An organic electroluminescent material and its application

Abstract

The present invention belongs to the technical field of organic electroluminescent materials, and particularly relates to an organic electroluminescent material and its application. The organic electroluminescent material developed by the present invention can significantly improve the carrier injection efficiency, reduce the interlayer energy level difference, balance the electron and hole transport rates, and can effectively improve the efficiency of the organic electroluminescent device and extend the lifespan of the organic electroluminescent device. When the organic electroluminescent material is used as an organic functional layer material, the first host material and the second host material act synergistically, enabling the device to have a low driving voltage (below 3.43 V), a high current efficiency (above 22.77 Cd / A), and a high lifespan (above 230 h).

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and particularly relates to an organic electroluminescent material and its application. Background Art

[0002] An organic electroluminescent device (OLED) converts electrical energy into light by applying electricity to an organic electroluminescent material, and generally includes an anode, a cathode, and an organic layer formed between these two electrodes. The organic layer of the organic EL device may include a hole injection layer, a hole transport layer, a hole auxiliary layer, a light emission auxiliary layer, an electron blocking layer, a light emitting layer (containing a host material and a dopant material), an electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. According to their functions, the materials used in the organic layer can be classified into hole injection materials, hole transport materials, hole auxiliary materials, light emission auxiliary materials, electron blocking materials, light emitting materials, electron buffer materials, hole blocking materials, electron transport materials, electron injection materials, etc. In an organic EL device, holes from the anode and electrons from the cathode are injected into the light emitting layer by applying a voltage, and excitons with high energy are generated by the recombination of holes and electrons. The organic light emitting compound emits light by moving energy to the excited state and utilizing the energy when the organic light emitting compound returns from the excited state to the ground state.

[0003] Currently, due to reasons such as the low stability of organic functional materials and the imbalance of carrier mobility, problems such as low luminous efficiency, high driving voltage, and short lifespan of organic electroluminescent devices seriously limit the application of organic electroluminescent devices. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of low luminous efficiency, high driving voltage, and short lifespan of existing organic electroluminescent devices, so as to provide an organic electroluminescent material and its application.

[0005] Definition of substituent terms in the present invention:

[0006] As used in the present invention, the term "halogen" may include fluorine, chlorine, bromine, or iodine.

[0007] As used in the present invention, the term "C1-C30 alkyl" refers to a monovalent substituent derived from a straight-chain or branched-chain saturated hydrocarbon having 1 to 30 carbon atoms, and examples thereof include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, and hexyl.

[0008] As used in the present invention, the term "C3-C30 cycloalkyl" refers to a monocyclic hydrocarbon or polycyclic hydrocarbon derived from a hydrocarbon having 1 to 30 ring backbone carbon atoms, and the cycloalkane may include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclohexylmethyl, adamantyl, etc.

[0009] In the present invention, aryl and arylene include monocyclic, polycyclic or fused-ring aryl groups, and the rings may be interrupted by short non-aromatic units and may include spiro structures, including but not limited to phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, phenylphenanthryl, binaphthyl, phenylnaphthyl, naphthylphenyl, anthryl, indenyl, triphenylene, tetraphenylene, pyrenyl, perylenyl, fluorenyl, phenylfluorenyl, diphenylfluorenyl, benzofluorenyl, spirobifluorenyl, -yl, naphthacenyl, fluoranthenyl, etc.

[0010] In the present invention, heteroaryl and heteroarylene include monocyclic, polycyclic or fused-ring heteroaryl groups, and the rings may be interrupted by short non-aromatic units, and the heteroatoms include nitrogen, oxygen and sulfur. Including but not limited to furyl, phenylthio, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuryl, benzothienyl, isobenzofuryl, dibenzofuryl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenothiazinyl, phenanthridinyl, benzodioxolyl, dihydroacridinyl, and their derivatives, etc.

[0011] As used in the present invention, the term "substituted" means that a hydrogen atom in a compound is replaced by another substituent. The position is not limited to a specific position as long as the hydrogen at that position can be replaced by a substituent. And it also includes the replacement of a hydrogen atom by a group formed by the connection of two or more substituents. When two or more substituents appear, the two or more substituents may be the same or different. For example, the group formed by the connection of two or more substituents can be pyridine-triazine. That is, pyridine-triazine can be interpreted as a heteroaryl substituent or a substituent in which two heteroaryl substituents are connected.

[0012] As used in the present invention, unless otherwise specified, a hydrogen atom includes protium, deuterium and tritium.

[0013] In the present invention, in the definition of a group, the range of the number of carbon atoms is defined, and the number of carbon atoms is any integer within the defined range. For example, C6-C30 aryl represents that the number of carbon atoms of the aryl can be any integer within the range of 6-60, such as 6, 8, 10, 13, 15, 17, 20, 22, 25, or 30, etc.

[0014] In the present invention represents a linking bond, and the linking bond can be a single bond.

[0015] The present invention provides an organic electroluminescent material, comprising a plurality of host materials, the plurality of host materials comprising a first host material and a second host material, and the first host material comprises a compound represented by formula (I):

[0016]

[0017] wherein, X is selected from O, S, Se, NAr, CR 6 R 7 ;

[0018] R 1 is —L 1 Ar 1 R 2 is —L 2 Ar 2 R 3 is —L 3 Ar 3 ;

[0019] Ar is selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C5-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl,

[0020] R 6 R 7 each independently is selected from a hydrogen atom, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl,

[0021] L 1 L 2 L 3 each independently is selected from a linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C3-C30 heteroarylene;

[0022] Ar 1 Ar 2 Ar 3Each independently selected from hydrogen, deuterium, protium, tritium, halogen, cyano, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C3-C60 heteroarylamino, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, where Ar 1 , Ar 2 , Ar 3 at least one of which is a structure represented by formula (II),

[0023]

[0024] R 4 is —L 4 Ar 4 , R 5 is —L 5 Ar 5 ,

[0025] wherein, L 4 , L 5 each independently selected from a linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C3-C30 heteroarylene;

[0026] Ar 4 -Ar 5 each independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0027] The substituents of the substituted C1-C30 alkyl, substituted C3-C30 cycloalkyl, substituted C5-C60 aryl, substituted C3-C60 heteroaryl, substituted C1-C20 alkyl, substituted C6-C30 aryl, substituted C3-C30 heteroaryl, substituted C6-C60 arylamino, substituted C3-C60 heteroarylamino, substituted C6-C60 aryl, substituted C3-C60 heteroaryl, substituted C6-C30 arylene, substituted C3-C30 heteroarylene are selected from one or a combination of two of deuterium, halogen, cyano, C1-C6 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, C3-C30 heteroaryl;

[0028] The second host material comprises a compound represented by formula (2):

[0029]

[0030] wherein, L is selected from a linking bond, substituted or unsubstituted C6-C30 arylene, substituted or unsubstituted C3-C30 heteroarylene;

[0031] Ar 8 , Ar 9Each independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0032] The substituents of the substituted C6-C30 arylene, substituted C3-C30 heteroarylene, substituted C6-C30 aryl, and substituted C3-C30 heteroaryl are selected from one or a combination of two of deuterium, halogen, cyano, C1-C6 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, and C3-C30 heteroaryl.

[0033] Optionally, in the second host material, L is a linking bond; Ar 8 , Ar 9 Each independently selected from substituted or unsubstituted groups as follows: phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, triphenylene, -yl, dimethylfluorenyl, spirobifluorenyl, fluoranthenyl, diphenylfluorenyl, benzo-dimethylfluorenyl, benzo-diphenylfluorenyl, benzo-spirobifluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, phenylcarbazolyl, dipyridyl, pyrimidinyl, triazinyl.

[0034] Optionally, the Ar 4 , Ar 5 Each independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C60 heteroaryl.

[0035] Optionally, the Ar 4 , Ar 5 Each independently selected from substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzoselenophenyl.

[0036] Optionally, the Ar is selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0037] Preferably, the Ar is selected from phenyl, naphthyl, biphenyl, terphenyl, triphenylene, -yl, dibenzofuranyl, dibenzothiophenyl;

[0038] And / or, Ar 4 , Ar 5 Each independently selected from substituted or unsubstituted groups as follows: phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, triphenylene, -yl, dibenzofuranyl, benzonaphthofuranyl, dibenzothiophenyl, dibenzoselenophenyl, triphenylene, dimethylfluorenyl, spirobifluorenyl, fluoranthenyl, carbazolyl, phenylcarbazolyl, diphenylfluorenyl, benzo-dimethylfluorenyl, benzo-diphenylfluorenyl, benzo-spirobifluorenyl, pyridyl, pyrimidinyl, triazinyl.

[0039] Optionally, the L 1 , L 2 , L 3 is a single bond, and Ar 1 , Ar 2 , Ar 3 are each independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

[0040] Optionally, the Ar 1 , Ar 2 , Ar 3 are each independently selected from substituted or unsubstituted dibenzofuranyl and substituted or unsubstituted dibenzothiophenyl.

[0041] Optionally, the Ar 4 , Ar 5 are each independently selected from the structures shown in the following formulas (III) and (IV):

[0042]

[0043] RT 1 -RT 6 are each independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C7-C30 aralkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C4-C30 heteroaralkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C3-C30 heterocycloalkyl, substituted or unsubstituted C3-C30 cycloalkenyl, substituted or unsubstituted C1-C30 alkoxy, and substituted or unsubstituted C6-C30 aryloxy, wherein any two adjacent ones substituted by the same phenyl group can be fused into a C6-C30 ring A,

[0044] Y is selected from O, S, NAr, CR 6 R 7 , wherein the definitions of Ar, R 6 R 7 are the same as those in claim 1;

[0045] Preferably, the ring A is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and substituted or unsubstituted phenanthryl;

[0046] When there are multiple R T1 -R T6 , R T1 -R T6 are each independent of one another and may be the same or different;

[0047] Y is selected from O, S, NAr, CR 6 R 7 ;

[0048] wherein Ar, R 6 , R 7 are as defined above.

[0049] Optionally, the compound represented by formula (I) has a structure shown in any one of Chemical Formulas 1-1 to 1-17:

[0050]

[0051]

[0052] Optionally, the compound represented by formula (1) has a structure shown in any one of the following:

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] Optionally, the compound represented by formula (2) has any of the following structures:

[0089]

[0090]

[0091]

[0092]

[0093] Optionally, the mass ratio of the compound represented by formula (1) to the compound represented by formula (2) is 1:9 - 9:1;

[0094] Preferably, the mass ratio of the compound represented by formula (1) to the compound represented by formula (2) is 2:8 - 8:2;

[0095] More preferably, the mass ratio of the compound represented by the formula (1) to the compound represented by the formula (2) is 3:7 - 7:3; Further preferably, the mass ratio of the compound represented by the formula (1) to the compound represented by the formula (2) is 4:6 - 6:4.

[0096] The present invention also provides an application of the above-mentioned organic electroluminescent material in the preparation of an optical device.

[0097] The present invention also provides an organic electroluminescent device, which includes an anode and a cathode, and an organic layer disposed between the anode and the cathode, and the organic layer includes the above-mentioned organic electroluminescent material; Preferably, the light-emitting layer in the organic layer includes the above-mentioned organic electroluminescent material.

[0098] The present invention also provides an organic electroluminescent device, which includes the above-mentioned organic electroluminescent device.

[0099] Preferably, the optical device includes any one of an organic electroluminescent device, an organic field-effect transistor, an organic thin-film transistor, an organic light-emitting transistor, an organic integrated circuit, an organic solar cell, an organic field quenching device, a light-emitting electrochemical cell, an organic laser diode or an organic photoreceptor.

[0100] The present invention also provides an organic electroluminescent device, which includes an anode and a cathode, and an organic layer disposed between the anode and the cathode, and the organic layer includes the organic electroluminescent material as described above, and preferably, the light-emitting layer in the organic layer includes the organic electroluminescent material as described above.

[0101] Preferably, the organic layer includes a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer which are sequentially stacked from the anode side to the cathode side;

[0102] Preferably, the material of the light-emitting layer includes a host material and a guest material, and the host material includes the above-mentioned organic electroluminescent material.

[0103] Preferably, the guest material includes a phosphorescent dopant, and the phosphorescent dopant includes a complex containing a transition metal.

[0104] The term "organic electroluminescent material" in the present invention means a material that can be used in an organic electroluminescent device and can contain at least one compound. If necessary, the organic electroluminescent material can be included in any layer constituting the organic electroluminescent device. For example, the organic electroluminescent material can be a hole injection material, a hole transport material, a hole assisting material, a light emitting assisting material, an electron blocking material, a light emitting material (including a host material and a dopant material), an electron buffer material, a hole blocking material, an electron transport material, an electron injection material, etc.

[0105] The term "a plurality of organic electroluminescent materials" in the present disclosure means one or more combinations of organic electroluminescent materials containing at least two compounds, and the materials can be included in any layer constituting the organic electroluminescent device. It can mean both the materials before being included in the organic electroluminescent device (e.g., before vapor deposition) and the materials after being included in the organic electroluminescent device (e.g., after vapor deposition). For example, a plurality of organic electroluminescent materials can be a combination of at least two compounds, and the materials can be included in at least one of the following: a hole injection layer, a hole transport layer, a hole assisting layer, a light emitting assisting layer, an electron blocking layer, a light emitting layer, an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer. The at least two compounds can be included in the same layer or different layers, and can be co-evaporated by mixing or co-evaporated, or can be evaporated individually.

[0106] The term "a plurality of host materials" in the present disclosure means an organic electroluminescent material containing a combination of at least two host materials. It can mean both the materials before being included in the organic electroluminescent device (e.g., before vapor deposition) and the materials after being included in the organic electroluminescent device (e.g., after vapor deposition). The plurality of host materials of the present disclosure can be included in any light emitting layer constituting the organic electroluminescent device. Two or more compounds included in the plurality of host materials of the present disclosure can be included in one light emitting layer, or can be included in different light emitting layers respectively. For example, when two or more host materials are included in one layer, the layer can be formed by co-evaporation by mixing, or can be formed simultaneously by separate co-evaporation.

[0107] The technical solution of the present invention has the following advantages:

[0108] The organic electroluminescent material provided by the present invention, through the combination of at least one compound with the structure shown in formula (1) and at least one compound with the structure shown in formula (2), and using their combination as the host material of the light-emitting layer, significantly reduces the turn-on voltage of the organic light-emitting device, significantly improves the luminous efficiency, and significantly extends the lifespan. An organic electroluminescent device containing the host material with the specific composition of the present invention can provide an organic electroluminescent device having improved luminous efficiency and lifespan characteristics compared with a conventional organic electroluminescent device, and further obtain a display system or lighting system having improved luminous efficiency and lifespan characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0110] Figure 1 It is a schematic structural diagram of an organic electroluminescent device in an embodiment of the device of the present invention;

[0111] Among them, 1 - substrate; 2 - anode; 3 - hole injection layer; 4 - hole transport layer; 5 - light-emitting layer; 6 - electron transport layer; 7 - electron injection layer; 8 - cathode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0112] The following embodiments are provided to better further understand the present invention. They are not limited to the best embodiments, and do not constitute a limitation on the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other prior arts falls within the protection scope of the present invention.

[0113] For those steps or conditions not specified in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments not specified by the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0114] Preparation Example of the First Host Material

[0115] 1. The preparation method of the compound with the N-4 structure includes the following steps:

[0116]

[0117] 1.1 Synthesis of Intermediate N-4B’

[0118] Under nitrogen purging, 20 g (1.0 eq) of 4a, 9.87 g (1.0 eq) of 4b, 1.7 g (2% eq) of Pd(PPh3)4, 8.37 g (2.0 eq) of NaHCO3, 180 mL of tetrahydrofuran (4a:tetrahydrofuran = 1 g:9 mL), and 60 mL of ultrapure water (4a:ultrapure water = 1 g:3 mL) were added to a 500 mL three-necked flask equipped with a magnetic stirrer. The reaction was complete after 2 h at 65 °C. The product was obtained by column purification, yielding 10 g of the product.

[0119] 1.2 Synthesis of Intermediate N-4B

[0120] 10 g (1.0 eq) of Intermediate N-4B’, 20.5 g (6.0 eq) of anhydrous FeCl3, and 100 mL of anhydrous dichloromethane (Intermediate N-4B’:dichloromethane = 1 g:10 mL) were added to a 250 mL three-necked flask equipped with a magnetic stirrer. The reaction was complete after 1 h at -10 °C. The product was obtained by column purification, yielding 7 g of the product.

[0121] Elemental analysis: For C48H32N2, theoretical values: C, 90.54; H, 5.07; N, 4.40; found values: C, 90.53; H, 5.08; N, 4.41; HRMS(ESI) m / z (M+): theoretical value: 636.26; found value: 637.55.

[0122] 1.3 Synthesis of Compound N-4

[0123] Under nitrogen purging, 7 g (1.0 eq) of N-4B, 4.0 g (1.1 eq) of N-4A, 0.27 g (2% eq) of Pd2(dba)3, 2.85 g (2.0 eq) of t-BuONa, and 70 mL of anhydrous toluene (N-4B:anhydrous toluene = 1 g:10 mL) were added to a 250 mL three-necked flask equipped with a magnetic stirrer. The reaction was complete after 2 h at 100 °C. The product was obtained by column purification, yielding 5 g of the product.

[0124] 2. Preparation method of a compound with an N-5 structure, comprising the following steps:

[0125]

[0126] Synthesis of Compound N-5

[0127] Under nitrogen purging, 7 g (1.0 eq) of Intermediate N-4B, 4.82 g (1.1 eq) of N-5A, 0.27 g (2% eq) of Pd2(dba)3, 2.85 g (2.0 eq) of t-BuONa, and 70 mL of anhydrous toluene (Intermediate N-4B:anhydrous toluene = 1 g:10 mL) were added to a 250 mL three-necked flask equipped with a magnetic stirrer. The reaction was complete after 2 h at 100 °C. The product was obtained by column purification, yielding 5 g of the product.

[0128] Elemental analysis: C52H34N2 Theoretical values: C, 90.93; H, 4.99; N, 4.08; Measured values: C, 90.92; H, 4.98; N, 4.10; HRMS(ESI) m / z(M+): Theoretical value: 686.27; Measured value: 687.22.

[0129] 3. Preparation method of the compound with N-14 structure, including the following steps:

[0130]

[0131] Synthesis of compound N-14

[0132] Under nitrogen purge, add 7 g (1.0 eq) of intermediate N-4B, 4.4 g (1.1 eq) of N-14A, 0.27 g (2% eq) of Pd2(dba)3, 2.85 g (2.0 eq) of t-BuONa, and 70 mL of anhydrous toluene (intermediate N-4B:anhydrous toluene = 1 g:10 mL) into a 250 mL three-necked flask equipped with magnetic stirring. React completely at 100 °C for 2 h. Purify by column chromatography to obtain 5 g of the product.

[0133] Elemental analysis: C50H32N2 Theoretical values: C, 90.88; H, 4.88; N, 4.24; Measured values: C, 90.86; H, 4.88; N, 4.26; HRMS(ESI) m / z(M+): Theoretical value: 660.25; Measured value: 661.37.

[0134] The preparation methods of the first host materials with other structures in the following table are similar to the compounds shown in the above N-4, N-5, and N-14 structures. Specifically, the raw materials used and the products obtained are shown in the following table:

[0135]

[0136]

[0137]

[0138]

[0139] The characterization data of the products are shown in the following table:

[0140]

[0141] 4. Preparation method of the compound with N-423 structure, including the following steps:

[0142]

[0143] Synthesis of Intermediate N-423B’

[0144] Add 20 g of 423a, 29.9 g of 423b, 2.3 g of Pd[P(C6H5)3]4, 27.9 g of K2CO3, 280 mL of toluene, 120 mL of H2O, and 120 mL of ethanol into a 1000 mL three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a thermometer. Replace the air with nitrogen three times, and react at 85 °C under nitrogen protection for 150 min starting from the beginning of heating. After the reaction is completed, add 120 mL of water to quench the reaction. After liquid separation, rotary evaporate to obtain an oily substance (wet weight 44 g), and obtain 25 g of N-423B’ after vacuum pumping.

[0145] Synthesis of Intermediate N-423B

[0146] Add the crude product of N-423B’ (oily substance) and 750 mL of dichloromethane (N-423B’: DCM = 1 g: 30 mL) into a 2 L three-necked flask equipped with a stirrer and a thermometer. Control the temperature at -5 ± 2 °C, and add ferric chloride in two batches, adding 3 equivalents of ferric chloride every 15 min while controlling the temperature at -5 ± 2 °C. After the reaction is completed, slowly add 750 mL of ethanol (N-423B’: ethanol = 1 g: 30 mL) while controlling the temperature below 0 °C. After adding, continue stirring for 0.5 h, and yellowish-white solids will precipitate. Filter, wash the filter cake with 250 mL of ethanol (N-423B’: ethanol = 1 g: 10 mL) to obtain yellow solids. Then dissolve in 1.75 L of chlorobenzene, desolvate and crystallize. When it naturally cools to 60 ± 5 °C, add 250 mL of n-hexane solution dropwise and filter to obtain 20 g of crude product N-423.

[0147]

[0148] Synthesis of Compound N-423

[0149] Add 25 g of N-423A, 40.48 g of N-423B, 1.86 g of Pd2(dba)3, 1.67 g of sphos, 24.4 g of t-BuONa, and 500 mL of toluene into a 1000 mL three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a thermometer. Replace the air with nitrogen three times, and react at 110 °C under nitrogen protection for 120 min starting from the beginning of heating. After the reaction is completed, add 120 mL of water to quench the reaction. After liquid separation, rotary evaporate, pass through a column, and dry to obtain 35 g of crude product N-423.

[0150] Elemental analysis: C42H27NO; Theoretical values: C, 89.81; H, 4.85; N, 2.49; O, 2.85; Measured values: C, 89.78; H, 4.86; N, 2.51; HRMS(ESI) m / z (M+): Theoretical value: 561.21; Measured value: 562.29.

[0151] 5. Preparation method of the compound with N-425 structure, comprising the following steps:

[0152]

[0153] Synthesis of compound N-425

[0154] Add 14 g of N-425A, 18.8 g of N-423B, 0.86 g of Pd2(dba)3, 1.9 g of sphos, 9.1 g of t-BuONa, and 150 mL of toluene into a 500 mL three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a thermometer. Replace the air with nitrogen three times, and react at 110 °C under nitrogen protection. React for 120 min starting from the temperature rise. After the reaction is completed, add 150 mL of water to quench the reaction. After liquid separation, spin-dry, slurry with ethanol, and then desolvate and crystallize with toluene to obtain 16 g of crude product N-425.

[0155] Elemental analysis: C46H29NO Theoretical values: C, 90.32; H, 4.78; N, 2.29; O, 2.62; Measured values: C, 90.30; H, 4.77; N, 2.32; HRMS(ESI) m / z (M+): Theoretical value: 611.22; Measured value: 612.45.

[0156] The preparation methods of the first host materials with other structures in the following table are similar to those of the compounds shown in the above N-423 and N-425 structures. Specifically, the raw materials used and the obtained products are shown in the following table:

[0157]

[0158]

[0159]

[0160]

[0161]

[0162] The characterization data of the products are shown in the following table:

[0163]

[0164] 6. Preparation method of a compound with an N-912 structure, comprising the following steps:

[0165]

[0166] A mixture of 35.2 g (100 mmol) of 2,7-dibromo-9,9-dimethyl-9H-fluorene, 21.8 g (110 mmol) of 2-biphenylylboronic acid, 2.31 g (2 mmol) of Pd(PPh3)4, 75 ml of 2M Na2CO3, 150 ml of EtOH and 300 ml of toluene was degassed and placed under nitrogen, and then heated at 100 °C for 12 hours. After completion of the reaction, the mixture was cooled to room temperature. The organic layer was extracted with ethyl acetate and water, dried over anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica gel to give the product as a white solid (26.8 g, 63.0 mmol, 63%).

[0167] In a 3000 ml three-necked flask that was degassed and filled with nitrogen, 26.8 g (60 mmol) of 2-(biphenyl-2-yl)-7-bromo-9,9-dimethyl-9H-fluorene was dissolved in anhydrous dichloromethane (1500 ml), then 97.5 g (600 mmol) of iron(III) chloride was added and the mixture was stirred for one hour. 500 ml of methanol was added to the mixture and the organic layer was separated and the solvent was removed in vacuo. The residue was purified by column chromatography on silica gel (hexane-dichloromethane) to give a white solid (10.7 g, 25.3 mmol, 40%).

[0168]

[0169] A mixture of 20 g (41.3 mmol) of N-(biphenyl-4-yl)-9,9'-spirobifluorene-2-amine, 14 g (49.5 mmol) of 1-bromo-4-iodobenzene, 2.4 g (12.4 mmol) of copper(I) iodide, 17.1 g (123.9 mmol) of potassium carbonate and 300 ml of DMF was refluxed overnight under nitrogen. After completion of the reaction, it was then cooled to room temperature. The organic layer was extracted with ethyl acetate and water, dried over anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica gel (hexane-dichloromethane) to give 26.3 g (yield 43%) of the product as a white solid.

[0170] A mixture of 10 g (15.6 mmol) of N-(biphenyl-4-yl)-N-(4-bromophenyl)-9,9'-spirobi[fluorene]-2-amine, 4.75 g (18.72 mmol) of bis(pinacolato)diboron, 0.18 g (0.156 mmol) of tetrakis(triphenylphosphine)palladium, 2 g (20.28 mmol) of potassium acetate and 300 ml of 1,4-dioxane was degassed and placed under nitrogen, and then heated at 90 °C for 16 h. After completion of the reaction, the mixture was cooled to room temperature. The organic layer was extracted with ethyl acetate and water, dried over anhydrous magnesium sulfate, the solvent was removed and the product was purified by column using a mixture of hexane and ethyl as eluent, giving 8.77 g of a pale yellow product (yield 82%).

[0171]

[0172] A mixture of 15 g (35.43 mmol) of 12-bromo-10,10-dimethyl-10H-indeno[1,2-b]triphenylene, 29.1 g (42.51 mmol) of N-(biphenyl-4-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9,9'-spirobifluorene-2-amine, 0.41 g (0.35 mmol) of tetrakis(triphenylphosphine)palladium, 23 ml of 2M Na2CO3, 100 ml of EtOH and 200 ml of toluene was degassed and placed under nitrogen, and then heated at 100 °C for 8 hours. After completion of the reaction, the mixture was cooled to room temperature. The organic layer was extracted with dichloromethane and water, dried over anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography (hexane-dichloromethane) packed with silica gel, giving 17.5 g (yield 55%) of the product as a yellow solid.

[0173] Elemental analysis: C70H47N Theoretical: C, 93.20; H, 5.25; N, 1.55; Found: C, 93.16; H, 5.27; N, 1.57; HRMS(ESI) m / z (M+): Theoretical: 901.37; Found: 902.21.

[0174] 7. A method for preparing a compound having the N-895 structure, comprising the following steps:

[0175]

[0176] A mixture of 5 g (11.8 mmol) of 12-bromo-10,10-dimethyl-10H-indeno[1,2-b]triphenylene, 6.8 g (14.1 mmol) of N-(biphenyl-4-yl)-9,9'-spirobifluorene-2-amine, 0.03 g (0.11 mmol) of palladium(II) acetate, 0.04 g (0.11 mmol) of 2-(dicyclohexylphosphino)biphenyl, 1.7 g (17.7 mmol) of sodium tert-butoxide and 100 ml of toluene was refluxed overnight under nitrogen. After completion of the reaction, it was then cooled to room temperature. The organic layer was extracted with dichloromethane and water, dried over anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography (hexane-dichloromethane) packed with silica gel to give 5.8 g (yield 60%) of the product as a yellow solid.

[0177] Elemental analysis: For C64H43N, theoretical values: C, 93.06; H, 5.25; N, 1.70; found values: C, 93.02; H, 5.25; N, 1.73; HRMS (ESI) m / z (M+): theoretical value: 825.34; found value: 826.19.

[0178] The preparation methods of the first host materials with other structures in the following table are similar to the compounds shown in the above N-895 and N-912 structures. Specifically, the raw materials used and the products obtained are shown in the following table:

[0179]

[0180]

[0181] The characterization data of the products are shown in the following table:

[0182]

[0183] Preparation examples of the second host material

[0184] 1. The preparation method of the compound with M-1 structure includes the following steps:

[0185]

[0186] Take a 50 mL two-necked round-bottom flask, place a magnetic stir bar and connect it to a reflux condenser. After drying, fill it with nitrogen. Add compound M-1-1 (10 mmol), M-1-2 (12 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), potassium carbonate (20 mmol), 15 ml of toluene, 5 mL of ethanol and 5 mL of distilled water respectively, and stir the mixture at 85 °C for 8 hours. After completion of the reaction, concentrate part of the solvent, cool down and filter. The filter cake is desolvated and crystallized with toluene to obtain compound M-1 (3.3 g, yield: 76.7%).

[0187] Elemental analysis: C32H20N4 Theoretical values: C, 85.89; H, 4.42; N, 9.69; Measured values: C, 85.82; H, 4.44; N, 9.65; HRMS(ESI) m / z (M+): Theoretical value: 433.15; Measured value: 434.12.

[0188] 2. Preparation method of the compound with M-34 structure, comprising the following steps:

[0189]

[0190] Synthesis of intermediate M-34-3

[0191] Take a 100 mL two-necked round-bottom flask, place a magnetic stir bar and connect a reflux condenser above. After drying, fill it with nitrogen. Respectively add compound M-34-1 (14.1 mmol, CAS 1700-02-3), M-34-2 (18.3 mmol), tetrakis(triphenylphosphine)palladium (0.7 mmol), potassium carbonate (28.2 mmol), 42 mL of toluene, 10 mL of ethanol and 14 mL of distilled water, and stir the mixture at 90 °C for 8 hours. After the reaction is completed, dropwise add the mixture into methanol, and filter the obtained solid. Purify the obtained solid by column chromatography to obtain compound M-34-3 (4.2 g, yield: 58.8%).

[0192] Synthesis of M-34

[0193] Take a 100 mL two-necked round-bottom flask, place a magnetic stir bar and connect a reflux condenser above. After drying, fill it with nitrogen. Respectively add compound M-34-3 (20.1 mmol), M-34-4 (24.1 mmol), tetrakis(triphenylphosphine)palladium (0.4 mmol), potassium carbonate (40.2 mmol), 80 mL of toluene, 25 mL of ethanol and 25 mL of distilled water, and stir the mixture at 85 °C for 6 hours. After the reaction is completed, concentrate part of the solvent, cool down and filter. The filter cake is desolvated and crystallized with chlorobenzene to obtain compound M-34 (10 g, yield: 77.1%).

[0194] Elemental analysis: C32H20N4 Theoretical values: C, 83.46; H, 4.38; N, 12.17; Measured values: C, 83.44; H, 4.38; N, 12.18; HRMS(ESI) m / z (M+): Theoretical value: 460.17; Measured value: 461.04.

[0195] The preparation methods of the second host materials with other structures in the following table are similar to the compounds shown in the above M-1 and M-34 structures. Specifically, the raw materials used and the obtained products are shown in the following table:

[0196]

[0197] The characterization data of the product are shown in the following table:

[0198]

[0199]

[0200] Device Example

[0201] This example provides an organic electroluminescent device, as Figure 1 shown, including an anode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8 that are sequentially stacked on a substrate 1. Its device structure is: anode (indium tin oxide (ITO) coated glass substrate) / hole injection layer (HIL) / hole transport layer (HTL) / light-emitting layer (EML) / electron transport layer (ETL) / electron injection layer (EIL) / cathode (Al).

[0202] The materials required for manufacturing the OLED are as follows:

[0203]

[0204] The preparation of the above organic electroluminescent device includes the following steps:

[0205] (1) Substrate cleaning: The glass substrate coated with a transparent ITO coating is ultrasonically treated in an aqueous cleaning agent (the composition and concentration of the aqueous cleaning agent: glycol solvent ≤ 10 wt%, triethanolamine ≤ 1 wt%), rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol (volume ratio 1:1), baked in a clean environment until all moisture is removed, and then cleaned with ultraviolet light and ozone.

[0206] (2) Evaporation of the organic light-emitting functional layer:

[0207] Place the glass substrate with the anode layer in a vacuum chamber, evacuate to 1×10 -6 to 2×10 -4 Pa, and vacuum evaporate a mixture of NDP-9 and HT on the anode layer film, where the mass ratio of NDP-9 to HT is 3:97, as the hole injection layer, with an evaporation thickness of 10 nm;

[0208] 2) Preparation of the organic layer:

[0209] Transfer the ITO transparent substrate to an evaporation device and evacuate to 1×10 -6 to 2×10 -4Pa, a 10 nm hole injection layer (HIL) / 80 nm hole transport layer (HTL) / 38 nm emitting layer (EML) / 30 nm electron transport layer (ETL) / 1 nm electron injection layer (EIL) / 80 nm thick cathode (Al) were sequentially evaporated on the anode film.

[0210] Wherein:

[0211] The material of the hole injection layer (HIL) is a mixture of NDP-9 and HT, where the mass ratio of NDP-9 to HT is 3:97;

[0212] The material of the hole transport layer (HTL) is HT;

[0213] The material of the emitting layer (EML) includes a host material and a guest material. The host material is the compound represented by formula (I) and the compound represented by formula (2) prepared in the present invention, and the guest material is (piq)2Ir(acac); the specific materials and ratios are shown in Table 1;

[0214] The material of the electron transport layer (ETL) is shown in Table 1;

[0215] The material of the electron injection layer (EIL) is LiQ;

[0216] The cathode is aluminum;

[0217] The parameters such as the layers, their materials, and thicknesses in the organic electroluminescent devices provided in each example are shown in the following table.

[0218] Table 1

[0219]

[0220]

[0221] Device performance test:

[0222] Instrument: The characteristics such as current, voltage, brightness, and emission spectrum of the device were synchronously tested using a PR 650 spectral scanning luminance meter and a Keithley K 2400 digital source meter system;

[0223] Test conditions for the organic electroluminescent devices provided in each example and comparative example:

[0224] Optoelectronic property test conditions: Current density is 10 mA / cm 2 .

[0225] Lifetime test: Current density is 50 mA / cm 2 , and the time (in hours) was recorded when the brightness of the test device decreased to 95% of the original brightness.

[0226] The test results of the device performance are shown in the following table:

[0227] Item Driving Voltage (V) Current Efficiency (Cd / A) Lifetime T95 (hrs) Example 1 3.34 25.66 251.7 Example 2 3.32 23.11 241.6 Example 3 3.40 22.81 238.8 Example 4 3.31 26.11 244.2 Example 5 3.35 24.87 250.0 Example 6 3.43 22.77 230.2 Example 7 3.26 26.99 269.7 Example 8 3.39 22.98 237.4 Example 9 3.24 23.67 240.8 Example 10 3.32 26.74 248.8 Example 11 3.30 25.41 244.6 Example 12 3.31 24.76 245.1 Example 13 3.22 27.13 266.9 Example 14 3.19 28.04 277.6 Example 15 3.35 23.94 241.4 Comparative Example 1 4.80 5.00 5.0 Comparative Example 2 4.27 19.76 48.0 Comparative Example 3 3.66 20.01 227.3 Comparative Example 4 4.00 16.31 110.8 Comparative Example 5 4.31 16.34 210.8 Comparative Example 6 4.08 13.11 111.5

[0228] It can be seen from the data in the above table that for the organic electroluminescent host material developed in the present invention, through the mutual cooperation and synergistic effect of compound N and compound M, the carrier injection efficiency can be significantly improved, the energy level difference between layers can be reduced, the electron and hole transport rates can be balanced, and the efficiency of the organic electroluminescent device can be effectively improved and the lifespan of the organic electroluminescent device can be extended. When the organic electroluminescent material is used as the organic functional layer material, the first host material and the second host material act synergistically, enabling the device to have a low driving voltage (below 3.43 V), a high current efficiency (above 22.77 Cd / A), and a high lifespan (above 230 h).

[0229] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An organic electroluminescent material, characterized in that, Comprising a plurality of host materials, the plurality of host materials comprising a first host material and a second host material, the first host material comprising a compound represented by formula (I): wherein, X is selected from O, S, Se, NAr, CR 6 R 7 ; R 1 is —L 1 Ar 1 ,R 2 is —L 2 Ar 2 ,R 3 is —L 3 Ar 3 ; Ar is selected from hydrogen, deuterium, and aryl groups having 6 to 30 carbon atoms; R 6 ,R 7 each independently selected from a hydrogen atom, an alkyl group having 1 to 2 carbon atoms, and a phenyl group, L 1 ,L 2 ,L 3 Each is independently selected from a linking group, an arylene group having 6 to 30 carbon atoms; Ar 1 ,Ar 2 ,Ar 3 At least one of them is a structure represented by formula (II), and the others are each independently selected from hydrogen, deuterium, protium, and tritium. R 4 is —L 4 Ar 4 ,R 5 is —L 5 Ar 5 , wherein, L 4 , L 5 are each independently selected from a linking group, an arylene group having 6 to 30 carbon atoms; Ar 4 -Ar 5 Each independently selected from substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; The second host material comprises a compound represented by formula (2): Wherein, L is selected from a linking bond; Ar 8 ,Ar 9 each independently selected from substituted or unsubstituted C6-C30 aryl, C3-C30 heteroaryl; The substituents in the substituted aryl group having 6 to 30 carbon atoms and the substituted heteroaryl group having 3 to 30 carbon atoms are selected from one or a combination of two of deuterium, alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 30 carbon atoms, and heteroaryl groups having 3 to 30 carbon atoms; The mass ratio of the compound represented by formula (1) to the compound represented by formula (2) is 4:6 - 6:

4.

2. The organic electroluminescent material according to claim 1, wherein The compound represented by formula (2) has any one of the following structures:

3. The organic electroluminescent material according to claim 1 or 2, characterized in that, Ar 4 and Ar 5 each independently selected from the following substituted or unsubstituted groups: phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, triphenylene, -yl, dibenzofuranyl, benzonaphthofuranyl, dibenzothiophenyl, dibenzoselenophenyl, triphenylene, dimethylfluorenyl, spirobifluorenyl, fluoranthenyl, carbazolyl, phenylcarbazolyl, diphenylfluorenyl, benzyldimethylfluorenyl, benzodiphenylfluorenyl, benzospirobifluorenyl, pyridyl, pyrimidinyl, triazinyl.

4. The organic electroluminescent material according to claim 1, wherein Ar is selected from phenyl, naphthyl, biphenyl, terphenyl, triphenylene, anthryl, dibenzofuranyl, dibenzothiophenyl.

5. The organic electroluminescent material according to claim 1, wherein The L 1 , L 2 , L 3 is a single bond, Ar 1 , Ar 2 , Ar 3 are each independently selected from hydrogen, deuterium, and halogen.

6. The organic electroluminescent material according to claim 1, wherein The Ar 4 , Ar 5 are each independently selected from the structures represented by the following formulas (III) and (IV): R T1 -R T6 Each independently selected from hydrogen, deuterium, C1-C30 alkyl, unsubstituted C6-C30 aryl, unsubstituted C3-C30 heteroaryl; or, any two adjacent ones substituted by the same phenyl group are fused into a ring A of C6-C23, Y is selected from O and S.

7. The organic electroluminescent material according to claim 6, characterized in that, Ring A is selected from unsubstituted phenyl, unsubstituted naphthyl, and unsubstituted phenanthryl; When there are multiple Rs T1 -R T6 At this time, R T1 -R T6 are each independent of one another and can be the same or different.

8. The organic electroluminescent material according to claim 1, wherein The compound represented by formula (I) has any one of the structures shown in Chemical Formula 1-1 to Chemical Formula 1-17:

9. The organic electroluminescent material according to claim 8, wherein The compound represented by formula (1) has any one of the following structures:

10. Use of the organic electroluminescent material according to any one of claims 1-9 in the preparation of an optical device.

11. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode and a cathode, and an organic layer disposed between the anode and the cathode, the organic layer including the organic electroluminescent material according to any one of claims 1-9.

12. The organic electroluminescent device according to claim 11, wherein The light-emitting layer in the organic layer includes the organic electroluminescent material according to any one of claims 1-9.

13. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes the organic electroluminescent device according to claim 11 or 12.

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