Carbazole compound and organic electroluminescent element

Abstract

The purpose of the present invention is to provide a compound having a high refractive index of 450-750 nm in a capping layer and a low extinction coefficient in order to improve the light extraction efficiency of an organic EL element. The present invention relates to a compound in which a molecule has been designed by substituting a quinoxalinyl group or a quinazolinyl group into a carbazole skeleton in view of excellent stability and durability of a thin film of a specific carbazole compound and in which the refractive index can be further increased by adjusting the molecular structure. An organic EL element having excellent luminous efficiency is obtained by using the compound according to the present invention as a material constituting a capping layer.

Description

Technical Field

[0001] This invention relates to compounds suitable for self-emissive electronic components for various display devices, particularly carbazole compounds suitable for organic electroluminescent elements (hereinafter referred to as organic EL elements), and organic EL elements, electronic components, and electronic devices using such compounds. Background Technology

[0002] Organic EL elements are self-emissive, and therefore have superior brightness and visibility compared to liquid crystal elements, enabling vivid displays. As a result, they have been actively researched.

[0003] In 1987, CWTang et al. of Eastman Kodak developed a layered structure element that distributed various functions among different materials, making organic EL elements using organic materials practical devices. They layered electron-transferring phosphors and hole-transferring organic materials, injecting the charges of both into the phosphor layer to induce luminescence, thereby achieving 1000 cd / m² at voltages below 10V. 2 The above high brightness (for example, see Patent Document 1 and Patent Document 2).

[0004] To date, numerous improvements have been made to make organic EL devices practical. By further subdividing the functions of each layer of the stacked structure and sequentially setting an anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode on a substrate, a bottom-emitting structure light-emitting device that emits light from the bottom has been made, thereby gradually achieving high efficiency and durability (for example, see Non-Patent Literature 1).

[0005] In recent years, top-emitting light-emitting elements, which use a metal with a high work function as the anode and emit light from the top, have become increasingly common. In bottom-emitting structures, where light is extracted from the bottom where pixel circuitry is located, the area of ​​the light-emitting portion is limited. In contrast, in top-emitting light-emitting elements, the pixel circuitry is not obstructed by the light extraction from the top, thus providing the advantage of expanding the light-emitting portion. In top-emitting light-emitting elements, semi-transparent electrodes such as LiF / Al / Ag (e.g., see Non-Patent Document 2), Ca / Mg (e.g., see Non-Patent Document 3), and LiF / MgAg are used as the cathode.

[0006] In such light-emitting elements, when light emitted from the light-emitting layer is incident on other films, total internal reflection occurs at the interface between the light-emitting layer and other films if the light is incident at an angle greater than a certain angle. Therefore, only a portion of the emitted light can be utilized. In recent years, in order to improve the light extraction efficiency, light-emitting elements with a high-refractive-index "capping layer" disposed on the outside of a semi-transparent electrode with a low refractive index have been proposed (for example, see Non-Patent Documents 2 and 3).

[0007] As an effect of the capping layer in a top-emitting light-emitting element, in a light-emitting element using Ir(ppy)3 as the luminescent material, the current efficiency without the capping layer is 38 cd / A, compared to 64 cd / A in a light-emitting element using ZnSe with a film thickness of 60 nm as the capping layer, confirming an efficiency improvement of approximately 1.7 times. Furthermore, it is shown that the maximum transmittance of the semi-transparent electrode and the capping layer does not necessarily coincide with the maximum efficiency, indicating that the maximum light extraction efficiency is determined by interference effects (for example, see Non-Patent Document 3).

[0008] Previously, high-precision metal masks were used for the formation of capping layers. However, under high-temperature conditions, the metal mask deforms due to heat, resulting in reduced alignment accuracy. Therefore, for ZnSe with a melting point as high as 1100°C or higher, it is impossible to deposit it in the correct position using a high-precision metal mask, which may adversely affect the light-emitting element (see, for example, Non-Patent Document 3). Furthermore, even film formation using sputtering methods can adversely affect the light-emitting element, making capping layers with inorganic materials unsuitable.

[0009] Furthermore, tris(8-hydroxyquinoline)aluminum (hereinafter abbreviated as Alq3) has been proposed as a capping layer to adjust the refractive index (see, for example, Non-Patent Literature 2). However, Alq3 is known to be an organic EL material commonly used as a green light-emitting material or an electron transport material, and it has weak absorption around 450 nm, which is close to the emission wavelength of cyan light-emitting materials. Therefore, in the case of cyan light-emitting elements, there are also problems of reduced color purity and reduced light extraction efficiency.

[0010] In order to improve the device characteristics of organic EL devices and to significantly improve the light extraction efficiency, materials with high refractive index, low extinction coefficient, and excellent film stability and durability are sought as the capping layer.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: US Patent No. 5,792,557

[0014] Patent Document 2: US Patent No. 5639914

[0015] Patent Document 3: International Publication No. 2014 / 009310

[0016] Patent Document 4: Korean Patent Registration No. 10-2164767

[0017] Patent Document 5: International Publication No. 2023 / 048118

[0018] Non-patent literature

[0019] Non-patent literature 1: Proceedings of the 9th Workshop of the Chinese Society of Applied Physics, 2001, pp. 55-61

[0020] Non-patent literature 2: Appl. Phys. Lett., (USA), 2001, Vol. 78, pp. 544-546.

[0021] Non-patent literature 3: Appl. Phys. Lett., (USA), 2003, Vol. 82, pp. 466-468.

[0022] Non-patent literature 4: Tetrahedron (Netherlands), 2002, Vol. 58, 9633-9695

[0023] Non-patent literature 5: Appl. Phys. Lett., (USA), 2011, Vol. 98, p. 083302 Summary of the Invention

[0024] The object of this invention is to provide a compound with a high refractive index and a low extinction coefficient in the wavelength range of 450 nm to 750 nm, suitable as a capping layer material for organic EL elements. Furthermore, it aims to provide an organic EL element in which the light extraction efficiency is improved by using the aforementioned compound.

[0025] The physical properties of compounds suitable for capping layers of organic EL elements include (1) high refractive index; (2) low extinction coefficient; (3) vapor deposition capability; (4) stable thin film state; and (5) high glass transition temperature. Furthermore, the physical properties of the organic EL element to be provided in this invention include (1) high light extraction efficiency; (2) no reduction in color purity; (3) no time-varying light transmission; and (4) long lifespan.

[0026] Therefore, in order to achieve the above-mentioned objectives, the inventors focused on the excellent stability and durability of carbazole compound films and developed a material with high refractive index and low extinction coefficient in the wavelength range of 450 nm to 750 nm by optimizing the molecular design. Furthermore, organic EL devices using this compound were fabricated, and the characteristics of the devices were thoroughly evaluated. As a result, the previous problems were solved, and thus the present invention was completed.

[0027] That is, the present invention provides the following carbazole compound represented by the following general formula (I) and the organic EL element using the same.

[0028] 1) Carbazole compounds represented by the following general formula (I),

[0029] [Chemistry 1]

[0030]

[0031] In the formula, A, B, and C each independently represent a substituted or unsubstituted monovalent aryl group, or a substituted or unsubstituted monovalent heteroaryl group.

[0032] However, C is not benzoxazolyl, and at least two of A, B, and C represent substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinoxalinyl groups.

[0033] L1 to L3 each independently represent a single bond, an unsubstituted divalent aryl group, or an unsubstituted divalent heteroaryl group.

[0034] 2) The carbazole compound according to 1) is represented by the following general formula (II),

[0035] [Chemistry 2]

[0036]

[0037] In the formula, A, B, C and L1 to L3 are as defined in the general formula (I) above.

[0038] 3) The carbazole compound according to 2), wherein L1 to L3 in the above general formula (II) are each independently a single bond, an unsubstituted phenylene group, an unsubstituted pyridylene group, or an unsubstituted naphthylene group.

[0039] 4) The carbazole compound according to 3), wherein A and B, or A and C, in the above general formula (II) are each independently substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinoxalinyl.

[0040] 5) The carbazole compound according to 4), wherein L1 and L2 in the above general formula (II) are single bonds.

[0041] A and B are each independently substituted quinoxalinyl or substituted quinazolinyl.

[0042] 6) The carbazole compound according to 5), wherein A and B in the above general formula (II) are each independently substituted 6-quinoxalinyl or substituted 6-quinoxalinyl.

[0043] 7) The carbazole compound according to 4), wherein L1 and L2 in the above general formula (II) are single bonds, and A and B are each independently an unsubstituted quinoxalinyl group or an unsubstituted quinoxalinyl group; or

[0044] In the above general formula (II), L1 and L3 are single bonds.

[0045] A and C are each independently an unsubstituted quinoxalinyl group or an unsubstituted quinazolinyl group.

[0046] 8) The carbazole compound according to 7), wherein A and B in the above general formula (II) are each independently unsubstituted 2-quinoxalinyl or unsubstituted 2-quinoxalinyl.

[0047] 9) The carbazole compound according to 4), wherein L1 and L2 in the above general formula (II) are each independently unsubstituted phenylene, unsubstituted pyridylene, or unsubstituted naphthylene.

[0048] A and B are each independently an unsubstituted quinoxalinyl group or an unsubstituted quinazolinyl group.

[0049] 10) The carbazole compound according to 7), wherein A and B in the above general formula (II) are each independently unsubstituted 2-quinoxalinyl or unsubstituted 2-quinoxalinyl.

[0050] 11) The carbazole compound according to 2), wherein C in the above general formula (II) is naphthyl, cyanophenyl, pyridinyl, quinolinyl, quinoxalinyl, quinazolinyl, benzothiazolyl, or oxazolopyridinyl.

[0051] 12) The carbazole compound according to 11), wherein C in the above general formula (II) is 2-naphthyl, 4-cyanophenyl, 3-pyridyl, 4-pyridyl, 2-quinolinyl, 3-quinolinyl, 6-quinolinyl, 7-quinolinyl, 2-quinoxalinyl, 6-quinoxalinyl, 2-quinazolinyl, 6-quinazolinyl, 7-quinazolinyl, 2-benzothiazolyl, or 2-oxazolopyridyl.

[0052] 13) An organic EL element having at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a capping layer in sequence, wherein the capping layer contains any one of the carbazole compounds in 1) to 12).

[0053] 14) The organic EL element according to 13), wherein the refractive index of the vapor-deposited film of the carbazole compound of any one of 1) to 12) on a silicon substrate with a vacuum evaporation thickness of 80 nm, measured at room temperature (25±2℃), is 1.70 or higher, with a wavelength of 450 nm or more and 750 nm or less.

[0054] 15) The organic EL element according to 13), wherein the capping layer is a stacked or mixed layer containing two or more compounds, and at least one of the compounds is a carbazole compound as described in any one of 1) to 12).

[0055] 16) An electronic device or electronic component having a pair of electrodes and at least one organic layer sandwiched therebetween, containing any one of the carbazole compounds in 1) to 12).

[0056] The effects of the invention

[0057] Regarding the carbazole compound represented by general formula (I) of the present invention, since (1) it has a high refractive index in the range of wavelengths above 450 nm and below 750 nm, (2) it has a low extinction coefficient, (3) it can be vapor-deposited, (4) it has a stable thin film state, and (5) it has high heat resistance, it can significantly improve the light extraction efficiency by being provided as a capping layer on the outside of the transparent or semi-transparent electrode of the organic EL element. Attached Figure Description

[0058] Figure 1 The diagram shows the structure of compounds 1 to 15 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0059] Figure 2 The diagram shows the structure of compounds 15 to 27 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0060] Figure 3 The diagram shows the structure of compounds 28 to 39 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0061] Figure 4 The diagram shows the structure of compounds 40 to 48 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0062] Figure 5 The diagrams show the structures of compounds 49 to 60, which are examples of carbazole compounds represented by general formula (I) of the present invention.

[0063] Figure 6 The diagram shows the structure of compounds 61 to 75 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0064] Figure 7 The diagram shows the structure of compounds 76 to 87 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0065] Figure 8 The diagram shows the structure of compounds 88 to 97, which are examples of carbazole compounds represented by general formula (I) of the present invention.

[0066] Figure 9 The diagram shows the structure of compounds 98 to 112 as examples of carbazole compounds represented by general formula (I) of the present invention.

[0067] Figure 10 A diagram illustrating an example of the structure of the organic EL element of the present invention. Detailed Implementation

[0068] The compounds of the present invention are those represented by the above general formula (I).

[0069] The aromatic ring of the "monovalent aryl group" representing "substituted or unsubstituted monovalent aryl group" in general formula (I) can be a monocyclic ring, a fused ring of two or more rings, a linking ring of two or more rings connected by a single bond, or a spirocyclic ring of two or more rings connected by a helical bond. In the case of a fused ring, the number of fused rings is preferably 2 to 6, for example, 2 to 4. In the case of a linking ring, the number of linked rings is preferably 2 to 6, for example, 2 to 4. The number of carbon atoms in the aromatic ring is, for example, 6 to 30, 6 to 22, 6 to 18, 6 to 14, or 6 to 10. Specific examples of "monovalent aromatic hydrocarbon groups" in A, B, and C include phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, indole, pyrene, peryl, fluoranyl, benzo[9,10]phenanthryl, fluorenyl, spirobisfluorenyl, and other aryl groups with 6 to 30 carbon atoms.

[0070] The aromatic heterocycle constituting the "monovalent heteroaryl" in "substituted or unsubstituted monovalent heteroaryl" represented by A, B, and C in general formula (I) can be a monocyclic ring or a fused ring of two or more rings. In the case of a fused ring, the number of fused rings is preferably 2 to 6, for example, 2 to 4. Examples of heteroatoms constituting the aromatic heterocycle include nitrogen, oxygen, and sulfur atoms. The number of carbon atoms in the aromatic heterocycle is, for example, 2 to 40, for example, 2 to 30, for example, 2 to 18. Specific examples of "monovalent heteroaryl" in A, B, and C include pyridyl, pyrimidinyl, triazinyl, furanyl, pyrrolithyl, thiopheneyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiopheneyl, indolyl, carbazolyl, benzooxazolyl, benzothiazolyl, indolopyridyl, oxazolopyridyl, oxazolopyrazinyl, quinoxolinyl, quinazololyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiopheneyl, naphridyl, phenanthrololinyl, acridineyl, and carbazolyl, which have 2 to 20 carbon atoms.

[0071] For “substituted or unsubstituted monovalent fused polycyclic aromatic groups”, please refer to the description and specific examples of fused rings consisting of two or more rings in the above description of “substituted or unsubstituted monovalent aryl groups” and “substituted or unsubstituted monovalent heteroaryl groups”.

[0072] As L1 to L3 in general formula (I) represent "substituted or unsubstituted divalent aryl" or "substituted or unsubstituted divalent heteroaryl", divalent groups that remove one hydrogen atom from "monovalent aryl" or "monovalent heteroaryl" represented by A, B and C in general formula (I) can be listed, for example, divalent groups that remove one hydrogen atom from the specific groups listed above.

[0073] As the "substituent" in "substituted monovalent aryl" or "substituted monovalent heteroaryl" represented by A, B, and C in general formula (I), specifically, examples can be listed.

[0074] Deuterium atom, cyano group, nitro group;

[0075] Halogen atoms such as fluorine, chlorine, bromine, and iodine;

[0076] Trimethylsilyl, triphenylsilyl, and other silyl groups;

[0077] Alkyl groups such as methyl, ethyl, and propyl, which are straight-chain or branched with 1 to 6 carbon atoms;

[0078] Alkoxy groups, such as methoxy, ethoxy, and propoxy, which are straight-chain or branched alkoxy groups with 1 to 6 carbon atoms;

[0079] vinyl, allyl, and other alkenyl groups;

[0080] Aryl groups with 6 to 30 carbon atoms, including phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthrene, fluorenyl, spirobisfluorenyl, indyl, pyrene, perylene, fluoranyl, benzo[9,10]phenanthrene, etc.

[0081] Pyridyl, pyrimidinyl, triazinyl, thiopheneyl, furanyl, pyrroloyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiopheneyl, indolyl, carbazoyl, benzooxazolyl, benzothiazoyl, imidazopyridyl, oxazolyl, oxazolylpyrazinyl, quinoxolinyl, quinazolyl, benzoimidazoyl, pyrazolyl, dibenzofuranyl, dibenzothiopheneyl, naphridyl, acridineyl, carbazoyl, phenanthroline, and other heteroaryl groups with 2 to 20 carbon atoms;

[0082] aryl groups such as phenoxy and toluoxy;

[0083] Benzyloxy, phenylethoxy, and other arylalkoxy groups, etc.

[0084] The hydrogen atoms of these substituents can be further replaced by substituents exemplified herein. Among preferred substituents, those comprising deuterium atoms, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 atoms forming a cyclic skeleton are used. It should be noted that for substituents that replace the parent skeleton (aromatic hydrocarbon group, aromatic heterocyclic group), the substituent that replaces the first substituent is sometimes called a "first substituent," and the substituent that replaces the first substituent is called a "second substituent." Wherein, if the first substituent contains a benzene ring, the benzene ring can bond with the parent skeleton to form a cyclic structure. Furthermore, where two or more substituents replace the benzene ring of the first substituent, adjacent substituents can bond with each other to form a cyclic structure. The bonding between the benzene ring in the first substituent and the parent skeleton, and the bonding between the second substituents, can be a single bond or a bond formed by a linking group. Examples of linking groups include substituted or unsubstituted methylene groups, oxygen atoms, or sulfur atoms.

[0085] The "substituents" in "substituted divalent aryl" or "substituted divalent heteroaryl" represented by L1 to L3 in general formula (I) can be listed as the same groups as the groups exemplified as "substituted aryl" or "substituted heteroaryl" represented by A, B, and C in general formula (I), and the forms they can take can be listed as the same forms.

[0086] In the general formula (I) of the compounds of the present invention, at least two of A, B, and C represent substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinazolinyl groups, preferably at least two of A, B, and C are substituted or unsubstituted 2-quinoxalinyl, substituted or unsubstituted 6-quinoxalinyl, substituted or unsubstituted 2-quinazolinyl, or substituted or unsubstituted 6-quinazolinyl, particularly preferably at least two of A, B, and C are unsubstituted 2-quinoxalinyl, substituted 6-quinoxalinyl, unsubstituted 2-quinazolinyl, or substituted 6-quinazolinyl.

[0087] The compounds of the present invention preferably have a group in formula (I) where A, B, and C are either unsubstituted or unsubstituted quinoxalinyl groups, or substituted or unsubstituted quinazolinyl groups are naphthyl, cyanophenyl, pyridinyl, quinolinyl, benzothiazolyl, or oxazolopyridinyl, particularly preferably 2-naphthyl, 4-cyanophenyl, 3-pyridinyl, 4-pyridinyl, 4-pyridinyl, 2-quinolinyl, 3-quinolinyl, 6-quinolinyl, 7-quinolinyl, 2-quinoxalinyl, 6-quinoxalinyl, 2-quinazolinyl, 6-quinoxalinyl, 2-quinazolinyl, 6-quinazolinyl, 7-quinazolinyl, 2-benzothiazolyl, or 2-oxazolopyridinyl.

[0088] In general formula (I), A, B, and C can be any combination selected from the above-mentioned groups. Preferably, A and B are substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinazolinyl, and C is a group other than these. Alternatively, A and C are substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinazolinyl, and B is a group other than these.

[0089] In general formula (I), L1 to L3 are preferably single bonds, unsubstituted phenylene, unsubstituted pyridylene, or unsubstituted naphthylene, more preferably single bonds or unsubstituted phenylene. L1 to L3 may be the same as each other or different.

[0090] In organic EL devices, the thickness of the capping layer is preferably in the range of 30 nm to 120 nm, and particularly preferably in the range of 40 nm to 80 nm.

[0091] The carbazole compound represented by the above general formula (I) is a novel compound. For example, it can be synthesized by a coupling reaction using a known palladium catalyst or the like (see, for example, Non-Patent Literature 4).

[0092] Specific examples of preferred compounds among the carbazole compounds represented by the above general formula (I) are shown in Figures 1 to 8 However, it is not limited to these compounds.

[0093] There are no particular limitations on the purification of carbazole compounds represented by the above general formula (I). Well-known methods for the purification of organic compounds, such as purification by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., recrystallization purification using solvents, crystallization purification, and sublimation purification, can be used. The identification of the compound can be performed by NMR analysis.

[0094] For the physical properties of the carbazole compound represented by the above general formula (I), it is preferable to measure the melting point, glass transition temperature (Tg), refractive index, and extinction coefficient. The melting point serves as an indicator of vapor deposition performance, the glass transition temperature (Tg) serves as an indicator of the stability of the thin film state, and the refractive index and extinction coefficient serve as indicators related to the improvement of light extraction efficiency.

[0095] Melting point and glass transition temperature (Tg) can be determined using powder and a high-sensitivity differential scanning calorimeter (BLUC). Measured using DSC3100SA (manufactured by Estec).

[0096] The refractive index and extinction coefficient can be measured by fabricating an 80 nm thin film on a silicon substrate using a spectrophotometer (F10-RT-UV manufactured by Philmetry).

[0097] As for the structure of organic EL devices, for example, in the case of a top-emitting light-emitting device, a structure can be listed where an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer are sequentially arranged on a glass substrate. Other examples include structures with a hole injection layer between the anode and the hole transport layer, structures with an electron blocking layer between the hole transport layer and the light-emitting layer, structures with a hole blocking layer between the light-emitting layer and the electron transport layer, and structures with an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, a single organic layer can perform multiple functions; for example, it can be configured to function as both a hole injection layer and a hole transport layer, both a hole transport layer and an electron blocking layer, both a hole blocking layer and an electron transport layer, and both an electron transport layer and an electron injection layer. Furthermore, it is also possible to fabricate a structure by stacking two or more organic layers with the same function, such as a structure by stacking two hole transport layers, two light-emitting layers, two electron transport layers, or two capping layers.

[0098] The total thickness of all layers in the organic EL element is preferably 200 nm to 750 nm, more preferably 350 nm to 600 nm. Furthermore, the thickness of the capping layer is preferably 30 nm to 120 nm, more preferably 40 nm to 80 nm. In this case, good light extraction efficiency is obtained. It should be noted that the thickness of the capping layer can be appropriately changed depending on the type of light-emitting material used in the light-emitting element, the thickness of the organic EL element other than the capping layer, etc.

[0099] As the anode of organic EL elements, electrode materials with high work functions, such as indium tin oxide (ITO) and gold, are used.

[0100] Materials used as hole injection layers in organic EL elements can be arylamine compounds with a structure in which three or more triphenylamine structures are linked by single bonds or divalent groups without heteroatoms. Examples include starburst-type triphenylamine derivatives, various triphenylamine tetramers, porphyrin compounds represented by copper phthalocyanine, acceptor heterocyclic compounds such as hexacyanoazabenzo[9,10]phenanthrene, and coating-type polymers. These can be used individually as films, as monolayers mixed with other materials, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers. These materials can be used to form thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0101] Materials used as hole transport layers in organic EL elements include benzidine derivatives such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (hereinafter referred to as TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine, and N,N,N',N'-tetra(biphenyl)benzidine, as well as 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane. Particularly preferred are arylamine compounds having a structure in which two triphenylamine structures are linked by single bonds or divalent groups without heteroatoms, such as N,N,N',N'-tetra(biphenyl)benzidine. Furthermore, arylamine compounds having a structure in which three or more triphenylamine structures are linked by single bonds or divalent groups without heteroatoms, such as various triphenylamine trimers and tetramers, are preferred. These materials can be used individually as films, as monolayers mixed with other materials, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers. Furthermore, coating-type polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) can be used as hole injection / transport layers. These materials can be used to form thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0102] In addition, as materials for the hole injection layer and the hole transport layer, products that are further P-doped with dopants such as tri(bromophenyl)amine antimony hexachloride and axial alkene derivatives (for example, see Patent Document 3) that are commonly used in this layer, and polymeric compounds such as TPD that have a structure of benzidine derivatives in part of their structure can be used.

[0103] Furthermore, electron blocking layers can also be stacked in organic EL devices. Materials used for electron blocking layers include carbazole derivatives such as 4,4',4''-tris(N-carbazole-9-yl)triphenylamine (hereinafter referred to as TCTA), 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene, 1,3-bis(carbazole-9-yl)benzene (hereinafter referred to as mCP), and 2,2-bis(4-carbazole-9-ylphenyl)adamantane, as well as compounds with triphenylsilyl and triarylamine structures, represented by 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene, which possess electron blocking properties. These can be used individually as films, as monolayers mixed with other materials, or as stacked structures between individually formed layers, between mixed layers, or between individually formed layers and mixed layers. These materials can be used to form thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0104] Materials used for the light-emitting layer of organic EL elements include metal complexes of quinoline phenol derivatives such as Alq3, various metal complexes, anthracene derivatives, bis(styrene)benzene derivatives, pyrene derivatives, oxazole derivatives, and poly(p-phenylene)ethylene derivatives. Alternatively, the light-emitting layer can be constructed using a host material and a dopant material. Anthracene derivatives are preferred as the host material. In addition to the aforementioned light-emitting materials, heterocyclic compounds with a partial structure having an indole ring as a fused ring, heterocyclic compounds with a partial structure having a carbazole ring as a fused ring, carbazole derivatives, thiazole derivatives, benzimidazole derivatives, and polydialkylfluorene derivatives can also be used. As dopant materials, quinacridones, coumarins, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, and aminostyrene derivatives can be used; green light-emitting materials are particularly preferred. These can be used individually as films, or as single layers mixed with other materials to form films, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers.

[0105] Alternatively, phosphorescent materials can also be used as luminescent materials. Phosphorescent materials composed of metal complexes such as iridium and platinum can be used. For example, green phosphorescent materials such as Ir(ppy)3, cyan phosphorescent materials such as Firpic and Fir6, and red phosphorescent materials such as Btp2Ir(acac) can be used, with green phosphorescent materials being particularly preferred. As the host material, carbazole derivatives such as 4,4'-bis(N-carbazolyl)biphenyl, TCTA, and mCP can be used as the host material for hole injection and transport, while p-bis(triphenylsilyl)benzene and 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) can be used as the host material for electron transport.

[0106] Regarding the doping of phosphorescent luminescent materials into the host material, in order to avoid concentration extinction, it is preferable to do so by co-evaporation in the range of 1 to 30% by weight relative to the overall luminescent layer.

[0107] Alternatively, materials with delayed fluorescence, such as PIC-TRZ, CC2TA, PXZ-TRZ, and 4CzIPN CDCB derivatives, can also be used as luminescent materials (see, for example, Non-Patent Document 5). These materials can be thin-film formed using known methods such as vapor deposition, spin coating, and inkjet printing.

[0108] Alternatively, hole-blocking layers can be stacked in organic EL devices. Materials used for hole-blocking layers include phenanthrene derivatives such as copper hydroxide, metal complexes of quinolinephenol derivatives such as bis(2-methyl-8-hydroxyquinoline)-4-phenylphenol aluminum(III) (hereinafter referred to as BAlq), various rare earth complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, benzo[a]azole derivatives, and other compounds with hole-blocking properties. These materials can be used as electron transport layer materials. They can be formed individually, as monolayers mixed with other materials, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers. These materials can be used to form thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0109] As electron transport layers for organic electroluminescent (EL) devices, metal complexes of quinoline phenol derivatives such as Alq3 and BAlq, various metal complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, pyridine derivatives, benzimidazole derivatives, benzoxazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridoindole derivatives, phenanthroline derivatives, and thiophene derivatives can be used. These can be used individually as films, as monolayers mixed with other materials, or as laminates between individually formed layers, between mixed layers, or between individually formed layers and mixed layers. These materials can be used to form thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0110] As the electron injection layer of an organic EL element, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal complexes of quinoline phenol derivatives such as lithium quinoline phenol, metal oxides such as aluminum oxide, and metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr) and cesium (Cs) can be used. In terms of electron injection layer, it can be omitted by making a preferred choice of electron transport layer and cathode.

[0111] Furthermore, as materials for the electron injection layer and electron transport layer, products that dope metals such as cesium with N, which are typically used in this layer, can be used.

[0112] Materials used as cathodes for organic EL elements include metals with low work functions such as aluminum, alloys with low work functions such as magnesium-silver alloys, magnesium-calcium alloys, magnesium-indium alloys, and aluminum-magnesium alloys, as well as ITO and IZO.

[0113] As a capping layer for organic EL elements, carbazole compounds represented by the above general formula (I) are preferably used. These can be formed into films individually, or used as monolayers mixed with other materials, or as laminates between individually formed layers, between mixed layers, or between individually formed layers and mixed layers. These materials can be used to form films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0114] The refractive index of the light transmitted during film formation of the carbazole compound represented by the above general formula (I) in the wavelength range of 450 nm to 700 nm is preferably 1.70 or higher, and particularly preferably 1.85 or higher.

[0115] It should be noted that the above description refers to organic EL elements with a top-emitting structure, but the present invention is not limited thereto. It is also applicable to organic EL elements with a bottom-emitting structure and organic EL elements with a dual-emitting structure that emits light from both the top and bottom. In these cases, the electrode in the direction in which light is emitted from the light-emitting element is preferably transparent or semi-transparent.

[0116] Example

[0117] The embodiments of the present invention will be specifically described below through examples. The present invention is not limited to the following examples as long as it does not depart from its spirit.

[0118] [Example 1]

[0119] <Synthesis of Compound (3)>

[0120] 4-{3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxane-2-yl)-9H-carbazole-9-yl} benzonitrile: 7.5 g, 2-chloroquinoxaline: 5.0 g, tetrakis(triphenylphosphine)palladium(0): 1.7 g, potassium carbonate: 10.0 g were loaded into a reaction vessel and refluxed and stirred overnight in a toluene / EtOH / H2O mixed solvent. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using o-dichlorobenzene solvent to obtain compound (3): 5.6 g (yield: 74.1%).

[0121] [Chemistry 3]

[0122]

[0123] The structure of the obtained yellow powder was identified using NMR.

[0124] use 1 H-NMR (CDCl3) detected the following 20 hydrogen signals, confirming it as compound (3).

[0125] δ (ppm) = 9.55 (2H), 9.20 (2H), 8.41 (2H), 8.25 (2H), 8.19 (2H), 8.04 (2H), 7.88-7.78 (6H), 7.66 (2H).

[0126] [Example 2]

[0127] <Synthesis of Compound (13)>

[0128] 8.0 g of 9-(naphthyl-2-yl)-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaneborane-2-yl)-9H-carbazole, 5.1 g of 2-chloroquinoxaline, 1.7 g of tetra(triphenylphosphine)palladium(0), and 10.1 g of potassium carbonate were charged into a reaction vessel and refluxed and stirred overnight in a toluene / EtOH / H2O mixed solvent. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using monochlorobenzene solvent to obtain compound (13): 6.5 g (yield: 80.4%).

[0129] [Chemistry 4]

[0130]

[0131] The structure of the obtained yellow powder was identified using NMR.

[0132] use 1 H-NMR (CDCl3) detected the following 23 hydrogen signals, confirming it as compound (13).

[0133] δ (ppm) = 9.56 (2H), 9.23 (2H), 8.39 (2H), 8.25 (2H), 8.19-8.17 (4H), 8.07-8.00 (2H), 7.84 (2H), 7.78 (3H), 7.67 (4H).

[0134] [Example 3]

[0135] <Synthesis of Compound (56)>

[0136] A reaction vessel was loaded with 5.0 g of 9-(naphthyl-2-yl)-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaneborane-2-yl)-9H-carbazole, 4.6 g of 6-chloro-2-phenyl-quinoxaline, 0.4 g of tris(dibenzylidene)acetone dipalladium(O) (Tricyclohexylphosphine(O)), 0.5 g of tricyclohexylphosphine, and 9.7 g of tripotassium phosphate. The mixture was refluxed and stirred overnight in a 1,4-dioxane / H2O mixed solvent. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using o-dichlorobenzene solvent to obtain compound (56): 4.7 g (yield: 73.0%).

[0137] [Chemistry 5]

[0138]

[0139] The structure of the obtained yellow powder was identified using NMR.

[0140] use 1 H-NMR (CDCl3) detected the following 31 hydrogen signals, confirming it as compound (56).

[0141] δ (ppm) = 9.40 (2H), 8.71 (2H), 8.49 (2H), 8.31 (4H), 8.27 (4H), 8.19-8.17 (2H), 8.05-8.00 (2H), 7.94 (2H), 7.79 (1H), 7.67-7.55 (10H).

[0142] [Example 4]

[0143] <Synthesis of Compound (69)>

[0144] A reaction vessel was loaded with 9.0 g of 9-(naphthyl-2-yl)-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaneborane-2-yl)-9H-carbazole, 8.7 g of 2-(4-chlorophenyl)-quinoxaline, 0.8 g of tris(dibenzyl)acetone dipalladium(0), 0.9 g of tricyclohexylphosphine, and 10.5 g of tripotassium phosphate. The mixture was refluxed and stirred overnight in a 1,4-dioxane / H2O mixed solvent. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using monochlorobenzene solvent to obtain compound (69): 5.7 g (yield: 49.1%).

[0145] [Chemistry 6]

[0146]

[0147] The structure of the obtained yellow powder was identified using NMR.

[0148] use 1 H-NMR (CDCl3) detected the following 31 hydrogen signals, confirming it as compound (69).

[0149] δ (ppm) = 9.45 (2H), 8.60 (2H), 8.39 (4H), 8.22 (2H), 8.17 (4H), 8.05-8.00 (6H), 7.86-7.76 (7H), 7.67-7.61 (4H).

[0150] [Example 5]

[0151] <Synthesis of Compound (6)>

[0152] A reaction vessel was loaded with 11.0 g of 6-(3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxacyclopentaborane-2-yl)-9H-carbazole-9-yl)nicotinonitrile, 7.6 g of 2-chloroquinoxaline, 1.0 g of tetra(triphenylphosphine)palladium(0), and 8.8 g of potassium carbonate. The mixture was refluxed and stirred overnight in a toluene / ethanol / H2O mixed solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (6): 7.5 g (yield: 67.6%).

[0153] [Chemistry 7]

[0154]

[0155] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0156] MS[M+H] + =526

[0157] [Example 6]

[0158] <Synthesis of Compound (10)>

[0159] 10.0 g of 3,6-bis(quinoxolin-2-yl)-9H-carbazole, 7.3 g of 4'-bromo-[1,1'-biphenyl]-4-carboxynitrile, 0.4 g of tris(dibenzylene)acetone dipalladium(0), 0.4 g of Sphos, and 4.5 g of sodium tert-butyl were charged into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (6): 8.0 g (yield: 56.4%).

[0160] [Chemistry 8]

[0161]

[0162] The structure of the obtained yellow powder was identified using NMR.

[0163] use 1 H-NMR (CDCl3) detected the following 24 hydrogen signals, confirming it as compound (10).

[0164] δ (ppm) = 9.55 (2H), 9.20 (2H), 8.39 (2H), 8.23 ​​(2H), 8.16 (2H), 7.93 (2H), 7.84-7.75 (10H), 7.67 (2H).

[0165] [Example 7]

[0166] <Synthesis of Compound (17)>

[0167] 10.0 g of 3,6-bis(quinoxolin-2-yl)-9H-carbazole, 6.4 g of 3-bromodibenzofuran, 0.4 g of tris(dibenzylene)acetone dipalladium(0), 0.4 g of Sphos, and 4.5 g of sodium tert-butyl were charged into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (17): 11.2 g (yield: 80.6%).

[0168] [Chemistry 9]

[0169]

[0170] The structure of the obtained yellow powder was identified using NMR.

[0171] use 1 H-NMR (CDCl3) detected the following 23 hydrogen signals, confirming it as compound (17).

[0172] δ (ppm) = 9.55 (2H), 9.21 (2H), 8.38 (2H), 8.24 (3H), 8.16 (2H), 8.09 (1H) )7.89 (1H), 7.82 (2H), 7.75 (2H), 7.69-7.64 (3H), 7.57 (1H), 7.46 (1H).

[0173] [Example 8]

[0174] <Synthesis of Compound (18)>

[0175] 10.0 g of 3,6-bis(quinoxalo-2-yl)-9H-carbazole, 6.3 g of 2-(4-chlorophenyl)-quinoxaloline, 0.5 g of tris(dibenzylene)acetone dipalladium(0), 0.2 g of tri-tert-butylphosphine, and 4.8 g of tert-butylsodium were charged into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (18): 8.5 g (yield: 57.4%).

[0176] [Chemistry 10]

[0177]

[0178] The structure of the obtained yellow powder was identified using NMR.

[0179] use 1 H-NMR (CDCl3) detected the following 25 hydrogen signals, confirming it as compound (18).

[0180] δ (ppm) = 9.56 (2H), 9.49 (1H), 9.21 (2H), 8.56 (2H), 8.41 (2H), 8.25-8.15 (6H), 7.92-7.71 (9H).

[0181] [Example 9]

[0182] <Synthesis of Compound (35)>

[0183] 3,6-bis(quinoxalo-2-yl)-9H-carbazole: 5.0 g, 2-(4-bromophenyl)-benzothiazole: 6.0 g, copper: 2.1 g, dibenzo-18-crown-6-ether: 0.5 g, potassium carbonate: 3.3 g were loaded into a reaction vessel and stirred under reflux in DMF solvent for two nights. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using monochlorobenzene solvent to obtain compound (35): 4.9 g (yield: 65.6%).

[0184] [Chemistry 11]

[0185]

[0186] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0187] MS[M+H] + =633

[0188] [Example 10]

[0189] <Synthesis of Compound (36)>

[0190] 3,6-bis(quinoxalo-2-yl)-9H-carbazole: 8.0 g, 2-(4-bromophenyl)-benzofuran: 9.1 g, copper: 3.3 g, dibenzo-18-crown-6-ether: 0.6 g, potassium carbonate: 5.2 g were loaded into a reaction vessel and stirred under reflux in DMF solvent for three nights. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (36): 8.6 g (yield: 73.9%).

[0191] [Chemistry 12]

[0192]

[0193] The structure of the obtained yellow powder was identified using NMR.

[0194] use 1 H-NMR (CDCl3) detected the following 25 hydrogen signals, confirming it as compound (36).

[0195] δ (ppm) = 9.55 (2H), 9.20 (2H), 8.39 (2H), 8.25-8.15 (6H), 7.84-7.74 (6H), 7.68 (3H), 7.60 (1H), 7.36 (1H), 7.30 (1H), 7.20 (1H).

[0196] [Example 11]

[0197] <Synthesis of Compound (37)>

[0198] 3,6-bis(quinoxolin-2-yl)-9H-carbazole: 8.0 g, 2-(4-bromophenyl)-thiophene: 6.0 g, tris(dibenzylene)acetone dipalladium(0): 0.4 g, tri-tert-butylphosphine: 0.2 g, and tert-butylsodium: 2.7 g were loaded into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (37): 9.1 g (yield: 76.2%).

[0199] [Chemistry 13]

[0200]

[0201] The structure of the obtained yellow powder was identified using NMR.

[0202] use 1H-NMR (CDCl3) detected the following 25 hydrogen signals, confirming it as compound (37).

[0203] δ (ppm) = 9.55 (2H), 9.20 (2H), 8.39 (2H), 8.23 ​​(2H), 8.16 (2H), 8.04 (2H), 7.90-7.67 (11H), 7.40 (2H).

[0204] [Example 12]

[0205] <Synthesis of Compound (39)>

[0206] 3,6-bis(quinoxalo-2-yl)-9H-carbazole: 8.0 g, 2-(4-bromophenyl)-oxazolopyridine: 9.1 g, copper: 3.3 g, dibenzo-18-crown-6-ether: 0.6 g, potassium carbonate: 5.2 g were loaded into a reaction vessel and stirred under reflux in DMF solvent for two nights. After natural cooling, MeOH / H2O was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (39): 3.0 g (yield: 25.7%).

[0207] [Chemistry 14]

[0208]

[0209] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0210] MS[M+H] + =618

[0211] [Example 13]

[0212] <Synthesis of Compound (54)>

[0213] In a reaction vessel, 4.0 g of (4-(3,6-dibromo-9H-carbazole-9-yl)benzonitrile, 6.9 g of 2-phenyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxacyclopentaborane-2-yl)quinoxaline, 0.4 g of tetra(triphenylphosphine)palladium(0), and 3.9 g of potassium carbonate were added and refluxed and stirred overnight in a toluene / ethanol / H2O mixed solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (54): 4.9 g (yield: 76.6%).

[0214] [Chemistry 15]

[0215]

[0216] The structure of the obtained yellow powder was identified using NMR.

[0217] use 1 H-NMR (CDCl3) detected the following 28 hydrogen signals, confirming it as compound (54).

[0218] δ (ppm) = 9.40 (2H), 8.66 (2H), 8.46 (2H), 8.31-8.24 (8H), 8.01 (2H), 7.94 (2H), 7.86 (2H), 7.65-7.55 (8H).

[0219] [Example 14]

[0220] <Synthesis of Compound (59)>

[0221] 9.0 g of 3,6-dibromo-9-(quinolin-3-yl)-9H-carbazole, 9.6 g of 2-phenyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxane-2-yl)quinoxaline, 0.8 g of tris(dibenzyl)acetone dipalladium(0), 1.0 g of tricyclohexylphosphine, and 11.6 g of tripotassium phosphate were added to a reaction vessel and refluxed and stirred overnight in a 1,4-dioxane / H2O mixed solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using a chlorobenzene / acetone mixed solvent to obtain compound (59): 8.6 g (yield: 68.2%).

[0222] [Chemistry 16]

[0223]

[0224] The structure of the obtained yellow powder was identified using NMR.

[0225] use 1 H-NMR (CDCl3) detected the following 28 hydrogen signals, confirming it as compound (59).

[0226] δ (ppm) = 9.39 (2H), 9.01 (1H), 8.82 (1H), 8.67 (2H), 8.47 (2H), 8.31-8.24 (8H), 8.04 (1H), 7.93 (2H), 7.68-7.53 (9H).

[0227] [Example 15]

[0228] <Synthesis of Compound (60)>

[0229] A reaction vessel was loaded with 9.8 g of 9-(quinolin-3-yl)-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaneborane-2-yl)-9H-carbazole, 9.5 g of 6-chloro-2-phenylquinoxaline, 0.8 g of tris(dibenzylene)acetone dipalladium(0), 1.0 g of tricyclohexylphosphine, and 11.4 g of tripotassium phosphate. The mixture was refluxed and stirred overnight in a 1,4-dioxane / H2O mixed solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using a chlorobenzene / acetone mixed solvent to obtain compound (60): 8.6 g (yield: 68.2%).

[0230] [Chemistry 17]

[0231]

[0232] The structure of the obtained yellow powder was identified using NMR.

[0233] use 1 H-NMR (CDCl3) detected the following 30 hydrogen signals, confirming it as compound (60).

[0234] δ (ppm) = 9.34 (2H), 9.26 (1H), 8.70 (2H), 8.48 (3H), 8.33-8.24 (9H), 8.01 (1H), 7.95 (2H), 7.89 (1H), 7.74 (1H), 7.63-7.53 (8H).

[0235] [Example 16]

[0236] <Synthesis of Compound (71)>

[0237] A reaction vessel was loaded with 9.0 g of 9-(pyridin-3-yl)-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaneborane-2-yl)-9H-carbazole, 2.2 g of 2-(4-chlorophenyl)-quinoxaline, 0.7 g of tris(dibenzylene)acetone dipalladium(0), 1.0 g of tricyclohexylphosphine, and 11.6 g of tripotassium phosphate. The mixture was refluxed and stirred overnight in a 1,4-dioxane / H2O mixed solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using monochlorobenzene solvent to obtain compound (71): 5.9 g (yield: 50.0%).

[0238] [Chemistry 18]

[0239]

[0240] The structure of the obtained yellow powder was identified using NMR.

[0241] use 1 H-NMR (CDCl3) detected the following 28 hydrogen signals, confirming it as compound (71).

[0242] δ (ppm) = 7.52 (2H), 7.65 (1H), 7.75-7.84 (6H), 8.00 (5H), 8.18 (4H), 8.36 (4H), 8.55 (2H), 8.80 (1H), 9.00 (1H), 9.43 (2H).

[0243] [Example 17]

[0244] <Synthesis of Compound (98)>

[0245] 3,6-bis(quinoxolin-2-yl)-9H-carbazole: 9.0 g, 2-(4-chlorophenyl)-pyrimidine: 4.5 g, tris(dibenzylene)acetone dipalladium(0): 0.4 g, Sphos: 0.4 g, and sodium tert-butyl: 4.1 g were loaded into a reaction vessel and refluxed with xylene solvent with stirring overnight. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization with dichlorobenzene solvent to obtain compound (98): 7.4 g (yield: 60.1%).

[0246] [Chemistry 19]

[0247]

[0248] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0249] MS[M+H] + =578

[0250] [Example 18]

[0251] <Synthesis of Compound (99)>

[0252] 3,6-bis(quinoxalo-2-yl)-9H-carbazole: 9.1 g, 2-(3-chlorophenyl)-quinoxaloline: 5.7 g, tris(dibenzylene)acetone dipalladium(0): 0.4 g, Sphos: 0.4 g, and sodium tert-butyl: 4.1 g were loaded into a reaction vessel and refluxed with xylene solvent with stirring overnight. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization with dichlorobenzene solvent to obtain compound (99): 6.8 g (yield: 50.4%).

[0253] [Chemistry 20]

[0254]

[0255] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0256] MS[M+H] + =628

[0257] [Example 19]

[0258] <Synthesis of Compound (100)>

[0259] 3,6-bis(quinoxalo-2-yl)-9H-carbazole: 9.0 g, 2-chloro-quinoxaloline: 4.2 g, tris(dibenzylene)acetone dipalladium(0): 1.0 g, Sphos: 1.3 g, and sodium tert-butyl: 6.1 g were loaded into a reaction vessel and refluxed with xylene solvent with stirring overnight. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization with dichlorobenzene solvent to obtain compound (100): 9.6 g (yield: 81.9%).

[0260] [Chemistry 21]

[0261]

[0262] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0263] MS[M+H] + =552

[0264] [Example 20]

[0265] <Synthesis of Compound (101)>

[0266] 10.0 g of 3,6-bis(quinoxolin-2-yl)-9H-carbazole, 7.2 g of 2-(3-chlorophenyl)-oxazolopyridine, 0.4 g of tris(dibenzylene)acetone dipalladium(0), 0.4 g of Sphos, and 4.5 g of sodium tert-butyl were charged into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (101): 12.1 g (yield: 84.6%).

[0267] [Chemistry 22]

[0268]

[0269] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0270] MS[M+H] + =618

[0271] [Example 21]

[0272] <Synthesis of Compound (102)>

[0273] 10.0 g of 3,6-bis(quinoxolin-2-yl)-9H-carbazole, 6.5 g of 3-(4-chlorophenyl)benzofuran, 1.1 g of tris(dibenzylene)acetone dipalladium(O), 1.5 g of Sphos, and 3.4 g of sodium tert-butyl were charged into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (102): 11.4 g (yield: 78.4%).

[0274] [Chemistry 23]

[0275]

[0276] The structure of the obtained yellow powder was identified using NMR.

[0277] use 1 H-NMR (CDCl3) detected the following 25 hydrogen signals, confirming it as compound (102).

[0278] δ (ppm) = 9.55 (2H), 9.21 (2H), 8.39 (2H), 8.24 (2H), 8.16 (2H), 7.98 (4H), 7.85-7.75 (6H), 7.69 (2H), 7.63 (1H), 7.42 (2H).

[0279] [Example 22]

[0280] <Synthesis of Compound (103)>

[0281] 2-(4-(6-(quinoxolin-2-yl)-9H-carbazole-3-yl)phenyl)oxazolopyridine: 5.6 g, 2-chloroquinoline: 2.1 g, tris(dibenzyl)acetone dipalladium(0): 0.5 g, Sphos: 0.5 g, sodium tert-butyl: 1.6 g were loaded into a reaction vessel and refluxed and stirred overnight in xylene solvent. After natural cooling, MeOH was added, and the precipitated solid was filtered to obtain the crude product. The crude product was purified by recrystallization using dichlorobenzene solvent to obtain compound (103): 4.3 g (yield: 60.1%).

[0282] [Chemistry 24]

[0283]

[0284] The obtained yellow powder was analyzed using LC-MS to determine the same molecular weight.

[0285] MS[M+H] + =618

[0286] [Example 23]

[0287] For the compounds obtained in Examples 1 to 22 above, a high-sensitivity differential scanning calorimeter (Burcal) was used to measure the compounds. The melting point and glass transition temperature (Tg) were determined using an E-E-S (DSC3100SA) microscope. The results are shown in Table 1.

[0288] It should be noted that compounds (18) and (103) have two melting points. This is presumably due to the existence of two crystalline forms with different melting points.

[0289] [Table 1]

[0290]

[0291] The results above show that the compounds obtained in Examples 1-22 have high melting points and either no glass transition temperature or a glass transition temperature above 100°C. This indicates that the thin films are stable and have excellent durability.

[0292] [Example 24]

[0293] Using the compounds obtained in Examples 1 to 22 above, an 80 nm thick vapor-deposited film was formed on a silicon substrate. The refractive index n and extinction coefficient k at wavelengths of 450 nm and 750 nm were measured using a spectrophotometer (Filmetrick, F10-RT-UV) at room temperature (25 ± 2 °C). Furthermore, for comparison, the refractive index n and extinction coefficient k were measured for Alq3 and the comparative compounds (CPL-1) and (CPL-2) with the following structural formulas (see, for example, Patent Documents 4 and 5). The measurement results are summarized in Table 2.

[0294] [Chemistry 25]

[0295]

[0296] [Chemistry 26]

[0297]

[0298] [Table 2]

[0299]

[0300] As shown in Table 2, the carbazole compounds of the present invention have the same extinction coefficient as Alq3 and comparative compounds (CPL-1) and (CPL-2) in the wavelength range of 450 nm to 750 nm, and have a higher refractive index than these compounds. This indicates that by using the carbazole compounds of the present invention as constituent materials of the capping layer, an improvement in the light extraction efficiency in organic EL devices can be expected.

[0301] [Example 25]

[0302] like Figure 10 As shown, an organic EL element is fabricated on a glass substrate 1 on which a reflective ITO electrode is pre-formed as a transparent anode 2. A hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode 8, and a capping layer 9 are sequentially deposited.

[0303] Specifically, for a glass substrate 1, which has been sequentially coated with a 50 nm thick ITO film, a 100 nm thick silver alloy reflective film, and a 5 nm thick ITO film, after ultrasonic cleaning in isopropanol for 20 minutes, it is dried on a hot plate heated to 250°C for 10 minutes. Then, after UV ozone treatment for 2 minutes, the glass substrate with ITO is mounted in a vacuum evaporation machine, and the pressure is reduced to below 0.001 Pa. Next, using a transparent anode 2 as a hole injection layer 3, a binary evaporation process is performed on an electron acceptor (Acceptor-1) and a compound (HTM-1) with the following structural formula at a evaporation rate ratio of Acceptor-1:compound (HTM-1) = 3:97 to form a film thickness of 10 nm.

[0304] On the hole injection layer 3, a compound (HTM-1) with the following structural formula is formed as a hole transport layer 4 with a film thickness of 140 nm. On the hole transport layer 4, a compound (EMD-1) and a compound (EMH-1) with the following structural formula are binary deposited at a deposition rate ratio of (EMD-1): (EMH-1) = 5:95 to form a light-emitting layer 5 with a film thickness of 20 nm. On the light-emitting layer 5, a compound (ETM-1) and a compound (ETM-2) with the following structural formula are binary deposited at a deposition rate ratio of (ETM-1): (ETM-2) = 50:50 to form an electron transport layer 6 with a film thickness of 30 nm. On the electron transport layer 6, lithium fluoride is formed as an electron injection layer 7 with a film thickness of 1 nm. On the electron injection layer 7, a magnesium-silver alloy is formed as a cathode 8 such that the film thickness is 12 nm.

[0305] Finally, the compound (3) of Example 1 was formed as a capping layer 9 with a film thickness of 60 nm. The organic EL element was subjected to characteristic measurements in the atmosphere at room temperature, and the results of the luminescence characteristics under applied DC voltage are summarized in Table 3.

[0306] [Chemistry 27]

[0307]

[0308] [Example 26]

[0309] Except that in Example 25, the compound (13) obtained in Example 2 was used as the capping layer 9 instead of the compound (3) in Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0310] [Example 27]

[0311] Except that in Example 25, the compound (56) obtained in Example 3 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0312] [Example 28]

[0313] Except that in Example 25, the compound (69) obtained in Example 4 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0314] [Example 29]

[0315] Except that in Example 25, the compound (6) obtained in Example 5 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0316] [Example 30]

[0317] Except that in Example 25, the compound (10) obtained in Example 6 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0318] [Example 31]

[0319] Except that in Example 25, the compound (17) obtained in Example 7 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0320] [Example 32]

[0321] Except that in Example 25, the compound (18) obtained in Example 8 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0322] [Example 33]

[0323] Except that in Example 25, the compound (35) obtained in Example 9 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0324] [Example 34]

[0325] Except that in Example 25, the compound (36) obtained in Example 10 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0326] [Example 35]

[0327] Except that in Example 25, the compound (37) obtained in Example 11 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0328] [Example 36]

[0329] Except that in Example 25, the compound (39) obtained in Example 12 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0330] [Example 37]

[0331] Except that in Example 25, the compound (54) obtained in Example 13 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0332] [Example 38]

[0333] Except that in Example 25, the compound (59) obtained in Example 14 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0334] [Example 39]

[0335] Except that in Example 25, the compound (60) obtained in Example 15 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0336] [Example 40]

[0337] Except that in Example 25, the compound (71) obtained in Example 16 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0338] [Example 41]

[0339] Except that in Example 25, the compound (98) obtained in Example 17 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0340] [Example 42]

[0341] Except that in Example 25, the compound (99) obtained in Example 18 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0342] [Example 43]

[0343] Except that in Example 25, the compound (100) obtained in Example 19 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0344] [Example 44]

[0345] Except that in Example 25, the compound (101) obtained in Example 20 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0346] [Example 45]

[0347] Except that in Example 25, the compound (102) obtained in Example 21 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0348] [Example 46]

[0349] Except that in Example 25, the compound (103) obtained in Example 22 was used as the capping layer 9 instead of the compound (3) of Example 1, the organic EL element was fabricated under the same conditions. The characteristics of the fabricated organic EL element were measured in the atmosphere at room temperature, and the results of the measurement of the light emission characteristics with applied DC voltage are summarized in Table 3.

[0350] [Comparative Example 1]

[0351] For comparison, except that Alq3 was used as the capping layer 9 instead of compound (3) in Example 1 in Example 7, organic EL elements were fabricated under the same conditions. The characteristics of the fabricated organic EL elements were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0352] [Comparative Example 2]

[0353] For comparison, except that in Example 7, compound (CPL-1) was used instead of compound (3) in Example 1 as the capping layer 9, organic EL elements were fabricated under the same conditions. The characteristics of the fabricated organic EL elements were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0354] [Comparative Example 3]

[0355] For comparison, except that in Example 7, compound (CPL-2) was used instead of compound (3) in Example 1 as the capping layer 9, organic EL elements were fabricated under the same conditions. The characteristics of the fabricated organic EL elements were measured in the atmosphere at room temperature, and the results of the measurement of the luminescence characteristics with applied DC voltage are summarized in Table 3.

[0356] The results of measuring the device lifetime using the organic EL devices fabricated in the above embodiments and comparative examples are summarized in Table 3. Regarding the device lifetime measured in this invention, as a result of performing a 10 mA / cm... 2 The time it takes for the constant current drive to decay to 95% of the initial brightness when it is set to 100% is measured.

[0357] [Table 3]

[0358]

[0359] As shown in Table 3, the current density is 10 mA / cm². 2 The driving voltage and element lifespan were approximately the same in the elements of Comparative Examples 1-3 and Examples 25-46. However, significant improvements in brightness, luminous efficiency, and power efficiency were observed in the elements of Examples 25-46 compared to the elements of the comparative examples. This indicates that the carbazole compound represented by general formula (I) of the present invention is a suitable material for use as a capping layer, and by increasing the refractive index of the capping layer, the light extraction efficiency of the organic EL element can be significantly improved.

[0360] Industrial availability

[0361] Regarding the carbazole compound of the present invention, its high refractive index significantly improves light extraction efficiency, and the film exhibits stable properties, making it an excellent compound suitable for use in organic EL devices. Furthermore, organic EL devices fabricated using the carbazole compound of the present invention achieve high efficiency. Moreover, the compound of the present invention, which does not absorb in the cyan, green, and red wavelength regions, is particularly suitable for applications requiring high color purity, vividness, and brightness. For example, applications in household appliances and lighting are anticipated.

[0362] Explanation of reference numerals in the attached figures

[0363] 1. Glass substrate

[0364] 2. Transparent anode

[0365] 3. Hole injection layer

[0366] 4. Hole transport layer

[0367] 5. Light-emitting layer

[0368] 6. Electron transport layer

[0369] 7 Electron Injection Layer

[0370] 8 Cathode

[0371] 9. Covering layer

Claims

1. A carbazole compound represented by the following general formula (I), In the formula, A, B, and C each independently represent a substituted or unsubstituted monovalent aryl group, or a substituted or unsubstituted monovalent heteroaryl group. However, C is not benzoxazolyl, and at least two of A, B, and C represent substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinoxalinyl groups. L1 to L3 each independently represent a single bond, an unsubstituted divalent aryl group, or an unsubstituted divalent heteroaryl group.

2. The carbazole compound according to claim 1, which is represented by the following general formula (II), In the formula, A, B, C and L1 to L3 are as defined in the general formula (I).

3. The carbazole compound according to claim 2, wherein, In the general formula (II), L1 to L3 are each independently a single bond, an unsubstituted phenylene, an unsubstituted pyridylene, or an unsubstituted naphthylene.

4. The carbazole compound according to claim 3, wherein, In the general formula (II), A and B, or A and C, are each independently substituted or unsubstituted quinoxalinyl or substituted or unsubstituted quinoxalinyl.

5. The carbazole compound according to claim 4, wherein, In the general formula (II), L1 and L2 are single bonds. A and B are each independently substituted quinoxalinyl or substituted quinazolinyl.

6. The carbazole compound according to claim 5, wherein, In the general formula (II), A and B are each independently substituted 6-quinoxalinyl or substituted 6-quinoxalinyl.

7. The carbazole compound according to claim 4, wherein, In the general formula (II), L1 and L2 are single bonds, and A and B are each independently an unsubstituted quinoxalinyl group or an unsubstituted quinazolinyl group, or In the general formula (II), L1 and L3 are single bonds, and A and C are each independently an unsubstituted quinoxalinyl or an unsubstituted quinazolinyl.

8. The carbazole compound according to claim 7, wherein, In the general formula (II), A and B are each independently unsubstituted 2-quinoxalinyl or unsubstituted 2-quinoxalinyl.

9. The carbazole compound according to claim 4, wherein, In the general formula (II), L1 and L2 are each independently an unsubstituted phenylene, an unsubstituted pyridylene, or an unsubstituted naphthylene. A and B are each independently an unsubstituted quinoxalinyl group or an unsubstituted quinazolinyl group.

10. The carbazole compound according to claim 7, wherein, In the general formula (II), A and B are each independently unsubstituted 2-quinoxalinyl or unsubstituted 2-quinoxalinyl.

11. The carbazole compound according to claim 2, wherein, In the general formula (II), C is naphthyl, cyanophenyl, pyridyl, quinolinyl, quinoxalinyl, quinazolinyl, benzothiazolyl, or oxazolopyridyl.

12. The carbazole compound according to claim 11, wherein, In the general formula (II), C is 2-naphthyl, 4-cyanophenyl, 3-pyridyl, 4-pyridyl, 2-quinolinyl, 3-quinolinyl, 6-quinolinyl, 7-quinolinyl, 2-quinoxalinyl, 6-quinoxalinyl, 2-quinazolinyl, 6-quinazolinyl, 7-quinazolinyl, 2-benzothiazolyl, or 2-oxazolopyridyl.

13. An organic electroluminescent element, comprising at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a capping layer, wherein, The capping layer contains the carbazole compound according to any one of claims 1 to 12.

14. The organic electroluminescent element according to claim 13, wherein, The refractive index of the vapor-deposited film obtained by vacuum evaporation of the carbazole compound according to any one of claims 1 to 12 on a silicon substrate with a film thickness of 80 nm, measured at room temperature (25 ± 2 °C), is 1.70 or higher at a wavelength of 450 nm or more and 750 nm or less.

15. The organic electroluminescent element according to claim 13, wherein, The capping layer is a laminate or mixture containing two or more compounds, and at least one of the compounds is a carbazole compound as described in any one of claims 1 to 12.

16. An electronic device or electronic component having a pair of electrodes and at least one organic layer sandwiched therebetween, wherein, The compound containing any one of claims 1 to 12.

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