A compound and its application

Abstract

The present invention relates to a compound and its application, wherein the compound has a structure shown in Formula I, and a naphthalene ring structure is introduced in the para position of aromatic amine to increase the molecular conjugation system, which is beneficial to strengthen the transmission of charge and improve the charge mobility of the molecule; at the same time, a condensed aromatic ring of a specific structure is introduced in the ortho position of aromatic amine, which can first increase the conjugation level of the entire molecule and improve the injection and transmission capacity of holes; secondly, the steric hindrance of the molecule can be increased to prevent the molecule from being excessively planarized and forming crystals at high temperatures. The compound of Formula I exhibits good hole injection and migration performance, and when it is used as a hole transport material or electron blocking material in an organic electroluminescent device, the efficiency roll-off of the device can be suppressed, and the hole injection and migration efficiency in the device can be effectively improved, thereby ensuring that the device obtains the excellent effect of low starting voltage and prolonging the life of the device.

Description

Technical Field

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

[0002] OLED (organic light-emitting diode) refers to the phenomenon that organic functional materials emit light under the action of electric field and are stimulated by current and voltage. It is a process that directly converts electrical energy into light energy. In 1979, Dr. Deng Qingyun, the "Father of OLED", accidentally discovered the electroluminescent properties of organic thin film devices in the laboratory, which opened the prelude to the research of OLED devices and made great contributions to the practical application of OLED technology. OLED devices are all-solid-state self-luminous devices with the characteristics of fast response speed, wide viewing angle, and wide operating temperature range. Organic light-emitting materials can be structurally designed and improved according to the requirements of use, and theoretically can achieve full-color output. Compared with liquid crystal display technology, OLED devices have a simpler structure and can realize ultra-thin large-area flat-panel displays. They are more lightweight, flexible, and foldable, making them more widely used.

[0003] With the advent of the 5G ultra-high-speed network communication era, human demand for information will explode, and the requirements for randomness and timeliness of information acquisition will become higher and higher. Portable, large-size display technology is a necessary condition to meet this demand. From the current technological development, organic light-emitting diodes (OLEDs) with organic semiconductors as functional materials are the most promising. This is attributed to the advantages of OLED technology, such as wide viewing angle, fast response speed, low driving voltage, wide adaptable display temperature range, and full-color display in the blue to red spectral region. In particular, devices can be made on flexible substrates, making large-area display portable possible.

[0004] However, there are still some problems in OLED display technology, such as high device driving voltage, low luminous efficiency, short display life, etc., which seriously affect the further development of this technology in practical fields. Therefore, continuous efforts are needed to continuously develop excellent performance materials that can improve device efficiency, life and reduce driving voltage.

[0005] In organic light-emitting devices, the materials used as organic layers can be roughly divided into luminescent materials, hole injection materials, hole transport materials, electron transport materials, etc. according to their functions. According to the luminescence mechanism, they can be divided into fluorescent materials that emit light through the singlet excited state of electrons and phosphorescent materials that emit light through the triplet excited state of electrons. In order to effectively alleviate the aggregation of luminescent materials and triplet excitons and avoid concentration quenching, a host-guest doping system in which the luminescent material is doped in the host material is usually adopted. The excitons generated by the host are transmitted to the dopant, thereby emitting light with high efficiency.

[0006] Organic hole materials play an important role in transferring holes injected from the anode to the light-emitting layer. Hole transport materials with excellent hole mobility are beneficial to the injection balance of carriers in the device, thereby reducing the device driving voltage. On the other hand, in order to prevent the excitons generated in the light-emitting layer from diffusing to the hole transport layer, resulting in color cast and reduced luminous efficiency, an electron blocking layer is also required to block the excitons from diffusing outward, prevent efficiency roll-off and improve the stability of the device.

[0007] Therefore, there is an urgent need to develop higher performance OLED materials in this field to improve the performance of the device. Summary of the invention

[0008] The object of the present invention is to provide a compound having excellent hole transporting ability and electron blocking ability.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] The present invention provides a compound having a structure shown in Formula I;

[0011]

[0012] In Formula I, X is selected from CR 4 R 5 or SiR 6 R 7 ;

[0013] The R 4 and R 5each independently selected from substituted or unsubstituted C1-C18 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) chain alkyl, substituted or unsubstituted C3-C18 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) cycloalkyl, substituted or unsubstituted C1-C12 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.) alkoxy, substituted or unsubstituted C3-C C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryl, substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryl, substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryloxy, or substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryloxy;

[0014] The R 6 and R 7 each independently selected from substituted or unsubstituted C1-C18 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) chain alkyl, substituted or unsubstituted C3-C18 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) cycloalkyl, substituted or unsubstituted C1-C12 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.) alkoxy, substituted or unsubstituted C6-C C3-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryl, substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryl, substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryloxy, or substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryloxy;

[0015] The R 4 and R 5 The R6 and R 7 Connected into a ring by chemical bonds or not connected into a ring;

[0016] In Formula I, the L 1 and L 2 Each is independently selected from a single bond, a substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) arylene group, or a substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroarylene group;

[0017] In Formula I, Ar 1 and Ar 2 Each is independently selected from substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryl or substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryl;

[0018] In Formula I, the R 1 , R 2 and R 3each independently selected from substituted or unsubstituted C1-C18 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) chain alkyl, substituted or unsubstituted C3-C18 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, etc.) cycloalkyl, substituted or unsubstituted C1-C18 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, etc.) alkoxy, halogen, cyano, nitro, hydroxy, C1-C18 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, etc.) , C12, C13, C14, C15, C16, C17, etc.) silyl, amino, substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) aryl, substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroaryl, substituted or unsubstituted C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) arylamino, or substituted or unsubstituted C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) heteroarylamino;

[0019] In Formula I, a is an integer of 0 to 7, such as 1, 2, 3, 4, 5, 6, etc., m is an integer of 0 to 3, such as 1, 2, etc., and n is an integer of 0 to 4, such as 1, 2, 3, etc.;

[0020] When a is an integer from 2 to 7, 2 to 7 R 1 Same or different;

[0021] When m is 2 or 3, 2 or 3 R 2 Same or different;

[0022] When n is an integer from 2 to 4, 2 to 4 R 3 Same or different;

[0023] When the above groups have substituents, the substituents are selected from halogen, C1-C12 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, etc.) chain alkyl, C3-C12 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, etc.) cycloalkyl, C1-C6 (e.g., C2, C3, C4, C5, etc.) alkoxy, C1-C6 (e.g., C2, C3, C4, C5, etc.) thioalkoxy, C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) arylamino, C3-C30 (e.g., C4, C6, C8, C12, C15 , C18, C20, C23, C25, C28, etc.) heteroarylamino, C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) monocyclic aryl, C10-C30 (e.g., C12, C14, C16, C18, C20, C26, C28, etc.) condensed ring aryl, C3-C30 (e.g., C4, C6, C8, C12, C15, C18, C20, C23, C25, C28, etc.) monocyclic heteroaryl, C6-C30 (e.g., C10, C12, C14, C16, C18, C20, C26, C28, etc.) condensed ring heteroaryl, or a combination of at least two of them. The above-mentioned "substituted or unsubstituted" group may be substituted with one substituent or with multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the present invention involves the same expression, they all have the same meaning and are not described one by one.

[0024] In the present invention, the heteroatom of the heteroaryl group is usually selected from N, O, and S.

[0025] In the present invention, the expression of a ring structure crossed by “—” indicates that the connection site is at any position on the ring structure that can form a bond.

[0026] The present invention provides a novel compound, wherein the general formula adopts a specific naphthalene ring structure introduced at the para position of aromatic amine, the naphthalene has good planarity, has excellent photoelectric properties, increases the molecular conjugated system, is conducive to strengthening the transmission of charges, and improves the charge mobility of the molecule; at the same time, a condensed aromatic ring with a specific structure is introduced at the ortho position of aromatic amine. First, the conjugation level of the entire molecule can be increased, and the hole injection and transport capabilities can be improved; secondly, the steric hindrance of the molecule can be increased to prevent the molecule from being overly planarized and forming crystals at high temperatures. The above two structural characteristics can make the molecule as a whole show good hole injection and migration performance. Therefore, when the compound of the present invention is used as a hole transport material or electron blocking material in an organic electroluminescent device, the efficiency roll-off of the device can be suppressed, and the hole injection and migration efficiency in the device can be effectively improved, thereby ensuring that the device obtains the excellent effect of low starting voltage and prolonging the life of the device.

[0027] In addition, the preparation process of the compound of the present invention is simple and easy, the raw materials are easily available, and it is suitable for mass production and expansion.

[0028] Preferably, the compound has a structure shown in formula (2-1) or formula (2-2);

[0029]

[0030] X, L 1 , L 2 ,Ar 1 ,Ar 2 , R 1 , R 2 , R 3 , a, m and n have the same meanings as in Formula I.

[0031] At least one of a, m and n is 0;

[0032] Preferably, a is 0.

[0033] Preferably, a, m and n are all 0.

[0034] Preferably, the compound has a structure shown in formula (3-1) or formula (3-2);

[0035]

[0036] X, L 1 , L 2 ,Ar 1 and Ar 2 All have the same meanings as in Formula I.

[0037] Preferably, X is CR 4 R 5 , the R 4 and R 5 All have the same meanings as in Formula I.

[0038] Preferably, the R 4 and R 5Each is independently selected from a substituted or unsubstituted C1-C6 chain alkyl group, a substituted or unsubstituted C3-C8 cycloalkyl group, or a substituted or unsubstituted C3-C30 heteroaryl group.

[0039] Preferably, the R 4 and R 5 Each is independently selected from substituted or unsubstituted C1-C6 chain alkyl groups.

[0040] Preferably, the R 4 and R 5 All are methyl.

[0041] Preferably, the R 6 and R 7 Each is independently selected from a substituted or unsubstituted C1-C6 chain alkyl group, a substituted or unsubstituted C3-C8 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C3-C30 heteroaryl group.

[0042] Preferably, the Ar 1 and Ar 2 Each is independently selected from one of the following substituted or unsubstituted groups: phenyl, naphthyl, anthracenyl, benzanthryl, phenanthryl, triphenylenyl, pyrenyl, fluoranthenyl, tetraphenyl, pentacene, benzopyrenyl, biphenyl, terphenyl, triphenylene, quaterphenyl, fluorenyl, benzofluorenyl, indolofluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis-indenofluorenyl, trans-indenofluorenyl, trimer Indenyl, isotrimeric indenyl, spirotrimeric indenyl, spiroisotrimeric indenyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzodibenzofuranyl, fluorenylbenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, benzodibenzothienyl, fluorenylbenzothienyl, acridinyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, phenothiazinyl or phenoxazinyl.

[0043] Preferably, the L 1 and L 2 Each is independently selected from a single bond or a substituted or unsubstituted C6-C30 arylene group.

[0044] Preferably, the L 1 and L 2 Each is independently selected from a single bond or a phenylene group.

[0045] Preferably, the compound has any one of the structures shown in C1-C89, D1-D85, E1-E89 and F1-F85 below:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] The second object of the present invention is to provide an application of the compound described in the first object, wherein the compound is applied to an organic electroluminescent device.

[0063] Preferably, the compound is used as a hole transport material or an electron blocking material for an organic electroluminescent device.

[0064] The third object of the present invention is to provide an organic electroluminescent device, comprising a substrate, a first electrode, a second electrode and at least one organic layer located between the first electrode and the second electrode, wherein the organic layer contains at least one compound described in one of the objects.

[0065] Preferably, the organic layer comprises a hole transport layer, and the hole transport layer comprises at least one compound described in one of the purposes.

[0066] Preferably, the organic layer comprises an electron blocking layer, and the electron blocking layer comprises at least one compound described in one of the purposes.

[0067] In a specific embodiment of the present invention, the OLED includes a first electrode, a second electrode, and an organic material layer between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0068] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0069] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode is used as an anode, an oxide transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. When the first electrode is used as a cathode, a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and any combination thereof can be used.

[0070] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0071] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) of a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multi-layer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0072] In one aspect of the present invention, the material of the hole transport region can be selected from one or more compounds shown in formula I of the present invention, and the electron blocking layer of the hole transport region may be absent or present and is selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-34 below; or any combination thereof.

[0073]

[0074]

[0075] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-34 mentioned above, or one or more compounds of HI-1 to HI-3 below; or one or more compounds of HT-1 to HT-34 can be doped with one or more compounds of HI-1 to HI-3 below.

[0076]

[0077] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit different wavelength spectra, and may also include a host material (Host). The light-emitting layer can be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors can be arranged in a plane according to a pixel pattern, or they can be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they can be separated from each other or connected to each other. The light-emitting layer can also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0078] According to different technologies, the light-emitting layer material can be made of different materials such as fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescent materials. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0079] In one aspect of the present invention, the light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent host material of the light-emitting layer can be selected from, but not limited to, one or more combinations of BFH-1 to BFH-17 listed below.

[0080]

[0081] In one aspect of the present invention, the light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of BFD-1 to BFD-12 listed below.

[0082]

[0083] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology, and the main material of the light-emitting layer is selected from, but not limited to, one or more combinations of GPH-1 to GPH-80.

[0084]

[0085]

[0086]

[0087]

[0088] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0089]

[0090]

[0091] Where D is deuterium.

[0092] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0093]

[0094] In one aspect of the present invention, the light-emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of YPD-1 to YPD-11 listed below.

[0095]

[0096] In one aspect of the present invention, the light-emitting layer adopts the technology of thermally activated delayed fluorescence luminescence. The fluorescent dopant of the light-emitting layer can be selected from, but not limited to, one or more combinations of TDE-1 to TDE-39 listed below.

[0097]

[0098]

[0099] In one aspect of the present invention, the light-emitting layer adopts the technology of thermally activated delayed fluorescence luminescence, and the main material of the light-emitting layer is selected from, but not limited to, one or more combinations of TDH1 to TDH24.

[0100]

[0101]

[0102] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0103] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-57 listed below.

[0104]

[0105]

[0106]

[0107] The device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes but is not limited to one or more combinations of the following: LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li or Ca.

[0108] Compared with the prior art, the present invention has the following beneficial effects:

[0109] The present invention provides a novel compound, the general formula adopts a specific naphthalene ring structure introduced in the para position of aromatic amine, the naphthalene has good planarity, has excellent photoelectric properties, increases the molecular conjugated system, is conducive to strengthening the transmission of charges, and improves the charge mobility of the molecule; at the same time, the introduction of a condensed aromatic ring of a specific structure in the ortho position of aromatic amine can first increase the conjugation level of the entire molecule and improve the injection and transmission capacity of holes; secondly, it can increase the steric hindrance of the molecule to prevent the molecule from being excessively planarized and forming crystals at high temperatures. The structural characteristics of the above two aspects can make the molecule as a whole show good hole injection and migration performance. Therefore, when the compound of the present invention is used as a hole transport material or an electron blocking material in an organic electroluminescent device, the efficiency roll-off of the device can be suppressed, and the hole injection and migration efficiency in the device can be effectively improved, thereby ensuring that the device obtains the excellent effect of low starting voltage and prolongs the life of the device.

[0110] In addition, the preparation process of the compound of the present invention is simple and easy, the raw materials are easily available, and it is suitable for mass production and expansion. DETAILED DESCRIPTION

[0111] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0112] The compound of the general formula I of the present invention can be synthesized by referring to the following synthetic route:

[0113]

[0114] The specific preparation method of the above-mentioned novel compound of the present invention will be described in detail below by taking a plurality of synthesis examples as examples, but the preparation method of the present invention is not limited to these synthesis examples.

[0115] Various chemicals used in the present invention, such as petroleum ether, ethyl acetate, sodium sulfate, toluene, tetrahydrofuran, dichloromethane, acetic acid, potassium carbonate and other basic chemical raw materials, were purchased from Shanghai Titan Technology Co., Ltd. and Xilong Chemical Co., Ltd. The mass spectrometer used to determine the following compounds was a ZAB-HS mass spectrometer (manufactured by Micromass, UK).

[0116] The synthesis method of the intermediate is as follows:

[0117] Synthesis of intermediate M1:

[0118]

[0119] Synthesis of compound M1-1

[0120] The raw materials 2-bromo-4-iodoaniline (50.0g, 168mmol), 1-naphthaleneboric acid (31.8g, 185mmol), potassium carbonate (17.8g, 201mmol) were placed in a three-necked flask containing 500mL toluene, 200mL ethanol and 200mL water, and stirred well. Then the air on the flask was replaced with nitrogen three times. Tetrakistriphenylphosphine palladium (1.94g, 1.68mmol) was added to the reaction solution under nitrogen protection, and then the temperature was raised to 100°C and the reaction was carried out for 18h. After cooling, the reaction solution was poured into a saturated aqueous ammonium chloride solution, extracted with ethyl acetate (500mL, three times), the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a dark brown oil. The crude product was purified by silica gel chromatography (petroleum ether / ethyl acetate, 10 / 1) to obtain 45g of a yellow solid, i.e., compound M1-1, with a yield of 89%.

[0121] Synthetic intermediate M1

[0122] The compound M1-1 (45.0 g, 151 mmol), 9,9-dimethylfluorene-2-boric acid (39.5 g, 166 mol), potassium carbonate (25.0 g, 181 mmol) synthesized in the previous step were placed in a three-necked flask containing 500 mL toluene, 200 mL ethanol and 200 mL water, and stirred well. Then, the air on the flask was replaced with nitrogen three times. Under nitrogen protection, tetrakistriphenylphosphine palladium (1.74 g, 1.51 mmol) was added to the reaction solution, and then the temperature was raised to 100 ° C and reacted for 18 hours. After cooling, the reaction solution was poured into a saturated aqueous ammonium chloride solution, extracted with ethyl acetate (500 mL, three times), the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a brown-red oil. The crude product was purified by silica gel chromatography (petroleum ether / ethyl acetate, 10 / 1) to obtain 52 g of a light yellow solid, namely intermediate M1, with a yield of 83%.

[0123] The synthesis method of intermediate M2 is different from that of M1 in that Replace with an equal amount of substance Obtain intermediate M2

[0124] Synthesis Example 1 Synthesis of Compound C4

[0125]

[0126] Synthesis of compound C4-1

[0127] Intermediate M1 (20.7 g, 50.3 mmol), 4-bromobiphenyl (11.7 g, 50.3 mmol) and sodium tert-butoxide (6.28 g, 65.4 mmol) were placed in a 250 mL three-necked flask, and then toluene (150 mL) was added. After sufficient stirring, the air in the flask was replaced by nitrogen, and then the catalyst [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (369 mg, 0.503 mmol) and 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (413 mg, 1.01 mmol) were added, and the temperature was raised to 100 °C for reaction for 16 h. After cooling to room temperature, the reaction solution was poured into a saturated aqueous ammonium chloride solution and extracted with ethyl acetate (100 mL, three times). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated to obtain a brown oil, which was purified by silica gel column chromatography (petroleum ether / dichloromethane, 15 / 1) to obtain 23 g of a light yellow solid, i.e., compound C4-1, with a yield of 80%.

[0128] Synthesis of compound C2

[0129] Compound C4-1 (15g, 26.8mmol), 2.4-diphenylbromobenzene (9.1g, 29.5mmol) and sodium tert-butoxide (3.4g, 34.9mmol) were placed in a 500mL three-necked flask containing 200mL toluene and stirred thoroughly to dissolve. Then the air in the flask was fully converted with nitrogen, and then the catalyst tri(dibenzylideneacetone)dipalladium (245mg, 0.268mmol) and 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (220mg, 0.536mmol) were added to the reaction solution, and the temperature was raised to reflux reaction for 18h. After cooling, the reaction solution was poured into a saturated aqueous ammonium chloride solution, extracted with ethyl acetate (200mL, three times), the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a brown-black oil. The crude product was purified by silica gel column (petroleum ether / dichloromethane, 15 / 1) to obtain a light yellow solid. The solid was recrystallized twice from toluene and methanol and then further purified by sublimation to obtain 10.0 g of a light yellow solid, namely compound C4.

[0130] The synthesis methods of Synthesis Examples 2 to 13 refer to Synthesis Example 1, and the corresponding raw materials used are summarized in Table 1.

[0131] Table 1

[0132]

[0133]

[0134] Example 1

[0135] This embodiment provides an organic electroluminescent device, and the specific preparation method is as follows:

[0136] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0137] Place the glass substrate with the anode in a vacuum chamber and evacuate the chamber to a vacuum of less than 1×10 -5 Pa, vacuum evaporating HT-4:HI-3 (97 / 3, w / w) on the above anode layer as a hole injection layer, the evaporation rate is 0.1 nm / s, and the evaporation film thickness is 10 nm;

[0138] A hole transport layer of the device is vacuum-deposited on the hole injection layer, the deposition rate is 0.1 nm / s, the total deposition film thickness is 60 nm, and the compound C4 of the present invention is selected as the hole transport layer material;

[0139] The electron blocking layer of the device is continuously vacuum-deposited on the hole transport layer, with a deposition rate of 0.1 nm / s and a total deposition thickness of 35 nm. Compound HT-14 is used as the electron blocking layer material;

[0140] The light-emitting layer of the device is vacuum evaporated on the electron blocking layer. The light-emitting layer includes a main material and a dye material. A multi-source co-evaporation method is used with an evaporation rate of 0.1 nm / s and an evaporation film thickness of 40 nm. A ternary mixture of compounds GPH-46:GPH-3:GPD-12 (100:100:20, w / w / w) is used as the light-emitting layer.

[0141] On the light-emitting layer, the electron transport layer material ET-46 of the device is vacuum-deposited at a ratio of 50% and ET-57 at a ratio of 50%, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 25 nm;

[0142] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0143] The difference between Examples 2 to 8 and Comparative Examples 1 to 2 and Example 1 is that the hole transport material (Compound C4) is replaced by other compounds, as shown in Table 2 for details.

[0144] The structure of the compound in the comparative example is as follows:

[0145] (See patent CN108774141A for details)

[0146] (See patent WO2015130069A for details)

[0147] Device testing method:

[0148] The organic electroluminescent device prepared by the above process was subjected to the following performance tests:

[0149] At the same brightness, the driving voltage and current efficiency of the organic electroluminescent devices prepared in Examples 1 to 8 and Comparative Examples 1 to 2, as well as the device life, were measured using a digital source meter and a brightness meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the brightness of the organic electroluminescent device was measured when it reached 10000 cd / m 2 The voltage at which the light is on is the driving voltage, and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency; the life test of LT97 is as follows: use a brightness meter at 10000cd / m 2 At the same brightness, the current is kept constant and the brightness of the organic electroluminescent device is measured to drop to 9700cd / m 2The test results are shown in Table 2.

[0150] Table 2

[0151]

[0152] It can be seen from the results in Table 2 that the use of the novel organic material of the present invention as a hole transport material for an organic electroluminescent device can effectively reduce the starting voltage of the device and improve the life of the device compared to the device prepared by using the comparative compounds R-1 and R-2 as the hole transport material.

[0153] Among them, the difference between compound R-2 and compound C90 is only that the ortho-position of the aromatic amine group replaces the carbazole group, and the device effect of comparative example 2 is significantly reduced compared with that of example 8;

[0154] The above experimental results prove that the present invention introduces a naphthalene ring structure at the para position of the aromatic amine and simultaneously introduces a condensed aromatic ring of a specific structure at the ortho position, and the substituents cooperate with each other. Only when used as a hole transport material can the technical effect of reducing the driving voltage and increasing the service life be achieved.

[0155] Example 9

[0156] The difference from Example 1 is that compound C4 is replaced by compound HT-21, and HT-14 is replaced by compound C1.

[0157] The difference between Examples 10 to 17 and Comparative Examples 3 to 4 and Example 9 is that the electron blocking material (Compound C1) is replaced by other compounds, as shown in Table 3 for details.

[0158] Table 3

[0159]

[0160] It can be seen from the results in Table 3 that the use of the novel organic material of the present invention as an electron blocking layer material for an organic electroluminescent device can also effectively reduce the starting voltage of the device and improve the life of the device compared to the device prepared by using the comparative compounds R-1 and R-2 as the electron blocking layer material.

[0161] Among them, when used as an electron blocking layer material, the effect of compound R-2 (Comparative Example 4) is still poor compared with compound C90 (Example 16);

[0162] The above experimental results prove that the present invention introduces a naphthalene ring structure at the para position of the aromatic amine and simultaneously introduces a condensed aromatic ring of a specific structure at the ortho position, and the substituents cooperate with each other. Only when used as electron blocks can the technical effect of reducing the driving voltage and increasing the service life be achieved.

[0163] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound, characterized in that The compound has a structure shown in Formula I; In Formula I, X is CR 4 R 5 ; The R 4 and R 5 Each independently selected from one of C1 to C6 chain alkyl groups; The R 4 and R 5 Not connected into a ring; In Formula I, the L 1 and L 2 Each is independently selected from a single bond, a substituted or unsubstituted C6-C12 arylene group; In Formula I, Ar 1 and Ar 2 Each is independently selected from a substituted or unsubstituted C6-C12 aryl group, a substituted or unsubstituted C3-C20 heteroaryl group, or a substituted or unsubstituted one of the following groups: anthracenyl, benzanthryl, triphenylenyl, pyrenyl, fluoranthenyl, naphthylene, pentacene, benzopyrenyl, terphenyl, quaterphenyl, fluorenyl, benzofluorenyl, indolofluorenyl, spirobifluorenyl, dihydrophenanthrenyl, dihydropyrenyl, tetrahydropyrenyl, cis-indenofluorenyl, trans-indenofluorenyl; In Formula I, the R 1 , R 2 and R 3 Each is independently selected from a substituted or unsubstituted C1-C18 chain alkyl group, a substituted or unsubstituted C3-C18 cycloalkyl group, a substituted or unsubstituted C1-C18 alkoxy group, a halogen, a cyano group, a nitro group, a hydroxyl group, a C1-C18 silane group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group; In formula I, a, m and n are all 0; When the above-mentioned groups have substituents, the substituents are selected from one or a combination of at least two of halogen, C1-C10 chain alkyl, C3-C10 cycloalkyl, C1-C6 alkoxy, C1-C6 thioalkoxy, C6-C12 monocyclic aromatic group, C10-C12 condensed aromatic group, C3-C20 monocyclic heteroaryl group, C6-C20 condensed heteroaryl group.

2. The compound according to claim 1, characterized in that The compound has a structure shown in formula (2-1) or formula (2-2); X, L 1 , L 2 ,Ar 1 ,Ar 2 , R 1 , R 2 , R 3 , a, m and n all have the same defined ranges as claim 1.

3. The compound according to claim 1, characterized in that The compound has a structure shown in formula (3-1) or formula (3-2); X, L 1 , L 2 ,Ar 1 and Ar 2 All have the same definition as claim 1.

4. The compound according to claim 1, characterized in that The R 4 and R 5 All are methyl.

5. The compound according to claim 1, characterized in that The Ar 1 and Ar 2 Each is independently selected from the following substituted or unsubstituted groups: phenyl, naphthyl, anthracenyl, benzanthryl, triphenylenyl, pyrenyl, fluoranthenyl, tetraphenyl, pentacene, benzopyrenyl, biphenyl, terphenyl, quaterphenyl, fluorenyl, benzofluorenyl, indolofluorenyl, spirobifluorenyl, dihydrophenanthrenyl, dihydropyrenyl, tetrahydropyrenyl, cis-indenofluorenyl, trans- indenofluorenyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzodibenzofuranyl, fluorenylbenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, benzodibenzothienyl, fluorenylbenzothienyl, acridinyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, phenothiazinyl or phenoxazinyl; When the above-mentioned groups have substituents, the substituents are selected from one or a combination of at least two of halogen, C1-C10 chain alkyl, C3-C10 cycloalkyl, C1-C6 alkoxy, C1-C6 thioalkoxy, C6-C12 monocyclic aromatic group, C10-C12 condensed aromatic group, C3-C20 monocyclic heteroaryl group, C6-C20 condensed heteroaryl group.

6. The compound according to claim 1, characterized in that The L 1 and L 2 Each is independently selected from a single bond or a phenylene group.

7. A compound, characterized in that The compound has any one of the structures shown in the following C1-C89, D1-D85, E1-E89 and F1-F85:

8. Use of a compound according to any one of claims 1 to 7, characterized in that: The compound is used as a hole transport material or an electron blocking material for an organic electroluminescent device.

9. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a substrate, a first electrode, a second electrode and at least one organic layer between the first electrode and the second electrode; the organic layer comprises a hole transport layer, and the hole transport layer comprises at least one compound according to any one of claims 1 to 7; Alternatively, the organic layer comprises an electron blocking layer, and the electron blocking layer comprises at least one compound according to any one of claims 1 to 7.

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