosslinking reaction in the hole transport material. This allows the hole transport material to meet the requirements of direct photolithography and can be used as a sacrificial layer in a quantum dot light-emitting device to fabricate a patterned quantum dot light-emitting layer. Furthermore, since at least one of the electron-donating structure and the peripheral crosslinkable structure of the hole transport material includes at least one hydrogen bond acceptor group, stronger hydrogen bond forces than van der Waals forces can be introduced into the crosslinked hole transport material to regulate molecular arrangement. For example, when the electron-donating structure includes at least one hydrogen bond acceptor group, intramolecular hydrogen bonds are formed, which can enhance molecular planarity and improve hole mobility. Conversely, when the peripheral crosslinkable structure includes at least one hydrogen bond acceptor group, intermolecular hydrogen bonds are formed. These intermolecular hydrogen bonds can hinder chain segment movement in the crosslinked hole transport material, enhance molecular rigidity, reduce the disorder of the crosslinked network, thereby suppressing the generation of additional defect states and improving hole mobility.

[0110] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A hole transporting material, characterized by, The electron donating structure and the peripheral cross-linkable structure each include at least one hydrogen bond accepting group.

2. The hole transport material according to claim 1, wherein The electron donating structure includes a triphenylamine group and a fluorene group, and the peripheral cross-linkable structure includes a carbon chain; The first benzene ring and the second benzene ring are connected, and there is an intramolecular hydrogen bond between the first benzene ring and the second benzene ring.

3. The hole transporting material according to claim 2, wherein The position of the first benzene ring connected with the second benzene ring is a first site, and at least one other site adjacent to the first site in the first benzene ring is a hydrogen bond acceptor.

4. The hole transporting material according to claim 3, wherein The hole transport material includes at least one of 5. The hole transporting material according to claim 1, wherein The electron donating structure includes a triphenylamine group and a fluorene group, and the peripheral cross-linkable structure includes a carbon chain connected with the fluorene group and a terminal group connected with the carbon chain, and the terminal group is a hydrogen bond acceptor.

6. The hole transporting material according to claim 5, wherein The hole transport material includes at least one of 7. The hole transport material of claim 1, wherein The electron donating structure includes a triphenylamine group and a carbazole group, and a first benzene ring of the triphenylamine group is connected with an N atom of the carbazole group, and the peripheral cross-linkable structure includes a carbon-carbon double bond. The position of the first benzene ring connected with the N atom of the carbazole group is a first site, and there is an intramolecular hydrogen bond between at least one other site adjacent to the first site in the first benzene ring and one benzene ring in the carbazole group.

8. The hole transport material according to claim 7, wherein The hole transport material comprises 9. The hole transporting material according to claim 1, wherein The electron donating structure includes at least two connected carbazole groups, and the peripheral cross-linkable structure includes a carbon-carbon double bond. There is an intramolecular hydrogen bond between the two benzene rings connected with each other of the two adjacent carbazole groups.

10. The hole transport material according to claim 9, wherein The hole transport material comprises 11. The hole transport material of claim 1, wherein The electron donating structure includes a triphenylamine group and a carbazole group connected, and the peripheral cross-linkable structure includes a hydrogen bond accepting group connected with the carbazole group and a cross-linkable group connected with the hydrogen bond accepting group.

12. The hole transport material of claim 11, wherein, The hole transport material comprises 13. The hole transport material of claim 1, wherein The electron donating structure includes at least two connected carbazole groups, and the peripheral cross-linkable structure includes a hydrogen bond accepting group connected with the carbazole group and a cross-linkable group connected with the hydrogen bond accepting group.

14. The hole transport material of claim 13, wherein, The hole transport material comprises 15. A method for manufacturing a light-emitting device, characterized in that, It includes: Depositing a hole transport material as claimed in any one of claims 1-14 on a substrate to form a hole transport material thin film; Exposing a target area of the hole transport material thin film to cause a cross-linking reaction in the hole transport material of the target area; Developing the hole transport material thin film after cross-linking to form a hole transport layer in the target area.

16. A light-emitting device, characterized in that, It includes a hole transport layer, and the hole transport layer includes a cross-linkable structure having an intramolecular hydrogen bond or an intermolecular hydrogen bond.

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