Organic electroluminescent material, preparation method and application thereof, and organic electroluminescent device

Abstract

The invention discloses an organic electroluminescent material, a preparation method and application thereof and an organic electroluminescent device, and relates to the technical field of organic electroluminescent materials. The organic electroluminescent material has a structure as shown in a formula I in the specification, dibenzofuran is taken as a center, a group Ar2 is substituted at the 5-8 positions of the dibenzofuran, arylamine side chains are substituted at the 1 position of the dibenzofuran, one of the arylamine side chains is ortho-substituted 9-phenylcarbazole, the other side chain is Ar1 selected from specific groups, and the compound as shown in the formula I is obtained. When the compound is applied to an organic electroluminescent device, the technical effects of reducing the driving voltage, prolonging the service life and improving the luminous efficiency are achieved.

Description

An organic electroluminescent material, its preparation method and application, and an organic electroluminescent device. Technical Field

[0001] This invention relates to the field of organic electroluminescent materials technology, and more specifically, to an organic electroluminescent material, its preparation method and application, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs), with their advantages such as self-illumination and high contrast, have been widely used in smartphones, automotive displays, and other fields, becoming a core direction for display technology upgrades. Among them, blue organic electroluminescent devices are key to full-color displays and white light illumination. Their performance directly determines the color, power consumption, and lifespan of OLED products, making them one of the key research and development directions.

[0003] OLED devices consist of an anode, a cathode, and an intermediate organic functional layer (including a hole injection / transport layer, an emissive layer, and an electron transport / injection layer). The emissive auxiliary layer (second hole transport layer) is a key structure for optimizing device performance. It promotes hole transport, lowers the energy level barrier, and blocks electrons to limit exciton nonradiative recombination, thereby reducing the driving voltage and improving luminous efficiency and lifetime. It is particularly important for the high-energy exciton utilization efficiency and stability of blue light devices.

[0004] However, there is a lack of high-performance materials for existing light-emitting auxiliary layers, and this problem is even more pronounced in blue light devices: blue light exciton energy requires materials that possess high triplet energy levels, strong exciton blocking ability, and high structural stability to avoid exciton quenching and material degradation. Furthermore, OLED performance is affected by multiple factors, including the physicochemical properties of materials, vapor deposition morphology, and charge transport balance. The interactions of these factors are even more complex in blue light devices, making the development of high-performance materials extremely challenging.

[0005] As panel manufacturers continue to raise their product performance requirements, the number of existing materials available for constructing light-emitting auxiliary layers and imparting excellent performance to devices is very limited.

[0006] Therefore, how to develop a novel organic electroluminescent material with low driving voltage, high luminous efficiency, high triplet energy level and long lifetime, as well as its preparation method and application, and organic electroluminescent devices are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides an organic electroluminescent material, its preparation method and application, and an organic electroluminescent device. The present invention centers on dibenzofuran, substituting an Ar2 group at positions 5-8 of the dibenzofuran and substituting an aromatic amine side chain at position 1. One of the aromatic amine side chains is an ortho-substituted 9-phenylcarbazole, and the other side chain is an Ar1 selected from specific groups, resulting in compound formula I of the present invention. When applied to organic electroluminescent devices, this invention achieves the technical effects of reducing driving voltage, extending lifetime, and improving luminous efficiency.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] One object of the present invention is to provide an organic electroluminescent material having the structure shown in Formula I:

[0010] Wherein, Ar1 is selected from deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, deuterated or unsubstituted biphenyl, deuterated or unsubstituted terphenyl, and deuterated or unsubstituted phenylnaphthyl; Ar2 is selected from deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, and deuterated or unsubstituted biphenyl; L1 is selected from deuterated or unsubstituted linking bond, deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, and deuterated or unsubstituted biphenyl; q is selected from 0, 1, 2, 3, or 4.

[0011] Preferably, formula I includes the structure of formulas a-f:

[0012] Where n is selected from 1, 2, 3, 4 or 5; m is selected from 1, 2, 3, 4, 5, 6, 7, 8 or 9; p is selected from 1, 2, 3, 4, 5, 6, 7 or 8.

[0013] Preferably, Formula I is selected from any of the following compounds:

[0014]

[0015] .

[0016] The second objective of this invention is to provide a method for preparing the organic electroluminescent material as described above, comprising the following steps: (1) under a nitrogen atmosphere, dissolving reactant aI in toluene, dissolving reactant bI in toluene, adding tris(dibenzylacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyloxide to the solution, heating to 90℃-110℃, reacting for 8-12 h, and purifying by column chromatography to obtain intermediate cI; (2) under a nitrogen atmosphere, dissolving intermediate cI in toluene, dissolving reactant dI in toluene and slowly adding it to the intermediate cI solution, adding tris(dibenzylacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyloxide to the solution, heating to 90℃-110℃, reacting for 8-12 h, and purifying by column chromatography to obtain the organic electroluminescent material shown in formula I; the synthetic route of the organic electroluminescent material shown in formula I is as follows:

[0017] Furthermore, in step (1), the molar ratio of reactant aI, reactant bI, tris(dibenzylacetone)palladium, tritert-butylphosphine and sodium tert-butyloxide is 1:(1.1-1.3):(0.01-0.05):(0.02-0.1):(2-3).

[0018] Furthermore, in step (2), the molar ratio of intermediate cI, reactant dI, tris(dibenzylideneacetone)palladium, tritert-butylphosphine and tert-butyloxide sodium is (1.0):(1.1-1.3):(0.01-0.05):(0.02-0.1):(2-3).

[0019] The series of palladium-catalyzed coupling reactions in this invention utilize the activity differences of halogens I>Br>Cl, and control the reaction sites by controlling the reaction conditions. The reactions are purified by column chromatography or silica gel funnel to remove byproducts and obtain the target compound.

[0020] For raw materials that are not publicly available, those skilled in the art can synthesize them using classic Suzuki coupling reactions, Buchwald–Hartwig coupling reactions, butyllithium reactions, and apply them to this invention.

[0021] The following is a reference to common knowledge: "Organic Chemistry of Transition Metals" (6th Edition), Robert H. Crabtree, published by East China University of Science and Technology Press, Shanghai, September 00, 2017, ISBN: 978-7-5628-5111-0, page 388.

[0022] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0023] A third objective of this invention is to provide an application of the described organic electroluminescent material in the fabrication of organic electroluminescent devices.

[0024] A fourth objective of this invention is to provide an organic electroluminescent device, comprising a first electrode, a second electrode, and an organic functional layer disposed between the first electrode and the second electrode; the organic functional layer includes a light-emitting auxiliary layer; the light-emitting auxiliary layer includes the organic electroluminescent material.

[0025] Furthermore, the organic functional layer includes one or more of the following structures as organic functional layers: hole injection layer, hole transport layer, electron blocking layer, light emission auxiliary layer, light emission layer, hole blocking layer, electron transport layer, electron injection layer, and capping layer.

[0026] Furthermore, an organic functional layer is formed using vacuum evaporation or solution coating, wherein the solution coating method includes spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, or roll coating.

[0027] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: The present invention takes dibenzofuran as the center, replaces a group Ar2 at the 5-8 position of dibenzofuran, and replaces an aromatic amine side chain at the 1 position. One of the aromatic amine side chains is an ortho-substituted 9-phenylcarbazole, and the other side chain is Ar1 selected from specific groups. The resulting compound of the present invention, Formula I, when applied in organic electroluminescent devices, achieves the technical effects of reducing driving voltage, long lifetime, and improving luminous efficiency.

[0028] This invention places the Ar2 substituent on the opposite side of the aromatic amine side chain, which has little effect on conjugation and mainly plays a role in regulating the spatial configuration of the material. This is beneficial to increasing the glass transition temperature of the material, improving the molecular orientation and packing density during vacuum evaporation, enhancing the orderliness of intermolecular π-π interactions, and thus improving carrier mobility.

[0029] The ortho-substitution of 9-phenylcarbazole in the side chain of aromatic amines can reduce the conjugated area, enhance the triplet energy level, and improve the exciton blocking ability. At the same time, the substitution of the aromatic amine at the 1-position of dibenzofuran in this invention can avoid the formation of intramolecular hydrogen bonds, retain an appropriate degree of molecular torsional freedom, and effectively regulate the triplet energy level and carrier transport balance while maintaining the integrity of the conjugated system. Its comprehensive performance is superior to that of other substitution sites. Attached Figure Description

[0030] Figure 1 shows the 1H NMR spectrum of compound 1 from Example 1. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and related drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] The specific embodiments described below are merely some embodiments of this application, and not all embodiments. It should be noted that the values ​​given in the following embodiments are as accurate as possible; however, those skilled in the art will understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximation, not an absolutely accurate value.

[0033] The features and performance of the present invention will be further described in detail below with reference to specific embodiments.

[0034] Example 1: Synthesis of Compound 1

[0035] Reactant a-2: 1821235-55-5; Reactant b-2: 92-67-1; Reactant d-2: 2243975-95-1; Under nitrogen atmosphere, reactant a-2 (1.0 eq) was dissolved in toluene, and reactant b-2 (1.2 eq) was dissolved in toluene. Tris(dibenzylacetone)dipalladium (0.02 eq), tri-tert-butylphosphine (0.02 eq), and sodium tert-butyloxide (2.5 eq) were added. The mixture was heated to 90 °C and reacted for 12 h. The mixture was purified by column chromatography to obtain intermediate c-2 (yield: 88.6%). Under atmospheric conditions, intermediate c-2 (1.0 eq) was dissolved in toluene, and reactant d-2 (1.2 eq) was dissolved in toluene and slowly added to the intermediate c-2 solution. Tris(dibenzylideneacetone)dipalladium (0.02 eq), tri-tert-butylphosphine (0.02 eq) and sodium tert-butyloxide (2.5 eq) were added to the solution. The temperature was raised to 90 °C and the reaction was carried out for 10 h. The solution was purified by column chromatography to obtain chemical formula 2 (yield: 82.2%, test value MS(ESI, m / Z): [M+H]+= 728.30).

[0036] The proton NMR spectrum of compound 1 is shown in Figure 1.

[0037] HPLC purity: >99.9%.

[0038] Elemental analysis: Theoretical values: C, 88.98; H, 4.98; N, 3.84; O, 2.19; Measured values: C, 88.73; H, 5.13; N, 3.98; O, 2.21. It should also be noted that other compounds in this application can be obtained by referring to the synthesis methods listed in the embodiments above, and therefore will not be listed individually here. The mass spectrometer used in this application is a Waters XEVO TQD, a low-precision mass spectrometer with an ESI source.

[0039] Organic electroluminescent devices have a structure comprising one or more of the following organic layers: a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a capping layer. The structure of organic light-emitting elements is not limited to this and may include fewer or more organic layers.

[0040] The compound of Formula I prepared in this invention is used as a light-emitting auxiliary layer material.

[0041] Regarding the compound shown in Formula I, when manufacturing organic light-emitting elements, an organic layer is formed using vacuum evaporation or solution coating. Solution coating methods include, but are not limited to, spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, and roll coating.

[0042] The organic light-emitting elements of this invention are classified into top-emitting, bottom-emitting, or bidirectional-emitting types based on the materials used. These organic light-emitting elements are used in organic light-emitting devices, including but not limited to flat panel displays, computer monitors, medical monitors, televisions, billboards, lamps for internal or external lighting and / or signals, head-up displays, fully transparent or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, photo albums, personal digital assistants (PDAs), wearable devices, laptops, digital cameras, camcorders, viewfinders, microdisplays, 3D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screens, phototherapy devices, and signs.

[0043] As the anode material, a material with a high work function is selected to facilitate the injection of holes into the organic layer. Specific examples of anode materials that can be used in this invention include vanadium, chromium, copper, zinc, gold or their alloys; 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; and conductive polymers such as polypyrrole and polyaniline.

[0044] The hole injection layer is selected as a p-doped hole injection layer, which means a hole injection layer doped with p-doped agents. P-doped agents are materials that can impart p-type semiconductor characteristics. P-type semiconductor characteristics refer to the ability to inject or transport holes at the HOMO energy level, i.e., the material characteristics of high hole conductivity.

[0045] Hole transport materials are materials capable of receiving holes from the anode or hole injection layer and transporting them to the light-emitting layer, and possessing high hole mobility. Hole transport materials are selected from aryl amine derivatives, conductive polymers, and block copolymers containing both conjugated and non-conjugated portions.

[0046] An auxiliary light-emitting layer (multilayer hole transport layer) is added between the hole transport layer and the light-emitting layer. The auxiliary light-emitting layer primarily assists the hole transport layer and is therefore sometimes referred to as a second hole transport layer. This layer allows holes transferred from the anode to smoothly move to the light-emitting layer and blocks electrons transferred from the cathode, confining them within the light-emitting layer. This reduces the potential barrier between the hole transport layer and the light-emitting layer, lowers the driving voltage of the organic light-emitting device, and further increases hole utilization, thereby improving the device's luminous efficiency and lifetime.

[0047] The luminescent material in the luminescent layer is a material that can receive holes and electrons from the hole transport layer and the electron transport layer respectively, and combine them to emit light in the visible light region. The material with high quantum efficiency for fluorescence or phosphorescence is selected.

[0048] The light-emitting layer consists of a host material and a dopant material.

[0049] The mass ratio of the main material to the dopant material is 90-99.5:0.5-10.

[0050] The main materials include aromatic fused-ring derivatives or heterocyclic compounds. Specifically, the aromatic fused-ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentane derivatives, phenanthrene compounds, or fluoranthene compounds, and the heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, or pyrimidine derivatives.

[0051] The dopant materials of this invention include fluorescent doping and phosphorescent doping, specifically including aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, or metal complexes.

[0052] The electron transport layer facilitates electron transport. Electron transport materials are materials that receive electrons from the cathode and transport them to the light-emitting layer; materials with high electron mobility are selected. The electron transport layer includes an electron buffer layer, a hole blocking layer, and the electron transport layer itself.

[0053] The electron injection layer facilitates electron injection, possesses electron transport capabilities, and prevents excitons generated in the luminescent layer from migrating to the hole injection layer. Materials for the electron injection layer include, but are not limited to, oxazoles, oxadiazoles, triazoles, imidazoles, perylenetetracarboxylic acids, fluorenemethane, anthrones and their derivatives, magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, ytterbium, or their alloys, metal complexes, or nitrogen-containing 5-membered ring derivatives.

[0054] The cathode is selected from materials with a low work function to facilitate electron injection into the organic material layer, which has a thickness between 0.5 and 5 nm. To enable easy electron injection into the organic layer, the cathode material is selected from materials with a low work function, specifically including magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead or their alloys: LiF / Al or LiO2 / Al, Mg / Ag multilayer structures.

[0055] Apart from Formula I included in the light-emitting auxiliary layer disclosed in this invention, there are no special restrictions on the materials of other layers in OLED devices. Existing hole injection materials, hole transport materials, hole transport auxiliary materials, dopant materials, hole blocking layer materials, electron transport layer materials, and electron injection materials can be used.

[0056] The organic electroluminescent composition and organic electroluminescent device provided by the present invention will be specifically described below with reference to specific application examples.

[0057] Application Example 1: Fabrication of Organic Electroluminescent Devices: a. ITO Anode: An ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) glass substrate with a coating thickness of 150 nm was cleaned twice with distilled water and ultrasonically washed for 30 min. It was then repeatedly cleaned twice with distilled water and ultrasonically washed for 10 min. After cleaning, it was baked in a vacuum oven at 220℃ for 2 hours. After baking, it was cooled before use. Using this substrate as the anode, the device was deposited using a vapor deposition machine, and other functional layers were sequentially deposited on it.

[0058] b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s. The chemical formulas of HT and P-dopant are shown below. The deposition rate ratio of HT to P-dopant is 95:5, and the thickness is 10 nm. c. HTL (Hole Transport Layer): HT of 135 nm is vacuum-deposited on the hole injection layer as a hole transport layer at a deposition rate of 1.5 Å / s. d. Prime (Light Emitting Assist Layer): Compound 2 of the present invention of 5 nm is vacuum-deposited on the hole transport layer as a light emitting assist layer at a deposition rate of 0.5 Å / s. e. EML (Light Emitting Layer): Then, on the above-mentioned light emitting assist layer, a host material and a dopant material of 25 nm thickness are vacuum-deposited at a deposition rate of 1 Å / s as a light emitting layer. The chemical formulas of the host and dopant are shown below. The deposition rate ratio of the host to the dopant is 98:2.

[0059] f. HB (hole blocking layer): HB with a thickness of 5.0 nm is vacuum-deposited at a deposition rate of 0.5 Å / s as a hole blocking layer.

[0060] g. ETL (Electron Transport Layer): ET and Liq with a thickness of 30 nm are vacuum-deposited at a deposition rate of 1 Å / s as the electron transport layer; the deposition rate ratio of ET to Liq is 50:50.

[0061] h. EIL (Electron Injection Layer): A 1.0 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form an electron injection layer.

[0062] i. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s for 13 nm, with a deposition rate ratio of 1:9, to obtain the OLED device.

[0063] j. Optical extraction layer: A CPL with a thickness of 70 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer.

[0064] k. Encapsulate the vapor-deposited substrate: First, use a coating equipment to coat the cleaned cover plate with UV adhesive. Then, move the coated cover plate to the lamination section, place the vapor-deposited substrate on the top of the cover plate, and finally, laminate the substrate and cover plate together under the action of the lamination equipment, while simultaneously curing the UV adhesive by light.

[0065] .

[0066] Application Examples 2-98: Organic electroluminescent devices of Application Examples 2-98 were prepared according to the above-described method for preparing organic electroluminescent devices, except that compound 1 in Application Example 1 was replaced with the corresponding compounds as shown in Table 1 to form a light-emitting auxiliary layer.

[0067] Comparative Examples 1-24: Organic electroluminescent devices were prepared according to the above-described method for preparing organic electroluminescent devices, except that compound 1 in Application Example 1 was replaced with comparative compounds 1-24 corresponding to those in Table 1. The structural formulas of comparative compounds 1-24 are as follows:

[0068]

[0069] The driving voltage, luminous efficiency, BI value, and lifetime of the organic electroluminescent devices obtained by applying Examples 1-98 and Comparative Examples 1-24 to the above devices were characterized at a brightness of 1000 nits. The test results are shown in Table 1 below: Table 1 Test results of luminous characteristics (brightness value is 1000 nits)

[0070] This invention centers on dibenzofuran, substituting an Ar2 group at positions 5-8 and a side chain of an aromatic amine at position 1. One of the aromatic amine side chains is an ortho-substituted 9-phenylcarbazole, and the other side chain is an Ar1 selected from specific groups, resulting in compound formula I. This invention achieves significant improvements in driving voltage, luminous efficiency, and lifetime. As shown in Table 1, the device test results of compound formula I indicate that the driving voltage is between 3.59-3.8V, the luminous efficiency is between 188-200.2 cd / A, and the lifetime is between 480-540 h. In contrast, compounds 1-24 have driving voltages between 3.82-3.92V, luminous efficiencies between 175.0-180 cd / A, and lifetimes between 410-440 h. This demonstrates a significant improvement in device performance. Specifically, compared to compound 1… The difference between comparative compounds 2 and 4 and compounds 2, 21, and 258 of the present invention lies in the different position of the Ar2 substituent on the dibenzofuran in the comparative compounds and compounds 2, 194, 13, 30, 29, and 234 of the present invention. The difference between comparative compounds 7-12 and compounds 2, 194, 13, 30, 29, and 234 of the present invention lies in the absence of Ar2 substitution in the comparative compounds. The substituent on the dibenzofuran in the comparative compounds extends the conjugated area on the same side of the aromatic amine, resulting in a lower triplet energy level and a weaker exciton blocking ability, which is insufficient to block the diffusion of blue light excitons. In the present invention, the Ar2 substituent is placed on the opposite side of the aromatic amine side chain, which has a smaller impact on conjugation and mainly plays a role in regulating the spatial configuration of the material. This is beneficial to increasing the glass transition temperature of the material, improving the molecular orientation and packing density during vacuum evaporation, enhancing the orderliness of intermolecular π-π interactions, and thus improving the carrier mobility.

[0071] The difference between compounds 15 and 16 and compounds 5,258 of this invention lies in the different side chains of the aromatic amine. The ortho-substituted 9-phenylcarbazole can reduce the conjugated area, enhance the triplet energy level, and improve exciton blocking ability. At the same time, the introduction of electron-withdrawing substituents (-CN, -F, etc.) should be avoided, as these groups will cause a significant drop in the triplet energy level through intramolecular charge transfer effects, destroying the exciton confinement function. Other side chain designs should avoid using fluorene-type substituents, as alkane-containing structures cannot withstand exciton impacts in high-energy blue light devices, leading to alkane bond breakage and affecting lifetime. Furthermore, fluorene-type substituents will significantly raise the HOMO energy level, making the structure unable to match the deep HOMO energy level of the blue light host, creating a large energy barrier, increasing voltage, and reducing efficiency and lifetime.

[0072] The difference between compound 21 and compound 261, compound 23, compound 24, and compound 1 of the present invention lies in the substitution position of the amine group at position 1 on dibenzofuran, while in the present invention, the amine group is substituted at position 1 on dibenzofuran. Blue organic light-emitting devices require materials with high triplet energy levels. Theory and experiments have confirmed that amine substituents at positions 1 or 4 of the heterocyclic skeleton can meet this requirement. However, 4-position substitution structures easily form intramolecular hydrogen bonds, restricting molecular torsion and expanding the conjugated plane, thus lowering the triplet energy level. This results in restricted molecular conformational torsion, excessive expansion of the conjugated plane, and a significant decrease in the triplet energy level. In contrast, 1-position substitution avoids the formation of intramolecular hydrogen bonds, retains a moderate degree of freedom in molecular torsion, and effectively regulates the triplet energy level and carrier transport balance while maintaining the integrity of the conjugated system. Its overall performance is superior to other substitution sites.

[0073] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent material, characterized in that, The organic electroluminescent material has the structure shown in Formula I: Wherein, Ar1 is selected from deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, deuterated or unsubstituted biphenyl, deuterated or unsubstituted terphenyl, and deuterated or unsubstituted phenylnaphthyl; Ar2 is selected from deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, and deuterated or unsubstituted biphenyl; L1 is selected from deuterated or unsubstituted linking bond, deuterated or unsubstituted phenyl, deuterated or unsubstituted naphthyl, and deuterated or unsubstituted biphenyl; q is selected from 0, 1, 2, 3, or 4.

2. The organic electroluminescent material according to claim 1, characterized in that, Equation I includes the structures of Equations Ia to If: Where n is selected from 1, 2, 3, 4 or 5; m is selected from 1, 2, 3, 4, 5, 6, 7, 8 or 9; p is selected from 1, 2, 3, 4, 5, 6, 7 or 8.

3. The organic electroluminescent material according to claim 1, characterized in that, Formula I is selected from any of the following compounds: 。 4. A method for preparing the organic electroluminescent material as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Under nitrogen atmosphere, reactant aI was dissolved in toluene, reactant bI was dissolved in toluene, and tris(dibenzylacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyloxide were added to the solution. The temperature was raised to 90℃-110℃ and the reaction was carried out for 8-12 h. The solution was purified by column chromatography to obtain intermediate cI; (2) Under nitrogen atmosphere, intermediate cI was dissolved in toluene, reactant dI was dissolved in toluene and slowly added to the intermediate cI solution. Tris(dibenzylacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyloxide were added to the solution. The temperature was raised to 90℃-110℃ and the reaction was carried out for 8-12 h. The solution was purified by column chromatography to obtain the organic electroluminescent material shown in formula I; The synthetic route of the organic electroluminescent material shown in formula I is as follows: 。 5. The method for preparing the organic electroluminescent material according to claim 4, characterized in that, In step (1), the molar ratio of reactant aI, reactant bI, tris(dibenzylacetone)palladium, tritert-butylphosphine and sodium tert-butyloxide is 1:(1.1-1.3):(0.01-0.05):(0.02-0.1):(2-3).

6. The method for preparing the organic electroluminescent material according to claim 4, characterized in that, In step (2), the molar ratio of intermediate cI, reactant dI, tris(dibenzylacetone)palladium, tritert-butylphosphine and sodium tert-butyloxide is (1.0):(1.1-1.3):(0.01-0.05):(0.02-0.1):(2-3).

7. The use of the organic electroluminescent material as described in any one of claims 1-3 in the fabrication of organic electroluminescent devices.

8. An organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and an organic functional layer disposed between the first electrode and the second electrode; the organic functional layer includes a light-emitting auxiliary layer; the light-emitting auxiliary layer includes the organic electroluminescent material according to any one of claims 1-3.

9. An organic electroluminescent device according to claim 8, characterized in that, The organic functional layer includes one or more of the following structures as organic functional layers: hole injection layer, hole transport layer, electron blocking layer, light-emitting auxiliary layer, light-emitting layer, hole blocking layer, electron transport layer, electron injection layer, and capping layer.

10. An organic electroluminescent device according to claim 8, characterized in that, Organic functional layers are formed by vacuum evaporation or solution coating, wherein the solution coating method includes spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, or roll coating.

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