A compound and its application, and an organic electroluminescent device containing the same

Abstract

The present invention provides a compound and its application, and an organic electroluminescent device containing the compound, wherein the compound has a structure of formula (I), and the compound is used as a material of a light-emitting layer in the organic electroluminescent device; the organic electroluminescent device comprises a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer contains any one or a combination of at least two of the compounds. The compound provided by the present invention can further reduce the efficiency roll-off of the device and extend the device life while ensuring a suitable driving voltage.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, and in particular to a compound and application thereof, and an organic electroluminescence device containing the compound. Background Art

[0002] Organic light-emitting diodes (OLEDs) for display and lighting have attracted widespread attention due to their many advantages, such as self-luminescence, wide viewing angle, fast response time, low power consumption, large size and flexibility. The device structure of OLEDs is often composed of multiple functional layers such as transmission layer, barrier layer and light-emitting layer, among which the dye used for light emission directly determines the color purity of the device.

[0003] Although the luminous efficiency of fluorescent materials is low and the power consumption is higher than that of phosphorescent materials, they have a longer lifespan and better color purity. At present, blue light devices are still mainly fluorescent devices. Phosphorescent materials contain heavy metals (such as iridium, platinum, etc.) and can use triplet excitons to emit light, so they have higher efficiency and low power consumption. However, their high price is not conducive to the further development of industrialization. In the current commercial organic electroluminescent device structure, blue fluorescence is generally used in combination with red and green phosphorescent materials.

[0004] Recently, researchers from Kansai University in Japan and other institutions have reported a metal-free TADF (Thermally Activated Delayed Fluorescence) resonant organic material DABNA-1 (Adv. Mater. 2016, 28, 2777–2781 J. Mater. Chem. C, 2019, 7, 3082-3089). This type of compound has a large aromatic skeleton and thus has a high fluorescence quantum yield. At the same time, due to the presence of B and N atoms, this type of compound exhibits a certain resonance effect. This type of compound exhibits the advantages of a narrow spectrum and high color purity. However, due to the large difference in energy levels between its singlet and triplet states, its reverse intersystem crossing is slow. In addition, its lowest unoccupied orbital energy level is deep, and excitons are easily directly recombined on the dye, resulting in severe efficiency roll-off and a short device life.

[0005]

[0006] Existing organic electroluminescent materials still have a lot of room for improvement in luminescent performance. The industry urgently needs to develop new luminescent material systems to meet commercial needs. Therefore, more types of luminescent materials with higher performance need to be developed. Summary of the invention

[0007] In view of the deficiencies of the prior art, the object of the present invention is to provide a compound having a structure of formula (I):

[0008]

[0009] In formula (I), A, B and C each independently represent an aromatic ring or a heteroaromatic ring;

[0010] In formula (I), R a , R b and R n Each independently represents a single substituent to the maximum permissible substituent, and is independently selected from deuterated or undeuterated hydrogen, deuterated or undeuterated C1-C12 alkyl, deuterated or undeuterated C1-C12 alkoxy, halogen, cyano, nitro, hydroxyl, silane, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0011] In formula (I), Ar 1 and Ar 2 Each is independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group;

[0012] In formula (I), Ar 1 With R a or ring A is connected to form a ring or not;

[0013] In formula (I), Ar 2 With R b or ring B is connected to form a ring or not;

[0014] In formula (I), R a , R b , R n ,Ar 1 and Ar 2 At least one of them is a structure shown in formula (A):

[0015]

[0016] In formula (A), R 1 and R 2 Each is independently selected from a deuterium atom, a C1-C12 chain alkyl group, a C3-C12 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group,

[0017] In formula (A), X is CR 3 R 4 , O or S, wherein R 3 and R 4Each is independently selected from one of C1-C12 chain alkyl, C3-C12 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl,

[0018] In formula (A), n is 0 or 1; when n is 0, it refers to R 1 and R 2 They do not form a cycle with each other; when n is 1, the meaning is R 1 and R 2 form a circle with each other;

[0019] The substituted substituent is selected from any one of deuterium, halogen, C1-C10 alkyl, C2-C10 alkenyl, C1-C6 alkoxy, C6-C30 monocyclic aromatic hydrocarbon or condensed aromatic hydrocarbon group, C3-C30 monocyclic heteroaromatic hydrocarbon or condensed heteroaromatic hydrocarbon group.

[0020] The C5~C20 can be C5, C6, C7, C8, C9, C10, C11, C12, C14, C16, C18, C20, etc.

[0021] The C4~C20 can be C4, C5, C6, C7, C8, C9, C10, C11, C12, C14, C16, C18, C20, etc.

[0022] The C1~C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.

[0023] The C2~C10 can be C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.

[0024] The C1~C6 can be C1, C2, C3, C4, C5, C6, etc.

[0025] The C1~C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, etc.

[0026] The C3~C10 can be C3, C4, C5, C6, C7, C8, C9, C10, etc.

[0027] The C6~C30 can be C6, C8, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, etc.

[0028] The C9~C30 can be C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, etc.

[0029] The C3~C30 can be C3, C4, C6, C8, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, etc.

[0030] The C5~C30 can be C5, C8, C10, C12, C14, C16, C18, C20, C22, C24, C26, C28, C30, etc.

[0031] In the present invention, the maximum permissible substituents refer to the maximum number of substituents under the premise that the substituted group meets the requirements of the chemical bond. For example, the number of R that can be connected to ring 1 is a The number of can be one or more. For example, if ring A is selected from a benzene ring, it can only have the maximum allowed substituents (i.e. 4).

[0032] The present invention uses a BN resonance type compound as a parent ring structure when designing a compound, and the compound has at least one structure of formula A, so that when the compound is used as a light-emitting material in an organic electroluminescent device, the efficiency roll-off of the device can be further reduced and the device life can be extended while ensuring a suitable driving voltage.

[0033] Among them, the BN resonance type compound has a strong rigid structure, which effectively reduces the non-radiative transition energy loss caused by molecular vibration and rotation, and thus has a higher fluorescence quantum yield. In addition, the resonance effect makes the HOMO and LUMO orbits of the entire molecule separated significantly, showing the characteristics of thermally activated delayed fluorescence; in addition, at least one of the formula A structures in the compound is replaced by an alkyl group to further increase the molecular spacing, reduce the quenching caused by molecular stacking, and the introduction of heavy atoms can further reduce the non-radiative transition of the molecule, further reduce the efficiency roll-off, and further improve the life of the device.

[0034] The compound of the present invention has a long service life while ensuring that the device has a suitable driving voltage and efficiency. It is not only suitable for use as a luminescent material in an organic electroluminescent device, but can also be applied to technical fields such as optical sensors, solar cells, lighting elements, organic thin film transistors, organic field effect transistors, organic thin film solar cells, information labels, etc.

[0035] Preferably, A, B and C each independently represent any one of a C5-C10 monocyclic aromatic ring or a condensed aromatic ring, a C4-C10 monocyclic heterocyclic ring or a condensed heterocyclic ring;

[0036] Preferably, A, B and C are each independently selected from any one of a benzene ring, a naphthalene ring or a fluorene ring.

[0037] Preferably, the compound has the structure of formula (II):

[0038]

[0039] In formula (II), R a , R b , R n ,Ar 1 and Ar 2 Each independently has the same limitations as above;

[0040] In formula (II), Ar 1 Connected to ring 1 to form a ring or not connected to ring 1 to form a ring;

[0041] In formula (II), Ar 2 Connected to ring 2 to form a ring or not connected to ring 2 to form a ring;

[0042] In formula (II), R a , R b , R n ,Ar 1 and Ar 2 At least one of the compounds has a structure as shown in formula A.

[0043] Preferably, the compound has any one of the structures of formula (3-1) to (3-3):

[0044]

[0045] In formula (3-1)-(3-3), R a , R b and R n Each independently has the same limitations as above;

[0046] In formula (3-1)-(3-3), R d , R c , R d’ and R c’ Each independently represents a monosubstituted to maximum permissible substituent, and each independently is selected from one of hydrogen, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C10 alkoxy, halogen, cyano, nitro, hydroxyl, silane, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

[0047] The substituted substituent is selected from any one of halogen, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C6 alkoxy or thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aromatic hydrocarbon or condensed aromatic hydrocarbon group, C3-C30 monocyclic heteroaromatic hydrocarbon or condensed heteroaromatic hydrocarbon group;

[0048] In formula (3-1), R d , R c , R a , R b and R n At least one of them is a structure shown in formula A;

[0049] In formula (3-2), R d’ , R c , R a , R b and R n At least one of them is a structure shown in formula A;

[0050] In formula (3-3), R d’ , R c’ , R a , R b and R n At least one of the compounds has a structure as shown in formula A.

[0051] Preferably, the R a , R b , R n , R d and R c wherein each is independently selected from any one of hydrogen, C1-C12 chain alkyl, and C3-C12 cycloalkyl.

[0052] Preferably, the R a , R b and R n Each is independently selected from any one of hydrogen, C1-C12 chain alkyl, and C3-C12 cycloalkyl.

[0053] Preferably, the C1-C12 chain alkyl and C3-C12 cycloalkyl are selected from any one of the following groups:

[0054]

[0055] Preferably, n is 0.

[0056] Preferably, the R 1 and R 2 Each is independently selected from any one of a C1-C12 chain alkyl group and a C3-C12 cycloalkyl group.

[0057] Preferably, the R 1 and R 2 Each is independently selected from any one of a C1-C8 chain alkyl group and a C3-C8 cycloalkyl group.

[0058] Preferably, the R 1 and R 2 Each is independently selected from any one of a deuterium atom, a methyl group or an ethyl group, preferably a methyl group.

[0059] Preferably, the compound is selected from any one of the following structures M1-M140:

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] A second object of the present invention is to provide an application of the compound described in the first object, wherein the application is as a material for a light-emitting layer in an organic electroluminescent device.

[0068] The third object of the present invention is to provide an organic electroluminescent device, comprising a first electrode, a second electrode and an organic layer located between the first electrode and the second electrode, wherein the organic layer comprises any one or a combination of at least two of the compounds described in one of the objects.

[0069] The organic electroluminescent device provided by the present invention includes a first electrode, a second electrode, and an organic material layer located between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0070] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0071] The first electrode can be formed by sputtering or depositing a material used as the first electrode on the substrate. When the first electrode is used as an anode, indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO 2 ), zinc oxide (ZnO) and other oxide transparent conductive materials and any combination thereof. When the first electrode is used as a cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and the like and any combination thereof can be used.

[0072] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0073] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) of a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multi-layer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0074] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-34 below; or any combination thereof.

[0075]

[0076]

[0077]

[0078] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-34, or one or more compounds of HI-1 to HI-3 described below; or one or more compounds of HT-1 to HT-34 can be doped with one or more compounds of HI-1 to HI-3 described below.

[0079]

[0080] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit light of different wavelength spectra, and may also include a host material (Host). The light-emitting layer may be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors may be arranged in a plane according to a pixel pattern, or may be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they may be separated from each other or may be connected to each other. The light-emitting layer may also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0081] According to different technologies, the light-emitting layer material can be made of different materials such as fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescent materials. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0082] In one aspect of the present invention, the light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent host material of the light-emitting layer can be selected from, but not limited to, one or more combinations of BFH-1 to BFH-17 listed below.

[0083]

[0084]

[0085] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be an electron transport layer (ETL) of a single-layer structure, including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0086] In a specific example, the electron transport layer material can be selected from but not limited to one or more combinations of ET-1 to ET-57 listed below.

[0087]

[0088]

[0089]

[0090] The device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following compounds:

[0091] LiQ, LiF, NaCl, CsF, Li 2 O、Cs 2 CO 3 ,BaO,Na,Li,Ca.

[0092] Compared with the prior art, the technical progress achieved by the present invention is:

[0093] The compound provided by the present invention uses a BN resonance type compound as a parent ring structure, wherein the BN resonance type compound has a strong rigid structure, effectively reduces the non-radiative transition energy loss caused by molecular vibration, rotation, etc., and thus has a higher fluorescence quantum yield. In addition, the resonance effect makes the HOMO and LUMO orbits of the entire molecule separated significantly, showing the characteristics of thermally activated delayed fluorescence; in addition, at least one structure of formula A in the compound is replaced by an alkyl group so that the molecular spacing is further increased, reducing the quenching caused by molecular stacking, and the introduction of heavy atoms can further reduce the non-radiative transition of the molecule, further reduce the efficiency roll-off, and further improve the life of the device; when the compound is used as a luminescent material in an organic electroluminescent device, the efficiency roll-off of the device can be further reduced, and the device life can be extended under the premise of ensuring a suitable driving voltage. DETAILED DESCRIPTION

[0094] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0095] The compounds of the synthesis methods not mentioned in the present invention are all raw materials obtained through commercial channels. The solvents and reagents used in the present invention, such as dichloromethane, petroleum ether, ethanol, tetrahydrofuran, N, N-dimethylacetamide, anhydrous magnesium sulfate, carbazole, benzimidazole and other chemical reagents, can be purchased from the domestic chemical product market, such as Sinopharm Group Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, Bailingwei Reagent Company, etc.

[0096] The present invention will be described in detail below with reference to a number of specific embodiments. The compounds of the embodiments of the present invention can be synthesized with reference to the specific synthesis examples shown below, but it should be noted that obtaining the compound is not limited to the synthesis method and raw materials used in the present invention, and those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. The compounds for which the synthesis method is not mentioned in the present invention are raw materials obtained from commercial channels, or are prepared by these raw materials according to known methods.

[0097] The analysis and detection of the intermediates and compounds in the present invention were performed using an ABSCIEX mass spectrometer (4000QTRAP).

[0098] The general formula of the preparation example can be any one of the following three general formulas:

[0099]

[0100]

[0101] In a specific embodiment, the preparation and synthesis can be carried out according to one of the above routes. The selection of the specific route can be selected by those skilled in the art according to actual needs, and is not specifically limited here; wherein, R a , R b , R c , R d and R n Has the same range of options as above.

[0102] Preparation Example 1

[0103] Synthesis of compound M1:

[0104]

[0105] (1) Preparation of compound M1-1:

[0106] At room temperature, 1,3-dibromo-5(isopropyl-2-d)benzene (27.7 g, 100 mmol), diphenylamine (41.7 g, 250 mmol), tris(dibenzylidene-BASE acetone)dipalladium (Pd 2 (dba) 3 )(0.92g, 1mmol), 2-dicyclohexylphosphino-2,6-dimethoxybiphenyl (s-Phos) (0.82g, 2mmol), sodium tert-butoxide (24g, 250mmol), xylene (500ml) were added to a 1L single-mouth bottle, replaced with nitrogen three times, heated to 130°C and reacted overnight. The reaction solution was cooled to room temperature, extracted with ethyl acetate, washed with a large amount of water, and the organic phase was dried and concentrated for column chromatography (PE: DCM = 25:1) to obtain 38g of crude product, which was heated and washed with n-hexane to obtain 36.4g of white solid, with a yield of 79.9%. The molecular ion mass determined by mass spectrometry: 455.28 (theoretical value: 455.25).

[0107] (2) Preparation of Compound M1

[0108] M1-1 (4.6 g, 10 mmol) was added to a 250 ml three-necked flask, and p-tert-butylbenzene (80 ml) was added. After stirring for 20 minutes, the reaction system was cooled to -20 ° C, and then 15 mmol of tert-butyl lithium was added. The temperature was maintained at low temperature and continued to stir for 30 minutes. Then the temperature was gradually raised to 90 ° C and the heating was continued for 3 hours. Finally, the temperature of the reaction system was lowered to -20 ° C again, and boron tribromide (5.1 g, 20 mmol) was added under nitrogen protection. After stirring for 30 minutes, diisopropylethylamine (13 g, 80 mmol) was added. Finally, the reaction system was heated to 110 ° C and reacted for 12 hours. After the reaction was cooled to room temperature, the organic phase was decompressed and dried. Ethyl acetate (200 ml) was extracted three times, and the organic phases were combined and dried over anhydrous sodium sulfate. The organic phase was mixed with silica gel and concentrated, and column chromatography (PE: DCM = 100: 1) was used to obtain 1.3 g of crude product, which was recrystallized from toluene / n-hexane to obtain 0.66 g of yellow solid, with a yield of 14.2%. The molecular ion mass determined by mass spectrometry was: 463.20 (theoretical value: 463.23).

[0109] Preparation Example 2

[0110] The only difference from Preparation Example 1 is that diphenylamine is replaced by an equal molar amount of di(4-(methyl-d3))aniline to obtain product M3. Molecular ion mass determined by mass spectrometry: 531.35 (theoretical value: 531.37).

[0111] Preparation Example 3

[0112] Product M11.

[0113] The only difference from Preparation Example 1 is that diphenylamine is replaced by an equal molar amount of dibenzidine to obtain product M11. The molecular ion mass determined by mass spectrometry is 767.35 (theoretical value: 767.36).

[0114] Preparation Example 4

[0115] Synthesis of compound M53:

[0116]

[0117] (1) Preparation of compound M53-1:

[0118] At room temperature, tribromobenzene (31.2 g, 100 mmol), di(4-(isopropyl-2-d)phenylamine (81.7 g, 320 mmol), Pd 2 (dba) 3(2.8g, 3mmol), s-Phos (1.2g, 3mmol), sodium tert-butoxide (33.6g, 350mmol), xylene (1200ml) were added to a 2L single-mouth bottle, replaced with nitrogen three times, heated to 130°C and reacted overnight. The reaction solution was cooled to room temperature, extracted with ethyl acetate, washed with a large amount of water, and the organic phase was dried and concentrated and subjected to column chromatography (PE: DCM = 30: 1) to obtain 56.2g of white solid, with a yield of 67.1%. The molecular ion mass determined by mass spectrometry was 837.58 (theoretical value: 837.59).

[0119] (2) Preparation of Compound M53

[0120] M53-1 (8.4 g, 10 mmol) was added to a 500 ml three-necked flask, and p-tert-butylbenzene (150 ml) was added. After stirring for 20 minutes, the reaction system was cooled to -20 ° C, and then 15 mmol of tert-butyl lithium was added. The temperature was maintained at low temperature and continued to stir for 30 minutes. Then the temperature was gradually raised to 90 ° C and continued to heat for 3 hours. Finally, the temperature of the reaction system was lowered to -20 ° C again, and boron tribromide (5.1 g, 20 mmol) was added under nitrogen protection. After stirring for 30 minutes, diisopropylethylamine (13 g, 80 mmol) was added. Finally, the reaction system was heated to 110 ° C and reacted for 12 hours. After the reaction was cooled to room temperature, the organic phase was decompressed and dried. Ethyl acetate (200 ml) was extracted three times, and the organic phases were combined and dried over anhydrous sodium sulfate. The organic phase was mixed with silica gel and concentrated, and column chromatography (PE: DCM = 40: 1) was used to obtain 2.3 g of crude product, which was recrystallized from toluene / n-hexane to obtain 1.1 g of yellow solid with a yield of 13.0%. The molecular ion mass determined by mass spectrometry was: 845.57 (theoretical value: 845.57).

[0121] Preparation Example 5

[0122] Synthesis of compound M69:

[0123]

[0124] (1) Preparation of compound M69-1:

[0125] 3,6-di(isopropyl-2-d)carbazole (21.5g, 85mmol), 2-bromo-1,3-difluorobenzene (7.7g, 40mmol), cesium carbonate (32.6g, 100mmol), N,N-dimethylformamide (350ml) were added to a 500mL single-mouth bottle at room temperature. After nitrogen replacement for 3 times, the mixture was heated at 130°C for overnight reaction. After the reaction stopped, 500ml of water was added and stirred for 10min after cooling to room temperature. A large amount of white solid precipitated, which was filtered by suction. The filter cake was boiled and washed with ethanol for 2h, cooled and filtered by suction to obtain 21.8g of white solid product with a yield of 82.8%. The molecular ion mass determined by mass spectrometry was 658.27 (theoretical value: 658.29).

[0126] (2) Preparation of Compound M69

[0127] M69-1 (6.6 g, 10 mmol) was added to a 500 ml three-necked flask, and p-tert-butylbenzene (100 ml) was added. After stirring for 20 minutes, the reaction system was cooled to -20 ° C, and then 15 mmol of tert-butyl lithium was added. The temperature was maintained at low temperature and continued to stir for 30 minutes. Then the temperature was gradually raised to 90 ° C and continued to heat for 3 hours. Finally, the temperature of the reaction system was lowered to -20 ° C again, and boron tribromide (5.1 g, 20 mmol) was added under nitrogen protection. After stirring for 30 minutes, diisopropylethylamine (13 g, 80 mmol) was added. Finally, the reaction system was heated to 110 ° C and reacted for 12 hours. After the reaction was cooled to room temperature, the organic phase was decompressed and dried. Ethyl acetate (200 ml) was extracted three times, and the organic phases were combined and dried over anhydrous sodium sulfate. The organic phase was mixed with silica gel and concentrated, and column chromatography (PE: DCM = 40: 1) was used to obtain 2.4 g of crude product, which was recrystallized from toluene / n-hexane to obtain 0.8 g of yellow solid, with a yield of 16.5%. The molecular ion mass determined by mass spectrometry was: 588.37 (theoretical value: 588.36).

[0128] Preparation Example 6

[0129] The only difference from Preparation Example 5 is that 2-bromo-1,3-difluorobenzene is replaced by an equal molar amount of 3,5-dibromo-tert-butylbenzene to obtain product M76. Molecular ion mass determined by mass spectrometry: 644.43 (theoretical value: 644.42).

[0130] Preparation Example 7

[0131]

[0132] (1) Preparation of compound M97-1:

[0133] 3,6-di(isopropyl-2-d)carbazole (21.5 g, 85 mmol), 5-bromo-2-chloro-1,3-difluorobenzene (9.0 g, 40 mmol), cesium carbonate (32.6 g, 100 mmol), N,N-dimethylformamide (350 ml) were added to a 500 mL single-mouth bottle at room temperature. After nitrogen replacement for 3 times, the mixture was heated at 130 °C for overnight reaction. After the reaction was stopped, 500 ml of water was added and stirred for 10 min after cooling to room temperature. A large amount of white solid precipitated, which was filtered by suction. The filter cake was boiled and washed with ethanol for 2 h, cooled and filtered by suction to obtain 25.6 g of white solid product with a yield of 92.4%. The molecular ion mass determined by mass spectrometry was 692.23 (theoretical value: 692.25).

[0134] (2) Preparation of compound M97-2:

[0135] At room temperature, M97-1 (13.8 g, 20 mmol), o-fluorophenylboric acid (3.1 g, 22 mmol), anhydrous potassium carbonate (4.14 g, 30 mmol), 15 mL of water and 1,4-dioxane (350 ml) were added to a 500 mL single-mouth bottle. After nitrogen replacement 3 times, 800 mg of tetrakis triphenylphosphine palladium was added and heated at 120 ° C for overnight reaction. After the reaction stopped and cooled to room temperature, the organic solvent of the reaction system was dried, extracted with dichloromethane, and washed with a large amount of water. The organic phases were combined, dried and concentrated, and then column chromatography was performed to obtain 11.2 g of a white solid product with a yield of 79.0%. The molecular ion mass determined by mass spectrometry was 708.32 (theoretical value: 708.36).

[0136] (3) Preparation of Compound M97

[0137] M97 (7.1 g, 10 mmol) was added to a 500 ml three-necked flask, and p-tert-butylbenzene (100 ml) was added. After stirring for 20 minutes, the reaction system was cooled to -20 ° C, and then 15 mmol of tert-butyl lithium was added. The temperature was maintained at low temperature and continued to stir for 30 minutes. Then the temperature was gradually raised to 90 ° C and continued to heat for 3 hours. Finally, the temperature of the reaction system was lowered to -20 ° C again, and boron tribromide (5.1 g, 20 mmol) was added under nitrogen protection. After stirring for 30 minutes, diisopropylethylamine (13 g, 80 mmol) was added. Finally, the reaction system was heated to 110 ° C and reacted for 12 hours. After the reaction was cooled to room temperature, the organic phase was decompressed and dried. Ethyl acetate (200 ml) was extracted three times, and the organic phases were combined and dried over anhydrous sodium sulfate. The organic phase was mixed with silica gel and concentrated, and column chromatography (PE: DCM = 40: 1) was used to obtain 4.1 g of crude product, which was recrystallized from toluene / n-hexane to obtain 2.3 g of yellow solid, with a yield of 33.7%. The molecular ion mass determined by mass spectrometry was: 682.37 (theoretical value: 682.38).

[0138] Preparation Example 8

[0139] The only difference from Preparation Example 7 is that o-fluorophenylboric acid is replaced by an equal molar amount of 2,6-difluorophenylboric acid to obtain product M99. Molecular ion mass determined by mass spectrometry: 700.35 (theoretical value: 700.37).

[0140] Example 1

[0141] This embodiment provides an organic electroluminescent device, and the preparation process thereof is as follows:

[0142] A glass plate coated with a transparent conductive layer of ITO (thickness 150 nm) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0143] Place the glass substrate with the anode in a vacuum chamber and evacuate the chamber to a vacuum of less than 1×10 -5 Pa, HI-2 and HT-4 were vacuum evaporated on the above anode layer as hole injection layer and hole transport layer, respectively, with an evaporation rate of 0.1 nm / s and an evaporation film thickness of 10 nm and 40 nm, respectively;

[0144] Vacuum evaporation of "BFH-4:M1 (30nm, 5%wt)" on the hole transport layer as the light-emitting layer of the organic electroluminescent device, the evaporation rate is 0.1nm / s, and the total evaporation film thickness is 30nm; "5%wt" refers to the doping ratio of the dye, that is, the mass ratio of the main material BFH-4 to M1 is 95:5;

[0145] The electron transport layer material ET-34 of the device is vacuum-deposited on the light-emitting layer, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 30 nm;

[0146] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0147] Make it have the following structure:

[0148] ITO(150nm) / HI-2(10nm) / HT-4(40nm) / BFH-4:M1(30nm, 5wt%) / ET-34(30nm) / LiF(1nm) / Al(150nm).

[0149] Example 2

[0150] The difference from Example 1 is that M1 is replaced by M3.

[0151] Example 3

[0152] The difference from Example 1 is that M1 is replaced by M11.

[0153] Example 4

[0154] The difference from Example 1 is that M1 is replaced by M53.

[0155] Example 5

[0156] The difference from Example 1 is that M1 is replaced by M69.

[0157] Example 6

[0158] The difference from Example 1 is that M1 is replaced by M76.

[0159] Example 7

[0160] The difference from Example 1 is that M1 is replaced by M97.

[0161] Example 8

[0162] The difference from Example 1 is that M1 is replaced by M99.

[0163] Example 9

[0164] The difference from Example 1 is that M1 is replaced by M111.

[0165] Example 10

[0166] The difference from Example 1 is that M1 is replaced by M114.

[0167] Comparative Example 1

[0168] The difference from Example 1 is that M1 is replaced by tBuDABNA.

[0169] Comparative Example 2

[0170] The difference from Example 1 is that M1 is replaced by R-1.

[0171]

[0172] Performance Test:

[0173] At the same brightness, a digital source meter and a brightness meter were used to measure the driving voltage and current efficiency of the organic electroluminescent devices prepared in the examples and comparative examples, as well as the life of the devices. Specifically, the voltage was increased at a rate of 0.1 V per second, and the brightness of the organic electroluminescent device was measured when it reached 1000 cd / m 2The voltage at which the light is on is the driving voltage, and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency; the life test of LT95 is as follows: use a brightness meter at 1000cd / m 2 At the same brightness, the current is kept constant and the brightness of the organic electroluminescent device is measured to drop to 950cd / m 2 The time in hours.

[0174] The performance test results are shown in Table 1:

[0175] Table 1

[0176]

[0177] As shown in Table 1, the maximum current efficiency of the organic electroluminescent device in the embodiment is ≥8.9cd / A, 1000cd / m 2 Lower voltage ≤5.6V, 1000cd / m 2 High efficiency ≥8.0cd / A, 1000cd / m 2 Lower lifespan ≥56h;

[0178] The luminescent material of the device in comparative example 1 was replaced with DABNA-1, and the maximum current efficiency and 2 The efficiency and lifespan are obviously deteriorated because the molecule has obvious non-radiative transitions such as vibration and rotation;

[0179] The luminescent material of the device in comparative example 2 was replaced with R-1, 1000 cd / m 2 The efficiency and lifetime are significantly deteriorated because the deuteration on the alkyl group is more conducive to reducing non-radiative transitions and improving the stability of the molecule.

[0180] The above results prove that when the compound provided by the present invention is used as the light-emitting layer material of an organic electroluminescent device, the efficiency and life of the device are improved, showing excellent device performance. This is because the compound of the present invention uses a BN conjugated system as a parent core, and in addition, at least one structure of formula A in the compound is provided, and the stability of the device is significantly improved, which is conducive to the practical application of the compound of the present invention.

[0181] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound, characterized in that The compound has the structure of formula (II): In formula (II), R a , R b and R n Each independently represents a single substituent to the maximum permissible substituent, and is independently selected from deuterated or undeuterated hydrogen, deuterated or undeuterated C1-C12 chain alkyl, deuterated or undeuterated C3-C12 cycloalkyl, deuterated or undeuterated C1-C10 alkoxy, halogen, cyano, nitro, silane, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl; In formula (II), Ar 1 and Ar 2 Each is independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group; In formula (II), Ar 1 With R a and / or ring 1 is connected to form a ring or not connected to form a ring; In formula (II), Ar 2 With R b and / or ring 2 is connected to form a ring or not connected to form a ring; In formula (II), R a , R b , R n ,Ar 1 and Ar 2 At least one of them is a structure shown in formula (A): In formula (A), R 1 and R 2 Each is independently selected from one of C1-C12 chain alkyl, C3-C12 cycloalkyl, and substituted or unsubstituted C6-C30 aryl, In formula (A), X is CR 3 R 4 , O or S, wherein R 3 and R 4 Each is independently selected from one of C1-C12 chain alkyl, C3-C12 cycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl, In formula (A), n is 0; The substituted substituent is selected from any one of halogen, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C6 alkoxy or thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aromatic hydrocarbon or condensed aromatic hydrocarbon group, C3-C30 monocyclic heteroaromatic hydrocarbon or condensed heteroaromatic hydrocarbon group.

2. The compound according to claim 1, characterized in that The compound has any one of the structures of formula (3-1) to (3-3): In formula (3-1)-(3-3), R a , R b and R n Each independently has the same definition as claim 1; In formula (3-1)-(3-3), R d , R c , R d’ and R c’ Each independently represents a monosubstituted to maximum permissible substituent, and each independently is selected from one of hydrogen, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C10 alkoxy, halogen, cyano, nitro, hydroxyl, silane, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl; The substituted substituent is selected from any one of halogen, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C6 alkoxy or thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aromatic hydrocarbon or condensed aromatic hydrocarbon group, C3-C30 monocyclic heteroaromatic hydrocarbon or condensed heteroaromatic hydrocarbon group; In formula (3-1), R d , R c , R a , R b and R n At least one of them is a structure shown in formula A; In formula (3-2), R d’ , R c , R a , R b and R n At least one of them is a structure shown in formula A; In formula (3-3), R d’ , R c’ , R a , R b and R n At least one of the compounds has a structure as shown in formula A.

3. The compound according to claim 2, characterized in that The R a , R b , R n , R d , R c , R d’ and R c’ wherein each is independently selected from any one of hydrogen, C1-C12 chain alkyl, and C3-C12 cycloalkyl.

4. The compound according to claim 1, characterized in that The R a , R b and R n Each is independently selected from any one of hydrogen, C1-C12 chain alkyl, and C3-C12 cycloalkyl.

5. The compound according to any one of claims 1 to 4, characterized in that The C1-C12 chain alkyl group and the C3-C12 cycloalkyl group are selected from any one of the following groups:

6. The compound according to claim 1, characterized in that The R 1 and R 2 Each is independently selected from any one of a C1-C12 chain alkyl group and a C3-C12 cycloalkyl group.

7. The compound according to claim 1, characterized in that The R 1 and R 2 Each is independently selected from any one of a C1-C8 chain alkyl group and a C3-C8 cycloalkyl group.

8. The compound according to claim 1, characterized in that The R 1 and R 2 Each is independently selected from any one of a methyl group and an ethyl group.

9. The compound according to claim 1, characterized in that The R 1 and R 2 It is methyl.

10. A compound, characterized in that The compound includes any one of the following structures:

11. A use of a compound according to any one of claims 1 to 10, characterized in that: The application is as a material for a light-emitting layer in an organic electroluminescent device.

12. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and an organic layer between the first electrode and the second electrode, wherein the organic layer contains the compound according to any one of claims 1 to 10.

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