An organic compound based on borazine and an organic electroluminescent device containing it.

Abstract

This invention discloses an organic compound based on borazine and an organic electroluminescent device containing it. The compound of this invention has a low refractive index in the visible light region and a refractive index of less than 1.6 in the blue light region. The low refractive index material of this invention, when combined with a high refractive index material to form a low-high double-layer capping layer, can effectively improve the light extraction efficiency of OLED devices and significantly reduce angle dependence after being applied to OLED devices, thereby improving the luminous efficiency of the devices and optimizing the apparent polarization performance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an organic compound based on borazine and its use as a capping layer in organic electroluminescent devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs), also known as organic electroluminescent devices, are a technology that uses organic materials to emit light through carrier injection and recombination under the influence of an electric field. They convert electrical energy into light energy through organic light-emitting materials. Theoretically, when both the anode and cathode are transparent electrodes, the light emitted from the light-emitting layer can propagate from either the anode or the cathode to the outside of the device. Therefore, based on the different light propagation paths, these devices can be classified as bottom-emitting devices and top-emitting devices.

[0003] In a bottom-emitting device, light propagates from the anode through the substrate to the outside of the device, while in a top-emitting device, light propagates through the cathode to the outside of the device. The different light emission methods of these two devices lead to vastly different applications. If a bottom-emitting device is used in an active matrix structure, its light emission path is organic layer-anode-TFT-substrate. The TFT is a mesh array switch deposited on the substrate. The presence of the TFT further reduces the aperture ratio of the device, causing the emitted light to be reflected and scattered at this point, preventing it from propagating to the outside of the device and severely impacting the display effect. In contrast, the top-emitting device emits light from the cathode side, bypassing the substrate and thus avoiding the TFT structure. This successfully avoids the reduced aperture ratio problem seen in bottom-emitting devices, resulting in a more detailed and clearer image with higher color vibrancy.

[0004] In top-emitting organic electroluminescent devices, the metal cathode layer and the bottom metal reflective layer form a resonant cavity (also called a microcavity), resulting in both constructive and destructive interference. As the viewing angle changes, the distance between the metal cathode layer and the bottom metal reflective layer (i.e., the cavity length of the microcavity) changes accordingly. This leads to significant differences in brightness and color observed at different viewing angles, severely impacting product performance.

[0005] In such light-emitting elements, when light emitted from the light-emitting layer is incident on other films at an angle greater than a certain value, total internal reflection will occur at the interface between the light-emitting layer and the other films. Therefore, only a portion of the emitted light can be utilized. In recent years, to improve light extraction efficiency and reduce color shift, light-emitting elements with a high-refractive-index "coating layer" placed on the outside of a semi-transparent electrode with a low refractive index have been proposed.

[0006] However, increasing the refractive index of the organic compounds used in the capping layer is very difficult. Therefore, in order to further improve the luminous efficiency of organic light-emitting elements without increasing the amount of material, this invention proposes and initially explores a double capping layer structure. Due to the refractive index difference between the high-refractive-index CPL and the low-refractive-index CPL, a portion of the light emitted from the light-emitting layer passes through the capping layer, while the other portion is reflected by the capping layer. Light is particularly reflected at the interface between the high-refractive-index CPL and the low-refractive-index CPL, and at the interface between the high-refractive-index CPL and the encapsulation structure. The light reflected by the capping layer is reflected again at the electrodes and is enhanced during repeated reflection. Therefore, repeated reflection can occur at the interface between the high-refractive-index CPL and the low-refractive-index CPL, and at the interface between the high-refractive-index CPL and the encapsulation structure, thereby recovering light lost due to reflection on the surface facing away from the OLED.

[0007] While Samsung's US20210159427A1 patent also uses a combination of low-refractive-index and high-refractive-index materials to form a double-layer capping layer, its low-refractive-index material is a coordination compound with poor coordination bond stability. This patent only describes its ability to improve device luminous efficiency, without mentioning its impact on device visual polarization. Similarly, Hodogaya's WO2022075396A1 patent also uses a combination of low-refractive-index and high-refractive-index materials to form a double-layer capping layer. However, its low-refractive-index material uses adamantane as the core, with aryl or heteroaryl groups connected to both sides via bridging groups such as amine, amide, ester, and ether. The disclosed structure has a low molecular weight, resulting in a low evaporation temperature (less than 200°C). This leads to unstable evaporation rates, easy material spraying, contamination of the evaporation equipment, and easy crystallization after coating, affecting device stability, especially at high temperatures. Furthermore, this patent only describes its ability to improve device luminous efficiency, without mentioning its impact on device visual polarization.

[0008] The current method of using capping layers to improve the performance of OLED devices mainly has the following problems:

[0009] 1. If the vapor deposition temperature is too high, the CPL material will decompose severely after prolonged vapor deposition.

[0010] 2. Under controlled low vapor deposition temperatures, the refractive index of organic CPL materials cannot be increased indefinitely.

[0011] 3. The light extraction efficiency is low, and when applied to OLED devices, the improvement in device luminous efficiency is limited.

[0012] 4. When applied to OLED devices, the color deviation of the device is not significantly improved, and the angle of the emitted light is highly dependent. As the angle changes, the brightness decreases, accompanied by changes in the emitted color.

[0013] To continuously improve the performance of OLED devices, innovation in OLED device structure and manufacturing processes is needed, as well as ongoing research and innovation in OLED optoelectronic functional materials to create higher-performance OLED functional materials. Therefore, finding suitable low-refractive-index materials paired with high-refractive-index materials as a double-layer capping layer for OLED devices to address the aforementioned issues is a long-standing need in this field. Summary of the Invention

[0014] To address the aforementioned problems in the prior art, this application provides an organic compound based on borazine and an organic electroluminescent device containing it. The compound of this invention has a low refractive index in the blue light region. The low refractive index compound of this invention can be used as a first capping layer in combination with a high refractive index second capping layer to improve light extraction efficiency and reduce angle dependence.

[0015] The present invention provides the following specific technical solution: an organic compound based on borazine, wherein the organic compound has a structure as shown in general formula (1):

[0016]

[0017] In general formula (1), L1, L2, L3, L4, L5, and L6 are each independently represented as a single bond, a substituted or unsubstituted C1-C20 branched or straight-chain alkylene group, a substituted or unsubstituted C1-C20 cycloalkylene group, a substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group containing one or more heteroatoms; L1, L2, L3, L4, L5, and L6 can be the same or different;

[0018] Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently represented by the structures shown in general formulas (2), (3), and (4); Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 may be the same or different.

[0019]

[0020]

[0021] In general formulas (2) and (3), Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z 10 , Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y 10 Each instance of the same or different characters independently represents CH, CR, or N.

[0022] Each instance of R, whether identical or different, independently represents a fluorine atom, a cyano group, a substituted or unsubstituted C1-C20 branched or straight-chain alkyl group, a substituted or unsubstituted C1-C20 cycloalkyl group, a substituted or unsubstituted C6-C50 aryl group, a substituted or unsubstituted C2-C50 heteroaryl group containing one or more heteroatoms, a substituted or unsubstituted C6-C50 arylamine group, or a substituted or unsubstituted C2-C50 heteroarylamine group containing one or more heteroatoms.

[0023] In general formulas (2) and (3), R1, R2, R3, R4, R5, R6, R7, R8, and R9 each independently represent a hydrogen atom, a fluorine atom, -CF3, and -CF2CF3; at least one of R1, R2, and R3 is not represented as a hydrogen atom; at least one of R4 to R9 is not represented as a hydrogen atom; R1, R2, R3, R4, R5, R6, R7, R8, and R9 may be the same or different.

[0024] In general formula (2), m = 1, 2, 3, 4 or 5;

[0025] In general formula (3), a and b are independently represented as 0, 1, 2, 3; a+b≥1; e and d are independently represented as 0, 1, 2, 3, 4, 5, e+d≥1;

[0026] In general formula (4), Ar7 and Ar8 are each independently represented as general formula (2), general formula (3), substituted or unsubstituted C1-C20 branched or straight-chain alkyl, substituted or unsubstituted C1-C20 cycloalkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl containing one or more heteroatoms; at least one of Ar7 and Ar8 is represented as general formula (2) or general formula (3);

[0027] The substituents of the "substituted or unsubstituted" group are selected from one or more of the following: protium atom, deuterium atom, tritium atom, halogen atom, cyano, trifluoromethyl, trifluoromethoxy, difluoromethyl, difluoromethoxy, fluoromethyl, fluoromethoxy, perfluoroethyl, perfluoroisopropyl, perfluorotert-butyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, cyclohexane, adamantane, cyclopentane, C6-C20 aryl, and C2-C20 heteroaryl containing one or more heteroatoms;

[0028] The heteroatoms in the C2-C50 heteroaryl, C2-C20 heteroaryl, C2-50 heteroarylamine, and C2-C50 heteroaryl groups are selected from nitrogen, oxygen, phosphorus, sulfur, or fluorine.

[0029] In a preferred embodiment, the structure of the organic compound is shown in general formula (5);

[0030]

[0031] Ar1, Ar2, L1, and L2 are defined as described above.

[0032] In a preferred embodiment, R1, R2, R3, R4, R5, R6, R7, R8, and R9 all represent fluorine atoms.

[0033] In a preferred embodiment, the structure of general formula (2) is as follows:

[0034] Any one of them;

[0035] The structure of the general formula (3) is as follows:

[0036] Any one of them;

[0037] The structure of the general formula (4) is as follows:

[0038] Any one of them;

[0039] m = 0, 1, 2, 3, 4 or 5;

[0040] a and b can be independently represented as 0, 1, 2 or 3;

[0041] e and d can be represented independently as 0, 1, 2, 3, 4 or 5.

[0042] In a preferred embodiment, the structure of general formula (2) is as follows:

[0043] Any one of them;

[0044] The structure of the general formula (3) is as follows:

[0045] Any one of them;

[0046] The structure of the general formula (4) is as follows:

[0047] Any one of them.

[0048] In a preferred embodiment, L1, L2, L3, L4, L5, and L6 represent substituted or unsubstituted methylene, substituted or unsubstituted ethylene, substituted or unsubstituted propylene, substituted or unsubstituted isopropylene, substituted or unsubstituted butylene, substituted or unsubstituted isobutylene, substituted or unsubstituted tert-butylene, substituted or unsubstituted pentylene, substituted or unsubstituted hexylene, substituted or unsubstituted cyclohexylene, substituted or unsubstituted adamantylene, substituted or unsubstituted cyclopropaneene, substituted or unsubstituted... Substituted cyclobutene, substituted or unsubstituted cyclopentene, substituted or unsubstituted cyclohexene, substituted or unsubstituted cyclooctene, substituted or unsubstituted cyclododecene, substituted or unsubstituted cyclooctadecene, substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted diphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted anthracene, substituted or unsubstituted phenanthylene, substituted or unsubstituted benzophenanthrene, substituted or unsubstituted pyridylene, etc. Substituted or unsubstituted carbazolyl, substituted or unsubstituted furanyl, substituted or unsubstituted naphthofuranyl, substituted or unsubstituted thiopheneyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted pyridazinyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluoreneyl, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted N-diphenylcarbazolyl, substituted or unsubstituted N-naphthylcarbazolyl, substituted or unsubstituted N-phenylcarbazolyl - One of the following: dibenzofuranylcarbazoyl, substituted or unsubstituted quinolineyl, substituted or unsubstituted isoquinolineyl, substituted or unsubstituted quinolineyl, substituted or unsubstituted quinoxalolineyl, substituted or unsubstituted quinoxalolineyl, substituted or unsubstituted naphthiolineyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted carbazolineyl, substituted or unsubstituted naphthiophenyl, substituted or unsubstituted benzooxazolyl, substituted or unsubstituted benzothiazoyl, substituted or unsubstituted naphthiofuranyl, or substituted or unsubstituted naphthiophenyl.

[0049] Ar7 and Ar8 represent substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted butyl, substituted or unsubstituted isobutyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted anthraquinone, substituted or unsubstituted phenanthyl, substituted or unsubstituted benzo[a]phenanthyl, substituted or unsubstituted pyridyl, substituted or unsubstituted carbazole, substituted or unsubstituted furanyl, substituted or unsubstituted naphthofuran[a]phenyl, substituted or unsubstituted thiopheneyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyrazinyl, and substituted or unsubstituted pyridazine. The following are general formulas (2) or (3): substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted N-phenylcarbazoyl, substituted or unsubstituted N-diphenylcarbazoyl, substituted or unsubstituted N-naphthylcarbazoyl, substituted or unsubstituted N-dibenzofuranylcarbazoyl, substituted or unsubstituted quinolinyl, substituted or unsubstituted isoquinolinyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted quinoxolinyl, substituted or unsubstituted quinoxolinyl, substituted or unsubstituted quinoxolinyl, substituted or unsubstituted naphthiophenyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted carbazolinyl, substituted or unsubstituted naphthidyl, substituted or unsubstituted benzooxazolyl, substituted or unsubstituted benzothiazoyl, substituted or unsubstituted naphthuryl, substituted or unsubstituted naphthiophenyl.

[0050] The R represents a hydrogen atom, a fluorine atom, trifluoromethyl, trifluoromethoxy, difluoromethyl, difluoromethoxy, fluoromethyl, fluoromethoxy, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted anthracene, substituted or unsubstituted phenanthyl, substituted or unsubstituted benzo[a]phenanthyl, substituted or unsubstituted pyridylene, substituted or unsubstituted carbazolyl, substituted or unsubstituted furanyl, substituted or unsubstituted naphthofuranophenyl, substituted or unsubstituted thiopheneyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyridylene. Azinyl, substituted or unsubstituted pyridazinyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted N-phenylcarbazoyl, substituted or unsubstituted N-diphenylcarbazoyl, substituted or unsubstituted N-naphthylcarbazoyl, substituted or unsubstituted N-dibenzofuranylcarbazoyl, substituted or unsubstituted quinolinyl, substituted or unsubstituted isoquinolinyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted quinoxalinyl, substituted or unsubstituted quinoxalinyl, substituted or unsubstituted cyclophosphine, substituted or unsubstituted benzothiazoyl, substituted or unsubstituted naphthioranyl, substituted or unsubstituted naphthioranyl;

[0051] The substituents in the "substituted or unsubstituted" designation are selected from one or more of the following: protium, deuterium, tritium, fluorine, cyano, trifluoromethyl, trifluoromethoxy, difluoromethyl, difluoromethoxy, fluoromethyl, fluoromethoxy, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, phenyl, naphthyl, biphenyl, pyridyl, and naphthidyl.

[0052] In a preferred embodiment, the organic compound has a specific structural formula that is any one of the following:

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] In a preferred embodiment, the refractive index of the organic compound under blue light at a wavelength of 460 nm is in the range of 1.4-1.7, preferably 1.4-1.6.

[0074] The present invention also provides an organic electroluminescent device, the organic electroluminescent device comprising:

[0075] Substrate layer;

[0076] A first electrode is located on the substrate;

[0077] An organic light-emitting functional layer is disposed on the first electrode;

[0078] A second electrode, which is situated on the organic light-emitting functional layer; and

[0079] A capping layer is applied over the second electrode;

[0080] The coating layer contains one or more of the borazine-based organic compounds.

[0081] In a preferred embodiment, the covering layer includes a first covering layer and a second covering layer.

[0082] The first covering layer is on top of the second electrode;

[0083] The second cover layer is on top of the first cover layer;

[0084] The first covering layer is characterized in that it comprises one or more of the organic compounds based on borazine.

[0085] In a preferred embodiment, the refractive index of the first cover layer material is less than the refractive index of the second cover layer material;

[0086] Preferably, the refractive index of the first cover layer material at a wavelength of 460 nm is less than or equal to 1.65;

[0087] Preferably, the refractive index of the second capping layer material at a wavelength of 460 nm is greater than or equal to 1.85;

[0088] Preferably, the difference in refractive index between the second capping layer material and the first capping layer material at a wavelength of 460 nm is greater than or equal to 0.3;

[0089] Preferably, the band gap Eg of the first cover layer material is greater than 3.0 eV, more preferably greater than 3.5 eV;

[0090] Preferably, the difference in refractive index between the first capping layer material and the wavelength at 460 nm and 620 nm is ≤0.3.

[0091] In a preferred embodiment, the total thickness of the capping layer is 15-300 nm, more preferably 30-200 nm, even more preferably 40 nm-100 nm, and most preferably 50-80 nm; the thickness of the first capping layer is 1-150 nm, preferably 5-100 nm, and more preferably 10-50 nm; the thickness of the second capping layer is 1-150 nm, preferably 10-100 nm, and more preferably 20-80 nm.

[0092] Technical effects of the invention:

[0093] The compounds of this invention have a refractive index below 1.6 in the blue light region. These low-refractive-index compounds can be used as a first capping layer in combination with a high-refractive-index second capping layer to improve light extraction efficiency and reduce angle dependence. Attached Figure Description

[0094] Figure 1 This is a schematic cross-sectional structure diagram of an application example of the compound of the present invention (top-emitting organic electroluminescent device).

[0095] In this design, 100 is the substrate, 200 is the first electrode, 300 is the organic light-emitting functional layer, 400 is the second electrode, and 500 is the capping layer.

[0096] Figure 2 for Figure 1 A cross-sectional schematic diagram of the organic light-emitting functional layer 300 of the top-emitting organic electroluminescent device, wherein 310 (HIL) is the hole injection layer, 320 (HTL) is the hole transport layer, 330 (EBL) is the electron blocking layer, 340 (EML) is the light-emitting layer, 350 (HBL) is the hole blocking layer, 360 (ETL) is the electron transport layer, and 370 (EIL) is the electron injection layer.

[0097] Figure 3 for Figure 1 A cross-sectional structural diagram of the middle capping layer 500, wherein 510 is the first capping layer with low refractive index and 520 is the second capping layer with high refractive index. Detailed Implementation

[0098] Throughout this specification, unless explicitly stated otherwise, the term "including" any component will be understood to imply the inclusion of other components, not to exclude any other components. Furthermore, it should be understood that throughout this specification, when an element such as a layer, film, region, or substrate is referred to as being "on" or "above" another element, it may be "directly on" the other element, or there may be intermediate elements present. Additionally, "on" or "above" means located above the target portion, and not necessarily above it in the direction of gravity.

[0099] In this paper, "n@460nm" refers to the refractive index of the material relative to vacuum for blue light at a wavelength of 460nm; "n@525nm" refers to the refractive index of the material relative to vacuum for green light at a wavelength of 525nm; "n@620nm" refers to the refractive index of the material relative to vacuum for red light at a wavelength of 620nm; and "k@380nm" refers to the extinction coefficient of the material relative to vacuum for a wavelength of 380nm.

[0100] In this document, C6-C50 aryl refers to a monovalent group comprising a carbocyclic aromatic system having 6 to 50 carbon atoms as cyclic atoms. Non-limiting examples of C6-C50 aryl groups may include phenyl, biphenyl, phenanthryl, triphenyl, naphthyl, phenanthryl, benzo[a]phenanthryl, benzyl, anthracene, 9,10-benzo[a]phenanthryl, fused tetraphenyl, pyrene, diphenyl, p-triphenyl, meta-triphenyl, etc. Aryl, triphenylene, peryl, indene, triphenylene, fenenyl, fluorenyl, dimethylfluorenyl, diphenylfluorenyl, benzodimethylfluorenyl, etc. When the C6-C50 aryl group includes two or more rings, these rings can fused together.

[0101] In this document, non-limiting examples of C2-C50 heteroaryl groups may include furanyl, thiopheneyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl. 1,3,4-Thiadiazolyl, 1,2,5-Thiadiazolyl, Tetrazolyl, Pyridyl, Pyrimidinyl, Pyridazinyl, 1,2,3-Triazinyl, 1,2,4-Triazinyl, 1,3,5-Triazinyl, Benzofuranyl, Benzoisofuranyl, Benzothiophenyl, Benzoisothiophenyl, Indoleyl, Isoyndoleyl, Inzazoleyl, Benzimidazolyl, Benzooxazolyl, Benzoisooxazolyl, Benzothiophenyl Azolyl, 2,1,3-benzoxadiazole, quinolinyl, isoquinolinyl, terolinyl, phthalazinyl, quinazolinyl, quinolinyl, naphridinyl, benzotriazinyl, benzoxazinyl, purine, pteridinyl, indazinyl, benzothiazinyl, acridineyl, benazinyl, benazinyl, benazinyl, dibenzofuranyl, dibenzothiopheneyl, carbazole, naphridinyl, quinolinyl, isoquinolinyl, indole[1,2] -f] phenanthridine, imidazo[2,1-a]isoquinolinyl, imidazo[1,2-a]quinolinyl, benzo[4,5]imidazo[1,2-a]pyridyl, imidazo[1,2-a]pyridyl, benzofuran[3,2-c]quinolinyl, naphtho[1,2-b]benzofuranyl, naphtho[2,3-b]benzofuranyl, etc., also including aromatic composite groups with heteroatoms, etc. When C2-C 50 When a heteroaryl group comprises two or more rings, these rings can fused together.

[0102] In this article, C6-C is used 20 An aryl group is a monovalent group in a carbocyclic aromatic system comprising 6 to 20 carbon atoms as cyclic atoms. (C6-C) 20 Non-limiting examples of aryl groups may include phenyl, biphenyl, phenanthryl, triphenyl, naphthyl, phenanthryl, benzo[a]phenanthryl, benzyl, anthracene, 9,10-benzo[a]phenanthryl, fused tetraphenyl, pyrene, diphenyl, p-triphenyl, meta-triphenyl, etc. It includes compounds such as methyl, triphenyl, peryl, indene, triphenyl, fumoni, fluorenyl, dimethylfluorenyl, diphenylfluorenyl, benzodimethylfluorenyl, etc.

[0103] The C2-C used in this article 20 A heteroaryl group is a monovalent group comprising a carbocyclic aromatic system having at least one heteroatom selected from N, O, P, and S as the cyclic atom and 2 to 20 carbon atoms. (C2-C) 20Non-limiting examples of heteroaryl groups may include pyridyl, oxadiazolyl, triazine, pyrimidinyl, furanyl, dibenzofuranyl, dibenzothiophenyl, benzooxazolyl, bisbenzooxazolyl, carbazoyl, N-phenylcarbazoyl, quinolinyl, isoquinolinyl, naphthofuranyl, and phenyl-substituted naphthofuranyl.

[0104] In this article, C6-C 50 Aryl groups refer to phenylene, naphthylene, anthraceneylene, fluoreneylene, dimethylfluoreneylene, diphenylfluoreneylene, spirofluoreneylene, phenanthreneylene, tetraphenylene, pyreneylene, biphenylene, para-triphenylene, meta-triphenylene, and so on. It can be alkyl, triphenylene, perylene, indene, but is not limited to these.

[0105] In this article, C2-C 50 The term "heteroaryl" refers to fused rings of the following groups: furanyl, thiopheneyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiazolyl, pyridinyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuranyl, benzothiopheneyl, benzoimidazolyl, indolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinolinyl, naphridinyl, benzooxazinyl, benzothiazinyl, acridineyl, phenazinyl, phenthiazinyl, phenoxazinyl, fenenyl, dibenzofuranyl, dibenzothiopheneyl, carbazolyl, or combinations thereof, but is not limited to these.

[0106] The halogen atoms mentioned in this invention refer to fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0107] In this article, C1-C20 branched or straight-chain alkylene groups are: methylene, ethylene, propylene, isopropylene, butylene, isobutylene, tert-butylene, pentylene, or hexylene;

[0108] In this article, C1-C20 cycloalkylene compounds are: cyclohexylene, adamantylene, cyclopropane, cyclobutane, cyclopentane, cyclohexylene, cyclooctane, cyclododecane, or cyclooctadecane.

[0109] In this article, C1-C20 branched or straight-chain alkyl groups are: methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, sec-butyl, neopentyl, n-pentyl, isopentyl, octyl, heptyl, n-decyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl or 1-butylpentyl;

[0110] In this article, C1-C20 cycloalkyl groups are: cyclohexyl, adamantyl, cyclopropane, cyclobutane, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, or cyclooctadecyl.

[0111] In this document, the term "amine" refers to a primary, secondary, or tertiary amine group having a specified number of carbon atoms in each case (e.g., 1 to 100, preferably 1 to 50, more preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 12, and more preferably 1 to 6).

[0112] In this document, the term "arylamine" refers to a primary, secondary, or tertiary amine group substituted with an aryl group. The term "heteroarylamine" refers to a primary, secondary, or tertiary amine group substituted with a heteroaryl group.

[0113] "Aromaticamine" refers to a divalent group in an aryl amine system, while "heteroarylamine" refers to a divalent group in a heteroaryl amine system.

[0114] Organic electroluminescent devices

[0115] The compounds of this invention are particularly suitable for use in vapor deposition and for improving light extraction efficiency, and can improve the stability of the production process, resulting in devices or components with high yield and high visible light extraction efficiency.

[0116] The organic electroluminescent device of the present invention includes:

[0117] Substrate layer;

[0118] A first electrode, which is on the substrate layer;

[0119] An organic light-emitting functional layer is disposed on the first electrode;

[0120] A second electrode, which is situated on the organic light-emitting functional layer; and

[0121] A capping layer is applied over the second electrode;

[0122] The coating layer contains one or more of the borazine-based organic compounds.

[0123] In one embodiment of the present invention, the refractive index of the first capping layer is less than the refractive index of the second capping layer; the refractive index of the first capping layer at 460 nm is less than or equal to 1.65, preferably less than or equal to 1.60, preferably less than or equal to 1.55; preferably less than or equal to 1.50; the refractive index of the first capping layer at 525 nm is less than or equal to 1.65, preferably less than or equal to 1.60, preferably less than or equal to 1.55; preferably less than or equal to 1.50; the refractive index of the first capping layer at 620 nm is less than or equal to 1.65, preferably less than or equal to 1.60, preferably less than or equal to 1.55; preferably less than... The refractive index of the second capping layer at 460nm is greater than or equal to 1.85, preferably greater than or equal to 1.9, preferably greater than or equal to 2.0, preferably greater than or equal to 2.1, preferably greater than or equal to 2.2; more preferably greater than or equal to 2.3; the refractive index of the second capping layer at 525nm is greater than or equal to 1.85, preferably greater than or equal to 1.9, preferably greater than or equal to 2.0, preferably greater than or equal to 2.1, more preferably greater than or equal to 2.2; the refractive index of the second capping layer at 620nm is greater than or equal to 1.8, preferably greater than or equal to 1.9, preferably greater than or equal to 2.0, more preferably greater than or equal to 2.1.

[0124] In one embodiment of the present invention, the difference in refractive index @460nm between the first capping layer and the second capping layer is greater than or equal to 0.3; preferably greater than or equal to 0.4; preferably greater than or equal to 0.5; preferably greater than or equal to 0.6; preferably greater than or equal to 0.7; more preferably greater than or equal to 0.8.

[0125] In a preferred embodiment of the present invention, an organic electroluminescent device is provided, comprising a substrate, an anode, a cathode, an organic light-emitting functional layer, and a capping layer. The organic light-emitting functional layer may include a light-emitting layer, a hole transport layer, a hole injection layer, an electron blocking layer, an electron transport layer, an electron injection layer, etc., or may only include a light-emitting layer and one or more other layers. The capping layer is composed of one or more organic compounds based on borazine as the core, as shown in the above general formula (1). Optionally, a protective layer and an encapsulation layer are further provided above the capping layer.

[0126] like Figure 1 As shown, substrate 100 can be any substrate typically used in organic light-emitting devices. It can be a glass or transparent plastic substrate, an opaque material such as silicon or stainless steel, or a flexible PI film. Different substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and water resistance, and their applications vary depending on their properties.

[0127] A first electrode 200 is formed on the substrate 100. The first electrode 200 can be either a cathode or an anode. Here, the first electrode 200 can be simply a reflective electrode, such as a reflective film formed of silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr) or their alloys, or it can be an electrode composed of a reflective film and a transparent or semi-transparent electrode, for example, a transparent or semi-transparent electrode layer with high work function formed on the reflective film. The transparent or semi-transparent electrode layer can be formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), aluminum zinc oxide (AZO), indium gallium oxide (IGO), indium oxide (In2O3), or tin oxide (SnO2); it can also be composed of a combination of metal and oxide, such as ITO / Ag / ITO, IGO / Al / IGO, or AZO / Ag / AZO.

[0128] The first electrode 200 can be formed by methods such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation or chemical vapor deposition (CVD), preferably by sputtering.

[0129] The thickness of the first electrode layer 200 depends on the material used, and is typically 5nm-1μm, preferably 10nm-1μm, more preferably 10nm-500nm, particularly preferably 10nm-300nm, and most preferably 10nm-200nm.

[0130] like Figure 2 As shown, the organic light-emitting functional layer 300 may include a light-emitting layer 340 (EML), and if the first electrode 200 is an anode, a hole transport region may be formed between the EML and the first electrode 200, and an electron transport region may be formed between the EML and the second electrode layer 400; if the first electrode 200 is a cathode, an electron transport region may be formed between the EML and the first electrode 200, and a hole transport region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL). Therefore, the organic light-emitting functional layer 300 includes a light-emitting layer and a combination of at least two of the following layers: a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0131] The thickness of the organic light-emitting functional layer 300 is 50nm-1000nm.

[0132] As for the materials used in the hole injection layer, hole transport layer, and electron blocking layer (HIL310, HTL320, EBL330), any material can be selected from known materials used in OLED devices.

[0133] At least one layer of HIL310 and HTL320 may further include a charge-generating material for improving conductivity. The charge-generating material may be a p-dopant. Non-limiting compounds of p-dopants include: quinone derivatives, such as tetracyanoquinone dimethyl (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinone dimethyl (F4-TCNQ); or hexaazatriphenyl derivatives, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenyl (HAT-CN); or cyclopropane derivatives, such as 4,4',4”-((1E,1'E,1”E)-cyclopropane-1,2,3-trimethylenetris(cyanoformyl))tris(2,3,5,6-tetrafluorobenzyl); or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0134] In EBL330, the triplet (T1) energy level of the material is required to be higher than the T1 energy level of the host material in the emissive layer 340, which can effectively block energy loss from the emissive layer material. The HOMO energy level of the EBL330 material is between the HOMO energy level of the HTL320 material and the HOMO energy level of the host material in the emissive layer 340, which facilitates hole injection from the positive electrode into the emissive layer. At the same time, the EBL330 material is required to have high hole mobility, which is beneficial for hole transport and reduces the power consumption of the device. The LUMO energy level of the EBL330 material is higher than the LUMO energy level of the host material in the emissive layer 340, which acts as an electron blocker, that is, the EBL330 material is required to have a wide bandgap (Eg). EBL330 materials that meet the above conditions can be triarylamine derivatives, fluorene derivatives, spirofluorene derivatives, dibenzofuran derivatives, carbazole derivatives, etc. Preferred are triarylamine derivatives, such as N4,N4-bis([1,1'-biphenyl]-4-yl)-N4'-phenylN4'-[1,1':4',1”-terphenyl]-4-yl-[1,1'-biphenyl]-4,4'-diamine; spirofluorene derivatives, such as N-([1,1'-diphenyl]-4-yl)-N-(9,9-dimethyl-9H-furan-2-yl)-9,9'-spirodifluorene-2-amine; dibenzofuran derivatives, such as N,N-bis([1,1'-biphenyl]-4-yl)-3'-(dibenzo[b,d]furan-4-yl)-[1,1'-biphenyl]-4-amine, but not limited thereto.

[0135] To obtain a high-efficiency OLED device, its light-emitting layer 340 can use the same doping material or multiple doping materials. The doping materials can be simple fluorescent materials, delayed fluorescence (TADF) materials, or phosphorescent materials, or a combination of different fluorescent materials, TADF materials, and phosphorescent materials. The light-emitting layer 340 can be a single light-emitting layer material or a composite light-emitting layer material stacked laterally or vertically. The light-emitting layer 340 constituting the above-mentioned OLED light emitter can be selected from the following various structures:

[0136] (1) Single organic light-emitting layer material;

[0137] (2) Any combination of blue organic light-emitting layer material and green, yellow or red light-emitting layer material, in no particular order;

[0138] (3) Any two combinations of blue organic light-emitting layer material and green, yellow or red light-emitting layer material, without regard to the order of their arrangement;

[0139] (4) Blue organic light-emitting layer material, green organic light-emitting layer material, and red organic light-emitting layer material are arranged horizontally.

[0140] In order to regulate the effective binding of charge carriers in the light-emitting layer, the film thickness of the light-emitting layer 340 constituting the OLED light emitter can be adjusted arbitrarily as needed, or light-emitting layers of different colors can be stacked and combined alternately as needed, and charge blocking layers with different functions can be added to the organic layers adjacent to the light-emitting layer.

[0141] The host material of the light-emitting layer constituting the aforementioned OLED light emitter not only needs to possess bipolar charge transport characteristics, but also needs to have an appropriate energy level to effectively transfer the excitation energy generated by electron-hole recombination to the guest light-emitting material, i.e., the doped material. Examples of such materials include stilbene arylene derivatives, stilbene derivatives, carbazole derivatives, triarylamine derivatives, anthracene derivatives, pyrene derivatives, triazine derivatives, xanthone derivatives, triphenylene derivatives, triazine derivatives, hexabenzobenzene derivatives, or bis(2-methyl-8-quinoline)(p-phenylphenol)aluminum (BAlq).

[0142] The materials used to form the hole blocking layer 350 and the electron transport layer 360 of the OLED device can be any material selected from those used in OLEDs that have electron transport properties. Examples of such materials include 1,3-bis[5'-(p-tert-butylphenyl)-1,3,4-oxadiazole-2'-yl]benzene, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole and other oxadiazole derivatives, 3-(4'-tert-butylphenyl)-4-phenyl-5-(4”-biphenyl)-1,2,4-triazole and other triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, dibenzoquinone derivatives, nitro-substituted linone derivatives, thiam dioxide derivatives, anthraquinone dimethane derivatives, thiam dioxide derivatives, naphthylperylene and other heterocyclic tetrahydric anhydrides, carbodiimide, lin derivatives, anthraquinone dimethane derivatives, anthrone derivatives, stilbene pyrazine derivatives, silyrocyclopentadiene derivatives, diazonium phenanthrene derivatives, or imidazopyridine derivatives, etc.

[0143] A second electrode 400 is formed on the organic light-emitting functional layer 300. The second electrode layer can be a cathode or an anode, and can be a transparent electrode or a semi-transparent electrode. The second electrode 400 can be made of lithium, calcium, lithium fluoride / calcium, lithium fluoride / aluminum, aluminum, silver, magnesium, or alloys thereof to form a thin film with low work function. Further, the second electrode layer 400 can be made of an alloy including silver and at least one metal, said at least one metal including aluminum, platinum, ytterbium, chromium, or magnesium. Furthermore, the weight ratio of Ag in the alloy can be the same as, greater than, or less than the weight ratio of the other metals. For example, the second electrode layer 400 can be formed of an Ag-Mg alloy, wherein the mass ratio of Ag to Mg can be 90:10 to 10:90. Alternatively, the second electrode layer 400 can be formed of an alloy including at least one metal such as silver, gold, platinum, copper, nickel, or tungsten and at least one metal such as ytterbium, indium, magnesium, or chromium. These metal films can be made into transparent or semi-transparent electrodes by adjusting the film thickness. Therefore, the light generated by the organic light-emitting functional layer 300 can be emitted through the second electrode layer 400. Furthermore, the thickness of the second electrode layer 400 can be 5-20 nm.

[0144] A cover layer 500 is formed on the second electrode layer 400, the cover layer including a first cover layer 510 and a second cover layer 520.

[0145] The material used in the first coating layer is an organic compound based on borazine, as shown in the above general formula (1).

[0146] The second cover layer material can be exemplified by the following structure:

[0147]

[0148] The total film thickness of the cover layer of the present invention is 15-300nm, preferably 30-200nm, more preferably 40nm-100nm, and most preferably 50-80nm; the film thickness of the first cover layer is 1-150nm, preferably 5-100nm, and more preferably 10-50nm; the film thickness of the second cover layer is 1-150nm, preferably 10-100nm, and more preferably 20-80nm; the film thickness of the second cover layer and the film thickness of the first cover layer may be the same or different.

[0149] refer to Figure 1 The organic electroluminescent device of the present invention includes a substrate layer 100, a first electrode layer 200, an organic light-emitting functional layer 300, a second electrode layer 400, and a capping layer 500.

[0150] A barrier layer (which may be composed of inorganic and / or organic materials and is used to prevent foreign matter from penetrating the substrate and device) and a wiring layer (which may include driving TFTs, capacitors, wires and low-temperature polysilicon LTPS) can be formed on the substrate layer using known methods.

[0151] In one specific embodiment, the first electrode 200 can be a reflective electrode and the second electrode 400 is a transparent or translucent electrode. Therefore, light generated by the organic light-emitting functional layer 300 can be directly emitted from the second electrode 400, or it can be reflected by the first electrode 200 towards the second electrode 400 before being emitted. The first electrode 200 can be prepared, for example, by vapor deposition or sputtering. The second electrode 400 can be prepared, for example, by vacuum vapor deposition.

[0152] The organic light-emitting functional layer 300 may include a light-emitting layer 340 (EML), and a hole transport region may be formed between the EML and the first electrode 200, and an electron transport region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL).

[0153] The organic light-emitting functional layer 300 can be composed of small-molecule organic materials or polymer materials, and the organic light-emitting functional layer 300 can be prepared by a variety of methods, such as vacuum evaporation, solution spin coating, screen printing, and inkjet printing.

[0154] The capping layer 500 may be composed of the organic compound based on the heteroarylamine structure, and the capping layer 500 may be prepared by a variety of methods, such as vacuum evaporation, solution spin coating, screen printing, and inkjet printing.

[0155] A protective layer is provided on the capping layer 500. The protective layer contains lithium fluoride (LiF). The thickness of the protective layer depends on the material used, typically 20-400 nm, preferably 30-200 nm, and more preferably 40-100 nm.

[0156] An encapsulation layer is disposed on the protective layer. The encapsulation layer is a protective structure that prevents external substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. It is a multilayer thin film covering the entire surface of the organic layer, the capping layer, and the protective layer. It includes a first encapsulation layer on the protective layer, a second encapsulation layer on the first encapsulation layer, and a third encapsulation layer on the second encapsulation layer; the first encapsulation layer is an inorganic layer; the second encapsulation layer is an organic layer; and the third encapsulation layer is an inorganic layer containing materials selected from Al₂O₃ and SiO₂. x N y TiO2, SiO x and SiN x At least one of the groups, wherein x and y are the same or different, and x and y are independently greater than 0 and less than 10, preferably greater than 0 and less than 5, and most preferably greater than 0 and less than 3. The inorganic layer is prepared by chemical vapor deposition (CVD).

[0157] As the encapsulation layer organic material for the organic light-emitting device of the present invention, organic encapsulation layer organic materials known in the prior art for organic light-emitting devices can be used. In a preferred embodiment of the present invention, the encapsulation layer organic material used is polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polystyrene (PS), polymer derivatives having phenol groups, acrylic-based polymers, imide-based polymers, arylether-based polymers, amide-based polymers, fluorine-based polymers, p-xylene-based polymers, vinyl alcohol-based polymers, or mixtures thereof.

[0158] The organic material of the encapsulation layer is thick enough to cover the inorganic encapsulation layer, and the organic material of the encapsulation layer is cured into a polymer by UV curing.

[0159] According to the present invention, the organic electroluminescent device is preferably a top-emitting organic electroluminescent device, which includes, after preparing an anode, a cathode and an organic light-emitting functional layer, depositing an organic compound based on borazine as the core of the present invention as a capping layer on the light-emitting side, in order to improve light extraction efficiency and visual deviation problem.

[0160] The viewing bias problem mentioned in this article refers to the gradual change in the emitted color of a device when viewed from different angles. In this paper, improving viewing bias and reducing angle dependence is reflected in a significant decrease in the trend of color change with changing viewing angles; ideally, the emitted color does not change. This can be measured by the parameter JNCD (Just Noticeable Color Difference), which is the most noticeable color difference perceptible to the human eye. The smaller the JNCD value, the more significant the improvement in viewing bias.

[0161] Furthermore, the OLED device of the present invention can be used in OLED lighting and display devices.

[0162] Preferably, the OLED devices prepared by the present invention are used in fields such as smartphones, tablets, smart wearable devices, large-size applications such as televisions, VR, micro-displays, and automotive central control screens or automotive taillights.

[0163] Example

[0164] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0165] I. Synthesis of Intermediate 1:

[0166]

[0167] 3-Bromo-5-iodotrifluorotoluene (10 mmol), 2,4-bis(trifluoromethylphenylboronic acid) (10 mmol), potassium carbonate (1.2 mmol), and tetrakis(triphenylphosphine)palladium (0.1 mmol) were separately charged into a flask equipped with a reflux condenser under nitrogen protection. The reactants were dissolved in 60 mL of a toluene / ethanol / water mixture (v / v = 15:7:2) and stirred at 100 °C for 20 h. The reaction was confirmed to be complete by TLC. After cooling to room temperature, 20 mL of water was added, the aqueous phase was extracted with diethyl ether, the organic phase was dried over MgSO4, and the solvent was evaporated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane:CH2Cl2 = 5:1) to give intermediate 1. LC-MS: Measured value: 436.79 ([M+H]+), accurate mass: 435.95.

[0168] II. Synthesis of Intermediate 2:

[0169]

[0170] Intermediate 2 was prepared using the same method as intermediate 1, except that 2,4-bis(trifluoromethyl)phenylboronic acid was replaced with 3,5-bis(trifluoromethyl)phenylboronic acid. LC-MS: Measured value: 436.62 ([M+H]+), exact mass: 435.95.

[0171] III. Synthesis of Intermediate 3:

[0172]

[0173] Under nitrogen protection, di[3,5-bis(trifluoromethyl)phenyl]amine (10 mmol), 3,5-dibromotrifluorotoluene (10 mmol), and 200 mL of toluene were added to a three-necked flask and stirred. Then, Pd2(dba)3 (0.22 mmol), 2-dicyclohexylphospho-2',4',6'-triisodimethylbiphenyl (0.22 mmol), and sodium tert-butoxide (30 mmol) were added. The mixture was heated to reflux for 10 h, cooled to room temperature, and rotary evaporated. The solution was washed three times with water (3 x 20 mL) and methanol (3 x 20 mL) to obtain intermediate 3. LC-MS: Measured value: 663.39 ([M+H]+), accurate mass: 662.97.

[0174] IV. Synthesis of Intermediate 4:

[0175]

[0176] Under a nitrogen atmosphere at 0°C, 1-bromoadamantane (0.5 g, 0.23 mmol) in anhydrous diethyl ether (1 ml) was slowly added to anhydrous diethyl ether (1 ml) containing magnesium metal (0.2 g, 8.2 mmol) in a pressure tube. The diethyl ether was kept at a gentle boil until the magnesium shavings disappeared, at which point the reaction was stopped, and the corresponding adamantane Grignard reagent was obtained.

[0177] 3,5-Dibromotrifluorotoluene (0.69 g, 0.23 mmol) was added dropwise to the Grignard reagent with stirring over 10 minutes. After stirring, the mixture was slowly heated to 100 °C and maintained for 2 hours. Then, it was cooled to -78 °C in a dry ice-acetone bath and carefully opened. The reaction mixture was transferred to a separatory funnel containing 20 g of ice and extracted with diethyl ether (3 × 20 mL). The combined ether extracts were dried over anhydrous magnesium sulfate and evaporated under vacuum to give intermediate 4. LC-MS: Analytical value: 359.26 ([M+H]+), accurate mass: 358.05.

[0178] Preparation of the compounds of the present invention

[0179] Example 1: Synthesis of Compound 1:

[0180]

[0181] In a dry 25 mL Schlenk flask, 8 mL of a toluene solution of p-trifluoromethylaniline (645 mg, 4 mmol) was added, and the mixture was cooled to -5 °C. 5.2 mL of a 1 M toluene solution of BCl3 was added dropwise, and the mixture was refluxed for 19 h. Excess hydrochloric acid was removed by three freeze-thaw cycles at 0 °C. The resulting mixture was added at -78 °C to 10 mL of anhydrous tetrahydrofuran solution of 3,5-bis(trifluoromethyl)bromobenzene (1.29 g, 4.4 mmol) and t-BuLi (1.36 M heptane solution, 3.23 mL, 4.4 mmol), and the mixture was heated to 0 °C and stirred for 1 h. The chloroborazole intermediate was added dropwise to a solution containing an organometallic compound, and the reaction was allowed to proceed at room temperature for 24 h. The reaction mixture was diluted with 20 mL of water, extracted with ethyl acetate (3 x 20 mL), and the combined organic phase was dried over MgSO4 and the solvent was removed under reduced pressure. The crude solid was purified by silica gel chromatography (3:2 hexane / toluene; Rf = 0.25). The target product compound 1 was obtained.

[0182] The compounds in the following synthetic examples 2 to 17 were prepared using the same method as in synthetic example 1, except that different starting materials M, N, and intermediate A were used. The starting materials and intermediates used in the synthesis process are shown in Table 1 below.

[0183] Table 1

[0184]

[0185]

[0186]

[0187]

[0188]

[0189] IV. Determination of the physical properties of compounds

[0190] Measurement method: The refractive index n and extinction coefficient k (glass substrate isotropic) were measured by an ellipsometer (JAWoollam Co., USA, model: ALPHA-SE) (tested in an atmospheric environment); the test results are shown in Table 2 below.

[0191] Table 2

[0192] compound Refractive index n@460nm compound Refractive index n@460nm Compound 1 1.459 Compound 189 1.529 Compound 15 1.403 Compound 217 1.481 Compound 28 1.411 Compound 253 1.586 Compound 39 1.532 Compound 260 1.411 Compound 46 1.528 Compound 272 1.559 Compound 82 1.474 Compound 276 1.566 Compound 106 1.447 Compound 284 1.421 Compound 131 1.515 Compound CP-H1 2.198 Compound 148 1.557 Compound CP-H12 2.243 Compound 172 1.489

[0193] As can be seen from the data in Table 2 above, the refractive index of the compound of the present invention in the blue light region is less than 1.6; even less than 1.5.

[0194] V Device Examples

[0195] The following device examples further illustrate the beneficial technical effects of applying the compounds of the present invention as a capping layer in OLED devices.

[0196] 1. Materials, equipment, and testing methods used in the embodiments

[0197] Materials sourced from commercial purchases or synthesized independently by referencing existing technical literature.

[0198] The molecular structural formulas of the relevant materials are shown below:

[0199]

[0200]

[0201] equipment:

[0202] Vacuum Evaporation Equipment: Choshu Sangyo 200*200mm Vacuum Evaporation Equipment (Japan)

[0203] Test method:

[0204] Measurement of current efficiency, CIEx, CIEy, and perceptible color difference (JNCD):

[0205] Using an IVL (current-voltage-luminance) testing system (Suzhou Fostec Scientific Instruments Co., Ltd.), and selecting software EILV20060707, the OLED devices in the following device examples and comparative examples were tested. Data such as IVL characteristic curves, efficiency versus current density curves, and color coordinate positions were obtained. The tests must be conducted in a dark environment under a masking device. (At @10mA / cm) 2 The data under the specified conditions shall prevail (i.e., the test current density reaches 10 mA / cm²). 2 (corresponding performance values ​​at that time).

[0206] Structure and fabrication method of device embodiment 1:

[0207] Structure of Device Example 1: Substrate layer 100 / First electrode (anode) layer 200 (Ag (100nm)) / Hole injection layer 310 (HT-1:P-1 = 97:3 mass ratio, thickness 10nm) / Hole transport layer 320 (HT-1, thickness 117nm) / Electron blocking layer 330 (EB-1, thickness 10nm) / Light emitting layer 340 (BH-1:BD-1 = 97:3 mass ratio, thickness 20nm) / Hole blocking layer 350 (HB-1, thickness 8nm) / Electron transport layer 360 (ET-1:LiQ = 1:1 mass ratio, thickness 30nm) / Electron injection layer 370 (LiF, thickness 1nm) / Second electrode (cathode) layer 400 (Mg:Ag = 1:9 mass ratio, thickness 16nm) / First capping layer 510 (Compound 1 of the present invention, thickness 15nm) / Second capping layer 520 (CP-H1, thickness 50nm).

[0208] Fabrication method of device embodiment 1: The transparent substrate layer 100 is transparent glass, and the first electrode (anode) layer 200 is Ag (100nm). The first electrode (anode) layer 200 is washed, i.e., it is successively washed with alkali, washed with pure water, dried, and then washed with ultraviolet light-ozone to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, HT-1 and P-1 with a thickness of 10nm are deposited as hole injection layer 310 using a vacuum evaporation apparatus, with a mass ratio of HT-1 to P-1 of 97:3. Then, HT-1 with a thickness of 117nm is deposited as hole transport layer 320. Subsequently, EB-1 with a thickness of 10nm is deposited as electron blocking layer 330. After the above electron blocking material is deposited, the light-emitting layer 340 of the OLED light-emitting device is fabricated. Its structure includes BH-1 as the main material and BD-1 as the dopant material, with a doping ratio of 3% by weight, and the thickness of the light-emitting layer is 20nm. Following the aforementioned light-emitting layer 340, HB-1 is deposited to a thickness of 8 nm, serving as a hole-blocking layer 350. Above the hole-blocking layer 350, ET-1 and Liq are deposited at a mass ratio of 1:1. The vacuum-deposited film of this material is 30 nm thick, forming an electron transport layer 360. On the electron transport layer 360, a 1 nm thick LiF layer is formed using a vacuum deposition apparatus, serving as an electron injection layer 370. On the electron injection layer 370, a 16 nm thick Mg:Ag electrode layer is formed using a vacuum deposition apparatus, with a Mg:Ag mass ratio of 1:9, serving as a second electrode (cathode) layer 400. On the cathode layer, a 15 nm thick compound 1 of the present invention is vacuum-deposited as a first capping layer; on the first capping layer, a 50 nm thick CP-H1 layer is vacuum-deposited as a second capping layer.

[0209] Blue light device examples 2-17

[0210] The device structure and fabrication method are similar to those of Device Example 1, except that the material types of the first and second cover layers are changed; the specific cover layers are described in Table 3 below.

[0211] Comparative Examples of Blue Light Devices 1-3, 8

[0212] The structures and fabrication methods of the blue light devices in Comparative Examples 1 to 3 and 8 are similar to those in Example 1, except that a single-layer cover layer is used instead of a double-layer cover layer. The specific cover layer materials and film thicknesses are described in Table 3 below.

[0213] Comparative Examples of Blue Light Devices 4-7

[0214] The devices in Comparative Examples 4 to 7 are similar in structure and fabrication method to those in Example 1, except that a comparative compound is used as the first capping layer material. The specific capping layer materials are described in Table 3 below.

[0215] The test data for the material of the capping layer in the OLED device, the current efficiency of the device, CIEy, and perceptible color difference are listed in Table 3.

[0216] Table 3

[0217]

[0218]

[0219] Note: Index = Current efficiency / CIEy, and is only applied to blue light devices. The efficiency of blue light devices is generally not determined by current efficiency, but by Index (industry standard); perceptible color difference, unit: JNCD; 1 JNCD = 0.004.

[0220] The data in Table 3 show that, compared with Comparative Example 1, a blue OLED device using the compound of the present invention as a dual-layer capping layer with a low-refractive-index first capping layer and a high-refractive-index second capping layer, the index of the blue OLED device is increased by 6.6% to 12.6%. Furthermore, the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even showing a reduction of 51.6% at 60° (device example 13). Therefore, the angle variation is smaller, and the color shift effect is significantly improved.

[0221] Compared to Comparative Example 2, a blue OLED device with only a low-refractive-index capping layer, the index of the blue OLED device using the compound of the present invention as a dual-layer capping layer with a low-refractive-index first capping layer and a high-refractive-index second capping layer is increased by 52.9% to 61.5%. Furthermore, the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even reduced by 36.8% at 60° (device example 13). Therefore, the angle variation is smaller, and the color shift effect is significantly improved.

[0222] Compared to Comparative Example 3, a blue OLED device with only a low-refractive-index capping layer of the comparative compound CP-R1, the index of the blue OLED device using the compound of the present invention as a low-refractive-index first capping layer and a high-refractive-index second capping layer is increased by 67.9% to 77.3%. Moreover, the color difference is significantly reduced at angles of 30°, 45°, and 60°, and in some cases even by 37.7% at 30° (device example 13). Therefore, the angle change is smaller and the color shift effect is significantly improved.

[0223] Compared with Comparative Example 4, which uses a double-layer capping layer with the compound CP-R1, the blue OLED device using the compound of the present invention as a double-layer capping layer with a low refractive index first capping layer and a high refractive index second capping layer has an index increase of 3.9% to 9.7%; and the color difference is significantly reduced at angles of 30°, 45° and 60°, some even by 31.5%@60° (device example 13), thus the angle change is smaller and the color shift effect is significantly improved.

[0224] Compared to Comparative Example 5, which uses a double-layer capping layer with the compound CP-R2, the blue OLED device using the compound of the present invention as a low-refractive-index first capping layer and a high-refractive-index second capping layer has an index increase of 5.5% to 11.4%. Furthermore, the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even showing a reduction of 38.7% at 60° (device example 13). As a result, the angle variation is smaller, and the color shift effect is significantly improved.

[0225] Compared to Comparative Example 6, which uses a double-layer capping layer with the compound CP-R3, the blue OLED device using the compound of the present invention as a low-refractive-index first capping layer and a high-refractive-index second capping layer has an index increase of 6.1% to 12.0%. Furthermore, the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even showing a reduction of 40.1% at 60° (device example 13). As a result, the angle variation is smaller, and the color shift effect is significantly improved.

[0226] Compared to Comparative Example 7, which uses a double-layer capping layer with the compound CP-R4, the blue OLED device using the compound of the present invention as a low-refractive-index first capping layer and a high-refractive-index second capping layer has an index increase of 6.4%-10.3%. Furthermore, the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even showing a reduction of 33.7% at 60° (device example 8, where the second capping layer is CP-H12). As a result, the angle variation is smaller, and the color shift effect is significantly improved.

[0227] Compared to Comparative Example 8, which only has a high-refractive-index capping layer, the blue OLED device using the compound of the present invention as a dual-layer capping layer with a low-refractive-index first capping layer and a high-refractive-index second capping layer has an index increase of 7.4%-113%; and the color difference is significantly reduced at angles of 30°, 45°, and 60°, with some even reduced by 55%@60° (device example 8, where the second capping layer is CP-H12). Therefore, the angle change is smaller, and the color shift effect is significantly improved.

[0228] It should be understood that the smaller the perceptible color difference and the smaller the amount of color change, the better the angle dependence of the emitted light wavelength of the organic electroluminescent device is suppressed.

[0229] In summary, the compound of the present invention, used as the first capping layer material in combination with a high refractive index second capping layer, forms a double capping layer that, when applied to OLED devices, significantly improves light extraction efficiency, current efficiency, and angle dependence, while maintaining excellent device light extraction efficiency and apparent polarization performance at high temperatures.

[0230] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An organic compound based on a borazine core, characterized by, The organic compound has a structure as shown in general formula (1): In general formula (1), L1, L2, L3, L4, L5, L6 each independently represents substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted biphenylene; L1, L2, L3, L4, L5, L6 can be the same or different; Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 each independently represents a structure as shown in general formula (2), general formula (3), general formula (4); Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 are the same or different; In General Formula (2), General Formula (3), Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z 10 Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y 10 each independently represents C-H, C-R or N; R each occurrence independently represents a fluorine atom, a cyano group, a substituted or unsubstituted C1-C20 branched or straight chain alkyl group, a substituted or unsubstituted C1-C20 cycloalkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group; The C1-C20 branched or straight chain alkyl group is methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, sec-butyl, neopentyl, n-pentyl, iso-pentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl or 1-butylpentyl; The C1-C20 cycloalkyl group is cyclohexane, adamantane, cyclopentane, phenyl, naphthyl, biphenyl; In general formula (2), general formula (3), R1, R2, R3, R4, R5, R6, R7, R8, R9 each independently represents a hydrogen atom, a fluorine atom, -CF3, -CF2CF3; at least one of R1, R2, R3 does not represent a hydrogen atom; at least one of R4 to R9 exists and does not represent a hydrogen atom; R1, R2, R3, R4, R5, R6, R7, R8, R9 are the same or different; In general formula (2), m = 1, 2, 3, 4 or 5; In general formula (3), a, b each independently represents 0, 1, 2, 3; a+b≥1; e, d each independently represents 0, 1, 2, 3, 4, 5, e+d≥1; In general formula (4), Ar7, Ar8 each independently represents general formula (2), general formula (3), a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group; at least one of Ar7, Ar8 represents general formula (2) or general formula (3); The substituent of the "substituted or unsubstituted" group is optionally selected from one or more of a deuterium atom, a halogen atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a perfluoroethyl group, a perfluoroisopropyl group, a perfluoro-t-butyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a t-butoxy group, a cyclohexane, an adamantane, a cyclopentane, a phenyl group, a naphthyl group, a biphenyl group.

2. The organic compound according to claim 1, characterized by The structure of the organic compound is shown in general formula (5); Wherein, Ar1, Ar2, L1, L2 are as defined in claim 1.

3. The organic compound according to claim 1, characterized by R1, R2, R3, R4, R5, R6, R7, R8, R9 all represent a fluorine atom.

4. The organic compound according to claim 1, wherein The structure of general formula (2) is: Any one of them; The structure of general formula (3) is: any of the foregoing; The structure of the general formula (4) is: any of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14 a, b each independently represents 0, 1, 2 or 3; e, d each independently represents 0, 1, 2, 3, 4 or 5.

5. The organic compound according to claim 1, wherein The structure of the general formula (2) is: Any of the following: 2,4-dichlorophenoxyacetic acid; 2,4-dichlorophenoxypropionic acid; 2,4 any of the foregoing; The structure of the general formula (4) is: any of the foregoing.

6. An organic compound based on a borazine core, characterized in that The organic compound has a structure as shown in general formula (1): In general formula (1), L1, L2, L3, L4, L5, L6 each independently represents a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted biphenylene group; L1, L2, L3, L4, L5, L6 can be the same or different; Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 each independently represents a structure as shown in general formula (2), general formula (3), general formula (4); Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 are the same or different; In General Formula (2), General Formula (3), Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z 10 Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y 10 each occurrence, the same or different, independently represents C-H, C-R, or N; The R represents one of a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group; In general formula (2), general formula (3), R1, R2, R3, R4, R5, R6, R7, R8, R9 each independently represents a hydrogen atom, a fluorine atom, -CF3, -CF2CF3; at least one of R1, R2, R3 does not represent a hydrogen atom; at least one of R4 to R9 exists and does not represent a hydrogen atom; R1, R2, R3, R4, R5, R6, R7, R8, R9 are the same or different; In general formula (2), m = 1, 2, 3, 4 or 5; In general formula (3), a, b each independently represents 0, 1, 2, 3; a+b≥1; e, d each independently represents 0, 1, 2, 3, 4, 5, e+d≥1; In general formula (4), Ar7, Ar8 each independently represents general formula (2), general formula (3), a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group; at least one of Ar7, Ar8 represents general formula (2) or general formula (3); The "substituted or unsubstituted" substituent is optionally selected from one or more of a protium atom, a deuterium atom, a fluorine atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a phenyl group, a naphthyl group, a biphenyl group.

7. An organic compound based on a borazine core, characterized in that, The organic compound has a structure as shown in general formula (1): In general formula (1), L1, L2, L3, L4, L5, L6 each independently represents a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted biphenylene group; L1, L2, L3, L4, L5, L6 can be the same or different; Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 each independently represents a structure shown in general formula (2), general formula (3); Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 are the same or different; In General Formula (2), General Formula (3), Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z 10 Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y 10 each independently represents C-H, C-R or N; R each occurrence, the same or different, each independently represents a fluorine atom, a cyano group, a substituted or unsubstituted C1-C20 branched or straight chain alkyl group, a substituted or unsubstituted C1-C20 cycloalkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group; the C1-C20 branched or straight chain alkyl group is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a sec-butyl group, a neopentyl group, a n-pentyl group, an iso-pentyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, or a 1-butylpentyl group; the C1-C20 cycloalkyl group is a cyclohexane group, an adamantane group; in general formula (2), general formula (3), R1, R2, R3, R4, R5, R6, R7, R8, R9 each independently represents a hydrogen atom, a fluorine atom, -CF3, -CF2CF3; at least one of R1, R2, R3 does not represent a hydrogen atom; at least one of R4 to R9 exists and does not represent a hydrogen atom; R1, R2, R3, R4, R5, R6, R7, R8, R9 are the same or different; in general formula (2), m = 1, 2, 3, 4, or 5; in general formula (3), a, b each independently represents 0, 1, 2, 3; a + b ≥ 1; e, d each independently represents 0, 1, 2, 3, 4, 5, e + d ≥ 1; the substituent of the "substituted or unsubstituted" group is optionally selected from one or more of a deuterium atom, a halogen atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a perfluoroethyl group, a perfluoroisopropyl group, a perfluoro-tert-butyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a cyclohexane group, an adamantane group, a cyclopentane group, a phenyl group, a naphthyl group, a biphenyl group.

8. The organic compound according to claim 7, characterized by the structure of general formula (2) is: Any one of them; the structure of general formula (3) is: any of the foregoing. 9.The organic compound according to claim 7, characterized by the structure of general formula (2) is: Any of the following: 2,4-dichlorophenoxyacetic acid; 2,4-dichlorophenoxypropionic acid; 2,4 any of the foregoing.

10. An organic compound based on a borazine core, characterized in that, the organic compound has a structure shown in general formula (1): in general formula (1), L1, L2, L3, L4, L5, L6 each independently represents a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted biphenylene group; L1, L2, L3, L4, L5, L6 can be the same or different; Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 each independently represents a structure shown in general formula (2), general formula (3); Ar1, Ar2, Ar3, Ar4, Ar5, Ar6 are the same or different; In General Formula (2), General Formula (3), Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z 10 Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y 10 each independently represents C-H, C-R or N; R represents one of a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted terphenyl group; In general formula (2) and general formula (3), R1, R2, R3, R4, R5, R6, R7, R8, and R9 each independently represent a hydrogen atom, a fluorine atom, -CF3, or -CF2CF3; at least one of R1, R2, and R3 does not represent a hydrogen atom; at least one of R4 to R9 exists and does not represent a hydrogen atom; R1, R2, R3, R4, R5, R6, R7, R8, and R9 are the same or different; In general formula (2), m = 1, 2, 3, 4, or 5; In general formula (3), a and b each independently represent 0, 1, 2, or 3; a + b ≥ 1; e and d each independently represent 0, 1, 2, 3, 4, or 5; and e + d ≥ 1. The "substituted or unsubstituted" substituent is optionally one or more of a protium atom, a deuterium atom, a fluorine atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethyl group, a difluoromethoxy group, a fluoromethyl group, a fluoromethoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a phenyl group, a naphthyl group, or a biphenyl group.

11. An organic compound based on a borazine core, characterized in that, The specific structural formula of the organic compound is any one of the following structures:

12. The organic compound based on a borazine core according to any one of claims 1 to 11, characterized in that The refractive index of the organic compound under blue light with a wavelength of 460 nm ranges from 1.4 to 1.

7.

13. The organic compound based on a borazine core according to any one of claims 1 to 11, wherein The refractive index of the organic compound under blue light with a wavelength of 460 nm ranges from 1.4 to 1.

6.

14. An organic electroluminescent device, comprising: a substrate layer; a first electrode over the substrate; an organic light-emitting functional layer over the first electrode; a second electrode over the organic light-emitting functional layer; and a cover layer over the second electrode; characterized in that the cover layer comprises one or more of the organic compounds based on borazine as claimed in any one of claims 1 to 11.

15. The organic electroluminescent device according to claim 14, wherein the cover layer comprises a first cover layer and a second cover layer, the first cover layer being over the second electrode; the second cover layer being over the first cover layer; the first cover layer comprising one or more of the organic compounds based on borazine as the core as claimed in any one of claims 1 to 11. characterized in that The refractive index of the first cover layer material is less than that of the second cover layer material.

16. The organic electroluminescent device according to claim 14, wherein The refractive index of the first cover layer material at a wavelength of 460 nm is less than or equal to 1.

65.

17. The organic electroluminescent device according to claim 15, wherein The refractive index of the second cover layer material at a wavelength of 460 nm is greater than or equal to 1.

85.

18. The organic electroluminescent device according to claim 15, wherein The difference between the refractive indices of the second cover layer material and the first cover layer material at a wavelength of 460 nm is greater than or equal to 0.

3.

19. The organic electroluminescent device according to claim 15, wherein ​ 20. The organic electroluminescent device according to claim 15, wherein The first cladding layer material has a bandgap Eg greater than 3.0 eV.

21. The organic electroluminescent device according to claim 15, wherein The first cladding layer material has a bandgap Eg greater than 3.5 eV.

22. The organic electroluminescent device according to claim 15, wherein The first cladding layer material has a refractive index difference between 460 nm and 620 nm wavelengths of < 0.3.

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