Triarylamine compounds and their applications in organic electroluminescent devices

Abstract

The application discloses a triarylamine compound and application thereof in an organic electroluminescent device, and has a chemical structure as shown in the formula (1), R1 and R2 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C10 straight chain or branched alkyl, a substituted or unsubstituted C3-C10 cycloalkyl, or a substituted or unsubstituted C6-C20 aryl, or are combined with each other to form a substituted or unsubstituted fluorene ring; only one of A1 to A3 is hydrogen, only one is selected from a group as shown in the formula (2), and only one is selected from a group as shown in the formula (3). The triarylamine compound of the application is simple in synthesis, stable in molecular structure, has excellent hole transport property and electron blocking capacity, can reduce the manufacturing cost of the organic electroluminescent device, and improve the luminous efficiency and service life of the device.

Description

Technical Field

[0001] The present invention relates to the field of organic electroluminescent materials, in particular to triarylamine compounds and applications thereof in organic electroluminescent devices. Background Art

[0002] Organic electroluminescent devices (OLEDs, or organic light-emitting diodes) are self-luminous electronic components with high contrast, wide viewing angles, fast response times, and excellent color reproduction. They can also be fabricated on flexible substrates to create rollable or bendable displays. Consequently, OLED displays have been widely used in consumer electronics such as mobile phones, tablets, and wall-mounted televisions, as well as in automotive displays.

[0003] OLED devices are mainly composed of three parts: electrodes, organic light-emitting layers and organic functional layers. Introducing suitable organic functional layer materials into the device can effectively improve the luminous efficiency of the device and reduce the power consumption of the device. For example, the typical organic electroluminescent device structure includes: anode / hole injection layer (HIL) / hole transport layer (HTL) / light-emitting layer (EML, light-emitting host material: light-emitting guest material) / electron transport layer (ETL) / electron injection layer (EIL) / cathode. The main function of the hole transport layer is to transport the holes injected from the anode to the light-emitting layer, and to block the electrons coming from the other side of the device, which plays an important role.

[0004] In the prior art, triarylamine compounds containing fluorene or fluorene derivatives are a common type of hole transport layer materials with excellent hole acceptance and transport properties. However, it is necessary to further develop new functional layer materials with excellent performance to meet the display industry's higher demands on device performance. Summary of the Invention

[0005] The purpose of the present invention is to provide a triarylamine compound and its application in an organic electroluminescent device, so as to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a triarylamine compound having a chemical structure as shown in formula (1):

[0007]

[0008] In formula (1), R1 and R2 are the same or different and are independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C10 straight or branched alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C6-C20 aryl group, or are combined with each other to form a substituted or unsubstituted fluorene ring;

[0009] Among A1 to A3, only one is hydrogen, only one is selected from the group represented by formula (2), and only one is selected from the group represented by formula (3):

[0010]

[0011] In formula (2), L0, L1, and L2 are the same or different and are each independently selected from a single bond, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C2-C20 heteroarylene group; Ar1 ​​and Ar2 are the same or different and are each independently selected from a substituted or unsubstituted C6-C40 aryl group, or a substituted or unsubstituted C2-C40 heteroaryl group;

[0012] In formula (3), Z1 and Z2 are the same or different and are independently selected from C(R3R4), N(R5), O or S; R3, R4, and R5 are the same or different and are independently selected from substituted or unsubstituted C1-C10 linear or branched alkyl, substituted or unsubstituted C3-C10 cycloalkyl, or substituted or unsubstituted C6-C20 aryl;

[0013] * indicates bonding site;

[0014] The term "substituted" in the context of "substituted or unsubstituted" means substituted by one or more substituents selected from deuterium, tritium, fluorine, cyano, nitro, trifluoromethyl, C1-C10 straight-chain or branched alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 alkylthio, C6-C20 aryl, and C2-C20 heteroaryl, and when there are multiple substituents, the multiple substituents may be the same or different.

[0015] The substituents of R1, R2, L0, L1, L2, Z1, Z2, Ar1 and Ar2 are the same as or different from each other.

[0016] Another aspect of the present invention provides an organic layer comprising the aforementioned triarylamine compound.

[0017] Another aspect of the present invention provides use of the aforementioned triarylamine compound and the aforementioned organic layer in an organic electroluminescent device.

[0018] Another aspect of the present invention provides an organic electroluminescent device comprising a first electrode, a second electrode and an organic layer, wherein the organic layer is at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron injection layer or an electron transport layer, and the organic layer comprises the aforementioned triarylamine compound.

[0019] Another aspect of the present invention provides a display or lighting device, comprising the organic electroluminescent device as described above in the present invention.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the triarylamine compounds of the present invention have good solubility, are easy to synthesize and purify, have high singlet and triplet energy levels, excellent hole transport properties and structural stability, and can achieve regulation of frontier orbital energy levels by connecting different aromatic groups, thereby being applied to hole transport layer materials for various colors of light, thereby improving the service life and luminous efficiency of the device and reducing the production cost of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a schematic structural diagram of an organic electroluminescent device in an embodiment;

[0022] Figure 2 is another structural schematic diagram of the organic electroluminescent device in the embodiment;

[0023] The reference numerals are as follows: 101 substrate; 102 first electrode; 103 hole injection layer; 104 first hole transport layer; 105 second hole transport layer; 106 light emitting layer; 107 hole blocking layer; 108 electron transport layer; 109 second electrode; 110 covering layer. DETAILED DESCRIPTION

[0024] The present invention provides a class of triarylamine compounds based on fluorene. A larger dibenzocycloalkyl or heterocycloalkyl structure is introduced on one side of the fluorene group to which the triarylamine is connected, which is beneficial to improving the triplet energy level of the molecule and can effectively block the excitons in the light-emitting layer from migrating to the hole transport layer, ensuring that the luminous efficiency of the device is not reduced. Secondly, in the dibenzocycloalkyl or heterocycloalkyl structure, the conjugation between the two benzene rings is interrupted by sp3 hybridized carbon atoms or heteroatoms, so that the fragment has weak conjugation and electron-donating properties. Introducing this fragment into the triarylamine structure based on fluorene not only makes the molecular structure more stable, but also helps holes to be transferred from one molecule to another more quickly, thereby facilitating the improvement of device life and the improvement of luminous efficiency. In addition, the dibenzocycloalkyl or heterocycloalkyl structure is a non-planar structure, which can inhibit the local formation of crystals during the molecular film formation process and is more inclined to form a uniform amorphous film, so that the film structure is more stable when the device is working, and is not easily affected by Joule heat and undergoes phase changes, which is beneficial to the improvement of device life. On this basis, the present invention was completed.

[0025] The present invention provides a triarylamine compound having a chemical structure as shown in formula (1):

[0026]

[0027] In formula (1), R1 and R2 are the same or different and are independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C10 straight or branched alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C6-C20 aryl group, or are combined with each other to form a substituted or unsubstituted fluorene ring;

[0028] Among A1 to A3, only one is hydrogen, only one is selected from the group represented by formula (2), and only one is selected from the group represented by formula (3):

[0029]

[0030]

[0031] In formula (2), L0, L1, and L2 are the same or different and are each independently selected from a single bond, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C2-C20 heteroarylene group; Ar1 ​​and Ar2 are the same or different and are each independently selected from a substituted or unsubstituted C6-C40 aryl group, or a substituted or unsubstituted C2-C40 heteroaryl group;

[0032] In formula (3), Z1 and Z2 are the same or different and are independently selected from C(R3R4), N(R5), O or S; R3, R4, and R5 are the same or different and are independently selected from substituted or unsubstituted C1-C10 linear or branched alkyl, substituted or unsubstituted C3-C10 cycloalkyl, or substituted or unsubstituted C6-C20 aryl;

[0033] * indicates bonding site;

[0034] The term "substituted" in "substituted or unsubstituted" means substituted by one or more substituents selected from deuterium, tritium, fluorine, cyano, nitro, trifluoromethyl, C1-C10 straight-chain or branched alkyl, C3-C10 cycloalkyl, C1-C10 alkoxy, C1-C10 alkylthio, C6-C20 aryl, and C2-C20 heteroaryl, and when there are multiple substituents, the multiple substituents may be the same or different.

[0035] The substituents of R1, R2, L0, L1, L2, Z1, Z2, Ar1 and Ar2 are the same as or different from each other.

[0036] In some embodiments, the chemical structure shown in formula (1) is represented by chemical formula (2-1) or (2-2):

[0037]

[0038] In chemical formulae (2-1) and (2-2), R1, R2, L0, L1, L2, Z1, Z2, Ar1, and Ar2 have the same meanings as those defined in chemical formula (1).

[0039] In some embodiments, the chemical structure shown in formula (1) is represented by chemical formula (3-1) or (3-2):

[0040]

[0041] In chemical formulae (3-1) and (3-2), R1, R2, L0, L1, L2, Z1, Z2, Ar1, and Ar2 have the same meanings as those defined in chemical formula (1).

[0042] In some embodiments, the chemical structure shown in formula (1) is represented by chemical formula (4-1) or (4-2):

[0043]

[0044] In chemical formulae (4-1) and (4-2), R1, R2, L0, L1, L2, Z1, Z2, Ar1, and Ar2 have the same meanings as those defined in chemical formula (1).

[0045] In some embodiments, the substituent represented by formula (3) is selected from at least one of the following groups:

[0046]

[0047] * indicates the bonding site.

[0048] In some embodiments, L0, L1, and L2 are the same as or different from each other, and are each independently selected from a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted dibenzothiophenylene group, or a substituted or unsubstituted dibenzofuranyl group; wherein, "substituted" in "substituted or unsubstituted" means substituted by one or more substituents selected from deuterium, tritium, fluorine, cyano, nitro, trifluoromethyl, methoxy, methylthio, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, tolyl, tert-butylphenyl, and naphthyl, and when there are multiple substituents, the multiple substituents are the same as or different from each other.

[0049] In some embodiments, Ar1, Ar2are the same or different from each other, each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted terphenylene, substituted or unsubstituted fluorenyl, substituted or unsubstituted spirofluorenyl, substituted or unsubstituted spirofluoro-xanthenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzoselenophenyl, substituted or unsubstituted benzofluorenyl, substituted or unsubstituted benzonaphthofuranyl, substituted or unsubstituted benzonaphthothiophenyl; wherein "substituted or unsubstituted" means "substituted" with one or more substituents selected from deuterium, tritium, fluorine, cyano, nitro, trifluoromethyl, methoxy, methylthio, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, tolyl, t-butylphenyl, naphthyl, and when multiple substituents are present, the multiple substituents are the same or different from each other.

[0050] In some embodiments, the triarylamine compound is selected from at least one of the following chemical structures:

[0051]

[0052]

[0053]

[0054]

[0055] In some embodiments, the triarylamine compound is selected from at least one of the following chemical structures:

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] In some embodiments, the triarylamine compound is selected from at least one of the following chemical structures:

[0062]

[0063]

[0064]

[0065]

[0066] The present invention also provides an organic electroluminescent device comprising a cathode, an anode, and a light-emitting layer between the cathode and the anode, wherein the triarylamine compound is contained in the organic layer between the anode and the light-emitting layer.

[0067] In some embodiments, the triarylamine compound is included in at least one of an electron blocking layer, a hole injection layer, a hole transport layer, and a layer that simultaneously transports and injects holes between the anode and the light-emitting layer.

[0068] In some embodiments, the triarylamine compound is contained in a hole transport layer provided between the anode and the light-emitting layer.

[0069] The present invention provides an organic electroluminescent device comprising a first electrode, a second electrode, and one or more organic layers disposed between the first and second electrodes, forming a bottom- or top-emitting device structure. The organic layer may be a single layer or a multilayer tandem structure comprising two or more organic layers. The organic layer may comprise at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron injection layer, or an electron transport layer. The device may be prepared using common methods and materials for preparing organic electroluminescent devices. The organic layer may comprise a triarylamine compound according to the present invention.

[0070] In the organic electroluminescent device provided by the present invention, the first electrode serves as the anode layer. The anode material may be, for example, a material with a large work function, which allows for smooth hole injection into the organic layer. Further examples include metals, metal oxides, combinations of metals and oxides, and conductive polymers. Examples of metal oxides include indium tin oxide (ITO), zinc oxide, indium oxide, and indium zinc oxide (IZO).

[0071] In the organic electroluminescent device provided by the present invention, the second electrode serves as the cathode layer. The cathode material can be, for example, a material with a low work function, allowing electrons to be smoothly injected into the organic layer. The cathode material can be, for example, a metal or a multilayer structure. The metal can be, for example, magnesium, silver, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, tin, and lead, or alloys thereof. The cathode material is preferably selected from magnesium and silver.

[0072] In the organic electroluminescent device provided by the present invention, the material of the hole injection layer is preferably a material whose highest occupied molecular orbital (HOMO) is between the work function of the anode material and the HOMO of the surrounding organic layer as a material that is advantageous in receiving holes from the anode at low voltage.

[0073] In the organic electroluminescent device provided by the present invention, the hole transport layer is a material having high hole mobility suitable for receiving holes from the anode or hole injection layer and transporting the holes to the light-emitting layer. Materials for the hole transport layer include, but are not limited to, organic materials containing arylamines, conductive polymers, and block copolymers having both conjugated and non-conjugated portions.

[0074] In the organic electroluminescent device provided by the present invention, the material of the light-emitting layer can generally be selected from materials with good quantum efficiency for fluorescence or phosphorescence as materials that can emit light in the visible light region by receiving holes and electrons from the hole transport layer and the electron transport layer respectively and combining the holes with the electrons.

[0075] In the organic electroluminescent device provided by the present invention, the material of the electron transport layer is a material having high electron mobility, which is suitable as a material that advantageously receives electrons from the cathode and transports the electrons to the light-emitting layer.

[0076] In the organic electroluminescent device provided by the present invention, the material of the cover layer generally has a high refractive index, and thus can help improve the light efficiency of the organic electroluminescent device, especially help improve the external light emitting efficiency.

[0077] In the organic electroluminescent device provided by the present invention, the organic electroluminescent device is an organic photovoltaic device, an organic light-emitting device, an organic solar cell, an electronic paper, an organic photoreceptor, an organic thin film transistor, etc.

[0078] Another aspect of the present invention provides a display or lighting device, comprising the aforementioned organic electroluminescent device of the present invention.

[0079] Unless otherwise specified, the compounds not described in the present invention are commercially available. Mass spectra were determined using a ZABHS mass spectrometer (manufactured by Micromass, UK), and nuclear magnetic resonance (NMR) was determined using a Bruker 400 MHz NMR spectrometer (manufactured by Bruker, Germany).

[0080] Synthesis Example:

[0081] The compounds involved in the present invention can be prepared by the following general synthetic routes, but are not limited thereto.

[0082]

[0083] Wherein, for compound iii, X1 and X2 are independently selected from iodine, bromine or chlorine. Preferably, when X2 is selected from iodine, X1 is selected from bromine or chlorine; when X2 is selected from bromine, X1 is selected from chlorine.

[0084] For compound v, when L0 is selected from a single bond, X3 is hydrogen; when L0 is not selected from a single bond, X3 is selected from a boronic acid group or a pinacol boronate group.

[0085] Furthermore, compound iii can be synthesized using a derivative of 9-fluorenone as a starting material. The specific synthetic route is as follows:

[0086] a. When R1 and R2 are each independently selected from substituted or unsubstituted alkyl or cycloalkyl, or substituted or unsubstituted aryl:

[0087]

[0088] Synthesis of compound vi:

[0089] Under a nitrogen atmosphere, elemental iodine (9.1 g, 36.0 mmol, 1.2 eq), hypophosphorous acid (4.6 g, 36.0 mmol, 50% wt in H2O, 1.2 eq) and glacial acetic acid (500 mL) were added to a three-necked flask in sequence, mixed thoroughly and stirred at 80°C for 30 minutes. Subsequently, compound v (30.0 mmol, 1 eq) was added to the reaction flask in batches under a nitrogen atmosphere, and the temperature was then raised to reflux and reacted for 12 hours. Thin layer chromatography analysis showed that there was essentially no raw material remaining, and heating was stopped. After the reaction system cooled to room temperature, the reaction solution was poured into a large amount of deionized water, and a large amount of white solid precipitated. The solid was collected by suction, washed with deionized water and dried to obtain compound vi. The obtained product was directly used in the next reaction.

[0090] Synthesis of compound iii:

[0091] Under a nitrogen atmosphere, compound vi (20.0 mmol, 1 eq) and anhydrous tetrahydrofuran (50 mL) were added to the reaction flask in sequence. After stirring evenly, the solution was cooled to 0°C and potassium tert-butoxide (2.2 g, 20.0 mmol, 1 eq) was added in batches under a nitrogen atmosphere. After the addition was completed, the reaction system was slowly returned to room temperature and stirred for 1.5 hours. Subsequently, the iodinated compound R1-I (20.0 mmol, 1 eq) was slowly added, and the reaction system was observed to become a milky white turbid liquid. At room temperature, the suspension was stirred under a nitrogen atmosphere for 2 hours, then filtered, the filtrate was collected, and the solvent was removed by distillation under reduced pressure. The obtained intermediate compound was further used as a reaction substrate, and the above experimental process was repeated, except that the iodinated compound R1-I was replaced equivalently with R2-I. The obtained crude product was purified by flash silica gel column chromatography (mobile phase was a mixed solvent of n-hexane / ethyl acetate) to obtain the target compound iii.

[0092] b. When R1 and R2 combine to form a substituted or unsubstituted fluorene ring (the unsubstituted fluorene ring is used as an example, and the substituted fluorene ring can be synthesized using the same operation):

[0093]

[0094] Under a nitrogen atmosphere, magnesium turnings (729 mg, 30.0 mmol, 1.5 eq) treated with saturated ammonium chloride solution, two iodine pellets, and anhydrous tetrahydrofuran (25 mL) were added to a dry three-necked flask (A). Stirring was initiated, and a solution of 2-bromobiphenyl (5.6 g, 24.0 mmol, 1.2 eq) in anhydrous tetrahydrofuran (40 mL) was added dropwise. After the addition was complete, the temperature was raised to reflux and the reaction was allowed to react for 3 hours. In another dry three-necked flask (B), compound vi (20 mmol, 1 eq) was dissolved in anhydrous tetrahydrofuran (40 mL) under a nitrogen atmosphere. Subsequently, under a nitrogen atmosphere, the freshly prepared Grignard reagent in flask (A) was transferred dropwise to flask (B) via a steel needle. After the addition was complete, the reaction solution in flask (B) was refluxed under a nitrogen atmosphere for 18 hours. Thin-layer chromatography analysis revealed virtually no residual starting material, and the majority of the solvent was removed by distillation. To the resulting crude product, dichloromethane (100 mL) and deionized water (100 mL) were added sequentially, stirred for 3 minutes, and then allowed to stand to separate. The mixture was separated using a separatory funnel, and the organic phase was retained. The aqueous phase was extracted with dichloromethane (3 × 40 mL), combined with the retained organic phase, dried over anhydrous magnesium sulfate, filtered, and the solvent was distilled off. The crude product was purified by flash silica gel column chromatography (mobile phase: n-hexane / dichloromethane mixed solvent) to obtain compound iii.

[0095] Specifically, in the compounds of the present invention, according to the different positions of the substituents in formula (2) and formula (3), the raw material compound vi (dihalogenated 9-fluorenone) used can be selected from the following compounds:

[0096]

[0097] Among them, compound vi-i (2-bromo-3-iodo-9-fluorenone) can be synthesized by referring to the method described in application publication number CN107573307A; compound vi-iv (3-bromo-2-iodo-9-fluorenone) can be synthesized by referring to the method described in non-patent literature Organic Letters (2022), 24(31), 5851-5854; compound vi-ii (4-bromo-2-chloro-9-fluorenone) and compound vi-ii (2-bromo-4-chloro-9-fluorenone) can be synthesized by referring to the method described in application publication number CN112552275A.

[0098] Synthesis of compound vi-iii (4-bromo-3-chloro-9-fluorenone):

[0099]

[0100] (1) Preparation of compound M1:

[0101] Under a nitrogen atmosphere, 1-bromo-2-chloro-6-iodobenzene (31.7 g, 100 mmol, 1 eq), 2-(methoxycarbonyl)phenylboronic acid (18.0 g, 100 mmol, 1 eq), tetrakis(triphenylphosphine)palladium (1155.6 mg, 1.0 mmol, 1% eq), potassium carbonate (20.7 g, 150 mmol, 1.5 eq), and anhydrous 1,4-dioxane (300 mL) were added sequentially to a three-necked flask. After stirring and mixing thoroughly, the temperature was raised to reflux. After 6 hours of reaction, thin-layer chromatography analysis revealed virtually no residual starting material. The solvent was then removed by vacuum distillation. Ethyl acetate (180 mL) and deionized water (120 mL) were added sequentially to the resulting residue, which was stirred for 5 minutes and allowed to stand for separation. The liquid was separated using a separatory funnel, and the organic phase was retained. The aqueous phase was extracted with ethyl acetate (3×50 mL), combined with the above-retained organic phase, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. The crude product was purified by flash silica gel column chromatography (mobile phase: n-hexane / ethyl acetate mixed solvent) to obtain intermediate compound M1 (27.5 g, yield 84.5%).

[0102] (2) Preparation of Compound M2:

[0103] In a three-necked flask, compound M1 (26.1 g, 80 mmol, 1 eq) was dissolved in tetrahydrofuran (150 mL). A solution of lithium hydroxide (5.7 g, 240 mmol, 3 eq) in water (70 mL of water) was added and stirred at room temperature for 6 hours. Thin-layer chromatography analysis revealed essentially no residual starting material. 6M hydrochloric acid was slowly added to the reaction system to adjust the pH to 1. The mixture was then extracted with ethyl acetate (2 x 250 mL). The resulting organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the solvent removed by distillation under reduced pressure to yield intermediate compound M2 (24.9 g). The crude product was used directly in the next reaction.

[0104] (3) Preparation of compound vi-iii (4-bromo-3-chloro-9-fluorenone):

[0105] In a three-necked flask, compound M2 (24.9 g, 80 mmol, 1 eq) was dissolved in dichloromethane (200 mL). The reaction system was then cooled to 0°C and polyphosphoric acid (PPA, 60 g) was added under vigorous stirring. The reaction system was then slowly warmed to room temperature and continued to stir vigorously at room temperature for 12 hours. Thin-layer chromatography analysis revealed essentially no residual starting material. Stirring was stopped, the organic phase was separated, and the organic phase was washed twice with a 1 M aqueous sodium hydroxide solution, then dried over anhydrous magnesium sulfate, filtered, and the solvent was distilled off. The crude product was purified by flash silica gel column chromatography (mobile phase: a mixed solvent of n-hexane / dichloromethane) to give 4-bromo-3-chloro-9-fluorenone (20.0 g, yield 85.2%).

[0106] The synthesis method of compound vi-vi (3-bromo-4-chloro-9-fluorenone) can refer to 4-bromo-3-chloro-9-fluorenone, except that the starting material 1-bromo-2-chloro-3-iodobenzene is used to replace 1-bromo-2-chloro-6-iodobenzene in an equivalent amount.

[0107] Synthesis of compound H2:

[0108]

[0109] (1) Synthesis of compound ii-H2:

[0110] Under a nitrogen atmosphere, compound i-H2 (15.8 g, 50.0 mmol, 1 eq), pinacol diboron (17.8 g, 70.0 mmol, 1.4 eq), potassium acetate (14.7 g, 150.0 mmol, 3 eq), and anhydrous 1,4-dioxane (200 mL) were added sequentially to a dry three-necked flask. After thorough mixing, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (1.8 g, 2.5 mmol, 5% eq) was added. After stirring, the reaction system was heated to reflux under a nitrogen atmosphere. After 4 hours of reaction, thin-layer chromatography analysis revealed virtually no residual starting material, and heating was discontinued. After the reaction system cooled to room temperature, ethyl acetate (150 mL) and deionized water (100 mL) were added to the reaction flask, stirred for 3 minutes, and allowed to stand for stratification. The liquid was separated using a separatory funnel, and the organic phase was retained. The aqueous phase was extracted with ethyl acetate (3×40 mL), combined with the above-retained organic phase, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. The crude product was purified by flash silica gel column chromatography (mobile phase: n-hexane / ethyl acetate mixed solvent) to obtain compound ii-H2 (17.0 g, yield 93.8%).

[0111] (2) Synthesis of compound iv-H2:

[0112] To a dry three-necked flask, under nitrogen atmosphere, were added compound ii-H2 (14.5 g, 40.0 mmol, 1 eq), compound iii-H2 (16.0 g, 40.0 mmol, 1 eq) and degassed toluene (200 mL) successively. After stirring well, tetrakis(triphenylphosphine)palladium (924.4 mg, 0.8 mmol, 2% eq), potassium carbonate (13.8 g, 100.0 mmol, 2.5 eq), degassed ethanol (120 mL) and deionized water (80 mL) were added successively. After stirring well, the reaction system was heated to reflux under nitrogen atmosphere. After 8 hours of reaction, TLC analysis showed that the starting material was substantially consumed, and the heating was stopped. When the reaction system was cooled to room temperature, 100 mL of toluene was added, stirred for 3 minutes, and then allowed to stand to separate the layers. The organic phase was retained, and the aqueous phase was extracted with toluene (3 x 40 mL). The organic phases were combined and dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. The crude product was purified by flash silica gel column chromatography (mobile phase: n-hexane / dichloromethane mixture) to obtain compound iv-H2 (16.3 g, yield 80.3%).

[0113] (3) Synthesis of target compound H2:

[0114] To a three-necked flask, under nitrogen atmosphere, were added compound iv-H2 (10.2 g, 20.0 mmol, 1 eq), bis(4-biphenyl)amine (compound v-H2, 6.4 g, 20.0 mmol, 1 eq) and anhydrous toluene (120 mL) successively. After stirring well, sodium tert-butoxide (2.9 g, 30.0 mmol, 1.5 eq), bis(dibenzylideneacetone)palladium (113.2 mg, 0.2 mmol, 1% eq) and tri-tert-butylphosphine (1.0 mL, 10% n-hexane solution, 0.4 mmol, 2% eq) were added successively. After stirring, the reaction system was mixed well and heated to reflux under nitrogen atmosphere. After 8 hours of reaction, TLC analysis showed that the starting material was substantially consumed, and the heating was stopped. When the temperature of the reaction system decreased to room temperature, a mixture of 5 mL of concentrated hydrochloric acid (37% aqueous solution) and 100 mL of deionized water was added, allowed to stand to separate the layers, and the organic phase was retained. The aqueous phase was extracted with toluene (3 x 30 mL), and the organic phases were combined. The solvent was removed by distillation under reduced pressure. The crude product was purified by silica gel column chromatography (mobile phase: n-hexane / toluene mixture) and recrystallization from a mixture of toluene / ethanol to obtain target compound H2 (11.0 g, yield 75.3%). Mass (m / z) = 748.39 [M+H] + . Total yield of three-step reaction 55.4%.

[0115] Referring to the above preparation method, the compounds (x) listed in Table 1 were synthesized, except that the starting compounds i-x, iii-x, v-x were used instead of compound i-H2 iii-H2, v-H2, respectively. Among them, the main raw materials used, the intermediates synthesized, the yield and the mass spectrometry characterization data are shown in Table 1.

[0116] Table 1

[0117]

[0118]

[0119]

[0120]

[0121] Synthesis of compound H100:

[0122]

[0123] First, referring to the synthesis method of compound iv-H2, the intermediate compound iv-H100 was obtained by two-step reaction; then, referring to the preparation method of compound iv-H100 synthesized by using compound ii-H100 and compound iii-H100 as raw materials, the final target product H100 was synthesized, except that the two raw materials containing boron and halogen were replaced by compound v-H100 and iv-H100, respectively. Mass spectrum (m / z) = 847.36 [M+H] + The total yield of three-step reaction was 54.3%.

[0124] Referring to the above preparation method, the compounds (x) listed in Table 2 were synthesized, except that the starting compounds i-x, iii-x, v-x were used instead of compound i-H100 iii-H100, v-H100. Among them, the main raw materials used, the intermediates synthesized, the yield and the mass spectrometry characterization data are shown in Table 2.

[0125] Table 2

[0126]

[0127]

[0128] The nuclear magnetic resonance data of representative compounds involved in the synthesis examples are shown in Table 3.

[0129] Table 3

[0130]

[0131]

[0132] Device Example:

[0133] The compounds used in the device are all purified by sublimation, and the purity is greater than 99.98%.

[0134] The compound involved in the present invention can be used as a hole transport layer material or an electron blocking layer material for OLED devices with various colors such as red light and green light. The specific device manufacturing method and test results are given below.

[0135] Preparation of red organic electroluminescent devices

[0136] Red light device embodiment 1:

[0137] According to Figure 1 The structure shown is used to make a red bottom-emitting organic electroluminescent device. The preparation process is as follows: On a glass substrate 101, a transparent ITO film layer (thickness 150nm) is formed by magnetron sputtering to obtain a first electrode 102 as an anode. A mixed material of compound 1 and compound 2 is evaporated on the surface of the anode as a hole injection layer 103, with a mixing ratio of 3:97 (mass ratio) and a thickness of 10nm; then compound 2 (thickness 100nm) and compound H2 of the present invention (thickness 20nm) are sequentially evaporated on the surface of the hole injection layer to obtain a first hole transport layer 104 and a second hole transport layer 105, respectively. Next, on the surface of the second hole transport layer 105, compound 3 and compound 4 are co-evaporated at a mass ratio of 95:5 to form an organic light-emitting layer 106 (thickness 40nm). Subsequently, compound 5 was sequentially evaporated on the surface of the organic light-emitting layer to form a hole-blocking layer 107 (10 nm thick), and compound 6 and LiQ were mixed in a 4:6 ratio (by mass) to form an electron-transporting layer 108 (30 nm thick). Finally, magnesium (Mg) and silver (Ag) were mixed and deposited on the surface of the electron-transporting layer 108 at a rate of 1:9 to form a 10 nm thick second electrode 109, which served as the cathode, completing the fabrication of the organic light-emitting device.

[0138] The chemical structures of compounds 1 to 6 and LiQ are shown in Table 4.

[0139] Table 4

[0140]

[0141] Red Light Device Examples 2-24

[0142] The organic electroluminescent device was prepared by the same method as in Example 1 of the red light device, except that the compound H2 was replaced by the compounds in Table 5 below when forming the light-emitting layer.

[0143] Comparative Examples 1-2

[0144] The organic electroluminescent device was prepared by the same method as in Example 1 of the red light device, except that compound HT-A and compound HT-B (chemical structures shown below) were used instead of compound H2 when forming the light-emitting layer.

[0145]

[0146] The operating voltage and efficiency of the organic electroluminescent devices prepared above were calculated using a computer-controlled Keithley 2400 test system. Device lifetimes under dark conditions were measured using a Polaronix (McScience Co.) lifetime measurement system equipped with a power supply and a photodiode as a detection unit. Each set of red light device examples was produced and tested in the same batch as the devices of Comparative Example 1. The operating voltage, efficiency, and lifetime of the devices of Comparative Example 1 were each recorded as 1. The ratios of the corresponding indicators for the red light device examples 1-24 to those of the devices of Comparative Example 2 were calculated, as shown in Table 5.

[0147] Table 5

[0148]

[0149]

[0150] Preparation of green organic electroluminescent devices

[0151] Green light device embodiment 1:

[0152] According to Figure 2The structure shown is used to make a green bottom-emitting organic electroluminescent device. The preparation process is as follows: On a glass substrate 101, a transparent ITO film layer (thickness 150nm) is formed by a magnetron sputtering process to obtain a first electrode 102 as an anode. A mixed material of compound 1 and compound 2 is evaporated on the surface of the anode as a hole injection layer 103, with a mixing ratio of 3:97 (mass ratio) and a thickness of 10nm; then compound 2 (thickness 100nm) and compound H16 of the present invention (thickness 40nm) are sequentially evaporated on the surface of the hole injection layer to obtain a first hole transport layer 104 and a second hole transport layer 105, respectively. Next, on the surface of the second hole transport layer 105, compound 3-3A, compound 3-3B and compound 3-4 are co-evaporated in a mass ratio of 45:45:10 to form an organic light-emitting layer 106 (thickness 40nm). Subsequently, compound 5 was sequentially evaporated on the surface of the organic light-emitting layer to form a hole-blocking layer 107 (10 nm thick), and compound 6 and LiQ were mixed in a 4:6 ratio (by mass) to form an electron-transporting layer 108 (30 nm thick). Finally, magnesium (Mg) and silver (Ag) were mixed and deposited on the surface of the electron-transporting layer 108 at a rate of 1:9 to form a 10 nm thick second electrode 109, which served as the cathode, completing the fabrication of the organic light-emitting device.

[0153] The chemical structures of compounds 1, 5, 6, 7 and LiQ are described above, and the chemical structures of compounds 3-3A, 3-3B and 3-4 are shown in Table 6.

[0154] Table 6

[0155]

[0156] Green Light Device Examples 2 to 15

[0157] The organic electroluminescent device was prepared by the same method as in Example 1 of the green light device, except that the compounds in Table 7 below were used instead of Compound H13 during the formation of light emission.

[0158] Comparative Example 3

[0159] In addition to forming the light-emitting layer, the compound HT-C Except for replacing compound H13, an organic electroluminescent device was prepared by the same method as in Example 1 of the green light device.

[0160] The operating voltage and efficiency of the organic electroluminescent devices prepared above were calculated using a computer-controlled Keithley 2400 test system. Device lifetimes in the dark were measured using a Polaronix (McScience Co.) lifetime measurement system equipped with a power supply and a photodiode as a detection unit. Each set of Example devices was produced and tested in the same batch as the devices of Comparative Example 3. The operating voltage, efficiency, and lifetime of the devices of Comparative Example 3 were each recorded as 1. The ratios of the corresponding indicators for the green light devices of Examples 1-12 to those of Comparative Example 3 were calculated, as shown in Table 7.

[0161] Table 7

[0162] Second hole transport layer Relative working voltage Relative efficiency Relative lifespan Comparative Example 3 HT-C 1 1 1 Green light device embodiment 1 H13 0.924 1.168 1.346 Green light device embodiment 2 H71 0.933 1.179 1.251 Green light device embodiment 3 H74 0.909 1.155 1.268 Green Light Device Example 4 H252 0.950 1.240 1.235 Green light device embodiment 5 H258 0.932 1.159 1.187 Green Light Device Example 6 H269 0.913 1.207 1.280 Green Light Device Example 7 H271 0.918 1.219 1.306 Green Light Device Example 8 H285 0.905 1.116 1.336 Green Light Device Example 9 H291 0.940 1.090 1.310 Green Light Device Example 10 H308 0.902 1.133 1.282 Green Light Device Example 11 H319 0.918 1.167 1.247 Green Light Device Example 12 H321 0.942 1.235 1.181 Green Light Device Example 13 H332 0.901 1.136 1.304 Green Light Device Example 14 H359 0.927 1.247 1.267 Green Light Device Example 15 H360 0.917 1.237 1.254

[0163] Referring to Table 5, it can be seen that in Examples 1 to 24 of the red light devices using the compounds of the present application as the second hole transport layer material of the organic electroluminescent red light device, compared with Comparative Examples 1 to 2, the device voltage is reduced by at least 4.5%, the device efficiency is increased by at least 15.2%, and the life is increased by at least 20.5%.

[0164] Referring to Table 7, it can be seen that in green light device Examples 1 to 12 using the compound of the present application as the second hole transport layer material of the organic electroluminescent green light device, compared with Comparative Examples 1 to 3, the device voltage is reduced by at least 5.0%, the device efficiency is increased by at least 9.0%, and the life is increased by at least 18.1%.

[0165] Compared to Comparative Examples 1 and 3, the fluorene groups in the present invention exhibit a weaker conjugation effect and ability to attract electron clouds. The electron distribution on the CN bond of the triarylamine is more even, making the CN bond less susceptible to breakage. This results in greater molecular stability and improved device lifespan. In Comparative Example 2, however, the fluorene portion of the spirofluorene xanthene group is not located on the conjugated plane of the molecule and thus largely does not participate in hole transport. This may be the cause of the higher device voltage and lower luminous efficiency.

[0166] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A triarylamine compound, characterized in that: At least one selected from the following chemical structures:

2. An organic electroluminescent device, characterized in that: The invention comprises a cathode, an anode, and a light-emitting layer between the cathode and the anode, wherein the triarylamine compound according to claim 1 is contained in an organic layer between the anode and the light-emitting layer.

3. The organic electroluminescent device according to claim 2, characterized in that: The triarylamine compound is contained in at least one layer of an electron blocking layer, a hole injection layer, a hole transport layer, and a layer that simultaneously transports and injects holes, which is provided between the anode and the light-emitting layer.

4. The organic electroluminescent device according to claim 3, characterized in that: The triarylamine compound is contained in a hole transport layer between the anode and the light-emitting layer.

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