A polycyclic aromatic organic electroluminescent compound and its preparation method and application

Abstract

The present invention belongs to the field of organic electroluminescent materials, and discloses a polycyclic aromatic organic electroluminescent compound and a preparation method and application thereof. The polycyclic aromatic organic electroluminescent compound provided by the present invention can be used as a hole transport material for an organic electroluminescent device, and after being used in an organic electroluminescent device, the driving voltage of the device can be reduced, the luminous efficiency of the device can be improved, and the service life of the device can be extended.

Description

Technical Field

[0001] The invention belongs to the field of organic electroluminescent materials, and in particular relates to a polycyclic aromatic organic electroluminescent compound and a preparation method and application thereof. Background Art

[0002] Organic light-emitting diode (OLED) is a very important electroluminescent device, which has the advantages of active light emission without backlight, high luminous efficiency, large viewing angle, fast response speed, low energy consumption, lighter and thinner, flexible display, etc. Organic electroluminescent elements use the recombination energy of holes injected from the anode and electrons injected from the cathode to make fluorescent substances emit light by applying an electric field. And the organic electroluminescent element has an anode, a cathode and an organic material layer between the two.

[0003] In order to improve the luminous efficiency and stability of organic electroluminescent elements, the organic material layer generally includes multiple layers with different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer, an electron transport layer (ETL) and an electron injection layer (EIL). In such an organic light-emitting element, when a voltage is applied between the anode and the cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the generated excitons generate light with a specific wavelength when they migrate to the ground state. Among them, the hole transport layer has the function of changing the hole transfer efficiency, luminous efficiency, life, etc. of holes to the light-emitting layer.

[0004] Although the hole transport materials currently used can improve the hole transport efficiency, luminous efficiency, device stability, etc., their service life still needs to be improved. Therefore, it is necessary to develop a hole transport material with a new structure to improve the shortcomings of the organic electroluminescent element in service life, which has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention discloses a polycyclic aromatic organic electroluminescent compound and a preparation method and application thereof. The device prepared from the polycyclic aromatic organic electroluminescent compound provided by the present invention has low driving voltage, high luminous efficiency and long service life.

[0006] In order to achieve the above objectives, the first objective of the present invention is to provide a polycyclic aromatic organic electroluminescent compound. The following technical scheme is adopted:

[0007] A polycyclic aromatic organic electroluminescent compound having a structure of formula I:

[0008]

[0009] In Formula I:

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

[0011] Ar1, Ar2, Ar3, and Ar4 are independently selected from substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, and their heteroatoms contain at least one of O, S, N, Si, and Se;

[0012] m, n are selected from 0 or 1, and m+n=1;

[0013] L1 and L2 are independently selected from a single bond, a substituted or unsubstituted C6-C12 aryl group.

[0014] Further, Formula I has the following structure of Formula I-1-I-4:

[0015]

[0016] Further, Ar1, Ar2, Ar3, and Ar4 are independently selected from substituted or unsubstituted C6-C24 aryl groups, substituted or unsubstituted C6-C15 heteroaryl groups, and their heteroatoms contain at least one of O, S, N, Si, and Se;

[0017] L1 and L2 are independently selected from a single bond, a substituted or unsubstituted phenyl group.

[0018] Furthermore, Ar1, Ar2, Ar3, and Ar4 can be connected to the following groups at any position:

[0019]

[0020] In the above formula, the hydrogen on the substituent can be further independently replaced partially or completely by deuterium; * indicates the position of the group connection.

[0021] The number of carbon atoms of the aryl and heteroaryl groups in the terms "substituted or unsubstituted C6-C30 aryl", "substituted or unsubstituted C6-C24 aryl", "substituted or unsubstituted C6-C12 aryl", "substituted or unsubstituted C6-C30 heteroaryl" and "substituted or unsubstituted C6-C15 heteroaryl" means the number of carbon atoms constituting the unsubstituted aryl group, the unsubstituted alkyl group or the total number of heteroatoms and carbon atoms constituting the heteroaryl group, without taking into account the number of carbon atoms in the substituents.

[0022] The term "substituted" means substituted by one, two or more substituents selected from the group consisting of hydrogen, deuterium, a halogen group, a cyano group, a trifluoromethyl group, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a butyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group, a 1-methylbutyl group, a 1-ethylbutyl group, a pentyl group, a n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, a n-hexyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 4-methyl-2-pentyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, a 1-methylhexyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a thienyl group, a furanyl group, a pyrrolyl group, a benzothienyl group, a benzofuranyl group, a pyridyl group, an indolyl group, a cyclopentanyl group, a cyclohexanyl group, and an adamantane group, or substituted by two or more of the substituents shown above connected to each other, or having no substituents.

[0023] Preferably, the polycyclic aromatic organic light-emitting compound is selected from any one of the following compounds:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032] The second object of the present invention is to provide a method for preparing the polycyclic aromatic organic electroluminescent compound as described above, the specific operation is as follows:

[0033]

[0034] wherein X, Ar1, Ar2, Ar3, Ar4, m, n, L1, and L2 are as defined in Formula I above, and X1-X2 are selected from halogen (e.g., F, Cl, Br or I).

[0035] Step 1 specifically comprises the following steps: under a nitrogen environment, adding raw material A and raw material B to a mixed solution of toluene, ethanol and water, adding potassium carbonate and tetrakis(triphenylphosphine)palladium thereto, stirring evenly, heating to 70°C-90°C, and reflux reaction for 4-12h, detecting the reaction by thin layer chromatography, and after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with dichloromethane; combining the organic phases and concentrating them, using a mixed solution of dichloromethane and petroleum ether as an eluent, and purifying by column chromatography to obtain intermediate 1;

[0036] Step 2 specifically comprises the following steps: cooling to -70°C to -80°C to dissolve the intermediate 1 in THF, slowly adding n-butyl lithium to the solution of the intermediate 1, reacting for 2-4 hours, slowly adding the solution of the raw material C to the reaction bottle, warming to room temperature, continuing to react for 4-12 hours, detecting the reaction by thin layer chromatography, washing with water three times after the reaction is completed, retaining the organic phase, then extracting the aqueous phase with dichloromethane, combining the organic phases and concentrating them, using a mixed solution of dichloromethane and petroleum as an eluent, and purifying by column chromatography to obtain the intermediate 2;

[0037] Step 3 specifically includes the following steps: dissolving intermediate 2 in DCM, stirring and dissolving at room temperature, then adding methanesulfonic acid thereto, reacting at room temperature for 2-4 hours, detecting the reaction by thin layer chromatography, washing with water three times after the reaction is completed, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator; using a small amount of dichloromethane to completely dissolve the solid organic matter, and then slowly adding dropwise to the petroleum ether solution, stirring evenly, precipitating, filtering to obtain a solid, eluting with anhydrous ethanol and petroleum ether in turn, and drying, thereby obtaining intermediate 3;

[0038] Step 4 specifically comprises the following steps: under a nitrogen environment, dissolving the intermediate 3 in a mixed solution of toluene, ethanol and water, dissolving the raw material D in a mixed solution of toluene, ethanol and water, slowly adding the raw material D solution to the intermediate 3 solution, adding potassium carbonate and tetrakis(triphenylphosphine)palladium thereto, stirring evenly, heating to 70°C-90°C, and reflux reaction for 4-12h, detecting the reaction by thin layer chromatography, and after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with dichloromethane; combining the organic phases and concentrating, using a mixed solution of dichloromethane and petroleum ether as an eluent, and purifying by column chromatography to obtain the intermediate 4;

[0039] Step 5 specifically includes the following steps: under a nitrogen environment, dissolving intermediate 4 in toluene, dissolving raw material E in toluene, then slowly adding raw material E to the intermediate 4 solution, adding tri(dibenzylideneacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyl alcohol thereto, heating to 100°C-120°C, reacting for 4-10 hours, after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing three times with water, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator, dissolving in petroleum ether / ethanol, recrystallizing, filtering, rinsing the filter cake with petroleum ether several times, and drying in a 60°C oven for 5 hours to obtain chemical formula I.

[0040] The third object of the present invention is to provide an application of a polycyclic aromatic organic electroluminescent compound. The polycyclic aromatic organic electroluminescent compound as described above is applied to an organic electroluminescent device.

[0041] In another aspect, the present invention provides an organic electroluminescent device, comprising an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, wherein the organic thin film layer comprises the polycyclic aromatic organic electroluminescent compound as described above.

[0042] Preferably, the organic thin film layer comprises a light-emitting layer, and the light-emitting layer comprises a host material and a doping material.

[0043] Preferably, the organic thin film layer further comprises at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer or an electron injection layer, and the hole transport material comprises the polycyclic aromatic organic electroluminescent compound as described above.

[0044] Compared with the prior art, the present invention provides a polycyclic aromatic organic electroluminescent compound and a preparation method and application thereof, which have the following beneficial effects:

[0045] The polycyclic aromatic compounds of the present invention introduce triarylamine on the basis of the parent core. When all the triarylamine groups are substituted with aromatic groups, the energy level is low, which avoids the localization of carrier migration and can reduce the hole transport energy barrier, thereby improving the migration rate and the luminous efficiency. The triarylamine has excellent hole transport performance. The triarylamine material is used as a hole transport layer, and a group with a high triplet energy level is introduced, which can reduce the energy difference between energy levels and greatly improve the life of the device. The device life and efficiency prepared by the doping material in the present invention are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0047] Figure 1 is the H NMR spectrum of compound 34.

[0048] Figure 2 This is the H NMR spectrum of compound 162. DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the related drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The invention specifically discloses a polycyclic aromatic organic electroluminescent compound and a preparation method and application thereof.

[0051] A series of palladium-catalyzed coupling reactions carried out in the present invention utilize the difference that the activity of Br is greater than that of Cl on the one hand, and on the other hand, the reaction site is controlled by controlling the reaction conditions, and the reaction is purified by column chromatography or silica gel funnel to remove by-products to obtain the target compound.

[0052] Reference to common knowledge is as follows:

[0053] "Transition Metal Organic Chemistry" (Original Sixth Edition), Robert H. Crabtree, Publisher: Shanghai East China University of Science and Technology Press, Publication Date: 2017-09-00, ISBN: 978-7-5628-5111-0, page 388.

[0054] "Organic Chemistry and Optoelectronic Materials Experimental Tutorial", Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0055] The specific embodiments described below are only part of the embodiments of the present application, rather than all the embodiments.

[0056] In addition, it should be noted that the numerical values ​​given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0057] Embodiment 1:

[0058]

[0059] Step 1 specifically includes the following steps: under a nitrogen environment, raw material A-103 (1.0 eq) (CAS number: 1388041-06-2) and raw material B-103 (1.0 eq) (CAS number: 244205-40-1) are added to a mixed solution of toluene, ethanol and water, potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added thereto, stirred evenly, heated to 85°C, and refluxed for 4 hours, and the reaction is detected by thin layer chromatography. After the reaction is completed, the temperature is slightly lowered, and diatomaceous earth is used for filtering to remove salt and catalyst. After the filtrate is cooled to room temperature, it is washed with water three times, the organic phase is retained, and then the aqueous phase is extracted with dichloromethane; the organic phases are combined and concentrated, and a mixed solution of dichloromethane and petroleum ether is used as an eluent, and the intermediate 1 is purified by column chromatography (yield: 71.6%).

[0060] Step 2 specifically includes the following steps: cooling to -78°C to dissolve intermediate 1 (1.3 eq) in THF, ventilating 3 times, stirring for 10 minutes, slowly adding n-butyl lithium (1.2 eq) to the solution of intermediate 1 (1.3 eq), reacting for 2 hours, slowly adding the raw material C-103 (1.0 eq) (CAS No.: 119-61-9) solution to the reaction bottle, warming to room temperature, and continuing to react for 8 hours. The reaction is detected by thin layer chromatography. After the reaction is completed, wash three times with water, retain the organic phase, then extract the aqueous phase with dichloromethane, combine the organic phases and concentrate, use a mixed solution of dichloromethane and petroleum as eluent, and purify by column chromatography to obtain intermediate 2 (yield: 43.5%).

[0061] Step 3 specifically includes the following steps: dissolving intermediate 2 (1.0 eq) in DCM, stirring and dissolving at room temperature, then adding methanesulfonic acid (3.0 eq) thereto, reacting at room temperature for 4 h, detecting the reaction by thin layer chromatography, and after the reaction is completed, washing three times with water, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator; using a small amount of dichloromethane to completely dissolve the solid organic matter, and then slowly adding dropwise to the petroleum ether solution, stirring evenly, a precipitate is precipitated, and the solid is filtered out, and it is sequentially rinsed with anhydrous ethanol and petroleum ether, and dried to obtain intermediate 3 (yield: 89.4%).

[0062] Step 4 specifically comprises the following steps: under a nitrogen environment, the intermediate 3 (1.0 eq) is dissolved in a mixed solution of toluene, ethanol and water, the raw material D-103 (1.0 eq) (CAS No.: 1679-18-1) is dissolved in a mixed solution of toluene, ethanol and water, the raw material D-103 (1.0 eq) (CAS No.: 1679-18-1) solution is slowly added to the intermediate 3 (1.0 eq) solution, potassium carbonate (2.2 eq) is added thereto, and the mixture is stirred for 2 hours. (Triphenylphosphine) palladium (0.01eq), stirred evenly, heated to 85°C, and refluxed for 8h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered and filtered using diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained and the aqueous phase was extracted with dichloromethane. The organic phases were combined and concentrated, and a mixed solution of dichloromethane and petroleum ether was used as an eluent. The intermediate 4 was purified by column chromatography (yield: 84.1%).

[0063] Step 5 specifically comprises the following steps: under a nitrogen environment, the intermediate 4 (1.0 eq) is dissolved in toluene, the raw material E-103 (1.0 eq) (CAS No.: 32228-99-2) is dissolved in toluene, and then the raw material E-103 (1.0 eq) (CAS No.: 32228-99-2) is slowly added to the intermediate 4 (1.0 eq) solution, tri(dibenzylideneacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butyl alcohol (2.0 eq) are added thereto, the temperature is raised to 110°C, and the reaction is carried out. The reaction mixture was stirred for 4 hours. After the reaction was completed, the temperature was slightly lowered and filtered through diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and dried over anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator and dissolved in petroleum ether / ethanol for recrystallization and filtration. The filter cake was rinsed with petroleum ether several times and dried in an oven at 60°C for 5 hours to obtain compound 34 (yield: 84.2%, MS (ESI, m / Z): [M+H]+=677.46).

[0064] The obtained compound 34 was tested and analyzed, and the results were as follows:

[0065] HPLC purity: >99.95%.

[0066] Elemental Analysis:

[0067] The test values ​​are: C, 90.23; H, 5.27; N, 2.18; O, 2.43.

[0068] Embodiment 2:

[0069]

[0070] Step 1 specifically includes the following steps: under a nitrogen environment, raw material A-312 (1.0 eq) (CAS number: 7342-82-7) and raw material B-312 (1.0 eq) (CAS number: 244205-40-1) are added to a mixed solution of toluene, ethanol and water, potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) are added thereto, stirred evenly, heated to 85°C, and refluxed for 5 hours, and the reaction is detected by thin layer chromatography. After the reaction is completed, the temperature is slightly lowered, and diatomaceous earth is used for filtering to remove salt and catalyst. After the filtrate is cooled to room temperature, it is washed three times with water, the organic phase is retained, and then the aqueous phase is extracted with dichloromethane; the organic phases are combined and concentrated, and a mixed solution of dichloromethane and petroleum ether is used as an eluent, and the intermediate 1 is purified by column chromatography (yield: 80.4%).

[0071] Step 2 specifically includes the following steps: cooling to -78°C to dissolve intermediate 1 (1.0 eq) in THF, ventilating 3 times, stirring for 10 minutes, slowly adding n-butyl lithium (1.2 eq) to the solution of intermediate 1 (1.0 eq), reacting for 2 hours, slowly adding the raw material C-312 (1.0 eq) (CAS No.: 142395-18-4) solution to the reaction bottle, warming to room temperature, and continuing to react for 8 hours. The reaction is detected by thin layer chromatography. After the reaction is completed, wash three times with water, retain the organic phase, then extract the aqueous phase with dichloromethane, combine the organic phases and concentrate, use a mixed solution of dichloromethane and petroleum as eluent, and purify by column chromatography to obtain intermediate 2 (yield: 73.3%).

[0072] Step 3 specifically includes the following steps: dissolving intermediate 2 (1.0 eq) in DCM, stirring and dissolving at room temperature, then adding methanesulfonic acid (3.0 eq) thereto, reacting at room temperature for 4 hours, detecting the reaction by thin layer chromatography, and after the reaction is completed, washing three times with water, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator; using a small amount of dichloromethane to completely dissolve the solid organic matter, and then slowly adding it dropwise to the petroleum ether solution, stirring evenly, a precipitate is precipitated, and the solid is filtered out, and it is sequentially rinsed with anhydrous ethanol and petroleum ether, and dried to obtain intermediate 3 (yield: 93.1%).

[0073] Step 4 specifically includes the following steps: Under a nitrogen environment, the intermediate 3 (1.0 eq) is dissolved in toluene, the raw material D-312 (1.0 eq) (CAS No.: 32228-99-2) is dissolved in toluene, and then the raw material D-312 (1.0 eq) (CAS No.: 32228-99-2) is slowly added to the intermediate 3 (1.0 eq) solution, tri(dibenzylideneacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butyl alcohol (2.0 eq) are added thereto, and the temperature is raised to 110° C. for reaction. 4h. After the reaction, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. After the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator and dissolved in petroleum ether / ethanol for recrystallization and filtration. The filter cake was rinsed with petroleum ether several times and dried in a 60°C oven for 5h to obtain compound 162 (yield: 86.6%, MS (ESI, m / Z): [M+H]+=617.41).

[0074] The obtained compound 162 was tested and analyzed, and the results were as follows:

[0075] HPLC purity: >99.95%.

[0076] Elemental Analysis:

[0077] The test values ​​are: C, 87.24; H, 5.18; N, 2.38; S, 5.31.

[0078] The following compounds were synthesized by referring to the synthesis methods of Examples 1 to 2, and tested using a Waters XEVOTQD mass spectrometer, which has low precision, and tested using an ESI source. The mass spectrometry test values ​​are shown in Table 1 below:

[0079] Table 1

[0080]

[0081]

[0082] The organic electroluminescent device prepared by the hole transport material provided in the above embodiment includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode.

[0083] When the organic layer includes a hole transport layer, the hole transport layer includes the hole transport material provided in the above embodiment.

[0084] Specifically, the steps for preparing the organic electroluminescent device are as follows:

[0085] Device Example 1:

[0086] a. ITO anode: Wash the ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm in distilled water twice, ultrasonically wash for 30 minutes, and then repeatedly wash it with distilled water twice, ultrasonically wash for 10 minutes. After washing, transfer it to a spin dryer for drying, and finally bake it in a vacuum oven at 220℃ for 2 hours. After baking, cool it down and it can be used. Use this substrate as the anode, use an evaporation machine to carry out the evaporation device process, and evaporate other functional layers on it in sequence.

[0087] b. HIL (hole injection layer): The evaporation rate is 97:3, and the compound 3 and P-dopant provided in the above embodiment are vacuum-evaporated as hole injection layer materials, and the evaporation rate ratio of the compound 3 and P-dopant is 10 nm;

[0088] c. HTL (hole transport layer): At a deposition rate of , 130 nm of the compound 3 provided in the above embodiment is vacuum-deposited on the hole injection layer as a hole transport layer;

[0089] d. EBL (electron blocking layer): At a deposition rate of 10 nm, EB-1 was vacuum-deposited on the hole transport layer as an electron blocking layer.

[0090] e. EML (luminescent layer): The host material (Host) and the dopant material (Dopant) with a thickness of 20 nm are vacuum evaporated on the electron blocking layer as the light-emitting layer, wherein the evaporation rate ratio of Host to Dopant is 97:3.

[0091] f. HBL (hole blocking layer): At a deposition rate of , 5 nm of HB-1 was vacuum-deposited on the light-emitting layer as a hole blocking layer;

[0092] g. ETL (Electron Transport Layer): At a deposition rate of , 30 nm of ET-1 was vacuum-deposited on the hole blocking layer as an electron transport layer;

[0093] h. EIL (electron injection layer): The evaporation rate is 1.0 nm, and a Yb film layer is evaporated to form an electron injection layer;

[0094] i. Cathode: 18 nm of magnesium and silver were evaporated at a deposition rate ratio of 1:9 to obtain an OLED device;

[0095] j. Light extraction layer: At a deposition rate of , CPL with a thickness of 70 nm was vacuum-deposited on the cathode as a light extraction layer.

[0096] Then the vapor-deposited substrate is packaged. First, the cleaned cover is coated with UV glue using glue coating equipment, and then the coated cover is moved to the pressing section, the vapor-deposited substrate is placed on the upper end of the cover, and finally the substrate and cover are bonded by bonding equipment, and the UV glue is cured by light.

[0097] The required material structure is as follows:

[0098]

[0099] Device Example 2-31:

[0100] Device Example 2-Device Example 31 Referring to the above method, the compound 3 used in Device Example 1 is replaced by compounds 5, 8, 12, 15, 20, 23, 27, 29, 34, 36, 40, 47, 56, 63, 70, 76, 88, 95, 102, 111, 118, 128, 135, 142, 148, 155, 162, 171, 181 and 192 as hole transport layers to prepare corresponding organic electroluminescent devices.

[0101] Device Comparison Examples 1-6:

[0102] The only difference between the preparation method of the organic electroluminescent device provided in the device comparison example and the device example 1 is that the organic electroluminescent device uses the existing comparative compound af to replace the hole transport material (compound 3) in the above device example 1 for evaporation to prepare the corresponding organic electroluminescent device, which is recorded as device comparison examples 1-6.

[0103] Among them, the chemical structure formula of the comparative compound af is as follows:

[0104]

[0105] The driving voltage, luminous efficiency, BI value and life of the organic electroluminescent devices obtained from the above device embodiments 1-31 and device comparative examples 1-6 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below:

[0106] Table 2

[0107]

[0108]

[0109] According to the above table, the organic electroluminescent device prepared by using the compound provided by the present invention as the hole transport material has a slightly lower driving voltage, an improved luminous efficiency, and a lifespan increased by 35-90h compared with the organic electroluminescent device prepared by using the comparative compounds 1-6 as the hole transport material.

[0110] The applicant declares that the present invention illustrates the compounds and applications of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by 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 polycyclic aromatic organic electroluminescent compound, characterized in that: The structure of the polycyclic aromatic compound is shown in Formula I: In formula Ⅰ; X is independently selected from O, S; Ar1, Ar2, Ar3, and Ar4 are independently selected from substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, and their heteroatoms contain at least one of O, S, N, Si, and Se; m, n are selected from 0 or 1, and m+n=1; L1 and L2 are independently selected from a single bond, a substituted or unsubstituted C6-C12 aryl group.

2. A polycyclic aromatic organic electroluminescent compound according to claim 1, characterized in that: Formula I has the following structures:

3. The polycyclic aromatic organic electroluminescent compound according to claim 1 or 2, characterized in that: Ar1, Ar2, Ar3, and Ar4 are independently selected from substituted or unsubstituted C6-C24 aryl groups, substituted or unsubstituted C6-C15 heteroaryl groups, and their heteroatoms contain at least one of O, S, N, Si, and Se. L1 and L2 are independently selected from a single bond, a substituted or unsubstituted phenyl group; 4. The polycyclic aromatic organic electroluminescent compound according to claim 1 or 2, characterized in that: Ar1, Ar2, Ar3, Ar4 can be connected to the following groups at any position: In the above formula, the hydrogen on the substituent can be further independently replaced partially or completely by deuterium; * indicates the position of the group connection.

5. The hole-based organic electroluminescent compound according to claim 1, characterized in that: The structure of the polycyclic aromatic organic electroluminescent compound includes but is not limited to any one of the following compounds:

6. A method for preparing a polycyclic aromatic organic electroluminescent compound as claimed in claim 1, characterized in that: The method operates as follows: Step 1 specifically comprises the following steps: under a nitrogen environment, adding raw material A and raw material B to a mixed solution of toluene, ethanol and water, adding potassium carbonate and tetrakis(triphenylphosphine)palladium thereto, stirring evenly, heating to 70°C-90°C, and reflux reaction for 4-12h, detecting the reaction by thin layer chromatography, and after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with dichloromethane; combining the organic phases and concentrating them, using a mixed solution of dichloromethane and petroleum ether as an eluent, and purifying by column chromatography to obtain intermediate 1; Step 2 specifically comprises the following steps: cooling to -70°C to -80°C to dissolve the intermediate 1 in THF, slowly adding n-butyl lithium to the solution of the intermediate 1, reacting for 2-4 hours, slowly adding the solution of the raw material C to the reaction bottle, warming to room temperature, continuing to react for 4-12 hours, detecting the reaction by thin layer chromatography, washing with water three times after the reaction is completed, retaining the organic phase, then extracting the aqueous phase with dichloromethane, combining the organic phases and concentrating them, using a mixed solution of dichloromethane and petroleum as an eluent, and purifying by column chromatography to obtain the intermediate 2; Step 3 specifically includes the following steps: dissolving intermediate 2 in DCM, stirring and dissolving at room temperature, then adding methanesulfonic acid thereto, reacting at room temperature for 2-4 hours, detecting the reaction by thin layer chromatography, washing with water three times after the reaction is completed, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator; using a small amount of dichloromethane to completely dissolve the solid organic matter, and then slowly adding dropwise to the petroleum ether solution, stirring evenly, precipitating, filtering to obtain a solid, eluting with anhydrous ethanol and petroleum ether in turn, and drying, thereby obtaining intermediate 3; Step 4 specifically comprises the following steps: under a nitrogen environment, dissolving the intermediate 3 in a mixed solution of toluene, ethanol and water, dissolving the raw material D in a mixed solution of toluene, ethanol and water, slowly adding the raw material D solution to the intermediate 3 solution, adding potassium carbonate and tetrakis(triphenylphosphine)palladium thereto, stirring evenly, heating to 70°C-90°C, and reflux reaction for 4-12h, detecting the reaction by thin layer chromatography, and after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with dichloromethane; combining the organic phases and concentrating, using a mixed solution of dichloromethane and petroleum ether as an eluent, and purifying by column chromatography to obtain the intermediate 4; Step 5 specifically includes the following steps: under a nitrogen environment, dissolving intermediate 4 in toluene, dissolving raw material E in toluene, then slowly adding raw material E to the intermediate 4 solution, adding tri(dibenzylideneacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butyl alcohol thereto, heating to 100°C-120°C, reacting for 4-10h, after the reaction is completed, slightly lowering the temperature, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, removing the solvent with a rotary evaporator, dissolving in petroleum ether / ethanol, recrystallizing, filtering, rinsing the filter cake with petroleum ether for multiple times, and drying in a 60°C oven for 5h to obtain chemical formula I; The specific synthetic route is as follows: wherein X, Ar1, Ar2, Ar3, Ar4, m, n, L1, and L2 are as defined in Formula I above, and X1-X2 are selected from halogen (e.g., F, Cl, Br or I).

7. An application of a polycyclic aromatic organic electroluminescent compound, characterized in that: The polycyclic aromatic organic electroluminescent compound as claimed in claim 1 is used in an organic electroluminescent device.

8. The use according to claim 7, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and at least one organic layer disposed between the first electrode and the second electrode; the organic layer comprises the polycyclic aromatic organic electroluminescent compound as claimed in claim 1.

9. The use according to claim 8, characterized in that: The polycyclic aromatic organic electroluminescent compound is used as a hole transport material of an organic electroluminescent device.

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