A compound having a hole blocking function, an organic electroluminescence device containing the same, and application thereof

Abstract

This invention provides a compound with hole-blocking function, an organic electroluminescent device containing the same, and their applications. The compound with hole-blocking function has the structure shown in Formula I. The triazine derivative is linked to naphthalene substituted with dibenzofuran or dibenzothiophene via biphenyl. The resulting compound can be used as a material for the hole-blocking layer, and has the advantages of reducing driving voltage, improving luminous efficiency, and extending service life.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials technology, specifically, it relates to a compound with hole blocking function, an organic electroluminescent device containing the compound, and its applications. Background Technology

[0002] OLED (Organic Light Emitting Diode) technology, leveraging the self-emissive properties of organic thin films under an electric field, has become a highly competitive core area in fields such as flat panel displays, solid-state lighting, and backlight modules. Its unique advantages, including flexibility, high contrast, and low power consumption, are continuously driving technological innovation in related industries. Within the family of organic optoelectronic devices, the performance breakthroughs of OLEDs are inseparable from the innovation of organic materials. By precisely designing the molecular structure of luminescent materials, full-spectrum emission control can be achieved, and the flexible architecture of single or multiple luminescent layers can better meet the spectral requirements of different application scenarios, providing ample space for high-end applications.

[0003] In the multilayer structure of OLED devices, hole blocking materials are key functional layers that determine the device's luminous efficiency, lifetime, and stability. Their core function is to construct a precise control barrier for charge transport, regulating the injection dynamics of electrons from the cathode to the emissive layer while simultaneously blocking the ineffective leakage of holes to the cathode. This ultimately enables efficient recombination of electrons and holes within the emissive layer, thereby maximizing exciton generation efficiency and radiative luminescence efficiency.

[0004] Despite the commercialization and continuous iteration of OLED technology, the field of hole-blocking materials still faces numerous core challenges. The variety of high-performance candidate materials is relatively limited, and existing materials struggle to simultaneously meet the four core requirements of high electron mobility, optimal energy level matching, strong stability, and low cost, exhibiting significant performance bottlenecks. Furthermore, in high-end applications, existing materials do not provide sufficient synergistic improvement in lifetime and luminous efficiency, failing to meet stringent usage requirements. Therefore, developing novel high-performance organic hole-blocking materials with higher electron mobility, superior energy level structure, and enhanced stability has become paramount for promoting the further development and industrialization of OLED technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a compound with hole-blocking functionality, an organic electroluminescent device containing the compound, and its applications. In the compound of the present invention, a triazine derivative reacts with biphenyl... Linking triazine derivatives, which possess high electron mobility, helps improve the hole-blocking ability and promote electron transport in materials, thereby increasing the fluorescence quantum yield, reducing the driving voltage, and enhancing luminescence efficiency. Triazine derivatives also exhibit good rigidity, effectively improving the thermal stability and extending the service life of materials. (The last sentence appears to be incomplete and unrelated to the preceding text. It likely refers to a specific compound or process involving biphenyls.) Linking can extend the conjugated chains, increase the fused ring structure, enhance the degree of intramolecular electron delocalization, improve electron mobility, and simultaneously improve the thermal stability of the material. The resulting compound can be used as a hole-blocking layer material, offering advantages such as reduced driving voltage, improved luminescent efficiency, and extended lifetime.

[0006] To achieve this objective, the present invention adopts the following technical solution: On one hand, the present invention provides a compound with hole-blocking function, the compound having the structure shown in Formula I: , Where L is ★ and * represent permissible linkage sites; ★ is linked to triazine derivatives, and * is linked to naphthyl groups. X is selected independently from O or S; Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, respectively, and their heteroatoms are one or more of O, S, N, Si, Ge, and Se. Furthermore, Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted C6-C18 heteroaryl, respectively, and their heteroatoms are one or more of O, S, N, and Si. In Formula I above, all hydrogen atoms are either substituted with deuterium or not substituted with deuterium.

[0007] Furthermore, the compound with hole-blocking function has a structure shown in any one of formulas I-1 to I-8: .

[0008] Preferably, Ar1 and Ar2 are each independently selected from substituted or unsubstituted groups of the following: in In the radical group, the asterisk represents the linking site. The short lines on the Si atoms in the group represent the bonding sites; the bonding positions of other groups are any substituted positions.

[0009] The terms “substituted or unsubstituted C6-C30 aryl”, “substituted or unsubstituted C6-C18 aryl”, “substituted or unsubstituted C6-C30 heteroaryl”, and “substituted or unsubstituted C6-C18 heteroaryl” refer to the number of carbon atoms in the aryl and heteroaryl groups, which represents the number of carbon atoms constituting the unsubstituted aryl or unsubstituted alkyl group, or the total number of heteroatoms and carbon atoms constituting the heteroaryl group, without considering the number of carbon atoms in the substituents.

[0010] The term "substitution" means substitution by one, two or more substituents selected from the following: hydrogen, deuterium, halogen, cyano, trifluoromethyl, trimethylsilyl, trimethylgermanium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracene, phenanthrene, thiophene, furanyl, pyrrole, benzothiophene, benzofuranyl, pyridyl, indolyl, cyclopentyl, cyclohexyl, adamantane, or substitution by two or more substituents linked together from the substituents listed above.

[0011] In this invention, C6-C30 can be C6, C8, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28 or C30, etc., and C6-C18 can be C6, C7, C8, C9, C10, C11, C12, C13, C14, C16 or C18, etc.

[0012] In one embodiment of the present invention, the compound having hole-blocking function is any one of the following compounds: .

[0013] Secondly, the present invention also provides a method for synthesizing a compound with hole-blocking function. The organic compound described in this invention can be prepared by methods known to those skilled in the art. Alternatively, the following reaction procedure is preferred for preparation, and the specific synthetic route is as follows: Synthesis route: Step 1: Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0-1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V=2:1:1), and Pd(pph3)4 (0.05-0.08 eq) and potassium carbonate (2.5-3.0 eq) were added. The mixture was heated to 90-100℃ and refluxed for 12-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring, the mixture was allowed to stand and separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 1. Step 2: Under nitrogen protection, intermediate 1 (1.0 eq) and starting material C (1.0-1.5 eq) were dissolved in 1,4-dioxane, and Pd2(dba)3 (0.02 eq), X-phos (2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 0.05 eq) and potassium acetate (2.5-3.0 eq) were added. The mixture was heated to 90-100℃ and refluxed for 12-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring, the mixture was allowed to stand and separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 2. Step 3: Under nitrogen protection, intermediate 2 (1.0 eq) and starting material D (1.0-1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V=2:1:1), and Pd(pph3)4 (0.05-0.08 eq) and potassium carbonate (2.5-3.0 eq) were added. The mixture was heated to 90-100℃ and refluxed for 12-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring, the mixture was allowed to stand and separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 3. Step 4: Under nitrogen protection, intermediate 3 (1.0 eq) and starting material C (1.0-1.5 eq) were dissolved in 1,4-dioxane, and Pd2(dba)3 (0.02 eq), X-phos (0.05 eq) and potassium acetate (2.5-3.0 eq) were added. The mixture was heated to 90-100℃ and refluxed for 12-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring, the mixture was allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate 4. Step 5: Under nitrogen protection, intermediate 4 (1.0 eq) and starting material E (1.0-1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V=2:1:1), and Pd(pph3)4 (0.05-0.08 eq) and potassium carbonate (2.5-3.0 eq) were added. The mixture was heated to 90-100 °C and refluxed for 12-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring, the mixture was allowed to stand and separate into layers. After separation, the mixture was purified by column chromatography to obtain the compound shown in Formula I. ; Hal1, Hal2, Hal3, Hal4 and Hal5 are selected from halogens (F, Cl, Br or I), and the other groups are the same as those defined above, and will not be repeated.

[0014] Thirdly, the present invention also provides an organic electroluminescent device, including an anode, a cathode, and an organic layer disposed between the anode and the cathode; the organic layer includes a hole-blocking layer containing a compound with hole-blocking function having the structure shown in Formula I above.

[0015] Preferably, the organic layer further includes one or a combination of at least two of the following: a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a capping layer.

[0016] The structure of the organic electroluminescent device is not limited to this, and may include fewer or more organic layers.

[0017] In one embodiment of the present invention, when manufacturing an organic electroluminescent device, an organic layer is formed by vacuum evaporation or solution coating.

[0018] In one embodiment of the present invention, the solution coating method includes one or more of spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating and roller coating, but is not limited thereto.

[0019] In one embodiment of the present invention, the organic electroluminescent device is classified into top-emitting type, bottom-emitting type or bidirectional-emitting type according to the material used.

[0020] As an anode material, materials with a large work function are usually preferred to facilitate the injection of holes into the organic material layer.

[0021] In one embodiment of the invention, specific examples of anode materials that can be used 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 not limited thereto.

[0022] Hole injection materials are materials that advantageously receive holes from the anode at low voltages, 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.

[0023] In one embodiment of the present invention, the material of the hole injection layer includes metalloporphyrin, oligothiophene, arylamine-based organic materials, hexanitrile hexaazabenzophenanthrene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, and conductive polymers based on polyaniline and polythiophene, but is not limited thereto, and may also include other compounds capable of p-doping.

[0024] The material of the hole transport layer is one that can receive holes from the anode or hole injection layer and transport the holes to the light-emitting layer, and a material with high hole mobility is suitable.

[0025] In one embodiment of the present invention, the material of the hole transport layer includes, but is not limited to, arylamine-based organic materials, conductive polymers, block copolymers having both conjugated and non-conjugated portions.

[0026] The luminescent layer can emit red, green, or blue light and can be formed from phosphorescent or fluorescent materials. The material of the luminescent layer is a material that can emit light in the visible light region by receiving holes and electrons from the hole transport layer and the electron transport layer, respectively, and by combining the holes with the electrons, and is preferably a material that has favorable quantum efficiency for fluorescence or phosphorescence.

[0027] In one embodiment of the present invention, the material of the light-emitting layer includes: 8-hydroxyquinoline aluminum ligand (Alq3); carbazole-based compounds; dipolystyrene-based compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; compounds based on benzocarbazole, benzothiazole, and benzimidazole; polymers based on poly(p-phenylenevinylene) (PPV); spirocyclic compounds; polyfluorene; fluorene, etc., but not limited thereto.

[0028] In one embodiment of the present invention, the light-emitting layer comprises a host material and a dopant material.

[0029] In one embodiment of the present invention, the host material of the light-emitting layer includes fused aromatic ring derivatives, heterocyclic compounds, etc.

[0030] Specifically, the fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentane derivatives, phenanthrene compounds, fluoranthene compounds, etc., and heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, ladder-type furan compounds, pyrimidine derivatives, etc., however, the materials are not limited to these.

[0031] In one embodiment of the present invention, the doping material of the light-emitting layer includes fluorescent doping and phosphorescent doping.

[0032] For example, it can be selected from aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, etc.

[0033] The hole blocking layer blocks holes from the anode at the interface of the device's light-emitting layer, thereby increasing the probability of electron and hole recombination at the interface and increasing the device's luminous efficiency.

[0034] The compound with the structure shown in Formula I in this invention can be used as a material for a hole blocking layer.

[0035] The electron transport layer can facilitate electron transport. The electron transport material is advantageously used to receive electrons from the cathode and transport them to the light-emitting layer; materials with high electron mobility are preferred.

[0036] The electron injection layer can promote electron injection. The preferred electron injection material is a compound that has the ability to transport electrons, has an 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, in addition, has excellent thin film forming ability.

[0037] For example, materials for the electron injection layer include fluorenone, anthraquinone dimethane, biphenylquinone, thiam dioxide, azole, diazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenemethane, anthrone and their derivatives, metal complexes, nitrogen-containing 5-membered ring derivatives, etc., but are not limited to these.

[0038] As a cathode material, materials with a small work function are usually preferred to facilitate the injection of electrons into the organic material layer.

[0039] In one embodiment of the present invention, the cathode material includes: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead, or alloys thereof; multilayer structure materials, such as LiF / Al or LiO2 / Al; and so on, but not limited thereto.

[0040] Fourthly, the present invention also provides applications of organic electroluminescent devices in 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.

[0041] Compared with the prior art, the present invention has the following beneficial effects: Triazine derivatives are linked to naphthalene substituted with dibenzofuran or dibenzothiophene via biphenyl. These triazine derivatives exhibit high electron mobility, which helps improve the hole-blocking ability and promote electron transport, thereby increasing the fluorescence quantum yield, reducing the driving voltage, and enhancing luminescence efficiency. Furthermore, triazine derivatives possess good rigidity, effectively improving the thermal stability and extending the lifespan of the material. Linking triazine derivatives with naphthalene substituted with dibenzofuran or dibenzothiophene via biphenyl can extend the conjugated chain, increase the fused ring structure, enhance the intramolecular electron delocalization, and improve electron mobility, while simultaneously improving the thermal stability of the material. The resulting compounds can be used as hole-blocking layer materials, offering advantages such as reduced driving voltage, improved luminescence efficiency, and extended lifespan. Attached Figure Description

[0042] Figure 1 This is the 1H NMR spectrum of compound 135 in Example 1 of the present invention. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0044] It should be noted that the series of palladium-catalyzed coupling reactions in this invention utilize the difference in reactivity between I and Br (which is greater than that of Cl) and the reaction sites are controlled by adjusting the reaction conditions. Furthermore, the reactions are purified using column chromatography or a silica gel funnel to remove byproducts, yielding the target compound. The following are common knowledge references used in the synthesis of the compounds in this invention: Organometallic Chemistry (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.

[0045] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0046] In addition, the values ​​given in the following embodiments are as accurate as possible, but 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 rather than an absolutely accurate value.

[0047] Example 1 Synthesis of Compound 135 CAS: Reactant A-135: 1000391-24-1 CAS: Reactant B-135: 912824-85-2 CAS: Reactant C-135: 73183-34-3 CAS: Reactant D-135: 154407-17-7 CAS: Reactant E-135: 3842-55-5 Step 1: Under nitrogen protection, raw material A-135 (1.0 eq) and raw material B-135 (1.0-1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V=2:1:1), and Pd(pph3)4 (0.08 eq) and potassium carbonate (2.5 eq) were added. The mixture was heated to 100 °C and refluxed for 24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring and standing, the mixture was allowed to separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 1 (yield: 82.6%). Step 2: Under nitrogen protection, intermediate 1 (1.0 eq) and starting material C-135 (1.5 eq) were dissolved in 1,4-dioxane, and Pd2(dba)3 (0.02 eq), X-phos (0.05 eq), and potassium acetate (2.5 eq) were added. The mixture was heated to 100 °C and refluxed for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring and standing, the mixture was allowed to separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 2 (yield: 83.1%). Step 3: Under nitrogen protection, intermediate 2 (1.0 eq) and starting material D-135 (1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V = 2:1:1). Pd(pph3)4 (0.08 eq) and potassium carbonate (2.5 eq) were added, and the mixture was heated to 100 °C and refluxed for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was complete, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring and standing to separate the layers, the mixture was purified by column chromatography to obtain intermediate 3 (yield: 82.9%). Step 4: Under nitrogen protection, intermediate 3 (1.0 eq) and starting material C-135 (1.5 eq) were dissolved in 1,4-dioxane, and Pd2(dba)3 (0.02 eq), X-phos (0.05 eq), and potassium acetate (2.5 eq) were added. The mixture was heated to 100 °C and refluxed for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring and standing, the mixture was allowed to separate into layers. After separation, the mixture was purified by column chromatography to obtain intermediate 4 (yield: 81.4%). Step 5: Under nitrogen protection, intermediate 4 (1.0 eq) and starting material E-135 (1.2 eq) were dissolved in a mixed solution of toluene, ethanol, and water (V:V:V = 2:1:1). Pd(pph3)4 (0.08 eq) and potassium carbonate (2.5 eq) were added, and the mixture was heated to 100 °C and refluxed for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was complete, the mixture was cooled to room temperature, and purified water and dichloromethane were added. After stirring and standing to separate the layers, the mixture was purified by column chromatography to obtain compound 135. (Yield: 86.1%) Characterization: HPLC purity: >99.8%; Test value ((ESI, m / Z): [M+H]+): 677.39; Elemental analysis: Test values: C, 86.67; H, 4.70; N, 6.32; O, 2.41 The proton NMR spectrum of compound 1 is as follows: Figure 1 As shown.

[0048] Other compounds in this application can be obtained by referring to the synthetic methods listed above, so they will not be listed one by one here. The mass spectrometer was a Waters XEVO TQD, low precision, ESI source for testing.

[0049] In addition, it should be noted that other compounds in this application can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0050] Device Example 1 - Organic Electroluminescent Device Prepared Using Compound 135 as a Hole Blocking Material a. ITO Anode: A 150nm thick ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) glass substrate is cleaned twice with distilled water, ultrasonically washed for 30 minutes, then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it is baked in a vacuum oven at 220℃ for 2 hours. After baking, it is cooled before use. Using this substrate as the anode, a vapor deposition process is performed to deposit other functional layers sequentially on it.

[0051] b. HIL (Hole Injection Layer): Hole injection layer materials HT-1 and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s, wherein the deposition rate ratio of HT-1 to P-dopant is 97:3, and the thickness is 10 nm.

[0052] c. HTL (Hole Transport Layer): HT-1 of 120 nm was vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s as the hole transport layer.

[0053] d. Prime (light-emitting auxiliary layer): Prime-1 of 5 nm was vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a light-emitting auxiliary layer.

[0054] e. EML (Light Emitting Layer): A host material (Host-1) and a dopant material (Dopant-1) with a thickness of 30 nm are vacuum-deposited on the light-emitting auxiliary layer at a deposition rate of 1 Å / s. The deposition rate ratio of Host-1 to Dopant-1 is 98:2.

[0055] f. HB (hole blocking layer): Compound 135 with a thickness of 5.0 nm was vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s as a hole blocking layer.

[0056] g. ETL (Electron Transport Layer): ET-1 and Liq with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s, with the deposition rate ratio of ET-1 to Liq being 50:50.

[0057] h. EIL (Electron Injection Layer): A Yb film with a thickness of 1.0 nm is deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form the electron injection layer.

[0058] i. Cathode: Magnesium and silver with a thickness of 13 nm are deposited on the electron injection layer at a deposition rate of 1 Å / s, with a deposition rate ratio of magnesium to silver of 1:9, to obtain the cathode.

[0059] j. Optical extraction layer: CPL-1 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.

[0060] 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 and place the vapor-deposited substrate on the top of the cover plate; finally, laminate the substrate and cover plate together under the action of the lamination equipment, while simultaneously completing the UV adhesive photocuring.

[0061] The structure of the materials used in the device is as follows: .

[0062] Application Example 2-50 Organic electroluminescent devices of Application Examples 2-50 were prepared according to the above-described method for preparing organic electroluminescent devices, except that compound 135 in Device Example 1 was replaced with compounds 5, 14, 17, 25, 32, 40, 47, 56, 67, 75, 84, 91, 100, 106, 117, 127, 143, 154, 166, 175, 183, 191, 202, 214, 224, 232, 241, 254, 265, 273, 288, 292, 304, 312, 326, 344, 356, 368, 376, 387, 402, 415, 430, 442, 454, 467, 480, 491, and 502 to form a hole blocking layer.

[0063] Comparative Examples 1-8 Organic electroluminescent devices were prepared according to the above-described method, except that compound 1 in Application Example 1 was replaced with comparative compounds a and h, respectively, wherein the structural formulas of comparative compounds a and h are as follows: .

[0064] The driving voltage, luminous efficiency, BI value and lifetime of the organic electroluminescent devices obtained by the above-mentioned devices in Examples 1-50 and Comparative Examples 1-8 were characterized at a brightness of 1000 nits. The test results are shown in Table 1.

[0065] Table 1. Results of luminous properties test (luminance value 1000 nits) Those skilled in the art will know that in blue top-emitting devices, luminous efficiency is greatly affected by chromaticity. Therefore, taking into account the influence of chromaticity on efficiency, the ratio of luminous efficiency to CIEy is defined as the BI value, i.e., BI = (cd / A) / CIEy.

[0066] This invention provides a compound with hole-blocking functionality. A triazine derivative is linked to a naphthalene substituted with dibenzofuran or dibenzothiophene via biphenyl. The triazine derivative exhibits high electron mobility, which helps enhance the hole-blocking ability of the material and promotes electron transport, thereby increasing the fluorescence quantum yield, reducing the driving voltage, and enhancing luminous efficiency. The triazine derivative also possesses good rigidity, effectively improving the thermal stability of the material and extending its lifespan. Linking the triazine derivative with the naphthalene substituted with dibenzofuran or dibenzothiophene via biphenyl extends the conjugated chain, increases the fused ring structure, enhances the intramolecular electron delocalization, improves electron mobility, and simultaneously improves the thermal stability of the material. The resulting compound can be used as a hole-blocking layer material, offering advantages such as reduced driving voltage, improved luminous efficiency, and extended lifespan. The organic electroluminescent device of this invention has a driving voltage below 3.75V, a luminous efficiency above 7.86cd / A, and a T95 lifetime above 450h.

[0067] As can be seen from Table 1, compared with the existing organic electroluminescent devices provided by Device Comparative Examples 1 to 9, the OLED devices prepared using the compounds provided in the embodiments of the present invention (Examples 1 to 50) show a significant advantage in device lifetime, which is increased by 12.78% to 27.89% compared with the comparative examples. At the same time, it also improves the driving voltage and luminous efficiency of the device, with the driving voltage reduced by 2.13% to 10.61% and the luminous efficiency increased by 9.77% to 16.4%.

[0068] The difference between the comparative compounds a and b and the compound of the present invention is that the linking group L in the compound of the present invention is substituted on different benzene rings of the naphthyl group with dibenzofuranyl or dibenzothiopheneyl, while the corresponding substituents in the comparative compounds are substituted on the same side of the benzene ring of the naphthyl group. The mutual interference between the substituents on opposite sides is smaller, the molecular skeleton is more likely to maintain planarity, which is beneficial to the delocalization and transport of electrons on the molecular skeleton, and has stronger π-π interaction, which can effectively improve luminescence efficiency and electron mobility.

[0069] The difference between comparative compounds c, d, and g and the compounds of this invention lies in the different groups attached to the linking group L. The linked group in the compounds of this invention is naphthalene substituted with dibenzofuran or dibenzothiophene, while the corresponding group in the comparative compounds is a polycyclic fused ring group. Similarly, the difference between comparative compounds f and h and the compounds of this invention lies in the different substituents on the naphthalene. In this invention, the substituents on the naphthalene are dibenzofuran or dibenzothiophene, while the corresponding substituent in the comparative compounds is naphthyl. Among similar substances, the position and type of substituent both affect the triplet energy level and mobility, thus influencing the device performance in organic electroluminescence. Although the structures of the compounds in this invention are similar to those in the prior art, compounds conforming to the hole-blocking material structure described in this invention exhibit significantly improved lifetime, improved luminous efficiency, and reduced driving voltage compared to the comparative compounds.

[0070] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the compounds of the present invention and the organic electroluminescent devices containing them, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound with hole-blocking function, characterized in that, The compound with hole-blocking function has the structure shown in Formula I: ， Where L is ★ and * represent permissible linkage sites; ★ is linked to triazine derivatives, and * is linked to naphthyl groups. X is selected independently from O or S; Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, respectively, and their heteroatoms are one or more of O, S, N, Si, Ge, and Se. Furthermore, Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted C6-C18 heteroaryl, respectively, and their heteroatoms are one or more of O, S, N, and Si. In Formula I above, all hydrogen atoms are either substituted with deuterium or not substituted with deuterium.

2. The compound with hole-blocking function according to claim 1, characterized in that, The hole-blocking compound has a structure shown in any one of formulas I-1 to I-8: 。 3. The compound with hole-blocking function according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from the following substituted or unsubstituted groups: ； in In the radical group, the asterisk represents the linking site. The short lines on the Si atoms in the group represent the bonding sites; the bonding positions of other groups are any substituted positions.

4. The compound with hole-blocking function according to any one of claims 1-3, characterized in that, Substitution means being replaced by one, two or more substituents selected from the following: hydrogen, deuterium, halogen, cyano, trifluoromethyl, trimethylsilyl, trimethylgermanium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracene, phenanthrene, thiophene, furanyl, pyrrole, benzothiophene, benzofuranyl, pyridyl, indolyl, cyclopentyl, cyclohexyl, adamantane, or by substituents linked to two or more of the substituents shown above.

5. The compound with hole-blocking function according to any one of claims 1-3, characterized in that, The compound with hole-blocking function is any one of the following compounds: 。 6. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode; the organic layer includes a hole-blocking layer, the hole-blocking layer containing a compound having hole-blocking function as described in any one of claims 1-5.

7. The organic electroluminescent device according to claim 6, characterized in that, The organic layer further includes one or a combination of at least two of the following: a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a capping layer.

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