Host material, method for preparing the same, dual-host material, and organic electroluminescent device

Abstract

This invention relates to the field of organic electroluminescent materials technology, specifically to host materials, their preparation methods, dual host materials, and organic electroluminescent devices. The host material is selected from the following compounds: X1 and Y1, where either X1 or Y1 is CR3, and the other is Si(R1)(R2); ring A is C6-C14 aryl; L1, L2, and L3 are each independently selected from any one of the following: linking bonds, C6-C30 arylene, C6-C30 heteroarylene, and C10-C30 fused ring groups. The host material can be combined with a second host material containing triazine, thereby forming a dual host material where triplet excitons are dispersed on both host materials, reducing triplet-triplet annihilation (TTA). When both are used as host materials for the emitting layer, the driving voltage of the organic electroluminescent device is reduced while the efficiency and lifetime of the organic electroluminescent device are improved.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials technology, and more specifically, to host materials, their preparation methods, dual host materials, and organic electroluminescent devices. Background Technology

[0002] OLED (Organic Light Emitting Display) refers to the phenomenon where organic semiconductor materials and light-emitting materials emit light through carrier injection and recombination under an electric field. The principle involves using an ITO transparent electrode and a metal electrode as the anode and cathode, respectively. Under a certain voltage, electrons and holes are injected from the cathode and anode into the electron transport layer and hole transport layer, respectively. They then migrate through the electron and hole transport layers to the light-emitting layer, where they meet, forming excitons and exciting the light-emitting molecules. These molecules then emit visible light through radiative relaxation. However, a single host material often struggles to simultaneously achieve efficient transport and balanced injection of both holes and electrons. For example, hole-transporting host materials typically have higher highest occupied molecular orbital energy levels, which is beneficial for hole injection but has poor electron injection capabilities; conversely, electron-transporting host materials are less conducive to hole injection. This imbalance in carrier transport causes the exciton recombination region to deviate from the center of the light-emitting layer, and may even cause excitons to recombine at the electron transport layer / hole transport layer interface, resulting in efficiency loss and reduced lifetime of organic electroluminescent devices.

[0003] To overcome the limitations of a single host material, two complementary host materials are typically used simultaneously in a single emitting layer: one is a hole-transporting host, and the other is an electron-transporting host. This strategy aims to achieve a more balanced carrier injection and transport through the synergistic effect of the two materials, widening the exciton recombination region and thus improving the device's efficiency and stability. However, existing dual-host systems still have some unresolved issues. First, the compatibility between the two host materials and their energy level matching with the guest material are crucial. Poor compatibility can easily lead to phase separation in the thin film, affecting the device's uniformity and stability. Second, while some dual-host systems improve carrier balance to some extent, unfavorable energy transfer may exist between the two host materials, or the triplet energy level of one host may be insufficient to effectively confine the triplet excitons of the guest material, causing triplet-triplet annihilation or exciton quenching, which in turn limits further improvement in device performance.

[0004] Therefore, developing a novel dual-host material system that can not only achieve efficient and balanced transport of holes and electrons, but also possesses excellent energy level matching and efficient exciton confinement capabilities is of vital importance for promoting the commercialization of high-performance, long-life OLED devices.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a host material, its preparation method, a dual host material, and an organic electroluminescent device. Embodiments of this invention provide a novel host material that can be combined with a second host material containing triazine, thereby enabling the formation of a dual host material where triplet excitons are dispersed on both host materials, reducing triplet-triplet annihilation (TTA). When both are used as host materials for the emitting layer, the driving voltage of the organic electroluminescent device is reduced while simultaneously improving its efficiency and lifetime.

[0007] This invention is implemented as follows: In a first aspect, embodiments of the present invention provide a main material selected from compounds represented by Formula I: In this context, either X1 or Y1 is CR3, and the other is Si(R1)(R2); R1, R2, and R3 each independently represent substituted or unsubstituted C1-C10 alkyl or substituted or unsubstituted C6-C10 aryl. Ring A is a substituted or unsubstituted C6-C14 aryl group; L1, L2 and L3 are each independently selected from any one of the following: linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C6-C30 heteroarylene and substituted or unsubstituted C10-C30 fused ring group; R4 and R5 are each independently selected from any one of hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted tetraphenylsilyl, and substituted or unsubstituted C10-C30 fused ring group.

[0008] Secondly, embodiments of the present invention provide a dual-body material, comprising a second body material and a first body material, wherein the first body material is selected from the aforementioned body materials, and the second body material is selected from compounds represented by Formula II: D1, D2 and D3 are each independently selected from any one of substituted or unsubstituted C6-C42 aryl and substituted or unsubstituted C6-C30 heteroaryl; L4, L5, and L6 are each independently selected from the linking bond, substituted or unsubstituted C6-C18 aryl groups.

[0009] Thirdly, embodiments of the present invention provide a method for preparing a main material, which is synthesized according to the following synthetic route: ; Preferably, intermediate M is synthesized according to the following synthetic pathway: .

[0010] Fourthly, embodiments of the present invention provide an organic electroluminescent device, which includes a light-emitting layer formed from the aforementioned dual host materials.

[0011] The present invention has the following beneficial effects: In the host material provided by the embodiments of the present invention, isosilazole and aryl groups are fused to form a rigid planar large π-conjugated structure, which effectively enhances electron transport capability. The connection of the triarylamine structure forms an intramolecular "donor-acceptor" structure, which can effectively regulate the HOMO and LUMO energy levels of the molecule. The covalent connection between the two gives the molecule bipolar transport characteristics, and the rigid fused ring structure brings high glass transition temperature and thermal decomposition temperature, extending the lifespan of organic electroluminescent devices. Simultaneously, this host material, combined with a second host material containing triazine, forms a dual host material that allows triplet excitons to be dispersed on both host materials, reducing triplet-triplet annihilation (TTA). When both are used as host materials for the light-emitting layer, the driving voltage of the organic electroluminescent device is reduced while simultaneously improving the efficiency and lifespan of the organic electroluminescent device. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 The NMR spectrum of the main material provided in Embodiment 1 of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0015] In a first aspect, embodiments of the present invention provide a host material selected from compounds represented by Formula I: In this system, either X1 or Y1 is CR3, and the other is Si(R1)(R2); R1, R2, and R3 each independently represent any one of substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C12 aryl; ring A is substituted or unsubstituted C6-C14 aryl; L1, L2, and L3 each independently represent any one of a linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C6-C30 heteroarylene, and substituted or unsubstituted C10-C30 fused ring; R4 and R5 each independently represent any one of hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted tetraphenylsilyl, and substituted or unsubstituted C10-C30 fused ring.

[0016] Furthermore, R4 and R5 are each independently selected from any one of hydrogen, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted tetraphenylsilyl, and substituted or unsubstituted C10-C20 fused ring groups. For example, each independently selected from any one of the groups shown in the following structural formulas:

[0017] .

[0018] Furthermore, L1, L2, and L3 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 arylene, a substituted or unsubstituted C6-C24 heteroarylene, or a substituted or unsubstituted C10-C20 fused ring group.

[0019] Furthermore, all hydrogen atoms in the compound shown in Formula I can be independently substituted with deuterium. That is, all hydrogen atoms in the compound shown in Formula I can be partially substituted with deuterium, completely substituted with deuterium, or not substituted with deuterium.

[0020] It should be noted that "substituted or unsubstituted" means that the group may not be substituted, or may be substituted by one or more substituents. The "substitution" refers to the hydrogen atom bonded to the carbon atom of the compound becoming another substituent, and there is no restriction on the position of substitution, as long as the position is where the hydrogen atom is substituted, that is, the position where the substituent can be substituted. When two or more substituents are substituted, the two or more substituents may be the same as or different from each other.

[0021] The substituents in "substituted or unsubstituted" are selected from fluorine, cyano, C1-C10 alkyl, C3-C20 cycloalkyl, and C3-C20 heterocycloalkyl, and the heteroatoms are selected from one or more of oxygen, nitrogen, sulfur, selenium, phosphorus, and silicon.

[0022] Furthermore, the host material is selected from any one of the compounds shown in the following structural formulas: .

[0023] It should be noted that the compounds shown in the above structural formulas are only some specific structural forms of the host material, and are not limited to these chemical structures. All compounds based on structural formula I, with simple transformations of groups within the defined range, should be included.

[0024] Secondly, embodiments of the present invention provide a method for preparing a host material, comprising: synthesizing intermediate M according to the following synthetic pathway: The specific process is as follows: Under a protective gas (e.g., nitrogen) system, reactant 1 (1 eq), reactant 2 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-5 eq)) were weighed and added to the reaction system. A solvent (e.g., toluene, ethanol, water (2:1:1)) and a catalyst (e.g., tetrakis(triphenylphosphine)palladium (0.05-0.08 eq)) were added. The mixture was refluxed at 90-110°C for 20-24 hours under a protective gas (e.g., nitrogen). After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M-1.

[0025] Under a protective gas (e.g., nitrogen) system, weigh intermediate M-1 (1 eq), reactant 3 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-5 eq)) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water (2:1:1)) and catalyst (e.g., tetrakis(triphenylphosphine)palladium (0.05-0.08 eq)). Reflux at 90-110℃ for 20-24 h under a protective gas (e.g., nitrogen). After the reaction is complete, cool to 25℃, add purified water, stir, and allow to stand for separation. After separation, purify by column chromatography to obtain intermediate M-2.

[0026] Under a protective gas (e.g., nitrogen) system, weigh intermediate M-2 (1 eq), reactant 4 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-5 eq)) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water (2:1:1)) and catalyst (e.g., tetrakis(triphenylphosphine)palladium (0.05-0.08 eq)). Reflux at 90-100°C for 20-24 h under a protective gas (e.g., nitrogen). After the reaction is complete, cool to 25°C, add purified water, stir, and allow to stand for separation. After separation, purify by column chromatography to obtain intermediate M.

[0027] Synthesize the compound shown in Formula I using the following synthetic route: The specific process is as follows: Under a protective gas (e.g., nitrogen) system, reactant A (1 eq), organoboron (e.g., pinacol diborate (1-1.2 eq)), basic substance (e.g., potassium acetate (2.5-3 eq)), catalyst (e.g., tris(dibenzylacetone)palladium (0.01-0.03 eq)), organophosphorus co-catalyst (e.g., X-phos (0.08-0.24 eq)), and solvent (e.g., 1,4-dioxane)) are added to a three-necked flask. The mixture is heated to 90-100°C and refluxed for 20-24 hours. After the reaction is complete, purified water and dichloromethane are added, the mixture is stirred, allowed to stand for separation, and purified by column chromatography after separation to obtain intermediate I-1 as shown.

[0028] Under a protective gas (e.g., nitrogen) system, weigh out Formula I-1 (1 eq), intermediate M (1-1.2 eq), basic substance (e.g., potassium acetate (2.5-3 eq)), catalyst (e.g., tris(dibenzylacetone)palladium (0.01-0.03 eq)), organophosphorus co-catalyst (X-phos (0.08-0.24 eq)), and solvent (e.g., 1,4-dioxane). Heat to 90-100 °C and reflux for 20-24 hours. After the reaction is complete, add purified water and dichloromethane, stir, allow to stand for separation, separate the layers, and purify by column chromatography to obtain compound I as shown.

[0029] Thirdly, embodiments of the present invention provide a dual-body material, comprising a first body material and a second body material, wherein the mass ratio of the first body material to the second body material is (1:99)-(99:1), the first body material is selected from the compounds having the structural formula shown in Formula I, and the second body material is selected from the compounds shown in Formula II below: D1, D2, and D3 are each independently selected from any one of substituted or unsubstituted C6-C42 aryl groups or substituted or unsubstituted C6-C30 heteroaryl groups; in particular, deuterated C6-C42 aryl groups may be selected. L4, L5, and L6 are each independently selected from the linking bond or substituted or unsubstituted C6-C18 aryl groups.

[0030] Furthermore, D1 and D2 are selected from substituted or unsubstituted C6-C18 aryl groups; D3 is selected from substituted or unsubstituted C6-C36 aryl groups and substituted or unsubstituted C6-C30 heteroaryl groups.

[0031] Furthermore, D1 is selected from any one of substituted or unsubstituted phenyl, biphenyl, and terphenyl; D2 is selected from any one of substituted or unsubstituted phenyl, naphthyl, biphenyl, terphenyl, and benzo[a]phenanthryl; D3 is selected from any one of substituted or unsubstituted phenyl, naphthyl, and biphenyl. L4, L5, and L6 are each independently selected from the linking bond, phenyl, or naphthyl.

[0032] It should be noted that (1) the above "substituted or unsubstituted" means that the group can be unsubstituted or substituted by one or more substituents. The "substitution" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent, and there is no restriction on the position of substitution, as long as the position is where the hydrogen atom is substituted, that is, the position where the substituent can be substituted, and when two or more substituents are substituted, the two or more substituents can be the same or different from each other.

[0033] (2) The substituted group in “substituted or unsubstituted” is selected from deuterium, fluorine, C1-C10 alkyl, deuterated C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocyclic alkyl, and deuterated C3-C10 heterocyclic alkyl, and its heteroatom is selected from oxygen, nitrogen, and sulfur. (3) The heteroaryl group includes a monocyclic aromatic group and a polycyclic aromatic ring system with at least one heteroatom, and the heteroatom includes, but is not limited to, O, S, N and P.

[0034] Furthermore, the second host material is selected from any one of the compounds shown in the following structural formulas: .

[0035] This invention employs a combination of a first host compound with a specific structure and a second host compound with a specific structure. In the first host material, isosilazole is fused with an aryl group to form a rigid planar large π-conjugated structure, effectively enhancing electron transport capability. Furthermore, the rigid fused ring structure provides a high glass transition temperature and thermal decomposition temperature, which is beneficial for maintaining a stable amorphous thin film state during device fabrication and long-term operation, preventing crystallization, and extending device lifespan. The triarylamine structure is linked to form an intramolecular "donor-acceptor" structure, effectively regulating the HOMO and LUMO energy levels of the molecule. The covalent connection between the two gives the molecule bipolar transport characteristics. Simultaneously, the second host compound, containing triazine, allows triplet excitons to be dispersed on both hosts, reducing triplet-triplet annihilation (TTA). When applied to organic electroluminescent devices, this effectively reduces the driving voltage while improving the device's luminous efficiency and lifespan.

[0036] Furthermore, embodiments of the present invention also provide a method for preparing a second host material, comprising: synthesizing according to the following synthetic route: The specific process is as follows: Under a protective gas (e.g., nitrogen) system, reactant 1 (1 eq), reactant 2 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-4 eq)) were weighed and added to the reaction system. A solvent (e.g., toluene, ethanol, water) and a catalyst tetra(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90°C for 24 h under a protective gas (e.g., nitrogen) system, then cooled to 25°C, filtered, and subjected to solid column chromatography to obtain compound H-1 as shown.

[0037] Under a protective gas (e.g., nitrogen) system, weigh H-1 (1 eq), reactant 2-1 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-4 eq)) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water) and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq). Reflux at 90-100 °C for 24 h under a protective gas (e.g., nitrogen), then cool to 25 °C, filter, and perform solid column chromatography to obtain compound H-2 as shown.

[0038] Under a protective gas (e.g., nitrogen) system, weigh H-2 (1 eq), reactant 2-2 (1-1.2 eq), and carbonate (e.g., potassium carbonate (3-4 eq)) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water) and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq). Reflux at 90-100 °C for 24 h under nitrogen protection, then cool to 25 °C, filter, and perform solid column chromatography to obtain compound H (the compound shown in Formula II).

[0039] Fourthly, embodiments of the present invention provide an organic electroluminescent device, comprising a first electrode, a second electrode, and an organic electroluminescent material layer disposed between the first electrode and the second electrode; wherein the organic electroluminescent material layer comprises a light-emitting layer; the raw materials for forming the light-emitting layer comprise a doping material and the aforementioned dual host material; wherein the mass ratio of the dual host material to the doping material is (1~99):(99~1).

[0040] More specifically, the organic electroluminescent device includes an anode, a hole transport region, an emissive layer, an electron transport region, and a cathode. The raw materials forming the emissive layer include a first host material of Formula I and a second host material of Formula II.

[0041] As an anode material, a material with a high work function is generally preferred to facilitate hole injection into the organic material layer. The anode materials that can be used for the first electrode of the organic electroluminescent device of the present invention include: metals, such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides, such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides, such as ZnO:Al or SnO2:Sb; conductive polymers, such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxo)thiophene] (PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

[0042] As a cathode material, materials with a small work function are generally preferred to facilitate electron injection into the organic material layer. The cathode materials that can be used for the second electrode of the organic electroluminescent device of the present invention include: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; multilayer materials, such as LiF / Al or LiO2 / Al; and so on, but are not limited thereto.

[0043] The hole injection layer material is a material that receives holes from the anode at low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer. Hole injection materials include metalloporphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile hexaazabenzophenanthrene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinones, and conductive polymers based on polyaniline and polythiophene, etc.

[0044] Hole transport layer materials are materials that can receive holes from the anode or hole injection layer and transport the holes to the light-emitting layer, and have high hole mobility; and hole transport layer materials include, but are not limited to, arylamine-based organic materials, conductive polymers, block copolymers that have both conjugated and non-conjugated parts.

[0045] An electron blocking layer can be disposed between the hole transport layer and the light-emitting layer. Materials known in the art, such as arylamine-based organic materials, can be used as the electron blocking layer.

[0046] The main material of the light-emitting layer is selected from the dual-main material provided in the embodiments of the present invention.

[0047] The hole blocking layer can be disposed between the electron transport layer and the light-emitting layer, and can be made of materials known in the art, such as triazine-based compounds.

[0048] The electron transport layer facilitates electron transport. Electron transport materials are those that advantageously receive electrons from the cathode and transport them to the light-emitting layer, exhibiting high electron mobility. These include, but are not limited to, Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic free radical compounds; hydroxyflavonoid-metal complexes, etc. The thickness of the electron transport layer can range from 1 nm to 50 nm. Electron transport layers with a thickness of 1 nm or greater have the advantage of preventing a decrease in electron transport properties, while thicknesses of 50 nm or less have the advantage of preventing an increase in driving voltage caused by an excessively thick electron transport layer.

[0049] The electron injection layer can promote electron injection, and the electron injection material preferably has the ability to transport electrons, exhibiting an electron injection effect from the cathode, and demonstrating excellent electron injection effect on the light-emitting layer or light-emitting material. It prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and also possesses excellent thin film forming ability. Specific examples include fluorenones, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, azoles, diazoles, triazoles, imidazoles, perylenetetracarboxylic acid, fluorenemethane, anthrones, and their derivatives, metal complexes, nitrogen-containing five-membered ring derivatives, etc., but are not limited to these.

[0050] Depending on the materials used, the above-mentioned organic electroluminescent devices can be top-emitting, bottom-emitting, or bilaterally emitting.

[0051] The organic electroluminescent device described in this invention can be used in organic solar cells, electronic paper, organic photoreceptors, or organic thin-film transistors.

[0052] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0053] Example 1 This invention provides a method for preparing a host material (compound R011), comprising: S1, Synthetic intermediate M;

[0054] Under nitrogen protection, reactant 1 (CAS: 10025-85-1 1eq), reactant 2 (CAS: 5720-05-8 1eq), and potassium carbonate (3eq) were weighed and added to the reaction system. Toluene, ethanol, water (2:1:1) and catalyst tetrakis(triphenylphosphine)palladium (0.05eq) were added. The mixture was refluxed at 90°C for 24 hours under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M-1.

[0055] Under nitrogen protection, intermediate M-1 (1 eq), reactant 3 (CAS: 881913-20-8 1 eq), and potassium carbonate (3 eq) were weighed and added to the reaction system. Toluene, ethanol, water (2:1:1) and catalyst tetra(triphenylphosphine)palladium (0.05 eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M-2.

[0056] Under nitrogen protection, intermediate M-2 (1 eq), reactant 4 (CAS: 2451355-72-71 eq), and potassium carbonate (3 eq) were weighed and added to the reaction system. Toluene, ethanol, water (2:1:1) and catalyst tetra(triphenylphosphine)palladium (0.05 eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M.

[0057] S2, Synthetic compound R011;

[0058] Under nitrogen protection, reactant A (CAS: 1435-50-3 1 eq), magnesium (1 eq), and tetrahydrofuran were added to a three-necked flask and stirred for 1 hour. The reaction solution was cooled to 0°C, and a tetrahydrofuran solution of reactant B (CAS: 75-78-5 1 eq) was slowly added dropwise. The reaction solution was brought back to room temperature and stirred for 3 hours. The solid was filtered off under nitrogen, and the filtrate was concentrated under reduced pressure. Purification by column chromatography yielded intermediate R011-1 (yield: 55.6%).

[0059]

[0060] Under nitrogen protection, intermediate R011-1 (1eq) and THF were added to a three-necked flask. Add n-butyllithium (0.016 eq) dropwise at 40°C. Transfer the reaction mixture to... The mixture was stirred at 40°C for 20 minutes, and then a THF solution of reactant C (CAS: 107650-21-5 1eq) was added dropwise. The resulting mixture was heated to room temperature, quenched with saturated NH4Cl, extracted with ethyl acetate, dried and concentrated to give intermediate R011-2 (yield: 67.5%).

[0061]

[0062] Under nitrogen protection, K₂CO₃ (1 eq), CuI (0.1 eq), and total nitrogen were added to a three-necked flask. 6 amino β Cyclodextrin (0.04 eq) and DMSO were added. Then, a DMSO solution of intermediate formula R011-2 (0.5 eq) was added. The mixture was stirred at 110 °C for 24 hours. After the reaction was complete, water was added to the reaction mixture. The mixture was then extracted and concentrated by drying to give intermediate formula R011-3 (yield: 73.2%).

[0063]

[0064] Under nitrogen protection, intermediate R011-3 (1 eq), reactant D (CAS: 24388-23-6 1.2 eq), potassium acetate (3 eq), tris(dibenzylacetone)dipalladium (0.03 eq), X-phos (0.24 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 110 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate R011-4 (yield: 75.3%).

[0065]

[0066] Under nitrogen protection, intermediate formula R011-4 (1 eq), pinacol diborate (1.2 eq), potassium acetate (3 eq), tris(dibenzylacetone)palladium (0.03 eq), X-phos (0.24 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 110 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate formula R011-5 (yield: 72.3%).

[0067]

[0068] Under nitrogen protection, intermediate R011-5 (1 eq), intermediate M (1 eq), potassium acetate (2.5-3 eq), tris(dibenzylacetone)palladium (0.01 eq), X-phos (0.08 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 90 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain compound R011.

[0069] The characterization data of this compound are as follows: Analytical value: 671.52; Yield: 64.7%; HPLC > 99%; Elemental analysis: C, 86.89; H, 5.75; N, 4.28; Si, 4.08. Its NMR spectrum is shown below. Figure 1 .

[0070] Example 2 This embodiment provides a method for preparing the second host material (compound H020), including:

[0071] Under nitrogen protection, reactant 1 (CAS: 108-77-0 1eq), reactant 2 (CAS: 98-80-61.2eq), and potassium carbonate (4eq) were weighed and added to the reaction system. Toluene, ethanol, water, and tetrakis(triphenylphosphine)palladium catalyst (0.08eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection, then cooled to 25°C, filtered, and subjected to solid column chromatography to obtain compound H020-1 (yield 66.7%).

[0072]

[0073] Under nitrogen protection, H020-1 (1 eq), reactant 2-1 (CAS: 98-80-6 1 eq), and potassium carbonate (4 eq) were weighed and added to the reaction system. Toluene, ethanol, water, and tetrakis(triphenylphosphine)palladium catalyst (0.08 eq) were added. The mixture was refluxed at 90 °C for 24 h under nitrogen protection, then cooled to 25 °C, filtered, and subjected to solid column chromatography to obtain compound H020-2 (yield 68.2%).

[0074]

[0075] Under nitrogen protection, 1 eq of H020-2, reactant 2-2 (CAS: 128388-54-51 eq), and 4 eq of potassium carbonate were weighed and added to the reaction system. Toluene, ethanol, water, and 0.08 eq of tetra(triphenylphosphine)palladium catalyst were added. The mixture was refluxed at 90 °C for 24 h under nitrogen protection, then cooled to 25 °C, filtered, and subjected to solid column chromatography to obtain the compound H020 shown. The characterization data of this compound are as follows: Measured value: 462.38; Yield: 77%; HPLC > 99%; Elemental analysis: C, 86.69; H, 5.12; N, 9.19.

[0076] It should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of Examples 1 and 2 listed above, so they will not be described in detail here.

[0077] Device Examples This device example provides a method for fabricating an organic electroluminescent device, including: (1) The ITO (indium tin oxide) glass substrate with a thickness of 1500 Å was washed twice with distilled water and ultrasonically washed for 30 min. Then it was washed twice with distilled water and ultrasonically washed for 10 min. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 min each time), dried, and then transferred to a plasma cleaner for 5 min to obtain the ITO anode.

[0078] (2) In the vapor deposition machine, HIL is vacuum vapor deposited on the ITO anode surface obtained in step (1) with a thickness of 200 Å to obtain a hole injection layer.

[0079] (3) A hole transport layer is obtained by vacuum evaporation of HTL on the surface of the hole injection layer obtained in step (2) with a thickness of 400 Å.

[0080] (4) A light-emitting layer material is deposited on the surface of the hole transport layer by evaporation. A linear gradient co-evaporation method is used to obtain a thickness of 300 Å. The material of the light-emitting layer includes a dual host material and a doped material. The mass ratio of the first host compound and the second host compound is 60:40, and the mass ratio of the dual host material and the doped material is 10:1. The dual host materials are the host materials provided in Comparative Examples 1-18 and Device Examples 1-30, respectively.

[0081] (5) A hole blocking layer is formed by vapor deposition of BAlq on the surface of the light-emitting layer obtained in step (4) with a thickness of 100 Å.

[0082] (6) Vacuum vapor deposition of ETL on the surface of the hole blocking layer obtained in step (5) with a thickness of 400 Å is obtained to obtain the electron transport layer.

[0083] (7) Vacuum vapor deposition of EIL with a thickness of 15 Å is performed on the surface of the electron transport layer obtained in step (6); an electron injection layer is obtained.

[0084] (8) 1500 Å of Al is deposited on the surface of the electron injection layer obtained in step (7) to form a cathode, thereby obtaining the organic electroluminescent device.

[0085] The structure of the material used in the above preparation method is as follows:

[0086] The structural formula of the main material of the light-emitting layer used in the comparative example is shown below:

[0087] Performance testing: The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Comparative Examples 1-18 and Device Examples 1-30 were characterized at a brightness of 5000 nits. The test results are shown in Table 1 below.

[0088] Table 1 Performance test results of organic electroluminescent devices

[0089] As shown in Table 1, the driving voltage of the organic electroluminescent devices of Device Examples 2-30 of the present invention is 3.71-3.94V, which is significantly lower than that of Comparative Examples 1-18. At the same time, the luminous efficiency is higher than that of Comparative Examples 1-18, and the lifetime is significantly improved compared with Comparative Examples 1-18.

[0090] Because the isosilazolium fused with the aryl group in the organic electroluminescent compound provided in this invention, combined with the triazine group as a strong electron acceptor, energy level regulation is achieved, the TADF effect is induced, electron transport capability is provided, and thermal stability is enhanced, thereby improving the service life of the material.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A main material, characterized in that, It is selected from the compounds shown in Formula I below: In this context, either X1 or Y1 is CR3, and the other is Si(R1)(R2); R1, R2, and R3 each independently represent any one of substituted or unsubstituted C1-C10 alkyl groups or substituted or unsubstituted C6-C12 aryl groups. Ring A is a substituted or unsubstituted C6-C14 aryl group; L1, L2 and L3 are each independently selected from any one of the following: linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C6-C30 heteroarylene and substituted or unsubstituted C10-C30 fused ring group; R4 and R5 are each independently selected from any one of hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted tetraphenylsilyl, and substituted or unsubstituted C10-C30 fused ring group.

2. The main material according to claim 1, characterized in that, R4 and R5 are each independently selected from any one of hydrogen, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted tetraphenylsilyl, and substituted or unsubstituted C10-C20 fused ring group.

3. The main material according to claim 1 or 2, characterized in that, R4 and R5 are each any one of the groups shown in the following structural formulas: 。 4. The main material according to claim 1, characterized in that, L1, L2, and L3 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 arylene, a substituted or unsubstituted C6-C24 heteroarylene, or a substituted or unsubstituted C10-C20 fused ring group; Preferably, all hydrogen atoms in the compound shown in Formula I can be independently replaced by deuterium.

5. The main material according to claim 1, characterized in that, It is selected from any one of the compounds shown in the following structural formulas: 。 6. A dual-body material, characterized in that, It includes a second host material and a first host material, wherein the first host material is selected from the host material of claim 1, and the second host material is selected from the compound shown in Formula II below: D1, D2 and D3 are each independently selected from any one of substituted or unsubstituted C6-C42 aryl and substituted or unsubstituted C6-C30 heteroaryl; L4, L5, and L6 are each independently selected from the linking bond, substituted or unsubstituted C6-C18 aryl groups.

7. The dual-body material according to claim 6, characterized in that, D1 and D2 are selected from substituted or unsubstituted C6-C18 aryl groups; D3 is selected from substituted or unsubstituted C6-C42 aryl groups and substituted or unsubstituted C6-C30 heteroaryl groups; Preferably, D1 is selected from any one of substituted or unsubstituted phenyl, biphenyl, and terphenyl; D2 is selected from any one of substituted or unsubstituted phenyl, naphthyl, biphenyl, terphenyl and benzophenanthryl; D3 is selected from any one of substituted or unsubstituted phenyl, naphthyl, or biphenyl; Preferably, L4, L5, and L6 are each independently selected from the linking bond, phenyl, or naphthyl group; Preferably, the mass ratio of the first main material to the second main material is (1:99)-(99:1).

8. The dual-body material according to claim 6, characterized in that, The second host material is selected from any one of the compounds shown in the following structural formulas: 。 9. A method for preparing the main material according to claim 1, characterized in that, Perform the synthesis according to the following synthesis path: ； Preferably, intermediate M is synthesized according to the following synthetic pathway: 。 10. An organic electroluminescent device, characterized in that, It includes a light-emitting layer formed from the dual-body material as described in claim 6.

Images