An organic electroluminescent compound and its preparation method and application

Abstract

The invention discloses an organic electroluminescent compound and a preparation method and application thereof. The molecular formula of the compound is shown in the general formula (I): #imgabs0# The compound uses benzonaphthofuran as a skeleton to connect with an aromatic amine group. The benzonaphthofuran has a rigid planar structure, and the symmetry of the molecule is further reduced by connecting an aromatic group, a cycloalkyl group, etc., and the conformational isomers of the molecule are increased, so that the compound is not easy to crystallize and not easy to aggregate, and has good film-forming property and thermal stability and a high glass transition temperature; the aromatic amine group makes it have a strong hole transmission ability, and the mono-triarylamine structure can reduce the crystallinity of the molecule, reduce the planarity of the molecule, and prevent the molecule from moving on the plane. At the same time, the high hole transmission rate can reduce the driving voltage of the device and improve the efficiency and life of the organic electroluminescent device.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and relates to an organic electroluminescent compound and a preparation method and application thereof. Background Art

[0002] In the prior art, organic electroluminescent (OLED) device technology can be used to manufacture both display products and lighting products, and is expected to replace existing liquid crystal displays and fluorescent lighting, with a wide range of applications. Organic electrical components that utilize organic light-emitting phenomena usually have an anode, a cathode, and an organic layer therebetween. In order to improve the efficiency and stability of organic electrical components, the organic layer is usually composed of a multilayer structure composed of various different substances.

[0003] In this organic light emitting diode, 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. The generated excitons generate light with a specific wavelength when they migrate to the ground state. It has the following structure: an anode, a cathode, and an organic material layer between the two. In order to improve the efficiency and stability of the organic EL element, the organic material layer 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). Among them, layers with the function of transporting holes, such as a hole injection layer, a hole transport layer, an electron blocking layer, etc., can change the hole transfer efficiency, luminous efficiency, life, etc. of holes to the light emitting layer, which has a huge impact on the performance data of the electronic device.

[0004] In order to improve the luminous efficiency and lifespan, a luminescent auxiliary layer is usually added between the hole transport layer and the light-emitting layer (i.e., a multi-layer hole transport layer is set) to improve the device lifespan and efficiency. The luminescent auxiliary layer can reduce the potential barrier between the hole transport layer and the light-emitting layer, reduce the driving voltage of the organic electroluminescent device, and further increase the utilization rate of holes, thereby improving the luminous efficiency and lifespan of the device and reducing the driving voltage. However, there are few functional materials that can form luminescent auxiliary layers. In particular, the lifespan and luminous efficiency of OLEDs are not significantly improved, and the glass transition temperature is low. Therefore, it is particularly important to develop higher performance organic functional materials to meet the requirements of panel manufacturers. Summary of the invention

[0005] One of the purposes of the present invention is to provide a novel organic electroluminescent compound.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] An organic electroluminescent compound, the molecular formula of which is shown in general formula (I):

[0008]

[0009] Ar1 is a benzene ring, and is fused with the adjacent benzene ring of dibenzofuran;

[0010] Ar2 is a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30 membered heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen and sulfur;

[0011] R1 is selected from substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30 membered heterocycloalkyl, whose heteroatoms are selected from oxygen, nitrogen and sulfur; substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-30 membered heteroaryl, whose heteroatoms are selected from oxygen, nitrogen and sulfur;

[0012] R2-R5 are each independently selected from hydrogen, deuterium, a halogen group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted 3-30 membered heterocycloalkyl group, wherein the heteroatoms are selected from oxygen, nitrogen and sulfur; a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30 membered heteroaryl group, wherein the heteroatoms are selected from oxygen, nitrogen and sulfur.

[0013] In the present specification, "substituted" means substituted by one, two or more substituents selected from the following: C1-C20 alkyl, C1-C20 alkoxy, C6-C30 aryl, C6-C30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen and sulfur.

[0014] Furthermore, the molecular formula of the organic electroluminescent compound is as shown in general formula (II-1)-(II-3):

[0015]

[0016] Furthermore, the R1 is selected from the following structural formula:

[0017]

[0018] In the above formula, * represents a connection point.

[0019] Furthermore, the molecular formula of the above organic electroluminescent compound is as shown in general formula (III-1)-(III-15):

[0020]

[0021] Further, the Ar2 is selected from the following structural formula:

[0022]

[0023] Wherein, R6 is selected from substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted 3-18 membered heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, sulfur, substituted or unsubstituted C1-C18 alkyl; in the above formula, * represents the connection point.

[0024] Furthermore, R2-R5 are each independently selected from hydrogen, deuterium, a halogen group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, wherein the heteroatoms are selected from oxygen, nitrogen and sulfur; a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted 3-20-membered heteroaryl group, wherein the heteroatoms are selected from oxygen, nitrogen and sulfur.

[0025] Furthermore, the general formula 1 is represented by any one of the following formulas (1)-(126):

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035] The second object of the present invention is to provide a method for preparing the above-mentioned organic electroluminescent compound, which adopts the following technical scheme:

[0036] A method for preparing an organic electroluminescent compound comprises the following steps:

[0037] (1) After raw materials A and B are dissolved in an organic solvent, Pd2(dba)3, P(t-Bu)3 and t-BuONa are added under a N2 atmosphere, the temperature is raised to 110-120°C and stirred for reaction for 10-12h. After the reaction is completed, the mixture is filtered, washed, dried, evaporated and purified to obtain the compound shown in Intermediate 1;

[0038] (2) Under N2 protection, the intermediate 1, raw material C, Pd2(dba)3, P(t-Bu)3 and t-BuONa are heated to 110-120°C and stirred for reaction for 12-14 hours. After the reaction, the mixture is filtered, washed, dried, evaporated and purified to obtain a compound of formula 1;

[0039] The specific synthetic route is shown in Reaction Scheme 1:

[0040]

[0041] wherein R1 to R5, Ar1 and Ar2 have the same meanings as given above.

[0042] Furthermore, a method for preparing an organic electroluminescent compound comprises the following steps:

[0043] After raw material A and raw material B are dissolved in toluene, Pd2(dba)3, P(t-Bu)3 and t-BuONa are added under N2 atmosphere, the temperature is raised to 110-120°C and stirred for reaction for 10-12h. After the reaction is completed, diatomaceous earth is used for hot filtration to remove salt and catalyst. After the filtrate is cooled to room temperature, distilled water is added to the filtrate for washing. After separation, the organic phase is retained, the aqueous phase is extracted with ethyl acetate, and then the combined organic layer is dried with magnesium sulfate, and the solvent is removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether is used as an eluent, and the remaining substance is purified by column chromatography to obtain the compound shown in Intermediate 1;

[0044] Under N2 protection, the intermediate 1, raw material C, Pd2(dba)3, P(t-Bu)3 and t-BuONa are heated to 110-120°C and stirred for reaction for 12-14 hours. After the reaction is completed, diatomaceous earth is used for hot filtration to remove salt and catalyst. After the filtrate is cooled to room temperature, distilled water is added to the filtrate for washing. After separation, the organic phase is retained, the aqueous phase is extracted with ethyl acetate, and then the combined organic layer is dried with magnesium sulfate, and the solvent is removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether is used as an eluent, and the remaining substance is purified by column chromatography to obtain a compound represented by general formula 1.

[0045] The third object of the present invention is to provide a use of the above organic electroluminescent compound in the preparation of an organic light-emitting device or a fluorescent lamp.

[0046] A fourth object of the present invention is to provide an organic electroluminescent device, comprising a first electrode, a second electrode, and one or more organic layers disposed between the first electrode and the second electrode; and

[0047] The organic layer includes a light-emitting auxiliary layer, and also includes one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a light extraction layer and a capping layer; and,

[0048] The light-emitting auxiliary layer comprises one or more organic electroluminescent compounds as described above.

[0049] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0050] The present invention provides an organic electroluminescent compound for a blue light emitting auxiliary layer having excellent performance, which is obtained by connecting benzonaphthofuran as a skeleton with an aromatic amine group. The prepared device has the characteristics of high luminous efficiency, low driving voltage and long service life.

[0051] The aromatic amine group in the compound of the present invention enables it to have a strong hole transport ability. The mono-triarylamine structure can reduce the crystallinity of the molecule, reduce the planarity of the molecule, and prevent the molecule from moving on the plane. At the same time, the high hole transport rate can reduce the driving voltage of the device and improve the efficiency and life of the organic electroluminescent device.

[0052] Benzonaphthofuran has a rigid planar structure, and by connecting aromatic groups, cycloalkyl groups, etc., the symmetry of the molecule is further reduced, the conformational isomers of the molecule are increased, and the compound is not easy to crystallize or aggregate. It has good film-forming properties, thermal stability and a high glass transition temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] Figure 1 It is the hydrogen nuclear magnetic resonance spectrum of compound 11 prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0056] In Examples 1-4, the raw material A is obtained by the following two-step reaction:

[0057]

[0058] The raw material 1 (1 eq) was dissolved in a dichloromethane solution, and liquid bromine (1.1 eq) was slowly added and stirred at room temperature for 4 hours. After the reaction of the raw material was completed, the reaction was stopped by TLC monitoring, and a saturated sodium thiosulfate solution was added for quenching. The liquids were separated, and the organic phase was retained. The solvent was removed by a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:12) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in the intermediate 1-1;

[0059] The intermediate 1-1 (1 eq) and the raw material 2 (1 eq) are dissolved in a mixed solution of toluene ethanol and water, and then ventilated 3 times. Potassium carbonate and tetrakistriphenylphosphine palladium catalyst are added under nitrogen protection, stirred evenly, heated to 90°C, and refluxed for 6 hours; after the reaction is completed, the temperature is slightly lowered, diatomaceous earth is used for filtering, salt and catalyst are removed, and the filtrate is cooled to room temperature, washed three times with water, the organic phase is retained, and then the aqueous phase is extracted with ethyl acetate; after the organic phases are combined, anhydrous magnesium sulfate is used for drying, and a rotary evaporator is used to remove the solvent to obtain solid organic matter. A small amount of dichloromethane is used to completely dissolve the solid organic matter, and then it is slowly added dropwise to a petroleum ether solution, stirred evenly, and a precipitate is precipitated. The solid is filtered to obtain a solid, and it is rinsed with anhydrous ethanol and petroleum ether in turn, and dried to obtain raw material A.

[0060] Example 1

[0061]

[0062] After raw material A (40.00 mmol) and raw material B (40.00 mmol) were dissolved in toluene, Pd2(dba)3 (0.40 mmol), P(t-Bu)3 (2.00 mmol) and t-BuONa (80.00 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and stirred for reaction for 12 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:14) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in Intermediate 1 (10.70 g, yield: 69.47%);

[0063] After the intermediate 1 (27.75 mmol) and the raw material C (27.75 mmol) were dissolved in toluene, Pd2(dba)3 (0.27 mmol), P(t-Bu)3 (1.38 mmol) and t-BuONa (55.50 mmol) were added under a N2 atmosphere, the temperature was raised to 120°C and the reaction was stirred for 14 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:8) was used as an eluent, and the remaining substance was purified by column chromatography to obtain compound 1 (13.91 g, yield: 71.35%, Mw: 702.86).

[0064] Mass spectrometry test: theoretical value is 702.86; tested value is 702.59.

[0065] Elemental Analysis:

[0066] Calculated values: C, 88.86; H, 4.88; N, 3.99; O, 2.28.

[0067] The test values ​​are: C, 88.54; H, 4.97; N, 4.12; O, 2.31.

[0068] Example 2

[0069]

[0070] After raw material A (40.00 mmol) and raw material B (40.00 mmol) were dissolved in toluene, Pd2(dba)3 (0.40 mmol), P(t-Bu)3 (2.00 mmol) and t-BuONa (80.00 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and stirred for reaction for 12 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:14) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in Intermediate 1 (16.71 g, yield: 81.68%);

[0071] After the intermediate 1 (32.66 mmol) and the raw material C (32.66 mmol) were dissolved in toluene, Pd2(dba)3 (0.32 mmol), P(t-Bu)3 (1.63 mmol) and t-BuONa (65.32 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and the reaction was stirred for 14 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:8) was used as an eluent, and the remaining substance was purified by column chromatography to obtain compound 11 (22.67 g, yield: 83.78%, Mw: 829.02).

[0072] Mass spectrometry test: theoretical value is 829.02; tested value is 828.88.

[0073] Elemental Analysis:

[0074] Calculated values: C, 89.83; H, 4.86; N, 3.38; O, 1.93.

[0075] The test values ​​are: C, 89.67; H, 4.59; N, 2.33; O, 2.18.

[0076] Example 3

[0077]

[0078] After raw material A (40.00 mmol) and raw material B (40.00 mmol) were dissolved in toluene, Pd2(dba)3 (0.40 mmol), P(t-Bu)3 (2.00 mmol) and t-BuONa (80.00 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and stirred for reaction for 12 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:14) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in Intermediate 1 (16.30 g, yield: 79.67%);

[0079] After intermediate 1 (31.85 mmol) and raw material C (31.85 mmol) were dissolved in toluene, Pd2(dba)3 (0.31 mmol), P(t-Bu)3 (1.59 mmol) and t-BuONa (63.16 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and the reaction was stirred for 14 hours. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:8) was used as an eluent, and the remaining substance was purified by column chromatography to obtain compound 53 (19.97 g, yield: 75.68%, Mw: 829.02).

[0080] Mass spectrometry test: theoretical value is 829.02; tested value is 828.92.

[0081] Elemental Analysis:

[0082] Calculated values: C, 89.83; H, 4.86; N, 3.38; O, 1.93.

[0083] The test values ​​are: C, 89.23; H, 5.29; N, 3.56; O, 2.21.

[0084] Example 4

[0085]

[0086] After raw material A (40.00 mmol) and raw material B (40.00 mmol) were dissolved in toluene, Pd2(dba)3 (0.40 mmol), P(t-Bu)3 (2.00 mmol) and t-BuONa (80.00 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and stirred for reaction for 12 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:14) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in Intermediate 1 (15.98 g, yield: 79.67%);

[0087] After the intermediate 1 (31.85 mmol) and the raw material C (31.85 mmol) were dissolved in toluene, Pd2(dba)3 (0.31 mmol), P(t-Bu)3 (1.59 mmol) and t-BuONa (63.16 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and the reaction was stirred for 14 hours. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:8) was used as an eluent, and the remaining substance was purified by column chromatography to obtain compound 61 (21.45 g, yield: 82.26%, Mw: 819.02).

[0088] Mass spectrometry test: theoretical value is 819.02; tested value is 819.23.

[0089] Elemental Analysis:

[0090] Calculated values: C, 89.46; H, 5.17; N, 3.42; O, 1.95.

[0091] The test values ​​are: C, 89.23; H, 5.29; N, 3.56; O, 2.21.

[0092] In Example 5, the raw material A needs to be obtained by the following two steps:

[0093]

[0094] The raw material 3 (1 eq) was dissolved in a chloroform solution, and then liquid bromine (1.1 eq) was slowly added and stirred at room temperature for 4 hours. After the reaction of the raw material was completed, the reaction was stopped by TLC monitoring, and a saturated sodium thiosulfate solution was added for quenching. The liquids were separated, and the organic phase was retained. The solvent was removed by a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:12) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in the intermediate 1-2;

[0095] The intermediate 1-2 and the raw material 4 are dissolved in a mixed solution of toluene ethanol and water, and then ventilated 3 times, potassium carbonate and tetrakistriphenylphosphine palladium catalyst are added under nitrogen protection, stirred evenly, heated to 90 ° C, and refluxed for 6 hours; after the reaction is completed, the temperature is slightly lowered, diatomaceous earth is used for filtering, salt and catalyst are removed, and the filtrate is cooled to room temperature, washed three times with water, the organic phase is retained, and then the aqueous phase is extracted with ethyl acetate; after the organic phase is combined, anhydrous magnesium sulfate is used for drying, and a rotary evaporator is used to remove the solvent to obtain solid organic matter. A small amount of dichloromethane is used to completely dissolve the solid organic matter, and then it is slowly added dropwise to a petroleum ether solution, stirred evenly, and a precipitate is precipitated, and the solid is obtained by suction filtration, and it is rinsed with anhydrous ethanol and petroleum ether in turn, and dried to obtain raw material A.

[0096] Example 5

[0097]

[0098] After raw material A (40.00 mmol) and raw material B (40.00 mmol) were dissolved in toluene, Pd2(dba)3 (0.40 mmol), P(t-Bu)3 (2.00 mmol) and t-BuONa (80.00 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and stirred for reaction for 12 h. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:14) was used as an eluent, and the remaining substance was purified by column chromatography to obtain the compound shown in Intermediate 1 (15.68 g, yield: 76.67%);

[0099] After intermediate 1 (30.64 mmol) and raw material C (30.64 mmol) were dissolved in toluene, Pd2(dba)3 (0.30 mmol), P(t-Bu)3 (1.53 mmol) and t-BuONa (61.28 mmol) were added under N2 atmosphere, the temperature was raised to 120°C and the reaction was stirred for 14 hours. After the reaction was completed, diatomaceous earth was used for hot filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried with magnesium sulfate, and the solvent was removed with a rotary evaporator. Finally, a mixture of dichloromethane and petroleum ether (V:V=1:8) was used as an eluent, and the remaining substance was purified by column chromatography to obtain compound 98 (17.39 g, yield: 68.49%, Mw: 829.02).

[0100] Mass spectrometry test: theoretical value is 829.02; tested value is 828.79.

[0101] Elemental Analysis:

[0102] Calculated values: C, 89.83; H, 4.86; N, 3.38; O, 1.93.

[0103] The test values ​​are: C, 89.43; H, 5.19; N, 3.48; O, 2.11.

[0104] Example 6-30

[0105] The synthesis routes and principles of other compounds in the general formula 1 of the present invention are the same as those of the above-mentioned embodiments, so they are not listed here in detail. According to the above preparation method, the luminescent auxiliary material shown in Table 1 below can be obtained:

[0106] Table 1 Molecular formula, mass spectrum and yield of the compounds prepared in Examples 6-30

[0107]

[0108]

[0109] The organic electroluminescent device is prepared by using the luminescence auxiliary material provided in the above embodiments, and when the organic layer includes a luminescence auxiliary layer, the luminescence auxiliary layer includes the luminescence auxiliary material provided in any of the above embodiments.

[0110] Device Example 1

[0111] The preparation of an organic electroluminescent device containing a light-emitting auxiliary material specifically comprises the following steps:

[0112] 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;

[0113] b. HIL (hole injection layer): The evaporation rate of the hole injection layer is HT and P-dopant, and the chemical formula thereof is shown below; wherein the evaporation rate ratio of HT and P-dopant is 97:3, and the thickness is 10 nm;

[0114] c. HTL (hole transport layer): At a deposition rate of 100%, 120 nm of HT was vacuum-deposited on the hole injection layer as a hole transport layer.

[0115] d. Light-emitting auxiliary layer: At a deposition rate of , 10 nm of the compound 1 provided in Example 1 was vacuum-deposited on the hole transport layer as a light-emitting auxiliary layer;

[0116] e. EML (light-emitting layer): Then on the above-mentioned light-emitting auxiliary layer, The evaporation rate of the host material (Host) and the dopant material (Dopant) with a thickness of 25nm are vacuum evaporated as the light-emitting layer. The chemical formulas of the Host and Dopant are as follows; wherein the evaporation rate ratio of the Host and Dopant is 98:2;

[0117] f. HB (hole blocking layer): The evaporation rate is 5.0 nm, and the hole blocking layer is vacuum-deposited with a thickness of 5.0 nm;

[0118] g. ETL (Electron Transport Layer): At a deposition rate of , ET and Liq with a thickness of 30 nm were vacuum-deposited as an electron transport layer, and the chemical formula of ET is shown below; wherein the deposition rate ratio of ET to Liq is 50:50;

[0119] h. EIL (electron injection layer): The deposition rate is 1.0 nm, and a Yb (ytterbium) film layer is deposited to form an electron injection layer.

[0120] i. Cathode: 18 nm of magnesium and silver were evaporated at a deposition rate ratio of 1:9 to obtain an OLED device;

[0121] 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;

[0122] k. Package the vapor-deposited substrate: first, use the glue coating equipment to coat the cleaned cover with UV glue, then move the coated cover to the pressing section, place the vapor-deposited substrate on the upper end of the cover, and finally bond the substrate and cover with the bonding equipment, and complete the light curing of the UV glue at the same time.

[0123] The structural formula involved above is as follows:

[0124]

[0125] Device Example 2-30:

[0126] The light-emitting auxiliary layer in device example 1 is replaced with compounds 11, 53, 61, 98, 4, 16, 23, 26, 32, 38, 41, 44, 50, 54, 58, 62, 67, 70, 75, 79, 83, 89, 94, 97, 101, 107, 111, 119, and 124 to prepare device examples 2-30.

[0127] Device Comparison Examples 1-8:

[0128] This comparative example provides an organic electroluminescent device. The only difference between the preparation method of the organic electroluminescent device and the device embodiment 1 is that the organic electroluminescent device uses existing comparative compounds a, b, c, d, e, f, g, and h to replace the luminescent auxiliary material (compound 1) in the above device embodiment 1 for evaporation to prepare device comparative examples 1-8. Among them, the chemical structural formulas of comparative compounds a, b, c, d, e, f, g, and h are:

[0129]

[0130] The driving voltage, luminous efficiency, BI value and life of the organic electroluminescent devices containing the luminescent auxiliary material obtained in the device embodiments 1-30 and the device comparative examples 1-8 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2.

[0131] Table 2 Luminous characteristics test results (brightness value is 1000nits)

[0132]

[0133]

[0134] Note: In blue top-emitting devices, the current efficiency is greatly affected by chromaticity. Therefore, the influence of chromaticity on efficiency is taken into account, and the ratio of luminous efficiency to CIEy is defined as BI value, that is, BI = (cd / A) / CIEy.

[0135] As can be seen from Table 2, compared with the existing organic electroluminescent devices provided by device comparison examples 1-8, the organic electroluminescent device embodiments 1-30 prepared using the luminescent auxiliary materials provided by the present invention have improved luminous efficiency and lifespan while reducing driving voltage.

[0136] Compared with the comparative compound, the compound of the present invention has a different parent core. By changing the side chain and extending the molecular conjugation, the hole mobility of the compound can be improved. The positional connection group of the parent core naphthoxybenzofuran naphthalene changes the spatial structure, making it more adaptable to the device, which can effectively improve the lifespan and luminous efficiency of the OLED device and the glass transition temperature while reducing the driving voltage.

[0137] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0138] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent compound, characterized in that: Its molecular formula is shown in general formula (I): ； The general formula (I) is selected from any one of the following general formulas (III-1) to (III-15): ； Ar2 is an unsubstituted C6-C30 aryl group; R2-R5 are each independently selected from hydrogen, deuterium, and halogen groups.

2. An organic electroluminescent compound according to claim 1, characterized in that: Ar2 is selected from the following structural formula: ， Wherein R6 is selected from unsubstituted C1-C15 alkyl.

3. An organic electroluminescent compound according to claim 1, characterized in that: The general formula 1 is represented by any one of the following formulas (1) to (126): 。 4. A method for preparing an organic electroluminescent compound according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) After raw materials A and B are dissolved in an organic solvent, Pd2(dba)3, P(t-Bu)3 and t-BuONa are added under a N2 atmosphere, the temperature is raised to 110-120°C and stirred for reaction for 10-12h. After the reaction is completed, the mixture is filtered, washed, dried, evaporated and purified to obtain the compound shown in intermediate 1; (2) Under N2 protection, the intermediate 1, raw material C, Pd2(dba)3, P(t-Bu)3 and t-BuONa are heated to 110-120°C and stirred for reaction for 12-14 hours. After the reaction is completed, the mixture is filtered, washed, dried, evaporated and purified to obtain a compound of formula 1; The specific synthetic route is shown in Reaction Scheme 1: ； Reaction I Wherein R1~R5, Ar1, Ar2 have the definitions given in claim 1.

5. Use of the organic electroluminescent compound according to any one of claims 1 to 3, characterized in that: The organic electroluminescent compound is used in preparing an organic light-emitting device or a fluorescent lamp.

6. An organic electroluminescent device, characterized in that: comprising a first electrode, a second electrode, and one or more organic layers disposed between the first electrode and the second electrode; and, The organic layer includes a light-emitting auxiliary layer, and also includes one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, a light extraction layer and a capping layer; and, The light-emitting auxiliary layer comprises one or more organic electroluminescent compounds as described in any one of claims 1 to 3.

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