A hexamethylbiphenyl derivative, its preparation method and application

Abstract

The present invention belongs to the technical field of organic optoelectronic materials, and specifically relates to a hexamethylbiphenyl derivative, its preparation method and application. The derivative has a structure shown in formula (1): X1, X2, X3, and X4 are the same or different and independently selected from a single bond, a carbon atom, a silicon atom, an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, a boron atom, a carbonyl group (-C=O-), a sulfone group (-SO2-), a sulfoxide group (-S=O-), a phosphine oxide group (-P=O-), an aryl group of C 6～18 or a heteroaryl group of C 5‑18 . The hexamethylbiphenyl derivative of the present invention has good thermal stability, film-forming properties and high luminous efficiency, and can be used to prepare electronic devices such as organic light-emitting devices, organic solar cells and organic field-effect transistors. #imgabs0#

Description

Technical Field

[0001] The present invention belongs to the technical field of organic optoelectronic materials, and particularly relates to a hexamethylbiphenyl derivative, a preparation method thereof, and an application thereof. Background Art

[0002] Organic optoelectronic materials have the characteristics of diverse structures, excellent properties, and relatively low synthesis and preparation costs, and are widely used and have great potential in optoelectronic devices such as organic light-emitting diodes (OLEDs).

[0003] In order to improve the performance of optoelectronic devices such as OLEDs and promote their large-scale industrialization process, various organic optoelectronic material systems with excellent properties have been developed in large numbers. However, the performance of optoelectronic devices, especially the lifetime and stability, still need to be further improved. As the core component of optoelectronic devices such as OLEDs, highly efficient and stable organic optoelectronic materials are urgently needed to be developed.

[0004] The thermal stability and film-forming quality of organic optoelectronic materials are important factors affecting the stability and efficiency of devices. High thermal stability can effectively inhibit the decomposition and crystallization of materials during device preparation and operation, while the ability to form high-quality amorphous films can improve the interfacial quality between adjacent layers in the device, thereby enhancing the optoelectronic performance and device lifetime of the device.

[0005] However, the current organic optoelectronic materials have relatively low thermal stability, and the ability to form amorphous films needs to be improved.

[0006] At the same time, for organic electroluminescent materials, the close packing between organic molecules easily leads to exciton quenching, exacerbates non-radiative transitions, and thus reduces the luminescence performance and stability of the materials and devices. Summary of the Invention

[0007] The present invention provides a hexamethylbiphenyl derivative having the structure shown in formula (1):

[0008]

[0009] Wherein: X 1 、X 2 、X 3 、X 4 are the same or different and independently selected from a single bond, a carbon atom, a silicon atom, an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, a boron atom, a carbonyl group (-C=O-), a sulfone group (-SO 2 -), a sulfoxide group (-S=O-), a phosphine oxide group (-P=O-), an aryl group of C 6～18 or a heteroaryl group of C 5-18 ;

[0010] Y 1 、Y 2 、Y 3, Y 4 identical or different and independently selected from a hydrogen atom, a halogen atom, a cyano group, C(=O)R 1 , -S(=O)R 1 , -S(=O) 2 R 1 , -P(=O)(R 1 ) 2 , -P(R 1 ) 2 , -N(R 1 ) 2 , -B(R 1 ) 2 , -O(R 1 ), -S(R 1 ), -Si(R 1 ) 3 , unsubstituted or optionally substituted by one, two or more fluorine atom-substituted C 1～12 alkyl, unsubstituted or optionally substituted by one, two or more fluorine atom-substituted cycloalkyl, unsubstituted or optionally substituted by one, two or more R' 1 group-substituted C 6～60 aryl, unsubstituted or optionally substituted by one, two or more R' 1 group-substituted C 5～60 heteroaryl;

[0011] R 1 is selected from a hydrogen atom, a halogen atom, a cyano group, unsubstituted or optionally substituted by one, two or more fluorine atom-substituted C 1～12 alkyl, unsubstituted or optionally substituted by one, two or more fluorine atom-substituted cycloalkyl, unsubstituted or optionally substituted by one, two or more R 2 group-substituted C 6～60 aryl, unsubstituted or optionally substituted by one, two or more R 2 group-substituted C 5～60 heteroaryl;

[0012] R' 1 is selected from a halogen atom, a cyano group, unsubstituted or optionally substituted by one, two or more fluorine atom-substituted C 1～12 alkyl, unsubstituted or optionally substituted by one, two or more fluorine atom-substituted cycloalkyl, unsubstituted or optionally substituted by one, two or more R 2 group-substituted C 6～60 aryl, unsubstituted or optionally substituted by one, two or more R 2 group-substituted C 5～60 heteroaryl;

[0013] R 2Each independently selected from a halogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 60 carbon atoms, a heteroaryl group having 5 to 60 ring atoms;

[0014] m 1 , m 2 , m 3 , m 4 Each independently selected from any integer from 1 to 5, for example 1, 2, 3, 4 or 5.

[0015] According to an embodiment of the present invention, the Y 1 , Y 2 , Y 3 , Y 4 are the same or different and each independently selected from unsubstituted, a C 1～10 alkyl group substituted with one, two or more fluorine atoms, a cycloalkyl group substituted with one, two or more fluorine atoms, an aryl group of C 1 unsubstituted or optionally substituted with one, two or more R’ 6～40 groups, a heteroaryl group of C 1 unsubstituted or optionally substituted with one, two or more R’ 5～40 groups, where the definition of R’ 1 is the same as above.

[0016] Preferably, the Y 1 , Y 2 , Y 3 , Y 4 are the same or different and each independently selected from unsubstituted or optionally substituted with one, two or more fluorine atoms of a C 1～8 alkyl group, a cycloalkyl group unsubstituted or optionally substituted with one, two or more fluorine atoms, an aryl group of C 1 unsubstituted or optionally substituted with one, two or more R’ 6～20 groups, a heteroaryl group of C 1 unsubstituted or optionally substituted with one, two or more R’ 5～20 groups, where the definition of R’ 1 is the same as above.

[0017] More preferably, the Y 1 , Y 2 , Y 3 , Y 4 are the same or different and each independently selected from unsubstituted or optionally substituted with one, two or more fluorine atoms of a C 1～6 alkyl group, a cycloalkyl group unsubstituted or optionally substituted with one, two or more fluorine atoms, an aryl group of C 1 unsubstituted or optionally substituted with one, two or more R’6～12 aryl, unsubstituted or optionally substituted by one or more R’ 1 groups, and C 5～12 heteroaryl, where R’ 1 is as defined above.

[0018] Preferably, the R 1 is selected from C 1～10 alkyl which is unsubstituted or substituted by one, two or more fluorine atoms, cycloalkyl which is unsubstituted or substituted by one, two or more fluorine atoms, C 2 aryl which is unsubstituted or optionally substituted by one, two or more R 6～40 groups, and C 2 heteroaryl which is unsubstituted or optionally substituted by one, two or more R 5～40 groups, where R 2 is as defined above.

[0019] Preferably, the R 1 is selected from C 1～8 alkyl which is unsubstituted or substituted by one, two or more fluorine atoms, cycloalkyl which is unsubstituted or substituted by one, two or more fluorine atoms, C 2 aryl which is unsubstituted or optionally substituted by one, two or more R 6～20 groups, and C 2 heteroaryl which is unsubstituted or optionally substituted by one, two or more R 5～20 groups, where R 2 is as defined above.

[0020] More preferably, the R 1 is selected from C 1～6 alkyl which is unsubstituted or substituted by one, two or more fluorine atoms, cycloalkyl which is unsubstituted or substituted by one, two or more fluorine atoms, C 2 aryl which is unsubstituted or optionally substituted by one, two or more R 6～12 groups, and C 2 heteroaryl which is unsubstituted or optionally substituted by one or more R 5～12 groups, where R 2 is as defined above.

[0021] Preferably, the R’ 1 is selected from C 1～10 alkyl which is unsubstituted or substituted by one, two or more fluorine atoms, cycloalkyl which is unsubstituted or substituted by one, two or more fluorine atoms, C 2 aryl which is unsubstituted or optionally substituted by one, two or more R 6～40 groups, and C 2 heteroaryl which is unsubstituted or optionally substituted by one, two or more R5～40 The heteroaryl group, R 2 is defined as above.

[0022] Preferably, the R' 1 is selected from unsubstituted or C substituted by one, two or more fluorine atoms 1～8 alkyl, unsubstituted or cycloalkyl substituted by one, two or more fluorine atoms, unsubstituted or optionally substituted by one, two or more R 2 groups substituted C 6～20 aryl, unsubstituted or optionally substituted by one, two or more R 2 groups substituted C 5～20 heteroaryl, R 2 is defined as above.

[0023] More preferably, the R' 1 is selected from unsubstituted or C substituted by one, two or more fluorine atoms 1～6 alkyl, unsubstituted or cycloalkyl substituted by one, two or more fluorine atoms, unsubstituted or optionally substituted by one, two or more R 2 groups substituted C 6～12 aryl, unsubstituted or optionally substituted by one or more R 2 groups substituted C 5～12 heteroaryl, R 2 is defined as above.

[0024] According to an embodiment of the present invention, the X 1 , X 2 , X 3 , X 4 are the same or different and independently selected from each other as a single bond, a carbon atom, a silicon atom, an oxygen atom, a sulfur atom, a nitrogen atom, a phosphorus atom, a boron atom, a carbonyl C(=O), a sulfone group S(=O) 2 , a sulfoxide group S(=O), a phosphine oxide group P(=O), C 6-18 aryl or C 5-18 aromatic heterocyclic group.

[0025] Preferably, in the aromatic heterocyclic group, the heteroatoms include nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms and / or silicon atoms, preferably including nitrogen atoms, oxygen atoms and / or sulfur atoms; the number of heteroatoms is 1-10, preferably 1-5, for example 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0026] For example, the aryl includes phenyl, naphthyl, anthryl, phenanthryl, binaphthyl, tetraphenyl, pyrenyl, benzopyrenyl, triphenylenyl, acenaphthylenyl, fluorenyl or corresponding derivative groups.

[0027] For example, the heteroaryl group includes furyl, benzofuryl, thienyl, benzothienyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, pyrazolyl, triazolyl, tetrazolyl, triazinyl, pyridyl, pyrimidinyl, piperazinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinoxalinyl or a corresponding derivative group.

[0028] According to an embodiment of the present invention, the hexamethylbiphenyl structural unit in the hexamethylbiphenyl derivative is a rigid non-planar and highly twisted structure.

[0029] According to an embodiment of the present invention, the hexamethylbiphenyl derivative is selected from one of the following structures:

[0030]

[0031]

[0032]

[0033] According to an embodiment of the present invention, the hexamethylbiphenyl derivative is doped in the host material BCPO film at a concentration of 20%, and basically has a steady-state photoluminescence spectrum as shown in Figure 1 the figure.

[0034] According to an embodiment of the present invention, the hexamethylbiphenyl derivative is doped in the host material BCPO film at a concentration of 20%, and basically has a transient spectrum as shown in Figure 2 the figure.

[0035] According to an embodiment of the present invention, the hexamethylbiphenyl derivative basically has a thermogravimetric analysis (TGA) curve as shown in Figure 3 the figure.

[0036] According to an embodiment of the present invention, the hexamethylbiphenyl derivative basically has a differential scanning calorimetry (DSC) curve as shown in Figure 4 the figure.

[0037] The present invention also provides a preparation method of the above-mentioned hexamethylbiphenyl derivative, which includes the following steps:

[0038] Compound M2 having the structure shown in formula (2) reacts with a compound having X 1 , X 2 , X 3 , X 4 groups to obtain the hexamethylbiphenyl derivative;

[0039]

[0040] In formula (2), X 5 is selected from halogen, preferably iodine element;

[0041] X 1 、X 2 、X 3 、X 4 The definitions of the groups are the same as before.

[0042] According to an embodiment of the present invention, the compound M2 is prepared by a method comprising the following steps: The compound M1 having the structure shown in formula (3) is subjected to a halogenation reaction to obtain the compound M2 having the structure shown in formula (2);

[0043]

[0044] Taking X 5 selected from iodine element as an example, the reaction process is as follows:

[0045]

[0046] According to an embodiment of the present invention, the compound M1 is prepared by a method comprising the following steps:

[0047] In the presence of magnesium powder and iron trichloride, the compound M1 is prepared by the reaction of 2-halomesitylene.

[0048] According to the present invention, the reaction is carried out in a dihaloethane and an organic solvent; for example, the organic solvent is selected from tetrahydrofuran.

[0049] Taking 2-bromomesitylene as an example, the reaction process is as follows:

[0050]

[0051] According to an embodiment of the present invention, the reaction of the compound M2 with the compound having X 1 、X 2 、X 3 、X 4 groups includes:

[0052] First, the compound M3 having the structure shown in formula (4) is synthesized from the compound M2;

[0053]

[0054] In formula (4), X 5 is selected from halogens, preferably iodine element; X 6 is selected from halogens different from X 5 and is preferably bromine element;

[0055] The compound M3 reacts with the compound having X 1 、X 2 、X 3 、X4 React with the compound of the group to obtain the hexamethylbiphenyl derivative.

[0056] Taking X in formula (4) 5 Selected from iodine element, X 6 Taking the compound selected from bromine element as an example, the reaction process of synthesizing compound M3 from compound M2 is shown as follows:

[0057]

[0058] In the above formula, NBS represents N-bromosuccinimide and TFA represents trifluoroacetic acid.

[0059] According to the present invention, the compound having X 1 , X 2 , X 3 or X 4 group has the structures shown in the following formulas (5) to (8):

[0060]

[0061]

[0062] In formulas (5) to (8), X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , Y 4 , the definitions of m1, m2, m3 and m4 are the same as before.

[0063] The present invention also provides a polymer, and the polymer includes at least one repeating unit derived from the above-mentioned hexamethylbiphenyl derivative.

[0064] According to the present invention, the polymer is a homopolymer of the above-mentioned hexamethylbiphenyl derivative.

[0065] According to the present invention, the number-average molecular weight of the polymer is 230 - 2000, preferably, the number-average molecular weight of the polymer is 400 - 1500, and more preferably, the number-average molecular weight of the polymer is 600 - 1200.

[0066] The present invention also provides a use of the above-mentioned hexamethylbiphenyl derivative or its polymer in electronic devices, preferably, in organic electroluminescent devices, organic field effect transistors and organic solar cells.

[0067] The present invention also provides an electronic device, which includes the above-mentioned hexamethylbiphenyl derivative.

[0068] According to an embodiment of the present invention, the electronic device includes two electrodes and an organic layer located between the two electrodes, and the above-mentioned hexamethylbiphenyl derivative is included in the organic layer.

[0069] Preferably, the organic layer is one, two or more of an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

[0070] The present invention provides an organic electroluminescent device, which includes a first electrode and a second electrode arranged opposite to each other, and at least one organic layer is arranged between the first electrode and the second electrode, and the organic layer contains the above-mentioned hexamethylbiphenyl derivative.

[0071] According to an embodiment of the present invention, the organic layer includes one, two or more of an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

[0072] According to an embodiment of the present invention, the hexamethylbiphenyl derivative is located in at least one of the injection layer, the transport layer, the light-emitting layer or the blocking layer.

[0073] Preferably, the injection layer includes a hole injection layer and an electron injection layer; preferably, the transport layer includes a hole transport layer and an electron transport layer; preferably, the blocking layer includes a hole blocking layer and an electron blocking layer.

[0074] According to an embodiment of the present invention, the organic electroluminescent device has an electroluminescence spectrum substantially as Figure 5 shown at different driving voltages.

[0075] According to an embodiment of the present invention, the organic electroluminescent device has an efficiency-luminance curve substantially as Figure 6 shown.

[0076] As an example, the organic electroluminescent device includes an anode, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, and a cathode arranged in sequence from bottom to top.

[0077] As an example, the organic electroluminescent device includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode arranged in sequence from bottom to top.

[0078] As an example, the organic electroluminescent device includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode arranged in sequence from bottom to top.

[0079] Preferably, the anode is disposed on a substrate.

[0080] Preferably, the thickness of the hole injection layer is 0.5 - 15 nm, the thickness of the hole transport layer is 20 - 50 nm, the thickness of the electron blocking layer is 1 - 20 nm, the thickness of the light emitting layer is 20 - 60 nm, the thickness of the hole blocking layer is 5 - 40 nm, the thickness of the electron transport layer is 20 - 60 nm, and the thickness of the electron injection layer is 0.5 - 1.5 nm.

[0081] More preferably, the thickness of the hole injection layer is 1 - 10 nm, the thickness of the hole transport layer is 30 - 40 nm, the thickness of the electron blocking layer is 5 - 15 nm, the thickness of the light emitting layer is 25 - 35 nm, the thickness of the hole blocking layer is 10 - 20 nm, the thickness of the electron transport layer is 30 - 50 nm, and the thickness of the electron injection layer is 0.8 - 1 nm.

[0082] As an example, the thickness of the hole injection layer is 1 nm, the thickness of the hole transport layer is 30 nm, the thickness of the electron blocking layer is 10 nm, the thickness of the light emitting layer is 30 nm, the thickness of the hole blocking layer is 10 nm, the thickness of the electron transport layer is 30 nm, and the thickness of the electron injection layer is 1 nm.

[0083] As an example, the thickness of the hole injection layer is 10 nm, the thickness of the hole transport layer is 30 nm, the thickness of the electron blocking layer is 10 nm, the thickness of the light emitting layer is 30 nm, the thickness of the electron transport layer is 40 nm, and the thickness of the electron injection layer is 1 nm.

[0084] According to the embodiments of the present invention, the anode is made of a conductive metal, a metal oxide, or a conductive polymer. Preferably, the conductive metal includes gold, silver, copper, platinum, aluminum. Preferably, the metal oxide includes indium zinc oxide, nickel oxide, indium oxide, zinc oxide, or indium tin oxide. Preferably, the conductive polymer includes polyacetylene, polypyrrole, polyindole, polyaniline, phthalocyanine chelate, poly(p - phenylene vinylene), poly(3 - alkylthiophene). For example, it is indium tin oxide (ITO).

[0085] Preferably, the anode is prepared by a deposition method, and the deposition method includes radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam. More preferably, the anode is pattern - structured.

[0086] According to the embodiments of the present invention, the cathode is made of a conductive metal or a metal oxide. In principle, all materials that can be used as the cathode of an OLED can potentially be used as the cathode material of the device of the present invention.

[0087] Preferably, the cathode material includes Al, Au, Ag, Ca, Ba, Mg, LiF / Al, Mg / Ag alloy, BaF 2 / Al, Cu, Fe, Co, Ni, Mn, Pd, or ITO.

[0088] Preferably, the cathode is prepared by a deposition method, and the deposition method includes radio frequency magnetron sputtering, vacuum thermal evaporation, and electron beam.

[0089] Preferably, the substrate includes plastic, metal, semiconductor wafer or glass, such as a glass substrate.

[0090] According to an embodiment of the present invention, the material of the hole injection layer includes porphyrin compounds, triphenylamine compounds and / or coating-type polymer materials, such as copper phthalocyanine; preferably, the hole injection layer is a film structure, and the film structure is a single-layer film or a multi-layer film.

[0091] According to an embodiment of the present invention, the material of the hole transport layer includes compounds containing carbazolylphenyl and arylamine compounds, such as 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine (NPB), tris(4-carbazol-9-ylphenyl)amine (TCTA), the above-mentioned hexamethylbiphenyl derivatives. Preferably, the hole transport layer is a film structure, and more preferably, it is a single-component film structure or a multi-component film structure containing the above-mentioned hexamethylbiphenyl derivatives, and the film structure is a single-layer film structure or a multi-layer film structure.

[0092] According to an embodiment of the present invention, the material of the electron blocking layer includes compounds containing carbazolylphenyl and arylamine compounds, such as 3,3'-bis(9H-carbazol-9-yl)-1,1'-biphenyl (mCBP), 1,3-bis(carbazol-9-yl)benzene (mCP), 2,6-bis(9-carbazolyl)pyridine (mCPy), hexamethylbiphenyl derivatives. Preferably, the electron blocking layer is a film structure, and more preferably, it is a single-component film structure or a multi-component film structure containing the above-mentioned hexamethylbiphenyl derivatives, and the film structure is a single-layer film structure or a multi-layer film structure.

[0093] According to an embodiment of the present invention, the light-emitting layer includes a light-emitting material. Preferably, the light-emitting layer further includes a host material; preferably, the light-emitting material includes a fluorescent material, a phosphorescent material and a thermally activated delayed fluorescence material, such as the above-mentioned hexamethylbiphenyl derivatives; the host material includes a material with the lowest triplet energy level T 1 > 2.2 eV material, preferably T 1 > 2.5 eV material, such as the above-mentioned hexamethylbiphenyl derivatives.

[0094] According to the present invention, the light-emitting layer is a film structure.

[0095] According to an embodiment of the present invention, the material of the hole blocking layer includes a material having a lower highest occupied molecular orbital energy level and a higher lowest triplet energy level compared to the light-emitting material, such as the above-mentioned hexamethylbiphenyl derivative, the compound containing a phosphine oxide group, or the triazine derivative.

[0096] According to an embodiment of the present invention, the material of the electron transport layer is a compound having electron transport properties, such as the above-mentioned hexamethylbiphenyl derivative, the azole derivative, the triazine derivative, the pyridine derivative, or the metal complex.

[0097] Preferably, the hole blocking layer and the electron transport layer are in a film structure, preferably, an independent film structure or a mixed film structure formed by mixing the hole blocking layer material and the electron transport layer material, and the film structure is a single-layer film structure or a multi-layer film structure.

[0098] According to an embodiment of the present invention, the material of the electron injection layer includes alkali metal salts such as lithium fluoride and cesium fluoride; magnesium fluoride and tris(8-hydroxyquinoline) aluminum, and the electron injection layer is in a film structure, and the film structure is a single-layer film structure or a multi-layer film structure.

[0099] Preferably, the film structure is obtained by evaporating, spin-coating, or inkjet-printing the above materials.

[0100] The present invention also provides a method for manufacturing the above-mentioned organic electroluminescent device, including the following steps: sequentially disposing an anode, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, and a cathode on a substrate.

[0101] Preferably, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially disposed on the substrate.

[0102] Preferably, the organic electroluminescent device includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, which are sequentially disposed on the substrate from bottom to top.

[0103] Preferably, the anode, the hole injection layer, the hole transport layer, the electron blocking layer, the light-emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode are disposed by evaporation, spin-coating, or inkjet-printing, for example, by evaporation.

[0104] More preferably, the evaporation is carried out under a vacuum condition, for example, under a condition where the vacuum degree is lower than 2×10 -5 Pa, and further preferably, the evaporation rate is 0.2 nm / s.

[0105] Mechanism description: By introducing the six-methylbiphenyl structural unit with a three-dimensional structure, the six-methylbiphenyl derivative of the present invention can effectively inhibit the crystallization tendency of molecules, improve the thermal stability and film-forming properties of the material, thereby enhancing the efficiency and lifespan of the material and the device; by introducing a highly twisted six-methylbiphenyl structural unit, the planar interaction between molecules can be effectively inhibited, thereby reducing exciton annihilation and improving the energy utilization rate, thus improving the efficiency and lifespan of related materials and devices.

[0106] Meanwhile, due to the special structural rigidity of six-methylbiphenyl in the six-methylbiphenyl derivative, the non-radiative relaxation caused by the vibration and rotation of molecules can be effectively inhibited, thus having high luminescence efficiency and carrier transport performance.

[0107] Beneficial effects

[0108] (1) By introducing the rigid non-planar six-methylbiphenyl structural unit into the molecule, the present invention can inhibit the ordered arrangement and crystallization of molecules, effectively improve the thermal stability and film-forming quality of the material, and at the same time inhibit the aggregation quenching effect between molecules, so that the six-methylbiphenyl derivative of the present invention has good thermal stability, film-forming properties and high luminescence efficiency, and can be used to prepare electronic devices such as organic light-emitting diodes, organic solar cells and organic field-effect transistors. Especially as a constituent material for the light-emitting layer, hole injection layer, hole transport layer, hole blocking layer, electron blocking layer or electron transport layer in organic light-emitting diodes, the device can exhibit advantages such as good stability, high luminescence efficiency, low driving voltage and high brightness, which are significantly superior to existing organic light-emitting diodes.

[0109] (2) The preparation method of the six-methylbiphenyl derivative of the present invention is simple, and the raw materials are easily available, which can meet the development needs of industrialization.

[0110] (3) The six-methylbiphenyl derivative of the present invention has good application effects in electronic devices such as organic light-emitting diodes, organic solar cells and organic field-effect transistors, and has broad industrialization prospects. Brief description of the drawings

[0111] Figure 1 It is the steady-state photoluminescence spectrum of the compounds (compounds 1-34 and 1-36) of Example 6 and Example 7 of the present invention doped in the host material bis[4-(9'-carbazolyl)phenyl]phenylphosphine oxide (BCPO) film at a concentration of 20%.

[0112] Figure 2 It is the transient spectrum of the compound (compound 1-34) of Example 6 of the present invention doped in the host material BCPO film at a concentration of 20%.

[0113] Figure 3TG (Thermogravimetric analysis) curves of the compounds (Compound 1-34 and 1-36) in Example 6 and Example 7 of the present invention. The thermal decomposition temperatures of Compound 1-34 and 1-36 are 434 °C and 480 °C respectively, indicating their excellent thermal stability.

[0114] Figure 4 DSC (Differential Scanning Calorimetry) curves of the compounds (Compound 1-34 and 1-36) in Example 6 and Example 7 of the present invention. The thermal decomposition temperatures of Compound 1-34 and 1-36 are 177 °C and 183 °C respectively, indicating their excellent film-forming stability.

[0115] Figure 5 Electroluminescence spectra of the organic light-emitting devices (OLED-6 and OLED-7) in Example 14 and Example 15 of the present invention at different driving voltages. It shows that the devices have excellent luminescent color stability.

[0116] Figure 6 Efficiency-luminance curves of the organic light-emitting devices (OLED-6 and OLED-7) in Example 14 and Example 15 of the present invention. It shows that the devices have high luminous efficiency.

[0117] Figure 7 It is a diagram showing the structure of the organic light-emitting devices in Example 9 to Example 16 of the present invention.

[0118] Wherein, 1 - substrate, 2 - anode, 3 - hole injection layer, 4 - hole transport layer, 5 - electron blocking layer, 6 - light-emitting layer, 7 - hole blocking layer, 8 - electron transport layer, 9 - electron injection layer, 10 - cathode. Detailed Description of the Invention

[0119] The general formula compounds of the present invention, their preparation methods and applications will be further described in detail below with reference to specific examples. It should be understood that the following examples are only for illustrative purposes to explain the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection of the present invention.

[0120] Term Definitions and Explanations

[0121] Unless otherwise specified, the definitions of groups and terms recorded in the specification and claims of this application, including their definitions as examples, exemplary definitions, preferred definitions, definitions recorded in tables, definitions of specific compounds in examples, etc., can be combined and combined with each other arbitrarily. The group definitions and compound structures after such combination and combination should fall within the scope of protection of this application.

[0122] For the numerical ranges recited in the description and claims of the present application, when the numerical range can only be "integers", it should be understood that the two endpoints of the range and each integer within the range are recited. For example, "1-10" for the number of carbon atoms should be understood to recite each of the integers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0123] "Halogen" as used in the present invention refers to fluorine, chlorine, bromine, and iodine.

[0124] "Alkyl", when used alone or as a suffix or prefix in the present invention, is intended to include branched and straight-chain saturated aliphatic hydrocarbon groups having 1 to 20, preferably 1-6 carbon atoms (or if a specific number of carbon atoms is provided, refers to that specific number). For example, "C1-6 alkyl" represents straight-chain and branched alkyl groups having 1, 2, 3, 4, 5, or 6 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl.

[0125] The term "cycloalkyl" as used in the present invention is intended to include saturated cyclic groups having a specified number of carbon atoms. These terms may include fused or bridged polycyclic systems. Cycloalkyl has 3 to 40 carbon atoms in its ring structure. In one embodiment, cycloalkyl has 3-10 carbon atoms in its ring structure. For example, "C3-6 cycloalkyl" represents groups such as cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl.

[0126] The term "aryl" as used in the present invention refers to an aromatic ring structure composed of 5 to 20 carbon atoms. For example: an aromatic ring structure containing 5, 6, 7, and 8 carbon atoms can be a monocyclic aromatic group such as phenyl; a ring structure containing 8, 9, 10, 11, 12, 13, or 14 carbon atoms can be polycyclic such as naphthyl. The aromatic ring may be substituted at one or more ring positions with the above-mentioned substituents. The term "aryl" also includes polycyclic ring systems having two or more rings, where two or more carbons are common to two adjacent rings (the rings are "fused rings"), where at least one ring is aromatic and the other rings can be, for example, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, and / or heterocyclic groups. Examples of polycycles include, but are not limited to, 2,3-dihydro-1,4-benzodioxin and 2,3-dihydro-1-benzofuran.

[0127] As used herein, "heteroaryl" refers to a heteroaromatic heterocycle having at least one ring heteroatom (such as sulfur, oxygen or nitrogen). Heteroaryl includes monocyclic systems and polycyclic systems (such as those having 2, 3 or 4 fused rings). Examples of heteroaryl include, but are not limited to, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furyl, quinolinyl, isoquinolinyl, thienyl, imidazolyl, thiazolyl, indolyl, pyrrolyl, oxazolyl, benzofuranyl, benzothienyl, benzothiazolyl, isoxazolyl, pyrazolyl, triazolyl, tetrazolyl, indazolyl, 1,2,4-thiadiazolyl, isothiazolyl, benzothienyl, purinyl, carbazolyl, benzimidazolyl, benzoxazolyl, azabenzoxazolyl, imidazothiazolyl, benzo[1,4]dioxanyl, benzo[1,3]dioxolyl, etc. In some embodiments, heteroaryl has 3 to 40 carbon atoms and in other embodiments has 3 to 20 carbon atoms. In some embodiments, heteroaryl contains 3 to 14, 4 to 14, 3 to 7 or 5 to 6 ring-forming atoms. In some embodiments, heteroaryl has 1 to 4, 1 to 3 or 1 to 2 heteroatoms. In some embodiments, heteroaryl has 1 heteroatom.

[0128] Unless otherwise specified, the term "heterocyclic group" as used herein refers to a saturated, unsaturated or partially saturated monocyclic, bicyclic or tricyclic ring containing 3 to 20 atoms, wherein 1, 2, 3, 4 or 5 ring atoms are selected from nitrogen, sulfur or oxygen, which may be linked through carbon or nitrogen, wherein the -CH2- group is optionally replaced by -C(O)-; and wherein unless otherwise stated to the contrary, the ring nitrogen atom or ring sulfur atom is optionally oxidized to form an N-oxide or S-oxide or the ring nitrogen atom is optionally quaternized; wherein the -NH in the ring is optionally substituted by acetyl, formyl, methyl or methanesulfonyl; and the ring is optionally substituted by one or more halogens. It should be understood that when the total number of S and O atoms in the heterocyclic group exceeds 1, these heteroatoms are not adjacent to each other. If the heterocyclic group is bicyclic or tricyclic, at least one ring may optionally be a heteroaromatic ring or an aromatic ring, provided that at least one ring is non-heteroaromatic. If the heterocyclic group is monocyclic, it must not be aromatic. Examples of heterocyclic groups include, but are not limited to, piperidinyl, N-acetylpiperidinyl, N-methylpiperidinyl, N-formylpiperazinyl, N-methanesulfonylpiperazinyl, homopiperazinyl, piperazinyl, azetidinyl, oxetanyl, morpholinyl, tetrahydroisoquinolinyl, tetrahydroquinolinyl, dihydroindolyl, tetrahydropyranyl, dihydro-2H-pyranyl, tetrahydrofuryl, tetrahydrothiopyranyl, tetrahydrothiopyran-1-oxide, tetrahydrothiopyran-1,1-dioxide, 1H-pyridin-2-one and 2,5-dioxoimidazolidinyl.

[0129] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0130] Example 1

[0131] Synthesis of Compound 1-1

[0132] [Synthesis of Compound M1]

[0133] The synthesis route of Compound M1 is as follows:

[0134]

[0135] Under a nitrogen atmosphere, magnesium powder (2.55 g, 105 mmol) and dry tetrahydrofuran (120 mL) were added to a dry reaction flask and heated to reflux. 2-Bromomesitylene (19.9 g, 100 mmol) was added dropwise to the system, and the reaction system was refluxed and stirred for 8 hours. Thereafter, a mixed solution of 1,2-dibromoethane (6.5 mL, 75 mmol) and tetrahydrofuran (20 mL) dissolved with iron(III) chloride (1.62 g, 10 mmol) was added dropwise to the above reaction system and refluxed and stirred for another 5 hours. After cooling to room temperature, the reaction solution was quenched with dilute hydrochloric acid (2%, 50 mL) and extracted with ethyl acetate. The organic phase was washed with saturated brine and then dried over Na 2 SO 4 dried, the solvent was evaporated, and purified by column chromatography (mobile phase: petroleum ether) to obtain a transparent block solid (8.2 g, yield: 69%).

[0136] MS(EI): m / z 238.17 [M + ; Combustion elemental analysis: C 18 H 22 (%) Calculated value: C 90.70; H 9.30; Found value: C 90.67, H 9.33.

[0137] [Synthesis of Compound M2]

[0138] The synthesis route of Compound M2 is as follows:

[0139]

[0140] Compound M1 (2.38 g, 10 mmol) was dissolved in dry acetonitrile (50 mL) and cooled to 0 °C. N-Iodosuccinimide (4.95 g, 22 mmol) and trifluoroacetic acid (0.5 mL) were added thereto in sequence at this temperature, and the mixture was stirred overnight at room temperature. After evaporation of the solvent, dichloromethane, aqueous sodium bicarbonate solution and saturated brine were added, and after multiple extractions, the organic phase was dried, evaporated and purified by column chromatography (mobile phase: petroleum ether) to obtain a white solid (4.5 g, yield: 92%).

[0141] MS(EI): m / z 489.96 [M +; Combustion elemental analysis: C 18 H 20 I 2 (%) Calculated values: C 44.11; H 4.11; Measured values: C 44.10, H 4.13.

[0142] [Synthesis of Compound 1-1]

[0143] The synthesis route of Compound 1-1 is as follows:

[0144]

[0145] Under a nitrogen atmosphere, carbazole (2.0 g, 12 mmol), M2 (2.45 g, 5 mmol), anhydrous potassium carbonate (4.15 g, 30 mmol), copper(I) iodide (0.38 g, 2 mmol), 1,10-phenanthroline (0.40 g, 2 mmol) and DMA (15 mL) were added to a reaction flask, heated to 180 °C and refluxed with stirring for 36 hours. After cooling to room temperature, 100 mL of water was added to the reaction solution, and it was extracted with ethyl acetate. The organic phase was washed several times with saturated brine, and then dried over Na 2 SO 4 dried, the solvent was evaporated, and it was purified by column chromatography (mobile phase: petroleum ether) to obtain a white solid (0.8 g, yield: 28%).

[0146] MS (EI): m / z 568.28 [M + ; Combustion elemental analysis: C 42 H 36 N 2 (%) Calculated values: C, 88.69; H, 6.38; N, 4.93 Measured values: C, 88.60; H, 6.41; N, 4.99.

[0147] Example 2

[0148] Synthesis of Compound 1-3

[0149] [Synthesis of Compound M3]

[0150] The synthesis route of Compound M3 is as follows:

[0151]

[0152] Compound M2 (4.90 g, 10 mmol) was dissolved in dry acetonitrile (50 mL) and cooled to 0 °C. At this temperature, N-bromosuccinimide (3.92 g, 22 mmol) and trifluoroacetic acid (0.5 mL) were successively added thereto. The mixture was stirred overnight at room temperature. After evaporation of the solvent, dichloromethane, aqueous sodium bicarbonate solution and saturated brine were added. After extraction for several times, the organic phase was dried, evaporated and purified by column chromatography (mobile phase: petroleum ether) to obtain a white solid (5.8 g, yield: 90%).

[0153] MS (EI): m / z 647.78 [M + ; Elemental analysis by combustion method: C 18 H 18 Br 2 I 2 (%) Calculated: C 33.37; H 2.80; Found: C 33.41, H 2.76.

[0154] [Synthesis of Compound M4]

[0155] The synthetic route of compound M4 is as follows:

[0156]

[0157] Under a nitrogen atmosphere, carbazole (2.0 g, 12 mmol), M3 (3.24 g, 5 mmol), anhydrous potassium carbonate (4.15 g, 30 mmol), copper(I) iodide (0.38 g, 2 mmol), 1,10-phenanthroline (0.40 g, 2 mmol) and DMA (15 mL) were added to a reaction flask. The mixture was heated to 180 °C and refluxed with stirring for 36 hours. After cooling to room temperature, 100 mL of water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic phase was washed several times with saturated brine, dried over Na 2 SO 4 and evaporated to dryness. Purification by column chromatography gave a white solid (1.2 g, yield: 33%).

[0158] MS (EI): m / z 726.55 [M + ; Elemental analysis by combustion method: C 42 H 34 Br 2 N 2 (%) Calculated: C, 69.43; H, 4.72; N, 3.86 Found: C, 69.52; H, 4.73; N, 3.80.

[0159] [Synthesis of Compound 1-3]

[0160] The synthetic route of compound 1-3 is as follows:

[0161]

[0162] After dissolving compound M4 (0.73 g, 1 mmol) in DMF (8 mL), cuprous cyanide (0.27 g, 3 mmol) was added thereto. The mixture was heated to 140 °C and stirred for 24 hours. After the reaction solution was cooled to room temperature, ammonia water (25%, 15 mL) was added thereto. The mixture was extracted with dichloromethane several times, and the organic phase was dried and concentrated by evaporation. The product was purified by column chromatography to obtain a white solid (0.42 g, yield: 68%).

[0163] MS (EI): m / z 618.27 [M + ; Combustion elemental analysis: C 44 H 34 N 4 (%) Calculated value: C, 85.41; H, 5.54; N, 9.05 Found value: C, 85.43; H, 5.51; N, 9.06.

[0164] Example 3

[0165] Synthesis of Compounds 1-6

[0166] [Synthesis of Compounds 1-6]

[0167] The synthetic route of Compounds 1-6 is as follows:

[0168]

[0169] Under a nitrogen atmosphere, compound M4 (0.73 g, 1 mmol), diphenyltriazine borate (pinacol) ester (0.72 g, 2 mmol), tetrakis(triphenylphosphine)palladium (0.058 g, 0.05 mmol), potassium carbonate (0.69 g, 5 mmol), 1,4-dioxane (4 mL) and water (2 mL) were added to a reaction flask. After the mixture was refluxed and stirred for 24 hours, 30 mL of water was added thereto. The mixture was extracted with dichloromethane several times, and the organic phase was dried and concentrated by evaporation. The product was purified by column chromatography to obtain a white solid (0.59 g, yield: 57%).

[0170] MS (EI): m / z 1030.44 [M + ; Combustion elemental analysis: C 72 H 54 N 8 (%) Calculated value: C, 83.86; H, 5.28; N, 10.87 Found value: C, 83.82; H, 5.29; N, 10.89.

[0171] Example 4

[0172] Synthesis of Compounds 1-10

[0173] [Synthesis of Compounds 1 - 10]

[0174] The synthetic routes of Compounds 1 - 10 are as follows:

[0175]

[0176] Under a nitrogen atmosphere, Compound M4 (0.73 g, 1 mmol) was dissolved in 5 mL of dry cyclopentyl methyl ether. n-BuLi hexane solution (2.5 M, 1 mL, 2.5 mmol) was added dropwise thereto at 0 °C, and the mixture was stirred at this temperature for an additional 30 minutes. Then, a solution of bis(trimethylphenyl)boron fluoride (0.59 g, 2.2 mmol) in cyclopentyl methyl ether (3 mL) was added dropwise. After the addition was complete, the mixture was warmed to room temperature and stirred overnight. After the reaction was completed, saturated aqueous ammonium chloride solution was added to the reaction mixture, and the mixture was extracted with dichloromethane. The obtained organic phase was washed with saturated brine and dried over anhydrous sodium sulfate. After evaporation, the crude product was purified by column chromatography to obtain a pale yellow solid (0.55 g, yield: 52%).

[0177] MS(EI): m / z 1064.64 [M + ; Combustion elemental analysis: C 78 H 78 N 2 B 2 (%) Calculated: C, 87.96; H, 7.38; N, 2.63 Found: C, 87.94; H, 7.35; N, 2.70.

[0178] Example 5

[0179] Synthesis of Compound 1 - 20

[0180] [Synthesis of Compound M5]

[0181] The synthetic route of Compound M5 is as follows:

[0182]

[0183] In a 150 mL high-pressure tube, M2 (1.96 g, 4 mmol), 4-bromo-3-fluorophenylboronic acid (2.62 g, 12 mmol), Pd(PPh 3 ) 4 (0.277 g, 0.24 mmol), toluene (20 mL), THF (10 mL), and 2 M K 2 CO 3Aqueous solution (10 mL). After purging with nitrogen multiple times, the tube was stoppered tightly. The mixture was heated and stirred at 90 °C for 24 hours. After the reaction solution was cooled to room temperature, it was extracted with ethyl acetate multiple times. After washing with saturated brine, the organic phase was dried over anhydrous sodium sulfate, concentrated by rotary evaporation, and the crude product was purified by column chromatography to obtain a white solid (2.0 g, yield: 86%). MS (EI): m / z 584.03 [M + ; Combustion elemental analysis: C 30 H 26 Br 2 F 2 (%) Calculated: C, 61.66; H, 4.49 Found: C, 61.63; H, 4.51.

[0184] [Synthesis of Compound M6]

[0185] The synthetic route of compound M6 is as follows:

[0186]

[0187] Under a nitrogen atmosphere, M5 (1.17 g, 2 mmol), carbazole (0.67 g, 4 mmol) and cesium carbonate (2.6 g, 8 mmol) were added to 10 mL of dimethylformamide (DMF). The mixture was stirred at 150 °C for 12 hours and then poured into 400 mL of water. The precipitate was collected by filtration. Purification by column chromatography gave a white solid (1.45 g, yield: 80%). MS (EI): m / z 910.23 [M + ; Combustion elemental analysis: C 56 H 50 Br 2 N 2 (%) Calculated: C, 73.85; H, 5.53; N, 3.08 Found: C, 73.89; H, 5.50; N, 3.02.

[0188] [Synthesis of Compound 1-20]

[0189] The synthetic route of compound 1-20 is as follows:

[0190]

[0191] Under a nitrogen atmosphere, compound M6 (0.91 g, 1 mmol) was dissolved in 5 mL of dry cyclopentyl methyl ether. n-BuLi hexane solution (2.5 M, 1 mL, 2.5 mmol) was added dropwise thereto at 0 °C, and the mixture was stirred at this temperature for 30 minutes. Then, a cyclopentyl methyl ether solution (3 mL) of bis(trimethylphenyl) boron fluoride (0.59 g, 2.2 mmol) was added dropwise thereto. After the addition was completed, the mixture was warmed to room temperature and stirred overnight. After the reaction was completed, saturated aqueous ammonium chloride solution was added to the reaction mixture, and the mixture was extracted with dichloromethane. The obtained organic phase was washed with saturated brine and dried over anhydrous sodium sulfate. After evaporation, the crude product was purified by column chromatography to obtain a pale yellow solid (0.64 g, yield: 61%). MS (EI): m / z 1048.76 [M + ; Combustion elemental analysis: C 92 H 94 N 2 B 2 (%) Calculated: C, 88.44; H, 7.58; N, 2.24 Found: C, 88.46; H, 7.55; N, 2.26.

[0192] Example 6

[0193] Synthesis of Compound 1-34

[0194] [Synthesis of Compound M7]

[0195] The synthetic route of compound M7 is as follows:

[0196]

[0197] M2 (1.96 g, 4 mmol), phenylboronic acid (1.47 g, 12 mmol), Pd(PPh 3 ) 4 (0.277 g, 0.24 mmol), toluene (20 mL), THF (10 mL), and 2 M aqueous K 2 CO 3 solution (10 mL) were added to a 150 mL high-pressure tube. After purging with nitrogen several times, the tube was stoppered, and the mixture was heated and stirred at 90 °C for 24 hours. After the reaction solution was cooled to room temperature, it was extracted with ethyl acetate several times. After washing with saturated brine, the organic phase was dried over anhydrous sodium sulfate. After evaporation, the crude product was purified by column chromatography to obtain a white solid (1.48 g, yield: 95%). MS (EI): m / z 390.23 [M + ; Combustion elemental analysis: C 30 H 30 (%) Calculated: C, 92.26; H, 7.74 Found: C, 92.27; H, 7.73.

[0198] [Synthesis of Compound M8]

[0199] The synthetic route of compound M8 is as follows:

[0200]

[0201] Anhydrous AlCl 3 (0.96 g, 7.2 mmol), compound M7 (1.18 g, 3 mmol) and 40 mL CS 2 After adding to the reaction flask and cooling to 0°C, p-bromobenzoyl chloride (1.45 g, 6.6 mmol) was added dropwise thereto. Subsequently, the reaction mixture was heated and stirred at 50°C for 12 hours. After the reaction was completed, crushed ice was added to the reaction mixture, and it was extracted several times with dichloromethane. The obtained organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and spin-dried. The crude product was purified by column chromatography to obtain a white solid (1.8 g, yield: 79%).

[0202] MS(EI): m / z 756.10[M + ]; Combustion method element analysis: C 44 H 36 Br 2 O 2 (%) Calculated value: C, 69.85; H, 4.80 Found: C, 69.80; H, 4.87.

[0203]

[0204] In a nitrogen atmosphere, compound M8 (0.757, 1mmol), 9,9-dimethylacridine (0.314g, 1.5mmol), tri-tert-butylphosphine tetrafluoroborate (0.029g, 0.1mmol), sodium tert-butoxide (0.29g, 3mmol), palladium acetate (0.022g, 0.1mmol) and dry toluene were added to a reaction flask, and the mixture was stirred at 90°C for 18 hours and then cooled to room temperature. After the solvent was dried, dichloromethane was added for extraction, and after washing with saturated brine for several times, it was dried over anhydrous sodium sulfate. After drying, the crude product was purified by column chromatography to obtain a light yellow solid (0.9g, yield: 89%).

[0205] MS (EI): m / z 1035.48 [M+Na]; Combustion method elemental analysis: C 74 H 64 N 2 O 2 (%) Calculated value: C, 87.71; H, 6.37; N, 2.76 Found value: C, 87.71; H, 6.15; N, 2.85.

[0206] Example 7

[0207] Synthesis of Compound 1-36

[0208] The synthetic route of compound 1-36 is as follows:

[0209]

[0210] In a nitrogen atmosphere, compound M8 (0.757, 1mmol), phenoxazine (0.275g, 1.5mmol), tri-tert-butylphosphine tetrafluoroborate (0.029g, 0.1mmol), sodium tert-butoxide (0.29g, 3mmol), palladium acetate (0.022g, 0.1mmol) and dry toluene were added to a reaction flask, and the mixture was stirred at 90°C for 18 hours and then cooled to room temperature. After the solvent was dried, dichloromethane was added for extraction, and after washing with saturated brine for several times, it was dried with anhydrous sodium sulfate. After drying, the crude product was purified by column chromatography to obtain a light yellow solid (0.9g, yield: 92%). MS (EI): m / z 983.38 [M+Na]; Combustion method elemental analysis: C 68 H 52 N 2 O 4 (%) Calculated value: C, 84.97; H, 5.45; N, 2.91 Found value: C, 84.97; H, 5.41; N, 3.02.

[0211] Example 8

[0212] Synthesis of Compound 1-37

[0213] [Synthesis of Compound M9]

[0214] The synthetic route of compound M9 is as follows:

[0215]

[0216] Anhydrous AlCl 3 (0.96 g, 7.2 mmol), compound M7 (1.18 g, 3 mmol) and 40 mL CS 2 After adding to the reaction flask and cooling to 0°C, p-bromobenzenesulfonyl chloride (1.69 g, 6.6 mmol) was added dropwise thereto. Subsequently, the reaction mixture was heated and stirred at 50°C for 12 hours. After the reaction was completed, crushed ice was added to the reaction mixture, and it was extracted several times with dichloromethane. The obtained organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, and dried by spin drying. The crude product was purified by column chromatography to obtain a white solid (1.7 g, yield: 69%). MS (EI): m / z 828.04 [M + ]; Combustion method element analysis: C 42 H 36 Br2 O 4 S 2 (%) Calculated value: C, 60.88; H, 4.38 Found value: C, 60.93; H, 4.34.

[0217] [Synthesis of Compound 1-37]

[0218] The synthetic route of compound 1-37 is as follows:

[0219]

[0220] In a nitrogen atmosphere, compound M9 (0.83, 1mmol), phenoxazine (0.275g, 1.5mmol), tri-tert-butylphosphine tetrafluoroborate (0.029g, 0.1mmol), sodium tert-butoxide (0.29g, 3mmol), palladium acetate (0.022g, 0.1mmol) and dry toluene were added to a reaction flask, and the mixture was stirred at 90°C for 18 hours and then cooled to room temperature. After the solvent was dried, dichloromethane was added for extraction, and after washing with saturated brine for several times, it was dried over anhydrous sodium sulfate. After drying, the crude product was purified by column chromatography to obtain a light yellow solid (0.84g, yield: 79%).

[0221] MS (EI): m / z 1064.39 [M+]; Combustion elemental analysis: C 68 H 60 N 2 O 6 S 2 (%) Calculated value: C, 76.66; H, 5.68; N, 2.63 Found: C, 76.66; H, 5.59; N, 2.69.

[0222] Example 9

[0223] Preparation of organic electroluminescent device 1 (OLED-1)

[0224] In this embodiment, the compound 1-1 described in Example 1 is used as the main material, the commercial iridium complex Flrpic is used as the doped luminescent material, indium tin oxide (ITO) is used as the anode, HATCN is used as the hole injection material, α-NPD is used as the hole transport material, mCP is used as the electron blocking material, TPBi is used as the electron transport material, LiF is used as the electron injection material, and metal aluminum (Al) is used as the cathode material to construct an electroluminescent device having a device structure of ITO / HATCN / α-NPD / mCP / compound 1-1:Flrpic (10%) / TPBi / LiF / Al.

[0225] Specifically, a glass substrate with an ITO transparent conductive layer is cleaned with an alkaline solution and rinsed thoroughly with deionized water, then ultrasonically treated in deionized water, acetone, and isopropyl alcohol for ten minutes each. After baking in a clean environment until there is no solvent residue, it is treated with ultraviolet ozone for 15 minutes. The treated substrate is placed in a vacuum chamber and evacuated to a pressure below 2×10-5 Pa. On this substrate, HATCN is evaporated at a deposition rate of 0.2 nm / s to form a layer with a thickness of 10 nm as the hole injection layer (HIL). On the hole injection layer, α-NPD is evaporated at a deposition rate of 0.2 nm / s to form a layer with a thickness of 30 nm as the hole transport layer (HTL). On the hole transport layer, mCP is evaporated at a deposition rate of 0.2 nm / s to form a layer with a thickness of 10 nm as the electron blocking layer (EBL). On the electron blocking layer, dual-source co-evaporation is carried out at a deposition rate of 0.2 nm / s for compound 1-1 as the host material and 0.2 nm / s for the doped luminescent material Flrpic to form a layer with a thickness of 30 nm as the light-emitting layer, and the doping mass ratio of the doped material is 6 wt%. On the light-emitting layer, TPBi is evaporated at a deposition rate of 0.2 nm / s to form a layer with a thickness of 40 nm as the electron transport layer (ETL). On the electron transport layer, LiF is evaporated at a deposition rate of 0.02 nm / s to form a layer with a thickness of 1 nm as the electron injection layer (EIL). Finally, on the electron injection layer, Al is evaporated at a deposition rate of 0.5 nm / s to form a cathode with a thickness of 100 nm.

[0226] Example 10

[0227] Preparation of Organic Electroluminescent Device 2 (OLED-2)

[0228] Except for using compound 1-3 described in Example 2 as the host material instead of compound 1-1 described in Example 1, OLED-2 is prepared under the same production conditions as OLED-1.

[0229] Comparative Example I and Comparative Example II: Preparation of OLED-I and OLED-II

[0230] Except for using commercial host materials compound CBP and compound mCBP as the host material instead of compound 1-1 described in Example 1, comparative OLED-I and comparative OLED-II are prepared under the same production conditions as OLED-1.

[0231] Example 11

[0232] Preparation of Organic Electroluminescent Device 3 (OLED-3)

[0233] In this embodiment, compound 1-6 described in Example 3 is used as the doped luminescent material, commercial compound BCPO as the host material, indium tin oxide (ITO) as the anode, molybdenum trioxide (MoO3) as the hole injection material, TAPC as the hole transport material, mCP as the electron blocking material, DPEPO as the hole blocking material, TmPyPB as the electron transport material, LiF as the electron injection material, and metallic aluminum (Al) as the cathode material to construct an electroluminescent device with a device structure of ITO / MoO3 / TAPC / mCP / BCPO: compound 1-6 (20 wt%) / DPEPO / TmPyPB / LiF / Al.

[0234] Specifically, the glass substrate with an ITO transparent conductive layer is cleaned with an alkaline solution and rinsed thoroughly with deionized water, then ultrasonically treated in deionized water, acetone, and isopropyl alcohol for ten minutes each, baked in a clean environment until there is no solvent residue, and then treated with ultraviolet ozone for 15 minutes. The treated substrate is placed in a vacuum chamber and evacuated to a pressure lower than 2×10 -5 Pa. On this substrate, MoO 3 is evaporated at an evaporation rate of 0.02 nm / s to form a layer with a film thickness of 1 nm as the hole injection layer (HIL).

[0235] On the hole injection layer, TAPC is evaporated at an evaporation rate of 0.2 nm / s to form a layer with a film thickness of 30 nm as the hole transport layer (HTL). On the hole transport layer, mCP is evaporated at an evaporation rate of 0.2 nm / s to form a layer with a film thickness of 10 nm as the electron blocking layer (EBL).

[0236] On the electron blocking layer, co-evaporation of the host material compound BCPO at an evaporation rate of 0.2 nm / s and the doped luminescent material compound 1-6 at an evaporation rate of 0.2 nm / s is carried out to form a layer with a film thickness of 30 nm as the light-emitting layer, and the doping mass ratio of the doping material is 20 wt%.

[0237] On the light-emitting layer, DPEPO is evaporated at an evaporation rate of 0.2 nm / s to form a layer with a film thickness of 10 nm as the hole blocking layer (ETL). On the hole blocking layer, TmPyPB is evaporated at an evaporation rate of 0.2 nm / s to form a layer with a film thickness of 30 nm as the electron transport layer (ETL). On the electron transport layer, LiF is evaporated at an evaporation rate of 0.02 nm / s to form a layer with a film thickness of 1 nm as the electron injection layer (EIL). Finally, on the electron injection layer, Al is evaporated at an evaporation rate of 0.5 nm / s to form a cathode with a film thickness of 100 nm.

[0238] Examples 12 to 16

[0239] Preparation of Organic Electroluminescent Devices 4 - 8 (OLED-4, OLED-5, OLED-6, OLED-7, and OLED-8)

[0240] OLED-4, OLED-5, OLED-6, OLED-7, and OLED-8 were prepared under the same production conditions as OLED-3, except that compounds 1-10, 1-20, 1-34, 1-36, and 1-37 described in Examples 4 - 8 were used as the doped luminescent materials respectively instead of compound 1-6 described in Example 3.

[0241] Comparative Example III and Comparative Example IV: Preparation of Comparative OLED-III and Comparative OLED-IV

[0242] Comparative OLED-III and Comparative OLED-IV were prepared under the same production conditions as OLED-3, except that commercial iridium complex Flrpic and known compound BP-DMAC were used as the doped luminescent materials respectively instead of compound 1-6 described in Example 3.

[0243] The formation method of each structural layer in the organic electroluminescent device of the present invention is not limited, and may include but not be limited to existing vacuum evaporation method, spin coating method, inkjet printing method, etc.

[0244] The structures and film thicknesses of each layer of the OLEDs prepared in Examples 9 - 16 and Comparative Examples I - IV of the present invention are shown in Table 1.

[0245] Table 1. Comparison of OLEDs in Examples 9 - 16 and Comparative Examples I - IV

[0246]

[0247] The structures of the compounds involved in Examples 9 - 16 and Comparative Examples I - IV are as follows:

[0248]

[0249] The current-voltage characteristics and luminescence characteristics of the organic light-emitting diodes in Examples 9 - 16 and Comparative Examples I - IV of the green light devices were tested using characterization equipment, and important parameters such as external quantum efficiency and lifetime were recorded (see Table 2).

[0250] As can be seen from Table 2, in Examples 9 and 10 where compound 1-1 and compound 1-3 of the present invention were used as the host materials respectively, compared with Comparative Examples I and II using commercial host materials, the external quantum efficiency and lifetime of the devices were improved to a certain extent.

[0251] As Examples 11 to 16 of the doped luminescent materials, Compounds 1-10, 1-20, 1-34, 1-36 and 1-37 of the present invention have significantly improved the external quantum efficiency and lifetime of the devices compared with Comparative Example III and Comparative Example IV using commercial iridium complex Flrpic and known compound BP-DMAC as the doped luminescent materials.

[0252] From the above comparison, it can be seen that the introduction of the hexamethylbiphenyl structural motif can effectively improve the performance of the materials and their devices, and the preparation cost of the hexamethylbiphenyl derivatives is relatively low.

[0253] Table 2. Comparison of OLED device performances in Examples 9 to 16 and Comparative Examples III to IV

[0254]

[0255]

[0256] The compounds of Example 6 and Example 7 (Compound 1-34 and 1-36) were doped into the host material bis[4-(9'-carbazolyl)phenyl]phenylphosphine oxide (BCPO) film at a concentration of 20%, and their steady-state photoluminescence spectra were measured. See Figure 1 It can be seen that Compound 1-34 emits strong blue-green light; Compound 1-36 emits strong yellow light.

[0257] The compounds of Example 6 and Example 7 (Compound 1-34 and 1-36) were subjected to thermogravimetric analysis (TGA). See Figure 3 As shown, the thermal decomposition temperatures of Compound 1-34 and 1-36 are 434 °C and 480 °C respectively, indicating that Compound 1-34 and 1-36 have excellent thermal stability.

[0258] The compounds of Example 6 and Example 7 (Compound 1-34 and 1-36) were tested by differential scanning calorimetry (DSC). The thermal decomposition temperatures of Compound 1-34 and 1-36 are 177 °C and 183 °C respectively, indicating that Compound 1-34 and 1-36 have excellent film-forming stability.

[0259] The electroluminescence spectra of the organic light-emitting devices (OLED-6 and OLED-7) of Example 14 and Example 15 were measured at different driving voltages. See Figure 5 As shown, at different voltages, they all have consistent electroluminescence spectra, indicating that the above devices have excellent luminescence color stability.

[0260] The efficiency-luminance of the organic light-emitting devices (OLED-6 and OLED-7) of Example 14 and Example 15 was measured. See Figure 6 It can be seen that the above devices have very high luminous efficiency.

[0261] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hexamethylbiphenyl derivative, characterized in that, the hexamethylbiphenyl derivative is selected from one of the following structures:

2. The hexamethylbiphenyl derivative according to claim 1, characterized in that, the hexamethylbiphenyl derivative is doped in the host material BCPO film at a concentration of 20%, and has a steady-state photoluminescence spectrum as shown in Figure 1.

3. The hexamethylbiphenyl derivative according to claim 1, characterized in that, the hexamethylbiphenyl derivative is doped in the host material BCPO film at a concentration of 20%, and has a transient spectrum as shown in Figure 2.

4. The hexamethylbiphenyl derivative according to any one of claims 1-3, characterized in that, the hexamethylbiphenyl derivative has a thermogravimetric analysis curve as shown in Figure 3.

5. The hexamethylbiphenyl derivative according to any one of claims 1-3, characterized in that, the hexamethylbiphenyl derivative has a differential scanning calorimetry curve as shown in Figure 4.

6. A preparation method of the hexamethylbiphenyl derivative according to any one of claims 1 to 5, which comprises the following steps: Compound M2 having the structure shown in formula (2) reacts with compounds having X 1 , X 2 , X 3 , X 4 groups to obtain the hexamethylbiphenyl derivative; In formula (2), X 5 is selected from halogen; X 1 , X 2 , X 3 , X 4 groups such as the substituents in Formulas 1-1 to 1-39.

7. Use of the hexamethylbiphenyl derivative according to any one of claims 1 to 5 in electronic devices.

8. The use according to claim 7, characterized in that, the hexamethylbiphenyl derivative is applied in organic light-emitting diodes, organic field-effect transistors and organic solar cells.

9. An electronic device, which comprises the hexamethylbiphenyl derivative according to any one of claims 1 to 5.

10. The electronic device according to claim 9, characterized in that, the electronic device comprises two electrodes and an organic layer located between the electrodes, and the organic layer comprises the above-mentioned hexamethylbiphenyl derivative.

11. The electronic device according to claim 10, characterized in that, the organic layer is one, two or more of an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

12. The electronic device according to claim 11, characterized in that, the hexamethylbiphenyl derivative is located in at least one of the injection layer, the transport layer, the light-emitting layer, and the blocking layer.

13. An organic light-emitting device, which comprises a first electrode and a second electrode arranged opposite to each other, and at least one organic layer is arranged between the first electrode and the second electrode, and the organic layer contains the hexamethylbiphenyl derivative according to any one of claims 1 to 5.

14. The organic light-emitting device according to claim 13, characterized in that, the organic layer includes one, two or more of an injection layer, a transport layer, a light-emitting layer, and a blocking layer.

15. The organic light-emitting device according to claim 14, characterized in that, the hexamethylbiphenyl derivative is located in at least one of the injection layer, the transport layer, the light-emitting layer, and the blocking layer.

16. The organic light-emitting device according to claim 14, characterized in that, the injection layer includes a hole injection layer and an electron injection layer, and the transport layer includes a hole transport layer and an electron transport layer; the blocking layer includes a hole blocking layer and an electron blocking layer.

17. The organic light-emitting device according to claim 14, characterized in that, The organic electroluminescent device has an electroluminescent spectrum at different driving voltages as shown in Figure 5, and the organic electroluminescent device has an efficiency-luminance curve as shown in Figure 6.

18. The organic electroluminescent device according to claim 14, wherein, the organic electroluminescent device includes: an anode, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, and a cathode sequentially arranged from bottom to top; or an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode sequentially arranged from bottom to top; or an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode sequentially arranged from bottom to top.

19. The organic electroluminescent device according to claim 18, wherein, the thickness of the hole injection layer is 0.5 - 15 nm, the thickness of the hole transport layer is 20 - 50 nm, the thickness of the electron blocking layer is 1 - 20 nm, the thickness of the light-emitting layer is 20 - 60 nm, the thickness of the hole blocking layer is 5 - 40 nm, the thickness of the electron transport layer is 20 - 60 nm, and the thickness of the electron injection layer is 0.5 - 1.5 nm.

20. The organic electroluminescent device according to claim 18, wherein, the thickness of the hole injection layer is 1 - 10 nm, the thickness of the hole transport layer is 30 - 40 nm, the thickness of the electron blocking layer is 5 - 15 nm, the thickness of the light-emitting layer is 25 - 35 nm, the thickness of the hole blocking layer is 10 - 20 nm, the thickness of the electron transport layer is 30 - 50 nm, and the thickness of the electron injection layer is 0.8 - 1 nm.

21. A method for manufacturing an organic electroluminescent device according to any one of claims 13 - 20, comprising the following steps: sequentially disposing an anode, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, and a cathode on a substrate; or sequentially disposing an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode on a substrate; or the organic electroluminescent device includes sequentially disposing an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode on a substrate from bottom to top.

22. The method for manufacturing an organic electroluminescent device according to claim 21, wherein, the anode, the hole injection layer, the hole transport layer, the electron blocking layer, the light-emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode are disposed by evaporation, spin coating, or inkjet printing.

23. The method for manufacturing an organic electroluminescent device according to claim 22, wherein, The evaporation coating is carried out under vacuum conditions, and is carried out under the condition that the vacuum degree is lower than 2×10 -5 Pa.

24. The method for manufacturing an organic electroluminescent device according to claim 23, wherein, the evaporation rate is 0.2 nm / s.

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