A compound containing two boron atoms and its application

Abstract

The present invention provides a compound containing two boron atoms, an organic electroluminescent element, and an organic electroluminescent material, wherein the compound containing two boron atoms has a structural formula as shown in Formula I. Compared with the prior art, the present invention uses a compound containing two boron atoms as a light-emitting unit, and on the one hand, the resonance effect between the boron atom and the nitrogen atom can be used to achieve the separation of HOMO and LUMO, thereby achieving the TADF effect, and at the same time, the hybrid unit of the boron atom and the nitrogen atom has a rigid skeleton structure, which can reduce the degree of structural relaxation of the excited state, thereby achieving a narrower half-peak width; on the other hand, by introducing different substituents on the rigid skeleton, the delayed fluorescence lifetime and half-peak width can be further adjusted.

Description

Technical Field

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

[0002] Due to the limitation of the 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 by non-radiative transitions, and the theoretical limit of the internal quantum efficiency of the device 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 using 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, and use 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 (△E 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 beneficial 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 due to the vibrational relaxation of its excited state, and the luminescence spectrum is wide, with a half-width at half maximum (FWHM) generally between 70nm and 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 complicated 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 of the peak 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 compound containing two boron atoms, an organic electroluminescent element, and an organic electroluminescent material. When the compound containing two boron atoms described in the present invention is used as a luminescent material, it emits deep blue to blue light and has high luminescent efficiency.

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

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

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

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

[0011] A compound containing two boron atoms, wherein the general structural formula of the compound containing two boron atoms is as shown in Formula I:

[0012]

[0013] Wherein: Ring A, B, C, D are each independently selected from substituted or unsubstituted C6-C 50 Aryl, substituted or unsubstituted C6~C 50 Aromatic amino, substituted or unsubstituted C2~C 50 The group consisting of heteroaryl;

[0014] Ar 1 ,Ar 2 Each independently selected from substituted or unsubstituted C1 to 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 C6~C 50 Aryloxy, substituted or unsubstituted C5~C 50 Arylthio, substituted or unsubstituted C5~C 50 Arylamine, substituted or unsubstituted C5~C 50 The group consisting of arylsilyl.

[0015] Furthermore, the compound containing two boron atoms is selected from any one of the following structures:

[0016]

[0017]

[0018] Among them, G 1 , G 2 , G 3 , G 4 Each independently selected from O, S, NR 9 、SiR 9 R 10 or BR 9 ;X 1 , X 2 , X 3 , X 4 Each independently selected from a single bond, O, S, NR 9 , CR 9 R 10 、SiR 9 R 10 or BR 9 ;

[0019] R 1 ~R 10 At each occurrence, each is independently selected from hydrogen, deuterium, fluorine, 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 The group consisting of arylsilyl and nitrile.

[0020] Furthermore, the G 1 , G 2 , G 3 , G 4 Each is independently selected from O or S.

[0021] Furthermore, the X 1 , X 2 , X 3 , X 4Each independently selected from a single bond, O, S, NR 9 , CR 9 R 10 or SiR 9 R 10 ;

[0022] R 1 ~R 8 at each occurrence, is independently selected from the group consisting of hydrogen, deuterium, methyl, ethyl, isopropyl, tert-butyl, fluorine, nitrile or trimethylsilyl;

[0023] R 9 , R 10 Each occurrence is independently selected from methyl, ethyl, isopropyl, tert-butyl, substituted or unsubstituted C6-C 50 Aryl, substituted or unsubstituted C3~C 30 Cycloalkyl, substituted or unsubstituted C2~C 50 Heteroaryl, substituted or unsubstituted C6~C 50 A group consisting of arylamine groups.

[0024] 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 sum 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 refers in particular to a group derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, Perylene, fluoranthene, tetracene, pentacene, benzopyrene, biphenyl, isophenyl, terphenyl, triphenyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, trimerized indene, isotrimerized indene, spirotrimerized indene, spiroistrimerized 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, phenanthimidazole, pyridimidazole, pyrazinimidazole, quinoxalinoimidazole, oxazole, benzoxazole, naphthimidazole, anthraoxazole, phenanthromoxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, hexaazatriphenylene, benzopyridazine, pyrimidine, benzene 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.

[0025] Aliphatic hydrocarbon or alkyl radicals having 1 to 30 carbon atoms and in which individual hydrogen atoms or -CH2- groups may also be replaced by the above-mentioned radicals are preferably taken to mean the following radicals: 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. Alkoxy is preferably an alkoxy radical having 1 to 30 carbon atoms, and is 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. Heteroalkyl is preferably an alkyl radical having 1 to 30 carbon atoms, and is taken to mean radicals in which individual hydrogen atoms or -CH2- groups may be replaced by oxygen, sulfur or halogen atoms, and is taken to mean alkoxy, alkylthio, fluorinated alkoxy, fluorinated alkylthio, and 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.

[0026] In general, the cycloalkyl group according to the present invention may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptyl, cycloheptenyl, wherein one or more -CH2- groups may be replaced by the above groups; in addition, one or more hydrogen atoms may also be replaced by a deuterium atom, a halogen atom or a nitrile group.

[0027] 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 60 Alkyl, C2-C 60 Alkenyl, C2-C 60 Alkynyl, C1-C 60 Alkoxy, C3-C 60 Cycloalkyl, C3-C60 Cycloalkenyl, C6-C 60 Aryl, C6-C 60 Aryloxy, C6-C 60 Aryl sulfide group and C2-C 60 The heterocyclic aryl group may be substituted or unsubstituted with one or more substituents, or may be substituted or unsubstituted with a substituent in which two or more substituents among the substituents exemplified above are linked together.

[0028] Furthermore, the compound of formula I is selected from one of the compounds represented by formulas B001 to B138:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] An organic electroluminescent material, characterized by comprising the aforementioned compound containing two boron atoms.

[0039] 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 compound containing two boron atoms.

[0040] 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.

[0041] Further, the light-emitting layer includes a main compound and a dopant, 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; the dopant includes the compound containing two boron atoms;

[0042] 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 1 、N(C n H 2n+1 )2、N(Ar 1 )(Ar 2 ), CH=CH-C n H 2n+1 、C≡CC n H 2n+1 ,Ar 1 ,Ar 1 -Ar 2 , C n H 2n -Ar 1 or no substituent, wherein n is an integer from 1 to 10; and wherein Ar 1 with Ar 2 Independently selected from the group consisting of phenyl, biphenyl, naphthyl, triphenylene, carbazolyl, and heteroaromatic analogs thereof.

[0043] Furthermore, the main compound is selected from one or more of the compounds represented by formulas A1 to A87:

[0044]

[0045]

[0046]

[0047]

[0048] Furthermore, the mass ratio of the dopant to the main material is 1:99 to 50:50.

[0049] The organic electroluminescent material in the present invention may be composed of the compound containing two boron atoms of the present invention alone, or may contain other compounds at the same time.

[0050] The present invention also includes an organic electroluminescent device, which comprises a cathode, an anode and at least one light-emitting layer. In addition to these layers, it may also include other layers, for example, in each case, 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 include one light-emitting layer, or it may include multiple light-emitting layers. That is, a variety of light-emitting compounds capable of emitting light are used in the light-emitting layer. A system with three light-emitting layers is particularly preferred, wherein the three layers can display blue, green and red light emission. If there are more than one light-emitting layer, then according to the present invention, at least one of these layers comprises a compound of the present invention.

[0051] Furthermore, the organic electroluminescent element according to the present invention does not contain 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, and / or the light-emitting layer is directly adjacent to the electron transport layer or the electron injection layer or the cathode.

[0052] 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 about organic electroluminescent elements in combination with the emitting layer according to the invention without inventive effort.

[0053] 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 sublimation reaction is carried out in a vacuum sublimation apparatus at temperatures below 10 °C. -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.

[0054] 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 of between 1000 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.

[0055] In addition, preferred organic electroluminescent elements are produced from solutions, for example by spin coating, or by means of any desired printing method, for example screen printing, flexographic printing, lithography, light-induced thermography, thermal transfer, inkjet printing or nozzle printing, to produce one or more layers. Soluble compounds, for example, obtained by modifying the boron-containing compound by appropriate substitution. These methods are also particularly suitable for oligomers, dendrimers and polymers. In addition, hybrid methods are feasible, in which, for example, one or more layers are applied from solution and one or more additional layers are applied by vapor deposition.

[0056] These methods are generally known to those skilled in the art, and they can apply them to organic electroluminescent elements comprising the compounds according to the invention without inventive step.

[0057] 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 at least one layer can be applied by means of an organic vapor deposition method or by means of carrier gas sublimation and / or at least one layer can be applied from a solution by spin coating or by means of a printing method.

[0058] In addition, the present invention relates to a compound containing two boron atoms according to the present invention comprising at least one of the above-mentioned. The same preferred conditions as indicated above for the organic electroluminescent element apply to the compound containing two boron atoms according to the present invention. In particular, the compound containing two boron atoms may also preferably contain other compounds in addition. The treatment of the compound containing two boron atoms according to the present invention from the liquid phase, for example by spin coating or by a printing method, requires a preparation according to the compound according to the present invention. These preparations 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, in particular 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-terpenes The solvents include 1,4-diisopropylbenzene, 2,4-diisopropylnaphthalene ...

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The compound containing two boron atoms of the present invention achieves a blue shift of the luminescent wavelength by amplifying the polarization direction of the BN rigid skeleton and maintaining a large HOMO and LUMO orbital overlap. It has a narrower luminescent peak width and higher efficiency than the previous compounds. At the same time, the compound containing two boron atoms has a higher thermal stability, thereby improving the life of the organic electroluminescent element containing the compound; in addition, the compound containing two boron atoms improves the solubility in the solution and solves the productivity and cost problems of the process of the previous blue light material, and can also be used to prepare the luminescent layer in the original process instead of the evaporation process but in the solution process. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0062] Figure 1 A schematic diagram of an organic light-emitting device 100 is shown. The illustration is not necessarily drawn to scale. The device 100 may include a substrate 101, an anode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, a cathode 109, and a capping layer (CPL) 110. The device 100 may be manufactured by depositing the described layers in order.

[0063] Figure 2 Schematic diagram of an organic light-emitting device 200 showing two light-emitting layers. The device includes a substrate 201, an anode 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 213. The device 200 can be prepared by depositing the described layers in sequence. Because the most common OLED device has one light-emitting layer, and the device 200 has a first light-emitting layer and a second light-emitting layer, the light emission peaks of the first light-emitting layer and the second light-emitting layer can be overlapping, cross-overlapping, or non-overlapping. In the corresponding layers of the device 200, materials similar to those described with respect to the device 100 can be used. Figure 2 One example is provided of how some layers may be added from the structure of device 100 . DETAILED DESCRIPTION

[0064] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0065] 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.

[0066] The organic electroluminescent element described in the present invention comprises at least one organic layer disposed between an anode and a cathode and electrically connected to the anode and the cathode. Figure 1A schematic diagram of an organic light-emitting device 100 is shown. The illustration is not necessarily drawn to scale. The device 100 may include a substrate 101, an anode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, an electron transport layer 107, an electron injection layer 108, a cathode 109, and a capping layer (CPL) 110. The device 100 may be manufactured by depositing the described layers in order.

[0067] 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 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 213. The device 200 can be prepared by depositing the layers described in sequence. Because the most common OLED device has a single-color light-emitting layer or a light-emitting layer having three primary colors, the device 200 has two light-emitting layers of the same light color. In the corresponding layers of the device 200, materials similar to those described with respect to the device 100 can be used. Figure 2 One example is provided of how some layers may be added from the structure of device 100 .

[0068] Figure 1 and Figure 2 The simple layered structure illustrated in is provided as a non-limiting example, and it should be understood that embodiments of the present invention can be used in conjunction with a variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures can be used. Functional OLEDs can be achieved by combining the various layers described in different ways, or several layers can be omitted entirely, based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials different from those specifically described may be used. Although many of the examples provided herein describe various layers as including a single material, it will be understood that combinations of materials, such as a mixture of a matrix and a dopant, or more generally, a mixture, can be used. 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 and an anode. This organic layer may include a single layer or may further include, for example Figure 1 and Figure 2 Multiple layers of different organic materials are described.

[0069] Structures and materials not specifically described may also be used, such as PLEDs comprising polymer materials. As another example, an OLED having a single organic layer or multiple stacks 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.

[0070] 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 100 mbar and 1 bar. A particular example of this method is an 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, producing one or more layers by 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. Soluble compounds, for example, are obtained by appropriate substitution. These methods are also particularly suitable for oligomers, dendrimers and polymers. In addition, hybrid methods are feasible, in which, for example, one or more layers are applied from a solution and one or more additional layers are applied by vapor deposition.

[0071] The device manufactured according to the embodiment of the present invention may further optionally include a barrier layer. One purpose of the barrier layer is to protect the electrode and the organic layer from being damaged by exposure to harmful substances in the environment, including moisture, vapor and / or gas, etc. 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 may be formed by various known chemical vapor deposition techniques and may include a composition having a single phase and a composition having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic or organic compound or both. Preferably, the barrier layer includes a mixture of a polymeric material and a non-polymeric material. In order to be regarded as a mixture, the aforementioned polymer and non-polymeric materials constituting 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 is essentially composed of polymeric silicon and inorganic silicon.

[0072] In any of the above-mentioned compounds used in each layer of the above-mentioned OLED element, the hydrogen atoms may be partially or fully deuterated. Thus, any specific 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 classes (such as (but not limited to) alkyl, aryl, cycloalkyl, heteroaryl, etc.) may also be in their non-deuterated, partially deuterated, and fully deuterated forms.

[0073] The materials and structures described herein can be applied in elements other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can use the materials and structures.

[0074] Furthermore, organic devices such as organic transistors may use the materials and structures.

[0075] In the following examples of the present invention, conventional preparation methods are used unless otherwise specified. The raw materials used can be obtained from public commercial channels unless otherwise specified, and the percentages are by mass unless otherwise specified.

[0076] In order to explain the present invention more clearly, the technical solution of the present invention is described below in conjunction with some specific embodiments:

[0077] In the embodiments of the present invention, the performance testing conditions of the prepared electroluminescent device are as follows:

[0078] Chromaticity coordinates: tested using a spectrum scanner PhotoResearch PR-715;

[0079] Current-voltage: Tested using a digital source meter Keithley 2420;

[0080] Power efficiency: tested using NEWPORT 1931-C;

[0081] Brightness: Tested using a brightness meter Minolta CS-1000A.

[0082] Example 1

[0083] The preparation method of compound B030 comprises the following steps:

[0084] Step 1: Preparation of compound Int-1

[0085]

[0086] Under nitrogen protection, 20.0 mmol of 1,4-dibromo-2,5-diiodobenzene was dispersed in 80 mL of xylene, and 21.0 mmol of 3,6-di-tert-butylcarbazole, 0.1 mol of anhydrous potassium carbonate, 0.2 mmol of cuprous iodide and 0.6 mmol of N,N'-dimethylethylenediamine were added. The temperature was raised to reflux and stirred for reaction for 24 hours. After the reaction was completed, it was filtered, the filter cake was washed with dichloromethane, the filtrate was concentrated under reduced pressure, and purified by silica gel column to obtain Int-1 as a white solid with a yield of 86%.

[0087] Step 2: Preparation of compound Int-2

[0088]

[0089] Take 10.0mmol of the intermediate Int-1 prepared in the first step and mix it with 60mL of ethylene glycol dimethyl ether, then add 22.0mmol of (9,9-dimethyl-9,10-dihydroacridin-4-yl)boronic acid pinacol ester, 30.0mmol of potassium carbonate, 0.1mmol of Pd(PPh3)4 and 20mL of water. Under nitrogen protection, heat to 80°C and stir to react for 16 hours. After the reaction, add 50mL of water, extract with dichloromethane, collect the organic phase, dry it, filter it, concentrate the filtrate under reduced pressure and dry it, separate and purify it with silica gel column to obtain Int-2 with a yield of 73%.

[0090] Step 3: Preparation of compound B030

[0091]

[0092] Under nitrogen protection, 10.0 mmol of Int-2 prepared in the previous step and 120 mL of dry chlorobenzene were mixed, 22.0 mL of boron tribromide was slowly added dropwise, stirred for reaction for 1 hour, and then 0.1 mol of tributylamine was added dropwise, the temperature was raised to 150°C and stirred for reaction for 5 hours, cooled to room temperature, concentrated and dried under reduced pressure, and separated and purified by silica gel column to obtain compound B030 as a yellow solid with a yield of 36%. MS (MALDI-TOF): m / z 1062.59 [M + ], elemental analysis results: theoretical value: C, 85.87; H, 6.83; B, 2.03; N, 5.27(%); experimental value: C, 85.67; H, 6.97; B, 2.01; N, 5.35(%).

[0093] Referring to the above-mentioned similar synthesis method, the compounds shown in Table 1 below were prepared:

[0094] Table 1

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] Example 2

[0109] An organic electroluminescent device, such as Figure 1 and 2 As shown, the organic electroluminescent device 100 comprises 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, an electron transport layer 107, an electron injection layer 108, a cathode layer 109, and a capping layer 110 may be included on the cathode layer 109. Figure 2 The device 200 does not include a capping layer, but the device 200 has a first light-emitting layer and a second light-emitting layer, and the light emission peaks of the first light-emitting layer and the second light-emitting layer can be overlapping, cross-overlapping, or non-overlapping. In the corresponding layers of the device 200, materials similar to those described for the device 100 can be used.

[0110] A method for preparing an organic electroluminescent device according to this embodiment includes the following steps:

[0111] (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- 5Pa, and silver is evaporated on the above ITO film with a film thickness of An anode layer is obtained.

[0112] (2) On the above anode layer, a compound DNTPD was further evaporated as a hole injection layer, and the evaporated film thickness was NPD is continuously evaporated on the hole injection layer to form a hole transport layer with a thickness of

[0113] (3) A layer of compound HT202 is continuously evaporated on the hole transport layer as an electron blocking layer, and the evaporated film thickness is

[0114] (4) A layer of the compound containing two boron atoms as shown in Formula I of the present invention and A26 is continuously evaporated on the electron blocking layer as an organic light-emitting layer, wherein A26 is a main material and the compound containing two boron atoms as shown in Formula I of the present invention is a doping material, the doping concentration of the compound containing two boron atoms as shown in Formula I in A26 is 10%, and the evaporated film thickness is

[0115] (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 to ET205 is 1:1, and the evaporated film thickness is

[0116] (6) A layer of LiF compound is further evaporated on the electron transport layer as the electron injection layer of the device, and the evaporated film thickness is

[0117] (7) On the electron injection layer, magnesium and silver are deposited as the cathode layer of the element, wherein the mass ratio of magnesium to silver is 2:1 and the thickness of the deposited film is

[0118] (8) Compound HT038 was evaporated on the cathode layer as a capping layer, and the thickness of the evaporated film was

[0119] The structural formula of the compound used in this example is shown below:

[0120]

[0121] Comparative Example 1

[0122] An organic electroluminescent device was prepared according to the same steps as in Example 2, except that the compound BD022 was used instead of the compound containing two boron atoms of the present invention.

[0123] The structure of compound BD022 is:

[0124]

[0125] Test Example 1

[0126] The organic electroluminescent devices prepared in Example 2 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 light is on is the driving voltage, and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency; the LT95% life test is as follows: use a brightness meter at 1000cd / m 2 At 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 2 are relative data compared with Comparative Example 1. The results are shown in Table 2.

[0127] Table 2 Performance test results

[0128]

[0129]

[0130]

[0131]

[0132] The above experimental data show that the compounds of the present invention achieve excellent performances of lower driving voltage, higher luminous efficiency and longer life by adjusting the polarization direction of the BN rigid skeleton and maintaining a larger HOMO and LUMO orbital overlap. As a blue light doping material, a blue light organic electroluminescent element is obtained. Compared with the organic electroluminescent element using BD022 as a blue light doping material, the distinguishing feature is that the boron atoms of BD022 are connected to the same carbazole unit. Since the multiple resonance effect is too concentrated in the electron-withdrawing group part, the HOMO and LUMO of the molecule are separated, so the full height half maximum width (FWHM) of the luminescence peak is wide and the stability is poor. After adjusting the boron atom to be connected to the two para-nitrogen atom groups, the HOMO and LUMO orbital overlap increases, and the multiple resonance effect is dispersed in the central benzene ring, so it is excellent in molecular film formation and exciton transmission performance.

[0133] Possible industrial applications

[0134] The organic electroluminescent device of the present invention can be used in planar light emitters of wall-mounted televisions, flat-panel displays, lighting, etc., backlight sources of copiers, printers, liquid crystal displays, light sources of measuring instruments, etc., display panels, sign lights, etc.

[0135] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A compound containing two boron atoms, characterized in that The compound is selected from any one of the following structures: Among them, G 1 , G 2 , G 3 , G 4 Each independently selected from O, S or NR 9 ;X 1 , X 2 , X 3 , X 4 Each independently selected from a single bond, O, S, NR 9 or CR 9 R 10 ; Ar 1 ,Ar 2 are each independently selected from phenyl; R 1 ~R 8 At each occurrence, is independently selected from the group consisting of hydrogen, methyl, ethyl, isopropyl, tert-butyl, or fluoro; R 9 , R 10 At each occurrence, each is independently selected from the group consisting of methyl, ethyl, isopropyl or tert-butyl.

2. A compound containing two boron atoms, characterized in that The compound containing two boron atoms is selected from one of the compounds shown below:

3. An organic electroluminescent material, characterized in that: The compound comprising two boron atoms as described in any one of claims 1 or 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 compound containing two boron atoms as claimed in any one of claims 1 or 2.

5. The organic electroluminescent element according to claim 4, characterized in that: 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.

6. The organic electroluminescent element according to claim 4, characterized in that: The light-emitting layer further comprises a main material and a doping material, and the doping material comprises the compound containing two boron atoms as claimed in any one of claims 1 or 2.

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

50.

8. Use of the compound containing two boron atoms according to any one of claims 1 or 2 in an organic electroluminescent element.

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