Electron transport layer material, preparation method and organic electroluminescent device

Abstract

The invention belongs to the field of organic electroluminescent materials, and discloses an electron transport layer material, a preparation method and an organic electroluminescent device, and the structural general formula of the electron transport layer material is shown in the specification. The compound provided by the invention is used as an electron transport layer material of the organic electroluminescent device, so that the device has low driving voltage, excellent luminous efficiency and long service life.

Description

Technical Field

[0001] The present invention belongs to the field of organic electroluminescent materials, and relates to an electron transport layer material, a preparation method, and an organic electroluminescent device. Background Art

[0002] An organic light-emitting diode (OLED) is a solid-state semiconductor device that uses organic materials to emit light under the action of an electric field. An OLED usually consists of multiple organic thin films sandwiched between two electrodes. A typical structure includes a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, an electron blocking layer, a light-emitting layer, an electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, a cover layer, etc. The electron transport layer plays a crucial role in organic light-emitting diodes (OLEDs), and its main function is to promote the efficient transport of electrons from the cathode to the light-emitting layer.

[0003] Although many materials are currently used as electron transport layer materials, their electron mobility is usually lower than the hole mobility of the hole transport layer, which can lead to carrier imbalance, and low electron mobility may result in reduced current efficiency because electrons cannot be effectively transported to the light-emitting layer, thus affecting light generation. Poor energy level matching between the electron transport layer and the cathode leads to difficult electron injection or low injection efficiency, which will increase the interface resistance and reduce the driving voltage of the device, thereby affecting the efficiency and lifespan of the device. Some electron transport layer materials will degrade after long-term operation, especially at high current densities. This degradation may be caused by thermal effects, chemical reactions, or charge accumulation, and will lead to a decline in device performance, such as brightness attenuation and shortened lifespan.

[0004] Therefore, designing a stable and efficient compound as the electron transport layer material in organic electroluminescent devices to overcome the deficiencies that occur in the actual application process is the focus of current research work. Summary of the Invention

[0005] The organic compound of the present invention uses a dibenzo five-membered ring fused tetramethyl-substituted cyclohexane structure (dimethyl-substituted cyclopentane) containing heteroatoms (O, S) as the core main body to enhance the conjugation degree of the structure, adjust the spatial configuration, reduce the influence of the external environment on the core skeleton, and improve the service life of the device. It can also increase the exciton recombination probability, which is beneficial to improving the light-emitting efficiency of the device. Then, by connecting a triazine group through a bridging L group (chemical bond, phenylene, biphenylene, naphthylene), an efficient electron transport channel can be formed, significantly improving the electron mobility of the entire material, and thus contributing to improving the efficiency of the entire device.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An electron transport layer material, the structural general formula of the electron transport layer material being Chemical Formula I:

[0008]

[0009] In Chemical Formula I:

[0010] X is independently selected from O or S;

[0011] Y represents -(CH 2 )n-, where n is an integer of 1 or 2;

[0012] Z 1 、Z 2 、Z 3 are each independently selected from C or N, and Y 1 、Y 2 、Y 3 has at most one N, and the rest are C;

[0013] L is selected from a chemical bond, a substituted or unsubstituted C6-C30 arylene group;

[0014] R 1 is independently selected from one of hydrogen, deuterium, cyano group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C5-C30 heteroaryl group, and its heteroatoms contain at least one of O, S, N, Si, Se;

[0015] n 1 is selected from an integer of 0, 1, 2, 3;

[0016] Ar 1 、Ar 2 are each independently selected from one of a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C5-C30 heteroaryl group, or a combination of the above aryl group and heteroaryl group, and its heteroatoms contain at least one of O, S, N, Si, Se;

[0017] Further preferably, Chemical Formula I is selected from the following Chemical Formula I-A to Chemical Formula I-B:

[0018]

[0019] Further preferably, L is selected from a chemical bond, a substituted or unsubstituted C6-C18 arylene group;

[0020] Further preferably, R 1Each independently selected from hydrogen, deuterium, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C7 cycloalkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C5-C12 heteroaryl, and at least one of its heteroatoms contains at least one of O, S, N, Si, Se;

[0021] More preferably, Ar 1 and Ar 2 Each independently selected from substituted or unsubstituted C6-C25 aryl, substituted or unsubstituted C5-C25 heteroaryl, or a combination of both of the above aryl and heteroaryl, and at least one of its heteroatoms contains at least one of O, S, N, Si, Se;

[0022] Even more preferably, L is independently selected from a chemical bond, phenylene, naphthylene, biphenylene;

[0023] Even more preferably, R 1 Each independently selected from hydrogen, deuterium, cyano, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, cyclobutane, cyclopentane, cyclohexane, phenyl, biphenyl, naphthyl, terphenyl, anthracenyl, phenanthryl, pyridyl, pyrimidinyl, triazinyl, quinolinyl, quinoxalinyl, 9,9-dimethylfluorenyl, spirobifluorenyl, dibenzofuranyl, dibenzothiophenyl, benzonaphthofuranyl, benzonaphthothiophenyl, benzonaphthofluorenyl, carbazolyl, benzocarbazolyl, methylphenyl, phenylnaphthyl, cyanophenyl, cyanopyridyl, phenylpyridyl, phenyldibenzofuranyl, phenyldibenzothiophenyl, phenyldimethylfluorenyl, phenylcarbazolyl, methylpyridyl, methylpyrimidinyl and any combination of the above;

[0024] Even more preferably, Ar 1 and Ar 2 Each independently selected from the following groups or any combination:

[0025]

[0026] In the present invention, the term "substituted" means substituted by one, two or more substituents selected from: deuterium, halogen group, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopentane, cyclohexane, trifluoromethyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, biphenyl, naphthyl, fluorenyl, dimethylfluorenyl, phenanthryl, anthracenyl, indenyl, triphenylene, pyrenyl, Base, furyl, thienyl, pyrrolyl, pyridyl, benzofuryl, benzothienyl, isobenzofuryl, dibenzofuryl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, benzindolyl, indazolyl, benzothiadiazolyl, carbazolyl, benzocarbazolyl, adamantane.

[0027] Furthermore, among the above-mentioned electron transport layer materials, any one selected from the compounds represented by the following structural formulas:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] The compounds of the present invention can be prepared by synthetic methods known to those skilled in the art, or preferably prepared according to the following reaction process.

[0038]

[0039] In the above formulas, X, Y, Z 1 -Z 3 , R 1 , n 1 , L, Ar 1 , Ar 2 are defined as in Chemical Formula I above; Hal 1 , Hal 2 independently represent Br, Cl.

[0040] Relative to the complex raw materials that are not disclosed, classical Suzuki coupling reactions, boric acid esterification reactions, etc. will be used for synthesis and applied to the present invention.

[0041] Step 1 specifically includes the following processes:

[0042] Add raw material A (1.0 eq), bis(pinacolato)diboron (1.0 - 2.0 eq) and potassium acetate (2.0 - 4.0 eq) into a three-necked flask, then add 1,4-dioxane, and pass N 2 Under this condition, add tris(dibenzylideneacetone)dipalladium(0) (0.02 - 0.10 eq) and X-Phos (0.1 - 0.2 eq), heat up to 110 - 120 °C, and reflux for 4 - 24 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it. Use a mixed solution of dichloromethane and petroleum ether (V:V = 1:3 - 1:8) to purify by column chromatography to obtain Intermediate 1.

[0043] Step 2 specifically includes the following process:

[0044] Add Intermediate 1 (1.0 eq) and raw material B (1.0 - 1.2 eq) into a three-necked flask, then add a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and pass N 2 Under this condition, add tetrakis(triphenylphosphine)palladium(0) (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), heat up to 85 °C - 95 °C, and reflux for 2 - 24 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it. Use a mixed solution of dichloromethane and petroleum ether (V:V = 1:3 - 1:8) to purify by column chromatography to obtain Chemical Formula I.

[0045] Advantages of the present invention

[0046] The organic compound of the present invention has a dibenzo-fused five-membered ring containing heteroatoms (O, S) and a tetramethyl-substituted cyclohexane structure (dimethyl-substituted cyclopentane) and a triazine group as the core main body. As an electron transport layer material, the device has a low driving voltage, excellent luminous efficiency and a long service life.

[0047] The lone pair electrons of the heteroatoms on the dibenzo-fused five-membered ring structure can form conjugation with the plane, thereby enhancing the conjugation degree of the structure, having a high mobility, and being beneficial to reducing the device voltage; introducing a tetramethyl-substituted cyclohexane (dimethyl-substituted cyclopentane) on the dibenzo-fused five-membered ring structure can adjust the spatial configuration, provide a better shielding effect, reduce the influence of the external environment on the core skeleton, improve the film-forming property of the material, enhance the device stability, and thus enhance the service life of the device. And it makes the band gap of the material larger, enhances the exciton blocking ability, so that the exciton recombination probability can be increased, which is beneficial to improving the luminous efficiency of the device.

[0048] Triazine is a strong electron acceptor with high electron affinity, capable of effectively attracting and conducting electrons. Introducing a bridging L group (phenylene, biphenylene, naphthylene) between the two can form an efficient electron transport channel, significantly enhancing the electron mobility of the entire material, thereby contributing to improving the efficiency of the entire device. It can also reduce the occurrence of large planar surfaces within the molecule, weaken the intermolecular interactions, and extend the service life of the device. Description of the Drawings

[0049] Figure 1 It is the nuclear magnetic resonance hydrogen spectrum of Compound 154 provided in Example 2 of the present invention. Detailed Embodiments

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0051] In addition, it should be noted that the values given in the following embodiments are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate value rather than an absolutely accurate numerical value.

[0052] Synthesis Example 1

[0053]

[0054] Step 1 specifically includes the following process:

[0055] Add raw material A-1 (1.0 eq, CAS No.: 3025110-20-4), bis(pinacolato)diboron (1.2 eq) and potassium acetate (3.0 eq) into a three-necked flask, then add 1,4-dioxane, and pass N 2 Under this condition, add tris(dibenzylideneacetone)dipalladium(0) (0.03 eq) and X-Phos (0.2 eq), heat up to 120 °C, and reflux for 20 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it, and purify it by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to obtain Intermediate 1 (yield: 78.2%).

[0056] Step 2 specifically includes the following process:

[0057] Add intermediate 1 (1.0 eq) and raw material B-1 (1.2 eq, CAS No.: 307929-32-4) into a three-necked flask, then add a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1), and pass N 2 In this case, add palladium acetate (0.05 eq), X-Phos (0.2 eq), and cesium carbonate (3.0 eq), heat up to 95 °C, and reflux for 13 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it. Use a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) to purify by column chromatography to obtain compound 1 (yield: 80.8%).

[0058] Detect and analyze the obtained compound 1, and the results are as follows:

[0059] HPLC purity: >99.8%.

[0060] Mass spectrometry test: A mass spectrometer of model Waters XEVO TQD, using ESI source.

[0061] Test value ((ESI, m / Z): [M+H] + ): 557.46.

[0062] Elemental analysis:

[0063] Calculated values are: C, 83.99; H, 5.60; N, 7.53; O, 2.87;

[0064] Test values are: C, 83.66; H, 5.76; N, 7.68; O, 2.99.

[0065] Synthesis Example 2

[0066]

[0067] Step 1 specifically includes the following process:

[0068] Add raw material A-154 (1.0 eq, CAS No.: 2155831-21-1), bis(pinacolato)diboron (1.2 eq), and potassium acetate (3.0 eq) into a three-necked flask, then add 1,4-dioxane, and pass N 2 In this case, add tris(dibenzylideneacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq), heat up to 120 °C, and reflux for 17 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it. Use a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to purify by column chromatography to obtain intermediate 100 (yield: 77.9%).

[0069] Step 2 specifically includes the following process:

[0070] Add intermediate 1 (1.0 eq) and raw material B-154 (1.2 eq, CAS No.: 2414945-60-9) into a three-necked flask, then add a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1), and pass N 2 Under this condition, add palladium tetrakis(triphenylphosphine) (0.03 eq) and potassium carbonate (3.0 eq), heat up to 95 °C, and reflux for 10 h; detect the reaction by thin-layer chromatography. After the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and liquid separation, retain the organic phase and then concentrate it. Use a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) to purify by column chromatography to obtain compound 154 (yield: 81.4%).

[0071] Detect and analyze the obtained compound 154, and the results are as follows:

[0072] HPLC purity: >99.6%.

[0073] Mass spectrometry test: A mass spectrometer of model Waters XEVO TQD, using an ESI source.

[0074] Test value ((ESI, m / Z): [M+H] + ): 545.38.

[0075] Elemental analysis:

[0076] Calculated values are: C, 79.24; H, 4.25; N, 7.70; O, 2.93; S, 5.88;

[0077] Test values are: C, 78.89; H, 4.39; N, 7.85; O, 3.06; S, 5.98.

[0078] 1H nuclear magnetic resonance spectrum: As Figure 1 (Compound 154) shown.

[0079] In addition, other compounds of the present invention can be obtained by referring to the synthesis methods of the above-listed examples, so they are not listed one by one here.

[0080] Device Example 1: Preparation of an organic electroluminescent device

[0081] The structure of the prepared OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / CPL.

[0082] a. ITO anode: The coating thickness is The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate is washed twice in distilled water, ultrasonically washed for 30 min, then repeatedly washed twice with distilled water and ultrasonically washed for 10 min. After washing, it is ultrasonically washed with methanol, acetone, and isopropyl alcohol in sequence (each washing for 5 min), dried, and then transferred to a plasma cleaner for 5 min of washing, and then sent to an evaporation coater. Using this substrate as the anode, other functional layers are evaporated on it in sequence.

[0083] b. HIL (hole injection layer): At the evaporation rate, the hole injection layer materials HT and P-dopant are vacuum-evaporated. Their chemical formulas are as shown below. The evaporation rate ratio of HT and P-dopant is 97:3, and the thickness is 10 nm.

[0084] c. HTL (hole transport layer): At the evaporation rate, 130 nm of HT is vacuum-evaporated on the hole injection layer as the hole transport layer.

[0085] d. Prime (luminescence assisting layer): At the evaporation rate, 5 nm of Prime is vacuum-evaporated on the hole transport layer as the luminescence assisting layer.

[0086] e. EML (emitting layer): Then, on the above-mentioned luminescence assisting layer, at the evaporation rate, a host material (Host) and a dopant material (Dopant) with a thickness of 30 nm are vacuum-evaporated as the emitting layer, where the evaporation rate ratio of Host and Dopant is 98:2.

[0087] f. HBL (hole blocking layer): At the evaporation rate, a hole blocking layer HB with a thickness of 5 nm is vacuum-evaporated.

[0088] g. ETL (electron transport layer): At the evaporation rate, the compound 1 and Liq provided in the above-mentioned embodiment with a thickness of 30 nm are vacuum-evaporated as the electron transport layer. The evaporation rate ratio of compound 1 and Liq is 50:50.

[0089] h. EIL (electron injection layer): At the evaporation rate, a 1-nm Yb film layer is evaporated to form the electron injection layer.

[0090] i. Cathode: At the evaporation rate ratio, magnesium and silver with a thickness of 13 nm are evaporated, and their evaporation rate ratio is 1:9 to obtain the OLED device.

[0091] j. CPL (cover layer): At The evaporation rate is used to vacuum evaporate a CPL with a thickness of 70 nm on the cathode as a covering layer.

[0092] k. Subsequently, the evaporated substrate is encapsulated. First, a coating equipment is used to coat the cleaned cover plate with UV glue, then the coated cover plate is moved to the lamination section, the evaporated substrate is placed on the upper end of the cover plate, and finally, the substrate and the cover plate are laminated under the action of a laminating device, while the UV glue is cured by light irradiation.

[0093] The structural formulas of HT, P-dopant, Prime, Host, Dopant, HB, and CPL used in the above Device Example 1 are as follows:

[0094]

[0095] Referring to the method provided in the above Device Example 1, the corresponding compounds in Table 1 are respectively selected to replace Compound 1 for the evaporation of the electron transport layer material, and the corresponding organic electroluminescent devices are prepared, which are respectively denoted as Device Examples 2 - 32.

[0096] Device Comparative Examples 1 - 6:

[0097] This comparative example provides an organic electroluminescent device. The only difference between the preparation method of this organic electroluminescent device and that of Device Example 1 is that this organic electroluminescent device uses the existing comparative compounds a - f to replace the electron transport layer material (Compound 1) in the above Device Example 1 for evaporation. Among them, the chemical structural formulas of the comparative compounds a - f are as follows:

[0098]

[0099] The driving voltage, BI value, and lifetime of the organic electroluminescent devices obtained in the above Device Examples 1 - 32 and Device Comparative Examples 1 - 6 are characterized at a brightness of 1000 (nits), and the test results are shown in Table 1 below:

[0100] Table 1 Device Test Results

[0101]

[0102]

[0103]

[0104] Those skilled in the art know that in a blue top-emitting device, the luminous efficiency is greatly affected by chromaticity. Therefore, considering the influencing factors of chromaticity on efficiency, the luminous efficiency is defined as the BI value in relation to the CIEy ratio, that is, BI = (cd / A) / CIEy, and the CIEy value is regulated within the range of 0.043 - 0.045 during the test.

[0105] It can be seen from the test data in Table 1 that the organic electroluminescent device prepared by using the compound of the present invention as the electron transport layer material has a lower driving voltage, excellent luminous efficiency and long service life.

[0106]

[0107] Comparative compound f and compounds 36 and 152 are parallel comparative examples respectively. The difference is that in comparative compound f, the parent nucleus structure is 9,9-dimethylfluorenyl fused with a dimethyl-substituted cyclopentane, while in compounds 36 and 152 of the present invention, the corresponding parent nucleus structures at the same position are dibenzofuran group and dibenzothiophene group fused with a dimethyl-substituted cyclopentane. These two fused ring structures are more stable, have good thermal stability, can withstand higher working temperatures, are not easily decomposed or degraded during the evaporation process, and effectively extend the service life of the device.

[0108] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electron transport layer material, characterized in that: The general structural formula of the electron transport layer material is shown in Chemical Formula I: In the chemical formula I: X is independently selected from O or S; Y represents -(CH2)n-, wherein n is an integer of 1 or 2; Z1, Z2, and Z3 are each independently selected from C or N, and Y1, Y2, and Y3 have at most one N, and the rest are C; L is selected from a chemical bond, a substituted or unsubstituted C6-C30 arylene group; R1 is independently selected from one of hydrogen, deuterium, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl, and its heteroatom contains at least one of O, S, N, Si, Se; n1 is an integer selected from 0, 1, 2, and 3; Ar1 and Ar2 are each independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C5-C30 heteroaryl group, or a combination of the above aryl and heteroaryl groups, and the heteroatom thereof contains at least one of O, S, N, Si, and Se.

2. The electron transport layer material according to claim 1, characterized in that The electron transport layer material has the following structures of Chemical Formula I-A to Chemical Formula I-B:

3. The electron transport layer material according to claim 1 or 2, characterized in that: L is selected from a chemical bond, a substituted or unsubstituted arylene group having C6-C18; R1 is independently selected from one of hydrogen, deuterium, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C7 cycloalkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C5-C12 heteroaryl, and its heteroatom contains at least one of O, S, N, Si, Se; Ar1 and Ar2 are each independently selected from a substituted or unsubstituted C6-C25 aryl group, a substituted or unsubstituted C5-C25 heteroaryl group, or a combination of the above aryl and heteroaryl groups, and the heteroatom thereof contains at least one of O, S, N, Si, and Se.

4. The electron transport layer material according to claim 1 or 2, characterized in that: L is independently selected from a chemical bond, phenylene, naphthylene, biphenylene; R1 is independently selected from hydrogen, deuterium, cyano, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, cyclobutane, cyclopentane, cyclohexane, phenyl, biphenyl, naphthyl, terphenyl, anthracenyl, phenanthryl, pyridyl, pyrimidyl, triazine, quinolyl, quinoxalinyl, 9,9-dimethylfluorenyl, spirobifluorenyl, dibenzofuranyl, dibenzothienyl, benzonaphthofuranyl, benzonaphthothienyl, benzonaphthofluorenyl, carbazolyl, benzocarbazolyl, methylphenyl, phenylnaphthyl, cyanophenyl, cyanopyridyl, phenylpyridyl, phenyldibenzofuranyl, phenyldibenzothienyl, phenyldimethylfluorenyl, phenylcarbazolyl, methylpyridyl, methylpyrimidyl and any combination thereof; Ar1 and Ar2 are each independently selected from the following groups or any combination thereof:

5. The electron transport layer material according to claim 1, characterized in that The term "substituted" means substituted with one, two or more substituents selected from the group consisting of deuterium, halogen, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopentane, cyclohexane, trifluoromethyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, biphenyl, naphthyl, fluorenyl, dimethylfluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, yl, furyl, thienyl, pyrrolyl, pyridyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, benzindolyl, indazolyl, benzothiadiazolyl, carbazolyl, benzocarbazolyl, and adamantane.

6. The electron transport layer material according to claim 1 or 2, characterized in that: The electron transport layer material is selected from any one of the compounds represented by the following structural formulas:

7. A method for preparing the electron transport layer material according to claim 1, characterized in that: The method specifically comprises the following steps: Step 1 specifically includes the following processes: Add raw material A (1.0 eq), bipyraclostrobin (1.0-2.0 eq) and potassium acetate (2.0-4.0 eq) into a three-necked flask, then add 1,4-dioxane, add tri(dibenzylideneacetone)dipalladium (0.02-0.10 eq) and X-Phos (0.1-0.2 eq) under N2, raise the temperature to 110-120° C., and reflux for 4-24 h; detect the reaction by thin layer chromatography, after the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and separation, retain the organic phase and concentrate, and purify by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8) to obtain intermediate 1; Step 2 Specific The process includes: Add intermediate 1 (1.0 eq) and raw material B (1.0-1.2 eq) to a three-necked flask, then add a mixed solution of toluene, ethanol and water (V:V:V=3:1:1), add 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) under N2, heat to 85°C-95°C, and reflux for 2-24 hours; detect the reaction by thin layer chromatography, after the reaction is completed, slightly lower the temperature, add dichloromethane and water for extraction and separation, retain the organic phase and concentrate, and purify by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8) to obtain chemical formula I; The specific synthetic route is as follows: In the above formula, X, Y, Z1-Z3, R1, n1, L, Ar1, Ar2 are as defined in the above chemical formula I; Hal1 and Hal2 independently represent Br and Cl.

8. An application of an electron transport layer material, characterized in that: The electron transport layer material according to any one of claims 1 to 6 is applied to an organic electroluminescent device.

9. The use according to claim 8, characterized in that: The organic electroluminescent device comprises an organic layer; the organic layer contains the electron transport layer material.

Images