A compound containing hydroxy triarylamine and its application

Abstract

The present application provides a compound containing hydroxyl triarylamine, which can be used as a light extraction material, and its structure is shown in formula (I). In formula (I), hydroxyl groups and benzoxazole or benzothiazole are introduced into the triarylamine main structure of the traditional light extraction layer material. The hydrogen atoms in the hydroxyl group can form intramolecular hydrogen bonds with the heteroatoms on benzoxazole or benzothiazole, thereby improving the planarity of the molecule and increasing the packing density between molecules. At the same time, this intramolecular hydrogen bond undergoes intramolecular proton transfer under light conditions to form a resonance structure. This process converts ultraviolet light energy into heat energy release instead of material deterioration caused by photochemical reactions, thereby reducing the damage caused by ultraviolet light to the device. In addition, the raw materials of the compound are easy to obtain, and it has higher economic value while ensuring good device protection function. The present application also provides an organic electroluminescent device and a display device. #imgabs0#

Description

Technical Field

[0001] The present application relates to the field of organic light-emitting displays, and in particular to a compound, a light extraction material, an organic electroluminescent device, and a display apparatus. Background Art

[0002] An organic electroluminescent device, such as an organic light-emitting diode (OLED), is a multilayer organic thin film structure comprising a light-emitting layer positioned between a cathode and an anode. When the light-emitting layer is energized, a waveguide effect such as total internal reflection occurs between the various film layers, resulting in a reduction in the amount of light transmitted. Adding a high-refractive-index light extraction layer to the transparent electrode can significantly improve light extraction efficiency. The refractive index is the most important indicator of light extraction materials. Generally, the higher the refractive index of the light extraction layer, the higher the light extraction efficiency from the electrode to the light extraction layer, and the higher the OLED's luminous efficiency.

[0003] The various functional layers of OLED are mainly thin films composed of organic matter. These organic films will cause damage to OLED devices under strong ultraviolet rays or long-term exposure to sunlight, affecting the device's luminous performance and accelerating the aging of OLED devices.

[0004] During the OLED manufacturing process, plasma technology is used for flexible packaging. The plasma used in this technology is generated by the principle of glow discharge, which also produces a large amount of ultraviolet light. This strong ultraviolet light can cause damage to OLED devices during the manufacturing process, and the light extraction layer closest to the plasma is the first to bear the brunt of the damage. In addition, ultraviolet light in the atmosphere can damage the device. The light extraction layer with UV absorption function can convert UV light energy into heat energy, thereby protecting the organic layer from damage and reducing the impact of UV light on the device.

[0005] Currently, the light extraction material used in the OLED light extraction layer by Dongjin Semicon Co., Ltd. in South Korea is the aromatic amine compound described in patent CN111217778 A. The refractive index of this type of compound (such as compounds 1-1 and 1-2) still needs to be improved.

[0006]

[0007]

[0008] Furthermore, the light extraction materials used in existing OLEDs have strong absorption in the ultraviolet (UV) band (<400nm). This can lead to photoaging of these materials after prolonged exposure to the atmosphere. This can manifest as increased operating voltage, decreased luminous efficiency, and a shortened lifespan. The light extraction materials in the outer layers of OLEDs are themselves susceptible to aging, making the materials within the OLEDs susceptible to UV light from the plasma glow discharge process and from atmospheric UV light. Summary of the Invention

[0009] In view of the above-mentioned problems of the prior art, the purpose of the present application is to provide a compound, a light extraction material, an organic electroluminescent device and a display device to improve the anti-ultraviolet light performance of the organic electroluminescent device and also improve the luminous efficiency of the organic electroluminescent device.

[0010] The first aspect of the present application provides a compound, the structure of which is shown in formula (I):

[0011]

[0012] in,

[0013] X1-X2 are each independently selected from hydrogen, unsubstituted or Ra-substituted C6-C 30 aryl, unsubstituted or substituted C2-C 30 heteroaryl;

[0014] Y is selected from O or S;

[0015] L1-L3 are each independently selected from a single bond, unsubstituted or Ra-substituted C6-C 30 Arylene, unsubstituted or substituted C2-C 30 Heteroarylene;

[0016] The substituents Ra of each group are independently selected from deuterium, C1-C4 alkyl, C6-C 18 Aryl, C2-C 18 heteroaryl;

[0017] The heteroatoms in the heteroaryl group and the heteroarylene group are each independently selected from O, S, and N.

[0018] A second aspect of the present application provides a light extraction material comprising at least one of the compounds provided in the present application.

[0019] A third aspect of the present application provides an organic electroluminescent device comprising at least one of the light extraction materials provided in the present application.

[0020] A fourth aspect of the present application provides a display device comprising the organic electroluminescent device provided in the present application.

[0021] The compound represented by formula (I) provided in the present application contains benzoxazole or benzothiazole, which can form an intramolecular hydrogen bond structure with hydroxybenzene. This structure undergoes a resonance structure with structural interconversion under the excitation of light. This process can convert the absorbed ultraviolet wavelength light into light of a higher wavelength. After the conversion is completed, the resonance structure is restored to the original molecular connection mode, thereby reducing the photoaging effect of ultraviolet rays on organic electroluminescent devices. In addition, the formation of intramolecular hydrogen bonds increases the stability of the molecular structure. At the same time, the intramolecular hydrogen bonds can increase the bond energy between the hydroxyl hydrogen and the heteroatoms on the benzoxazole or benzothiazole, thereby shortening the spatial distance between the two, making the molecule have good planarity, thereby increasing the packing density of the molecule and improving the light extraction effect.

[0022] Therefore, the organic electroluminescent device of the present application, comprising the compound of the present application, can effectively protect the organic electroluminescent device, reducing damage to the organic electroluminescent device caused by ultraviolet light generated during plasma glow discharge and ultraviolet light in the atmosphere, thereby improving the ultraviolet light tolerance of the organic electroluminescent device, thereby facilitating improved luminous efficiency of the organic electroluminescent device. Furthermore, the light extraction material has a higher refractive index, which can better extract light emitted by the luminescent material within the organic electroluminescent device, thereby improving the luminous efficiency of the organic electroluminescent device. The display device provided by the present application has excellent display effects.

[0023] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0025] Figure 1 A schematic diagram of the structure of a typical organic electroluminescent device. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of this application.

[0027] The first aspect of the present application provides a compound, the structure of which is shown in formula (I):

[0028]

[0029] in,

[0030] X1-X2 are each independently selected from hydrogen, unsubstituted or Ra-substituted C6-C 30 aryl, unsubstituted or substituted C2-C 30 heteroaryl;

[0031] Y is selected from O or S;

[0032] L1-L3 are each independently selected from a single bond, unsubstituted or Ra-substituted C6-C 30 Arylene, unsubstituted or substituted C2-C 30 Heteroarylene;

[0033] The substituents Ra of each group are independently selected from deuterium, C1-C4 alkyl, C6-C 18 Aryl, C2-C 18 heteroaryl;

[0034] The heteroatoms in the heteroaryl group and the heteroarylene group are each independently selected from O, S, and N.

[0035] The inventors of the present application have discovered that the compound represented by formula (I) provided herein contains benzoxazole or benzothiazole, which can form an intramolecular hydrogen bond structure with hydroxybenzene. This structure undergoes a resonance structure with structural interconversion under the excitation of light. This process can convert the absorbed ultraviolet wavelength light into light of a higher wavelength. After the conversion is completed, the resonance structure is restored to the original molecular connection mode, thereby reducing the photoaging of the organic electroluminescent device by ultraviolet rays; in addition, the formation of intramolecular hydrogen bonds increases the stability of the molecular structure; at the same time, the intramolecular hydrogen bonds can increase the bond energy between the hydroxyl hydrogen and the heteroatoms on the benzoxazole or benzothiazole, thereby shortening the spatial distance between the two, making the molecule have good planarity, thereby increasing the packing density of the molecule and improving the light extraction effect.

[0036] Specifically, the structure represented by formula (I) contains benzoxazole or benzothiazole, which can form the following structure A with hydroxybenzene. The hydroxyl group in structure A forms an intramolecular hydrogen bond with a heteroatom on the benzothiazole or benzoxazole. When structure A is excited by light and becomes excited, an excited-state intramolecular proton transfer process occurs, breaking the OH bond of the hydroxyl group and transferring the hydrogen atom to a heteroatom on the benzoxazole or benzothiazole. For example, if the heteroatom is a nitrogen atom, an NH bond is formed, and the aromatic ring atoms form a new resonance structure B as described below. When the resonance structure B de-excites to the ground state, the intramolecular proton transfer process occurs again, generating structure A.

[0037] Because the activation energy during the conversion of resonance structure B is much smaller than that of other photochemical reactions, it has a competitive advantage over other photochemical reactions. It converts hydroxyl groups into keto structures that can be converted into hydroxyl groups. It can absorb ultraviolet light and convert it into visible light, but the parent core structure is not destroyed, and it has good device protection function.

[0038]

[0039] In addition, in formula (I), the N connected to L3 is in the para position of the benzoxazole or benzothiazole linker, forming a linear structure. This structure has low steric hindrance, which is conducive to the close packing of molecules, thereby increasing the refractive index of the light extraction material, which is conducive to the extraction of effective light emitted by the material inside the organic electroluminescent device.

[0040] At the same time, the intermolecular hydrogen bonds behave as attractive forces rather than repulsive forces, making the compound represented by formula (I) have better planarity, thereby further increasing the packing density between molecules and thereby increasing the light extraction efficiency, which is beneficial for extracting the effective light emitted by the internal materials of the organic electroluminescent device.

[0041] Preferably, X1-X2 are each independently selected from hydrogen, C6-C 18 aryl, unsubstituted or substituted C2-C 18 heteroaryl;

[0042] L1-L3 are each independently selected from a single bond, unsubstituted or Ra-substituted C6-C 14 Arylene, unsubstituted or substituted C2-C 14 of heteroarylene.

[0043] Preferably, X1-X2 are each independently selected from hydrogen or any one of the following groups Y1 to Y12:

[0044]

[0045] wherein A1-A6 are each independently selected from O or S;

[0046] The L1-L3 is selected from a single bond or any one of the following groups M1 to M8:

[0047]

[0048] Wherein, A8 is selected from O or S.

[0049] Preferably, X1-X2 are each independently selected from hydrogen or any one of the following groups y1 to y16:

[0050]

[0051] Among them, A9-A 18 Each independently selected from O or S;

[0052] The L1-L3 is selected from a single bond or any one of the following groups m1 to m8:

[0053]

[0054] Among them, A 19 Select from O or S.

[0055] For example, the aforementioned compound is selected from any one of the following compounds A-1 to A-66:

[0056]

[0057]

[0058]

[0059] A second aspect of the present application provides a light extraction material comprising at least one of the compounds provided herein. The compounds provided herein have good ultraviolet light tolerance and a high refractive index. Thus, when applied to a light extraction layer, the light extraction material of the present application can provide good protection for organic electroluminescent devices while maintaining good light extraction efficiency.

[0060] In some embodiments of the present application, the refractive index of the light extraction material is ≥1.91; preferably, the red light refractive index of the light extraction material is ≥1.91, the green light refractive index is ≥2.00, and the blue light refractive index is ≥2.18; more preferably, the red light refractive index of the light extraction material is ≥1.93, the green light refractive index is ≥2.04, and the blue light refractive index is ≥2.25.

[0061] A third aspect of the present application provides an organic electroluminescent device comprising at least one of the light extraction materials provided herein. The compounds provided herein exhibit excellent light extraction capabilities and provide excellent protection for the organic electroluminescent device. Consequently, the organic electroluminescent device provided herein exhibits excellent ultraviolet light tolerance and high luminous efficiency.

[0062] In the present application, there is no particular limitation on the type and structure of the organic electroluminescent device. It can be any organic electroluminescent device of various types and structures known in the art, as long as at least one of the light extraction materials provided in the present application can be used.

[0063] The organic electroluminescent device of the present application may be a light-emitting device with a top-emitting structure, which may include an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a transparent or semi-transparent cathode, and a light extraction layer in sequence on a substrate.

[0064] The organic electroluminescent device of the present application can also be a light-emitting device with a bottom-emitting structure, which can include a light extraction layer, a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode in sequence on a substrate.

[0065] The organic electroluminescent device of the present application can also be a light-emitting device with a double-sided light-emitting structure, which can include a light extraction layer, a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a transparent or semi-transparent cathode, and a light extraction layer in sequence on a substrate.

[0066] In addition, there may be an electron blocking layer between the hole transport layer and the light-emitting layer, and there may be a hole blocking layer between the light-emitting layer and the electron transport layer. However, the structure of the organic electroluminescent device of the present application is not limited to the above-mentioned specific structure. If necessary, the above-mentioned layers can be omitted or increased. The present application has no particular restrictions on the thickness of the above-mentioned layers, as long as the purpose of the present application can be achieved. For example, the organic electroluminescent device can sequentially include an anode (10nm to 1000nm) made of metal oxide or metal on a substrate, a hole injection layer (5nm to 20nm), a hole transport layer (80nm to 140nm), an electron blocking layer (5nm to 20nm), a light-emitting layer (15nm to 40nm), a hole blocking layer (5nm to 20nm), an electron transport layer (25nm to 80nm), an electron injection layer (1nm to 20nm), a transparent or translucent cathode (5nm to 200nm) and a light extraction layer (50nm to 90nm).

[0067] Figure 1 A schematic diagram of a typical organic electroluminescent device is shown, in which, from bottom to top, a substrate 1, a reflective anode electrode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode electrode 8, and a light extraction layer 9 are arranged in sequence.

[0068] I understand. Figure 1 The structure of a typical organic electroluminescent device is only schematically shown. The present application is not limited to this structure. The light extraction material of the present application can be used in any type of organic electroluminescent device.

[0069] In the organic electroluminescent device of the present application, except for the light extraction layer comprising the light extraction material provided in the present application, other layers may use various materials used for the layers in the prior art.

[0070] For convenience, the following reference Figure 1 The organic electroluminescent device of the present application is described, but this does not mean any limitation on the scope of protection of the present application. It is understood that all organic electroluminescent devices that can use the light extraction material of the present application are within the scope of protection of the present application.

[0071] In the present application, the material of the substrate 1 is not particularly limited, and conventional substrates used in organic electroluminescent devices in the prior art can be used, such as glass, polymer materials, glass and polymer materials with thin film transistor (TFT) components, etc.

[0072] In the present application, the material of the reflective anode electrode 2 is not particularly limited and can be selected from transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), low-temperature polycrystalline silicon (LTPS) known in the prior art, or metal materials such as silver and its alloys, aluminum and its alloys, or organic conductive materials such as poly (3,4-ethylenedioxythiophene) (PEDOT), as well as multilayer structures of the above materials.

[0073] In the present application, the material of the hole injection layer 3 is not particularly limited, and hole injection layer materials known in the art can be used, for example, a hole transport material (HTM) can be selected as the hole injection material.

[0074] In the present application, the hole injection layer 3 may further include a p-type dopant. The type of the p-type dopant is not particularly limited, and various p-type dopants known in the art may be used. For example, the p-type dopant may be selected from at least one of the following p-1 to p-3 compounds:

[0075]

[0076] In the present application, the amount of the p-type dopant is not particularly limited and can be an amount known to those skilled in the art.

[0077] In the present application, the material of the hole transport layer 4 is not particularly limited and can be made of hole transport materials (HTMs) known in the art. The number of layers of the hole transport layer 4 is not particularly limited and can be adjusted according to actual needs as long as it can meet the purpose of the present application, for example, 1 layer, 2 layers, 3 layers, 4 layers, or more layers.

[0078] For example, the material for the hole injection layer and the material for the hole transport layer may each be independently selected from, but not limited to, at least one of the following HT-1 to HT-32 compounds:

[0079]

[0080]

[0081]

[0082] In the present application, the light-emitting layer 5 may include a blue light-emitting layer, a green light-emitting layer, or a red light-emitting layer. The light-emitting material in the light-emitting layer 5 is not particularly limited, and various light-emitting materials known to those skilled in the art can be used. For example, the light-emitting material may include a host material and a guest material. In the present application, there is no particular limitation on the amount of the host material and the guest material, and the amounts can be any amount known to those skilled in the art.

[0083] In the present application, the host material of the red light emitting layer is not particularly limited, and at least one of the red light emitting layer host materials known in the art can be used. For example, it can be selected from, but not limited to, at least one of the following RH-1 to RH-13 compounds and GPH-1 to GPH-80 compounds:

[0084]

[0085]

[0086]

[0087]

[0088] In the present application, the host material of the green light emitting layer is not particularly limited, and at least one of the green light emitting layer host materials known in the art can be used. For example, it can be selected from but not limited to at least one of the above-mentioned GPH-1 to GPH-80 compounds.

[0089] In the present application, the host material of the blue light emitting layer is not particularly limited, and at least one of the blue light emitting layer host materials known in the art can be used. For example, it can be selected from but not limited to at least one of the following compounds BH-1 to BH-36:

[0090]

[0091]

[0092]

[0093] In the present application, the guest material of the red light emitting layer is not particularly limited, and at least one of the red light emitting layer guest materials known in the art can be used. For example, it can be selected from, but not limited to, at least one of the following RPD-1 to RPD-28 compounds:

[0094]

[0095]

[0096] In the present application, the guest material of the green light emitting layer is not particularly limited, and at least one of the green light emitting layer guest materials known in the art can be used. For example, it can be selected from but not limited to at least one of the following GD01 to GD04 compounds:

[0097]

[0098] In the present application, the guest material of the blue light emitting layer is not particularly limited, and at least one of the blue light emitting layer guest materials known in the art can be used. For example, it can be selected from but not limited to at least one of the following BD01 to BD04 compounds:

[0099]

[0100] In the present application, the material of the electron transport layer 6 is not particularly limited, and electron transport materials known in the art can be used. For example, known electron transport materials can be selected from but not limited to at least one of the following compounds ET-1 to ET-61:

[0101]

[0102]

[0103]

[0104]

[0105] In the present application, the electron transport layer 6 may further include an n-type dopant. The type of the n-type dopant is not particularly limited, and various n-type dopants known in the art may be used. For example, the following n-type dopants may be used:

[0106]

[0107] In the present application, the amount of the n-type dopant is not particularly limited and can be an amount known to those skilled in the art.

[0108] In the present application, the material of the electron injection layer 7 is metal Yb.

[0109] In the present application, the material of the cathode electrode 8 is not particularly limited, and can be selected from but not limited to magnesium-silver mixture, magnesium-aluminum mixture, LiF / Al, ITO, Al and other metals, metal mixtures, oxides and the like.

[0110] In the present application, the light extraction layer 9 contains at least one of the light extraction materials of the present application. The light extraction layer 9 may also contain a combination of at least one of the light extraction materials of the present application and known light extraction materials. Currently known light extraction materials are mainly light extraction materials containing aromatic amine compounds. In order to improve the light extraction efficiency, the light extraction layer 9 of the present application is arranged on a transparent electrode on the light-extracting side. It is required that the refractive index of the light extraction layer is greater than the refractive index of the electrode and that it can transmit visible light. The light extraction layer 9 of the present application contains the light extraction material of the present application and has a higher refractive index, so it can provide a high light extraction efficiency.

[0111] In some embodiments of the present application, the thickness of the light extraction layer 9 is 50 nm to 90 nm, preferably 60 nm to 90 nm.

[0112] Optionally, the organic electroluminescent device may include an electron blocking layer. In the present application, the material of the electron blocking layer is not particularly limited, and electron blocking layer materials known in the art can be used. For example, it can be selected from, but not limited to, the following EB-1 to EB-5 compounds:

[0113]

[0114] Optionally, the organic electroluminescent device may include a hole blocking layer. In the present application, the material of the hole blocking layer is not particularly limited, and hole blocking layer materials known in the art may be used. For example, it may be selected from, but not limited to, at least one of the above-mentioned compounds ET-1 to ET-61.

[0115] A fourth aspect of the present application provides a display device comprising the organic electroluminescent device provided herein, which has excellent display effects. The display device includes but is not limited to a monitor, a television, a mobile communication terminal, a tablet computer, and the like.

[0116] The present application does not particularly limit the preparation method of the organic electroluminescent device, and any method known in the art may be used. For example, the preparation method of the organic electroluminescent device may include but is not limited to the following steps:

[0117] (1) Cleaning the anode electrode 2 on the substrate 1 of the top-emitting organic electroluminescent device by using a cleaning machine through steps such as chemical cleaning, water cleaning, brush cleaning, high-pressure water cleaning, and air knife cleaning, and then heating treatment;

[0118] (2) vacuum evaporating a hole injection layer 3 on the reflective anode electrode 2, wherein the hole injection layer 3 contains a hole injection material and a p-type dopant;

[0119] (3) vacuum evaporating a hole transport material on the hole injection layer 3 to form a hole transport layer 4;

[0120] (4) vacuum evaporating a light-emitting layer 5 on the hole transport layer 4, wherein the light-emitting layer 5 contains a host material and a guest material;

[0121] (5) vacuum evaporating an electron transport material on the light-emitting layer 5 to form an electron transport layer 6, wherein the electron transport layer 6 comprises an electron transport material and an n-type dopant;

[0122] (6) vacuum evaporating an electron injection material on the electron transport layer 6 to form the electron injection layer 7;

[0123] (7) vacuum evaporating a cathode material on the electron injection layer 7 to form a cathode electrode 8;

[0124] (8) Finally, a light extraction material is evaporated on the cathode electrode 8 to form a light extraction layer 9 .

[0125] The above only describes a typical structure of an organic electroluminescent device and its preparation method. It should be understood that the present application is not limited to this structure.

[0126] Synthesis Example 1: Synthesis of Compound A-18

[0127]

[0128] To a reaction flask, 100 mmol of 4-chloro-2-methoxyphenylboronic acid, 100 mmol of 2-bromobenzothiazole, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of (dibenzylideneacetone)palladium (Pd(dba)) was also added, and the mixture was reacted at 90°C for 12 hours. After completion, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water, and then recrystallized from toluene to obtain a white powder, M1. The amount of Pd(dba) added was 0.6 mol% of the 4-chloro-2-methoxyphenylboronic acid.

[0129] Add 100 mmol of M1, 300 mmol of boron tribromide, and 3 L of dichloromethane to a reaction flask and react at 0°C to 5°C for 12 hours. After completion, stop the reaction, return the reactants to room temperature, add water, and concentrate the organic phase to obtain a white solid. Filter and wash with water, and then recrystallize and purify the resulting solid from toluene to obtain a white powder, M2.

[0130] To a reaction flask, 100 mmol of phenylboric acid, 100 mmol of p-bromoaniline, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of Pd(dba) was also added, and the mixture was reacted at 90°C for 12 hours. After completion, the reaction was stopped, cooled to room temperature, and water was added. The organic phase was concentrated to obtain a white solid, which was filtered and washed with water. The resulting solid was then recrystallized from toluene to obtain a white powder, M4. The amount of Pd(dba) added was 0.6 mol% of the phenylboric acid.

[0131] To a reaction flask, 100 mmol of phenylboric acid, 100 mmol of 3-bromo-7-chlorodibenzothiophene, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of Pd(dba) was also added, and the mixture was reacted at 90°C for 12 hours. After completion, the reaction was stopped, cooled to room temperature, and water was added. The organic phase was concentrated to obtain a white solid, which was filtered and washed with water. The resulting solid was then recrystallized from toluene to obtain M3, a white powder. The amount of Pd(dba) added was 0.6 mol% of the phenylboric acid.

[0132] To a reaction flask, 100 mmol of M4, 100 mmol of M3, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added. 1 mol% of Pd(dba) was also added, and the mixture was allowed to react at 120°C for 12 h. After completion, the reaction was stopped, and the mixture was cooled to room temperature, added with water, filtered, and washed. The resulting solid was recrystallized from toluene to obtain a white powder, M5. The amount of Pd(dba) added was 1 mol% of M3.

[0133] To a reaction flask, 100 mmol of M2, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added, along with 1 mol% of Pd(dba). The mixture was reacted at 120°C for 12 h. After completion, the reaction was stopped and the product was cooled to room temperature, added with water, filtered, and washed with water. The resulting solid was recrystallized and purified from toluene to obtain compound A-18 as a white powder. The amount of Pd(dba) added was 1 mol% of M5.

[0134] 1H NMR(400MHz,Chloroform-d)δ8.28(d,J=6.8Hz,1H),7.99–7.94(m,2H),7.91(dd, J=11.6,7.2Hz,2H),7.65–7.53(m,8H),7.47(d,J=8.0Hz,3H),7.44–7.32(m ,7H),7.15(d,J=7.6,Hz,4H),6.91(d,J=7.2Hz,1H),6.71(d,J=8.0Hz,1H).

[0135] Synthesis Example 2: Synthesis of Compound A-19

[0136]

[0137] To a reaction flask, 100 mmol of 4-chloro-2-methoxyphenylboronic acid, 100 mmol of 2-bromobenzoxazole, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of Pd(dba) was also added, and the mixture was reacted at 90°C for 12 h. After completion, the reaction was stopped, and the mixture was cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water, and then recrystallized from toluene to obtain a white powder, M1. The amount of Pd(dba) added was 0.6 mol% of the 4-chloro-2-methoxyphenylboronic acid.

[0138] Add 100 mmol of M1, 300 mmol of boron tribromide, and 3 L of dichloromethane to a reaction flask and react at 0°C to 5°C for 12 hours. After completion, stop the reaction, return the reactants to room temperature, add water, and concentrate the organic phase to obtain a white solid. Filter and wash with water, and then recrystallize and purify the resulting solid from toluene to obtain a white powder, M2.

[0139] To a reaction flask, 100 mmol of p-chlorophenylboronic acid, 100 mmol of 3-bromodibenzothiophene, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of Pd(dba) was also added, and the mixture was reacted at 90°C for 12 hours. After completion, the reaction was stopped, cooled to room temperature, and water was added. The organic phase was concentrated to obtain a white solid, which was filtered and washed with water. The resulting solid was then recrystallized from toluene to obtain M3, a white powder. The amount of Pd(dba) added was 0.6 mol% of the phenylboronic acid.

[0140] To a reaction flask, 100 mmol of 4-aminobiphenyl, 100 mmol of M3, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added. 1 mol% of Pd(dba) was also added, and the mixture was allowed to react at 120°C for 12 h. After completion, the reaction was stopped, and the mixture was cooled to room temperature, added with water, filtered, and washed. The resulting solid was recrystallized from toluene to obtain M4, a white powder. The amount of Pd(dba) added was 1 mol% relative to the 4-aminobiphenyl.

[0141] To a reaction flask, 100 mmol of M4, 100 mmol of M2, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added, along with 1 mol% of Pd(dba). The mixture was reacted at 120°C for 12 h. After completion, the reaction was stopped and the product was cooled to room temperature, water was added, filtered, and washed. The resulting solid was recrystallized and purified from toluene to obtain compound A-19, a white powder. The amount of Pd(dba) added was 1 mol% of M2.

[0142] 1 H NMR(400MHz,Chloroform-d)δ8.31(d,J=7.6Hz,1H),8.13(d,J=8.4Hz,1H),7.97 (d,J=7.6Hz,1H),7.69(d,J=7.2Hz,1H),7.60(t,J=7.6Hz,4H),7.58–7.49(m,4H),7.38– 7.29(m,10H),7.24–7.18(m,4H),6.90(d,J=7.6Hz,1H),6.66(d,J=8.4Hz,1H).

[0143] Synthesis Example 3: Synthesis of Compound A-30

[0144]

[0145] Add 100 mmol of 2-bromo-1-methoxynaphthalene, 120 mmol of n-butyllithium, 130 mmol of tributyl borate, and 1200 ml of tetrahydrofuran (THF) to a reaction flask. The reaction was allowed to proceed at -85°C for 12 hours. After completion, the reaction was stopped and the mixture was returned to room temperature. Water was added, filtered, and washed. The resulting solid was purified by recrystallization from toluene to obtain a white powder, M1.

[0146] To a reaction flask, add 100 mmol of M1, 100 mmol of 1-bromo-4-chloro-2-fluorobenzene, 27.6 g of potassium carbonate (200 mmol), 2.1 L of toluene, 700 ml of ethanol, and 700 ml of water, followed by 0.6 mol% of Pd(dba). The reaction was refluxed at 95°C for 12 hours. After completion, the reaction was stopped and the mixture was returned to room temperature, water was added, filtered, and washed. The resulting solid was recrystallized from toluene to obtain a white powder, M2. The amount of Pd(dba) added was 0.6 mol% of M1.

[0147] Add 100 mmol of M2, 300 mmol of boron tribromide, and 1.6 L of chloroform to a reaction flask. Incubate at 0°C to 5°C for 12 hours. After completion, stop the reaction, return the mixture to room temperature, add water, filter, and wash. Purify the resulting solid by recrystallization from toluene to obtain M3, a white powder.

[0148] Add 100 mmol of M3, 60.2 g of cesium carbonate (300 mmol), and 2.7 L of N-methylpyrrolidone (NMP) to a reaction flask. The reaction was allowed to proceed at 120°C for 12 hours. After completion, the reaction was stopped and the mixture was returned to room temperature. Water was added, filtered, and washed. The resulting solid was purified by recrystallization from toluene to obtain M4, a white powder.

[0149] In a reaction flask, 100 mmol of M4, 100 mmol of 4-aminophenylboronic acid pinacol ester, 27.6 g of potassium carbonate (200 mmol), 2.5 L of toluene, 800 ml of ethanol, and 800 ml of water were added, and 0.6 mol% of dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium (Pd132) was added. The reaction was refluxed at 95°C for 12 hours. After completion of the reaction, the reaction was stopped and the reactants were returned to room temperature, water was added, filtered, and washed with water. The resulting solid was recrystallized and purified from toluene to obtain a white powder M5. The amount of Pd132 added was 0.6 mol% of M4.

[0150] To a reaction flask, 100 mmol of 4-chlorobiphenyl, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added. 1 mol% of Pd(dba) was also added, and the mixture was reacted at 120°C for 12 hours. After completion, the reaction was stopped, and the mixture was cooled to room temperature, added with water, filtered, and washed. The resulting solid was recrystallized from toluene to obtain M6, a white powder. The amount of Pd(dba) added was 1 mol% relative to the 4-chlorobiphenyl.

[0151] To a reaction flask, 100 mmol of M7, 120 mmol of pinacol diboronate, 19.6 g of potassium acetate (200 mmol), and 2.3 L of toluene were added. Also added were 0.6 mol% of tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 2.4 mol% of 2-dicyclohexylphosphino-2,4,6-triisopropylbiphenyl (xPhos). The reaction was allowed to proceed at 105°C for 12 hours. After completion, the reaction was stopped and the mixture was cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then recrystallized from toluene to obtain M8, a white powder. The amount of Pd2(dba)3 added was 0.6 mol% of M7, and the amount of xPhos added was 2.4 mol% of M7.

[0152] To a reaction flask were added 100 mmol of M8, 100 mmol of 1-bromo-4-chlorobenzene, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water. 1 mol% of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) was also added, and the reaction was incubated at 60°C for 12 h. After completion of the reaction, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid, which was filtered and washed with water. The resulting solid was recrystallized and purified from toluene to obtain a white powder, M9. The amount of Pd(PPh3)4 added was 1 mol% based on the 1-bromo-4-chlorobenzene.

[0153] To a reaction flask, 100 mmol of M6, 100 mmol of M9, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added, along with 1 mol% of Pd(dba). The mixture was reacted at 120°C for 12 h. After completion, the reaction was stopped, and the reactants were cooled to room temperature, added with water, filtered, and washed with water. The resulting solid was recrystallized and purified from toluene to obtain compound A-30, a white powder. The amount of Pd(dba) added was 1 mol% of M9.

[0154] 1 H NMR(400MHz,Chloroform-d)δ8.14(d,J=7.2Hz,1H),7.99–7.90(m,3H),7.86(d, J=7.2Hz,1H),7.79(d,J=7.6Hz,3H),7.71(d,J=7.2Hz,6H),7.63–7.31(m,9H),7.28(d,J=7.2Hz,4H),7.22–7.16(m,6H),7.06(d,J=9.6Hz,1H).

[0155] Synthesis Example 4: Synthesis of Compound A-56

[0156]

[0157] 100 mmol of M1, 120 mmol of pinacol diboronate, 19.6 g of potassium acetate (200 mmol), and 2.3 L of toluene were added to a reaction flask. 0.6 mol% of Pd2(dba)3 and 2.4 mol% of xphos were added, and the reaction was allowed to proceed at 105°C for 12 hours. After the reaction was completed, the reaction was stopped and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water. The obtained solid was recrystallized and purified from toluene to obtain a white powder M2. The amount of Pd2(dba)3 added was 0.6 mol% of M1, and the amount of xphos added was 2.4 mol% of M1.

[0158] To a reaction flask were added 100 mmol of M2, 100 mmol of 1-bromo-4-chlorobenzene, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water. 1 mol% of Pd(PPh3)4 was also added, and the reaction was incubated at 60°C for 12 h. After completion of the reaction, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid, which was filtered and washed with water. The resulting solid was recrystallized and purified from toluene to obtain a white powder, M3. The amount of Pd(PPh3)4 added was 1 mol% of the 1-bromo-4-chlorobenzene.

[0159] To a reaction flask, add 100 mmol of aminobenzene, 100 mmol of M4, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene. Add 1 mol% of Pd(dba) and react at 120°C for 12 hours. After completion, the reaction is stopped and the mixture is cooled to room temperature, added with water, filtered, and washed. The resulting solid is recrystallized from toluene to obtain M5, a white powder. The amount of Pd(dba) added is 1 mol% based on the amount of aminobenzene.

[0160] To a reaction flask, 100 mmol of M3, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added, along with 1 mol% of Pd(dba). The mixture was reacted at 120°C for 12 h. After completion, the reaction was stopped and the product was cooled to room temperature, added with water, filtered, and washed with water. The resulting solid was purified by recrystallization from toluene to obtain compound A-56 as a white powder. The amount of Pd(dba) added was 1 mol% of M5.

[0161] 1H NMR(400MHz,Chloroform-d)δ7.89(d,J=7.6Hz,1H),7.79(d,J=7.2Hz,1H),7.68 (d,J=7.2Hz,1H),7.63–7.56(m,4H),7.50(d,J=9.6Hz,1H),7.46–7.40(m,7H),7. 35–7.24(m,5H),7.18–7.10(m,6H),7.06(d,J=7.2Hz,1H),6.88(d,J=7.2Hz,1H).

[0162] Synthesis Example 5: Synthesis of Compound A-62

[0163]

[0164] To a reaction flask, 100 mmol of p-bromoaniline, 100 mmol of M1, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added. 1 mol% of Pd(PPh3)4 was also added, and the reaction was incubated at 60°C for 12 hours. After completion, the reaction was stopped and the mixture was cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water, and then recrystallized from toluene to obtain a white powder, M2. The amount of Pd(PPh3)4 added was 1 mol% of the p-bromoaniline.

[0165] To a reaction flask were added 100 mmol of 2-bromobenzoxazole, 100 mmol of 4-bromophenylboronic acid, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water. 0.6 mol% of Pd(dba) was also added, and the reaction was incubated at 90°C for 12 h. After completion of the reaction, the reaction was stopped and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water, and the resulting solid was recrystallized from toluene to obtain a white powder, M3. The amount of Pd(dba) added was 0.6 mol% of the 2-bromobenzoxazole.

[0166] 100 mmol of M2, 200 mmol of M3, 200 mmol of sodium tert-butoxide, 1 mol% of Pd2(dba)3, and 4 mol% of xphos were added to a reaction flask and refluxed. After completion of the reaction, the reaction was stopped and the reactants were cooled to room temperature. Water was added and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water. The obtained solid was recrystallized and purified from toluene to obtain a white powder compound A-62. The amount of Pd2(dba)3 added was 1 mol% of M2, and the amount of xphos added was 4 mol% of M2.

[0167] 1H NMR(400MHz,Chloroform-d)δ7.93–7.87(m,4H),7.63(d,J=7.6Hz,1H),7.58–7.52(m,4 H),7.50–7.36(m,10H),7.28(d,J=7.6Hz,1H),7.23–7.15(m,6H),7.06(d,J=8.4Hz,1H).

[0168] Synthesis Example 6: Synthesis of Compound A-66

[0169]

[0170] To a reaction flask, 100 mmol of 2-bromobenzoxazole, 100 mmol of 4-chlorophenylboronic acid, 27.6 g of potassium carbonate (200 mmol), 2 L of toluene, 700 ml of ethanol, and 700 ml of water were added. 0.6 mol% of Pd(dba) was also added, and the reaction was incubated at 90°C for 12 hours. After completion of the reaction, the reaction was stopped and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered and washed with water, and the obtained solid was recrystallized from toluene to obtain a white powder M1. The amount of Pd(dba) added was 0.6 mol% of the 2-bromophenylboronic acid.

[0171] To a reaction flask, 100 mmol of 4-aminobiphenyl, 100 mmol of M1, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added. 1 mol% of Pd(dba) was also added and the mixture was allowed to react at 120°C for 12 h. After completion, the reaction was stopped and the mixture was cooled to room temperature, added with water, filtered, and washed. The resulting solid was recrystallized from toluene to obtain M2, a white powder. The amount of Pd(dba) added was 1 mol% relative to the 4-aminobiphenyl.

[0172] To a reaction flask, 100 mmol of M2, 100 mmol of M3, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added, along with 1 mol% of Pd(dba). The mixture was reacted at 120°C for 12 h. After completion, the reaction was stopped and the product was cooled to room temperature, water was added, filtered, and washed with water. The resulting solid was recrystallized and purified from toluene to obtain compound A-58 as a white powder. The amount of Pd(dba) added was 1 mol% of M2.

[0173] 1H NMR(400MHz,Chloroform-d)δ7.93–7.87(m,2H),7.69–7.56(m,8H),7.49–7.44(m,3H) ,7.46–7.38(m,6H),7.28(dd,J=7.6Hz,2H),7.24–7.16(m,5H),7.06(d,J=8.0Hz,2H).

[0174] Other compounds of the present application can be synthesized by selecting appropriate raw materials according to the ideas of Synthesis Examples 1-6, or by selecting any other appropriate method and raw materials.

[0175] Example 1

[0176] Glass substrates coated with an ITO transparent conductive layer were ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone-ethanol mixed solvent, baked in a clean environment to completely remove moisture, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0177] Then, the glass substrate with the anode having a thickness of 150 nm was placed in a vacuum chamber and evacuated to a vacuum of less than 10 -5 A hole injection layer is vacuum-deposited on the anode layer. The hole injection layer comprises a hole transport material HT-21 and a p-type dopant p-3 at a mass ratio of 3%. The deposition rate is 0.1 nm / s and the deposition film thickness is 10 nm.

[0178] Then, a hole transport material HT-32 was vacuum evaporated on the hole injection layer as a hole transport layer, wherein the evaporation rate was 0.1 nm / s and the evaporation film thickness was 80 nm;

[0179] Then, a light-emitting layer was vacuum-evaporated on the hole transport layer. The light-emitting layer included a host material GHP-16 and a guest material RPD-1. The evaporation was performed using a multi-source co-evaporation method. The evaporation rate of the host material GHP-16 was adjusted to 0.1 nm / s, and the evaporation rate of the guest material RPD-1 was adjusted to 3% of the evaporation rate of the host material GHP-16. The total film thickness was 30 nm.

[0180] Then, an electron transport layer with a thickness of 35 nm was vacuum-deposited on the light-emitting layer. The electron transport layer contained an electron transport material ET-61 and an n-type dopant n-1, wherein the content of the n-type dopant was 50 mol %.

[0181] Then, Yb with a thickness of 1 nm was vacuum evaporated on the electron transport layer as an electron injection layer at a deposition rate of 0.1 nm / s;

[0182] Then, Al with a thickness of 150 nm was evaporated on the electron injection layer as a cathode at a deposition rate of 1 nm / s;

[0183] Finally, a light extraction layer with a thickness of 50 nm was vacuum-evaporated on the cathode electrode. The material of the light extraction layer was A-18.

[0184] The organic electroluminescent device of this embodiment emits red light.

[0185] Examples 2-5

[0186] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Example 1.

[0187] Example 6

[0188] The reaction was the same as in Example 1 except that compound GPH-44 was used instead of GHP-16 and compound GD04 was used instead of RPD-1.

[0189] The organic electroluminescent device of this embodiment emits green light.

[0190] Examples 7-10

[0191] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Example 6.

[0192] Example 11

[0193] The procedure was the same as in Example 1 except that compound BH-1 was used instead of GHP-16 and compound BD01 was used instead of RPD-1.

[0194] The organic electroluminescent device of this embodiment emits blue light.

[0195] Examples 12-15

[0196] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Example 11.

[0197] Examples 16, 19, 22, 25, and 28

[0198] The process was the same as in Example 3 except that Compound A-19, A-30, A-56, A-62, and A-66 were used instead of Compound A-18.

[0199] Examples 17, 20, 23, 26, and 29

[0200] The process was the same as Example 8 except that Compound A-19, A-30, A-56, A-62, and A-66 were used instead of Compound A-18.

[0201] Examples 18, 21, 24, 27, and 30

[0202] The process was the same as Example 13 except that Compound A-19, A-30, A-56, A-62, and A-66 were used instead of Compound A-18.

[0203] Comparative Example 1

[0204] Except that compound 1-1 was used instead of compound A-18, the rest was the same as Example 1.

[0205] Comparative Examples 2-5

[0206] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Comparative Example 1.

[0207] Comparative Example 6

[0208] Except that compound 1-1 was used instead of compound A-18, the rest was the same as Example 6.

[0209] Comparative Examples 7-10

[0210] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Comparative Example 6.

[0211] Comparative Example 11

[0212] Except that compound 1-1 was used instead of compound A-18, the rest was the same as Example 11.

[0213] Comparative Examples 12-15

[0214] Except for adjusting the thickness of the light extraction layer according to Table 1, the rest is the same as Comparative Example 11.

[0215] Comparative Example 16

[0216] Except that compound 1-2 was used instead of compound 1-1, the rest was the same as comparative example 3.

[0217] Comparative Example 17

[0218] Except that compound 1-2 was used instead of compound 1-1, the rest was the same as Comparative Example 8.

[0219] Comparative Example 18

[0220] Except that compound 1-2 was used instead of compound 1-1, the rest was the same as Comparative Example 13.

[0221] Performance testing of organic electroluminescent devices:

[0222] Specifically, the BJV test system is used to test the current efficiency and CIE color coordinates of organic electroluminescent devices.

[0223] For blue light devices, the blue light index (BI) is used to examine their luminous efficiency, and the CIEy value is mainly used to evaluate the saturation of the blue light color. The blue light index is obtained by dividing the current efficiency of the blue light device by the CIEy value. A larger CIEy value indicates that the blue light color has redshifted, and a smaller CIEy value indicates that the blue light color has blueshifted. Current efficiency is used to evaluate the luminous efficiency of green and red light devices. The color changes of green and red light devices are mainly evaluated by the CIEx value. A larger CIEx indicates a redshift of the luminescence, and a smaller CIEx indicates a blueshift of the luminescence.

[0224] Refractive index test:

[0225] The measurement instrument was a Radiation Technology Version-1.0.1.4 spectroscopic ellipsometer; the glass substrate was 200 mm × 200 mm, and the material film thickness was 80 nm. The refractive index (n) of the compound was measured at different wavelengths.

[0226] UV aging test:

[0227] First, the voltage and BI value of the blue organic electroluminescent device are tested and recorded as the initial voltage and initial BI.

[0228] The prepared blue organic electroluminescent device was placed in a QUV-spray UV aging box, using a lamp with a luminous wavelength of 340 nm and a brightness of 0.8 W / m 2 ; The temperature is room temperature; after 16 hours of ultraviolet light irradiation, take it out and place it in a black box to avoid light. The irradiation and light-avoidance process is repeated 5 times, and then the voltage and BI value of the blue organic electroluminescent device are tested, which are recorded as light aging voltage and light aging BI.

[0229] Light aging voltage change = light aging voltage / initial voltage × 100%;

[0230] Photoaging BI change = photoaging BI / initial BI×100%.

[0231] Comparative experiment on photoaging methyl orange degradation:

[0232] Dissolve methyl orange in THF at a concentration of 10 mg / L to create a mother liquor. Dissolve the light extraction material in THF at a concentration of 1 mg / L to create a light extraction material solution. Place 9 ml of the mother liquor in a test tube, then add 1 ml of the light extraction material solution. Vortex to mix thoroughly, and seal the tube to obtain a mixed solution.

[0233] Methyl orange was dissolved in THF to obtain a methyl orange solution having a concentration of 9 mg / L. The absorbance of the methyl orange solution at a wavelength of 460 nm was measured and recorded as the initial absorbance.

[0234] The mixed solution was placed in a QUV-spray UV aging box, using a lamp with a luminous wavelength of 340 nm and a brightness of 0.8 W / m 2 ; The temperature was room temperature; after 18 hours of ultraviolet irradiation, the sample was taken out and the absorbance of the mixed solution at a wavelength of 460 nm was tested and recorded as the absorbance after light aging.

[0235] The performance parameters of each embodiment and comparative example are shown in Table 1-Table 3:

[0236] Table 1 Performance parameters of organic electroluminescent devices

[0237]

[0238]

[0239] Note: “ / ” in Table 1 indicates that there is no corresponding parameter.

[0240] Referring to Table 1, it can be seen from Examples 1 to 30 and Comparative Examples 1 to 18 that, when the light extraction layer has the same thickness, the red light organic electroluminescent device and the green light organic electroluminescent device containing the compound of the present application have a higher current efficiency, and the blue light organic electroluminescent device containing the compound of the present application has a higher blue light index, indicating that the organic electroluminescent device containing the compound provided by the present application has better luminescence performance.

[0241] With respect to the red organic electroluminescent device and the green organic electroluminescent device, it can be seen from Examples 1 to 10 and Comparative Examples 1 to 10 that, at the same light extraction layer thickness, the current efficiency of the organic electroluminescent device obtained in the examples is greater than that of the comparative examples. As the thickness of the light extraction layer changes, the CIEx and CIEy of the red organic electroluminescent device and the green organic electroluminescent device change slightly. At the same time, with respect to the red organic electroluminescent device, for the red organic electroluminescent device containing compound 1-1, the thickness of the light extraction layer increases from 50nm to 90nm, and the current efficiency increases from 42cd / A to 54cd / A, an increase of 12cd / A; while for the red organic electroluminescent device containing compound A-18 provided herein, the current efficiency increases from 45cd / A to 59cd / A, an increase of 14cd / A. Regarding green organic electroluminescent devices, as the light extraction layer thickness increased from 50 nm to 90 nm for green organic electroluminescent devices containing compound 1-1, the current efficiency increased from 122 cd / A to 131 cd / A, a 9 cd / A increase. Meanwhile, for green organic electroluminescent devices containing compound A-18 provided herein, the current efficiency increased from 132 cd / A to 145 cd / A, a 13 cd / A increase. This indicates that, with the same change in light extraction layer thickness, the current efficiency of the red and green organic electroluminescent devices obtained in the examples increased more significantly than that of the comparative examples, indicating that the red and green organic electroluminescent devices containing the compounds provided herein exhibited superior luminescent performance.

[0242] Regarding blue organic electroluminescent devices, as can be seen from Examples 11 to 15 and Comparative Examples 11 to 15, at the same light extraction layer thickness, the blue organic electroluminescent devices obtained in the Examples all exhibited greater BI values than those in the Comparative Examples, while their CIEy values were all lower than those in the Comparative Examples, indicating that the blue light color saturation of the blue organic electroluminescent devices containing the compounds provided herein was higher. For the blue organic electroluminescent device containing Compound 1-1, as the light extraction layer thickness increased from 50 nm to 90 nm, the BI decreased by 12 points from 89 to 77, and the CIEy increased by 0.024 from 0.059 to 0.083. For the blue organic electroluminescent device containing Compound A-18 provided herein, as the light extraction layer thickness increased from 50 nm to 90 nm, the BI decreased by 7 points from 102 to 95, and the CIEy increased by 0.01 points from 0.046 to 0.056. It can be seen that when the thickness of the light extraction layer changes the same, the decrease in BI and the red shift of the blue light of the blue light organic electroluminescent device obtained in the embodiment are smaller than those in the comparative example, indicating that the blue light organic electroluminescent device containing the compound provided in the present application has better luminescence performance and higher luminescent color saturation.

[0243] Table 2 Refractive index and light aging performance parameters of light extraction materials

[0244]

[0245] Referring to Table 2, different light extraction materials have certain differences in their refractive indices at the same wavelength, and the compounds provided in the present application are used as light extraction materials, and their refractive indices of red light, blue light and green light are all higher than those of the comparative example, indicating that the compounds provided in the present application have a higher refractive index when used as light extraction materials.

[0246] After 18 hours of light aging, the absorbance of methyl orange solution for compounds 1-1 and 1-2 decreased from 0.68 to 0.24 and 0.31, respectively, indicating significant decomposition of methyl orange under UV irradiation. The compounds provided herein exhibited absorbances ranging from 0.48 to 0.51, significantly higher than those of compounds 1-1 and 1-2. This demonstrates that the light extraction materials provided herein have UV absorption properties and excellent photostability.

[0247] Table 3 Performance parameters of blue organic electroluminescent devices under UV aging test

[0248]

[0249] Referring to Table 3, the blue organic electroluminescent devices in Comparative Examples 13 and 18 showed a photoaging voltage increase of 3% to 4% and a photoaging BI decrease of 7% to 8% after the photoaging test, indicating that the blue organic electroluminescent devices were significantly aged. The main reason for the decrease in the photoaging BI value may be that the light extraction material aged, resulting in a decrease in transmittance, an increase in the photoaging voltage of the blue organic electroluminescent device, and ultraviolet light damage to the organic layer inside the blue organic electroluminescent device. However, the blue organic electroluminescent devices in Examples 13, 18, 21, 24, 27, and 30 did not show a significant decrease in the photoaging BI, and the photoaging voltage of the blue organic electroluminescent device remained unchanged or increased slightly, indicating that the light extraction material provided in the present application has strong photostability and can also protect the organic layer inside the device, thereby improving the ultraviolet light tolerance of the blue organic electroluminescent device.

[0250] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the scope of protection of the present application.

Claims

1. A compound having a structure as shown in formula (I): in, X1-X2 are each independently selected from any one of the following groups Y1 to Y12: wherein A1-A6 are each independently selected from O or S; Y is selected from O or S; L1 and L2 are selected from any one of the following groups M1 to M8: wherein A8 is selected from O or S; L3 is selected from C6-C 30 Arylene, unsubstituted or substituted C2-C 30 The substituents Ra of each group are independently selected from deuterium, C1-C4 alkyl, C6-C 18 Aryl, C2-C 18 heteroaryl; The heteroatoms in the heteroaryl group and the heteroarylene group are each independently selected from O, S, and N.

2. The compound according to claim 1, wherein L3 is selected from C6-C 14 Arylene, unsubstituted or substituted C2-C 14 of heteroarylene.

3. The compound according to claim 1, wherein The L3 is selected from any one of the following groups M1 to M8: Wherein, A8 is selected from O or S.

4. The compound according to claim 1, wherein X1-X2 are each independently selected from any one of the following groups y1 to y16: Among them, A9-A 18 Each independently selected from O or S; Wherein, the L1-L3 is selected from any one of the following groups m1 to m8: Among them, A 19 Select from O or S.

5. The compound according to claim 1, wherein The compound is selected from any one of the following compounds: 6 . A light extraction material comprising at least one of the compounds according to claim 1 .

7. The light extraction material according to claim 6, wherein The refractive index of the light extraction material is ≥1.

91.

8. The light extraction material according to claim 6, wherein The light extraction material has a red light refractive index of ≥1.91, a green light refractive index of ≥2.00, and a blue light refractive index of ≥2.

18. 9 . An organic electroluminescent device comprising at least one of the light extraction materials according to claim 6 . 10 . A display device comprising the organic electroluminescent device according to claim 9 .

Images