Host material, organic electroluminescent material, preparation method therefor, and organic electroluminescent device

Abstract

The present application relates to the technical field of organic electroluminescent material, in particular to a host material, an organic electroluminescent material, a preparation method thereof and an organic electroluminescent device. The host material is selected from the compound shown in the following general formula I: wherein L0, L1 and L2 are independently selected from any one of a bond, a substituted or unsubstituted C6-C30 aryl and a substituted or unsubstituted C3-C30 heteroaryl, R1 and R2 are each independently selected from any one of a substituted or unsubstituted C1-C10 alkyl, a substituted or unsubstituted C3-C10 cycloalkyl, a substituted or unsubstituted phosphine oxide, a substituted or unsubstituted silane, a substituted or unsubstituted C6-C42 aryl and a substituted or unsubstituted C3-C42 heteroaryl. When the host material is applied to the organic electroluminescent device, the driving voltage of the device can be reduced, the luminous efficiency can be improved and the service life can be prolonged.

Description

Technical Field

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

[0002] Organic light-emitting diode (OLED) technology is an electroluminescent technology that uses organic materials as the light-emitting layer. This technology offers advantages such as low driving voltage, high brightness, high efficiency, and the ability to achieve large-area flat-panel color displays. The principle of OLED is based on the fact that when a voltage is applied to the organic material, electrons and holes are injected from the cathode and anode into the organic layer, respectively, and recombine to form excitons. These excitons release energy during relaxation, generating photons, thus emitting light. In recent years, significant progress has been made in OLED technology research, including improving device efficiency, lifetime, and brightness, reducing costs, and achieving a wider color gamut. These advancements make OLED technology a promising candidate for applications in the display and lighting fields.

[0003] Organic light-emitting diode (OLED) efficiency generally refers to the device's ability to convert electrical energy into light energy, and is mainly divided into internal quantum efficiency and external quantum efficiency. Internal quantum efficiency refers to the recombination efficiency of excitons in the light-emitting layer, while external quantum efficiency refers to the ratio of the number of photons extracted from the device to the number of electrons injected into the device.

[0004] Currently, the main technical challenges of organic electroluminescent devices include the following aspects: (1) Efficiency: The luminous efficiency of organic electroluminescent devices is relatively low and needs further improvement. (2) Lifespan: The stability and durability of organic materials are poor, resulting in a short lifespan for the devices. (3) Color stability: The color of organic materials is easily affected by environmental factors such as temperature and humidity, leading to color instability. (4) Manufacturing process: The manufacturing process of organic electroluminescent devices is relatively complex and needs further optimization. (5) Cost: The high cost of organic materials and manufacturing processes limits the large-scale application of organic electroluminescent devices.

[0005] The use of a dual-host system in organic electroluminescent materials offers several advantages: Different host materials exhibit varying electron and hole transport capabilities. A dual-host system, through proper matching, can achieve a more balanced transport of electrons and holes in the emitting layer, improving exciton formation efficiency and reducing exciton quenching, thereby enhancing the device's luminous efficiency and performance. Furthermore, the dual hosts can effectively transfer excited-state energy to the emitting guest through energy transfer processes, broadening the energy transfer channels and contributing to improved energy transfer efficiency, thus enhancing the luminescent effect. Finally, the dual-host system can disperse stress, reducing the formation of crystal defects and aggregated states, thereby improving the stability and lifetime of organic electroluminescent devices and slowing down device aging and degradation.

[0006] Therefore, how to develop a long-life, low-driving-voltage organic electroluminescent material with dual host, its preparation method, and organic electroluminescent device are technical problems that urgently need to be solved by those skilled in the art.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a host material, an organic electroluminescent material, a method for preparing the same, and an organic electroluminescent device. When the host material provided in the embodiments of this invention is applied to an organic electroluminescent device, it can reduce the device's driving voltage, improve luminous efficiency, and extend its lifespan.

[0009] This invention is implemented as follows: In a first aspect, the present invention provides a host material selected from compounds of the following general formula:

[0010] L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; wherein the heteroatom is selected from any one or more of oxygen, nitrogen, and sulfur. R1 and R2 are each independently selected from any one of substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

[0011] In a second aspect, the present invention provides an organic electroluminescent material, comprising a first host material and a second host material, wherein the first host material is the host material described in the foregoing embodiments, and the second host material is selected from compounds represented by the following general formula II:

[0012] L3, L4 and L5 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, a substituted or unsubstituted C6-C30 aromatic amino group and a substituted or unsubstituted C3-C30 heteroaryl amino group, wherein the heteroatom is selected from one or more of oxygen, nitrogen and sulfur. T1, T2, and T3 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted germanyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

[0013] Thirdly, the present invention provides a method for preparing the organic electroluminescent material described in the foregoing embodiments, wherein a first host material and a second host material are mixed, and the first host material and the second host material are synthesized respectively according to the following synthesis route: ; .

[0014] Fourthly, the present invention provides an organic electroluminescent device comprising a light-emitting layer formed of the organic electroluminescent material described in the foregoing embodiments.

[0015] The present invention has the following beneficial effects: the host material provided in the embodiments of the present invention contains a benzo[a]anthracene structure in its core, and thus the host material has the following advantages: 1) Hole blocking and exciton confinement: Due to its electron-rich properties, the benzene anthracene group has a deep HOMO energy level, which can effectively block holes in the luminescent layer and confine the carrier recombination region to the luminescent layer, thus effectively improving the luminescence efficiency.

[0016] 2) Carrier balance: The benzene anthracene group can form a balanced bipolar carrier transport channel, so that the mobility of holes and electrons reaches the same order of magnitude, maximizing the radiative recombination efficiency.

[0017] 3) Precise control of emission color: By connecting triazine groups modified with different aryl or heterocyclic groups at position 1, the HOMO / LUMO energy levels can be precisely controlled, thereby improving the color purity of the material.

[0018] The host material provided in this embodiment of the invention contains a triazine structure in its core, thereby giving the host material the following advantages: 1) Improved stability and electronic tolerance: The triazine structure gives the compound good stability and electronic tolerance, ensuring the material's performance is stable in the working environment and reducing performance degradation caused by external factors and electronic shocks.

[0019] 2) Enhanced electron injection and transport capabilities: Triazine structure has strong electron-withdrawing properties, which can lower the electron injection energy barrier, making it easier for electrons to be injected into organic materials, while increasing the electron migration speed in the material and improving electron transport efficiency.

[0020] 3) Reduced driving voltage: Triazine structure materials applied to organic electroluminescent devices can significantly reduce device driving voltage, reduce energy consumption, and improve energy utilization efficiency.

[0021] 4) Improve luminescence performance: Triazine compounds have good luminescence performance and can be used to prepare organic electroluminescent devices. They can improve the current efficiency of the devices and enable the devices to achieve higher brightness with lower current.

[0022] 5) Extend device lifespan: Triazine-based materials can improve device stability and efficiency, reduce device damage and aging during operation, and effectively extend device lifespan.

[0023] 6) Improved thermal stability: Compounds with triazine structure as the core and aryl and other groups forming side chains have good thermal stability, which can ensure that the device works stably under different temperature environments.

[0024] 7) Improved film-forming properties: Some triazine compounds have improved molecular planarity through design, which enhances the film-forming properties of the material, reduces problems in the production process, and facilitates large-scale production and preparation of high-quality thin-film devices.

[0025] The second host material provided in this embodiment of the invention contains a triarylamine structure in its core, which gives it the following advantages: 1) Improve hole transport performance: Triarylamines have low ionization potential of amine units, good electron donation, and high hole mobility.

[0026] 2) Improve luminous efficiency: As a hole transport layer material, the triarylamine structure can effectively reduce the total reflection loss and waveguide loss of traditional OLED devices and improve light extraction efficiency.

[0027] 3) Extended service life: Compounds with triarylamine structure have good physical and thermal stability and are not easy to crystallize and aggregate between molecules.

[0028] 4) Energy level matching advantage: The introduction of triarylamine structure can adjust the HOMO / LUMO energy levels of the material, making it more compatible with the energy levels of other materials.

[0029] 5) Reduce driving voltage: This helps to improve and balance the transport of charge carriers in the device and reduce the voltage of the device.

[0030] In summary, the organic electroluminescent material containing dual host materials provided by this invention, when used in organic electroluminescent devices, can reduce the driving voltage of the organic electroluminescent devices while improving the efficiency and lifespan of the devices. Attached Figure Description

[0031] 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.

[0032] Figure 1 The NMR spectrum of the main material provided in Embodiment 1 of the present invention. Detailed Implementation

[0033] 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.

[0034] In a first aspect, embodiments of the present invention provide a host material selected from compounds represented by the following general formula:

[0035] L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; wherein the heteroatom is selected from any one or more of oxygen, nitrogen, and sulfur. R1 and R2 are each independently selected from any one of substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

[0036] Further, in a preferred embodiment of the present invention, L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 aryl group, and a substituted or unsubstituted C3-C12 heteroaryl group, wherein the heteroatom is selected from one or more of oxygen, nitrogen, and sulfur. For example, L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 aryl group, and a substituted or unsubstituted C3-C12 heteroaryl group, wherein the heteroatom is selected from one or more of oxygen, nitrogen, and sulfur.

[0037] Further, in a preferred embodiment of the invention, R1 and R2 are each independently selected from any one of substituted or unsubstituted phosphooxy groups, substituted or unsubstituted silyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C3-C30 heteroaryl groups, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium. For example, R1 and R2 are each independently selected from one or two or more combinations of the following substituted or unsubstituted groups: In this context, any substituted site among the substituents can be a connection site.

[0038] It should be noted that: (1) “Substituted or unsubstituted” in the embodiments of the present invention means that the group may not be substituted, or may be substituted by one or more substituents. The “substitution” means that the hydrogen atom bonded to the carbon atom of the group 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 may be the same as or different from each other.

[0039] (2) The substituent in “substituted or unsubstituted” is selected from any one of deuterium, fluorine, cyano, C1-C10 alkyl group substituted or unsubstituted with deuterium, C3-C20 cycloalkyl group substituted or unsubstituted with deuterium and C3-C20 heterocycloalkyl group substituted or unsubstituted with deuterium, wherein the heteroatom is selected from one or more of oxygen, nitrogen and sulfur.

[0040] (3) The hydrogen in the compounds of the general formula I can be independently replaced by deuterium or not replaced by deuterium.

[0041] Furthermore, in the embodiments of the present invention, the main material is selected from any one of the compounds shown in the following structural formulas:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] Where D represents deuterium.

[0060] In a second aspect, embodiments of the present invention provide an organic electroluminescent material containing two host materials, comprising a first host material and a second host material, wherein the first host material is selected from the host materials described above, and the second host material is selected from compounds represented by the following general formula II:

[0061] L3, L4 and L5 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, a substituted or unsubstituted C6-C30 aromatic amino group and a substituted or unsubstituted C3-C30 heteroaryl amino group, wherein the heteroatom is selected from one or more of oxygen, nitrogen and sulfur. T1, T2, and T3 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted germanyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

[0062] Furthermore, in a preferred embodiment of the present invention, L3, L4 and L5 are each independently selected from any one of a linking bond, a substituted or unsubstituted C6-C18 aryl group, a substituted or unsubstituted C3-C12 heteroaryl group, a substituted or unsubstituted C6-C18 aromatic amino group and a substituted or unsubstituted C3-C18 heteroaryl amino group, wherein the heteroatom is selected from any one or more of oxygen, nitrogen and sulfur; And / or, T1, T2 and T3 are each independently selected from any one of substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted germanyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom is selected from any one or more of oxygen, nitrogen and sulfur.

[0063] In an optional embodiment, the second host material is selected from any one of the following compounds:

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] Where D represents deuterium.

[0071] Thirdly, the present invention provides a method for preparing the organic electroluminescent material described in the foregoing embodiments, wherein a first host material and a second host material are mixed, and the first host material is synthesized according to the following synthesis route:

[0072] The specific process is as follows: (1) Under the protection of an inert gas (e.g., nitrogen), reactant 1 (1 eq), reactant 2 (1 eq), and basic substance (e.g., potassium carbonate) (2-3 eq) were weighed and placed into the reaction system. Solvent (e.g., toluene, ethanol, water) and catalyst (e.g., tetra(triphenylphosphine)palladium) (0.01-0.05 eq) were added. The reaction was carried out at 40-50°C for 24 h under the protection of an inert gas (e.g., nitrogen). After the reaction was completed, the mixture was cooled to 25°C and treated to obtain the compound HT-1 shown.

[0073] (2) Under the protection of an inert gas (e.g., nitrogen), weigh compound HT-1 (1 eq), reactant 3 (1 eq), and alkaline substance (e.g., potassium carbonate) (2-3 eq) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water) and catalyst (e.g., tetra(triphenylphosphine)palladium) (0.01-0.05 eq). React at 40-50°C for 24 h under the protection of an inert gas (e.g., nitrogen). After the reaction is completed, cool to 25°C and treat to obtain compound HT-2 as shown.

[0074] (3) Under the protection of an inert gas (e.g., nitrogen), reactant 3 (1 eq), reactant 4 (1 eq), and alkaline substance (e.g., potassium carbonate) (2-3 eq) were weighed and placed into the reaction system. Solvent (e.g., toluene, ethanol, water) and catalyst (e.g., tetra(triphenylphosphine)palladium) (0.01-0.05 eq) were added. The reaction was carried out at 40-50°C for 24 h under the protection of an inert gas (e.g., nitrogen). After the reaction was completed, the mixture was cooled to 25°C and treated to obtain the compound HT-3 shown.

[0075] (4) Under the protection of an inert gas (e.g. nitrogen), weigh compound HT-3 (1 eq) and put it into the reaction system, add dry diethyl ether, cool down to -78°C, add 2.6 M n-butyllithium (2 eq) dropwise, stir at -78°C for 30 min, heat to 0°C and stir for 30 min, add dry DMF, stir for 12 h, after the reaction is completed, add water to quench, and after treatment, obtain compound HT-4 as shown; (5) Under the protection of an inert gas (e.g. nitrogen), weigh HT-4 (1 eq), (methoxymethyl)triphenylphosphine chloride (1.8 eq) and put it into the reaction system. Add THF, cool to -5~-10℃, and dropwise add potassium tert-butoxide (1.8 eq) solution dissolved in THF while maintaining the temperature. After the addition is complete, react for 20 min, slowly raise to room temperature, and react for 1 h. After the reaction is completed, treat to obtain the compound HT-5 shown. (6) Under the protection of an inert gas (e.g. nitrogen), weigh HT-5 (1 eq) and put it into the reaction system, add hexafluoroisopropanol, cool down to -5~-10℃, slowly add trifluoromethanesulfonic acid (3 eq), after the addition is complete, react for 20 min, slowly raise to room temperature, react for 1 h, after the reaction is completed, treat to obtain the compound HT-6 shown. (7) Under the protection of an inert gas (e.g., nitrogen), weigh compound HT-2 (1 eq), compound HT-6 (1 eq), and basic substance (e.g., potassium carbonate) (2-3 eq) and add them to the reaction system. Add solvent (e.g., toluene, ethanol, water) and catalyst (e.g., tetra(triphenylphosphine)palladium) (0.01-0.05 eq). React at 70-90°C for 24 h under the protection of an inert gas (e.g., nitrogen). After the reaction is completed, cool to 25°C and treat to obtain the compound shown in general formula 1.

[0076] Further, the second host material is synthesized according to the following synthetic route:

[0077] The specific process is as follows: (1) Under the protection of an inert gas (e.g. nitrogen), reactant 1 (1 eq), reactant 2 (1 eq), sodium tert-butoxide (2-3 eq) were weighed and placed into the reaction system. Dry toluene, catalyst tris(dibenzylacetone) dipalladium (0.01-0.02 eq) and 50% tritert-butylphosphine (0.022-0.044 eq) were added. The mixture was refluxed at 40-50°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C and treated to obtain the compound H2-T-1 shown.

[0078] (2) Under the protection of an inert gas (e.g., nitrogen), weigh compound H2-T-1 (1 eq), reactant 3 (1 eq), sodium tert-butoxide (2-3 eq) and add them to the reaction system. Add dry toluene, catalyst tris(dibenzylacetone) dipalladium (0.01-0.02 eq) and 50% tritert-butylphosphine (0.022-0.044 eq). Reflux at 110-120°C for 24 h under nitrogen protection. After the reaction is completed, cool to 25°C and treat to obtain the compound shown in general formula II.

[0079] Thirdly, embodiments of the present invention provide an organic electroluminescent device, which includes a first electrode, a second electrode, and an organic electroluminescent material layer disposed between the first electrode and the second electrode; and the organic electroluminescent material layer includes a light-emitting layer; the material forming the light-emitting layer includes a doped material and an organic electroluminescent material containing a dual host material as described above.

[0080] In the organic electroluminescent material containing dual host materials, the mass ratio of the first host material, the second host material, and the dopant material is (1~99):(1~99):(99~1), preferably (1~20):(1~20):(9~1), and more preferably 10:10:1.

[0081] More specifically, an organic electroluminescent device includes an anode, a hole transport region, an emissive layer, an electron transport region, and a cathode. The host material forming the emissive layer includes a first host material shown in Formula 1 and a second host material shown in Formula 2.

[0082] 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.

[0083] 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.

[0084] The hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, and a hole blocking layer, with the light-emitting layer located between the electron blocking layer and the hole blocking layer.

[0085] The material forming the hole injection layer 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.

[0086] 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.

[0087] 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.

[0088] The main material forming the light-emitting layer is selected from compounds with structures shown in general formulas one and two provided in the embodiments of the present invention.

[0089] 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.

[0090] The electron transport layer can promote electron transport. Electron transport materials are materials with high electron mobility that can effectively receive electrons from the cathode and transport them to the light-emitting layer.

[0091] The materials of the electron transport layer include, but are not limited to, Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic free radical compounds; hydroxyflavonoid-metal complexes, etc.

[0092] Preferably, the thickness of the electron transport layer can be from 1 nm to 50 nm. An electron transport layer with a thickness of 1 nm or more has the advantage of preventing a decrease in electron transport characteristics, and an electron transport layer with a thickness of 50 nm or less has the advantage of preventing an increase in driving voltage caused by an excessively thick electron transport layer.

[0093] The electron injection layer can promote electron injection, and the electron injection material preferably has the ability to transport electrons, has the electron injection effect from the cathode, has an excellent electron injection effect on the light-emitting layer or light-emitting material, prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and has excellent thin film forming ability.

[0094] Materials forming the electron injection layer can be, for example, fluorenone, anthraquinone dimethane, biphenylquinone, thiam dioxide, azole, diazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenemethane, anthrone and their derivatives, metal complexes, nitrogen-containing five-membered ring derivatives, etc., but are not limited to these.

[0095] Depending on the materials used, the above-mentioned organic electroluminescent devices can be top-emitting, bottom-emitting, or bilaterally emitting.

[0096] Furthermore, the organic electroluminescent device described in this invention can be used in organic solar cells, electronic paper, organic photoreceptors, or organic thin-film transistors.

[0097] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0098] Example 1 This invention provides a method for preparing the main material (H001), comprising: synthesizing it according to the following synthetic route: ; (1) Under nitrogen protection, reactant 1 (1 eq) (CAS: 269410-07-3), reactant 2 (1 eq) (CAS: 102153-44-6), potassium carbonate (2.5 eq) (CAS: 584-08-7) were weighed and added to the reaction system. Toluene, ethanol, water and catalyst tetra(triphenylphosphine)palladium (0.01 eq) (CAS: 14221-01-3) were added. The reaction was carried out at 40°C for 24 h under nitrogen protection. Heating was stopped after the reactants were completely reacted. The mixture was cooled to 25°C, extracted with water, and the organic phase was collected. The organic phase was dried with anhydrous magnesium sulfate and evaporated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography using dichloromethane / hexane as the eluent to obtain compound H001-1, with a yield of 58.4%.

[0099] (2) Under nitrogen protection, compound H001-1 (1 eq) was weighed and added to the reaction system. Dry diethyl ether was added, the temperature was lowered to -78℃, and 2.6M n-butyllithium (2 eq) was added dropwise. The mixture was stirred at -78℃ for 30 min, then heated to 0℃ and stirred for 30 min. Dry DMF was added and stirred for 12 h. After the reaction was completed, water was added to quench the reaction, and ethyl acetate was added to extract the mixture. The organic phase was collected and dried with anhydrous magnesium sulfate. The crude product was obtained by rotary evaporation under reduced pressure. The crude product was purified by silica gel column chromatography using dichloromethane / hexane as the eluent to obtain compound H001-2 as shown, with a yield of 70.6%.

[0100] (3) Under nitrogen protection, compound H001-2 (1 eq), (methoxymethyl)triphenylphosphine chloride (1.8 eq) (CAS: 4009-98-7) was weighed and added to the reaction system. THF was added, and the temperature was lowered to -10℃. While maintaining the temperature, potassium tert-butoxide (1.8 eq) solution dissolved in THF was added dropwise. After the addition was complete, the reaction was allowed to proceed for 20 min. The temperature was then slowly raised to room temperature and the reaction was allowed to proceed for 1 h. After the reaction was completed, water was added to quench the reaction, and ethyl acetate was added to extract the reaction. The organic phase was collected, and anhydrous magnesium sulfate was added to dry the organic phase. The crude product was obtained by rotary evaporation under reduced pressure. The crude product was purified by silica gel column chromatography using dichloromethane / hexane as the eluent to obtain compound H001-3 as shown, with a yield of 62.8%.

[0101] (4) Under nitrogen protection, weigh compound H001-3 (1 eq) and add it to the reaction system. Add hexafluoroisopropanol, cool to -10℃, and slowly add trifluoromethanesulfonic acid (3 eq) (CAS: 1493-13-6). After the addition is complete, react for 20 min, slowly raise to room temperature, and react for 1 h. After the reaction is complete, quench with water, extract with ethyl acetate, collect the organic phase, dry the organic phase with anhydrous magnesium sulfate, and evaporate under reduced pressure to obtain the crude product. Use dichloromethane / hexane as eluent to purify the crude product by silica gel column chromatography to obtain compound H001-4 as shown, with a yield of 57.3%.

[0102] (5) Under nitrogen protection, weigh out the reaction compound H001-4 (1 eq), reactant 3 (1 eq) (CAS: 1883265-32-4), potassium carbonate (2.5 eq) (CAS: 584-08-7) and add them to the reaction system. Add toluene, ethanol, water and catalyst tetra(triphenylphosphine)palladium (0.01 eq) (CAS: 14221-01-3). React at 70°C for 24 h under nitrogen protection. Stop heating after the reactants have reacted completely. Cool to 25°C, add water to extract and separate the liquid. Collect the organic phase. Add anhydrous magnesium sulfate to the organic phase and dry it. Rotary evaporate under reduced pressure to obtain the crude product. Use dichloromethane / hexane as eluent to purify the crude product by silica gel column chromatography to obtain the compound H001 shown.

[0103] The characterization data of compound H001 are as follows: HPLC: 99.93%; molecular weight: 550.34.

[0104] Elemental analysis results: C: 85.03; H: 4.35; N: 7.72; O: 3.03; Yield: 58.75%.

[0105] The proton NMR spectrum is as follows Figure 1 As shown.

[0106] Example 2 This embodiment provides a method for preparing a second host material, including: Perform the synthesis according to the following synthesis path:

[0107] Under nitrogen protection, reactant 1 (1 eq, CAS: 2085325-19-3), reactant 2 (1 eq, CAS: 1427556-45-3), sodium tert-butoxide (2.5 eq) (CAS: 865-48-5) were weighed and added to the reaction system. Dry toluene, catalyst tris(dibenzylacetone)dipalladium (0.02 eq) (CAS: 51364-51-3), and 50% tri-tert-butylphosphine (0.044 eq) were added. The mixture was refluxed at 120 °C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25 °C, extracted with water, and the organic phase was collected. The organic phase was dried with anhydrous magnesium sulfate and evaporated under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography using dichloromethane / hexane as the eluent to obtain the compound H2-103 shown.

[0108] The characterization data of compound H2-103 are as follows: HPLC: 99.94%; molecular weight: 628.40.

[0109] Elemental analysis results: C: 85.82; H: 4.52; N: 4.59; O: 5.22; Yield: 72.36%.

[0110] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of the examples listed above, so they will not be listed one by one here.

[0111] Device Example 1 This embodiment provides a method for fabricating an organic electroluminescent device, including: ITO anode: An ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 Å was cleaned twice with distilled water and ultrasonically washed for 30 min. Then it was cleaned twice more 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.

[0112] HIL (Hole Injection Layer): In a vapor deposition machine, 200 Å of 4,4',4''-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) is vacuum-deposited onto an ITO anode to form a hole injection layer.

[0113] HTL (Hole Transport Layer): A hole transport layer is formed by vacuum evaporating NPB (i.e., N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) at 400 Å onto the hole injection layer.

[0114] EML (Emitting Layer): The emitting layer comprises a first host material, a second host material, and a guest dopant. After forming a hole injection layer and a hole transport layer, the emitting layer is formed on the HTL: the first host compound and the second host compound are introduced as hosts into two chambers of a vacuum vapor deposition apparatus, and compound Z1 is introduced as a dopant into another chamber; the two host materials are evaporated at a 1:1 ratio, and the dopant material is evaporated simultaneously at different rates, and a doping amount of 3wt% based on the total amount of host and dopant is deposited to form an emitting layer with a thickness of 40nm on the hole transport layer.

[0115] HBL (Hole Blocking Layer): A hole blocking layer is formed by vacuum evaporation of bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq) at 100 Åm on the luminescent layer.

[0116] ETL (Electron Transport Layer): 400 Å of 8-hydroxyquinoline aluminum (Alq3) is vacuum-deposited onto the hole-blocking layer to form the electron transport layer.

[0117] EIL (Electron Injection Layer): LiF 210Å is vacuum-deposited on the electron transport layer to form the electron injection layer.

[0118] Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s, with a deposition rate ratio of 1:9, to form a cathode, thus obtaining an organic electroluminescent device.

[0119] Referring to the organic electroluminescent device and its preparation method provided in Device Example 1, another 50 organic electroluminescent compounds were selected to replace the first host compound and the second host compound for the vapor deposition of the host material, and organic electroluminescent devices of the corresponding compounds were prepared.

[0120] The following are the materials used to manufacture the above-mentioned devices: , , .

[0121] The device fabrication processes of Device Examples 1-50, Comparative Examples 1-10, and Parallel Examples 1-5 are completely identical, and the same substrate and electrode materials are used. The film thickness of the electrode materials is also kept consistent. The difference lies in that the two host materials are different, and the corresponding first host compound and second host compound in Table 1 are selected respectively. The specific parameters are shown in Table 1. The structure of the host material used in the comparative examples is as follows:

[0122] Table 1 Raw materials for forming organic electroluminescent devices

[0123] Performance testing: The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Comparative Examples 1-10, Parallel Examples 1-5, and Device Examples 1-50 were characterized at a brightness of 7000 nits. The test results are shown in Table 2 below.

[0124] Table 2 Test Results

[0125] As shown in Table 2, the driving voltage of the single-substrate organic electroluminescent device provided in Parallel Examples 4-5 of the present invention is 3.69V~3.73V, which is 6.97%~10.02% lower than that of Comparative Examples 9-10. At the same time, the luminous efficiency is 5.06%~14.47% higher than that of Comparative Examples 9-10, and the lifetime is 2.53%~3.08% higher than that of Comparative Examples 9-10. The driving voltage of the dual-substrate organic electroluminescent device provided in Device Examples 1-50 and Parallel Examples 1-3 is 2.97V~3.43V, which is 4.05%~20.39% lower than that of Comparative Examples 1-8. At the same time, the luminous efficiency is 3.12%~34.44% higher than that of Comparative Examples 1-8, and the lifetime is 1.21%~7.23% higher than that of Comparative Examples 1-8.

[0126] Therefore, it can be seen that the organic electroluminescent device prepared by the organic electroluminescent compound provided by the present invention as the light-emitting layer material has a significantly lower driving voltage and a significantly improved luminous efficiency and lifetime compared with the organic electroluminescent device prepared by the comparative compounds E-1, E-2, E-3, E-4, E-5, E-6, E-7, E-8, and F-1 as the dual host materials of the light-emitting layer.

[0127] This is because the benzo[a]anthracene structure possesses advantages such as high luminous efficiency and energy utilization, excellent thermal stability and thin film morphology, balanced carrier transport and energy level matching, and flexible molecular modifiability. Moreover, compared to triazine linkages at other positions in benzo[a]anthracene, the position 1 scheme has unique advantages: 1) Reduced steric hindrance and isomers: These two positions are oriented towards both ends of the molecular long axis and are less affected by surrounding steric hindrance, allowing the triazine group and the benzo[a]anthracene core to maintain better coplanarity, thus enhancing intramolecular charge transfer. Simultaneously, it significantly reduces the types of positional isomers, simplifying the synthesis and purification steps. 2) Optimized molecular stacking: Specific linkages facilitate the formation of continuous electron transport channels and suitable intermolecular stacking patterns, effectively suppressing the "efficiency roll-off" problem under high current density, ensuring good stability of the device even at high brightness. Meanwhile, the triazine structure has good stability, which can increase device lifespan. It also has strong electron accepting ability, which can reduce the energy required for electron injection and lower the voltage required for device operation. The triarylamine structure has good film-forming properties, which can improve device performance and stability. It also has strong electron donating ability, which can improve electron transport efficiency.

[0128] 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 compounds represented by the following general formula: L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; wherein the heteroatom is selected from any one or more of oxygen, nitrogen, and sulfur. R1 and R2 are each independently selected from any one of substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

2. The main material according to claim 1, characterized in that, L0, L1, and L2 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 aryl group, and a substituted or unsubstituted C3-C12 heteroaryl group, wherein the heteroatom is selected from one or more of oxygen, nitrogen, and sulfur. And / or, R1 and R2 are each independently selected from any one of substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon and selenium.

3. The main material according to claim 1, characterized in that, L0, L1 and L2 are each independently selected from any one of the following: a linking bond, substituted or unsubstituted benzene, substituted or unsubstituted naphthalene, substituted or unsubstituted biphenyl, substituted or unsubstituted anthracene, substituted or unsubstituted phenanthrene, substituted or unsubstituted dibenzofuran, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted fluorene and substituted or unsubstituted carbazole. And / or, R1 and R2 are each independently selected from one or more combinations of two or more of the following substituted or unsubstituted groups: 。 4. The main material according to any one of claims 1-3, characterized in that, The substituents in the substituted or unsubstituted form are selected from any one of deuterium, fluorine, cyano, C1-C10 alkyl groups substituted or unsubstituted with deuterium, C3-C20 cycloalkyl groups substituted or unsubstituted with deuterium, and C3-C20 heterocycloalkyl groups substituted or unsubstituted with deuterium, wherein the heteroatom is selected from one or more of oxygen, nitrogen, and sulfur; And / or, the hydrogen atoms in the compounds represented by Formula 1 may be independently substituted with or not substituted with deuterium.

5. The main material according to any one of claims 1-3, characterized in that, The host material is selected from any one of the compounds shown in the following structural formulas: Where D represents deuterium.

6. An organic electroluminescent material, characterized in that, It includes a first host material and a second host material, wherein the first host material is the host material as described in claim 1, and the second host material is selected from compounds represented by the following general formula II: L3, L4 and L5 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, a substituted or unsubstituted C6-C30 aromatic amino group and a substituted or unsubstituted C3-C30 heteroaryl amino group, wherein the heteroatom is selected from one or more of oxygen, nitrogen and sulfur. T1, T2, and T3 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted germanyl, substituted or unsubstituted C6-C42 aryl, and substituted or unsubstituted C3-C42 heteroaryl, wherein the heteroatom is selected from one or more of oxygen, nitrogen, sulfur, silicon, and selenium.

7. The organic electroluminescent material according to claim 6, characterized in that, L3, L4, and L5 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted C6-C18 aryl group, a substituted or unsubstituted C3-C12 heteroaryl group, a substituted or unsubstituted C6-C18 aromatic amino group, and a substituted or unsubstituted C3-C18 heteroaryl amino group, wherein the heteroatom is selected from any one or more of oxygen, nitrogen, and sulfur. And / or, T1, T2 and T3 are each independently selected from any one of substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted germanyl, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom is selected from any one or more of oxygen, nitrogen and sulfur.

8. The organic electroluminescent material according to claim 6, characterized in that, The second host material is selected from any one of the following compounds: Where D represents deuterium.

9. A method for preparing the organic electroluminescent material according to claim 6, characterized in that, The first host material and the second host material are mixed, wherein the first host material and the second host material are synthesized respectively according to the following synthesis path: ； 。 10. An organic electroluminescent device, characterized in that, It includes a light-emitting layer formed from the organic electroluminescent material as described in claim 6.

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