TWI661030B - Organic electroluminescent device and method of manufacture thereof - Google Patents

Abstract

The present invention provides an organic electroluminescence element. In order to improve the element characteristics of the organic electroluminescence element, in particular to greatly improve the light extraction efficiency, the organic electroluminescence element is provided with a high refractive index, excellent film stability or durability, and a blue, The green and red wavelength regions do not have a covering layer composed of an absorbing material.

An organic electroluminescence element having at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a cover layer in order, the cover layer containing an aromatic amine compound represented by the following general formula (1);

Description

Organic electroluminescence element and manufacturing method thereof

The present invention relates to organic electroluminescence elements (hereinafter referred to as organic EL elements) which are self-luminous elements suitable for various display devices. More specifically, the present invention relates to organic EL elements using a specific aromatic amine compound, and particularly to light An organic EL element with significantly improved extraction efficiency.

The organic EL element is a self-luminous element, so it is brighter and has better visibility than a liquid crystal element, and can be a bright display, which has been actively researched.

In 1987, CWTang et al. Of Eastman Kodak Company developed a laminated structure element obtained by distributing various functions to various materials, making organic EL elements using organic materials practical. The organic EL elements will be able to transport electrons. The layered phosphor and the organic substance capable of transporting holes are laminated. The charge of the two is injected into the phosphor layer to emit light, and a high brightness of 1000 cd / m ² or higher is obtained at a voltage of 10 V or less (for example, refer to Patent Literature 1 and Patent Literature 2).

Until now, there have been many improvements for the practical use of organic EL elements, and various functions have been further subdivided. The substrate is sequentially provided with an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electrode. Among the electric field light-emitting elements of the sub-injection layer and the cathode, high efficiency and durability can be achieved by a light-emitting element having a bottom-emission structure that emits light from the bottom (see, for example, Non-Patent Document 1).

In recent years, a light-emitting element having a top light-emitting structure that uses a metal with a high work function as an anode and emits light from above has been used. Unlike the light-emitting element of the bottom light-emitting structure whose area of the light-emitting portion is limited by the pixel circuit, the light-emitting element of the top light-emitting structure has the advantage of a wide light-emitting portion. In a light-emitting element having a top emission structure, a cathode is made of a translucent electrode such as LiF / Al / Ag (see, for example, Non-Patent Document 2), Ca / Mg (see, for example, Non-Patent Document 3), or LiF / MgAg.

In such a light-emitting element, when the light emitted from the light-emitting layer is incident on another film, if it is incident at a certain angle or more, it will be totally reflected at the interface between the light-emitting layer and the other film. Therefore, only a part of the emitted light can be used. In recent years, in order to improve light extraction efficiency, a proposal has been made to provide a light-emitting element having a high refractive index "coating layer" outside a translucent electrode having a low refractive index (for example, see Non-Patent Documents 2 and 3).

In a light-emitting element with a top-emitting structure, the effect of the cover layer is as follows. In a light-emitting element using Ir (ppy) ₃ as a light-emitting material, the current efficiency is 38 cd / A without the cover layer, but 60 nm-thick ZnSe is used as the cover layer The obtained light-emitting element was 64 cd / A, and it was considered that the efficiency was improved by about 1.7 times. In addition, the maximum point of the transmittance and the maximum point of the efficiency of the translucent electrode and the cover layer do not necessarily match, and the maximum point display of the light extraction efficiency is determined by the interference effect (for example, refer to Non-Patent Document 3).

It has been proposed to use a high-definition metal mask when the cover layer is formed, but the metal mask has a problem that the accuracy of positional alignment deteriorates due to deformation caused by heat. That is, the melting point of ZnSe is as high as 1100 ° C or higher (for example, refer to Non-Patent Document 3). When a high-definition mask is used, steam cannot be vaporized at the correct position. plating. Many inorganic substances have a high vapor deposition temperature, which is not suitable for using a high-definition mask, and may cause damage to the light-emitting element itself. In addition, when a film is formed by a sputtering method, a light-emitting element is damaged, so an inorganic substance cannot be used as a cover layer of a constituent material.

As a coating for adjusting the refractive index, it is known that when using (8-hydroxyquinoline) aluminum (hereinafter referred to as Alq ₃ ) (for example, refer to Non-Patent Document 2), Alq ₃ is used as a green light emitting material or an electron transport material. Generally used organic EL materials, but with weak absorption near 450 nm used in blue light-emitting elements. Therefore, in the case of a blue light emitting element, there is a problem that the color purity is lowered and the light extraction efficiency is lowered.

In order to improve the element characteristics of the organic EL element, and in particular to greatly improve the light extraction efficiency, as a material of the cover layer, a material having a high refractive index and excellent film stability or durability is sought.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 8-048656

[Patent Document 2] Japanese Patent No. 3194657

[Patent Document 3] WO2013-038627

[Non-patent literature]

[Non-Patent Document 1] Proceedings of the 9th Workshop of the Applied Physics Society, pp. 55 ~ 61 (2001)

[Non-Patent Document 2] Appl. Phys. Lett., 78,544 (2001)

[Non-Patent Document 3] Appl. Phys. Lett., 82, 466 (2003)

[Non-Patent Document 4] Aust. J. Chem., 45, 371 (1992)

[Non-Patent Document 5] J. Org. Chem., 60, 7508 (1995)

[Non-Patent Document 6] Synth. Commun., 11,513 (1981)

[Non-Patent Document 7] Appl. Phys. Let., 98, 083302 (2011)

An object of the present invention is to provide an organic EL element, which has high refractive index, excellent film stability, and durability in order to improve the element characteristics of the organic EL element, in particular, to greatly improve the light extraction efficiency, and is excellent in blue. Cover layers made of non-absorptive materials in the respective wavelength regions of, green and red.

As physical properties in the material suitable for the cover layer of the present invention, (1) high refractive index, (2) vapor deposition without thermal decomposition, (3) stable film state, and (4) high glass transition temperature. In addition, as the physical characteristics of a device suitable for the present invention, (1) high extraction efficiency of light, (2) color purity does not decrease, (3) light transmission without changing with time, and (4) long life .

In order to achieve the above-mentioned object, the inventors of the present case focused on the excellent film stability and durability of the arylamine-based material, selected a specific arylamine compound with a high refractive index as a material constituting the coating layer, and made an organic EL device. Characteristic evaluation, the result reached the invention.

That is, according to the present invention, the following organic EL elements are provided.

1) An organic electroluminescence element having at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a cover layer in this order, the cover layer containing an aromatic amine compound represented by the following general formula (1);

(Wherein Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ may be the same as or different from each other, and represent a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or Unsubstituted condensed polycyclic aromatic group, n represents an integer of 0 to 4; Here, at least one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is a monovalent group represented by the following structural formula (B) Or has the monovalent group as a substituent)

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ may be the same as or different from each other, and are a linking group, a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a substituent group. A straight or branched alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms having a substituent, or a straight chain having 2 to 6 carbon atoms having a substituent Or branched alkenyl, linear or branched alkoxy having 1 to 6 carbon atoms having a substituent, cycloalkoxy having 5 to 10 carbon atoms having a substituent, substituted or Unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group and can also be mediated A single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ is bonded to each other to form a ring; X represents a carbon atom or a nitrogen atom, and Y represents a carbon atom, an oxygen atom, or a sulfur atom Or nitrogen atom, Ar ₅ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted Or an unsubstituted condensed polycyclic aromatic group or a linking group, Ar ₆ and Ar ₇ may be the same as or different from each other, and are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic hetero A cyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group, or a linking group, when Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ to 0, and X and Y are nitrogen atoms, then Ar _{When any of 5} , Ar ₆ and Ar ₇ is a substituent or a linking group, and X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ 0. Ar ₈ represents a substituted or unsubstituted group. Aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group. R ₁ , R ₂ , R ₃ , R ₄ , Ar ₅ , Ar ₆ Only one of Ar ₇ is a linking group, and the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom is excluded. In addition, Ar ₆ , Ar ₆ , and Ar ₇ may be the same or different.)

2) The organic EL device according to the above 1), wherein the aforementioned structural formula (B) is a monovalent group represented by the following structural formula (B-1);

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ may be the same as or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a number of carbon atoms which may have a substituent. A linear or branched alkyl group having 1 to 6 or a cycloalkyl group having 5 to 10 carbon atoms having a substituent or a linear or branching olefin having 2 to 6 carbon atoms having a substituent It may be a linear or branched alkoxy group having 1 to 6 carbon atoms having a substituent, a cycloalkoxy group having 5 to 10 carbon atoms having a substituent, a substituted or unsubstituted Aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, substituted or unsubstituted condensed polycyclic aromatic groups, or substituted or unsubstituted aryloxy groups and may also be separated by a single bond, A substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ is bonded to each other to form a ring. Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic group Heterocyclyl, or substituted or unsubstituted condensed polycyclic aromatic group.)

3) The organic EL device according to the above 1), wherein the aforementioned structural formula (B) is a monovalent group represented by the following structural formula (B-2);

(Wherein R ₁ , R ₃ , and R ₄ may be the same as or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a substituent having 1 to 6 carbon atoms It may be a linear or branched alkyl group, a cycloalkyl group having 5 to 10 carbon atoms having a substituent, or a linear or branched alkenyl group having 2 to 6 carbon atoms having a substituent. It may have a linear or branched alkoxy group having 1 to 6 carbon atoms with a substituent, a cycloalkoxy group having 5 to 10 carbon atoms with a substituent, a substituted or unsubstituted aromatic hydrocarbon group , Substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, R ₃ and R ₄ can also be separated by a single Bond, substituted or unsubstituted methylene, oxygen atom, sulfur atom, or N-Ar ₈ to form a ring with each other. Ar ₆ and Ar ₈ may be the same or different from each other, and represent a substituted or unsubstituted aromatic Hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group.)

4) The organic EL device according to the above 1), wherein the aforementioned structural formula (B) is a monovalent group represented by the following structural formula (B-3);

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ may be the same as or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a number of carbon atoms which may have a substituent. A linear or branched alkyl group having 1 to 6 may be a cycloalkyl group having 5 to 10 carbon atoms having a substituent, or a linear or branching olefin having 2 to 6 carbon atoms having a substituent. It may be a linear or branched alkoxy group having 1 to 6 carbon atoms having a substituent, a cycloalkoxy group having 5 to 10 carbon atoms having a substituent, a substituted or unsubstituted Aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, substituted or unsubstituted condensed polycyclic aromatic groups, or substituted or unsubstituted aryloxy groups, and may also be separated by a single bond , Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ and bonded to each other to form a ring. Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group.)

5) The organic EL element according to the above 1), wherein the aforementioned structural formula (B) is a monovalent group represented by the following structural formula (B-4);

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ may be the same as or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a number of carbon atoms which may have a substituent. A linear or branched alkyl group having 1 to 6 may be a cycloalkyl group having 5 to 10 carbon atoms having a substituent, or a linear or branching olefin having 2 to 6 carbon atoms having a substituent. It may be a linear or branched alkoxy group having 1 to 6 carbon atoms having a substituent, a cycloalkoxy group having 5 to 10 carbon atoms having a substituent, a substituted or unsubstituted Aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, substituted or unsubstituted condensed polycyclic aromatic groups, or substituted or unsubstituted aryloxy groups, and may also be separated by a single bond , Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ and bonded to each other to form a ring. Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group.)

6) The organic EL device according to the above 1), wherein the aforementioned structural formula (B) is a monovalent group represented by the following structural formula (B '); [Chem. 7]

(In the formula, R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ may be the same as or different from each other, and are a linking group, or a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, or a nitro group. A linear or branched alkyl group having 1 to 6 carbon atoms may be substituted, a cycloalkyl group having 5 to 10 carbon atoms may be substituted, or a carbon atom 2 may be substituted Linear or branched alkenyl groups of 6 to 6, linear or branched alkoxy groups having 1 to 6 carbon atoms may be substituted, and cycloalkanes having 5 to 10 carbon atoms may be substituted Oxygen, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aromatic group Oxygen, and may be bonded to each other via a single bond, substituted or unsubstituted methylene, oxygen atom, sulfur atom, or N-Ar ₈ to form a ring. X represents a carbon atom or a nitrogen atom, and Y is a carbon atom , an oxygen atom, a sulfur atom, or a nitrogen atom, Ar ₅ represents a substituted or non-substituted aromatic hydrocarbon group, substituted or non-substituted aromatic heterocyclic group, The substituted or unsubstituted condensed polycyclic aromatic group, or a linking group, and Ar _6, Ar ₇ may be the same or different and each represents a substituted or non-substituted aromatic hydrocarbon group, substituted or non-substituted When an aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group, or a linking group, and Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ 0, and X and Y are nitrogen atoms In this case, when any of Ar ₅ , Ar ₆ , and Ar ₇ is a substituent or a linking group, and X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ 0. Ar ₈ represents a substituted or Unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group. R ₃ , R ₄ , R ₅ , R ₆ , R ₍₇ , R ₈ , Ar ₅ , Ar ₆ , and Ar ₇ are only linking groups, and the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom is excluded.)

7) The organic EL element according to the above 1), wherein n is 0 in the general formula (1).

8) The organic EL device according to 1) above, wherein n is 1 in the general formula (1).

9) The organic EL element according to the above 1), wherein n is 2 in the general formula (1).

10) The organic EL device according to the above 1), wherein in the general formula (1), any one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is a monovalent group represented by the structural formula (B), Or it has this monovalent group as a substituent.

11) The organic EL device according to the above 1), wherein in the general formula (1), Ar ₁ and Ar ₄ are a monovalent group represented by the structural formula (B), or have the monovalent group as a substituent.

12) The organic EL device according to the above 1), wherein the thickness of the cover layer is in a range of 30 nm to 120 nm.

13) The organic EL device according to the above 1), wherein the refractive index of the cover layer is 1.85 or more within a range of a wavelength of light transmitted through the cover layer of 450 nm to 750 nm.

14) A method of using the compound represented by the general formula (1) as in 1) as a cover layer of an organic electroluminescence device.

As the "substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted aromatic heterocyclic group" or "substituted or unsubstituted" represented by Ar ₁ to Ar ₄ in the general formula (1) Specific examples of the "aromatic hydrocarbon group", "aromatic heterocyclic group" or "condensed polycyclic aromatic group" in the "condensed polycyclic aromatic group" include phenyl, biphenyl, bitriphenyl, Naphthyl, anthryl, phenanthryl, fluorenyl, indenyl, fluorenyl, fluorenyl, fluorobuthenyl (fluoranthenyl), ditriphenylene, pyridyl, furyl, pyrrolyl, thienyl, Quinolinyl, isoquinolinyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, benzotriazolyl, benzo An oxazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbolinyl group, and the like. Ar ₁ and Ar ₂ or Ar ₃ and Ar ₄ may be bonded to each other to form a ring through a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ . Here, "N" of "N-Ar ₈ " represents a nitrogen atom, "Ar ₈ " represents "a substituted or unsubstituted aromatic hydrocarbon group", "a substituted or unsubstituted aromatic heterocyclic group", or The "substituted or unsubstituted condensed polycyclic aromatic group" includes the same groups as those exemplified above, and the substituents which these groups may also have the same substituents as those exemplified below.

As a "substituent" in the "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group" or "substituted condensed polycyclic aromatic group" represented by Ar ₁ to Ar ₄ in the general formula (1), specifically, Examples include deuterium, trifluoromethyl, cyano, and nitro; halogen atoms such as fluorine, chlorine, bromine, and iodine; methyl, ethyl, n-propyl, isopropyl, n-butyl, and iso Linear or branched alkyl groups having 1 to 6 carbon atoms, such as butyl, third butyl, n-pentyl, isopentyl, neopentyl, and n-hexyl; methoxy, ethoxy, and propoxy Linear or branched alkoxy groups with 1 to 6 carbon atoms; alkenyl groups such as allyl groups; aralkyl groups such as benzyl, naphthylmethyl, and phenethyl groups; aromatic groups such as phenoxy and tolyloxy groups Oxy; aryl alkoxy such as benzyloxy, phenethyloxy; phenyl, biphenyl, bitriphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, indenyl, fluorenyl, fluorenyl Aromatic hydrocarbon groups or condensed polycyclic aromatic groups such as propenyl fluorenyl, terphenylene; pyridyl, furyl, thienyl, pyrrolyl, quinolinyl, isoquinolinyl, benzofuranyl Benzo Thienyl, indolyl, carbazolyl, benzotriazolyl, benzo Aromatic heterocyclic groups such as oxazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, and carbolinyl; styryl, naphthyl Aryl vinyl groups such as vinyl; fluorenyl groups such as ethylfluorenyl and benzamidine; dialkylamino groups such as dimethylamino, diethylamino, and the like; aromatic hydrocarbon groups or condensation such as diphenylamino and dinaphthylamine; Polycyclic aromatic groups substituted disubstituted amino groups; diarylalkylamino groups such as dibenzylamino, diphenylethylamino groups; dipyridylamino groups, dithienylamino groups, etc. substituted by aromatic heterocyclic groups Substituted amine groups; diallylamine groups such as diallylamino groups; two of which are substituted by a substituent selected from alkyl, aromatic hydrocarbon, condensed polycyclic aromatic, aralkyl, aromatic heterocyclic, or alkenyl Substituting groups such as amine groups, these substituents may be further substituted by the substituents exemplified above.

The substituents may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ to form a ring. Here, "N-Ar ₈ " and the "substituted or unsubstituted aromatic hydrocarbon group" and "substituted or unsubstituted aromatic group" represented by Ar ₁ to Ar ₄ in the above general formula (1) "N-Ar ₈ " as defined by "heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" has the same meaning.

As the structural formula (B), (B-1 ), (B-2), (B-3), (B-4), (B ') in the R ₁ ~ R ₈ represents the "which may have a substituent A linear or branched alkyl group having 1 to 6 carbon atoms "," a cycloalkyl group having 5 to 10 carbon atoms that may have a substituent "or" 2 to 6 carbon atoms that may have a substituent "Straight-chain or branched alkenyl groups" in "Straight-chain or branched alkyl groups with 1 to 6 carbon atoms", "Cycloalkyl groups with 5 to 10 carbon atoms" or "2 to 6 carbon atoms""Straight-chain or branched alkenyl", specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, third butyl, n-pentyl, isopentyl , Neopentyl, n-hexyl, cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, vinyl, allyl, isopropenyl and 2-butenyl, etc. A single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ may be bonded to each other to form a ring. Here, "N-Ar ₈ " and the "substituted or unsubstituted aromatic hydrocarbon group" and "substituted or unsubstituted aromatic group" represented by Ar ₁ to Ar ₄ in the above general formula (1) The "N-Ar ₈ " stipulated by "heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" has the same meaning.

The `` substituent carbon '' represented by R ₁ to R _{8 in} structural formulae (B), (B-1), (B-2), (B-3), (B-4), (B ') "Straight-chain or branched alkyl groups having 1 to 6 atoms", "cycloalkyls having 5 to 10 carbon atoms having substituents" or "straight-chain or branching groups having 2 to 6 carbon atoms having substituents" Examples of the "substituent" in the "alkenyl group" include the "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group", or "substituted condensation group" represented by Ar ₁ to Ar ₄ in the general formula (1). The "substituent" disclosed in the "ring aromatic group" is the same, and the same may be cited as the possible forms.

As the structural formula (B), (B-1 ), (B-2), (B-3), (B-4), (B ') in the R ₁ ~ R ₈ represents the "which may have a substituent "Straight-chain or branched alkoxy group having 1 to 6 carbon atoms" or "Cycloalkoxy group having 1 to 6 carbon atoms which may have substituents""Branched or branched alkoxy groups" or "cycloalkoxy groups having 5 to 10 carbon atoms", specifically, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy , Third butoxy, n-pentyloxy, n-hexyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclooctyloxy, 1-adamantyloxy, 2-adamantyloxy, etc. These groups may also be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ to form a ring. Here, "N-Ar ₈ " and the "substituted or unsubstituted aromatic hydrocarbon group" and "substituted or unsubstituted aromatic group" represented by Ar ₁ to Ar ₄ in the above general formula (1) The "N-Ar ₈ " stipulated by "heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" has the same meaning.

The `` substituent carbon '' represented by R ₁ to R _{8 in} structural formulae (B), (B-1), (B-2), (B-3), (B-4), (B ') Examples of the "substituent" in the "linear or branched alkoxy group having 1 to 6" or "the cycloalkoxy group having 5 to 10 carbon atoms having a substituent" include the following general formula (1 ) in the Ar ₁ ~ Ar ₄ represents the "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group" or "substituted condensed polycyclic aromatic group" in the "substituent" for the same are disclosed, could take The same can be cited as the aspect.

As `` substituted or unrepresented '' represented by R ₁ to R _{8 in} structural formulae (B), (B-1), (B-2), (B-3), (B-4), (B ') "Aromatic Hydrocarbyl", "Aromatic Heterocyclic" in "Substituted Aromatic Hydrocarbyl", "Substituted or Unsubstituted Aromatic Heterocyclic Group" or "Substituted or Unsubstituted Condensed Polycyclic Aromatic Group" Group "or" condensed polycyclic aromatic group "includes, for example, the" substituted or unsubstituted aromatic hydrocarbon group "and" substituted or unsubstituted aromatic hydrocarbon group "represented by Ar ₁ to Ar ₄ in the general formula (1). Disclosed by "aromatic hydrocarbon groups", "aromatic heterocyclic groups" or "condensed polycyclic aromatic groups" in "substituted aromatic heterocyclic groups" or "substituted or unsubstituted condensed polycyclic aromatic groups" For the same thing, the same thing can also be mentioned.

The "substituted aromatic hydrocarbon group" represented by R ₁ to R ₈ in the structural formulae (B), (B-1), (B-2), (B-3), (B-4), and (B ') Examples of the "substituent" in the "substituted aromatic heterocyclic group" or the "substituted condensed polycyclic aromatic group" include the "substituted aromatic hydrocarbon group" represented by Ar ₁ to Ar ₄ in the general formula (1). "," Substituted aromatic heterocyclic group "or" Substituted condensed polycyclic aromatic group "for the" substituent "disclosed are the same, and the same may be cited as the possible forms.

As `` substituted or unrepresented '' represented by R ₁ to R _{8 in} structural formulae (B), (B-1), (B-2), (B-3), (B-4), (B ') Specific examples of the "aryloxy group" in the "substituted aryloxy group" include phenoxy, tolyloxy, biphenyloxy, biphenyloxy, naphthyloxy, anthracenyloxy, phenanthryloxy, Fluorenyloxy, indenyloxy, fluorenyloxy, fluorenyloxy, etc. These groups may also be separated by a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ Bonded to each other to form a ring. Here, "N-Ar ₈ " and the "substituted or unsubstituted aromatic hydrocarbon group" and "substituted or unsubstituted aromatic group" represented by Ar ₁ to Ar ₄ in the above general formula (1) "Heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" has the same meaning as "N-Ar ₈ ".

The "substituted aryloxy group" represented by R ₁ to R ₈ in the structural formulae (B), (B-1), (B-2), (B-3), (B-4), and (B ') Examples of the "substituent group" in the general formula (1) include the "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group", or "substituted condensed polycyclic aromatic group" represented by Ar ₁ to Ar ₄ in the general formula (1). The "substituent" disclosed in "" is the same, and the same can be enumerated in the possible modes.

As the "substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted," represented by Ar ₅ , Ar ₆ , and Ar ₇ in the structural formulae (B), (B-2), and (B ') Examples of the "aromatic heterocyclic group" or "substituted or unsubstituted condensed polycyclic aromatic group" include "aromatic hydrocarbon group", "aromatic heterocyclic group" or "condensed polycyclic aromatic group", and Regarding the "substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted aromatic heterocyclic group", or "substituted or unsubstituted aromatic hydrocarbon group" represented by Ar ₁ to Ar ₄ in the above general formula (1) The "aromatic hydrocarbon group", "aromatic heterocyclic group", or "condensed polycyclic aromatic group" in the "substituted condensed polycyclic aromatic group" is the same as those disclosed, and the same can be cited as the possible modes.

The "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group", or "substituted condensed polycyclic ring" represented by Ar ₅ , Ar ₆ , and Ar _{7 in} structural formulae (B), (B-2), and (B ') Examples of the "substituent group" in the "aromatic group" include the "substituted aromatic hydrocarbon group", "substituted aromatic heterocyclic group", or "substituted condensation group" represented by Ar ₁ to Ar ₄ in the general formula (1). The "substituent" disclosed in the "ring aromatic group" is the same, and the same may be cited as the possible forms.

In the general formula (1), n represents an integer of 0 to 4, n is preferably 0, 1 or 2, and more preferably 0 or 1.

In the general formula (1), at least one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is a form of the aforementioned structural formula (B), or at least one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ . It is a state having the aforementioned structural formula (B) as a substituent, or at least one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is the aforementioned structural formula (B) and Ar ₁ , Ar ₂ , Ar ₃ , At least one of Ar ₄ has the aforementioned structural formula (B) as its substituent, and any one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is the aforementioned structural formula (B); Or any one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ having the aforementioned structural formula (B) as a substituent, or any one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ is It is preferable that any one of Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ of the aforementioned structural formula (B) not having the aforementioned structural formula (B) has the aforementioned structural formula (B) as a substituent, and more preferably best of Ar ₁ and Ar ₄ is the aspect of the structural formula (B), the Ar ₁ and Ar ₄ having the foregoing structural formula (B) as an aspect of the substituent of, or Ar ₁ is the structural formula (B) and Ar ₄ having the aforementioned structural formula (B) as a kind of a substituent better state, and more preferably Ar ₁ to Ar ₄ having the aforementioned structure (B-1), (B-3) or (B-4) as a substituent group of aspects or aspects of the structural formula (B-2) of the.

Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ in the general formula (1) are preferably an aromatic hydrocarbon group, a condensed polycyclic aromatic group, the aforementioned structural formula (B), a thienyl group, a benzothienyl group, and a diphenyl group. Benzofuranyl and dibenzothienyl are preferred, and phenyl, biphenyl, bitriphenyl, naphthyl, phenanthryl, fluorenyl, the aforementioned structural formula (B), thienyl, benzothienyl, and diphenyl A benzofuranyl group and a dibenzothienyl group are more preferable, and a phenyl group, a biphenyl group, a fluorenyl group, the aforementioned structural formula (B), a dibenzofuranyl group, and a dibenzothienyl group are particularly preferable.

Ar ₅ , Ar ₆ , Ar _{7 in} structural formulae (B), (B-2), and (B '), aromatic hydrocarbon groups, condensed polycyclic aromatic groups, thienyl, benzothienyl, and dibenzo Furanyl and dibenzothienyl are preferred, phenyl, biphenyl, bitriphenyl, naphthyl, phenanthryl, fluorenyl, thienyl, benzothienyl, dibenzofuranyl, dibenzothiophene Base is more ideal.

In the general formula (1), only one of R ₁ , R ₂ , R ₃ , R ₄ , Ar ₅ , Ar ₆ , and Ar ₇ is a linking group.

In the structural formulae (B) and (B '), X represents a carbon atom or a nitrogen atom, and Y represents a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom. Here, when Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ linking groups or substituents 0 (Ar ₇ does not exist), and when X and Y are nitrogen atoms, then Ar ₅ , Ar ₆ , Any one of Ar ₇ is a linking group or a substituent (any of Ar ₅ , Ar ₆ , and Ar ₇ does not exist), and when X is a nitrogen atom and Y is a carbon atom, then Ar ₅ or Ar ₆ is either One is a linking group or a substituent (any of Ar ₅ and Ar ₆ does not exist).

In structural formulae (B) and (B '), when X is a nitrogen atom, Y is preferably a nitrogen atom. At this time, the linking system of Ar ₅ , Ar ₆ or Ar ₇ and Ar ₁ , Ar ₂ , Ar ₃ , The carbon atom bond of Ar ₄ (the structural formula (B) or (B ') becomes a substituent of Ar ₁ , Ar ₂ , Ar ₃ or Ar ₄ ) is preferable from the viewpoint of the stability of the compound.

In the structural formulae (B) and (B '), when X is a carbon atom, Y is a carbon atom, an oxygen atom, or a sulfur atom, and an oxygen atom or a sulfur atom is more preferable.

In the structural formulae (B) and (B '), the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom is not included in the present invention.

The aromatic amine compound represented by the aforementioned general formula (1) that can be ideally used in the organic EL device of the present invention can be used as a hole injection layer, a hole transport layer, a light emitting layer, an electron blocking layer, or a cover layer of an organic EL device. Use of materials.

In the organic EL device of the present invention, the thickness of the cover layer is preferably in a range of 30 nm to 120 nm, and more preferably in a range of 40 nm to 80 nm.

In the organic EL device of the present invention, when the wavelength of light transmitted through the cover layer is in a range of 450 nm to 750 nm, the refractive index of the cover layer is preferably 1.85 or more, and more preferably 1.90 or more.

In the organic EL device of the present invention, the cover layer can be produced by laminating two or more different constituent materials.

Since the organic EL element of the present invention has a cover layer provided on the outer side of the transparent or translucent electrode with a higher refractive index than the translucent electrode, an organic EL element having a significantly improved light extraction efficiency can be obtained. In addition, by using the aromatic amine compound represented by the general formula (1) in the cover layer, a film can be formed at a temperature of 400 ° C. or lower, so that a high-precision mask can be used without damaging the light-emitting element, so that the light of each color can be extracted. It is optimized and suitable for full-color displays. It can display bright and bright images with good color purity.

Since the organic EL element of the present invention uses a material for an organic EL element with a high refractive index, excellent film stability, and durability as a material for the cover layer, compared with the conventional organic EL element, the light extraction efficiency can be greatly improved. improve. Furthermore, an organic EL element with high efficiency and long life can be achieved.

1‧‧‧ glass substrate

2‧‧‧ metal anode

3‧‧‧ Hole injection layer

4‧‧‧ Hole transporting layer

5‧‧‧ luminescent layer

6‧‧‧ electron transport layer

7‧‧‧ electron injection layer

8‧‧‧ cathode

9‧‧‧ overlay

FIG. 1 shows a ¹ H-NMR chart of the compound (1-1) of Example 1 of the present invention.

Fig. 2 shows a ¹ H-NMR chart of the compound (1-32) of Example 2 of the present invention.

Fig. 3 shows a ¹ H-NMR chart of the compound (1-2) of Example 3 of the present invention.

Fig. 4 shows a ¹ H-NMR chart of the compound (1-22) of Example 4 of the present invention.

Fig. 5 shows a ¹ H-NMR chart of the compound (1-23) of Example 5 of the present invention.

Fig. 6 shows a ¹ H-NMR chart of the compound (1-25) of Example 6 of the present invention.

FIG. 7 shows the structures of the organic EL elements of Examples 10 to 13 and Comparative Example 1. FIG.

The aromatic amine compound represented by the aforementioned general formula (1) that can be preferably used for the organic EL device of the present invention is a novel compound, and these compounds can be synthesized, for example, in the following manner. For example: from a 1,2-diaminobenzene derivative and a nitroaryl derivative, a 2-aminoarylazobenzene derivative is synthesized by a known method, and a bis (acetate-O) phenyl group is implemented An oxidative cyclization reaction of bis (acetato-O) phenyliodine can synthesize a benzotriazole derivative having an aryl group (see, for example, Non-Patent Document 4).

Here, by using a 1,2-diaminobenzene derivative or a nitroaryl derivative having a halogen atom such as a bromine atom as a substituent, a bromine substitute of an benzotriazole derivative having an aryl group can be synthesized. . Then, borrow The arylamine compound represented by the general formula (1) of the present invention can be synthesized by performing a condensation reaction such as a Ullmann reaction, a Buchwald-Hartwig reaction, and the like of the bromine substituted body with a diarylamine.

Furthermore, by performing bromination using the N-bromosuccinic acid imine or the like on the synthetic benzotriazole derivative having an aryl group, a brominated benzotriazole derivative can also be synthesized. Here, by changing the bromination reagent and conditions, bromine substitutes having different substitution positions can be obtained. In addition, by performing the same reaction, an aromatic amine compound represented by the general formula (1) of the present invention can be synthesized.

In addition, for this bromine substitution, boronic acid or boronic acid derivative derived from the reaction of various arylhalides with pinacol borane or bis (pinacolato) diboron is carried out and implemented. Cross-coupling reactions such as Suzuki coupling (for example, refer to Non-Patent Document 5) (for example, refer to Non-Patent Document 6) can also be used to synthesize an aromatic amine compound represented by the general formula (1) of the present invention.

In addition, a cross-coupling reaction such as Suzuki coupling with various arylhalanes having a diarylamino group is obtained by synthesizing a boronic acid or boronic acid ester derivative from the bromine substituent (for example, refer to Non-Patent Document 5) (For example, refer to Non-Patent Document 6) An aromatic amine compound represented by the general formula (1) of the present invention can also be synthesized.

Here, with respect to benzothiazole derivatives and benzo An azole derivative, or a bromine substitute of an indole derivative, or a bromine substituted after bromination, can be synthesized by performing the same reaction to have benzothiazolyl and benzo An azole group or an indolyl group is an aromatic amine compound represented by the general formula (1) of the present invention.

Among the aromatic amine compounds represented by the aforementioned general formula (1) that can be preferably used for the organic EL device of the present invention, specific examples of the particularly desirable compounds are shown below, but are not limited to these compounds.

[Chem 34]

[Chemical 39]

[Chemical 49]

The purification of these compounds is carried out using column chromatography, purification using silica gel, activated carbon, activated clay, etc., recrystallization or crystallization using solvents, etc. Hua Refining and other refining. In terms of physical property values, the measurement of the glass transition point (Tg) and the refractive index are performed. The glass transition point (Tg) is an index about the stability of the film state, and the refractive index is an index about the improvement of light extraction efficiency.

The glass transition point (Tg) was measured using a powder using a high-sensitivity differential scanning calorimeter (DSC3100S manufactured by BRUKER AXS).

The refractive index was formed on a silicon substrate with a film of 80 nm, and was measured using a spectrophotometer (F10-RT-UV manufactured by Filmetrics).

The structure of the organic EL element of the present invention, for example, in the case of a light-emitting element with a top-emitting structure, has an anode made of metal, a hole transport layer, a light-emitting layer, an electron transport layer, a translucent cathode, and Covered layer, and a hole injection layer between the anode and the hole transporting layer, an electron blocking layer between the hole transporting layer and the light emitting layer, and an electricity between the light emitting layer and the electron transporting layer The hole blocking layer has an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, several organic layers may be omitted or used in combination. For example, they may have a structure that functions as a hole transporting layer and an electron blocking layer and a structure that also functions as an electron transporting layer and a hole blocking layer. The film thickness of each layer of the organic EL element is preferably about 200 nm to 750 nm, and more preferably about 350 nm to 600 nm. The film thickness of the cover layer is, for example, preferably 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 cover layer can be appropriately changed according to the type of the light-emitting material used in the light-emitting element, the thickness of the organic EL element other than the cover layer, and the like.

As the anode of the organic EL element of the present invention, an electrode material having a large work function such as ITO or gold can be used.

As the hole injection layer of the organic EL element of the present invention, an aromatic amine compound having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group containing no hetero atom can be used, for example, a light-emitting type Materials such as triphenylamine derivatives, various triphenylamine tetramers, or polyporphyrin compounds represented by copper phthalocyanine, acceptor-like heterocyclic compounds such as hexacyanoazatriphenylene, and coating type Polymer materials, etc. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

As the hole transporting layer of the organic EL element of the present invention, for example, N, N'-diphenyl-N, N'-bis (m-tolyl) benzidine (hereinafter referred to as TPD), N, N'- Diphenyl-N, N'-bis (α-naphthyl) benzidine (NPD), 1,1-bis [4- (di-4-tolylamino) phenyl] cyclohexane (TAPC), especially In the molecule, there are aromatic amine compounds having a structure in which two triphenylamine structures are connected by a single bond or a divalent group containing no heteroatom, such as N, N, N ', N'-terphenylphenylbenzidine, etc. . In addition, an aromatic amine compound having a structure in which three or more triphenylamine structures are connected by a single bond or a divalent group containing no heteroatoms, such as various triphenylamine trimers and tetramers, is preferred. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

In the hole injection layer or the hole transport layer, a material generally used for the layer may be further doped with p-type bromoaniline hexachloroantimony or the like, and a structure having a benzidine derivative such as TPD as a secondary structure. Polymer compounds.

As the electron blocking layer of the organic EL element of the present invention, 4,4 ', 4 "-tris (N-carbazolyl) 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), 2,2-bis (4-carbazole-9-ylphenyl) adamantane (Ad -Cz) and other carbazole derivatives, 9- [4- (carbazole-9-yl) phenyl] -9- [4- (triphenylsilyl) phenyl] -9H-fluorene is represented by triphenyl Compounds with electron blocking function, such as silicon-based compounds and triarylamine structures. These can be formed alone or mixed with other materials to form a single layer, or the layers can be formed separately and mixed with each other. The layered structure of each of the film-forming layers, or a layer formed of a single film and a layer of a mixed film. In addition to the vapor deposition method, these materials can also be formed into a thin film by a known method such as a spin coating method or an inkjet method.

As the light-emitting layer of the organic EL device of the present invention, metal complexes of quinolinol derivatives such as Alq ₃ , complexes of various metals, anthracene derivatives, bisstyrylbenzene derivatives, and fluorene derivatives can be used. , An azole derivative, a polyparaphenylene vinylene derivative, and the like. The light-emitting layer may be composed of a host material and a dopant material. As the host material, in addition to the above-mentioned light-emitting material, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, or the like may be used. As the dopant material, quinacridone, coumarin, rubrene, fluorene, and derivatives thereof, benzopiperan derivatives, rhodamine derivatives, aminostyryl derivatives, and the like can be used. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

Furthermore, a phosphorescent light emitting material may be used as the light emitting material. As the phosphorescent light-emitting material, a phosphorescent light-emitting body of a metal complex such as iridium or platinum can be used. For example: green phosphorescent emitters such as Ir (ppy) ₃ , blue phosphorescent emitters such as FIrpic, FIr6, red phosphorescent emitters such as Btp ₂ Ir (acac), and the like. As the host material thus produced, as for the hole injection / transportation host material, 4,4'-bis (N-carbazolyl) biphenyl (CBP) or carbazole derivatives such as TCTA and mCP can be used. As the host material for electron transportability, p-bis (triphenylsilyl) benzene (UGH2), 2,2 ', 2 "-(1,3,5-phenylene) -ginsyl (1-phenyl) -1H-benzimidazole) (TPBI), etc., can be made into high-performance organic EL devices.

The doping of the phosphorescent light-emitting material to the host material is preferably in the range of 1-30% by weight for the entire light-emitting layer in order to avoid concentration extinction. It is better to dope by co-evaporation.

As the light-emitting material, a material that emits delayed fluorescence such as CDCB derivatives such as PIC-TRZ, CC2TA, PXZ-TRZ, and 4CzIPN can be used (for example, refer to Non-Patent Document 7).

These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method, in addition to the vapor deposition method.

Examples of the hole layer of the organic EL device of the present invention include morpholine derivatives such as Bathocuproin, and bis (2-methyl-8-quinolinol) -4-phenylphenolate ( III) Metal complexes of quinolinol derivatives such as BAlq (hereinafter referred to as BAlq), various rare earth complexes, triazole derivatives, derivative, Diazole derivatives and other compounds that have hole blocking effects. These materials may also serve as materials for the electron transport layer. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

As the electron transport layer of the organic EL element of the present invention, metal complexes of quinolinol derivatives such as Alq ₃ and BAlq, various metal complexes, triazole derivatives, derivative, Diazole derivatives, thiadiazole derivatives, pyridoindole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, silyl derivatives, and the like. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

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, and metal oxides such as alumina can be used. The ideal choice can be omitted.

In addition, as the electron injection layer or the electron transport layer, a material generally used for the layer may be further doped with a metal such as cesium.

The translucent cathode of the organic EL element of the present invention can use an electrode material with a low work function such as aluminum, or an alloy with a lower work function such as magnesium-silver alloy, magnesium-calcium alloy, magnesium-indium alloy, aluminum-magnesium alloy, or ITO. And IZO as electrode materials.

As the covering layer of the organic EL device of the present invention, an aromatic amine compound or the like represented by the aforementioned general formula (1) is preferably used. These can be formed separately, or mixed with other materials to form a single layer. It can also be used as a single layer, mixed layers, or layers. Layered structure. These materials may be formed into a thin film by a known method such as a spin coating method or an inkjet method in addition to the vapor deposition method.

In addition, the organic EL element having the top emission structure has been described above, but the present invention is not limited to this. The same applies to the organic EL element having the bottom emission structure or the organic EL element having a dual emission structure that emits light in both directions from the top and the bottom. Applicable. In such cases, the electrodes located in a direction to extract light from the light emitting element to the outside must be transparent or translucent.

The refractive index of the material constituting the cover layer is preferably larger than that of the adjacent electrodes. That is, the use of the cover layer improves the light extraction efficiency of the organic EL element. However, in terms of its effect, when the reflectance at the interface between the cover layer and the material contacting the cover layer is large, the effect of light interference is large, so it is effective. . Therefore, the refractive index of the material constituting the cover layer should be larger and more ideal than that of the adjacent electrode, and the refractive index may be 1.70 or more, but 1.80 or more is preferable, and 1.85 or more is particularly preferable.

The following specifically describes the embodiments of the present invention using examples, but the present invention is not limited to the following examples.

[Example 1]

<N, N'-bis {4- (2H-benzo [1,2,3] triazol-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamine Synthesis of -1,1'-biphenyl (Compound (1-1))>

In a reaction vessel substituted with nitrogen, 4.2-g of 4- (4-bromophenyl) -2H-benzo [1,2,3] triazole, 2.3g of N, N'-diphenylbenzidine, and 2.0 g of sodium butoxide, 50 ml of toluene was added, and nitrogen was introduced while irradiating with ultrasound for 30 minutes. 62.0 mg of palladium acetate and 0.2 ml of tri-tert-butylphosphine were added, and the mixture was heated at 91 ° C. for 5 hours. After cooling to room temperature, 50 ml of toluene was added, and the organic layer was collected by an extraction operation. The organic layer was concentrated, purified by column chromatography (support: NH silica gel, eluent: toluene / n-hexane), and then subjected to dispersion washing with 100 ml of n-hexane to obtain N, N'-bis {4- (2H -Benzo [1,2,3] triazol-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (Compound (1 -1)) 3.3 g of yellow powder (yield 66%).

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

¹ H-NMR (THF-d ₈ ) detected the following 34 hydrogen signals.

δ (ppm) = 8.26 (4H), 7.89 (4H), 7.60 (4H), 7.39 (4H), 7.33 (4H), 7.24 (4H), 7.21 (8H), 7.10 (2H).

[Example 2]

<N, N'-bis (2-phenyl-2H-benzo [1,2,3] triazol-5-yl) -N, N'-diphenyl-4,4'-diamino- Synthesis of 1,1'-biphenyl (Compound (1-32))>

In a reaction vessel substituted with nitrogen, add 4.1 g of 5-bromo-2-phenyl-2H-benzo [1,2,3] triazole, 2.3 g of N, N'-diphenylbenzidine, and tert-butyl 2.0 g of sodium alkoxide, 50 ml of toluene was added, and nitrogen was introduced while irradiating with ultrasound for 30 minutes. 62.0 mg of palladium acetate and 0.2 ml of tri-tert-butylphosphine were added and heated. Stir at 91 ° C for 3.5 hours. After cooling to room temperature, 50 ml of toluene was added, and the organic layer was collected by an extraction operation. The organic layer was concentrated and purified by column chromatography (support: silica gel, eluent: toluene / n-hexane). After 25 ml of THF was added and dissolved, 100 ml of methanol was added dropwise to perform crystallization and purification to obtain N, N'-bis (2-phenyl-2H-benzo [1,2,3] triazol-5-yl) -N 4.0 g of yellow-brown powder of, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (compound (1-32)) (yield: 80%).

The structure of the obtained yellow-brown powder was identified using NMR.

¹ H-NMR (THF-d ₈ ) detected the following 34 hydrogen signals.

δ (ppm) = 8.32 (4H), 7.81 (2H), 7.59 (4H), 7.54 (4H), 7.43 (2H), 7.40 (2H), 7.32 (4H), 7.28 (2H), 7.20 (4H), 7.18 (4H), 7.09 (2H).

[Example 3]

<N, N'-bis {4- (2H-benzo [1,2,3] triazol-2-yl) phenyl} -N, N'-diphenyl-4,4 "-diamine Synthesis of -1,1 ': 4', 1 "-bitriphenyl (Compound (1-2))>

In a reaction vessel substituted with nitrogen, 4,4 "-diiodo-1,1 ': 4', 1" -bitriphenyl 14.0g, {4- (2H-benzo [1,2,3] triphenyl) Azol-2-yl) phenyl} aniline 18.3 g, potassium carbonate 13.2 g, copper powder 0.3 g, sodium bisulfite 0.9 g, 3,5-di-tert-butylsalicylic acid 0.7 g, dodecylbenzene 30ml and heated, and stirred at 210 ° C for 44 hours. After cooling to room temperature, 50 ml of toluene was added, and the precipitate was collected by filtration. 230 ml of 1,2-dichlorobenzene was added to the precipitate, dissolved by heating, and insoluble matter was removed by hot filtration. The filtrate was concentrated, purified by crystallization using 1,2-dichlorobenzene, and then dispersed and washed with methanol to obtain N, N'-bis {4- (2H-benzo [1,2,3] triazole). -2-yl) phenyl} -N, N'-diphenyl-4,4 "-diamino-1,1 ': 4', 1" -bitriphenyl (Compound (1-2)) 22.2 g of yellow powder (96% yield).

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

¹ H-NMR (CDCl ₃ ) detected the following 38 hydrogen signals.

δ (ppm) = 8.24 (4H), 7.99-7.92 (4H), 7.72-7.58 (7H), 7.50-7.12 (23H).

[Example 4]

<N, N'-bis (4- (benzo Azol-2-yl) phenyl} -N, N'-diphenyl-4,4 "-diamino-1,1 ': 4', 1" -bitriphenyl (Compound (1-22)) Synthesis>

{4- (2H-benzo [1,2,3] triazol-2-yl) phenyl} aniline in Example 3 was replaced with {4- (benzo Azol-2-yl) phenyl} aniline was reacted under the same conditions to obtain N, N'-bis {4- (benzo Azol-2-yl) phenyl} -N, N'-diphenyl-4,4 "-diamino-1,1 ': 4', 1" -bitriphenyl (Compound (1-22)) Yellow powder 12.4 g (47% yield).

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

¹ H-NMR (CDCl ₃ ) detected the following 38 hydrogen signals.

δ (ppm) = 8.13 (4H), 7.80-7.55 (11H), 7.50-7.16 (23H).

[Example 5]

<N, N'-bis (4- (benzo Synthesis of azole-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (compound (1-23))>

Replace 2- (4-bromophenyl) -2H-benzo [1,2,3] triazole in Example 1 with 2- (4-bromophenyl) -benzo Azole, reacted under the same conditions to obtain N, N'-bis {4- (benzo Azol-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (compound (1-23)) as a pale yellow powder 8.8 g (54% yield).

The structure of the obtained pale yellow powder was identified using NMR.

¹ H-NMR (CDCl ₃ ) detected the following 34 hydrogen signals.

δ (ppm) = 8.12 (4H), 7.80-7.72 (2H), 7.60-7.53 (5H), 7.41-7.14 (23H).

[Example 6]

<N, N'-bis {4- (benzothiazol-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (compound (1-25)) Synthesis>

The 2- (4-bromophenyl) -2H-benzo [1,2,3] triazole in Example 1 was replaced with 2- (4-bromophenyl) -benzothiazole, and the same conditions were used. Reaction to obtain N, N'-bis {4- (benzothiazol-2-yl) phenyl} -N, N'-diphenyl-4,4'-diamino-1,1'-biphenyl (Compound (1-25)) 9.3 g of light yellow powder (62% yield).

The structure of the obtained pale yellow powder was identified using NMR.

¹ H-NMR (CDCl ₃ ) detected the following 34 hydrogen signals.

δ (ppm) = 8.10-7.88 (8H), 7.60-7.13 (26H).

[Example 7]

<N, N'-bis {4- (benzothiazol-2-yl) phenyl} -N, N'-diphenyl-4,4 "-diamino-1,1 ': 4', 1 "-Synthesis of Bistriphenyl (Compound (1-27))>

In a reaction vessel substituted with nitrogen, 9.3 g of N- {4- (benzothiazol-2-yl) phenyl} aniline, 4,4 "-diiodo-1,1 ': 4', 1" -linked 7.1 g of tribenzene, 4.6 g of sodium tert-butoxide, and 140 ml of toluene were irradiated with nitrogen while irradiating with ultrasound for 30 minutes. 0.20 g of palladium acetate and 0.5 g of a 50% (v / v) toluene solution of third butylphosphine were added, and the mixture was heated and refluxed for 3 hours while stirring. After cooling to room temperature, the precipitate was collected by filtration, and then repeatedly purified by crystallization using a mixed solvent of 1,2-dichlorobenzene / methanol to obtain N, N'-bis {4- (benzothiazol-2-yl) Phenyl} -N, N'-diphenyl-4,4 ”-diamino-1,1 ': 4', 1” -bitriphenyl (compound (1-27)) green powder 7.0g (Yield 58%).

[Example 8]

The glass transition point of the compound of the present invention was determined using a high-sensitivity differential scanning calorimeter (DSC3100S manufactured by BRUKER AXS).

The compound of the present invention has a glass transition point of 100 ° C or higher. This shows that the compound of the present invention is stable in a thin film state.

[Example 9]

Using the compound of the present invention, a vapor-deposited film having a film thickness of 80 nm was formed on a silicon substrate, and a refractive index at 633 nm was measured using a spectrophotometer (F10-RT-UV manufactured by Fillmetrics). For comparison, the comparative compounds (2-1), (2-2), and Alq _{3 of the} following structural formulas were also measured (for example, refer to Patent Document 3).

As described above, the compound of the present invention has a larger refractive index than the comparative compounds (2-1), (2-2), and Alq ₃ from 1.70 to 1.81, and it is expected that the light extraction efficiency in the organic EL device will be improved.

[Example 10]

As shown in FIG. 7, the organic EL element is formed on a glass substrate 1 with a reflective ITO electrode serving as a metal anode 2 in advance, and sequentially deposits a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, The electron transport layer 6, the electron injection layer 7, the cathode 8, and the cover layer 9 are made.

Specifically, the glass substrate 1 having an ITO film having a thickness of 150 nm was ultrasonically washed in isopropyl alcohol for 20 minutes, heated to 250 ° C., and dried on a hot plate for 10 minutes. Thereafter, a UV ozone treatment was performed for 2 minutes, and then the ITO-attached glass substrate was mounted in a vacuum evaporation machine, and the pressure was reduced to 0.001 Pa or less. Then, the compound (HIM-1) of the following structural formula was formed as a hole injection layer 3 so as to cover the metal anode 2. On the hole injection layer 3, a film of the aforementioned comparative compound (2-1) was formed to a thickness of 70 nm, and the hole transport layer 4 was formed. On this hole transporting layer 4, the compound EMD-1 (NUBD370 manufactured by SFC Corporation) and the compound EMH-1 (ABF113 manufactured by SFC Corporation) become EMD-1 at a vapor deposition rate ratio: EMH- Binary vapor deposition was performed at a vapor deposition rate of 1 = 5: 95, so that the film thickness was 25 nm, and the light-emitting layer 5 was used. On the light-emitting layer 5, the compound (ETM-1) of the following structural formula and the compound (ETM-2) of the following structural formula are (ETM-1) at a vapor deposition rate ratio: (ETM-2) = 50: 50 evaporation Binary vapor deposition was performed at a rate such that the film thickness was 30 nm, and the electron transport layer 6 was used. A film of lithium fluoride was formed on this electron transporting layer 6 to have a film thickness of 0.5 nm as the electron injection layer 7. A film of a magnesium-silver alloy was formed on the electron injection layer 7 to have a film thickness of 14 nm as the cathode 8. Finally, a film of the compound (1-1) of Example 1 was formed so as to have a film thickness of 60 nm as the cover layer 9. For the produced organic EL element, characteristics were measured in the atmosphere at room temperature.

The measurement results of the light emission characteristics when a DC voltage was applied to the produced organic EL device are summarized in Table 1.

[Example 11]

The compound (1-1) of Example 1 in Example 10 was replaced with a film of the compound (1-32) of Example 2 An organic EL device was fabricated under the same conditions as the cover layer 9 except that the film thickness was 60 nm. For the produced organic EL element, characteristics were measured in the atmosphere at room temperature. The measurement results of the light-emitting characteristics when a DC voltage was applied to the produced organic EL device are summarized in Table 1.

[Example 12]

The compound (1-1) of Example 1 in Example 10 was replaced with the compound (1-2) of Example 3, and a film having a film thickness of 60 nm was used as the cover layer 9, and an organic EL was produced under the same conditions. element. For the produced organic EL element, characteristics were measured in the atmosphere at room temperature. The measurement results of the light-emitting characteristics when a DC voltage was applied to the produced organic EL device are summarized in Table 1.

[Example 13]

The compound (1-1) of Example 1 in Example 10 was replaced with the compound (1-22) of Example 4, and a film having a film thickness of 60 nm was used as the cover layer 9, and an organic EL was produced under the same conditions. element. For the produced organic EL element, characteristics were measured in the atmosphere at room temperature. The measurement results of the light-emitting characteristics when a DC voltage was applied to the produced organic EL device are summarized in Table 1.

[Comparative Example 1]

For comparison, the compound (1-1) of Example 1 in Example 10 was replaced with Alq ₃ , and a film having a thickness of 60 nm was used as the cover layer 9. An organic EL device was fabricated under the same conditions. For the produced organic EL element, characteristics were measured in the atmosphere at room temperature. Table 1 shows the measurement results of the light-emitting characteristics of the produced organic EL device when a DC voltage was applied.

【Table 1】

As shown in Table 1, regarding the driving voltage at a current density of 10 mA / cm ² , the element (4.19V) of Comparative Example 1 using Alq ₃ is approximately the same as the element (4.17 to 4.18V) of Examples 10 to 13, and Here, regarding the brightness, luminous efficiency, and power efficiency, compared to the element of Comparative Example 1 using Alq ₃ (luminous efficiency: 5.13 cd / A, power efficiency: 3.78 lm / W), the elements of Examples 10 to 13 ( Luminous efficiency: 5.31 ~ 5.36cd / A, power efficiency: 3.98 ~ 4.06lm / W). In particular, it was confirmed that the external quantum efficiency was significantly improved compared to the element of Comparative Example 1 (10.72%), and the elements of Examples 10 to 13 (11.41 to 11.93%). This shows that the cover layer can greatly improve light extraction efficiency by containing a material having a high refractive index and suitable for the organic EL element of the present invention.

[Industrial availability]

As described above, the organic EL device of the present invention can be ideally used for the aromatic amine compound represented by the general formula (1), which has a high refractive index, can greatly improve the extraction efficiency of light, and has a stable thin film state. Excellent compound. By using this compound to produce an organic EL element, high efficiency can be obtained, and durability can also be improved. In addition, the use of the compound without absorption in each of the blue, green, and red wavelength regions is particularly preferable when displaying bright and bright images with good color purity. For example, it can be used for home appliances or lighting.

Claims (11)

An organic electroluminescent element has at least an anode electrode, a hole transport layer, a light emitting layer, an electron transport layer, a cathode electrode, and a cover layer in sequence, the cover layer containing an aromatic amine compound represented by the following general formula (1);

In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ may be the same or different from each other, which means a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted Substituted condensed polycyclic aromatic group, n represents an integer of 0 ~ 4; here, at least one of Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ is a monovalent group represented by the following structural formula (B); Except that the structural formula (B) is the following structural formulas (B-1), (B-2), (B ');

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a linking group, a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or may have a substituent Straight-chain or branched alkyl groups with 1 to 6 carbon atoms, may also have a cycloalkyl group with 5 to 10 carbon atoms for substituents, or may have a straight chain with 2 to 6 carbon atoms for substituents or A branched alkenyl group, which may have a linear or branched alkoxy group having 1 to 6 carbon atoms in the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms in the substituent, substituted or unsubstituted Substituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, substituted or unsubstituted condensed polycyclic aromatic groups, or substituted or unsubstituted aryloxy groups, and may also A single bond, substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; X represents a carbon atom or nitrogen atom, Y represents a carbon atom, oxygen atom, sulfur atom, or a nitrogen atom, Ar ₅ represents a substituted or non-substituted aromatic hydrocarbon group, substituted or non-substituted aromatic heterocyclic group, or by taking Or a non-substituted condensed polycyclic aromatic group, or a linking group, Ar _6, Ar ₇ may be identical to or different from each other and is a substituted or non-substituted aromatic hydrocarbon group, substituted or non-substituted aromatic heterocyclic When a cyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group, or a linking group, and Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ 0, and X and Y are nitrogen atoms, then Any one of Ar ₅ , Ar ₆ , and Ar ₇ is a substituent or a linking group, when X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ become 0; Ar ₈ represents substituted or unsubstituted Aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic groups; but R ₁ , R ₂ , R ₃ , R ₄ , Ar ₅ , Ar _6. Only one of Ar ₇ is a linking group, and the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom is excluded;

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom which may have a substituent 1 Straight-chain or branched alkyl group up to 6, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent , May also have a linear or branched alkoxy group having 1 to 6 carbon atoms for the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms for the substituent, substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and may also be separated by a single bond, Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic groups;

In the formula, R ₁ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom having 1 to 6 substituents Straight-chain or branched alkyl group, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight-chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent, or Straight-chain or branched alkoxy groups having 1 to 6 carbon atoms with substituents, or cycloalkoxy groups having 5 to 10 carbon atoms with substituents, substituted or unsubstituted aromatic hydrocarbon groups, Substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and R ₃ and R ₄ may also be separated by a single Bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms or N-Ar ₈ are bonded to each other to form a ring; Ar ₆ and Ar ₈ may be the same or different from each other, indicating substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group; [Chem 5]

In the formula, R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ may be the same or different from each other, and are a linking group, or a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, It may have a linear or branched alkyl group having 1 to 6 carbon atoms for the substituent, a cycloalkyl group having 5 to 10 carbon atoms for the substituent, or 2 to 2 carbon atoms for the substituent 6 straight-chain or branched alkenyl groups, may also have substituents with 1 to 6 carbon atoms or straight-chain or branched alkoxy groups, or may have substituents with 5 to 10 carbon atoms Group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group Group, and can also be bonded to each other through a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ ; X represents a carbon atom or a nitrogen atom, and Y represents a carbon atom, an oxygen atom, a sulfur atom, or a nitrogen atom, Ar ₅ represents a substituted or non-substituted aromatic hydrocarbon group, substituted or non-substituted aromatic heterocyclic , Or substituted or non-substituted condensed polycyclic aromatic group, or a linking group, Ar _6, Ar ₇ may be identical to or different from each other and is a substituted or non-substituted aromatic hydrocarbon group, a substituted or unsubstituted Aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group, or linking group, when Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ 0, X and Y are nitrogen atoms , Any one of Ar ₅ , Ar ₆ , and Ar ₇ is a substituent or a linking group, when X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ become 0; Ar ₈ represents substituted or Unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group; except R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ , Ar ₅ , Ar ₆ , and Ar ₇ have only one of them as a linking group, and exclude the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom. For example, the organic electroluminescent device according to item 1 of the patent application, wherein the structural formula (B) is a monovalent group represented by the following structural formula (B-3);

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom which may have a substituent 1 Straight-chain or branched alkyl group up to 6, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent , May also have a linear or branched alkoxy group having 1 to 6 carbon atoms for the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms for the substituent, substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and may also be separated by a single bond, Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group. For example, the organic electroluminescent device of the first patent application, wherein the structural formula (B) is a monovalent group represented by the following structural formula (B-4); [Chemical 7]

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom which may have a substituent 1 Straight-chain or branched alkyl group up to 6, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent , May also have a linear or branched alkoxy group having 1 to 6 carbon atoms for the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms for the substituent, substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and may also be separated by a single bond, Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group. For example, in the organic electroluminescent device according to item 1 of the patent application, in the general formula (1), n is 0. For example, in the organic electroluminescent device according to item 1 of the patent application, in the general formula (1), n is 1. For example, in the organic electroluminescent device according to item 1 of the patent application, in the general formula (1), n is 2. An organic electroluminescence device as claimed in item 1 of the patent scope, wherein in the general formula (1), any one of Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ is represented by the structural formula (B) 1 Price base. For example, in the organic electroluminescent device according to item 1 of the patent application, in the general formula (1), Ar ₁ and Ar _{4 are} monovalent groups represented by the structural formula (B). For example, the organic electroluminescent device of the first patent application, wherein the thickness of the cover layer is in the range of 30nm ~ 120nm. For example, in the organic electroluminescent device of claim 1, the refractive index of the cover layer is 1.85 or more in the range of 450 nm to 750 nm of the wavelength of light transmitted through the cover layer. A method for manufacturing an organic electroluminescent element, characterized in that an anode electrode, a hole transport layer, a light emitting layer, an electron transport layer, a cathode electrode and a cover layer are formed at least in sequence, and the compound represented by the following general formula (1) As the cover layer;

In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ may be the same or different from each other, which means a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted Substituted condensed polycyclic aromatic group, n represents an integer of 0 ~ 4; here, at least one of Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ is a monovalent group represented by the following structural formula (B); Except that the structural formula (B) is the following structural formulas (B-1), (B-2), (B ');

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a linking group, a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or may have a substituent Straight-chain or branched alkyl groups with 1 to 6 carbon atoms, may also have a cycloalkyl group with 5 to 10 carbon atoms for substituents, or may have a straight chain with 2 to 6 carbon atoms for substituents or A branched alkenyl group, which may have a linear or branched alkoxy group having 1 to 6 carbon atoms in the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms in the substituent, substituted or unsubstituted Substituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, substituted or unsubstituted condensed polycyclic aromatic groups, or substituted or unsubstituted aryloxy groups, and may also A single bond, substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; X represents a carbon atom or nitrogen atom, Y represents a carbon atom, oxygen atom, sulfur atom, Or a nitrogen atom, Ar ₅ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group, or a linking group, Ar ₆ and Ar ₇ may be the same or different from each other and are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic groups When Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ 0, and when X and Y are nitrogen atoms, any one of Ar ₅ , Ar ₆ , and Ar ₇ is a substituent , Or a linking group, when X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ become 0; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic ring Group, or a substituted or unsubstituted condensed polycyclic aromatic group; but only one of R ₁ , R ₂ , R ₃ , R ₄ , Ar ₅ , Ar ₆ , Ar ₇ is a linking group, and X is excluded Is a nitrogen atom and Y is an oxygen atom or a sulfur atom;

In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom which may have a substituent 1 Straight-chain or branched alkyl group up to 6, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent , May also have a linear or branched alkoxy group having 1 to 6 carbon atoms for the substituent, or a cycloalkoxy group having 5 to 10 carbon atoms for the substituent, substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and may also be separated by a single bond, Substituted or unsubstituted methylene, oxygen atom, sulfur atom or N-Ar ₈ are bonded to each other to form a ring; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic Heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic groups;

In the formula, R ₁ , R ₃ , and R ₄ may be the same or different from each other, and are a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, or a carbon atom having 1 to 6 substituents Straight-chain or branched alkyl group, may have a cycloalkyl group having 5 to 10 carbon atoms as a substituent, or may have a straight-chain or branched alkenyl group having 2 to 6 carbon atoms as a substituent, or Straight-chain or branched alkoxy groups having 1 to 6 carbon atoms with substituents, or cycloalkoxy groups having 5 to 10 carbon atoms with substituents, substituted or unsubstituted aromatic hydrocarbon groups, Substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group, and R ₃ and R ₄ may also be separated by a single Bonds, substituted or unsubstituted methylene groups, oxygen atoms, sulfur atoms or N-Ar ₈ are bonded to each other to form a ring; Ar ₆ and Ar ₈ may be the same or different from each other, indicating substituted or unsubstituted aromatic Group hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group;

In the formula, R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ may be the same or different from each other, and are a linking group, or a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, It may have a linear or branched alkyl group having 1 to 6 carbon atoms for the substituent, a cycloalkyl group having 5 to 10 carbon atoms for the substituent, or 2 to 2 carbon atoms for the substituent 6 straight-chain or branched alkenyl groups, may also have substituents with 1 to 6 carbon atoms or straight-chain or branched alkoxy groups, or may have substituents with 5 to 10 carbon atoms Group, substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted aromatic heterocyclic group, substituted or unsubstituted condensed polycyclic aromatic group, or substituted or unsubstituted aryloxy group Group, and can also be bonded to each other through a single bond, a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, or N-Ar ₈ ; X represents a carbon atom or a nitrogen atom, and Y represents a carbon atom, Oxygen atom, sulfur atom, or nitrogen atom, Ar ₅ represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group Group or linking group, Ar ₆ and Ar ₇ may be the same or different from each other and are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted The condensed polycyclic aromatic group or linking group, when Y is an oxygen atom or a sulfur atom, Y makes the number of Ar ₇ 0, and X and Y are nitrogen atoms, then any of Ar ₅ , Ar ₆ , Ar ₇ One is a substituent or a linking group, when X is a nitrogen atom and Y is a carbon atom, X makes the number of Ar ₆ become 0; Ar ₈ represents a substituted or unsubstituted aromatic hydrocarbon group, substituted or unsubstituted Aromatic heterocyclic group, or substituted or unsubstituted condensed polycyclic aromatic group; but R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ , Ar ₅ , Ar ₆ , Ar ₇ only Either is a linking group, and excludes the case where X is a nitrogen atom and Y is an oxygen atom or a sulfur atom.