Host material, preparation method thereof and organic electroluminescent device

Abstract

The invention provides a host material, a preparation method thereof and an organic electroluminescent device, the structural general formula of the host material is a chemical formula I. The structure of the host material is composed of a dibenzofuran (or dibenzothiophene)-carbazole-o-phenylene-triazine group, multiple targets of carrier transport balance, high triplet state energy level, good thermal / morphological stability, inhibition of exciton quenching and the like are achieved on the molecular level. And finally, the advantages of high luminous efficiency, low driving voltage, low efficiency roll-off, long service life and the like are embodied on the device level.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence, and relates to a host material, its preparation method, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have shown broad application prospects in flat panel displays and solid-state lighting. Among them, phosphorescent OLEDs have attracted much attention because they can utilize triplet excitons and theoretically achieve 100% internal quantum efficiency. High-performance host materials are crucial for achieving efficient and stable phosphorescent OLEDs.

[0003] Currently, commonly used host material systems still face many challenges. Carrier transport imbalances lead to narrow exciton recombination regions close to the electrode interface, easily causing severe efficiency roll-off and device lifetime degradation. Multi-component co-evaporation processes are difficult to control precisely, have poor repeatability, and may pose a risk of phase separation under long-term operation, affecting device stability. Simple donor-acceptor direct connections may result in excessive molecular conjugation, leading to a lower triplet energy level, failing to meet the high triplet energy level requirements of green, especially high-efficiency, green phosphorescent guests. Overly planar molecular structures are prone to forming dense π-π packing, causing concentration quenching and impairing luminescence efficiency.

[0004] Therefore, there is an urgent need in this field to develop a new type of high-performance host material to prepare green phosphorescent OLED devices with high luminous efficiency, low roll-off, and long lifespan. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a host material, its preparation method, and an organic electroluminescent device. The host material of the present invention is composed of dibenzofuran (or dibenzothiophene)-carbazole-o-phenylene-triazine groups, achieving multiple objectives at the molecular level, including carrier transport balance, high triplet energy level, good thermal / morphological stability, and suppression of exciton quenching. Ultimately, at the device level, this manifests as advantages such as high luminous efficiency, low driving voltage, low efficiency roll-off, and long lifespan.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] On one hand, the present invention provides a host material, the general structural formula of which is chemical formula I:

[0008]

[0009] in,

[0010] X is selected from O or S;

[0011] R1, R2, R3, R4, and R5 are independently selected from hydrogen or deuterium;

[0012] n1, n2, and n5 are independently selected from 0, 1, 2, 3, and 4;

[0013] n3 and n4 are independently selected from 0, 1, 2, and 3;

[0014] Ar1 and Ar2 are each independently selected from the following groups, either unsubstituted or deuterated:

[0015]

[0016] * indicates the linking site of a functional group;

[0017] The hydrogen in the chemical formula I is either completely replaced by deuterium, partially replaced by deuterium, or not replaced by deuterium.

[0018] Furthermore, the host material has the structure shown in the following chemical formula I-A or chemical formula I-B:

[0019] .

[0020] Furthermore, the aforementioned main material is selected from any one of the following compounds:

[0021] .

[0022] The phosphorescent host layer material of the present invention can be prepared by synthesis methods known to those skilled in the art, or preferably by the following reaction process.

[0023]

[0024] In the above formula, X, Ar1, Ar2, R1-R5, and n1-n5 are as defined in the above chemical formula I; Hal1 and Hal2 independently represent Br and Cl.

[0025] In contrast to the complex raw materials that are not publicly available, the invention will employ classic methods such as Suzuki coupling reaction and borate esterification reaction for synthesis.

[0026] Step 1 specifically includes the following processes:

[0027] Add raw material A (1.0 eq), pinacol diborate (1.0-2.0 eq), and potassium acetate (2.0-4.0 eq) to a three-necked flask, then add 1,4-dioxane. Under nitrogen purging, add [1,1'-bis(diphenylphosphine)(ferrocene)]palladium dichloride (0.01-0.05 eq), heat to 100-110℃, and reflux for 0.5-20 h. Detect the reaction using thin-layer chromatography. After the reaction is complete, slightly lower the temperature, add dichloromethane and water for extraction, separate the liquid and liquid phases, retain the combined organic phases, and concentrate them. Purify the intermediate 1 using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:10) by column chromatography.

[0028] Step 2 specifically includes the following processes:

[0029] In a three-necked flask, intermediate 1 (1.0 eq) and raw material B (1.0-1.2 eq) were added, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Under nitrogen purging, tetrakis(triphenylphosphine)palladium (0.01-0.03 eq) and potassium carbonate (2.0-4.0 eq) or palladium acetate (0.02-0.05 eq), X-Phos (0.1-0.3 eq) and cesium carbonate (2.0-4.0 eq) were added. The mixture was heated to 85℃-95℃ and refluxed for 1-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 2 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:10).

[0030] Step 3 specifically includes the following processes:

[0031] In a three-necked flask, intermediate 2 (1.0 eq), pinacol diborate (1.0-2.0 eq), and potassium acetate (2.0-4.0 eq) were added, followed by 1,4-dioxane. Under nitrogen purging, tris(dibenzylacetone)dipalladium (0.01-0.05 eq) and X-Phos (0.1-0.3 eq) were added. The mixture was heated to 110-120 °C and refluxed for 1-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 3 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:10).

[0032] Step 4 specifically includes the following processes:

[0033] Intermediate 3 (1.0 eq) and raw material C (1.0-1.2 eq) were added to a three-necked flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Tetra(triphenylphosphine)palladium (0.01-0.03 eq) and potassium carbonate (2.0-4.0 eq) were added under nitrogen purging. The temperature was raised to 85℃-95℃ and refluxed for 1-24 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was lowered slightly, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. The solution of dichloromethane and petroleum ether (V:V = 1:3-1:10) was purified by column chromatography to obtain chemical formula I.

[0034] On the other hand, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, the organic layer comprising a light-emitting layer comprising the host material as described above.

[0035] Preferably, the light-emitting layer comprises a host material and a dopant material, wherein the host material is the host material as described above.

[0036] Preferably, the organic layer further includes at least one of a hole injection layer, a hole transport layer, a hole transport auxiliary layer, an electron blocking layer, a light emission auxiliary layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The compound structure of this invention is a carbazole group linked to the 4th position of a dibenzofuran group or a dibenzothiophene group at the 3-position, and the N on the carbazole is then linked to a triazine group via a bridging phenylene group at the ortho position. As a green light host material, this results in a device with low driving voltage, low luminous efficiency, low efficiency roll-off, and long lifespan.

[0039] In the compound structure of this invention, the carbazole group provides excellent hole transport capability, the triazine group provides electron transport capability, and the dibenzofuran or dibenzothiophene group itself also has a certain electron affinity, synergistically enhancing electron injection and transport with the triazine. This structured compound has a balanced bipolar carrier transport capability, enabling the material to transport holes and electrons simultaneously and in a balanced manner. This ensures that electrons and holes meet extensively within the light-emitting layer to form excitons, rather than concentrating near a certain electrode, thereby expanding the exciton recombination region and improving luminous efficiency. Moreover, the carbazole, dibenzofuran, dibenzothiophene, and triazine groups are all rigid, planar aromatic structures, resulting in high glass transition temperatures and thermal decomposition temperatures. This makes the material less prone to decomposition during vacuum evaporation, and the resulting film is very stable during device operation and storage, and does not easily crystallize, thus significantly extending the device's lifespan. Furthermore, the relatively high HOMO energy levels of the carbazole and dibenzofuran or dibenzothiophene in the compound structure of this invention are beneficial for injecting holes from adjacent hole transport layers. The low LUMO level of triazine facilitates electron injection from adjacent electron transport layers. Through bridging connections, the HOMO of the entire molecule is mainly distributed in the donor region, while the LUMO is mainly distributed in the acceptor region, achieving orbital separation and resulting in a small singlet-tritt energy level difference. This allows for energy level matching with commonly used electrode / functional layer materials, reducing the injection barrier and lowering the device driving voltage. Simultaneously, it ensures that the triplet energy level of the host is higher than that of the green phosphorescent guest, effectively transferring energy to the guest and preventing energy backflow from the guest to the host—effectively "confining" excitons to the luminescent guest. Furthermore, the carbazole and triazine groups are connected via ortho-phenylene groups. This ortho-connection introduces a large twist angle between the carbazole nitrogen atom and the triazine, reducing direct electronic coupling between the donor and acceptor and helping to maintain a high triplet energy level. The twisted rigid structure also effectively suppresses close packing and π-π packing of molecules in the thin film state, thus avoiding concentration quenching and excito-association formation, which is beneficial for forming a uniform and stable amorphous thin film. Attached Figure Description

[0040] Figure 1 The above is the proton NMR spectrum of compound 1 provided in Example 1 of this invention.

[0041] Figure 2 The proton NMR spectrum of compound 234 provided in Example 2 of this invention. Detailed Implementation

[0042] 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.

[0043] Additionally, 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 issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0044] Example 1

[0045]

[0046] Step 1 specifically includes the following processes:

[0047] In a three-necked flask, raw material A-1 (1.0 eq, CAS No.: 2054576-41-7), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added, followed by 1,4-dioxane. Under nitrogen purging, [1,1'-bis(diphenylphosphine)(ferrocene)]palladium dichloride (0.02 eq) was added, and the mixture was heated to 100 °C and refluxed for 8 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. The intermediate 1-1 (yield: 72.3%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (volume ratio V:V = 1:5).

[0048] Step 2 specifically includes the following processes:

[0049] Intermediate 1-1 (1.0 eq) and starting material B-1 (1.1 eq, CAS No.: 26608-06-0) were added to a three-necked flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Tetra(triphenylphosphine)palladium (0.02 eq) and potassium carbonate (3.0 eq) were added under nitrogen purging. The mixture was heated to 95 °C and refluxed for 4 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 2-1 (yield: 75.9%) was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4).

[0050] Step 3 specifically includes the following processes:

[0051] Intermediate 2-1 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a three-necked flask, followed by 1,4-dioxane. Tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.3 eq) were added under nitrogen purging. The mixture was heated to 110 °C and refluxed for 14 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction. The mixture was separated, and the organic phases were combined and concentrated. Intermediate 3-1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) (yield: 78.8%).

[0052] Step 4 specifically includes the following processes:

[0053] Intermediate 3-1 (1.0 eq) and starting material C-1 (1.0 eq, CAS No.: 1472062-94-4) were added to a three-necked flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Tetra(triphenylphosphine)palladium (0.03 eq) and potassium carbonate (4.0 eq) were added under nitrogen purging. The mixture was heated to 95 °C and refluxed for 18 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Compound 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) (yield: 83.5%).

[0054] The obtained compound 1 was analyzed, and the results are as follows:

[0055] HPLC purity: >99.8%.

[0056] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0057] Test value ((ESI, m / Z): [M+H]) + ): 716.52.

[0058] Elemental analysis:

[0059] The test values ​​were: C, 85.09; H, 4.63; N, 7.98; O, 2.37.

[0060] The proton NMR spectrum of compound 1 is shown below. Figure 1 As shown.

[0061] Example 2

[0062]

[0063] Step 1 specifically includes the following process: (Same as Step 1 in Example 1, raw material A-1 and raw material A-234 are the same substances, and intermediate 1-1 and intermediate 1-234 are the same substances.)

[0064] In a three-necked flask, raw material A-234 (1.0 eq, CAS No.: 2054576-41-7), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added, followed by 1,4-dioxane. Under nitrogen purging, [1,1'-bis(diphenylphosphine)(ferrocene)]palladium dichloride (0.02 eq) was added, and the mixture was heated to 100 °C and refluxed for 8 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. The intermediate 1-234 (yield: 72.3%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:5).

[0065] Step 2 specifically includes the following processes:

[0066] Intermediate 1-234 (1.0 eq) and starting material B-234 (1.1 eq, CAS No.: 97511-04-1) were added to a three-necked flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Tetra(triphenylphosphine)palladium (0.02 eq) and potassium carbonate (3.0 eq) were added under nitrogen purging. The mixture was heated to 95 °C and refluxed for 3 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 2-234 (yield: 76.2%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5).

[0067] Step 3 specifically includes the following processes:

[0068] Intermediate 2-234 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a three-necked flask, followed by 1,4-dioxane. Tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.3 eq) were added under nitrogen purging. The mixture was heated to 110 °C and refluxed for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction. The mixture was separated, and the organic phases were combined and concentrated. Intermediate 3-234 (yield: 80.4%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4).

[0069] Step 4 specifically includes the following processes:

[0070] Intermediate 3-234 (1.0 eq) and starting material C-234 (1.0 eq, CAS No.: 2648980-69-0) were added to a three-necked flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Tetra(triphenylphosphine)palladium (0.03 eq) and potassium carbonate (4.0 eq) were added under nitrogen purging. The mixture was heated to 95 °C and refluxed for 16 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and dichloromethane and water were added for extraction and separation. The organic phases were combined and concentrated. Compound 234 (yield: 83.9%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5).

[0071] The obtained compound 234 was analyzed, and the results are as follows:

[0072] HPLC purity: >99.7%.

[0073] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0074] Test value ((ESI, m / Z): [M+H]) + ): 796.47.

[0075] Elemental analysis:

[0076] The test values ​​were: C, 82.52; H, 4.18; N, 7.18; O, 2.14; S, 4.14.

[0077] The proton NMR spectrum of compound 234 is shown below. Figure 2 As shown.

[0078] Furthermore, other compounds of the present invention can be obtained by referring to the synthesis methods of the examples listed above, so they will not be listed one by one here.

[0079] Device Example 1: Fabrication of Organic Electroluminescent Devices

[0080] The structure of the fabricated OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / CPL.

[0081] a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 Å was cleaned twice in distilled water and ultrasonically washed for 30 min. Then it was cleaned twice more in distilled water and ultrasonically washed for 10 min. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 min each time). After drying, it was transferred to a plasma cleaner for 5 min and then sent to a vapor deposition machine. Using this substrate as the anode, other functional layers were sequentially vapor deposited on it.

[0082] b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s, wherein the deposition rate ratio of HT to P-dopant is 97:3, and the thickness is 10 nm.

[0083] c. HTL (Hole Transport Layer): A 125nm HT layer is vacuum-deposited on top of the hole injection layer at a deposition rate of 1.5Å / s as the hole transport layer.

[0084] d. Prime (light-emitting auxiliary layer): A 45nm Prime layer was vacuum-deposited on the hole transport layer at a deposition rate of 1.0Å / s as a light-emitting auxiliary layer.

[0085] e. EML (Emitting Layer): Then, on the above-mentioned emitting auxiliary layer, a dual host material (compound 1 provided in Example 1 above as the first host compound and Host-2 as the second host compound) and a dopant are vacuum-deposited at a deposition rate of 1 Å / s as the emitting layer, with a total thickness of 40 nm, wherein the deposition rate ratio of the first host compound, the second host compound and the dopant compound is 45:45:10.

[0086] f. HBL (hole blocking layer): A hole blocking layer HB with a thickness of 5 nm is vacuum-deposited at a deposition rate of 0.5 Å / s.

[0087] g. ETL (Electron Transport Layer): ET and Liq layers with a thickness of 30 nm were vacuum-deposited at a deposition rate of 1 Å / s. The deposition rate ratio of ET to Liq was 50:50.

[0088] h. EIL (Electron Injection Layer): A 1 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form the electron injection layer.

[0089] 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.

[0090] j. CPL (Covering Layer): A 65 nm thick CPL is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as a covering layer.

[0091] k. Subsequently, the vapor-deposited substrate is encapsulated. First, the cleaned cover plate is coated with UV adhesive using an adhesive coating equipment. Then, the coated cover plate is moved to the lamination section, and the vapor-deposited substrate is placed on the top of the cover plate. Finally, the substrate and cover plate are laminated under the action of the lamination equipment, while the UV adhesive is cured by light.

[0092] The structural formulas of HT, P-dopant, Prime, Host-2, Dopant, HB, ET, and CPL used in Embodiment 1 of the above devices are shown below:

[0093] .

[0094] Referring to the method provided in Device Example 1 above, the corresponding compounds in Table 1 were selected to replace Compound 1, and the main material of the light-emitting layer was deposited by vapor deposition to prepare the corresponding organic electroluminescent devices, which are respectively referred to as Device Examples 2 to 158.

[0095] Device Comparison Example 1-17:

[0096] Comparative Examples 1-17 were constructed using the method described in Device Example 1 above, with the comparative compound aq replacing the main material (compound 1) of the light-emitting layer in Device Example 1. These were denoted as Comparative Examples 1-17, and the chemical structural formula of the comparative compound aq is as follows:

[0097] .

[0098] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 1 to 158 and Comparative Examples 1 to 17 were characterized at a brightness of 15000 nits. The test results are shown in Table 1 below.

[0099] Table 1 Device Test Results

[0100]

[0101]

[0102]

[0103] As can be seen from Table 1, the organic electroluminescent devices prepared using the light-emitting layer host material provided by the present invention in Examples 1-158 show significantly improved driving voltage, luminous efficiency and lifetime compared with the devices prepared using comparative compounds 1-17.

[0104]

[0105] Comparative compounds a, c, d, e and compounds 1, 149, 2, 150 are parallel comparative examples. The difference lies in the connection method between the carbazole group and the dibenzofuran group / dibenzothiophene group in the structure of comparative compounds a, c, d, e and compounds 1, 149, 2, 150 of the present invention. In the structure of the compounds of the present invention, the 4th position of the carbazole group is connected to the 3rd position of the dibenzofuran group / dibenzothiophene group. As can be seen from the device results in Table 1 above, in the device system of this application, the compound with this connection method has better device performance.

[0106]

[0107] Comparing compounds n, o, p with compounds 6, 154, 36 as parallel comparative examples, the difference lies in the structure. In comparative compounds n and o, the carbazole and triazine groups are linked via a para-phenylene group; in comparative compound p, the carbazole and triazine groups are linked via a meta-phenylene group, with an additional phenyl substituent on the phenyl group; while in compounds 6, 154, 36 of this invention, the carbazole and triazine groups are linked via an ortho-phenylene group. Compared to para or meta-linking, ortho-linking introduces a large twist angle between the carbazole nitrogen atom and the triazine, reducing direct electronic coupling between the donor and acceptor and helping to maintain a higher triplet energy level. The twisted rigid structure can also effectively suppress close packing and π-π packing of molecules in the thin film state, thereby avoiding concentration quenching and excitoassociation formation, which is beneficial for forming a uniform and stable amorphous thin film. This, in turn, is conducive to improving device performance, achieving higher luminous efficiency and longer lifespan.

[0108] The applicant declares that the present invention is illustrated through the above embodiments to demonstrate the main materials, preparation method, and organic electroluminescent device of the present invention. However, 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 main material, characterized in that, The general structural formula of the main material is chemical formula I: ； in, X is selected from O or S; R1, R2, R3, R4, and R5 are independently selected from hydrogen or deuterium; n1, n2, and n5 are independently selected from 0, 1, 2, 3, and 4; n3 and n4 are independently selected from 0, 1, 2, and 3; Ar1 and Ar2 are each independently selected from the following groups, either unsubstituted or deuterated: ； * indicates the linking site of a functional group; The hydrogen in the chemical formula I is either completely replaced by deuterium, partially replaced by deuterium, or not replaced by deuterium.

2. The main material according to claim 1, characterized in that, The host material is selected from any one of the following compounds: 。 3. 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, wherein the organic layer includes a light-emitting layer, and the light-emitting layer includes the host material as described in claim 1 or 2.

4. The organic electroluminescent device according to claim 3, characterized in that, The organic layer further includes at least one of the following: a hole injection layer, a hole transport layer, a hole transport auxiliary layer, an electron blocking layer, a light emission auxiliary layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

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