An acridine fused ring derivative and use thereof

Abstract

A compound having the structure shown in formula (I): R1-R5 are each independently a halogen, cyano, -L-NAr1Ar2, substituted or unsubstituted C1-C20 alkyl, C3-C20 cycloalkyl, C6-C30 aryl, or C3-C30 heteroaryl, and at least one of R1 to R5 is -L-NAr1Ar; R6 and R7 are each independently a substituted or unsubstituted C1-C20 alkyl, C3-C20 cycloalkyl, C6-C30 aryl, or C3-C30 heteroaryl, and R6 and R7 are optionally linked to form a ring; L is a single bond, a substituted or unsubstituted C6-C30 arylene, or... C3-C30 heteroaryl groups; Ar1 ​​and Ar2 are each independently substituted or unsubstituted C1-C20 alkyl, C3-C20 cycloalkyl, C6-C30 aryl, or C3-C30 heteroaryl groups; when the above substituted or unsubstituted groups have substituents, the substituents are selected from halogens, cyano, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C20 aryl, or C3-C20 heteroaryl groups; m, o, n, q, and p are the number of R1 to R5, each independently ranging from 0 to the maximum allowed integer, and the number of substituents of -L-NAr1Ar2 among R1 to R5 is not 0.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and more particularly to a compound and its applications. Background Technology

[0002] In recent years, optoelectronic devices based on organic materials have developed rapidly, becoming a research hotspot in the field. Examples of such organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic field-effect transistors, organic photovoltaic cells, and organic sensors. Among them, OLEDs have developed particularly rapidly and have already achieved commercial success in the field of information display. OLEDs can provide highly saturated red, green, and blue colors, and full-color display devices made with them do not require an additional backlight, offering advantages such as vibrant colors, thinness, and flexibility.

[0003] The core of an OLED device is a multilayer thin-film structure containing various organic functional materials. Common functionalized organic materials include: hole injection materials, hole transport materials, hole blocking materials, electron injection materials, electron transport materials, electron blocking materials, as well as light-emitting host materials and light-emitting guest materials (dyes). When an electric current is applied, electrons and holes are injected and transported to the light-emitting region, where they recombine, thereby generating excitons and emitting light.

[0004] Common phosphors primarily utilize singlet excitons generated when electrons and holes combine to emit light, and are still widely used in various OLED products. Some metal complexes, such as iridium complexes, can simultaneously utilize both triplet and singlet excitons to emit light; these are called phosphors, and their energy conversion efficiency can be up to four times higher than that of traditional phosphors. Thermally excited delayed fluorescence (TADF) technology promotes the conversion of triplet excitons to singlet excitons, achieving high luminous efficiency without the use of metal complexes, while still effectively utilizing triplet excitons. Thermally excited sensitized fluorescence (TASF) technology uses materials with TADF properties to sensitize the phosphor through energy transfer, also achieving high luminous efficiency.

[0005] Hole transport materials significantly affect the voltage of devices and also regulate the carrier transport balance within the device. Improving the carrier mobility of hole transport materials can enhance luminous efficiency and delay device degradation. Although products using OLED display technology are already commercialized, continuous improvements in device lifespan, efficiency, and other performance aspects are still needed to meet people's demands for higher quality. Summary of the Invention

[0006] The problem the invention aims to solve

[0007] There is an urgent need in this field to develop more types of organic materials for use in organic electroluminescent devices, so that the devices can have higher luminous efficiency, lower driving voltage and longer lifespan.

[0008] In view of the above needs, one of the objectives of the present invention is to provide a compound, and more particularly to provide a hole transport material, which, when applied in OLED devices, can improve luminous efficiency and lifespan, and reduce driving voltage.

[0009] Solution to the problem

[0010] Through dedicated research, the inventors discovered that by introducing an aromatic amine group at a specific position in the core structure obtained by fusion of an indole-acridine group and a fluorene group, the resulting compound can improve the luminous efficiency and lifespan of organic electroluminescent devices using the compound, while reducing the driving voltage, thus completing this invention.

[0011] Specifically, this invention proposes a fused-ring derivative whose core contains an acridine group, having the structure shown in formula (I):

[0012]

[0013] R1-R5 are each independently a halogen, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, or -L-NAr1Ar2, and at least one of R1 to R5 is -L-NAr1Ar2;

[0014] R6 and R7 are each independently a substituted or unsubstituted C1-C20 alkyl, a substituted or unsubstituted C3-C20 cycloalkyl, a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl, and R6 and R7 are optionally linked into a ring.

[0015] L is a single bond, a substituted or unsubstituted C6-C30 arylene, or a substituted or unsubstituted C3-C30 heteroarylene;

[0016] Ar1 and Ar2 are each independently a substituted or unsubstituted C1-C20 alkyl, a substituted or unsubstituted C3-C20 cycloalkyl, a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl.

[0017] When the above-mentioned substituted or unsubstituted groups have substituents, each substituent is independently selected from halogen, cyano, C1-10 alkyl, C3-C10 cycloalkyl, C6-C20 aryl, and C3-C20 heteroaryl.

[0018] m, o, n, q, and p are the number of substituents R1 to R5, each independently ranging from 0 to the largest allowed integer, and the number of substituents of -L-NAr1Ar2 among R1 to R5 is not 0; H in formula (I) is a hydrogen atom.

[0019] The compounds of this invention can improve the luminous efficiency and lifespan of organic electroluminescent devices using these compounds. While the exact mechanism by which they reduce the driving voltage is not fully understood, it is hypothesized as follows: This invention employs a core structure (general formulas I and II) obtained by fusion of an indole-acridine group and a fluorene group. This core structure exhibits high planarity, effectively enhancing carrier transport performance. Furthermore, the large spatial angle between the plane of the fluorene group and the plane of the indole-acridine group, along with the presence of two substituents at the 9-position of the acridine, increases steric hindrance, preventing excessively dense material packing and crystallization. In addition, the N atom in the core is located at the center of the plane, enhancing the bond energy balance of the indole-acridine structure and improving material stability. The indole-acridine-like structures contained in the characteristic groups of this invention possess electron-donating properties, effectively enhancing the HOMO energy level of the material. The connection of specific aromatic amine groups in OLED devices facilitates hole injection, reducing the driving voltage. When located at the interfaces between layers of an OLED device, the compounds of this invention can effectively prevent the formation of interlayer excitocomplexes, which is beneficial to the device's efficiency and lifespan. The positions of the fluorene group in the parent core of this invention are indicated by numbers 1-8. The inventors have discovered that the presence of a substituent (i.e., not hydrogen) at position 1 of the fluorene group in the parent core is detrimental to achieving the technical effects of this invention. The underlying principle is not yet clear, but it is speculated that this position is closest to the indole-acridine group; if a substituent is present, it may affect the conformation of the indole-acridine group, for example, weakening its contribution to the HOMO energy level.

[0020] In this specification, the expression Ca to Cb represents that the group has a to b carbon atoms. Unless otherwise specified, the number of carbon atoms generally does not include the number of carbon atoms of the substituents.

[0021] In this specification, the way a ring structure is represented by "—" indicates that the connection site is any position on the ring structure where bonding can occur.

[0022] In this specification, "each independently" means that when there are multiple subjects, they may be the same or different from each other.

[0023] In this invention, unless otherwise specified, the description of chemical elements generally includes the concept of their isotopes. For example, the description of "hydrogen (H)" includes its isotopes. 1 H (protium or H), 2The concept of H (deuterium or D); carbon (C) includes... 12 C 13 C, etc., will not be elaborated further.

[0024] In this specification, heteroatoms generally refer to atoms or groups of atoms selected from N, O, S, P, Si and Se, preferably selected from N, O and S.

[0025] Examples of halogens in this specification include fluorine, chlorine, bromine, and iodine.

[0026] The aforementioned C1 to C20 alkyl groups, preferably C1 to C10 alkyl groups, include, for example, methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-pentyl, n-heptyl, n-nonyl, n-decyl, etc.

[0027] The aforementioned C3-C20 cycloalkyl group is preferably a C3-C10 cycloalkyl group, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, etc.

[0028] In this specification, C6-C30 aryl groups include monocyclic aryl and fused-ring aryl groups. Monocyclic aryl refers to an aromatic ring existing as a single ring without fusion, including but not limited to phenyl, biphenyl, or terphenyl. Fused-ring aryl refers to a structure with at least two aromatic rings fused together, including but not limited to naphthyl, anthracene, phenanthryl, fluorene, etc.

[0029] In this specification, C3-C30 heteroaryl groups include monocyclic heteroaryl groups and fused-ring heteroaryl groups. Monocyclic heteroaryl groups refer to heteroaryl groups where the heterocyclic ring exists as a single ring without fusion, including but not limited to furan, thiophene, pyridine, pyrimidine, triazine, or groups formed by the linkage of at least two of these. Fused-ring heteroaryl groups refer to fused-ring aryl groups containing heteroatoms, including but not limited to dibenzofuran groups, dibenzothiophene groups, or carbazole groups.

[0030] In this invention, unless otherwise specified, the substituents do not fuse with the group they belong to. This is because the structure obtained after fusion is actually a conjugated system different from the original parent nucleus. Therefore, without verification, it should not be assumed that the fused system can achieve the technical effects of this invention.

[0031] Specific examples of aryl groups in this invention can be exemplified by removing one hydrogen atom from the aforementioned aryl examples to obtain a divalent group. Specific examples of heteroaryl groups in this invention can be exemplified by removing one hydrogen atom from the aforementioned heteroaryl examples to obtain a divalent group.

[0032] The compounds of the present invention preferably have the structure shown in formula (II):

[0033]

[0034] In the compounds of this invention, Ar1 and Ar2 are each independently a substituted or unsubstituted C1-C20 alkyl, a substituted or unsubstituted C3-C20 cycloalkyl, a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl. As mentioned above, unless otherwise specified, the number of carbon atoms in this invention generally does not include the number of carbon atoms of the substituents, and this is also true here. However, the inventors have found that when the substituents (Ar1 and Ar2) attached to the aromatic amine group of the parent nucleus have an excessively large group volume, it has a negative impact on the technical effect of this invention. The group volume can be approximately determined by the total number of carbon atoms. Of course, different similar groups have different upper limits for the number of carbon atoms that do not negatively affect the technical effect of this invention. For example, aromatic groups (including aryl and heteroaryl) have less steric hindrance than alkyl groups when the total number of carbon atoms is the same, because the aromatic part is planar or nearly planar. Therefore, the upper limit for the total number of carbon atoms is higher than that of alkyl groups. Therefore, in this invention, Ar1 and Ar2 are preferably each independently a substituted or unsubstituted alkyl group with a total carbon number of C1-C20, a substituted or unsubstituted cycloalkyl group with a total carbon number of C3-C20, a substituted or unsubstituted aryl group with a total carbon number of C6-C30, or a substituted or unsubstituted heteroaryl group with a total carbon number of C3-C30. More preferably, they are each independently a substituted or unsubstituted alkyl group with a total carbon number of C1-12, a substituted or unsubstituted cycloalkyl group with a total carbon number of C3-C12, a substituted or unsubstituted aryl group with a total carbon number of C6-C20, or a substituted or unsubstituted heteroaryl group with a total carbon number of C3-C20 (i.e., in this preferred embodiment, the number of carbon atoms includes the number of carbon atoms in the substituents). Furthermore, from a practical application perspective, an excessively large molecular weight can lead to more problems with Tg and vapor deposition temperature, resulting in poor practical performance.

[0035] Ar1 and Ar2 are more preferably each independently composed of propyl, cyclohexyl, phenyl, tolyl, tert-pentylphenyl, isopropylphenyl, tert-butylphenyl, dimethylpropylphenyl, biphenyl, naphthyl, phenanthryl, dimethylfluorenyl, benzodimethylfluorenyl, benzodibenzothiophene, benzodibenzofuranyl, terphenyl, tert-butylbiphenyl, cyclopentylfluorenyl, trifluoromethylphenyl, tetraphenyl, dipyrimidinylphenyl, phenylcyano, naphthiocyano, triphenylene, tert-butylnaphthyl; Ar1 ​​and Ar2 are most preferably each independently composed of phenyl, isopropylphenyl, tert-butylphenyl, dimethylpropylphenyl, biphenyl, naphthyl, dimethylfluorenyl.

[0036] By setting Ar1 and Ar2 as the aforementioned groups, the driving voltage of organic electroluminescent devices using this compound can be further reduced.

[0037] In the compounds of the present invention, R6 and R7 are preferably each independently a substituted or unsubstituted C1-C10 alkyl, a substituted or unsubstituted C3-C10 cycloalkyl, a substituted or unsubstituted C6-C20 aryl, or a substituted or unsubstituted C3-C20 heteroaryl, and R6 and R7 are optionally linked into a ring.

[0038] More preferably, R6 and R7 are each independently substituted or unsubstituted C1-C10 alkyl groups, and R6 and R7 are optionally linked into a ring;

[0039] Further preferably, R6 and R7 are each independently methyl or phenyl;

[0040] The optimal choice is that both R6 and R7 are methyl groups.

[0041] By setting R6 and R7 as the aforementioned groups, the lifespan of organic electroluminescent devices using this compound can be improved.

[0042] In the compounds of the present invention, L is preferably a single bond, a substituted or unsubstituted C6-C20 arylene, or a substituted or unsubstituted C3-C20 heteroarylene;

[0043] More preferably, L is a single bond, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted pyridylene group;

[0044] Further preferred form of L is a single bond, a phenylene group, or a pyridylene group;

[0045] The optimal choice is for L to be a single bond or a phenylene oxide.

[0046] In the compounds of the present invention, preferably R1-R5 are each independently a halogen, a cyano, a substituted or unsubstituted C1-C10 alkyl, a substituted or unsubstituted C3-C10 cycloalkyl, a substituted or unsubstituted C6-C20 aryl, a substituted or unsubstituted C3-C20 heteroaryl, or -L-NAr1Ar2, and at least one of R1 to R5 is -L-NAr1Ar2;

[0047] More preferably, each of R1-R5 is independently a halogen, cyano, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C20 aryl, C3-C20 heteroaryl, or -L-NAr1Ar2, and at least one of R1 to R5 is -L-NAr1Ar2.

[0048] Further preferably, R1-R5 are each independently methyl, phenyl, pyridyl, or -L-NAr1Ar2, and at least one of R1 to R5 is -L-NAr1Ar2.

[0049] In the compounds of the present invention, preferably only one of R1 to R5 is -L-NAr1Ar2, and all of m, o, n, q, and p are 0 except for the substituents in R1 to R5 that are -L-NAr1Ar2.

[0050] In this invention, the compound represented by formula (I) is preferably selected from one of the following structures:

[0051]

[0052] In this invention, the compound represented by formula (II) is preferably selected from one of the following structures:

[0053]

[0054] That is, preferably, only one of R1 to R5 is -L-NAr1Ar2, and among m, o, n, q, and p, the one corresponding to the substituent of R1 to R5 that is -L-NAr1Ar2 is 1.

[0055] By configuring it as one of the structures described above, the luminous efficiency of organic electroluminescent devices using this compound can be improved.

[0056] The compounds of the present invention preferably have any one of the following structures:

[0057]

[0058]

[0059]

[0060]

[0061] The object of this invention is to provide an application of the compound described in one of the objects, wherein the compound is used in an organic electroluminescent device.

[0062] The present invention aims to provide an organic electroluminescent device, the organic electroluminescent device comprising a first electrode, a second electrode, and at least one organic layer inserted between the first electrode and the second electrode, the organic layer containing at least one compound described in one of the objectives.

[0063] Preferably, the organic layer includes a hole transport layer containing at least one of the compounds described in one of the objectives.

[0064] Invention Effects

[0065] According to the present invention, a compound can be provided that, when applied to an OLED device, can improve luminous efficiency and lifespan while reducing driving voltage.

[0066] The compounds of this invention can be applied not only to organic electroluminescent devices, but also to other types of organic electronic devices, including organic field-effect transistors, organic thin-film solar cells, information tags, electronic artificial skin sheets, sheet-type scanners, or electronic paper. Detailed Implementation

[0067] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0068] Specifically, another technical solution of the present invention provides an organic electroluminescent device, including a substrate, and an anode layer, a plurality of light-emitting functional layers and a cathode layer sequentially formed on the substrate; the light-emitting functional layers include at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron blocking layer and an electron transport layer, wherein the hole transport layer contains at least one of the above-mentioned compounds.

[0069] An OLED includes a first electrode and a second electrode, and an organic material layer located between the electrodes. This organic material layer can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region.

[0070] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0071] The first electrode can be formed by sputtering or depositing the material to be used as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), ytterbium (Yb), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof.

[0072] Organic material layers can be formed on electrodes using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as organic material layers can be small organic molecules, large organic molecules, polymers, and combinations thereof.

[0073] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. Alternatively, the hole transport region can be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL), wherein the hole transport layer uses the compound represented by Formula I of this invention.

[0074] The material for the hole transport region may be selected from, but is 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, wherein the aromatic amine derivatives include compounds shown below HT-1 to HT-51; or any combination thereof.

[0075]

[0076]

[0077]

[0078] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be one or more compounds of HT-1 to HT-51 described above, or one or more compounds of HI-1 to HI-3 described below; it can also be one or more compounds of HT-1 to HT-51 doped with one or more compounds of HI-1 to HI-3 described below.

[0079]

[0080] The emissive layer includes luminescent dyes (i.e., dopants) that can emit different wavelengths of light, and may also include a host material. The emissive layer can be a monochromatic emissive layer emitting a single color such as red, green, or blue. Multiple monochromatic emissive layers of different colors can be arranged in a planar pattern according to pixel design, or they can be stacked together to form a colored emissive layer. When different colored emissive layers are stacked together, they can be separated from each other or connected to each other. The emissive layer can also be a single colored emissive layer that can simultaneously emit different colors such as red, green, and blue.

[0081] Depending on the technology used, the light-emitting layer material can be various, including fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescence materials. An OLED device can employ a single light-emitting technology or a combination of different technologies. These different light-emitting materials, categorized by technology, can emit light of the same color or different colors.

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

[0083]

[0084]

[0085] In one aspect of the invention, the light-emitting layer employs fluorescent electroluminescence technology. The fluorescent dopant of the light-emitting layer may be selected from, but is not limited to, one or more combinations of BFD-1 to BFD-24 listed below.

[0086]

[0087]

[0088] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of pH-1 to pH-85.

[0089]

[0090]

[0091]

[0092]

[0093] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The phosphorescent dopant of the light-emitting layer may be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0094]

[0095]

[0096]

[0097] Where D stands for deuterium.

[0098] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The phosphorescent dopant of the light-emitting layer may be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0099]

[0100]

[0101] In one aspect of the invention, the light-emitting layer employs phosphorescent photoluminescence technology. The phosphorescent dopant of the light-emitting layer may be selected from, but not limited to, one or more combinations of YPD-1 to YPD-11 listed below.

[0102]

[0103] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0104] In one aspect of the present invention, the electron transport layer material may be selected from, but not limited to, one or more combinations of ET-1 to ET-73 listed below.

[0105]

[0106]

[0107]

[0108]

[0109] 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, Yb, Li or Ca.

[0110] The preferred compounds of this invention can be obtained through common coupling reactions between different halogenated aromatic hydrocarbons and aromatic amines, with representative synthetic routes as follows:

[0111]

[0112] Synthesis example

[0113] Synthesis of compound C1

[0114]

[0115] Acridine (14 g), o-fluorobromobenzene (12 g), and cesium carbonate (40 g) were dissolved in DMF (150 ml), and the mixture was heated to 140 °C overnight under nitrogen protection. After the reaction was complete, an appropriate amount of water was added, and the mixture was extracted with ethyl acetate, concentrated, and then purified by silica gel column chromatography to obtain a white solid C1-M1 (18 g).

[0116] Under nitrogen protection, C1-M1 (18g) was dissolved in THF and cooled to -78℃. 6mL of n-BuLi was added dropwise. Half an hour after the addition was complete, 11.7g of 3-chloro-9-fluorenone was added, and the mixture was allowed to react overnight at room temperature. The reaction was quenched with water, the reaction solution was extracted with ethyl acetate, concentrated, and purified by silica gel column chromatography to obtain a yellowish-white solid, C1-M2 (21g).

[0117] Under nitrogen protection, C1-M2 (21g) and methanesulfonic acid (8g) were dissolved in DCM and stirred at room temperature for 4 hours. The reaction was stopped, the solvent was concentrated, and the solution was purified by column chromatography to obtain a white solid, C1-M3 (25g).

[0118] In a 500 mL single-necked flask, C1-M3 (25 g), aniline (5.4 g), sodium tert-butoxide (16 g), tris(dibenzylacetone)dipalladium (0.8 g), and IPr·HCl (0.45 g) were added, along with 250 mL of toluene. The mixture was evacuated under vacuum and purged with nitrogen three times. The reaction was then heated to 90 °C and allowed to proceed overnight. After the reaction was complete, it was stopped. The mixture was cooled to room temperature, and the reaction solution was separated. The organic phase was concentrated, and methanol was added and stirred for 1 h. The mixture was then filtered to obtain a pale yellow powder, C1-M4 (26 g).

[0119] C1-M4 (26 g), bromobenzene (11 g), sodium tert-butoxide (9 g), and tris(dibenzylacetone)dipalladium (0.9 g) were added to 500 ml of toluene. The mixture was then purged with nitrogen three times under vacuum. Tri-tert-butylphosphine ((tert-Bu)3P, 1 mol / L, 2 ml) was added, and the mixture was heated to reflux and reacted overnight. After the reaction was complete, heating was stopped, and the mixture was filtered through diatomaceous earth while hot. The solvent in the filtrate was concentrated. The residue was purified by silica gel column chromatography, and the crude product was washed with ethyl acetate to obtain a white solid, C1 (18 g). Theoretical M / Z value: 614.3; Measured value on ZAB-HS mass spectrometer (Micromass, UK): 615.3 (M+1).

[0120] Synthesis of compound C13

[0121]

[0122] Acridine (20 g), 2-fluoro-4-chloro-bromobenzene (15 g), and cesium carbonate (20 g) were dissolved in DMF (200 ml) and heated to 140 °C overnight under nitrogen protection. After the reaction was complete, an appropriate amount of water was added, and the mixture was extracted with ethyl acetate, concentrated, and then purified by silica gel column chromatography to obtain a white solid C13-M1 (23 g).

[0123] Under nitrogen protection, C13-M1 (23g) was dissolved in THF and cooled to -78℃. 8mL of n-BuLi was added dropwise. Half an hour after the addition was complete, 12.5g of 9-fluorenone was added, and the mixture was allowed to react overnight at room temperature. The reaction was quenched with water, and the reaction solution was extracted with ethyl acetate. After concentration, the solution was purified by silica gel column chromatography to obtain a pale yellow solid, C13-M2 (29g).

[0124] Under nitrogen protection, C13-M2 (29g) and methanesulfonic acid (10g) were dissolved in DCM and stirred at room temperature for 5 hours. The reaction was stopped, the solvent was concentrated, and ethanol was added to slurry and wash to precipitate a yellowish-white solid as C13-M3 (33g).

[0125] In a 500 mL single-necked flask, C13-M3 (33 g), aniline (6.4 g), sodium tert-butoxide (19 g), tris(dibenzylacetone)dipalladium (0.9 g), and IPr·HCl (0.5 g) were added, along with 250 mL of toluene. The mixture was evacuated under vacuum and purged with nitrogen three times. The reaction was then heated to 90 °C and reacted for 5 h. After the reaction was complete, it was stopped. The mixture was cooled to room temperature, and the reaction solution was separated. The organic phase was concentrated, and methanol was added and stirred for 1 h. The mixture was then filtered to obtain a pale yellow powder, C13-M4 (30 g).

[0126] C13-M4 (30 g), 2-bromo-dimethylfluorene (15 g), sodium tert-butoxide (10 g), and tris(dibenzylacetone)dipalladium (1 g) were added to 500 ml of toluene. The mixture was then purged with nitrogen three times under vacuum. Tri-tert-butylphosphine ((tert-Bu)3P, 1 mol / L, 2 ml) was added, and the mixture was heated to reflux and reacted for 8 hours. After the reaction was complete, heating was stopped, and the mixture was filtered through diatomaceous earth while hot. The solvent in the filtrate was concentrated. The residue was purified by silica gel column chromatography, and the crude product was washed with ethyl acetate to obtain a white solid, C13 (25 g).

[0127] Theoretical M / Z value: 730.3; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 731.3 (M+1).

[0128] Synthesis of compound C14

[0129]

[0130] The synthesis of C14 follows a similar method to that used for C13, except that 2-bromo-dimethylfluorene is replaced with 4-bromo-tert-butylbenzene to obtain C14.

[0131] Theoretical M / Z value: 670.3; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 671.3 (M+1).

[0132] Synthesis of compound C15

[0133]

[0134] The synthesis of C15 follows a similar method to that used for C13, except that 2-fluoro-4-chloro-bromobenzene is replaced with 2-fluoro-5-chloro-bromobenzene, and 2-bromo-dimethylfluorene is replaced with 4-bromotert-pentylbenzene, thus yielding C15.

[0135] Theoretical M / Z value: 684.3; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 685.3 (M+1).

[0136] Synthesis of compound C20

[0137]

[0138] C20-M3 (14g) was synthesized using the same method as C13-M3.

[0139] In a 250 mL single-necked flask, add C20-M3 (14 g), 4-aminophenylboronic acid (4.4 g), potassium carbonate (12 g), tris(dibenzylacetone)dipalladium (0.5 g), and Sphos (0.5 g), along with 150 mL of toluene and 20 mL of water. The mixture is evacuated under vacuum and purged with nitrogen three times. The reaction mixture is then heated to 110 °C and reacted overnight. After the reaction is complete, it is stopped. The mixture is cooled to room temperature, separated, and the organic phase is concentrated. Column chromatography yields a pale yellow powder, C20-M4 (16 g).

[0140] The final step is similar to the synthesis of C13 to synthesize C20, except that 2-bromo-dimethylfluorene is replaced with bromobenzene to obtain C20.

[0141] Theoretical M / Z value: 690.3; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 691.3 (M+1).

[0142] Synthesis of compound C29

[0143]

[0144] The synthesis of C29-M3 was performed using a method similar to that used for C1-M3, except that the starting material acridine was replaced with 2-methoxyacridine to prepare C29-M3 (15g).

[0145] At 0°C, C29-M3 (15g) was dissolved in 150mL of DCM, and then BBr3 (14.6g) was added dropwise. The reaction was allowed to proceed for 2 hours after the addition was complete. The reaction was quenched with water, and the organic phase was collected by separation and dried with anhydrous sodium sulfate. The mixture was then stirred at 0°C, and trifluoromethanesulfonic anhydride (10g) was added dropwise. The reaction was allowed to proceed overnight after the addition was complete. After quenching the reaction with water, the organic phase was collected by separation, concentrated, and dried to obtain a white solid C29-M4 (17g).

[0146] The last two steps are similar to the synthesis of C1-M4 and C1, synthesizing C29-M6 and C29, except that aniline is replaced with p-tert-butylaniline and bromobenzene is replaced with 3-bromodimethylfluorene to obtain C29.

[0147] Theoretical M / Z value: 786.4; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 787.4 (M+1).

[0148] Synthesis of compound C42

[0149]

[0150] The synthesis of C42 follows a similar method to that used for C13, except that the starting material acridine is replaced with 2-chloroacridine and aniline is replaced with 1-naphthylamine, thus yielding C42.

[0151] Theoretical M / Z value: 780.3; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 781.3 (M+1).

[0152] Synthesis of compound C55

[0153]

[0154] The synthesis of C55 followed a similar method to that of C1, except that 3-chloro-9-fluorenone was replaced with 4-chloro-9-fluorenone, aniline with 2-naphthylamine, and bromobenzene with 4-bromobiphenyl, yielding C55. Theoretical M / Z value: 740.3; Measured value using a ZAB-HS mass spectrometer (manufactured by Micromass, UK): 741.3 (M+1).

[0155] Synthesis of compound C71

[0156]

[0157] The synthesis of C71 follows a similar method to that used for C29, except that o-fluorobromobenzene is replaced with 3-fluoro-4-bromobiphenyl and tert-butylaniline is replaced with isopropylaniline, thus yielding C71.

[0158] Theoretical M / Z value: 848.4; Actual value measured by ZAB-HS mass spectrometer (manufactured by Micromass, UK): 849.4 (M+1).

[0159] Example 1

[0160] This embodiment provides an organic electroluminescent device, and the specific fabrication process is as follows:

[0161] The glass plate coated with an ITO transparent conductive layer (as the anode) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone:ethanol mixed solvent, baked in a clean environment until all moisture was removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0162] The glass substrate with the anode was placed in a vacuum chamber and evacuated to a vacuum level of less than 1 × 10⁻⁶. -5 Pa, a 10 nm HTL-4:HI-3 (97 / 3, w / w) mixture was vacuum thermally deposited on the above anodic film in sequence as a hole injection layer;

[0163] The 60nm compound HT-4 is used as the first hole transport layer;

[0164] Compound C1 with a 5nm diameter was used as the second hole transport layer;

[0165] A 40nm PH-34:RPD-10 (100:3, w / w) binary mixture was used as the emitting layer; a 5nm ET-23 was used as the hole blocking layer; a 25nm ET-69:ET-57 (50 / 50, w / w) mixture was used as the electron transport layer; a 1nm LiF was used as the electron injection layer; and a 150nm aluminum electrode was used as the cathode. The total evaporation rate of all organic layers and LiF was controlled at 0.1nm / s, and the evaporation rate of the metal electrode was controlled at 1nm / s.

[0166] The fabrication process of the organic electroluminescent devices provided in Examples 2-9 and Comparative Examples 1-4 is the same as that in Example 1, except that the second hole transport layer material compound C1 is replaced with the compounds shown in Table 1.

[0167] The structures of the second hole transport layer materials in Comparative Examples 1-4 are shown below:

[0168]

[0169] Performance testing

[0170] The organic electroluminescent devices prepared by the above process were subjected to the following performance measurements:

[0171] Under the same brightness, the driving voltage and current efficiency of the organic electroluminescent devices prepared in the examples and comparative examples were measured. Specifically, the voltage and efficiency were at 3000 cd / m². 2 The measured value was 60 mA / cm, and the lifetime (LT97) was 60 mA / cm. 2 The time it takes for the brightness to decay to 97% of its initial brightness under constant current. The obtained data are summarized in Table 1 below.

[0172] Table 1

[0173]

[0174]

[0175] As can be seen from the data in the table, the novel organic material provided by this invention can produce superior performance through the combination of specific substituents. When used in organic electroluminescent devices, it can effectively improve current efficiency, reduce driving voltage, and extend device life, making it a high-performance secondary hole transport material.

[0176] This invention illustrates the compounds of the present invention and their application in OLED devices through the above embodiments. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials 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, It has the structure shown in equation (II): Equation (II) R1-R5 are each independently methyl, phenyl, pyridyl, or -L-NAr1Ar2, and there is only one of R1 to R5 that is -L-NAr1Ar2; R6 and R7 are each independently methyl or phenyl; L is a single bond, a phenylene group, or a pyridylene group; Ar1 and Ar2 are each independently propyl, cyclohexyl, phenyl, tolyl, tert-pentylphenyl, isopropylphenyl, tert-butylphenyl, dimethylpropylphenyl, biphenyl, naphthyl, phenanthryl, dimethylfluorenyl, benzodimethylfluorenyl, benzodibenzothiophene, benzodibenzofuranyl, terphenyl, tert-butylbiphenyl, cyclopentylfluorenyl, trifluoromethylphenyl, tetraphenyl, dipyrimidinylphenyl, phenylcyano, naphthylcyano, triphenylene, tert-butylnaphthyl, dibenzofuranyl, dibenzothiophene; m, o, n, q, and p are the number of substituents R1 to R5, each independently ranging from 0 to the largest allowed integer; H in formula (II) is a hydrogen atom.

2. The compound according to claim 1, characterized in that, Ar1 and Ar2 are each independently phenyl, isopropylphenyl, tert-butylphenyl, dimethylpropylphenyl, biphenyl, naphthyl, or dimethylfluorenyl.

3. The compound according to claim 1, characterized in that, Both R6 and R7 are methyl groups.

4. The compound according to claim 1, characterized in that, L represents a single bond or a phenylene oxide.

5. The compound according to claim 1, characterized in that, Except for the -L-NAr1Ar2 substituents in R1 to R5, all other values ​​of m, o, n, q, and p are 0.

6. Compounds having the following structure: 。 7. The use of the compound according to any one of claims 1 to 6 in organic electroluminescent devices.

8. An organic electroluminescent device, comprising a first electrode, a second electrode, and at least one organic layer inserted between the first electrode and the second electrode, wherein the organic layer contains at least one compound according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8, wherein the organic layer comprises a hole transport layer, and the hole transport layer contains at least one compound according to any one of claims 1 to 6.

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