Host material, organic electroluminescent material containing double host and application thereof

Abstract

The application discloses a host material, an organic electroluminescent material containing double hosts and application thereof, and relates to the field of organic electroluminescent materials. The structure of the host material is shown in general formula 1: the first host material with a triazine skeleton is connected with two benzene mother nuclei at different positions of a naphthalene ring, and the rigid planar structure brings high glass transition temperature and thermal decomposition temperature. One benzene is fixed at an ortho position of the triazine ring, and a dibenzofuran is used as a main host group at another position of the triazine ring, which can efficiently transport electrons, balance electrons and holes, realize a wider exciton recombination region and higher exciton utilization, and effectively reduce the driving voltage and efficiency roll-off. Meanwhile, the second host with a triarylamine structure is matched, which can simultaneously enhance the hole transport and electron transport capacity, so that when the holes are injected into the p-type host and the electrons are injected into the n-type host, the driving voltage is reduced, and the luminous efficiency and the service life are also significantly enhanced.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials, and more specifically, to a host material, an organic electroluminescent material containing two hosts, and their applications. Background Technology

[0002] Organic electroluminescent devices are self-emissive devices that have attracted widespread attention in the panel display device industry due to their characteristics such as low driving voltage, high resolution, high brightness, fast response time, and flexibility, as well as the low production cost, easy processing, and high purity of raw materials.

[0003] Currently, OLED display technology has been applied in fields such as smartphones and tablets, and will be expanded to large-size applications such as televisions. However, compared with the requirements of actual product applications, the performance of OLED, such as luminous efficiency and lifespan, still needs to be further improved.

[0004] The luminescent material of an organic light-emitting diode (OLED) device is the most important factor determining the device's luminous efficiency. Functionally, it can be divided into host materials and dopant materials. The luminescent material can be used by mixing the host and dopants to improve color purity, luminous efficiency, and stability. Devices with excellent electroluminescence (EL) characteristics typically have a structure where a luminescent layer is formed by incorporating dopants into the host. When using such a dopant / host material system as the luminescent material, the host material significantly affects the efficiency and lifespan of the OLED device; therefore, selecting a suitable host material is crucial.

[0005] Therefore, the urgent task at present is to develop OLEDs with high efficiency and long lifespan. In particular, considering the EL characteristics required for medium and large OLED panels, it is imperative to develop luminescent materials that are superior to conventional luminescent materials and have excellent performance.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a host material, an organic electroluminescent material containing two hosts, and their applications.

[0008] This invention is implemented as follows: In a first aspect, the present invention provides a main material, the structure of which is shown in general formula 1: ; Wherein, Ar is selected from hydrogen, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl; L is selected from a linking bond, substituted or unsubstituted C6-C18 aryl; R1 is selected from substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C42 heteroaryl, substituted or unsubstituted oxyphosphoyl, substituted or unsubstituted silyl. Among them, heteroaryl includes a monocyclic aromatic group or a polycyclic aromatic system with at least one heteroatom, and the heteroatom includes O, S or N.

[0009] Secondly, the present invention provides an organic electroluminescent material comprising two main bodies, comprising a first main body material and a second main body material, wherein the mass ratio of the first main body material to the second main body material is 1:9-9:1; the first main body material is the main body material as described in any of the above embodiments, and the second main body material has the structure shown in general formula 2: General Formula 2; L1 to L3 are each independently selected from a linking bond, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 heteroaryl group; Ar1 ​​to Ar3 are each independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 heteroaryl group, or a substituted or unsubstituted C10-C30 fused ring group; wherein, the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system that includes at least one heteroatom, and the heteroatom includes O, S or N.

[0010] Thirdly, the present invention provides the application of the organic electroluminescent material containing a dual host as described in any of the above embodiments in the preparation of organic electroluminescent devices.

[0011] The present invention has the following beneficial effects: The organic electroluminescent material provided by this invention uses a triazine-based first host material with two benzenes attached to different positions on the naphthalene ring as parent nuclei. Its rigid planar structure results in a high glass transition temperature and thermal decomposition temperature. One benzene is fixed at the ortho position of the triazine ring, and the strong steric hindrance increases the dihedral angle with the triazine ring, suppressing intermolecular stacking and effectively inhibiting TTA (transitional catalytic oxidation). Simultaneously, a dibenzofuran group at another position on the triazine ring enables efficient electron transport, balancing electrons and holes, achieving a wider exciton recombination region and higher exciton utilization, effectively reducing the driving voltage and efficiency roll-off. Furthermore, the second host material, with a triarylamine structure, simultaneously enhances both hole and electron transport capabilities. Therefore, when holes are injected into the p-type host and electrons into the n-type host, the driving voltage is reduced while the luminous efficiency and lifetime are significantly enhanced. Attached Figure Description

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

[0013] Figure 1 The above is the hydrogen nuclear magnetic resonance spectrum of compound R001 provided in Example 1 of this invention. Detailed Implementation

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

[0015] This invention provides a main material, the structure of which is shown in general formula 1: ; Wherein, Ar is selected from hydrogen, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl; L is selected from a linking bond, substituted or unsubstituted C6-C18 aryl; R1 is selected from substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C42 heteroaryl, substituted or unsubstituted oxophosphoryl, substituted or unsubstituted silyl; wherein, the heteroaryl group comprises a monocyclic aromatic group or a polycyclic aromatic system with at least one heteroatom, and the heteroatom comprises O, S or N.

[0016] Optionally, Ar is selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted anthraquinone, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, and substituted or unsubstituted dibenzothiophene.

[0017] Optionally, L is selected from the linking bond, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthraquinone.

[0018] Optionally, R1 is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthrayl, substituted or unsubstituted pyrene, substituted or unsubstituted hydroxyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted benzothiophene, substituted or unsubstituted dibenzofuran, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted benzene The following groups are permitted: carbazolyl, substituted or unsubstituted naphthobenzofuranyl, substituted or unsubstituted naphthobenzothiophene, substituted or unsubstituted phenanthiazolyl, substituted or unsubstituted phenanthoxazolyl, substituted or unsubstituted benzodimethylfluorenyl, substituted or unsubstituted 9,9-spirodifluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted naphthooxazolyl, substituted or unsubstituted benzoxazolyl, substituted or unsubstituted tetraphenylsilyl, substituted or unsubstituted triphenylphosphine, or any one of the following groups:

[0019] in, Indicates connectable locations; This indicates that connections can be made at any available connection point.

[0020] Optionally, the substituted group in "substituted or unsubstituted" is selected from at least one of deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, phenyl, naphthyl, phenanthryl, anthracene, dibenzofuranyl, 9-phenyl-9H-carbazolyl, dibenzothiophene, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl and 9,9-spirodifluorenyl.

[0021] Optionally, the main material can be any of the following structures, but is not limited to: .

[0022] The above are some specific structural forms of the main material, but are not limited to the chemical structures listed. All compounds with simple transformations of groups within the defined range based on the general structural formula shown in Formula 1 should be included.

[0023] Furthermore, the present invention also provides an organic electroluminescent material containing two main bodies, comprising a first main body material and a second main body material, wherein the mass ratio of the first main body material and the second main body material is 1:9-9:1; the first main body material is the main body material of general formula 1 above, and the second main body material has the structure shown in general formula 2: General Formula 2; L1 to L3 are each independently selected from a linking bond, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 heteroaryl group; Ar1 ​​to Ar3 are each independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 heteroaryl group, or a substituted or unsubstituted C10-C30 fused ring group; wherein, the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system that includes at least one heteroatom, and the heteroatom includes O, S or N.

[0024] Optionally, Ar1 is selected from unsubstituted or substituted C6-C30 aryl groups, substituted or unsubstituted C3-C30 heteroaryl groups, where the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system that includes at least one heteroatom, and the heteroatom includes O, S or N. And / or, Ar2 and Ar3 are each independently selected from substituted or unsubstituted phenyl, biphenyl, or terphenyl; And / or, L2 and L3 are each independently selected from the connector key; And / or, L1 is selected from a linking bond, an unsubstituted C6-C18 aryl group, or a substituted or unsubstituted C6-C18 heteroaryl group, wherein the heteroatom is selected from O, S, or N; And / or, the substituted group in “substituted or unsubstituted” is selected from deuterium, cyano, methyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from O, S or N.

[0025] Optionally, the second body material may have any one of the following structures, but is not limited to:

[0026]

[0027]

[0028]

[0029] .

[0030] The above are some specific structural forms of the second main material, but are not limited to the chemical structures listed. All compounds based on the general structural formula 2, with simple transformations of the Ar1, Ar2, Ar3, L1, L2, and L3 groups within the previously defined range, should be included.

[0031] The present invention also provides a method for preparing the organic electroluminescent material containing two main bodies, the specific steps and conditions of which are as follows: I. Preparation method of intermediate products: (1) Under a nitrogen atmosphere, weigh 1 eq of reactant 1, 1-1.2 eq of reactant 2, and 3-4 eq of potassium carbonate and add them to the reaction system in sequence. Then add toluene, ethanol, water (2:1:1) and 0.05-0.08 eq of tetra(triphenylphosphine)palladium. Reflux at 60-90℃ for 12-24h under nitrogen protection, cool to 25℃, add pure water, stir for 30min, let stand for layering, separate the layers, use dichloromethane / petroleum ether as eluent, and perform column chromatography to obtain intermediate 1-1.

[0032] (2) Under a nitrogen atmosphere, weigh 1 eq of reactant 3, 1-1.2 eq of reactant 4, and 3-4 eq of potassium carbonate and add them to the reaction system in sequence. Then add toluene, ethanol, water (2:1:1) and 0.05-0.08 eq of tetra(triphenylphosphine)palladium. Reflux at 60-90℃ for 12-24h under nitrogen protection, cool to 25℃, add pure water, stir for 30min, let stand for separation, separate the layers, and use dichloromethane / petroleum ether as eluent for column chromatography to obtain intermediates 1-2.

[0033] (3) Under a nitrogen atmosphere, weigh 1 eq intermediate 1-2, 1.5-2 eq reactant 5, and 1-2 eq potassium acetate and add them to the reaction system in sequence. Then add 1,4-dioxane, 0.02-0.04 eq tris(dibenzylideneacetone) bispalladium and 0.04-0.06 eq X-phos. Reflux at 80-100℃ for 12-24 h under nitrogen protection, cool to 25℃, add pure water, stir for 30 min, let stand for layering, separate the layers, use dichloromethane / petroleum ether as eluent, and perform column chromatography to obtain intermediate 1-3.

[0034]

[0035] II. Synthesis of the main materials: 1. Synthesis of the first main material (1) Under a nitrogen atmosphere, weigh 1 eq intermediate 1-1, 1-1.2 eq reactant 6, and 2-3 eq potassium carbonate and add them to the reaction flask in sequence. Then add tetrahydrofuran, water, and 0.02-0.04 eq tetratriphenylphosphine palladium. Under nitrogen protection, reflux at 60-80℃ for 24-48h, cool to 25℃, add pure water, stir for 30min, let stand for layering, separate the layers, use dichloromethane / petroleum ether as eluent, and perform column chromatography to obtain intermediate 1-4. (2) Under a nitrogen atmosphere, weigh 1 eq of intermediate 1-4, 1-1.2 eq of intermediate 1-3, and 2-3 eq of potassium carbonate and add them to the reaction flask in sequence. Then add tetrahydrofuran, water, and 0.02-0.04 eq of tetratriphenylphosphine palladium. Under nitrogen protection, reflux at 60-80℃ for 24-48h, cool to 25℃, add pure water, stir for 30min, let stand for layering, separate the layers, use dichloromethane / petroleum ether as eluent, and perform column chromatography to obtain intermediate 1-5. (3) Under a nitrogen atmosphere, 1 eq of intermediates 1-5, 1-1.2 eq of reactant 7 containing the R1 substituent, and 2-3 eq of potassium carbonate were weighed and added to the reaction flask in sequence. Then, tetrahydrofuran, water, and 0.02-0.04 eq of tetratriphenylphosphine palladium were added. Under nitrogen protection, the mixture was refluxed at 60-80℃ for 24-48 h, cooled to 25℃, and purified water was added. After stirring for 30 min, the mixture was allowed to stand for separation and the layers were separated. Using dichloromethane / petroleum ether as the eluent, column chromatography was performed to obtain general formula 1. The synthetic route is as follows:

[0036]

[0037] 2. Synthesis of the second main material (1) Weigh reactant 11 (1 eq), reactant 12 (1-1.2 eq), and sodium tert-butoxide (2-3 eq) and add them to the reaction vessel in sequence. Then add toluene as the reaction solvent. Under nitrogen protection, add catalysts Pd2(dba)3 (0.01-0.02 eq) and P(t-Bu)3 (0.02-0.04 eq). Reflux at 120°C for 24 hours under nitrogen protection. Then cool to 25°C, add pure water, stir for 30 minutes, let stand for layering, separate the liquid and liquid, and perform column chromatography to obtain intermediate 2-1.

[0038] (2) The synthesis method of general formula 2 is the same as that of intermediate 2-1, and will not be repeated here.

[0039]

[0040] Furthermore, this invention also provides the application of a dual-host organic electroluminescent material in the fabrication of organic electroluminescent devices.

[0041] The organic electroluminescent device includes a first electrode, an organic electroluminescent material layer, and a second electrode; the organic electroluminescent material layer includes a light-emitting layer, which includes a doped material and an organic electroluminescent material containing two main bodies; the mass ratio of the organic electroluminescent material containing two main bodies to the doped material is (1-99):(99-1).

[0042] Specifically, in this invention, the organic electroluminescent device includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode.

[0043] The anode material is preferably a material with a large work function to facilitate the injection of holes into the organic material layer. The anode material includes: 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 is not limited thereto.

[0044] The cathode material is preferably a material with a small work function to facilitate the injection of electrons into the organic material layer. Cathode materials include: 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; but are not limited to these.

[0045] 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.

[0046] The hole injection layer material is a material that receives holes from the anode under low voltage. 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.

[0047] Hole transport layer 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 layer materials include, but are not limited to, arylamine-based organic materials, conductive polymers, and block copolymers having both conjugated and non-conjugated portions.

[0048] An electron blocking layer is disposed between the hole transport layer and the light-emitting layer, and the electron blocking layer material includes an organic material based on arylamine.

[0049] A hole blocking layer is disposed between the hole transport layer and the light-emitting layer, and the hole blocking layer material includes triazine-based compounds.

[0050] The electron transport region includes an electron transport layer and an electron injection layer.

[0051] The electron transport layer promotes electron transport. Electron transport materials are materials with high electron mobility that receive electrons from the cathode and transport them to the light-emitting layer. Electron transport materials include, but are not limited to, Al complexes of 8-hydroxyquinoline, Alq3 complexes, organic free radical compounds, and hydroxyflavonoid-metal complexes. The thickness of the electron transport layer ranges from 1 nm to 50 nm, preventing a decrease in electron transport properties and an increase in driving voltage.

[0052] The electron injection layer promotes electron injection. Electron injection materials are those capable of transporting electrons, exhibiting excellent electron injection effects on the luminescent layer or luminescent material, preventing excitons generated in the luminescent layer from migrating to the hole injection layer, and possessing excellent thin-film formation capabilities. Electron injection layer materials include fluorenones, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, azoles, diazoles, triazoles, imidazoles, perylenetetracarboxylic acid, fluorenemethane, anthrones, and their derivatives, metal complexes, and nitrogen-containing five-membered ring derivatives, but are not limited to these.

[0053] In this invention, the organic electroluminescent device can be a top-emitting, bottom-emitting, or dual-sided emitting type. The organic electroluminescent device can be used in organic solar cells, electronic paper, organic photoreceptors, or organic thin-film transistors.

[0054] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0055] Example 1: Preparation of compound R001 (1) Under a nitrogen atmosphere, 1 eq of (3,6-dichloronaphth-2-yl)boric acid (CAS: 2000289-19-82), 1 eq of phenylboric acid (CAS: 98-80-6), and 2 eq of potassium carbonate were weighed and added to the reaction flask in sequence. Then, tetrahydrofuran, water, and 0.02 eq of tetratriphenylphosphine palladium were added. Under nitrogen protection, the mixture was refluxed at 80°C for 24 h, cooled to 25°C, and purified water was added. After stirring for 30 min, the mixture was allowed to stand and separate into layers. The layers were separated, and column chromatography was performed using dichloromethane / petroleum ether as the eluent to obtain intermediate R001-1 (yield 63%, HPLC > 95%). The synthetic route is as follows:

[0056] (2) Under a nitrogen atmosphere, 1 eq of R001-1, 1 eq of 2-chloro-4-dibenzofuran-1-yl-6-phenyl-1,3,5-triazine (CAS:1883265-32-4), and 2 eq of potassium carbonate were weighed and added to the reaction flask in sequence. Then, tetrahydrofuran, water, and 0.02 eq of tetratriphenylphosphine palladium were added. Under nitrogen protection, the mixture was refluxed at 80°C for 24 h, cooled to 25°C, and purified water was added. After stirring for 30 min, the mixture was allowed to stand for separation and the layers were separated. Using dichloromethane / petroleum ether as the eluent, column chromatography was performed to obtain product R001 (yield 83%, HPLC > 99%, mass spectrometry value 601.23, elemental analysis values: C: 85.73; H: 4.57; N: 6.99; O: 2.71, and the 1H NMR spectrum is shown below). Figure 1 (As shown), the synthesis route is as follows: .

[0057] Example 2: Preparation of compound H010 N-(phenyl-d5)naphthyl-2-amine (1 eq), 9-chloro-2-phenylphenanthrene[3,4-d]oxazole (1 eq) and sodium tert-butoxide (2 eq) were weighed into a reaction flask, toluene was added, and catalysts Pd2(dba)3 (0.01 eq) and P(t-Bu)3 (0.02 eq) were added under nitrogen protection. The mixture was refluxed at 120 °C for 24 hours under nitrogen protection, then cooled to 25 °C, purified water was added, and the mixture was stirred for 30 min. After standing and separating the layers, the mixture was separated and subjected to column chromatography to obtain product H010 (yield 73%, HPLC > 99%, elemental analysis values: C: 85.79; H: 5.68; N: 5.42; O: 3.11, mass spectrometry value 517.87). The reaction route is shown below.

[0058] .

[0059] The synthesis methods for other compounds are the same as those in the above examples, and will not be described in detail here.

[0060] Device Example 1-60, Comparative Example 1-16 and Parallel Example 1-8: The device fabrication processes of Device Examples 1-60, Comparative Examples 1-16, and Parallel Examples 1-8 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 main materials are different. The specific selection of the first and second main materials is shown in Table 1. The structures of compounds D1 to D8 involved in the comparative and parallel examples are shown below:

[0061] Experimental Example: Fabrication of Red-Light Organic Electroluminescent Devices The fabrication method of organic electroluminescent devices is as follows: (1) The ITO (indium tin oxide) glass substrate with a thickness of 1500 angstroms was washed twice with distilled water, ultrasonically washed for 30 minutes, then washed twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 minutes each time), dried, and then transferred to a plasma cleaner for 5 minutes to obtain the ITO anode.

[0062] (2) In the vapor deposition machine, HIL is vacuum vapor deposited on the ITO anode surface obtained in step (1) with a thickness of 700 angstroms to obtain a hole injection layer.

[0063] (3) Vacuum evaporation of HTL on the surface of the hole injection layer obtained in step (2), first evaporating HTL1 with a thickness of 50 angstroms and then evaporating HTL2 with a thickness of 700 angstroms on its surface to form a hole transport layer.

[0064] (4) A light-emitting layer material is deposited on the surface of the hole transport layer by evaporation. A linear gradient co-evaporation method is used to obtain a thickness of 300 angstroms. The material of the light-emitting layer includes an organic electroluminescent material with dual hosts and a doped material. The mass ratio of the first host material and the second host material in the organic electroluminescent material with dual hosts is 6:4, and the mass ratio of the organic electroluminescent material with dual hosts to the doped material is 10:1. The organic electroluminescent materials with dual hosts are the host materials provided in Examples 1-60, Comparative Examples 1-16, and Parallel Examples 1-8.

[0065] (5) HBL is deposited on the surface of the light-emitting layer obtained in step (4) with a thickness of 100 angstroms to form a hole blocking layer.

[0066] (6) Vacuum vapor deposition of ETL on the surface of the hole blocking layer obtained in step (5) with a thickness of 300 angstroms is obtained to obtain the electron transport layer.

[0067] (7) Vacuum vapor deposition of EIL (Liq) on the surface of the electron transport layer obtained in step (6) with a thickness of 15 angstroms is obtained to obtain the electron injection layer.

[0068] (8) A 1200 angstrom layer of Al is deposited on the surface of the electron injection layer obtained in step (7) to form a cathode, thereby obtaining the organic electroluminescent device.

[0069] The structures of HIL, HTL1, HTL2, doped materials Dopant, HBL, ETL, and EIL are as follows:

[0070] .

[0071] The driving voltage, luminous efficiency, and time (lifetime; T95) of the organic electroluminescent device at a brightness of 3000 nits were tested. The test results are shown in Table 1.

[0072] Table 1. Statistical Table of Main Material Selection and Test Results for Different Organic Electroluminescent Devices

[0073] As can be seen from the comparison of Comparative Examples 1-16, using a combination of the first and second main materials as the main material of the light-emitting layer can significantly improve luminous efficiency and lifespan. Using only one of them will result in a significant decrease in the luminous efficiency of the device, a noticeable shortening of the lifespan, and an increase in voltage. As can be seen from the comparison of Comparative Examples 1-8 and Comparative Examples 13-16, the device made with the first main material of the present invention has significantly better performance than the main materials D1-D8 of the comparative examples.

[0074] A comparison of device examples 1-60 with parallel examples 1-8 shows that the efficiency of parallel examples 1-8 is 36.6-38.8 cd / A, the driving voltage is 4.45-4.69 V, and the lifetime is 563-591 h. In contrast, the luminous efficiency of device examples 1-60 of the present invention is 46.2-48.6 cd / A, which is significantly higher than that of parallel examples 1-8; the driving voltage is 3.58-3.75 V, which is significantly lower than that of parallel examples 1-8; and the lifetime is 772-805 h, which is much higher than that of parallel examples 1-8.

[0075] Compared to D2-D8, this application substitutes two phenyl groups at specific positions on the naphthalene ring, expanding the conjugated system and appropriately lowering T1 to make it more suitable for red light host devices. It also enhances overall rigidity and volume, resulting in higher glass transition temperature and thermal decomposition temperature. Furthermore, fixing dibenzofuran at the first position offers the following advantages: moderate upward shift of the HOMO energy level for energy level modulation; narrowing the band gap, which is beneficial for red light emission; more flexible energy level matching; enhanced carrier balance; improved hole transport; synergistic effect with hole-transporting host devices; improved recombination efficiency; good spectral stability; good molecular planarity; reduced non-radiative transitions; high color purity; suppression of quenching; and reduced aggregation through steric hindrance design, improving solid-state luminescence efficiency. Other substitution sites, being closer to oxygen atoms, may cause excessive upward shift of the HOMO energy level due to excessively high electron density, resulting in an excessively narrow band gap (potentially biased towards the near-infrared), which is detrimental to red light purity modulation. Additionally, compared to D1, the substitution positions on the naphthalene ring in this application provide better steric hindrance, reducing concentration quenching.

[0076] In summary, the organic electroluminescent material provided by this invention uses a triazine-based first host material with two benzenes connected at different positions on the naphthalene ring as the parent nucleus. Its rigid planar structure results in a high glass transition temperature and thermal decomposition temperature. One benzene is fixed at the ortho position of the triazine ring, and the strong steric hindrance effect increases the dihedral angle with the triazine ring, suppressing intermolecular stacking and effectively inhibiting TTA (transient ionization and catalytic degradation). Simultaneously, a dibenzofuran group at another position on the triazine ring enables efficient electron transport, balancing electrons and holes, achieving a wider exciton recombination region and higher exciton utilization, effectively reducing the driving voltage and efficiency roll-off. Furthermore, the combination with a second host material having a triarylamine structure enhances both hole and electron transport capabilities. Therefore, when holes are injected into the p-type host and electrons are injected into the n-type host, the driving voltage is reduced while the luminous efficiency and lifetime are significantly enhanced.

[0077] 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, The structural formula of the main material is shown in Figure 1: ； Wherein, Ar is selected from hydrogen, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl; L is selected from a linking bond, substituted or unsubstituted C6-C18 aryl; R1 is selected from substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C6-C42 heteroaryl, substituted or unsubstituted oxophosphoryl, substituted or unsubstituted silyl; wherein, the heteroaryl group comprises a monocyclic aromatic group or a polycyclic aromatic system with at least one heteroatom, and the heteroatom comprises O, S or N.

2. The main material according to claim 1, characterized in that, Ar is selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted anthraquinone, substituted or unsubstituted phenanthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, and substituted or unsubstituted dibenzothiophene.

3. The main material according to claim 1, characterized in that, L is selected from the linking bond, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthraquinone.

4. The main material according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted anthrayl, substituted or unsubstituted pyrene, substituted or unsubstituted hydroxyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted benzothiophene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted 9-phenyl-9H-carbazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted benzocarbazolyl. Azolium, substituted or unsubstituted naphthobenzofuranyl, substituted or unsubstituted naphthobenzothiophene, substituted or unsubstituted phenanthiazolyl, substituted or unsubstituted phenanthoxazolyl, substituted or unsubstituted benzodimethylfluorenyl, substituted or unsubstituted 9,9-spirodifluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted naphthooxazolyl, substituted or unsubstituted benzooxazolyl, substituted or unsubstituted tetraphenylsilyl, substituted or unsubstituted triphenylphosphine, or any one of the following groups: in, Indicates connectable locations; This indicates that connections can be made at any available connection point.

5. The main material according to any one of claims 1-4, characterized in that, The substituted or unsubstituted group is selected from at least one of deuterium, fluorine, cyano, methyl, trifluoromethyl, tert-butyl, phenyl, naphthyl, phenanthryl, anthracene, dibenzofuranyl, 9-phenyl-9H-carbazolyl, dibenzothiophene, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, and 9,9-spirodifluorenyl.

6. The main material according to any one of claims 1-4, characterized in that, The main material is any one of the following structures: 。 7. An organic electroluminescent material containing two main components, characterized in that, It includes a first main material and a second main material, wherein the mass ratio of the first main material to the second main material is 1:9-9:1; the first main material is the main material as described in any one of claims 1-6, and the second main material has the structure shown in general formula 2: General Formula 2; L1 to L3 are each independently selected from a linking bond, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C6-C30 heteroaryl group; Ar1 ​​to Ar3 are each independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 heteroaryl group, or a substituted or unsubstituted C10-C30 fused ring group; wherein, the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system that includes at least one heteroatom, and the heteroatom includes O, S or N.

8. The organic electroluminescent material containing two main bodies according to claim 7, characterized in that, Ar1 is selected from unsubstituted or substituted C6-C30 aryl groups or substituted or substituted C3-C30 heteroaryl groups, where the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system that includes at least one heteroatom, and the heteroatom includes O, S or N. And / or, Ar2 and Ar3 are each independently selected from substituted or unsubstituted phenyl, biphenyl, or terphenyl; And / or, L2 and L3 are each independently selected from the connector key; And / or, L1 is selected from a linking bond, an unsubstituted C6-C18 aryl group, or a substituted or unsubstituted C6-C18 heteroaryl group, wherein the heteroatom is selected from O, S, or N; And / or, the substituted or unsubstituted group is selected from deuterium, cyano, methyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from O, S or N.

9. The organic electroluminescent material containing two main bodies according to claim 7, characterized in that, The second body material has any one of the following structures: 。 10. The use of the organic electroluminescent material containing a dual host as described in any one of claims 7-9 in the fabrication of organic electroluminescent devices.

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