A boron-containing heterocyclic compound and its application

Abstract

The present invention provides a boron-containing heterocyclic compound, an organic electroluminescent element, and an organic electroluminescent material. The boron-containing heterocyclic compound has a structural formula as shown in Formula I. Compared with the prior art, the present invention utilizes a compound with a seven-membered boron-nitrogen unit as the parent nucleus as the luminescent unit. This utilizes the resonance effect between the boron and nitrogen atoms to separate the HOMO and LUMO, thereby achieving the TADF effect. The large, planar fused ring unit reduces the degree of structural relaxation in the excited state, thereby achieving a narrower half-width. Furthermore, by introducing different substituents onto the rigid backbone, the delayed fluorescence lifetime and half-width can be further adjusted.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroluminescence, and in particular relates to a boron-containing heterocyclic compound, an organic electroluminescent material and an organic electroluminescent element. Background Art

[0002] Due to the limitations of spin quantum statistics, traditional fluorescent materials can only utilize singlet excitons, which account for 25% of the total number of excitons, during the electroluminescence process. The remaining 75% of triplet excitons are deactivated through non-radiative transitions, and the theoretical limit of the device's internal quantum efficiency is 25%. In order to improve the utilization of excitons, it is necessary to convert triplet excitons into photons to achieve 100% internal quantum efficiency. Phosphorescent metal complexes can convert triplet excitons into photons by utilizing the spin-orbit coupling of heavy metal atoms, but this approach faces the problem of expensive phosphorescent metal complexes. Another way to utilize triplet excitons is to develop luminescent materials with thermally activated delayed fluorescence (TADF) properties, which utilize the thermally activated reverse intersystem crossing (RISC) process to transfer the triplet excited state to the singlet excited state to emit fluorescence, thereby fully utilizing singlet and triplet excitons. Molecules with TADF properties generally must meet two conditions: a small singlet-triplet energy level difference (ΔE ST ) and higher fluorescence quantum efficiency (PLQY). On the one hand, the smaller ΔE ST It is conducive to the occurrence of thermally activated reverse intersystem crossing process, which is conducive to improving the utilization efficiency of triplet excitons; on the other hand, the material must have a high PLQY, thereby promoting the decay of singlet excitons in the form of light and improving device efficiency.

[0003] At present, the main approach to developing TADF molecules is to introduce donor (D) and acceptor (A) groups so that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are effectively separated in space, thereby achieving a small ΔE ST However, this DA structure exhibits a large Stokes shift (abbreviated as: Stokes shift) due to the vibrational relaxation of its excited state, and the luminescence spectrum is wide, with the full width at half maximum (FWHM) generally ranging from 70nm to 100nm. In practical applications, it is often necessary to use filters or construct optical microcavities to improve color purity, but this will lead to a decrease in the external quantum efficiency of the device or a complex device structure.

[0004] Therefore, how to develop fluorescent materials that have both TADF effect and narrow spectral characteristics through appropriate chemical structure design to solve the defect of wide half-width faced by the above materials has become one of the urgent problems to be solved by many forward-looking researchers in the field.

[0005] In view of the above reasons, the present invention is proposed. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a boron-containing heterocyclic compound, an organic electroluminescent material, and an organic electroluminescent element. When the boron-containing heterocyclic compound of the present invention is used as a luminescent material, it emits deep blue to blue light with high luminous efficiency.

[0007] The first object of the present invention is to provide a boron-containing heterocyclic compound.

[0008] The second object of the present invention is to provide an organic electroluminescent material.

[0009] The third object of the present invention is to provide an organic electroluminescent element.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A boron-containing heterocyclic compound, the general structural formula of the boron-containing heterocyclic compound is shown in Formula I:

[0012]

[0013] Where: X 1 、X 2 、X 3 、X 4 Each independently selected from N or CR 6 ;

[0014] Ring A, Ring B, and Ring C are each independently selected from substituted or unsubstituted C6-C 60 Aromatic ring, substituted or unsubstituted C2-C 60 Groups consisting of heteroaromatic rings;

[0015] Y 1 、Y 2 、Y 3 Each independently selected from a single bond, O, S, Se, CR 7 R 8 、SiR 7 R 8 NR 9 Or no Y 1 、Y 2 or Y 3 ;

[0016] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9are the same as or different from each other and are independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C 30 Alkyl, substituted or unsubstituted C6~C 50 Aryl, substituted or unsubstituted C3~C 30 Cycloalkyl, substituted or unsubstituted C2~C 50 Heteroaryl, substituted or unsubstituted C1~C 30 Alkoxy, substituted or unsubstituted C6~C 50 Aryloxy, substituted or unsubstituted C1~C 30 Alkylthio, substituted or unsubstituted C6~C 50 Arylthio, substituted or unsubstituted C1~C 30 Alkylamino, substituted or unsubstituted C6~C 50 Arylamine, substituted or unsubstituted C1~C 30 Alkylsilyl, substituted or unsubstituted C6~C 50 A group consisting of an arylsilyl group, a nitro group, a cyano group or a halogen atom, any two or more adjacent R 1 ~R 9 They may be arbitrarily joined or fused to form a substituted or unsubstituted ring, and the formed ring may contain or not contain heteroatoms N, O, S, P, B, Si or Se;

[0017] R 3 、R 4 、R 5 One or more substituents to saturation.

[0018] Furthermore, the boron-containing heterocyclic compound is selected from any one of the following structures:

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] Among them, Y 4 Each independently selected from O, S, Se or NR 9 ;

[0025] R 1 ~R 9 、X 1 ~X 4 、Y 1~Y 3 The definitions of are the same as those of formula I.

[0026] Furthermore, the Y 1 、Y 2 、Y 3 Each independently selected from O, S, Se or NR 9 .

[0027] Furthermore, there is no Y 1 .

[0028] Furthermore, there is no Y 2 .

[0029] Furthermore, there is no Y 3 .

[0030] Furthermore, the X 1 ~X 4 Each independently CR 6 .

[0031] Furthermore, the R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 At each occurrence, each is independently selected from the group consisting of hydrogen, deuterium, methyl, ethyl, isopropyl, tert-butyl, fluorine, nitrile, trimethylsilyl, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted quaterphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted triphenylene, substituted or unsubstituted anthracenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted fluorenyl, and substituted or unsubstituted carbazolyl.

[0032] An aryl group in the sense of the present invention contains 6 to 50 carbon atoms, a heteroaryl group in the sense of the present invention contains 2 to 50 carbon atoms and at least one heteroatom, with the proviso that the total number of carbon atoms and heteroatoms is at least 5; the heteroatoms are preferably selected from N, O or S. An aryl or heteroaryl group here is in particular a radical derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, Perylene, fluoranthene, tetracene, pentacene, benzopyrene, biphenyl, phenylene, terphenyl, triphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, trimerized indene, isotrimerized indene, spirotrimerized indene, spiroisotrimerized indene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline , isoquinoline, acridine, phenanthridine, benzo[5,6]quinoline, benzo[6,7]quinoline, benzo[7,8]quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthriimidazole, pyridimidazole, pyrazinimidazole, quinoxalinoimidazole, oxazole, benzoxazole, naphthioxazole, anthraquinoxazole, phenanthrioxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, hexaazatriphenylene, benzopyridazine, pyrimidine, benzene and pyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorescein ring, naphthyridine, azacarbazole, benzocarboline, carboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine, quinazoline and benzothiadiazole or radicals derived from combinations of these systems.

[0033] The condensed aromatic group used in the present invention refers to a monovalent functional group obtained by removing one hydrogen atom from an aromatic hydrocarbon having 6 to 50 carbon atoms and combining two or more rings. In this case, the two or more rings may be attached to each other in a simple or condensed form. Non-limiting examples thereof include phenanthrenyl, anthracenyl, fluoranthenyl, pyrenyl, triphenylene, perylene, Ji et al.

[0034] The arylamine group used in the present invention refers to an amine substituted with an aryl group having 6 to 50 carbon atoms. Non-limiting examples of arylamine groups include diphenylamine, N-phenyl-1-naphthylamine, and N-(1-naphthyl)-2-naphthylamine. A heteroarylamine group refers to an amine substituted with an aryl group having 6 to 50 carbon atoms and a heteroaryl group having 2 to 50 carbon atoms. Non-limiting examples of heteroarylamine groups include N-phenylpyridin-3-amine, N-([1,1'-biphenyl]-4-yl)dibenzo[b,d]furan-2-amine, and N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine.

[0035] An aliphatic hydrocarbon or alkyl radical having 1 to 30 carbon atoms and in which individual hydrogen atoms or -CH2- groups may also be replaced by the above-mentioned radicals is preferably taken to mean, within the meaning of the present invention, a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, cyclopentyl, n-hexyl, neohexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl or cyclooctenyl radical.

[0036] Alkoxy groups are preferably alkoxy groups having 1 to 30 carbon atoms, which are taken to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, sec-pentoxy, 2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptyloxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy and 2,2,2-trifluoroethoxy.

[0037] Heteroalkyl is preferably an alkyl radical having 1 to 30 carbon atoms and is understood to mean a radical in which individual hydrogen atoms or -CH2- groups may be replaced by oxygen, sulfur or halogen atoms, and is understood to mean alkoxy, alkylthio, fluorinated alkoxy, fluorinated alkylthio, in particular methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, isobutylthio, sec-butylthio, tert-butylthio, trifluoromethylthio, trifluoromethoxy, pentafluoroethoxy, pentafluoroethylthio, 2,2,2-trifluoroethoxy, 2,2,2-trifluoroethylthio, vinyloxy, vinylthio, propenyloxy, propenylthio, butenylthio, butenyloxy, pentenyloxy, pentenylthio, cyclopentenyloxy, cyclopentenylthio, hexenyloxy, hexenylthio, cyclohexenyloxy, cyclohexenylthio, ethynyloxy, ethynylthio, propynyloxy, propynylthio, butynyloxy, butynylthio, pentynyloxy, pentynylthio, hexynyloxy, hexynylthio.

[0038] Generally speaking, the cycloalkyl group in the present invention can be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptyl, or cycloheptenyl, wherein one or more -CH2- groups can be replaced by the above groups; in addition, one or more hydrogen atoms can also be replaced by a deuterium atom, a halogen atom, or a nitrile group.

[0039] The alkylamino group used in the present invention refers to an amine substituted by an alkyl group having 1 to 30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms. Non-limiting examples of the alkylamino group include dimethylamino, diethylamino, dipropylamino, diisopropylamino, and the like.

[0040] The alkenyl or alkynyl group in the present invention has 2 to 30 carbon atoms, and the individual hydrogen atoms of the alkenyl or alkynyl group may be substituted by the above-mentioned alkyl group, preferably vinyl, propenyl, butenyl, isobutenyl, styryl, distyryl, ethynyl, propynyl, butynyl, phenylethynyl; in addition, one or more hydrogen atoms may be replaced by a deuterium atom, a halogen atom or a nitrile group.

[0041] The aryloxy group used in the present invention refers to R'O - The monovalent functional group represented by is an aryl group having 6 to 50 carbon atoms. Non-limiting examples of such an aryloxy group include phenoxy, naphthyloxy, biphenyloxy, and the like.

[0042] The arylthio group used in the present invention refers to R'S - The monovalent functional group represented by is an aryl group having 6 to 50 carbon atoms. Non-limiting examples of such an arylthio group include phenylthio, naphthylthio, biphenylthio and the like.

[0043] The alkylsilyl group used in the present invention refers to a silyl group substituted by an alkyl group having 1 to 30 carbon atoms. The number of carbon atoms constituting the alkylsilyl group is at least 3. Non-limiting examples of the alkylsilyl group include trimethylsilyl and triethylsilyl. The arylsilyl group refers to a silyl group substituted by an aryl group having 6 to 50 carbon atoms.

[0044] The arylphosphino group used in the present invention refers to a diarylphosphino group substituted with an aryl group having 6 to 50 carbon atoms. Non-limiting examples of arylphosphino groups include diphenylphosphino and bis(4-trimethylsilylphenyl)phosphino. An aryloxyphosphino group is a diarylphosphino group in which the phosphorus atom is oxidized to its highest valence state.

[0045] The arylboryl group used in the present invention refers to a diarylboryl group substituted with an aryl group having 6 to 50 carbon atoms. Non-limiting examples of the arylboryl group include diphenylboryl and di(2,4,6-trimethylphenyl)boryl. The alkylboryl group refers to a dialkylboryl group substituted with an alkyl group having 1 to 30 carbon atoms. Non-limiting examples of the alkylboryl group include di-tert-butylboryl and diisobutylboryl.

[0046] "Halo", "halogen", "halogen atom", "halo" within the meaning of the present invention are used interchangeably and refer to fluorine, chlorine, bromine or iodine.

[0047] As used herein, "combinations thereof" or "groups thereof" means that one or more members of an applicable list are combined to form known or chemically stable arrangements that one of ordinary skill in the art can conceive from the applicable list. For example, alkyl and deuterium can be combined to form partially or fully deuterated alkyl groups; halogen and alkyl can be combined to form haloalkyl substituents, such as trifluoromethyl and the like; and halogen, alkyl, and aryl can be combined to form haloaralkyl groups.

[0048] In the present specification, the term "substituted or unsubstituted" means a group selected from hydrogen, deuterium, a halogen atom, a hydroxyl group, a nitrile group, a nitro group, an amino group, an amidine group, a hydrazine group, a hydrazone group, a carboxyl group or a carboxylate thereof, a sulfonic acid group or a sulfonate thereof, a phosphoric acid group or a phosphate thereof, a C1-C 30 Alkyl, C2-C 30 Alkenyl, C2-C 30 Alkynyl, C1-C 30 Alkoxy, C3-C 30 Cycloalkyl, C3-C 30 Cycloalkenyl, C6-C 50 Aryl, C6-C 50 Aryloxy, C6-C 50 Aryl sulfide group and C2-C 50 The heterocyclic aryl group may be substituted or unsubstituted with one or more substituents, or may be substituted or unsubstituted with a substituent formed by linking two or more of the substituents exemplified above.

[0049] In one example, the term substituted includes combinations of two to four of the listed groups.

[0050] In another example, the term substitution includes a combination of two to three groups. In yet another example, the term substitution includes a combination of two groups. A preferred combination of substituents is a combination containing up to fifty atoms that are not hydrogen or deuterium, or a combination including up to forty atoms that are not hydrogen or deuterium, or a combination including up to thirty atoms that are not hydrogen or deuterium. In many cases, a preferred combination of substituents will include up to twenty atoms that are not hydrogen or deuterium.

[0051] In the present invention, "ring" in the substituted or unsubstituted ring formed by the bonding of adjacent groups refers to a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocycle. A condensed ring refers to a condensed aliphatic ring, a condensed aromatic ring, a condensed aliphatic heterocycle, a condensed aromatic heterocycle, or a combination thereof.

[0052] Furthermore, the compound of formula I is selected from one of the compounds represented by formulas B001 to B348:

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065] An organic electroluminescent material comprises the aforementioned boron-containing heterocyclic compound.

[0066] An organic electroluminescent element comprises a first electrode, a second electrode and at least one organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises the boron-containing heterocyclic compound.

[0067] Furthermore, the organic layer comprises one or more electron injection layers, electron transport layers, hole injection layers, hole transport layers, hole blocking layers, electron blocking layers and light-emitting layers.

[0068] Furthermore, the light-emitting layer includes the boron-containing heterocyclic compound described in the present invention.

[0069] Furthermore, the light-emitting layer includes a main material and a doping material, and the main material includes a compound composed of the following chemical groups: a group consisting of triphenylene, carbazole, dibenzothiophenyl, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, azadibenzothiophenyl, azadibenzofuran, azadibenzoselenophene and triazine.

[0070] Furthermore, the doping material includes the boron-containing heterocyclic compound.

[0071] wherein any substituent in the host material is independently selected from the group consisting of non-fused substituents: C n H 2n+1 , OC n H 2n+1 、OAr 3 、N(C n H 2n+1 )2、N(Ar 3 )(Ar 4 ), CH=CH-C n H 2n+1 、C≡CC n H 2n+1 、Ar 3 、Ar 3 -Ar 4 、C n H 2n -Ar 3 or no substituent, wherein n is an integer from 1 to 10; and wherein Ar 3 with Ar 4 Independently selected from the group consisting of phenyl, biphenyl, naphthyl, triphenylene, carbazolyl, and heteroaromatic analogs thereof.

[0072] Furthermore, the host material is selected from one or more of the compounds represented by formulas A1 to A93:

[0073]

[0074]

[0075]

[0076]

[0077] Furthermore, the mass ratio of the doping material to the host material is 1:99 to 50:50.

[0078] The organic electroluminescent material of the present invention may be composed of the boron-containing heterocyclic compound of the present invention alone, or may contain other compounds at the same time.

[0079] The present invention also includes an organic electroluminescent device comprising a cathode layer, an anode layer and at least one light-emitting layer. In addition to these layers, it may also comprise other layers, for example, in each case, comprising one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, exciton blocking layers, electron blocking layers and / or charge generation layers. An intermediate layer having, for example, an exciton blocking function may also be introduced between two light-emitting layers. However, it should be noted that each of these layers does not necessarily have to be present. The organic electroluminescent device described herein may comprise one light-emitting layer, or it may comprise multiple light-emitting layers. That is, a variety of light-emitting compounds capable of emitting light are used in the light-emitting layer. Particularly preferred is a system with three light-emitting layers, wherein the three layers can display blue, green and red light emission. If there is more than one light-emitting layer, according to the present invention, at least one of these layers comprises a compound of the present invention.

[0080] Furthermore, the organic electroluminescent element according to the present invention does not include a separate hole injection layer and / or hole transport layer and / or hole blocking layer and / or electron transport layer, that is, the light-emitting layer is directly adjacent to the hole injection layer or the anode layer, and / or the light-emitting layer is directly adjacent to the electron transport layer or the electron injection layer or the cathode layer.

[0081] In the other layers of the organic electroluminescent element according to the invention, in particular in the hole injection and hole transport layers and in the electron injection and electron transport layers, all materials can be used in the manner commonly used according to the prior art. A person skilled in the art will therefore be able to use all materials known for organic electroluminescent elements in combination with the light-emitting layer according to the invention without inventive step.

[0082] Furthermore, preference is given to organic electroluminescent components in which one or more layers can be applied by means of a sublimation process, wherein the organic electroluminescent components are deposited in a vacuum sublimation apparatus at temperatures below 10 -5 Pa, preferably less than 10 -6 The material is applied by vapor deposition at an initial pressure of 10 Pa. However, the initial pressure may also be even lower, for example below 10 -7 Pa.

[0083] Likewise preferred are organic electroluminescent components in which one or more layers can be applied by means of an organic vapor phase deposition method or by means of carrier gas sublimation, wherein at 10 -5 The material is applied at a pressure between 100 Pa and 1 Pa. A particular example of this method is the organic vapor jet printing method, in which the material is applied directly through a nozzle and is thus structured.

[0084] In addition, preferred organic electroluminescent elements are those in which one or more layers are produced from a solution, for example by spin coating, or by any desired printing method, such as screen printing, flexographic printing, lithography, photoinduced thermography, thermal transfer, inkjet printing or nozzle printing. Soluble compounds are obtained, for example, by modifying the boron-nitrogen compound by appropriate substitution. These methods are also particularly suitable for oligomers, dendrimers and polymers. Hybrid methods are also possible, in which, for example, one or more layers are applied from a solution and one or more further layers are applied by vapor deposition.

[0085] These methods are generally known to those skilled in the art, and they can apply them to the organic electroluminescent element comprising the boron-containing heterocyclic compound of the present invention without inventive effort.

[0086] The present invention therefore also relates to a method for producing an organic electroluminescent element according to the invention, wherein at least one layer can be applied by means of a sublimation method and / or by means of an organic vapor phase deposition method or by means of carrier gas sublimation and / or by means of spin coating from solution or by means of a printing method.

[0087] In addition, the present invention relates to a boron-containing heterocyclic compound of the present invention comprising at least one of the above-mentioned boron-containing heterocyclic compounds. The same preferred embodiments as those mentioned above for organic electroluminescent elements apply to the boron-containing heterocyclic compound of the present invention. In particular, the boron-containing heterocyclic compound may also preferably comprise other compounds. Processing the boron-containing heterocyclic compound of the present invention from the liquid phase, for example, by spin coating or by a printing method, requires a formulation according to the compound of the present invention. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, a mixture of two or more solvents may preferably be used. Suitable and preferred solvents are, for example, toluene, anisole, o-xylene, m-xylene or p-xylene, methyl benzoate, mesitylene, tetralin, o-dimethoxybenzene, tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, chlorobenzene, dioxane, phenoxytoluene, 3-phenoxytoluene, (-)-fennel, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, α-terpineol , benzothiazole, butyl benzoate, isopropylbenzene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, methyl benzoate, 1-methylpyrrolidone, p-cymene, phenethyl ether, 1,4-diisopropylbenzene, dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, or a mixture of these solvents.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] The present invention utilizes a compound containing a seven-membered ring containing a boron unit as the parent core as the luminescent unit. This utilizes the resonance effect between the boron, nitrogen, and oxygen atoms to separate the HOMO and LUMO, thereby achieving the TADF effect. Furthermore, structures such as carbazolyl, dibenzofuranyl, dibenzothiophenyl, benzofuranyl, benzothiophenyl, and phenoxazine groups can reduce the degree of structural relaxation in the excited state, thereby achieving a narrower half-width (FWHM). Furthermore, by introducing different substituents onto the rigid skeleton, the delayed fluorescence lifetime and FWHM can be further adjusted, resulting in a narrower luminescence peak width and higher efficiency compared to conventional compounds. Furthermore, the boron-containing heterocyclic compound exhibits high thermal stability, thereby extending the lifespan of organic electroluminescent devices containing it. Furthermore, the boron-containing heterocyclic compound improves solution solubility, thereby resolving the productivity and cost issues associated with conventional blue light materials. Furthermore, it can be used to prepare the luminescent layer in a solution process, rather than the existing evaporation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0091] Figure 1 A schematic diagram of an organic light-emitting device 100 is shown. The illustration is not necessarily drawn to scale. Device 100 may include a substrate 101, an anode layer 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a cathode layer 110, and a capping layer (CPL) 111. Device 100 can be fabricated by depositing the described layers in order.

[0092] Figure 2 A schematic diagram of an organic light-emitting device 200 showing two light-emitting layers. The device includes a substrate 201, an anode layer 202, a hole injection layer 203, a hole transport layer 204, a first light-emitting layer 205, an electron transport layer 206, a charge generation layer 207, a hole injection layer 208, a hole transport layer 209, a second light-emitting layer 210, an electron transport layer 211, an electron injection layer 212, and a cathode layer 213. Device 200 can be fabricated by sequentially depositing the described layers. While most common OLED devices have a single light-emitting layer, device 200 has a first light-emitting layer and a second light-emitting layer. The emission peaks of the first and second light-emitting layers can overlap, overlap, or not overlap. Materials similar to those described for device 100 can be used in the corresponding layers of device 200. Figure 2 An example of how to add some layers from the structure of the device 100 is provided. DETAILED DESCRIPTION

[0093] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0094] The "EQE" in the present invention refers to the external quantum efficiency of a device, that is, the ratio of the number of photons emitted by the device to the number of electrons injected into the device.

[0095] The organic electroluminescent element of the present invention comprises at least one organic layer disposed between an anode layer and a cathode layer and electrically connected to the anode layer and the cathode layer. Figure 1 A schematic diagram of an organic light-emitting device 100 is shown. The illustration is not necessarily drawn to scale. Device 100 may include a substrate 101, an anode layer 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a cathode layer 110, and a capping layer (CPL) 111. Device 100 can be fabricated by depositing the described layers in order.

[0096] Figure 2 A schematic diagram of an organic light-emitting device 200 containing two light-emitting layers is shown. The device includes a substrate 201, an anode layer 202, a hole injection layer 203, a hole transport layer 204, a first light-emitting layer 205, an electron transport layer 206, a charge generation layer 207, a hole injection layer 208, a hole transport layer 209, a second light-emitting layer 210, an electron transport layer 211, an electron injection layer 212, and a cathode layer 213. Device 200 can be fabricated by sequentially depositing the described layers. While most common OLED devices have a single monochromatic light-emitting layer or light-emitting layers having three primary colors, device 200 has two light-emitting layers of the same color. Materials similar to those described for device 100 can be used in the corresponding layers of device 200. Figure 2 One example is provided of how some layers may be added from the structure of device 100 .

[0097] Figure 1 and Figure 2The simple layered structure illustrated in is provided as a non-limiting example, and it will be understood that embodiments of the invention may be used in conjunction with a wide variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. Functional OLEDs may be achieved by combining the various layers described in different ways, or several layers may be omitted entirely, based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe the various layers as comprising a single material, it will be understood that combinations of materials may be used, such as a mixture of a host material and a dopant material, or more generally, a mixture. Also, the layers may have various sub-layers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 204 transports holes and injects holes into light-emitting layer 205, and may be described as a hole transport layer or an electron blocking layer. In one embodiment, the OLED may be described as having an organic layer disposed between a cathode layer and an anode layer. This organic layer may comprise a single layer or may further comprise, for example Figure 1 and Figure 2 Multiple layers of different organic materials are described.

[0098] Structures and materials not specifically described may also be used, such as PLEDs comprising polymeric materials. As another example, an OLED having a single organic layer or a stack of multiple layers may be used. The OLED structure may be separated from Figure 1 and Figure 2 For example, the substrate may include angled reflective surfaces to improve light coupling.

[0099] Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, organic vapor deposition methods, or applying one or more layers with the aid of carrier gas sublimation, wherein the layers are deposited at 10 -5 The material is applied at a pressure between mbar and 1 bar. A particular example of this method is the organic vapor jet printing method, in which the material is applied directly through a nozzle and is therefore structured. Other suitable deposition methods include, for example, spin coating, or by means of any desired printing method such as screen printing, flexographic printing, lithography, photoinduced thermography, thermal transfer, inkjet printing or nozzle printing, to produce one or more layers. Soluble compounds, for example, can be obtained by appropriate substitution. These methods are also particularly suitable for oligomers, dendrimers and polymers. Also feasible are hybrid methods, in which, for example, one or more layers are applied from solution and one or more additional layers are applied by vapor deposition.

[0100] Devices manufactured according to embodiments of the present invention may further optionally include a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damage due to exposure to harmful substances in the environment, including moisture, vapor and / or gas. The barrier layer may be deposited on the substrate, the electrode, under the substrate, the electrode, or next to the substrate, the electrode, or on any other part of the device, including the edge. The barrier layer may include a single layer or multiple layers. The barrier layer can be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials can be used for the barrier layer. The barrier layer may incorporate inorganic or organic compounds or both. Preferably, the barrier layer includes a mixture of a polymeric material and a non-polymeric material. In order to be considered a mixture, the aforementioned polymer and non-polymeric materials that make up the barrier layer should be deposited under the same conditions and / or at the same time. The weight ratio of the polymeric material to the non-polymeric material may be in the range of 95 / 5 to 5 / 95. In one example, the mixture of the polymeric material and the non-polymeric material essentially consists of polymeric silicon and inorganic silicon.

[0101] In any of the above-mentioned compounds used in each layer of the OLED element, the hydrogen atoms may be partially or fully deuterated. Thus, any of the specifically listed substituents, such as (but not limited to) methyl, phenyl, pyridyl, etc., may be in their non-deuterated, partially deuterated, and fully deuterated forms. Similarly, substituent groups (such as (but not limited to) alkyl, aryl, cycloalkyl, heteroaryl, etc.) may also be in their non-deuterated, partially deuterated, and fully deuterated forms.

[0102] The materials and structures described herein can be applied to elements other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can use the materials and structures.

[0103] Furthermore, organic devices such as organic transistors may utilize the materials and structures.

[0104] In the following examples of the present invention, conventional preparation methods were used unless otherwise specified. The raw materials used were all available from public commercial sources unless otherwise specified, and the percentages are by mass unless otherwise specified.

[0105] In order to explain the present invention more clearly, the technical solution of the present invention is described below with reference to some specific embodiments:

[0106] In the embodiment of the present invention, the performance testing conditions of the prepared electroluminescent device are as follows:

[0107] Chromaticity coordinates: tested using a spectrum scanner PhotoResearch PR-715;

[0108] Current-voltage: Tested using a Keithley 2420 digital source meter;

[0109] Power efficiency: tested using NEWPORT 1931-C;

[0110] Brightness: tested using a Minolta CS-1000A brightness meter.

[0111] Example 1

[0112] The preparation method of compound B008 comprises the following steps:

[0113] Step 1: Preparation of intermediate Int-1

[0114]

[0115] 25.0 mmol of 8-bromo-1-chloro-dibenzofuran (CAS: 2225909-61-3), 20.0 mmol of 3,6-di-tert-butylcarbazole, 30.0 mmol of sodium tert-butoxide, 0.1 mmol of Pd2(dba)3 catalyst, 0.2 mmol of Xantphos, and 120 mL of toluene were added. Under nitrogen protection, the temperature was raised to 100°C and stirred for reaction for 16 hours. The temperature was then cooled to room temperature, 50 mL of water was added, the organic phase was separated, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried, filtered, and the filtrate was concentrated under reduced pressure to dryness. The mixture was then recrystallized from toluene / THF to obtain Int-1 as a yellow solid in a yield of 84%.

[0116] Step 2: Preparation of intermediate Int-2

[0117]

[0118] To the mixture of 20.0 mmol of Int-1, 24.0 mmol of bipyralidoboric acid, 30.0 mmol of potassium acetate, 0.2 mmol of PdCl2(dppf)CH2Cl2 catalyst, and 2.0 mmol of cuprous iodide, 80 mL of DMF were added. Under nitrogen protection, the temperature was raised to 100°C and stirred for 15 hours. The temperature was then cooled to room temperature, and the reaction solution was poured into 250 mL of water and filtered. The filter cake was washed with water and recrystallized from toluene and ethanol to obtain Int-2 as a yellow solid in a yield of 78%.

[0119] Step 3: Preparation of intermediate Int-3

[0120]

[0121] 21.0 mmol of Int-2, 20.0 mmol of 4-tert-butyl-2-iodobromobenzene, 30.0 mmol of hydrated potassium phosphate, and 0.01 mmol of Pd(PPh3)4 catalyst were mixed, and then 60 mL of toluene, 40 mL of ethanol, and 30 mL of water were added. Under nitrogen protection, the temperature was raised to reflux and stirred for reaction for 5 hours, then cooled to room temperature, the organic phase was separated, the aqueous phase was extracted with ethyl acetate, the organic phase was dried, filtered, and the filtrate was concentrated under reduced pressure and recrystallized from toluene / THF to obtain yellow solid Int-3 with a yield of 72%.

[0122] Step 4: Preparation of compound B008

[0123]

[0124] Under nitrogen protection, 10.0 mmol of Int-3 prepared in the previous step was mixed with 60 mL of dry tert-butylbenzene and 20 mL of dry THF, cooled to -78°C, and 12.0 mmol of 2.5 M n-butyllithium n-hexane solution was slowly added dropwise. The mixture was stirred and reacted for 10 minutes. Then 15.0 mmol of boron tribromide was added dropwise and stirred and reacted for 1 hour. Then 0.1 mol of triethylamine was added, and the mixture was heated to room temperature and stirred and reacted for 1 hour. The temperature was raised to 150°C and stirred and reacted for 5 hours. The mixture was cooled to room temperature, concentrated under reduced pressure and dried, and separated and purified by silica gel column chromatography to obtain compound B008 as a yellow solid with a yield of 37%. MS (TOF): m / z 586.3221 [M+H] + .

[0125] The following compounds were prepared by similar synthetic methods as described above:

[0126]

[0127]

[0128]

[0129] Example 2

[0130] The preparation method of compound B022 comprises the following steps:

[0131] Step 1: Preparation of intermediate Int-4

[0132]

[0133] To the mixture of 22.0 mmol of 2,4,6,8-tetra-tert-butyl-10H-benzoxazine (CAS: 55649-30-4), 20.0 mmol of m-bromoiodobenzene, 40.0 mmol of potassium carbonate, 2.2 mmol of cuprous iodide, and 6.6 mmol of N,N'-dimethylethylenediamine, 120 mL of toluene were added. Under nitrogen protection, the temperature was raised to reflux with stirring for 15 hours, then cooled to room temperature, filtered, and the filter cake was washed with toluene. The filtrate was flushed through a short silica gel column and eluted with toluene. The column was concentrated under reduced pressure and recrystallized from toluene / THF to obtain Int-4 as a yellow solid in a yield of 87%.

[0134] Step 2: Preparation of intermediate Int-5

[0135]

[0136] 20.0 mmol of Int-4, 22.0 mmol of 1-bromo-dibenzofuran-9-boronic acid, 30.0 mmol of hydrated potassium phosphate, and 0.01 mmol of Pd(PPh3)4 catalyst were mixed, and then 60 mL of toluene, 40 mL of ethanol, and 40 mL of water were added. Under nitrogen protection, the temperature was raised to reflux and stirred for 5 hours, then cooled to room temperature, the organic phase was separated, the aqueous phase was extracted with ethyl acetate, the organic phase was dried, filtered, and the filtrate was concentrated under reduced pressure and recrystallized from toluene / THF to obtain yellow solid Int-5 with a yield of 74%.

[0137] Step 3: Preparation of compound B022

[0138]

[0139] Under nitrogen protection, 10.0 mmol of Int-5 prepared in the previous step and 60 mL of dry tert-butylbenzene were mixed, cooled to -78°C, and 12.0 mmol of 2.5 M n-butyllithium n-hexane solution was slowly added dropwise. The reaction was stirred for 10 minutes, and then 15.0 mmol of boron tribromide was added dropwise. The reaction was stirred for 1 hour. Then 0.1 mol of triethylamine was added, and the temperature was raised to room temperature and stirred for 1 hour. The temperature was raised to 150°C and stirred for 5 hours. The mixture was cooled to room temperature, concentrated under reduced pressure and dried, and then purified by silica gel column chromatography to obtain compound B022 as a yellow solid with a yield of 35%. MS (TOF): m / z 658.3792 [M+H] + .

[0140] The following compounds were prepared by similar synthetic methods as described above:

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] Example 3

[0149] The preparation method of compound B278 comprises the following steps:

[0150] Step 1: Preparation of intermediate Int-6

[0151]

[0152] 24.0 mmol of 4-(3-bromophenyl)-9-phenyl-9H-carbazole (CAS: 2088030-59-3), 20.0 mmol of 5-tert-butyl-N-(4-tert-butylphenyl)benzo[b]thiophene-3-amine (CAS: 2648147-42-4), 30.0 mmol of sodium tert-butoxide, 0.2 mmol of Pd2(dba)3, 0.5 mmol of a 30% tert-butylphosphine toluene solution, and 120 mL of toluene were added. Under nitrogen protection, the temperature was raised to 90°C with stirring to react for 12 hours, then cooled to room temperature, 50 mL of water was added, the organic phase was separated, the aqueous phase was extracted with toluene, the organic phase was dried, filtered, and the filtrate was applied to a short silica gel column, eluted with toluene, concentrated to dryness under reduced pressure, and then recrystallized from toluene / THF to obtain Int-6 as a yellow solid in a yield of 82%.

[0153] Step 2: Preparation of compound B278

[0154]

[0155] Under nitrogen protection, 10.0 mmol of Int-6 prepared in the previous step was mixed with 40 mL of dry tert-butylbenzene and 20 mL of dry THF, cooled to -78°C, and 12.0 mmol of 2.5 M n-butyllithium n-hexane solution was slowly added dropwise. The mixture was stirred for 10 minutes, heated to room temperature and stirred for 1 hour, cooled to -78°C, and then 15.0 mmol of boron tribromide was added dropwise. The mixture was stirred for 1 hour, and then 0.1 mol of triethylamine was added. The mixture was heated to room temperature and stirred for 1 hour. The mixture was heated to 150°C and stirred for 5 hours. The mixture was cooled to room temperature, concentrated under reduced pressure and dried, and then purified by silica gel column chromatography to obtain compound B278 as a yellow solid with a yield of 31%. MS (TOF): m / z 663.2945 [M+H]. + .

[0156] The following compounds were prepared by similar synthetic methods as described above:

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165]

[0166] Example 4

[0167] The preparation method of compound B310 comprises the following steps:

[0168] Step 1: Preparation of intermediate Int-7

[0169]

[0170] Referring to the synthesis method of the first step of Example 3, the 4-(3-bromophenyl)-9-phenyl-9H-carbazole in the first step of Example 3 was replaced with 4-tert-butylbromobenzene, and the 5-tert-butyl-N-(4-tert-butylphenyl)benzo[b]thiophene-3-amine was replaced with 2-bromo-10H-phenoxazine to prepare compound Int-7 as a white solid in a yield of 76%.

[0171] Step 2: Preparation of intermediate Int-8

[0172]

[0173] Referring to the synthesis method of the second step of Example 2, Int-4 in the second step of Example 2 was replaced with Int-7, and 1-bromo-dibenzofuran-9-boronic acid was replaced with (2-(5-tert-butylbenzo[b]thiophen-3-yl)phenyl)boronic acid to prepare compound Int-8, a yellow solid, with a yield of 75%.

[0174] Step 3: Preparation of compound B310

[0175]

[0176] Referring to the synthesis method of the second step of Example 3, except that Int-6 in the second step of Example 3 was replaced with Int-8, compound B310 was prepared as a yellow solid in a yield of 35%. MS (TOF): m / z 588.2472 [M+H] + .

[0177] Referring to the above similar synthetic method, the following compounds were prepared

[0178]

[0179]

[0180]

[0181]

[0182]

[0183]

[0184]

[0185] Example 5

[0186] An OLED element 100, such as Figure 1 As shown, the OLED element of this embodiment is a top-emitting element, including a substrate 101, an anode layer 102 provided on the substrate 101, a hole injection layer 103 provided on the anode layer 102, a hole transport layer 104 provided on the hole injection layer 103, an electron blocking layer 105 provided on the hole transport layer 104, a light-emitting layer 106 provided on the electron blocking layer 105, a hole blocking layer 107 provided on the light-emitting layer 106, an electron transport layer 108 provided on the hole blocking layer 107, an electron injection layer 109 provided on the electron transport layer 108, a cathode 110 provided on the electron injection layer 109, and a capping layer 111 on the cathode. The preparation method of the OLED element without the hole blocking layer 107 comprises the following steps:

[0187] (1) The glass substrate coated with the ITO conductive layer was ultrasonically treated in a cleaning agent for 30 minutes, rinsed in deionized water, ultrasonically treated in an acetone / ethanol mixed solvent for 30 minutes, baked in a clean environment until completely dry, irradiated with an ultraviolet light cleaner for 10 minutes, and bombarded with a low-energy cation beam. The treated ITO glass substrate was placed in a vacuum chamber and evacuated to a vacuum of less than 1×10 -5 Pa, metallic silver is evaporated on the above ITO film with a film thickness of An anode layer is obtained.

[0188] (2) Compounds HI01 and HI02 were further evaporated on the anode layer as hole injection layers, wherein HI02 was 3% of the mass of HI01 and the thickness of the evaporated film was HTM is continuously evaporated on the hole injection layer to form a hole transport layer with a thickness of

[0189] (3) Continue to evaporate a layer of compound HT202 on the hole transport layer as an electron blocking layer, and the evaporated film thickness is

[0190] (4) A layer of the boron-containing heterocyclic compound represented by formula I of the present invention and A86 is continuously evaporated on the electron blocking layer as an organic light-emitting layer, wherein A86 is the main material and the boron-containing heterocyclic compound represented by formula I of the present invention is the doping material, the doping concentration of the boron-containing heterocyclic compound represented by formula I in A86 is 6%, and the evaporated film thickness is

[0191] (5) A layer of compound LiQ and ET205 is further evaporated on the above-mentioned light-emitting layer as the electron transport layer of the device, wherein the mass ratio of LiQ and ET205 is 1:1, and the evaporated film thickness is

[0192] (6) A layer of LiF compound is further evaporated on the above electron transport layer as the electron injection layer of the element, and the thickness of the evaporated film is

[0193] (7) On the electron injection layer, magnesium and silver were evaporated as the cathode layer of the element, wherein the mass ratio of magnesium to silver was 2:1 and the thickness of the evaporated film was

[0194] (8) Compound HT038 was evaporated on the cathode layer as a capping layer with a film thickness of

[0195] The structural formula of the compound used in this embodiment is shown below:

[0196]

[0197] Comparative Example 1

[0198] An organic electroluminescent device was prepared according to the same steps as in Example 5, except that compound BD030 was used instead of the boron-containing heterocyclic compound of the present invention.

[0199] The structure of compound BD030 is:

[0200]

[0201] Test Example 1

[0202] The organic electroluminescent devices prepared in Example 5 and Comparative Example 1 were subjected to performance testing. Specifically, the voltage was increased at a rate of 0.1 V per second to measure the brightness of the organic electroluminescent element when it reached 1000 cd / m 2 The voltage at which the luminance is measured 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 LT95% life test is as follows: use a luminance meter at 1000cd / m 2 Under the same brightness, the current is kept constant and the brightness decay of the organic electroluminescent element is measured to be 950cd / m 2 The time is in hours. The data listed in Table 1 are relative data compared with Comparative Example 1. The results are shown in Table 1.

[0203] Table 1 Performance test results

[0204]

[0205]

[0206]

[0207]

[0208]

[0209]

[0210]

[0211]

[0212] The above experimental data show that the compounds of the present invention achieve the separation of HOMO and LUMO through the resonance effect of heterocyclic compounds formed by heteroatoms such as boron-nitrogen or boron-oxygen, thereby achieving the TADF effect. At the same time, the hybrid units of boron atoms and nitrogen atoms and the large planar conjugated groups have a rigid skeleton structure, which can reduce the degree of relaxation of the excited state structure, thereby achieving a narrow half-peak width, low driving voltage, and high luminous efficiency. As a blue light doping material, a blue light organic electroluminescent element was obtained. Compared with the organic electroluminescent element using BD030 as a blue light doping material, the difference is that the boron atom of BD030 is connected to one side of the benzene ring in carbazole, and the planar conjugation is weak, while the boron atom of the boron-containing heterocyclic compound of the present invention is embedded in a large seven-membered ring such as carbazole, dibenzofuran, dibenzothiophene or fluorene, forming a large conjugated plane with strong conjugation ability. Therefore, the compound of the present invention performs better in device performance.

[0213] Possible industrial applications of the compounds of the present invention:

[0214] Organic electroluminescent devices containing the compounds of the present invention can be used in wall-mounted televisions, flat-panel displays, flat-panel lighting devices such as lighting, backlight sources for copiers, printers, liquid crystal displays, light sources for measuring instruments, display panels, signage, etc.

[0215] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A boron-containing heterocyclic compound, characterized in that The boron-containing heterocyclic compound is selected from any one of the following structures: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 ； Among them, Y 1 、Y 2 、Y 3 、Y 4 Each independently selected from O, S or NR 9 ; X 1 ~X 4 Each independently CR 6 ; R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 At each occurrence, each is independently selected from the group consisting of hydrogen, deuterium, methyl, ethyl, isopropyl, tert-butyl, fluorine, nitrile, trimethylsilyl, phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, phenanthrenyl, triphenylene, anthracenyl, dibenzofuranyl, dibenzothiophenyl, fluorenyl, and carbazolyl.

2. A boron-containing heterocyclic compound, characterized in that The boron-containing heterocyclic compound is selected from one of the following compounds:

3. An organic electroluminescent material, characterized in that: The invention comprises the boron-containing heterocyclic compound according to any one of claims 1 to 2.

4. An organic electroluminescent element comprising a first electrode, a second electrode, and at least one organic layer disposed between the first electrode and the second electrode, characterized in that: The organic layer comprises the boron-containing heterocyclic compound according to any one of claims 1 to 2.

5. The organic electroluminescent element according to claim 4, wherein The organic layer comprises one or more electron injection layers, electron transport layers, hole injection layers, hole transport layers, hole blocking layers, electron blocking layers and light-emitting layers; the light-emitting layer comprises the boron-containing heterocyclic compound according to any one of claims 1-2.

6. The organic electroluminescent element according to claim 5, wherein The light-emitting layer also includes a main material and a dopant material, wherein the main material includes a compound composed of the following chemical groups: a group consisting of triphenylene, carbazole, dibenzothiophenyl, dibenzofuranyl, dibenzoselenophene, azatriphenylene, azacarbazole, azadibenzothiophenyl, azadibenzofuranyl, azadibenzoselenophene and triazine; and the dopant material includes the boron-containing heterocyclic compound according to any one of claims 1 to 2.

7. The organic electroluminescent element according to claim 6, wherein: The mass ratio of the doping material to the main material is 1:99~50:

50.

8. Use of the boron-containing heterocyclic compound according to any one of claims 1 to 2 in an organic electroluminescent device.

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