Heterocyclic compounds and organic electroluminescent elements, electronic devices

Abstract

The object of the present invention is to provide a compound with a high refractive index in the wavelength range of 450 nm to 750 nm in the capping layer in order to improve the light extraction efficiency of organic EL elements. [Solution] This invention focuses on the fact that heterocyclic compounds exhibit excellent stability and durability in thin films, and that the refractive index can be improved by adjusting the molecular structure. By designing molecules and using them as materials to constitute the capping layer, an organic EL element with excellent luminescence efficiency was obtained.

Description

[Technical Field]

[0001] The present invention relates to self-emissive electronic elements suitable for various display devices, particularly organic electroluminescent elements (hereinafter abbreviated as organic EL elements), or heterocyclic compounds suitable for electronic devices, and to organic EL elements or electronic devices using said heterocyclic compounds. [Background technology]

[0002] In 1987, CWTang et al. at Eastman Kodak made organic light-emitting diodes (OLEDs) practical by developing a multilayer structure in which various roles were assigned to different materials. They layered a phosphor capable of transporting electrons with an organic material capable of transporting holes, and injected both charges into the phosphor layer to cause light emission, achieving 1000 cd / m² at voltages of 10V or less. 2 The above high brightness levels can now be achieved (see Patent Documents 1 and 2).

[0003] To date, many improvements have been made to commercialize organic EL elements, and the various roles of the stacked structure have been further subdivided. In electroluminescent elements where an anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode are sequentially arranged on a substrate, high efficiency and durability have been achieved by light-emitting elements with a bottom emission structure that emits light from the bottom (see, for example, Non-Patent Document 1).

[0004] In recent years, light-emitting devices with a top-emission structure, which use a metal with a high work function as the anode and emit light from the top, have come into use. In bottom-emission structures, where light is extracted from the bottom where the pixel circuit is located, the area of ​​the light-emitting part is limited. In contrast, top-emission light-emitting devices have the advantage of a wider light-emitting part because the pixel circuit does not obstruct the light as it is extracted from the top. In top-emission light-emitting devices, translucent electrodes such as LiF / Al / Ag (see, for example, Non-Patent Document 2), Ca / Mg (see, for example, Non-Patent Document 3), and LiF / MgAg are used as cathodes.

[0005] In such light-emitting devices, when light emitted from the light-emitting layer is incident on another film, if it is incident at an angle greater than a certain degree, it undergoes total internal reflection at the interface between the light-emitting layer and the other film. As a result, only a portion of the emitted light can be utilized. In recent years, in order to improve the light extraction efficiency, light-emitting devices have been proposed in which a high refractive index "capping layer" is provided on the outside of a low refractive index semi-transparent electrode (see, for example, Non-Patent Documents 2 and 3).

[0006] In light-emitting devices with a top-emission structure, the effect of the capping layer was observed in a light-emitting device using Ir(ppy)3 as the light-emitting material. While the current efficiency was 38 cd / A without a capping layer, a light-emitting device using ZnSe with a 60 nm film thickness as a capping layer achieved an efficiency improvement of approximately 1.7 times, reaching 64 cd / A. Furthermore, it has been shown that the maximum transmittance points of the translucent electrode and capping layer do not necessarily coincide with the maximum efficiency points, indicating that the point of maximum light extraction efficiency is determined by interference effects (see, for example, Non-Patent Document 3).

[0007] Conventionally, the use of a highly detailed metal mask has been proposed for forming the capping layer. However, when used under high-temperature conditions, the metal mask becomes distorted by heat, resulting in a decrease in alignment accuracy. Therefore, since ZnSe has a high melting point of over 1100°C (see, for example, Non-Patent Document 3), it cannot be deposited in the correct position using a highly detailed metal mask, potentially affecting the light-emitting element itself. Furthermore, even with film deposition by sputtering, it can affect the light-emitting element, making capping layers composed of inorganic materials unsuitable for use.

[0008] Furthermore, when using tris(8-hydroxyquinoline)aluminum (Alq3) as a capping layer to adjust the refractive index (see, for example, Non-Patent Document 2), Alq3 is known as an organic EL material commonly used as a green light-emitting material or electron transport material. However, because it has weak absorption around 450 nm, which is used for blue light-emitting materials, there were problems such as a decrease in color purity and a decrease in light extraction efficiency in the case of blue light-emitting elements.

[0009] To improve the characteristics of organic EL elements and to significantly improve light extraction efficiency, there is a need for capping layer materials that have a high refractive index, a low extinction coefficient, and excellent thin-film stability and durability. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 8-048656 [Patent Document 2] Patent No. 3194657 [Non-patent literature]

[0011] [Non-Patent Document 1] Proceedings of the 9th Workshop of the Japan Society of Applied Physics, pp. 55-61 (2001) [Non-Patent Document 2] Appl.Phys.Let.,78,544(2001) [Non-Patent Document 3] Appl.Phys.Let.,82,466(2003) [Overview of the project] [Problems that the invention aims to solve]

[0012] An object of the present invention is to provide a compound having a high refractive index in the range of 450 nm to 750 nm for light transmitted through a capping layer (organic thin film) of an organic EL element and having no absorption near 450 nm. Further, an object is to provide an organic EL element, an electronic device, or an electronic component that improves the light extraction efficiency by using the compound.

[0013] Physical properties of the compound constituting the capping layer (organic thin film) suitable for the present invention include: (1) high refractive index, (2) being capable of evaporation, (3) stable in a thin film state, and (4) high glass transition temperature. Physical properties of the device suitable for the present invention include: (1) high light extraction efficiency, (2) no decrease in color purity, (3) transmitting light without change over time, and (4) long lifespan.

Means for Solving the Problems

[0014] In order to achieve the above object, the inventors of the present invention focused on the fact that heterocyclic compounds are excellent in the stability and durability of thin films and the refractive index value can be improved by adjusting the molecular structure. They designed molecules, fabricated an organic EL element using the heterocyclic compound as a material constituting the capping layer, and intensively evaluated the characteristics of the element. As a result, the present invention was completed.

[0015] That is, according to the present invention, the following heterocyclic compound and organic EL element are provided.

[0016] 1) A heterocyclic compound represented by the following general formula (1).

[0017]

Chemical formula

[0018] (In the formula, X1 and X2 may be the same or different from each other, and represent a nitrogen atom or a CH group, with at least one being a nitrogen atom. L1 and L2 may be the same or different from each other, and represent a divalent group of an aromatic hydrocarbon with 6 to 18 single-bonded, substituted or unsubstituted ring-forming carbon atoms, or a divalent group of an aromatic heterocycle with 5 to 18 substituted or unsubstituted ring-forming carbon atoms. Ar1 and Ar2 may be the same or different from each other, and represent a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocycle group.)

[0019] 2) The heterocyclic compound described in 1) above, wherein the heterocyclic compound is represented by the following general formula (1-a).

[0020] [ka] (1-a)

[0021] (In the formula, L1, L2, Ar1, and Ar2 are as defined in the general formula (1) above.)

[0022] 3) The heterocyclic compound described in 1) above, wherein the heterocyclic compound is represented by the following general formula (1-b).

[0023] [ka] (1-b)

[0024] (In the formula, L1, L2, Ar1, and Ar2 are as defined in the general formula (1) above.)

[0025] 4) The heterocyclic compound according to any one of 1) to 3) above, characterized in that, in general formula (1), general formula (1-a), or general formula (1-b), at least one of L1 and L2 is a divalent group obtained by removing two hydrogen atoms from a single bonded, substituted or unsubstituted benzene, a divalent group obtained by removing two hydrogen atoms from a substituted or unsubstituted biphenyl, or a divalent group obtained by removing two hydrogen atoms from a substituted or unsubstituted naphthalene.

[0026] 5) A heterocyclic compound according to any one of 1) to 3) above, wherein in the general formula (1), general formula (1-a), or general formula (1-b), at least one of L1 and L2 is represented by the following general formula (2).

[0027] [ka] (2)

[0028] (In the formula, R1 to R4 represent a hydrogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyloxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 ring-forming carbon atoms.)

[0029] 6) An organic thin film containing a heterocyclic compound as described in any of 1) to 5) above, characterized in that the refractive index in the wavelength range of 450 nm to 750 nm is 1.70 or higher.

[0030] 7) 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 this order, wherein the capping layer is the organic thin film described in 6) above.

[0031] 8) An electronic device or electronic element having a pair of electrodes and at least one organic layer sandwiched between them, characterized in that the heterocyclic compound described in any of 1) to 5) above is used as a constituent material in the organic layer.

[0032] In the present invention, the term "substituted or unsubstituted" specifically refers to: cyano groups, nitro groups, halogen atoms; alkyl groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, neopentyl groups, and n-hexyl groups; alkyl groups having 1 to 6 carbon atoms, such as methyloxy groups, ethyloxy groups, n-propyloxy groups, isopropyloxy groups, n-butyloxy groups, isobutyloxy groups, tert-butyloxy groups, n-pentyloxy groups, isopentyloxy groups, neopentyloxy groups, and n-hexyloxy groups; phenyl groups, biphenyl groups, terphenyl groups, naphthyl groups, anthracenyl groups, and phenyl groups. Examples of aromatic hydrocarbon groups include nanthrenyl, fluorenyl, spirobifluorenyl, indenyl, pyrenyl, perilenyl, fluoranthenyl, and triphenylenyl groups; and aromatic heterocyclic groups include pyridyl, pyrimidinyl, triazinyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, naphthylidinyl, phenanthrolinyl, acridinyl, carbolinyl, benzoxazolyl, benzothiazolyl, and phenoxadinyl groups, and these substituents may be further substituted with the "substituents" exemplified above. In the present invention, among the "substituents" exemplified above, cyano groups, nitro groups, halogen atoms, alkyl groups having 1 to 3 carbon atoms, alkyloxy groups having 1 to 3 carbon atoms, phenyl groups, naphthyl groups, and quinolyl groups are preferably used.

[0033] In general formula (1), the "divalent groups of substituted or unsubstituted aromatic hydrocarbons with 6 to 18 ring-forming carbon atoms" represented by L1 and L2 can be specifically exemplified by "benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, and fluorene." Furthermore, in the general formula (1), the "divalent group of aromatic hydrocarbons having 6 to 18 substituted or unsubstituted ring-constituting carbon atoms" represented by L1 and L2 refers to a divalent group formed by removing two hydrogen atoms from the above-mentioned "aromatic hydrocarbon." Here, the "divalent group of aromatic hydrocarbons" mentioned above is preferably a divalent group (phenylene group) obtained by removing two hydrogen atoms from benzene, a divalent group obtained by removing two hydrogen atoms from biphenyl, or a divalent group obtained by removing two hydrogen atoms from naphthalene, and more preferably a divalent group (phenylene group) obtained by removing two hydrogen atoms from benzene or a divalent group obtained by removing two hydrogen atoms from naphthalene. Furthermore, as the divalent group (phenylene group) formed by removing two hydrogen atoms from benzene, it is preferable to use a divalent group (1,4-phenylene group) formed by removing two hydrogen atoms from the 1,4-positions of benzene, or a divalent group (1,3-phenylene group) formed by removing two hydrogen atoms from the 1,3-positions of benzene. Furthermore, as a divalent group formed by removing two hydrogen atoms from biphenyl, a divalent group formed by removing two hydrogen atoms from the 4,4'- positions of biphenyl is preferred. Furthermore, as a divalent group formed by removing two hydrogen atoms from naphthalene, a divalent group formed by removing two hydrogen atoms from the 1,4-positions of naphthalene is preferred.

[0034] Examples of "aromatic heterocycles" in the "divalent groups of substituted or unsubstituted aromatic heterocycles with 5 to 18 ring constituent atoms" represented by L1 and L2 in general formula (1) include pyridine, pyrimidine, furan, pyrrole, thiophene, quinoline, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene, and phenanthroline. Furthermore, in the general formula (1), the "divalent group of an aromatic heterocycle having 5 to 18 substituted or unsubstituted ring constituent atoms" represented by L1 and L2 refers to a divalent group formed by removing two hydrogen atoms from the above-mentioned "aromatic heterocycle".

[0035] In general formula (1), the "substituted or unsubstituted aromatic hydrocarbon groups" represented by Ar1 and Ar2 can specifically include phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenantrenyl, fluorenyl, spirobifluorenyl, indenyl, pyrenyl, perilenyl, fluoranthenyl, and triphenylenyl groups.

[0036] In general formula (1), the "substituted or unsubstituted aromatic heterocyclic groups" represented by Ar1 and Ar2 can specifically include pyridyl, pyrimidinyl, triazinyl, furyl, pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, naphthylidinyl, phenanthrolinyl, acridinyl, carbonyl, benzoxazolyl, benzothiazolyl, and phenoxazinyl groups.

[0037] In general formula (2), the "substituted or unsubstituted alkyl groups having 1 to 6 carbon atoms" represented by R1 to R4 can specifically include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and n-hexyl groups.

[0038] In general formula (2), the "substituted or unsubstituted alkyloxy groups having 1 to 6 carbon atoms" represented by R1 to R4 can specifically include methyloxy group, ethyloxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, isobutyloxy group, tert-butyloxy group, n-pentyloxy group, isopentyloxy group, neopentyloxy group, n-hexyloxy group, and others.

[0039] In general formula (2), the "substituted or unsubstituted aromatic hydrocarbon groups with 6 to 12 ring-forming carbon atoms" represented by R1 to R4 can specifically include phenyl groups, biphenyl groups, naphthyl groups, and the like.

[0040] The heterocyclic compound represented by the general formula (1) of the present invention preferably has a refractive index of 1.70 or higher, more preferably 1.80 or higher, and even more preferably 1.85 or higher in the wavelength range of 450 nm to 750 nm. The heterocyclic compound represented by the general formula (1) of the present invention is preferably a heterocyclic compound represented by (1-a) or (1-b). Furthermore, in general formula (1), general formula (1-a), or general formula (1-b), it is preferable that at least one of L1 and L2 is a divalent group represented by general formula (2). In general formula (2), R1 to R4 are preferably hydrogen atoms, and it is more preferable that all of R1 to R4 are hydrogen atoms.

[0041] In the organic EL element of the present invention, the thickness of the capping layer is preferably in the range of 30 nm to 120 nm, and more preferably in the range of 40 nm to 80 nm.

[0042] Furthermore, in the organic EL element of the present invention, the capping layer may be made by stacking or mixing two or more different constituent materials.

[0043] Furthermore, in the organic EL element of the present invention, the refractive index of the capping layer is preferably 1.70 or higher, more preferably 1.80 or higher, and even more preferably 1.85 or higher, when the wavelength of light transmitted through the capping layer is in the range of 450 nm to 750 nm. [Effects of the Invention]

[0044] The heterocyclic compound of the present invention, when used in a capping layer with a higher refractive index than the transparent or translucent electrodes provided outside the transparent or translucent electrodes of an organic EL element, makes it possible to obtain an organic EL element that can significantly improve the light extraction efficiency.

[0045] Furthermore, the heterocyclic compounds of the present invention can be used not only in organic EL elements, but also in electronic equipment fields such as electrophotographic photoreceptors, image sensors, photoelectric conversion elements, and solar cells. [Brief explanation of the drawing]

[0046] [Figure 1] This figure shows the structural formulas of compounds (1-1) to (1-16) as heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 2] This figure shows the structural formulas of compounds (1-17) to (1-34), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 3] This figure shows the structural formulas of compounds (1-35) to (1-50), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 4] This figure shows the structural formulas of compounds (1-51) to (1-68), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 5] This figure shows the structural formulas of compounds (1-69) to (1-82), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 6] This figure shows the structural formulas of compounds (1-83) to (1-96), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 7]This figure shows the structural formulas of compounds (1-97) to (1-110), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 8] This figure shows the structural formulas of compounds (1-111) to (1-124), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 9] This figure shows the structural formulas of compounds (1-125) to (1-138), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 10] This figure shows the structural formulas of compounds (1-139) to (1-152), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 11] This figure shows the structural formulas of compounds (1-153) to (1-155), which are heterocyclic compounds represented by the general formula (1) of the present invention. [Figure 12] This figure shows the organic EL element configurations of Examples 21-38 and Comparative Examples 1-2. [Modes for carrying out the invention]

[0047] The heterocyclic compounds represented by general formula (1) of the present invention are novel compounds, but these compounds can themselves be synthesized according to known methods.

[0048] Specific examples of heterocyclic compounds represented by the general formula (1) of the present invention are shown in Figures 1 to 11, but the invention is not limited to these compounds.

[0049] The method for producing the heterocyclic compound represented by general formula (1) of the present invention is not particularly limited, but the purification of the compound can be carried out by known methods used for the purification of organic compounds, such as purification by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., and recrystallization or crystallization with a solvent, and finally purification by sublimation or the like. The compound can be identified by NMR analysis or the like. It is preferable to measure the melting point, glass transition temperature (Tg), and refractive index as physical properties.

[0050] The melting point and glass transition temperature (Tg) can be measured, for example, using a powder with a high-sensitivity differential scanning calorimeter (Bruker AXS, DSC3100SA).

[0051] The refractive index can be measured by fabricating an 80 nm thin film on a silicon substrate and using a spectroscopic measurement device (F10-RT-UV, manufactured by Filmetrics).

[0052] Examples of the structure of the organic EL element of the present invention include, for example, a light-emitting element with a top emission structure consisting of an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer sequentially on a glass substrate, as well as a structure having a hole injection layer between the anode and the hole transport layer, an electron blocking layer between the hole transport layer and the light-emitting layer, a hole blocking layer between the light-emitting layer and the electron transport layer, and an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, it is possible to omit or combine several organic layers. For example, a configuration in which the hole injection layer and hole transport layer are combined, a configuration in which the hole transport layer and electron blocking layer are combined, a configuration in which the hole blocking layer and electron transport layer are combined, and a configuration in which the electron transport layer and electron injection layer are combined. It is also possible to have a configuration in which two or more organic layers having the same function are stacked. For example, a configuration in which two hole transport layers are stacked, two light-emitting layers are stacked, two electron transport layers are stacked, and two capping layers are stacked.

[0053] The total thickness of each layer of the organic EL element is preferably around 200 nm to 750 nm, and more preferably around 350 nm to 600 nm. The thickness of the capping layer is preferably, for example, 30 nm to 120 nm, and more preferably 40 nm to 80 nm. In this case, good light extraction efficiency can be obtained. The thickness of the capping layer can be appropriately changed depending on the type of light-emitting material used for the light-emitting element, the thickness of each layer of the organic EL element other than the capping layer, etc.

[0054] For the anode of the organic EL element of the present invention, electrode materials with a large work function, such as ITO or gold, are used.

[0055] As the hole injection layer of the organic EL element of the present invention, materials such as arylamine compounds having a structure in which two or more triphenylamine structures are linked in the molecule by single bonds or divalent groups that do not contain heteroatoms, such as benzidine derivatives, starburst-type triphenylamine derivatives, and various triphenylamine tetramers are preferred. In addition, porphyrin compounds represented by copper phthalocyanine, acceptor-type heterocyclic compounds such as hexacyanoazatriphenylene, and coating-type polymer materials can be used. These may be deposited as films on their own, or as monolayers deposited by mixing them with other materials. They may also be used in laminated structures of layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet.

[0056] As the hole transport layer of the organic EL device of the present invention, it is preferable to use benzidine derivatives such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (NPD), N,N,N',N'-tetrabiphenylylbenzidine, 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane (TAPC), and especially arylamine compounds having a structure in which two triphenylamine structures are linked by single bonds or divalent groups that do not contain heteroatoms, such as N,N,N',N'-tetrabiphenylylbenzidine. It is also preferable to use arylamine compounds having only one triphenylamine structure in the molecule, or arylamine compounds having a structure in which three or more triphenylamine structures are linked by single bonds or divalent groups that do not contain heteroatoms, such as various triphenylamine trimers and tetramers. These materials may be deposited individually, or they may be used as single layers formed by mixing them with other materials. They may also be used in laminated structures, such as layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing. Furthermore, a coating-type polymer material such as poly(3,4-ethylenedioxythiophene) (PEDOT) / poly(styrene sulfonate) (PSS) can be used as the hole injection / transport layer. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0057] Furthermore, in the hole injection layer or hole transport layer, it is preferable to further dope the material commonly used in the layer with trisbromophenylamine hexachloroantimony, radialene derivatives, etc. Also, polymer compounds having the structure of benzidine derivatives such as TPD as a substructure can be used.

[0058] As the electron blocking layer of the organic EL device of the present invention, compounds having electron blocking properties can be used, such as carbazole derivatives such as 4,4',4''-tri(N-carbazolyl)triphenylamine (TCTA), 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene, 1,3-bis(carbazole-9-yl)benzene (mCP), and 2,2-bis(4-carbazole-9-yl-phenyl)adamantane (Ad-Cz), and compounds having a triphenylsilyl group and a triarylamine structure, represented by 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene. These may be deposited individually, or used as a single layer by mixing them with other materials. They may also be used in a laminated structure of layers deposited individually, layers deposited by mixing them, or layers deposited individually and layers deposited by mixing them. These materials can be formed into thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0059] As the light-emitting layer of the organic EL element of the present invention, in addition to metal complexes of quinolinol derivatives such as Alq3, various metal complexes, anthracene derivatives, bis-styrylbenzene derivatives, pyrene derivatives, oxazole derivatives, poly(p-phenylenevinylene) derivatives, etc., can be used. The light-emitting layer may also be composed of a host material and a dopant material. Anthracene derivatives are preferably used as the host material, but in addition to the above-mentioned light-emitting materials, heterocyclic compounds having an indole ring as a substructure of the fused ring, heterocyclic compounds having a carbazole ring as a substructure of the fused ring, carbazole derivatives, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc., can be used. As the dopant material, quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, etc., can be used. These materials may be deposited individually, or they may be used as single layers deposited by mixing them with other materials. They may also be used in a laminated structure consisting of layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing.

[0060] Furthermore, phosphorescent materials can be used as light-emitting materials. As phosphorescent materials, metal complex phosphorescent materials such as iridium and platinum can be used. Green phosphorescent materials such as Ir(ppy)3, blue phosphorescent materials such as Firpic and Fir6, and red phosphorescent materials such as Btp2Ir(acac) are used. As the host material in this case, carbazole derivatives such as 4,4'-di(N-carbazolyl)biphenyl (CBP), TCTA, and mCP can be used as hole-injection and transport host materials. As electron-transport host materials, p-bis(triphenylsilyl)benzene (UGH2) and 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (TPBI) can be used, and high-performance organic EL devices can be fabricated.

[0061] To avoid concentration quenching, it is preferable to dope the phosphorescent luminescent material onto the host material by co-deposition in an amount ranging from 1 to 30 weight percent of the entire luminescent layer.

[0062] Furthermore, it is possible to use materials that emit delayed fluorescence as luminescent materials. These materials can be formed into thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0063] As the hole-blocking layer of the organic EL device of the present invention, compounds having hole-blocking properties can be used, such as phenanthroline derivatives like bathocuproine (BCP), metal complexes of quinolinol derivatives like aluminum(III) bis(2-methyl-8-quinolinate)-4-phenylphenolate (BAlq), various rare earth complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, and benzoazole derivatives. These materials may also serve as the electron transport layer material. These materials may be deposited individually, or used as monolayers formed by mixing them with other materials. They may also be used in laminated structures, such as layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0064] As the electron transport layer of the organic EL device of the present invention, metal complexes of quinolinol derivatives such as Alq3 and BAlq, as well as various metal complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, pyridine derivatives, benzimidazole derivatives, benzoazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridoindole derivatives, phenanthroline derivatives, silole derivatives, etc., can be used. These may be deposited as films on their own, or as monolayers deposited by mixing them with other materials. They may also be used in laminated structures of layers deposited individually, layers deposited by mixing, or layers deposited individually and layers deposited by mixing. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0065] As the electron injection layer of the organic EL element of the present invention, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal complexes of quinolinol derivatives such as lithium quinolinol, metal oxides such as aluminum oxide, or metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), and cesium (Cs) can be used, but these can be omitted in the preferred selection of the electron transport layer and cathode.

[0066] Furthermore, in the electron injection layer or electron transport layer, a material that is further doped with a metal such as cesium can be used in addition to the material normally used in the layer.

[0067] As the cathode of the organic EL element of the present invention, electrode materials with a low work function such as aluminum, or alloys with an even lower work function such as magnesium-silver alloy, magnesium-calcium alloy, magnesium-indium alloy, aluminum-magnesium alloy, or materials like ITO and IZO can be used.

[0068] It is preferable to use a heterocyclic compound represented by the general formula (1), (1-a), or (1-b) as the capping layer of the organic EL element of the present invention. These materials can be formed into thin films by known methods such as spin coating or inkjet, in addition to vapor deposition.

[0069] Although the above describes an organic EL element with a top emission structure, the present invention is not limited to this, and can be similarly applied to organic EL elements with a bottom emission structure, and organic EL elements with a dual emission structure that emit light from both the top and bottom. In these cases, the electrodes in the direction from which light is extracted from the light-emitting element must be transparent or semi-transparent. [Examples]

[0070] The embodiments of the present invention will be described in detail below with reference to examples, but the present invention is not limited to the following embodiments unless it exceeds the gist of the invention.

[0071] [Example 1] <2,5-Bis{4-(phenanthrene-9-yl)phenyl}pyrimidine; Synthesis of compounds (1-7)> In a nitrogen-purged reaction vessel, 5.0 g of 2,5-dichloropyrimidine, 50 mL of 1,4-dioxane, 28.1 g of 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborolane, followed by 21.4 g of tripotassium phosphate dissolved in 15 mL of purified water, were sequentially added, and the mixture was bubbling with nitrogen for 30 minutes. Then, 1.5 g of trisdibenzylideneacetone dipalladium and 1.9 g of tricyclohexylphosphine were added, and the mixture was stirred under reflux for 12 hours. After cooling to room temperature, 50 mL of methanol was added, and the precipitated solid was collected by filtration. 1.0 L of chlorobenzene was added to the solid, and the mixture was heated to 100°C to dissolve the solid. Then, 10 g of silica gel and 10 g of activated clay were added, and the mixture was stirred for 1 hour. Insoluble matter was removed by thermal filtration, and the filtrate was concentrated. By recrystallizing the residue with chlorobenzene, 12.6 g (yield: 64%) of a white powder of 2,5-bis{4-(phenanthren-9-yl)phenyl}pyrimidine; compounds (1-7) was obtained.

[0072] [ka] (1-7)

[0073] The structure of the obtained white powder was identified using NMR. 1 The following 28 hydrogen signals were detected by 1H-NMR (THF-d8). δ(ppm)=9.33(2H), 8.80-8.94(6H), 7.99-8.06(6H), 7.60-7.85(14H).

[0074] [Example 2] <2,5-Bis{4-(phenanthrene-9-yl)phenyl}pyridine; Synthesis of compound (1-41)> In Example 1, the same procedure was carried out by substituting 2,5-dichloropyrimidine with 2,5-dibromopyridine to obtain 11.5 g (yield: 78%) of 2,5-bis{4-(phenanthren-9-yl)phenyl}pyridine; compound (1-41) as a white powder.

[0075] [ka] (1-41)

[0076] The structure of the obtained white powder was identified using NMR. 1 The following 29 hydrogen signals were detected by 1H-NMR (THF-d8). δ(ppm)=9.14(1H), 8.81-8.89(4H), 8.39-8.41(2H), 8.22-8.23(1H), 8.12-8.14(1H), 7.95-8.01(6H), 7.80(2H), 7.56-7.79(12H).

[0077] [Example 3] <5-{4-(dibenzofuran-3-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine; synthesis of compound (1-71)> In a nitrogen-purged reaction vessel, 9.4 g of 2,5-dichloropyrimidine, 160 mL of toluene, 60 mL of ethanol, 20.0 g of 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborolane, followed by 10.9 g of potassium carbonate dissolved in 40 mL of purified water, were sequentially added, and the mixture was bubbling with nitrogen for 30 minutes. Then, 0.6 g of tetrakis(triphenylphosphine)palladium(0) was added, and the mixture was stirred under reflux for 15 hours. After cooling to room temperature, the mixture was separated. The organic layer was sequentially washed with water and saturated brine, and then dried over anhydrous magnesium sulfate. The drying agent was removed by filtration, and the filtrate was concentrated. 200 mL of toluene was added to the residue, and after heating to 80°C, 10 g of silica gel and 10 g of activated clay were added, and the mixture was stirred for 1 hour. Insoluble matter was removed by filtration, and the filtrate was concentrated. Acetone was added to the residue and the mixture was dispersed and washed to obtain 16.5 g of a white powder of 5-chloro-2-{4-(phenanthren-9-yl)phenyl}pyrimidine (yield: 86%).

[0078] 8.0 g of the obtained 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine was added to a nitrogen-purged reaction vessel, followed by 100 mL of 1,4-dioxane, 28.1 g of 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}dibenzofuran, and then a solution of 21.4 g of tripotassium phosphate dissolved in 15 mL of purified water, and the mixture was bubbling with nitrogen for 30 minutes. Then, 0.2 g of trisdibenzylideneacetone dipalladium and 0.1 g of tricyclohexylphosphine were added, and the mixture was stirred under reflux for 13 hours. After cooling to room temperature, the precipitated solid was collected by filtration. Methanol and water were added to the solid, and the mixture was dispersed under reflux for 1 hour. The solid was collected, 750 mL of chlorobenzene was added, and the mixture was heated to 100°C to dissolve the solid. Then, 8 g of silica gel and 8 g of activated clay were added, and the mixture was stirred for 1 hour. The insoluble matter was removed by thermal filtration, and the filtrate was concentrated. The residue was recrystallized with chlorobenzene to obtain 10.5 g (yield: 72%) of 5-{4-(dibenzofuran-3-yl)phenyl}-2-{4-(phenanthren-9-yl)phenyl}pyrimidine; compound (1-71) as a white powder.

[0079] [ka] (1-71)

[0080] The structure of the obtained white powder was identified using NMR. 1 The following 26 hydrogen signals were detected by 1H-NMR (THF-d8). δ(ppm)=9.28(2H), 8.76-8.92(4H), 7.96-8.18(9H), 7.36-7.86(11H).

[0081] [Example 4] <5-{4-(phenanthrene-2-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine; synthesis of compound (1-74)> In Example 3, the same procedure was carried out by substituting 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}dibenzofuran with 4,4,5,5-tetramethyl-2-{4-(phenanthrene-2-yl)phenyl}-1,3,2-dioxaborolan to obtain 8.6 g (yield: 58%) of the white powder 5-{4-(phenanthrene-2-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine; compound (1-74).

[0082] [ka] (1-74)

[0083] The structure of the obtained white powder was identified using NMR. 1 The following 28 hydrogen signals were detected by 1H-NMR (THF-d8). δ(ppm)=9.31(2H), 8.78-8.93(6H), 8.35-8.36(1H), 7.91-8.13(9H), 7.85-7.87(2H), 7.60-7.76(8H).

[0084] [Example 5] <2-{4-(phenanthrene-9-yl)phenyl}-5-{4-(1,10-phenanthroline-2-yl)phenyl}pyrimidine; synthesis of compound (1-137)> In Example 3, the same procedure was carried out by substituting 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}dibenzofuran with 4,4,5,5-tetramethyl-2-{4-(1,10-phenanthrolin-2-yl)phenyl}-1,3,2-dioxaborolan to obtain 7.5 g (yield: 46.8%) of the white powder 2-{4-(phenanthrene-9-yl)phenyl}-5-{4-(1,10-phenanthrolin-2-yl)phenyl}pyrimidine; compound (1-137).

[0085] [ka] (1-137)

[0086] The structure of the obtained white powder was identified using NMR. 1 The following 26 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.47(1H), 8.82(1H), 8.76(1H), 8.47(1H), 8.39(2H), 8.31(1H), 8.21(1H), 8.17(1H), 8.03(1 H), 8.00-7.89(6H), 7.86(1H), 7.78(1H), 7.74(2H), 7.70(2H), 7.66(1H), 7.61(1H), 7.56-7.50(2H).

[0087] [Example 6] <2,5-Bis{4-(dibenzothiophen-4-yl)phenyl}pyrimidine; Synthesis of compounds (1-20)> In Example 1, the same procedure was carried out by substituting 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborolane with 4,4,5,5-tetramethyl-2-{4-(dibenzothiophen-4-yl)phenyl}-1,3,2-dioxaborolane to obtain 4.0 g (yield: 40.0%) of a white powder of 2,5-bis{4-(dibenzothiophen-4-yl)phenyl}pyrimidine compound (1-20).

[0088] [ka] (1-20)

[0089] The structure of the obtained white powder was identified using NMR. 1 The following 24 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.18(2H), 8.69(2H), 8.23(4H), 7.95(4H), 7.86(4H), 7.64-7.54(4H), 7.54-7.45(4H).

[0090] [Example 7] <2,5-Bis{4-(1,10-phenanthroline-2-yl)phenyl}pyrimidine; Synthesis of compound (1-154)> In Example 1, the same procedure was carried out by substituting 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborolane with 4,4,5,5-tetramethyl-2-{4-(1,10-phenanthrolin-2-yl)phenyl}-1,3,2-dioxaborolane to obtain 10.6 g (yield: 59.5%) of 2,5-bis{4-(1,10-phenanthrolin-2-yl)phenyl}pyrimidine; compound (1-154) as a white powder.

[0091] [ka] (1-154)

[0092] The structure of the obtained white powder was identified using NMR. 1 The following 24 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.28(1H), 8.80(1H), 8.75(1H), 8.50(2H), 8.33(1H), 8.27(1H), 8.18(1H), 8.03(1H), 7.95-7.74(8H), 7.72-7.54(7H).

[0093] [Example 8] <5-(dibenzofuran-3-yl)-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-89)> 30.0 g of 2,5-dichloropyrimidine, 66.0 g of 2-9,9'-spirobio[9H]fluorenboronic acid, 2.1 g of tetrakis(triphenylphosphine)palladium(0), and 38.0 g of potassium carbonate were added to a nitrogen-purged reaction vessel and stirred under reflux overnight in a mixed solvent of toluene / ethanol / water. After cooling, toluene / water was added, and the organic layer was collected by extraction and liquid-liquid extraction and concentrated to obtain the crude product. The obtained crude product was purified by column chromatography (support: silica gel, eluent: dichloromethane / n-heptane) to obtain 39.0 g of 5-chloro-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine as a white powder (yield: 49.6%).

[0094] 9.5 g of the obtained 5-chloro-2-(9,9'-spirobi[9H]fluorene-2-yl)pyrimidine was added to a reaction vessel purged with nitrogen. Further, 5.2 g of (dibenzofuran-3-yl)boronic acid, 6.1 g of tripotassium phosphate, 0.2 g of tris(dibenzylideneacetone)dipalladium(0), 0.1 g of tricyclohexylphosphine, 100 mL of 1,4-dioxane, and 30 mL of purified water were added, and the mixture was stirred overnight under heating and reflux. After cooling, methanol was added, and the precipitated solid was collected by filtration to obtain a crude product. The obtained crude product was subjected to crystallization purification with a mixed solvent of chlorobenzene / acetone to obtain 8.4 g (yield: 68.0%) of a white powder of 5-(dibenzofuran-3-yl)-2-(9,9'-spirobi[9H]fluorene-2-yl)pyrimidine; Compound (1-89).

[0095] [Chemical formula] (1-89)

[0096] The structure of the obtained white powder was identified using NMR. 1 The following 24 hydrogen signals were detected by 1H-NMR (CDCl3). δ (ppm) = 8.97 (2H), 8.61 (1H), 8.04 (1H), 8.00 (1H), 7.98 (1H), 7.92 (1H), 7.90 (1H), 7.88 (2H), 7.74 (1H), 7.59 (1H), 7.53 (1H), 7.49 (1H), 7.39 (4H), 7.14 (1H), 7.11 (2H), 6.79 (2H), 6.74 (1H).

[0097] [Example 9] [Synthesis of 5-{4-(naphthalen-1-yl)phenyl}-2-(9,9'-spirobi[9H]fluorene-2-yl)pyrimidine; Compound (1-142)] In Example 8, the same procedure was carried out by substituting (dibenzofuran-3-yl)boronic acid with 4-(naphthalen-1-yl)phenylboronic acid to obtain 9.8 g (yield: 71.0%) of a white powder of 5-{4-(naphthalen-1-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-142).

[0098] [ka] (1-142)

[0099] The structure of the obtained white powder was identified using NMR. 1 The following 28 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.98(2H), 8.62(1H), 8.01(1H), 7.90(7H), 7.65(4H), 7.58-7.34(7H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0100] [Example 10] <5-{4-(naphthalene-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-143)> In Example 8, the same procedure was carried out by substituting (dibenzofuran-3-yl)boronic acid with 4-(naphthalene-2-yl)phenylboronic acid to obtain 10.6 g (yield: 76.3%) of 5-{4-(naphthalene-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-143) as a white powder.

[0101] [ka] (1-143)

[0102] The structure of the obtained white powder was identified using NMR. 1 The following 28 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.95(2H), 8.60(1H), 8.07(1H), 8.00(1H), 7.96-7.81(9H), 7.76(1H ), 7.67(2H), 7.51(2H), 7.38(3H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0103] [Example 11] <5-{4-(benzothiophen-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-146)> In Example 8, the same procedure was carried out by substituting (dibenzofuran-3-yl)boronic acid with 4,4,5,5-tetramethyl-2-{4-(benzothiophen-2-yl)phenyl}-1,3,2-dioxaborolane to obtain 9.4 g (yield: 70.0%) of a white powder of 5-{4-(benzothiophen-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-146).

[0104] [ka] (1-146)

[0105] The structure of the obtained white powder was identified using NMR. 1 The following 26 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.93(2H), 8.60(1H), 8.00(1H), 7.92(1H), 7.90-7.81(6H), 7.79( 1H), 7.62(3H), 7.43-7.30(5H), 7.14(1H), 7.11(2H), 6.78(2H), 6.74(1H).

[0106] [Example 12] <5-{4-(benzoxazole-2-yl)phenyl}-2-(9,9'-spirobi[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-147)> In Example 8, the same procedure was carried out by substituting (dibenzofuran-3-yl)boronic acid with 4,4,5,5-tetramethyl-2-{4-(benzoxazole-2-yl)phenyl}-1,3,2-dioxaborolane to obtain 12.5 g (yield: 91.2%) of 5-{4-(benzoxazole-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-147) as a white powder.

[0107] [ka] (1-147)

[0108] The structure of the obtained white powder was identified using NMR. 1 The following 25 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.96(2H), 8.61(1H), 8.37(2H), 8.00(1H), 7.92(1H), 7.90(1H), 7.88(2H), 7.8 0(1H), 7.72(2H), 7.61(1H), 7.42-7.35(5H), 7.15(1H), 7.11(2H), 6.78(2H), 6.74(1H).

[0109] [Example 13] <5-{4-(benzothiazole-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-148)> In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4,4,5,5-tetramethyl-2-{4-(benzothiazole-2-yl)phenyl}-1,3,2-dioxaborolane, and the same procedure was carried out to obtain 11.5 g (yield: 81.6%) of 5-{4-(benzothiazole-2-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-148) as a white powder.

[0110] [ka] (1-148)

[0111] The structure of the obtained white powder was identified using NMR. 1 The following 25 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.95(2H), 8.61(1H), 8.22(2H), 8.10(1H), 8.00(1H), 7.92(2H), 7.89(1H), 7.8 8(2H), 7.69(2H), 7.52(1H), 7.44-7.35(4H), 7.15(1H), 7.11(2H), 6.78(2H), 6.75(1H).

[0112] [Example 14] <5-{4-(9-phenylcarbazole-3-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; synthesis of compound (1-149)> In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4,4,5,5-tetramethyl-2-{4-(9-phenyl-carbazole-3-yl)phenyl}-1,3,2-dioxaborolane, and the same procedure was carried out to obtain 10.1 g (yield: 62.9%) of a pale yellow powder of 5-{4-(9-phenyl-carbazole-3-yl)phenyl}-2-(9,9'-spirobio[9H]fluoren-2-yl)pyrimidine; compound (1-149).

[0113] [ka] (1-149)

[0114] The structure of the obtained pale yellow powder was identified using NMR. 1 The following 33 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=8.97(2H), 8.61(1H), 8.38(1H), 8.20(1H), 8.00(1H), 7.92(1H), 7.90(1H), 7.88(2H), 7.85(2H), 7.7 0-7.56(7H), 7.50(1H), 7.48(1H), 7.43(2H), 7.38(3H), 7.32(1H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0115] [Example 15] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthalene-2-yl)phenyl}pyrimidine; synthesis of compound (1-150)> In Example 3, the same procedure was carried out by substituting 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}dibenzofuran with 4,4,5,5-tetramethyl-2-{3,5-bis(naphthalene-2-yl)phenyl}-1,3,2-dioxaborolan to obtain 1.8 g (yield: 22.2%) of the white powder 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthalene-2-yl)phenyl}pyrimidine; compound (1-150).

[0116] [ka] (1-150)

[0117] The structure of the obtained white powder was identified using NMR. 1 The following 32 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.25(2H), 8.81(1H), 8.75(1H), 8.69(2H), 8.22(2H), 8.16(1H), 8. 04-7.88(12H), 7.77(1H), 7.74(2H), 7.70(2H), 7.64(1H), 7.60-7.51(5H).

[0118] [Example 16] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyrimidine; synthesis of compound (1-151)> In Example 3, the same procedure was carried out by substituting 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl}dibenzofuran with 4,4,5,5-tetramethyl-2-{3,5-bis(quinoline-3-yl)phenyl}-1,3,2-dioxaborolan to obtain 4.3 g (yield: 47.6%) of the white powder 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyrimidine; compound (1-151).

[0119] [ka] (1-151)

[0120] The structure of the obtained white powder was identified using NMR. 1 The following 30 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.34(2H), 9.24(2H), 8.80(1H), 8.74(1H), 8.69(2H), 8.49(2H), 8.22(2H), 8.13(1H), 8.0 3(2H), 8.00(1H), 7.97(2H), 7.93(1H), 7.80(2H), 7.77(1H), 7.74(2H), 7.72-7.61(5H), 7.57(1H).

[0121] [Example 17] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthalene-2-yl)phenyl}pyridine; synthesis of compound (1-152)> In a nitrogen-purged reaction vessel, 9.3 g of 2,5-dichloropyridine, 10.0 g of 4,4,5,5-tetramethyl-2-{4-(phenanthren-9-yl)phenyl}-1,3,2-dioxaborolane, 0.8 g of tetrakis(triphenylphosphine)palladium(0), and 10.9 g of potassium carbonate were added, and the mixture was stirred under reflux in a toluene / ethanol / water mixed solvent for 5 hours. After cooling, toluene / water was added, and the organic layer was collected by extraction and liquid-liquid extraction and concentrated to obtain the crude product. The obtained crude product was purified by column chromatography (support: silica gel, eluent: toluene / n-heptane) to obtain 9.6 g of 5-chloro-2-{4-(phenanthren-9-yl)phenyl}pyridine as a white powder (yield: 81.5%).

[0122] 5.0 g of the obtained 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyridine was added to a nitrogen-purged reaction vessel. Further additions included 6.7 g of 4,4,5,5-tetramethyl-2-{3,5-bis(naphthalene-2-yl)phenyl}-1,3,2-dioxaborolane, 0.4 g of tetrakis(triphenylphosphine)palladium(0), and 2.5 g of potassium carbonate. The mixture was stirred under reflux overnight in a toluene / ethanol / water mixed solvent. After cooling, methanol was added, and the precipitated solid was collected by filtration to obtain the crude product. The crude product was recrystallized and purified in toluene to obtain 6.7 g of a white powder (yield: 83.3%) of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthalene-2-yl)phenyl}pyridine; compound (1-152).

[0123] [ka] (1-152)

[0124] The structure of the obtained white powder was identified using NMR. 1 The following 33 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.17(1H), 8.80(1H), 8.75(1H), 8.25(2H), 8.22(2H), 8.18(1H), 8.12(1H), 8. 04-7.95(8H), 7.95-7.88(5H), 7.76(1H), 7.74-7.66(4H), 7.64(1H), 7.60-7.51(5H).

[0125] [Example 18] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyridine; synthesis of compound (1-153)> In Example 17, the same procedure was carried out by substituting 4,4,5,5-tetramethyl-2-{3,5-bis(naphthalene-2-yl)phenyl}-1,3,2-dioxaborolane with 4,4,5,5-tetramethyl-2-{3,5-bis(quinoline-3-yl)phenyl}-1,3,2-dioxaborolane to obtain 5.3 g (yield: 73.0%) of the white powder 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyridine; compound (1-153).

[0126] [ka] (1-153)

[0127] The structure of the obtained white powder was identified using NMR. 1 The following 31 hydrogen signals were detected by 1H-NMR (CDCl3). δ(ppm)=9.34(2H), 9.16(2H), 8.80(1H), 8.74(1H), 8.48(2H), 8.28(2H), 8.21(2H), 8.17(1H) , 8.08(1H), 8.05(2H), 8.00(2H), 7.96(2H), 7.92(1H), 7.79(2H), 7.74-7.60(7H), 7.56(1H).

[0128] [Example 19] The glass transition temperature (Tg) and melting point of the heterocyclic compound represented by general formula (1) were measured using a high-sensitivity differential scanning calorimeter (Bruker AXS, DSC3100SA). The measurement results are summarized in Table 1.

[0129] [Table 1]

[0130] Thus, the heterocyclic compound represented by general formula (1) of the present invention has a glass transition temperature (Tg) of 100°C or higher, or does not exhibit a glass transition temperature (Tg), indicating that the thin film state is stable.

[0131] [Example 20] A heterocyclic compound represented by general formula (1) was used to fabricate a vapor-deposited film with a thickness of 80 nm on a silicon substrate. The refractive index n at wavelengths of 450 nm and 750 nm was measured using a spectroscopic analyzer (F10-RT-UV, Filmetrics). For comparison, the refractive index n of the comparative compound (2-1) with the following structural formula and Alq3 were also measured. The measurement results are summarized in Table 2.

[0132] [ka] (2-1)

[0133] [Table 2]

[0134] Thus, the refractive index n of the heterocyclic compound represented by the general formula (1) of the present invention has a value equal to or greater than that of Alq3 and comparative compound (2-1) in the wavelength range of 450 nm to 750 nm. This indicates that by using the heterocyclic compound represented by the general formula (1) of the present invention as a constituent material for the capping layer, an improvement in the light extraction efficiency of organic EL elements can be expected.

[0135] [Example 21] As shown in Figure 12, the organic EL element was fabricated by pre-forming a reflective ITO electrode as a metal anode 2 on a glass substrate 1, and then depositing the following layers in order: hole injection layer 3, hole transport layer 4, light-emitting layer 5, electron transport layer 6, electron injection layer 7, cathode 8, and capping layer 9.

[0136] Specifically, a metal anode 2 was formed on a glass substrate 1 by sequentially depositing ITO with a thickness of 50 nm, a reflective silver alloy with a thickness of 100 nm, and ITO with a thickness of 5 nm. This was then ultrasonically cleaned in isopropyl alcohol for 20 minutes, and dried on a hot plate heated to 250°C for 10 minutes. After that, UV ozone treatment was performed for 2 minutes, and then this ITO-coated glass substrate was placed in a vacuum deposition machine and the pressure was reduced to 0.001 Pa or less. Subsequently, a hole injection layer 3 was formed covering the metal anode 2 by binary deposition of an electron acceptor (Acceptor-1) with the following structural formula and a compound (3-1) with the following structural formula, at a deposition rate ratio of (Acceptor-1):compound (3-1)=3:97, to a thickness of 10 nm. On this hole injection layer 3, a hole transport layer 4 was formed using the compound (3-1) with the following structural formula to a thickness of 140 nm. On this hole transport layer 4, two compounds with the following structural formulas (3-2) and (3-3) were deposited as an emissive layer 5 using a binary deposition method with a deposition rate ratio of compound (3-2):compound (3-3)=5:95, resulting in a film thickness of 20 nm. On this emissive layer 5, two compounds with the following structural formulas (3-4) and (3-5) were deposited as an electron transport layer 6 using a binary deposition method with a deposition rate ratio of compound (3-4):compound (3-5)=50:50, resulting in a film thickness of 30 nm. On this electron transport layer 6, lithium fluoride was deposited as an electron injection layer 7 to a film thickness of 1 nm. On this electron injection layer 7, a magnesium-silver alloy was deposited as a cathode 8 to a film thickness of 12 nm. Finally, compound (1-7) from Example 1 was deposited as a capping layer 9 to a film thickness of 60 nm. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0137] [ka] (Acceptor-1)

[0138] [ka] (3-1)

[0139] [ka] (3-2)

[0140] [ka] (3-3)

[0141] [ka] (3-4)

[0142] [ka] (3-5)

[0143] [ka] (1-7)

[0144] [Example 22] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-41) from Example 2 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0145] [ka] (1-41)

[0146] [Example 23] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-71) from Example 3 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0147] [ka] (1-71)

[0148] [Example 24] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-74) from Example 4 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0149] [ka] (1-74)

[0150] [Example 25] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-137) from Example 5 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0151] [ka] (1-137)

[0152] [Example 26] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-20) from Example 6 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0153] [ka] (1-20)

[0154] [Example 27] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-154) from Example 7 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0155] [ka] (1-154)

[0156] [Example 28] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-89) from Example 8 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0157] [ka] (1-89)

[0158] [Example 29] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-142) from Example 9 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0159] [ka] (1-142)

[0160] [Example 30] In Example 21, an organic EL element was fabricated under the same conditions as in Example 10, except that the compound (1-143) from Example 1 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0161] [ka] (1-143)

[0162] [Example 31] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-146) from Example 1 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0163] [ka] (1-146)

[0164] [Example 32] In Example 21, an organic EL device was fabricated under the same conditions except that compound (1-147) of Example 12 was used instead of compound (1-7) of Example 1 as the capping layer 9. For the fabricated organic EL device, characteristic measurements were performed at room temperature in air. The measurement results of the emission characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0165] [Chemical Formula] (1-147)

[0166] [Example 33] In Example 21, an organic EL device was fabricated under the same conditions except that compound (1-148) of Example 13 was used instead of compound (1-7) of Example 1 as the capping layer 9. For the fabricated organic EL device, characteristic measurements were performed at room temperature in air. The measurement results of the emission characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0167] [Chemical Formula] (1-148)

[0168] [Example 34] In Example 21, an organic EL device was fabricated under the same conditions except that compound (1-149) of Example 14 was used instead of compound (1-7) of Example 1 as the capping layer 9. For the fabricated organic EL device, characteristic measurements were performed at room temperature in air. The measurement results of the emission characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0169] [Chemical Formula] (1-149)

[0170] [Example 35] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-150) from Example 1 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0171] [ka] (1-150)

[0172] [Example 36] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-151) from Example 16 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0173] [ka] (1-151)

[0174] [Example 37] In Example 21, an organic EL element was fabricated under the same conditions as in Example 1, except that the compound (1-152) from Example 17 was used as the capping layer 9 instead of the compound (1-7) from Example 1. The fabricated organic EL element was subjected to characteristic measurements in air at room temperature. Table 3 summarizes the measurement results of the light emission characteristics when a DC voltage was applied to the fabricated organic EL element.

[0175] [ka] (1 - 152)

[0176] [Example 38] In Example 21, an organic EL device was fabricated under the same conditions except that the compound (1 - 153) of Example 18 was used instead of the compound (1 - 7) of Example 1 as the capping layer 9. The characteristics of the fabricated organic EL device were measured at room temperature in the air. The measurement results of the light - emitting characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0177] [Chemical Formula] (1 - 153)

[0178] [Comparative Example 1] For comparison, in Example 21, an organic EL device was fabricated under the same conditions except that Alq3 was used instead of the compound (1 - 7) of Example 1 as the capping layer 9. The characteristics of the fabricated organic EL device were measured at room temperature in the air. The measurement results of the light - emitting characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0179] [Comparative Example 2] For comparison, in Example 21, an organic EL device was fabricated under the same conditions except that the comparative compound (2 - 1) was used instead of the compound (1 - 7) of Example 1 as the capping layer 9. The characteristics of the fabricated organic EL device were measured at room temperature in the air. The measurement results of the light - emitting characteristics obtained by applying a DC voltage to the fabricated organic EL device are summarized in Table 3.

[0180] Using the organic EL devices fabricated in Examples 21 - 38 and Comparative Examples 1 - 2, the results of measuring the device lifetime are summarized in Table 3. The device lifetime was measured as the time (95% decay) until the luminance decayed to 95% of the initial luminance when a constant - current drive of 10 mA / cm 2 was performed.

[0181] [Table 3]

[0182] As shown in Table 3, the current density is 10 mA / cm². 2 The driving voltage at time was almost the same for the elements of Comparative Examples 1 and 2 and for the elements of Examples 21 to 38, which used the heterocyclic compound represented by the general formula (1) of the present invention as the capping layer. However, in terms of brightness, luminous efficiency, power efficiency, and element lifetime, the elements of Examples 21 to 38 showed significant improvements compared to the elements of Comparative Examples 1 and 2. This indicates that the heterocyclic compound represented by the general formula (1) of the present invention is a suitable material for use in the capping layer, and that the high refractive index of the capping layer can significantly improve the light extraction efficiency of the organic EL element. [Industrial applicability]

[0183] The heterocyclic compound represented by general formula (1) of the present invention has a high refractive index, significantly improves light extraction efficiency, and maintains a stable thin film state, making it an excellent compound for use in the capping layer of organic EL elements. Organic EL elements fabricated using the heterocyclic compound represented by general formula (1) of the present invention can achieve high efficiency. Furthermore, by using the heterocyclic compound represented by general formula (1) of the present invention, which does not absorb in the blue, green, and red wavelength regions, it is particularly suitable for displaying images with good color purity, clarity, and brightness. For example, it has become possible to develop applications in home appliances and lighting. [Explanation of Symbols]

[0184] 1. Glass substrate 2 metal anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6 Electron transport layer 7 Electron injection layer 8 cathode 9. Capping layer

Claims

1. A heterocyclic compound represented by the following general formula (1). 【Chemistry 1】 （１） (In the formula, X １ , X ２ These may be identical or different from each other, and represent a nitrogen atom or a CH group, with at least one being a nitrogen atom. １ , L ２ Ar may be identical or different from each other, and represents a divalent group formed by removing two hydrogen atoms from the 1,4-positions of a single bond or unsubstituted benzene ring. １ Ar ２ Ar1 and Ar2 may be identical or different from each other and represent substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted aromatic heterocyclic groups. However, if L1 and L2 are simultaneously single bonds, at least one of Ar1 and Ar2 is a substituted or unsubstituted spirobifluorenyl group. Also, if at least one of L1 and L2 is a divalent group formed by removing two hydrogen atoms from the 1,4-positions of an unsubstituted benzene ring, at least one of Ar1 and Ar2 is a substituted phenyl group, or Ar1 is a substituted or unsubstituted spirobifluorenyl group and Ar2 is a substituted carbazolyl group. Furthermore, when Ar1 and Ar2 have substituents, the substituents include cyano groups, nitro groups, halogen atoms, substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C1-C6 alkyloxy groups, substituted or unsubstituted phenyl groups, substituted or unsubstituted biphenyl groups, substituted or unsubstituted terphenyl groups, substituted or unsubstituted naphthyl groups, substituted or unsubstituted anthracenyl groups, substituted or unsubstituted phenantrenyl groups, substituted or unsubstituted fluorenyl groups, substituted or unsubstituted spirobifluorenyl groups, substituted or unsubstituted indenyl groups, substituted or unsubstituted pyrenyl groups, substituted or unsubstituted perilennyl groups, substituted or unsubstituted fluoranthenyl groups, substituted or unsubstituted triphenylenyl groups, substituted or unsubstituted pyridyl groups, substituted or unsubstituted pyrimidinyl groups, substituted or unsubstituted triazinyl groups, and substituted groups. Alternatively, it may be selected from an unsubstituted furyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted quinolyl group, a substituted or unsubstituted isoquinolyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted naphthilidinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted carboninyl group, a substituted or unsubstituted benzoxazolyl group, a substituted or unsubstituted benzothiazolyl group, and a substituted or unsubstituted phenoxadinyl group.

2. The heterocyclic compound according to claim 1, wherein the heterocyclic compound is represented by the following general formula (1-a). 【Chemistry 2】 (1-a) (wherein X １ , X ２ may be the same as or different from each other and represents a nitrogen atom or a CH group, and at least one of them is a nitrogen atom. L １ , L ２ may be the same as or different from each other and represents a single bond or a divalent group formed by removing two hydrogen atoms at the 1,4-positions of unsubstituted benzene. Ar １ , Ar ２ may be the same as or different from each other and represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group. However, when L1 and L2 are simultaneously single bonds, at least one of Ar1 and Ar2 is a substituted or unsubstituted spirobifluorenyl group. Also, when at least one of L1 and L2 is a divalent group formed by removing two hydrogen atoms at the 1,4-positions of unsubstituted benzene, at least one of Ar1 and Ar2 is a phenyl group having a substituent, or Ar1 is a substituted or unsubstituted spirobifluorenyl group and Ar2 is a carbazolyl group having a substituent. Furthermore, when Ar1 and Ar2 have substituents, the substituents include cyano groups, nitro groups, halogen atoms, substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C1-C6 alkyloxy groups, substituted or unsubstituted phenyl groups, substituted or unsubstituted biphenyl groups, substituted or unsubstituted terphenyl groups, substituted or unsubstituted naphthyl groups, substituted or unsubstituted anthracenyl groups, substituted or unsubstituted phenantrenyl groups, substituted or unsubstituted fluorenyl groups, substituted or unsubstituted spirobifluorenyl groups, substituted or unsubstituted indenyl groups, substituted or unsubstituted pyrenyl groups, substituted or unsubstituted perilennyl groups, substituted or unsubstituted fluoranthenyl groups, substituted or unsubstituted triphenylenyl groups, substituted or unsubstituted pyridyl groups, substituted or unsubstituted pyrimidinyl groups, substituted or unsubstituted triazinyl groups, and substituted groups. Alternatively, it may be selected from an unsubstituted furyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted quinolyl group, a substituted or unsubstituted isoquinolyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted naphthilidinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted carboninyl group, a substituted or unsubstituted benzoxazolyl group, a substituted or unsubstituted benzothiazolyl group, and a substituted or unsubstituted phenoxadinyl group.

3. The heterocyclic compound according to claim 1, wherein the heterocyclic compound is represented by the following general formula (1-b). 【Transformation 3】 (1-b) (In the formula, X １ , X ２ These may be identical or different from each other, and represent a nitrogen atom or a CH group, with at least one being a nitrogen atom. １ , L ２ Ar may be identical or different from each other, and represents a divalent group formed by removing two hydrogen atoms from the 1,4-positions of a single bond or unsubstituted benzene ring. １ Ar ２ Ar1 and Ar2 may be identical or different from each other and represent substituted or unsubstituted aromatic hydrocarbon groups or substituted or unsubstituted aromatic heterocyclic groups. However, if L1 and L2 are simultaneously single bonds, at least one of Ar1 and Ar2 is a substituted or unsubstituted spirobifluorenyl group. Also, if at least one of L1 and L2 is a divalent group formed by removing two hydrogen atoms from the 1,4-positions of an unsubstituted benzene ring, at least one of Ar1 and Ar2 is a substituted phenyl group, or Ar1 is a substituted or unsubstituted spirobifluorenyl group and Ar2 is a substituted carbazolyl group. Furthermore, when Ar1 and Ar2 have substituents, the substituents include cyano groups, nitro groups, halogen atoms, substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C1-C6 alkyloxy groups, substituted or unsubstituted phenyl groups, substituted or unsubstituted biphenyl groups, substituted or unsubstituted terphenyl groups, substituted or unsubstituted naphthyl groups, substituted or unsubstituted anthracenyl groups, substituted or unsubstituted phenantrenyl groups, substituted or unsubstituted fluorenyl groups, substituted or unsubstituted spirobifluorenyl groups, substituted or unsubstituted indenyl groups, substituted or unsubstituted pyrenyl groups, substituted or unsubstituted perilennyl groups, substituted or unsubstituted fluoranthenyl groups, substituted or unsubstituted triphenylenyl groups, substituted or unsubstituted pyridyl groups, substituted or unsubstituted pyrimidinyl groups, substituted or unsubstituted triazinyl groups, and substituted groups. Alternatively, it may be selected from an unsubstituted furyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted quinolyl group, a substituted or unsubstituted isoquinolyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted naphthilidinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted carboninyl group, a substituted or unsubstituted benzoxazolyl group, a substituted or unsubstituted benzothiazolyl group, and a substituted or unsubstituted phenoxadinyl group.

4. The heterocyclic compound according to Claim 1, characterized in that the heterocyclic compound is one of the following compounds (1-89), (1-149), (1-150), (1-151), (1-152), or (1-153). 【Chemistry 4】 （１－８９） 【Transformation 5】 （１－１４９） 【Transformation 6】 （１－１５０） 【Transformation 7】 （１－１５１） 【Transformation 8】 （１－１５２） 【Chemistry 9】 （１－１５３）

5. An organic thin film comprising a heterocyclic compound according to any one of claims 1 to 4, characterized in that the refractive index in the wavelength range of 450 nm to 750 nm is 1.70 or higher.

6. An organic electroluminescent 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 this order, wherein the capping layer is an organic thin film as described in claim 5.

7. An electronic device or electronic element having a pair of electrodes and at least one organic layer sandwiched between them, characterized in that the organic layer uses a heterocyclic compound according to any one of claims 1 to 4 as a constituent material.

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