JP2013191649A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element which has high luminous efficiency, excellent stability of element performance, and a long service life.SOLUTION: The organic electroluminescent element having a light-emitting layer between an anode and a cathode comprises a first hole injection layer, an acceptor layer, and a second hole injection layer in order between the anode and the light-emitting layer. The first hole injection layer contains an aromatic amine derivative having a specific substituent containing a thiophene structure.

Description

  The present invention relates to a specific organic electroluminescence (EL) device configuration, specifically a device including an acceptor layer between an anode and a light emitting layer, and a specific aromatic amine derivative between the acceptor layer and the anode. It is related with the organic EL element which shows the stable and favorable positive hole injection characteristic by setting it as the structure which provided the layer containing this.

  An organic EL element is a self-luminous element utilizing the principle that a fluorescent substance emits light by recombination energy of holes injected from an anode and electrons injected from a cathode by applying an electric field. Eastman Kodak's C.I. W. Organic materials have been constructed since Tang et al. Reported low-voltage driven organic EL devices using stacked devices (CW Tang, SA Vanslyke, Applied Physics Letters, 51, 913, 1987, etc.) Research on organic EL elements as materials has been actively conducted. Tang et al. Use tris (8-quinolinolato) aluminum for the light emitting layer and a triphenyldiamine derivative for the hole transporting layer. The advantages of the stacked structure are that it increases the efficiency of hole injection into the light-emitting layer, blocks the electrons injected from the cathode, increases the generation efficiency of excitons generated by recombination, and generates in the light-emitting layer For example, confining excitons. As in this example, the element structure of the organic EL element includes a hole transport (injection) layer, a two-layer type of an electron transport light-emitting layer, or a hole transport (injection) layer, a light-emitting layer, and an electron transport (injection) layer. A three-layer type is well known. In such a stacked structure element, the element structure and the formation method are devised in order to increase the recombination efficiency of injected holes and electrons.

Patent Documents 1 and 2 disclose an organic EL element having a reduced driving voltage in which a charge generation layer made of a compound having a hexaazatriphenylene (HAT) structure is provided. On the other hand, Patent Document 3 discloses an aromatic amine derivative having a specific substituent containing a thiophene structure.
However, from the viewpoint of light emission efficiency and device lifetime, development of an organic EL device having better performance is desired.

Japanese Patent No. 4673279 Japanese Patent No. 4790565 WO2008 / 023759

Further, as a result of investigation by the present inventor, when the organic EL element is provided with a charge generation layer made of a compound having the above-described HAT structure, the luminance of the organic EL element is rapidly changed at the initial stage of driving. It was found that a problem arises.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an organic electroluminescence device having high luminous efficiency, excellent device performance stability, and long device life.

［式中、Ｌ₁は、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。
Ａｒ₁〜Ａｒ₄のうち少なくとも１つは下記一般式（２）で表される基である。

｛式中、Ｒ₁は、置換もしくは無置換の環形成炭素数６〜５０のアリール基、置換もしくは無置換の炭素数１〜５０のアルキル基、ハロゲン原子又はシアノ基である。
ａは１〜３の整数である。
Ｌ₂は、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。｝
一般式（１）において、Ａｒ₁〜Ａｒ₄のうち一般式（２）で表されるもの以外は、それぞれ独立に、置換もしくは無置換の環形成炭素数６〜５０のアリール基である。］
［２］前記一般式（２）で表される基が、下記一般式（３）で表される［１］に記載の有機エレクトロルミネッセンス素子。

｛式中、Ｒ₁は置換もしくは無置換の環形成炭素数６〜５０のアリール基又は置換もしくは無置換の炭素数１〜５０のアルキル基である。
Ｌ₂は、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。｝
［３］前記アクセプター層が、下記一般式（７）で表されるアクセプター材料を含有する［１］又は［２］に記載の有機エレクトロルミネッセンス素子。

（式中、Ｒ¹¹〜Ｒ¹⁶は、それぞれ独立に、シアノ基、ニトロ基、スルホニル基、カルボニル基、トリフルオロメチル基、又はハロゲン原子である。）
［４］前記一般式（１）においてＡｒ₁が前記一般式（２）で表される基である［１］〜［３］のいずれかに記載の有機エレクトロルミネッセンス素子。
［５］前記一般式（１）においてＬ₁がビフェニリレン基、テルフェニリレン基又はフルオレニレン基である［１］〜［４］のいずれかに記載の有機エレクトロルミネッセンス素子。
［６］前記一般式（２）においてＬ₂がフェニレン基、ビフェニリレン基又はフルオレニレン基である［１］〜［５］のいずれかに記載の有機エレクトロルミネッセンス素子。
［７］前記一般式（２）においてＲ₁がフェニル基、ナフチル基又はフェナントレニル基である［１］〜［６］のいずれかに記載の有機エレクトロルミネッセンス素子。
［８］陽極及び陰極間に発光層を有する有機エレクトロルミネッセンス素子であって、陽極と発光層の間に第一正孔注入層、アクセプター層及び第二正孔注入層を順に備え、第一正孔注入層が下記一般式（４）〜（６）のいずれかで表される芳香族アミン誘導体を含有する有機エレクトロルミネッセンス素子。

［式中、Ｌ₅〜Ｌ₁₂は、それぞれ独立に、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。
Ａｒ₅〜Ａｒ₉のうち少なくとも１つは下記一般式（２）で表される基である。
Ａｒ₁₀〜Ａｒ₁₅のうち少なくとも１つは下記一般式（２）で表される基である。
Ａｒ₁₆〜Ａｒ₂₁のうち少なくとも１つは下記一般式（２）で表される基である。

｛式中、Ｒ₁は、置換もしくは無置換の環形成炭素数６〜５０のアリール基、置換もしくは無置換の炭素数１〜５０のアルキル基、ハロゲン原子又はシアノ基である。
ａは１〜３の整数である。
Ｌ₂は、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。｝
一般式（４）〜（６）において、Ａｒ₅〜Ａｒ₂₁のうち一般式（２）で表されるもの以外は、それぞれ独立に、置換もしくは無置換の環形成炭素数６〜５０のアリール基である。］
［９］前記一般式（２）で表される基が、下記一般式（３）で表される［８］に記載の有機エレクトロルミネッセンス素子。

｛式中、Ｒ₁は、置換もしくは無置換の環形成炭素数６〜５０のアリール基又は置換もしくは無置換の炭素数１〜５０のアルキル基である。
Ｌ₂は、置換もしくは無置換の環形成炭素数６〜５０のアリーレン基を表す。｝
［１０］前記アクセプター層が、下記一般式（７）で表されるアクセプター材料を含有する［８］又は［９］に記載の有機エレクトロルミネッセンス素子。

（式中、Ｒ¹¹〜Ｒ¹⁶は、それぞれ独立に、シアノ基、ニトロ基、スルホニル基、カルボニル基、トリフルオロメチル基、又はハロゲン原子である。）
［１１］発光層にアリールアミン化合物を含有する［１］〜［１０］のいずれかに記載の有機エレクトロルミネッセンス素子。
［１２］青色系発光する［１］〜［１１］のいずれかに記載の有機エレクトロルミネッセンス素子。 As a result of intensive studies to achieve the above object, the present inventor includes an aromatic amine derivative having a specific substituent represented by the following general formula (1) in the first hole injection layer, Furthermore, it discovered that said subject was solved by the organic EL element provided with the acceptor layer and the 2nd hole injection layer, and came to complete this invention.
That is, the present invention provides the following inventions.
[1] An organic electroluminescence device having a light emitting layer between an anode and a cathode, comprising a first hole injection layer, an acceptor layer, and a second hole injection layer in that order between the anode and the light emitting layer. An organic electroluminescence device wherein the hole injection layer contains an aromatic amine derivative represented by the following general formula (1).

[Wherein, L ₁ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{1 to} Ar ₄ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In General Formula (1), those other than those represented by General Formula (2) among Ar _{1 to} Ar ₄ are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. ]
[2] The organic electroluminescence device according to [1], wherein the group represented by the general formula (2) is represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
[3] The organic electroluminescence device according to [1] or [2], wherein the acceptor layer contains an acceptor material represented by the following general formula (7).

(In the formula, R ^{11 to} R ¹⁶ are each independently a cyano group, a nitro group, a sulfonyl group, a carbonyl group, a trifluoromethyl group, or a halogen atom.)
[4] The organic electroluminescence device according to any one of [1] to [3], wherein Ar ₁ in the general formula (1) is a group represented by the general formula (2).
[5] The organic electroluminescence device according to any one of [1] to [4], wherein L ₁ in the general formula (1) is a biphenylylene group, a terphenylylene group, or a fluorenylene group.
[6] The organic electroluminescence device according to any one of [1] to [5], wherein L ₂ in the general formula (2) is a phenylene group, a biphenylylene group, or a fluorenylene group.
[7] The organic electroluminescence device according to any one of [1] to [6], wherein R ₁ in the general formula (2) is a phenyl group, a naphthyl group, or a phenanthrenyl group.
[8] An organic electroluminescence device having a light emitting layer between an anode and a cathode, comprising a first hole injection layer, an acceptor layer, and a second hole injection layer in that order between the anode and the light emitting layer. The organic electroluminescent element in which a hole injection layer contains the aromatic amine derivative represented by either of following General formula (4)-(6).

[Wherein, L _{5 to} L ₁₂ each independently represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{5 to} Ar ₉ is a group represented by the following general formula (2).
At least one of Ar _{10 to} Ar ₁₅ is a group represented by the following general formula (2).
At least one of Ar _{16 to} Ar ₂₁ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In general formulas (4) to (6), except for those represented by general formula (2) among Ar _{5 to} Ar ₂₁ , each independently or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. It is. ]
[9] The organic electroluminescence device according to [8], wherein the group represented by the general formula (2) is represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
[10] The organic electroluminescence device according to [8] or [9], wherein the acceptor layer contains an acceptor material represented by the following general formula (7).

(In the formula, R ^{11 to} R ¹⁶ are each independently a cyano group, a nitro group, a sulfonyl group, a carbonyl group, a trifluoromethyl group, or a halogen atom.)
[11] The organic electroluminescence device according to any one of [1] to [10], wherein the light emitting layer contains an arylamine compound.
[12] The organic electroluminescence device according to any one of [1] to [11], which emits blue light.

  The organic EL device of the present invention has high luminous efficiency, excellent device performance stability, and long device life.

It is a schematic sectional drawing which shows an example of the organic EL element of this invention. It is a graph which contrasts the drive time and brightness | luminance (relative value) of the organic EL element obtained in Example 1 and Comparative Examples 1-2.

  The organic electroluminescence device of the present invention has a light emitting layer between an anode and a cathode, and includes a first hole injection layer, an acceptor layer, and a second hole injection layer in this order between the anode and the light emitting layer. The hole injection layer contains an aromatic amine derivative represented by the following general formula (1). FIG. 1 shows an example of the organic EL element of the present invention.

[Wherein, L ₁ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{1 to} Ar ₄ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In General Formula (1), those other than those represented by General Formula (2) among Ar _{1 to} Ar ₄ are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. ]

  In the aromatic amine derivative represented by the general formula (1), the group represented by the general formula (2) is preferably represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }

In the above-mentioned aromatic amine derivative, Ar ₁ in the general formula (1) is preferably a group represented by the general formula (2).
In the above-mentioned aromatic amine derivative, Ar ₁ and Ar ₂ in the general formula (1) are preferably each independently a group represented by the general formula (2).
In the aromatic amine derivative, Ar ₁ and Ar ₃ in the general formula (1) are preferably groups independently represented by the general formula (2).
The aromatic amine derivative preferably has a structure in which at least three of Ar _{1 to} Ar ₄ are different from each other in the general formula (1).
In the above-mentioned aromatic amine derivative, three of Ar _{1 to} Ar ₄ in the general formula (1) have the same structure, and the remaining one preferably has a different structure.
In the general formula (1), the aromatic amine derivative other than the group represented by the general formula (2) among Ar _{1 to} Ar ₄ is independently a phenyl group, a biphenylyl group, a terphenylyl group, or a fluorenyl group. And preferred.
In the above-mentioned aromatic amine derivative, L ₁ in the general formula (1) is preferably a biphenylylene group, a terphenylylene group or a fluorenylene group.
In the aromatic amine derivative, L ₂ in the general formula (2) is preferably a phenylene group, a biphenylylene group or a fluorenylene group.
In the above-mentioned aromatic amine derivative, R ₁ in the general formula (2) is preferably a phenyl group, a naphthyl group or a phenanthrenyl group.
In the general formula (1), the aromatic amine derivative is independently a phenyl group, a biphenylyl group, a terphenylyl group, or a fluorenyl group, except for the group represented by the general formula (2) among Ar _{1 to} Ar ₄ . , L ₁ is a biphenylylene group, a terphenylylene group, or a fluorenylene group, and in the general formula (2), L ₂ is preferably a phenylene group, a biphenylylene group, or a fluorenylene group.

  Furthermore, the organic electroluminescent element of the present invention uses an aromatic amine derivative represented by any one of the following general formulas (4) to (6) instead of the one represented by the general formula (1). It may be a thing.

[Wherein, L _{5 to} L ₁₂ each independently represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{5 to} Ar ₉ is a group represented by the following general formula (2).
At least one of Ar _{10 to} Ar ₁₅ is a group represented by the following general formula (2).
At least one of Ar _{16 to} Ar ₂₁ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In general formulas (4) to (6), except for those represented by general formula (2) among Ar _{5 to} Ar ₂₁ , each independently or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. It is. ]

  In the aromatic amine derivatives represented by the general formulas (4) to (6), the group represented by the general formula (2) is preferably represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }

In the general formula (4), at least one of the aromatic amine derivatives is preferably a group represented by the general formula (2) among Ar _{5 to} Ar ₉ .
In the aromatic amine derivative, Ar ₅ in the general formula (4) is preferably a group represented by the general formula (2).
In the aromatic amine derivative, Ar ₆ and Ar ₈ in the general formula (4) are preferably groups independently represented by the general formula (2).
The aromatic amine derivative is preferably a group represented by the general formula (2) in which at least one of Ar _{10 to} Ar ₁₅ in the general formula (5).
In the above-mentioned aromatic amine derivative, Ar ₁₀ and Ar ₁₅ in the general formula (5) are preferably each independently a group represented by the general formula (2).
In the aromatic amine derivative, Ar ₁₁ and Ar ₁₃ in the general formula (5) are preferably groups independently represented by the general formula (2).
The aromatic amine derivative is preferably a group represented by the general formula (2) in which at least one of Ar _{16 to} Ar ₂₁ in the general formula (6).
In the aromatic amine derivative, Ar ₁₆ , Ar _18, and Ar ₂₀ in the general formula (6) are preferably groups independently represented by the general formula (2).
In the general formulas (4) to (6), the aromatic amine derivative is independently a phenyl group, a biphenylyl group, a terphenylyl group, or a group other than the group represented by the general formula (2) among Ar _{5 to} Ar _21. A fluorenyl group is preferred.
In the above-mentioned aromatic amine derivatives, L _{5 to} L ₁₂ in the general formulas (4) to (6) are preferably each independently a phenylene group, a biphenylylene group, a terphenylylene group, or a fluorenylene group.
In the aromatic amine derivative, L ₂ in the general formula (2) is preferably a phenylene group, a biphenylylene group or a fluorenylene group.
In the above-mentioned aromatic amine derivative, R ₁ in the general formula (2) is preferably a phenyl group, a naphthyl group or a phenanthrenyl group.
In the general formulas (4) to (6), the aromatic amine derivative is independently a phenyl group, a biphenylyl group, a terphenylyl group or a group other than the one represented by the general formula (2) among Ar _{5 to} Ar _21. It is preferably a fluorenyl group, L _{5 to} L ₁₂ are a phenylene group, a biphenylylene group, a terphenylylene group or a fluorenylene group, and L ₂ in the general formula (2) is preferably a phenylene group, a biphenylylene group or a fluorenylene group.

Ar _{1 to} Ar ₂₁ in the general formulas (1) and (4) to (6) and R ₁ in the general formulas (2) and (3) are substituted or unsubstituted aryl groups having 6 to 50 ring carbon atoms. For example, phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group P-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m- Ruphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butylphenyl group, p- (2-phenylpropyl) phenyl group 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylyl group, 4 ″ -t-butyl-p-terphenyl-4-yl Group, fluoranthenyl group, fluorenyl group and the like.
Among these, a phenyl group, a naphthyl group, a biphenylyl group, a terphenylyl group, and a fluorenyl group are preferable.
Since the thiophene compound has high reactivity at the 2-position and 5-position, it is desirable to protect this substitution position. Known documents include Macromol. Rapid Commun., 2001, 22, 266-270, and it is reported that polymerization is progressed electrically unstable. As the substituent, an alkyl group or an aryl group is desirable, but an aryl group is preferable in view of the stability of the compound, and an unsubstituted aryl group is more preferable.

Formula (1) and (4) ~ L ₁ and in (6) L ₅ ~L _12, and the general formula (2) and (3) in a L ₂ substituted or unsubstituted ring carbon of 5 to 50 Examples of the arylene group include those having the above aryl group as a divalent group.

Examples of the substituted or unsubstituted alkyl group having 1 to 50 carbon atoms which is R ₁ in the general formulas (2) and (3) include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s- Butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1,2,3-tribromo Lopyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1 , 2,3-triiodopropyl group, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano -T-butyl group, 1,2,3-tricyanopropyl group, trifluoromethyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-methylcyclohexyl group, 1-adamantyl group, 2-adamantyl group , 1-norbornyl group, 2-norbornyl group and the like. Preferably, it is a saturated chain, branched or cyclic alkyl group composed of hydrocarbon, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group. T-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-methylcyclohexyl group, 1-adamantyl group, A 2-adamantyl group, a 1-norbornyl group, a 2-norbornyl group and the like can be mentioned.

Examples of the halogen atom as R ₁ in the general formulas (2) and (3) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The substituent for Ar _{1 to} Ar ₂₁ is preferably an aryl group having 6 to 50 ring carbon atoms, an alkyl group having 1 to 50 carbon atoms, a halogen atom or a cyano group, and specific examples thereof are the same as described above.

In General formula (2), a is an integer of 1-3. When a is 2 or more, a plurality of R ₁ may be bonded to each other to form a saturated or unsaturated 5-membered or 6-membered cyclic structure.
Examples of the 5-membered or 6-membered cyclic structure formed by bonding a plurality of R ₁ to each other include cycloalkanes having 4 to 12 carbon atoms such as cyclopentane, cyclohexane, adamantane, norbornane, cyclopentene, and cyclohexene. C6-C12 cycloalkadiene, such as C4-C12 cycloalkene, cyclopentadiene, cyclohexadiene, etc. are mentioned.

  Specific examples of the aromatic amine derivatives represented by the general formulas (1) and (4) to (6) are shown below, but are not limited to these exemplified compounds.

  The organic EL device of the present invention comprises a first hole injection layer, an acceptor layer, and a second hole injection layer in this order between the anode and the light emitting layer, and the first hole injection layer is the sole aromatic amine derivative. Or it contains as a component of a mixture.

  Fluorescent dopants that may be contained in the light emitting layer include amine compounds, aromatic compounds, chelate complexes such as tris (8-quinolinolato) aluminum complexes, coumarin derivatives, tetraphenylbutadiene derivatives, bisstyrylarylene derivatives, oxadi It is preferable that the compound is selected from azole derivatives according to the required emission color, and in particular, an arylamine compound and an aryldiamine compound are mentioned. Among them, a styrylamine compound, a styryldiamine compound, an aromatic amine compound, Aromatic diamine compounds are more preferred. Further, condensed polycyclic aromatic compounds (excluding amine compounds) are more preferable. These fluorescent dopants may be used alone or in combination.

  Condensed polycyclic aromatic compounds (excluding amine compounds) include naphthalene, anthracene, phenanthrene, pyrene, coronene, biphenyl, terphenyl, pyrrole, furan, thiophene, benzothiophene, oxadiazole, indole, carbazole, pyridine, benzo Preferred are condensed polycyclic aromatic compounds such as quinoline, fluoranthene, benzofluoranthene, acenaphthofluoranthene, stilbene, perylene, chrysene, picene, triphenylene, rubicene, benzoanthracene, and derivatives thereof.

  As the organic electroluminescent element of the present invention, those emitting blue light are preferable.

Hereinafter, the element structure of the organic EL element of the present invention will be described.
(1) Structure of organic EL element As a typical element structure of the organic EL element of the present invention,
(1) Anode / first hole injection layer / acceptor layer / second hole injection layer / light emitting layer / cathode (2) Anode / first hole injection layer / acceptor layer / second hole injection layer / light emitting layer / Electron injection layer / cathode (3) anode / first hole injection layer / acceptor layer / second hole injection layer / organic semiconductor layer / light emitting layer / cathode (4) anode / first hole injection layer / acceptor layer / Second hole injection layer / organic semiconductor layer / electron barrier layer / light emitting layer / cathode (5) anode / first hole injection layer / acceptor layer / second hole injection layer / organic semiconductor layer / light emitting layer / attachment Improvement layer / cathode (6) Anode / first hole injection layer / acceptor layer / second hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode (7) Anode / first hole injection layer / Acceptor layer / second hole injection layer / light emitting layer / electron transport layer / electron injection layer / cathode (8) anode / first hole injection layer / active layer Scepter layer / second hole injection layer / insulating layer / light emitting layer / insulating layer / cathode (9) anode / first hole injection layer / acceptor layer / second hole injection layer / inorganic semiconductor layer / insulating layer / light emission Layer / insulating layer / cathode (10) anode / first hole injection layer / acceptor layer / second hole injection layer / organic semiconductor layer / insulating layer / light emitting layer / insulating layer / cathode (11) anode / first positive Hole injection layer / acceptor layer / second hole injection layer / insulating layer / hole transport layer / light emitting layer / insulating layer / cathode (12) anode / first hole injection layer / acceptor layer / second hole injection layer / Insulating layer / hole transport layer / light emitting layer / electron injection layer / cathode (13) anode / first hole injection layer / acceptor layer / second hole injection layer / hole transport layer / light emitting layer / electron transport layer / The structure of a cathode etc. can be mentioned.
Of these, the structure of (13) is preferably used, but is not limited thereto.

(2) Translucent board | substrate The organic EL element of this invention is produced on a translucent board | substrate. Here, the translucent substrate is a substrate that supports the organic EL element, and is preferably a smooth substrate having a light transmittance in the visible region of 400 to 700 nm of 50% or more.
Specifically, a glass plate, a polymer plate, etc. are mentioned. Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

(3) Anode The anode of the organic EL device of the present invention has a function of injecting holes into the first hole injection layer, and it is effective to have a work function of 4.5 eV or more. Specific examples of the anode material used in the present invention include indium tin oxide alloy (ITO), tin oxide (NESA), indium-zinc oxide (IZO), gold, silver, platinum, copper and the like.
The anode can be produced by forming a thin film from these electrode materials by a method such as vapor deposition or sputtering.
Thus, when light emission from the light emitting layer is taken out from the anode, it is preferable that the transmittance for light emission of the anode is larger than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. Although the film thickness of the anode depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

(4) First hole injection layer The first hole injection layer is a layer that assists hole injection into the acceptor layer, and preferably has a high hole mobility and a small ionization energy of usually 5.6 eV or less. . As such a hole injection layer, a material containing the aromatic amine derivative that transports holes to the light emitting layer with lower electric field strength is preferable, and the hole mobility is, for example, 10 ⁴ to 10 ⁶ V / When an electric field of cm is applied, it is preferably at least 10 ⁻⁴ cm ² / V · sec.
The above-mentioned aromatic amine derivative can be used alone for the first hole injection layer, but may be used by mixing with other materials.
The hole injecting material mixed with the aromatic amine derivative to form the first hole injecting layer is not particularly limited as long as it has the above-mentioned preferable properties. Any material commonly used as a transport material or a known material used for a hole injection / transport layer of an organic EL element can be selected and used. In the present invention, a material that has a hole injection capability and can be used in the hole transport zone is called a hole injection material.
The first hole injection layer contains the aromatic amine derivative, and the content of the aromatic amine derivative in the first hole injection layer is preferably 30 to 100 mol%.

  Specific examples of the hole injection material include triazole derivatives (see US Pat. No. 3,112,197), oxadiazole derivatives (see US Pat. No. 3,189,447), imidazole derivatives (special No. 37-16096), polyarylalkane derivatives (US Pat. No. 3,615,402, US Pat. No. 3,820,989, US Pat. No. 3,542,544) 45-555, 51-10983, JP-A-51-93224, 55-17105, 56-4148, 55-108667, 55-156953, 56-36656), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,180,729, US Pat. No. 4,278,7). No. 6, JP-A-55-88064, JP-A-55-88065, JP-A-49-105537, JP-A-55-51086, JP-A-56-80051, JP-A-56-88141, 57-45545, 54-11126, 55-74546, etc.), phenylenediamine derivatives (US Pat. No. 3,615,404, JP 51-10105, 46- No. 3712, No. 47-25336, Japanese Patent Laid-Open No. 54-1119925, etc.), arylamine derivatives (US Pat. No. 3,567,450, No. 3,240,597, No. 3,658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, JP-B-49-35702, JP-A-39-27577, JP-A-55-144250, JP-A-56-119132, JP-A-56-22437, West German Patent No. 1,110,518, etc. Reference), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501, etc.), oxazole derivatives (disclosed in US Pat. No. 3,257,203 etc.), styrylanthracene derivatives (JP No. 56-46234, etc.), fluorenone derivatives (see JP 54-110837 A, etc.), hydrazone derivatives (US Pat. No. 3,717,462, JP 54-59143 A). 55-52063, 55-52064, 55-46760, 57-11350, 57-1487. No. 9 and JP-A-2-315991), stilbene derivatives (JP-A Nos. 61-210363, 61-228451, 61-14642, 61-72255, etc.) 62-47646, 62-36674, 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, 60 -175052, etc.), silazane derivatives (US Pat. No. 4,950,950), polysilanes (JP-A-2-204996), aniline copolymers (JP-A-2-282263) Etc.

As the hole injecting material, those described above can be used. Porphyrin compounds (disclosed in JP-A-63-295695), aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 55-79450, 55-144250, 56-119132, 61-295558 No. 61-98353, No. 63-295695, etc.), in particular, an aromatic tertiary amine compound is preferably used.
In addition, as a hole injection material, for example, 4,4′-bis (N- (1- (1)) having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule. Naphthyl) -N-phenylamino) biphenyl (hereinafter abbreviated as NPD) and 4,4 ′, 4 in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type "-Tris (N- (3-methylphenyl) -N-phenylamino) triphenylamine (hereinafter abbreviated as MTDATA) and the like.

  Further, as the hole injection material, in addition to this, those represented by the following general formula (7) described in US Publication No. 2004/0113547, and the following general formula (8) disclosed in Japanese Patent No. 3571977 are used. Acceptor materials such as those represented can also be used.

（式中、Ｒ¹¹〜Ｒ¹⁶は、それぞれ独立に、シアノ基、ニトロ基、スルホニル基、カルボニル基、トリフルオロメチル基、又はハロゲン原子である。）

(In the formula, R ^{11 to} R ¹⁶ are each independently a cyano group, a nitro group, a sulfonyl group, a carbonyl group, a trifluoromethyl group, or a halogen atom.)

（式中、Ｒ²¹〜Ｒ²⁶は、それぞれ置換又は無置換のアルキル基、置換又は無置換のアリール基、置換又は無置換のアラルキル基、置換又は無置換の複素環基のいずれかを示す。但し、Ｒ²¹〜Ｒ²⁶は同じでも異なっていてもよい。また、Ｒ²¹とＲ²²、Ｒ²³とＲ²⁴、Ｒ²⁵とＲ²⁶、Ｒ²¹とＲ²⁶、Ｒ²²とＲ²³、Ｒ²⁴とＲ²⁵が縮合環を形成していてもよい。）

(In the formula, R ^{21 to} R ²⁶ each represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted heterocyclic group. R ^{21 to} R ²⁶ may be the same or different, and R ²¹ and R ²² , R ²³ and R ²⁴ , R ²⁵ and R ²⁶ , R ²¹ and R ²⁶ , R ²² and R ²³ , R ²⁴ And R ²⁵ may form a condensed ring.)

As typified by the above materials, acceptor materials can also be used as the hole injection material.
Further, inorganic compounds such as p-type Si and p-type SiC can be used as the hole injection material in addition to the above-described aromatic dimethylidin-based compounds shown as the material of the light emitting layer.

  The first hole injection layer can be formed by thinning the above-described material by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although there is no restriction | limiting in particular in the film thickness of a 1st positive hole injection layer, Usually, they are 5 nm-5 micrometers.

(5) Acceptor layer As the material for forming the acceptor layer, the above-described acceptor materials are preferably used.
The formation method and film thickness of the acceptor layer are the same as those of the first hole injection layer.

(6) Second hole injection layer The details of the second hole injection layer are the same as those of the first hole injection layer.
Further, an organic semiconductor layer may be provided as a layer for assisting hole injection into the light emitting layer, and those having a conductivity of 10 ⁻¹⁰ S / cm or more are suitable. As a material for such an organic semiconductor layer, a conductive oligomer such as a thiophene-containing oligomer, an arylamine oligomer disclosed in JP-A-8-193191, a conductive dendrimer such as an arylamine dendrimer, or the like is used. Can do.

(7) Light emitting layer The light emitting layer of the organic EL device has the following functions (1) to (3).
(1) Injection function; function that allows holes to be injected from the anode or hole injection layer when an electric field is applied, and electron can be injected from the cathode or electron injection layer (2) transport function; injected charge (electrons (3) Light-emitting function; a function to provide a recombination field between electrons and holes and connect it to light emission However, the ease of hole injection and electron injection There may be a difference in ease, and the transport ability represented by the mobility of holes and electrons may be large or small, but it is preferable to move one of the charges.
As a method for forming the light emitting layer, for example, a known method such as an evaporation method, a spin coating method, or an LB method can be applied. The light emitting layer is particularly preferably a molecular deposited film. Here, the molecular deposition film is a thin film formed by deposition from a material compound in a gas phase state or a film formed by solidification from a material compound in a solution state or a liquid phase state. Can be classified from a thin film (accumulated film) formed by the LB method according to a difference in an agglomerated structure and a higher-order structure and a functional difference resulting therefrom.
Further, as disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, and then this is thinned by a spin coating method or the like. In addition, a light emitting layer can be formed.
When the aromatic amine derivative is used in the light emitting layer, other known light emitting materials other than the light emitting material composed of the aromatic amine derivative may be contained in the light emitting layer as desired, as long as the object of the present invention is not impaired. Alternatively, a light emitting layer containing another known light emitting material may be laminated on a light emitting layer containing a light emitting material made of an aromatic amine derivative.

  The light emitting material used for the light emitting layer is mainly an organic compound, and examples of the doping material that can be used include anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, Naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinylanthracene , Diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelating oxinoid compound, quinaclide Although rubrene and fluorescent dyes, and the like, but is not limited thereto.

As the host material used for the light emitting layer, compounds represented by the following (i) to (iv) are preferable.
Asymmetric anthracene represented by the following general formula (i).

(In the formula, Ar is a substituted or unsubstituted condensed aromatic group having 10 to 50 ring carbon atoms.
Ar ′ is a substituted or unsubstituted aromatic group having 6 to 50 ring carbon atoms.
X is a substituted or unsubstituted aromatic group having 6 to 50 ring carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 ring atoms, a substituted or unsubstituted carbon group having 1 to 50 carbon atoms. An alkyl group, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 ring carbon atoms, substituted or An unsubstituted arylthio group having 5 to 50 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxy group.
a, b, and c are each an integer of 0-4.
n is an integer of 1 to 3. When n is 2 or more, the numbers in [] may be the same or different. )

  An asymmetric monoanthracene derivative represented by the following general formula (ii).

(In the formula, Ar ¹ and Ar ² are each independently a substituted or unsubstituted aromatic ring group having 6 to 50 ring carbon atoms, and m and n are each an integer of 1 to 4. However, , M = n = 1, and Ar ¹ and Ar ² are symmetric with respect to the benzene ring, Ar ¹ and Ar ² are not the same, and m or n is an integer of 2 to 4 Where m and n are different integers.
R ^{1 to} R ¹⁰ are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 ring atoms. Substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, substituted or unsubstituted aralkyl having 6 to 50 carbon atoms A substituted or unsubstituted aryloxy group having 5 to 50 ring atoms, a substituted or unsubstituted arylthio group having 5 to 50 ring atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, Substituted or unsubstituted silyl group, carboxyl group, halogen atom, cyano group, nitro group, hydroxy group. )

  An asymmetric anthracene derivative represented by the following general formula (iii):

(In the formula, A ¹ and A ² are each independently a substituted or unsubstituted condensed aromatic ring group having 10 to 20 ring carbon atoms.
Ar ¹ and Ar ² are each independently a hydrogen atom or a substituted or unsubstituted aromatic ring group having 6 to 50 ring carbon atoms.
R ^{1 to} R ¹⁰ are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 ring atoms. Substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, substituted or unsubstituted aralkyl having 6 to 50 carbon atoms A group, a substituted or unsubstituted aryloxy group having 5 to 50 ring carbon atoms, a substituted or unsubstituted arylthio group having 5 to 50 ring carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, A substituted or unsubstituted silyl group, carboxyl group, halogen atom, cyano group, nitro group or hydroxy group.
Ar ¹ , Ar ² , R ^9, and R ¹⁰ may be plural, and adjacent ones may form a saturated or unsaturated cyclic structure.
However, in the general formula (iii), a group that is symmetrical with respect to the XY axis shown on the anthracene is not bonded to the 9th and 10th positions of the central anthracene. )

  A compound having an anthracene center skeleton represented by the following general formula (iv).

(In formula (iv), A ₁ and A ₂ are each independently a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms. The aromatic ring is one or more. It may be substituted with a substituent.
The substituent is a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted group. Or an unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear atoms, and a substituted or unsubstituted nuclear atom. It is selected from an arylthio group having 5 to 50 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group.
When the aromatic ring is substituted with two or more substituents, the substituents may be the same or different, and adjacent substituents are bonded to each other to form a saturated or unsaturated cyclic structure. It may be formed.
R _{1 to} R ₈ are each independently a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, a substituted or unsubstituted group. An alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, and a substituted or unsubstituted aralkyl having 6 to 50 carbon atoms. Group, substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or It is selected from unsubstituted silyl group, carboxyl group, halogen atom, cyano group, nitro group and hydroxyl group. )

A compound having a structure represented by the following general formula (v), wherein A ₁ and A ₂ are different groups in the general formula (iv).

(In the formula (v), A ₁ and A _2, R ₁ ~R ₈ each independently is the same as the general formula (iv).
However, a symmetric group with respect to the XY axis shown on the anthracene is not bonded to the 9th and 10th positions of the central anthracene. )

Among the above host materials, anthracene derivatives are preferable, monoanthracene derivatives are more preferable, and asymmetric anthracene is particularly preferable.
A host suitable for phosphorescence emission comprising a compound containing a carbazole ring is a compound having a function of causing the phosphorescence emission compound to emit light as a result of energy transfer from the excited state to the phosphorescence emission compound. The host compound is not particularly limited as long as it is a compound capable of transferring exciton energy to the phosphorescent compound, and can be appropriately selected according to the purpose. You may have arbitrary heterocyclic rings other than a carbazole ring.

Specific examples of such host compounds include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcones. Derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone Derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidene methane derivatives, distyryl pyrazine derivatives, naphthalene pens Heterocyclic tetracarboxylic anhydrides such as lene, metal complexes of phthalocyanine derivatives, 8-quinolinol derivatives, metal phthalocyanines, metal complexes having benzoxazole and benzothiazole ligands, various metal complexes polysilane compounds, poly Examples include (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, polymer compounds such as polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, and polyfluorene derivatives. A host compound may be used independently and may use 2 or more types together.
Specific examples include the following compounds.

A phosphorescent dopant is a compound that can emit light from triplet excitons. Although it is not particularly limited as long as it emits light from triplet excitons, it is preferably a metal complex containing at least one metal selected from the group consisting of Ir, Ru, Pd, Pt, Os and Re, and is preferably a porphyrin metal complex or ortho Metalated metal complexes are preferred. The porphyrin metal complex is preferably a porphyrin platinum complex. Phosphorescent compounds may be used alone or in combination of two or more.
There are various ligands that form orthometalated metal complexes. Preferred ligands include 2-phenylpyridine derivatives, 7,8-benzoquinoline derivatives, and 2- (2-thienyl) pyridine derivatives. , 2- (1-naphthyl) pyridine derivatives, 2-phenylquinoline derivatives, and the like. These derivatives may have a substituent as necessary. In particular, a fluorinated compound or a compound having a trifluoromethyl group introduced is preferable as a blue dopant. Furthermore, you may have ligands other than the said ligands, such as an acetylacetonate and picric acid, as an auxiliary ligand.
There is no restriction | limiting in particular as content in the light emitting layer of a phosphorescence-emitting dopant, Although it can select suitably according to the objective, For example, it is 0.1-70 mass%, and 1-30 mass% is preferable. When the content of the phosphorescent compound is less than 0.1% by mass, the light emission is weak and the effect of the content is not sufficiently exhibited. When the content exceeds 70% by mass, a phenomenon called concentration quenching becomes prominent, and the element Performance decreases.
The light emitting layer may contain a hole transport material, an electron transport material, and a polymer binder as necessary.
Furthermore, the thickness of the light emitting layer is preferably 5 to 50 nm, more preferably 7 to 50 nm, and most preferably 10 to 50 nm. If the thickness is less than 5 nm, it is difficult to form a light emitting layer, and it may be difficult to adjust the chromaticity. If the thickness exceeds 50 nm, the driving voltage may increase.

(8) Electron Injection / Transport Layer Next, the electron injection layer / transport layer is a layer that assists the injection of electrons into the light emitting layer and transports it to the light emitting region, and has a high electron mobility. Of these electron injection layers, the layer is made of a material that particularly adheres well to the cathode.
In addition, since light emitted from an organic EL element is reflected by an electrode (in this case, a cathode), it is known that light emitted directly from the anode interferes with light emitted via reflection by the electrode. . In order to efficiently use this interference effect, the electron transport layer is appropriately selected with a film thickness of several nanometers to several micrometers, but particularly when the film thickness is large, 10 ⁴ to 10 ⁶ V / It is preferable that the electron mobility is at least 10 ⁻⁵ cm ² / Vs or more when an electric field of cm is applied.
As a material used for the electron injection layer, 8-hydroxyquinoline or a metal complex of its derivative or an oxadiazole derivative is preferable. As a specific example of the above-mentioned metal complex of 8-hydroxyquinoline or a derivative thereof, a metal chelate oxinoid compound containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline), for example, tris (8-quinolinol) aluminum is injected. It can be used as a material.

  On the other hand, examples of the oxadiazole derivative include electron transfer compounds represented by the following general formula.

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁵ , Ar ⁶ , Ar ⁹ each represents a substituted or unsubstituted aryl group, and may be the same or different from each other. Ar ⁴ , Ar ⁷ and Ar ⁸ represent a substituted or unsubstituted arylene group, which may be the same or different.
Here, examples of the aryl group include a phenyl group, a biphenylyl group, an anthryl group, a perylenyl group, and a pyrenyl group. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylylene group, an anthrylene group, a peryleneylene group, and a pyrenylene group. Moreover, as a substituent, a C1-C10 alkyl group, a C1-C10 alkoxy group, a cyano group, etc. are mentioned. This electron transfer compound is preferably a thin film-forming compound.

  Specific examples of the electron transfer compound include the following.

  Furthermore, materials represented by the following general formulas (A) to (F) can also be used as materials used for the electron injection layer and the electron transport layer.

(In the general formulas (A) and (B), A ^{1 to} A ³ are each independently a nitrogen atom or a carbon atom.
Ar ¹ is a substituted or unsubstituted aryl group having 6 to 60 nuclear carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 60 nuclear carbon atoms in the formula (A). Ar ¹ is a group in which Ar ¹ in formula (A) is a divalent arylene group, and Ar ² is a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, a substituted or unsubstituted nucleus. They are a C3-C60 heteroaryl group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, or these bivalent groups. However, any ^one of Ar ¹ and Ar ² is a substituted or unsubstituted fused ring group having 10 to 60 nuclear carbon atoms, a substituted or unsubstituted monoheterofused ring group having 3 to 60 nuclear carbon atoms, or these It is a divalent group.
L ¹ , L ² and L are each independently a single bond, a substituted or unsubstituted arylene group having 6 to 60 nuclear carbon atoms, a substituted or unsubstituted heteroarylene group having 3 to 60 nuclear carbon atoms, substituted or unsubstituted An unsubstituted fluorenylene group.
R is a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 60 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 60 nuclear carbon atoms, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. Or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, n is an integer of 0 to 5, and when n is 2 or more, a plurality of Rs may be the same or different and adjacent to each other. A plurality of R groups may be bonded to each other to form a carbocyclic aliphatic ring or a carbocyclic aromatic ring.
R ¹ is a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 60 nuclear carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 60 nuclear carbon atoms, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. Or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms or —L—Ar ¹ —Ar ² . The nitrogen-containing heterocyclic derivative represented by this.

HAr-L-Ar ¹ -Ar ² (C)
(In the formula, HAr is a nitrogen-containing heterocycle having 3 to 40 carbon atoms which may have a substituent, and L is a single bond and having 6 to 60 carbon atoms which may have a substituent. An arylene group, a C3-C60 heteroarylene group which may have a substituent, or a fluorenylene group which may have a substituent, and Ar ¹ is a carbon which may have a substituent. A divalent aromatic hydrocarbon group having 6 to 60 carbon atoms, Ar ² having an optionally substituted aryl group having 6 to 60 carbon atoms or an optionally substituted carbon atom 3 A nitrogen-containing heterocyclic derivative represented by ˜60 heteroaryl groups.

(Wherein X and Y are each independently a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, alkoxy group, alkenyloxy group, alkynyloxy group, hydroxy group, substituted or unsubstituted aryl group, substituted Or an unsubstituted heterocyclic ring or a structure in which X and Y are combined to form a saturated or unsaturated ring, and R _{1 to} R ₄ are each independently hydrogen, halogen atom, substituted or unsubstituted carbon number 1 To 6 alkyl groups, alkoxy groups, aryloxy groups, perfluoroalkyl groups, perfluoroalkoxy groups, amino groups, alkylcarbonyl groups, arylcarbonyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, azo groups, alkylcarbonyloxy Group, arylcarbonyloxy group, alkoxycarbonyloxy group, aryloxy group Bonyloxy, sulfinyl, sulfonyl, sulfanyl, silyl, carbamoyl, aryl, heterocyclic, alkenyl, alkynyl, nitro, formyl, nitroso, formyloxy, isocyano, cyanate, When an isocyanate group, a thiocyanate group, an isothiocyanate group or a cyano group, or two substituents are adjacent to each other, they are bonded to form a substituted or unsubstituted saturated or unsaturated ring. A silacyclopentadiene derivative represented by:

Wherein R _{1 to} R ₈ and Z ₂ are each independently a hydrogen atom, saturated or unsaturated hydrocarbon group, aromatic group, heterocyclic group, substituted amino group, substituted boryl group, alkoxy group or aryl. X, Y and Z ₁ each independently represents a saturated or unsaturated hydrocarbon group, aromatic group, heterocyclic group, substituted amino group, alkoxy group or aryloxy group, and Z ₁ and Z ₂ substituents may be bonded to each other to form a condensed ring, and n represents an integer of 1 to 3, and when n is 2 or more, Z ₁ may be different, provided that n is 1 , X, Y and R ₂ are methyl groups, and R ₈ is a hydrogen atom or a substituted boryl group, and n is 3 and Z ₁ is not a methyl group. .

[Wherein, Q ¹ and Q ² each independently represent a ligand represented by the following general formula (G), and L represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cyclohexane. An alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, —OR ¹ (R ¹ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, substituted or An unsubstituted aryl group, a substituted or unsubstituted heterocyclic group.) Or —O—Ga—Q ³ (Q ⁴ ) (Q ³ and Q ⁴ are the same as Q ¹ and Q ² ). Represents a quantifier. ]

[Wherein, rings A ¹ and A ² are 6-membered aryl ring structures condensed with each other which may have a substituent. ]

This metal complex has strong properties as an n-type semiconductor and has a large electron injection capability. Furthermore, since the generation energy at the time of complex formation is also low, the bond between the metal of the formed metal complex and the ligand is strengthened, and the fluorescence quantum efficiency as a light emitting material is also increased.
Specific examples of the substituents of the rings A ¹ and A ² that form the ligand of the general formula (G) include chlorine, bromine, iodine, halogen atoms of fluorine, methyl group, ethyl group, propyl group, Substituted or unsubstituted alkyl groups such as butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, trichloromethyl group, phenyl group, naphthyl group, 3-methyl Phenyl group, 3-methoxyphenyl group, 3-fluorophenyl group, 3-trichloromethylphenyl group, 3-trifluoromethylphenyl group, 3-nitrophenyl group and other substituted or unsubstituted aryl groups, methoxy group, n- Butoxy group, t-butoxy group, trichloromethoxy group, trifluoroethoxy group, pentafluoropropoxy group, 2,2,3,3-tetrafluoro group Substituted or unsubstituted alkoxy groups such as poxy group, 1,1,1,3,3,3-hexafluoro-2-propoxy group, 6- (perfluoroethyl) hexyloxy group, phenoxy group, p-nitrophenoxy Group, p-t-butylphenoxy group, 3-fluorophenoxy group, pentafluorophenyl group, substituted or unsubstituted aryloxy group such as 3-trifluoromethylphenoxy group, methylthio group, ethylthio group, t-butylthio group, Hexylthio group, octylthio group, trifluoromethylthio group and other substituted or unsubstituted alkylthio groups, phenylthio group, p-nitrophenylthio group, pt-butylphenylthio group, 3-fluorophenylthio group, pentafluorophenylthio Substitution of 3-group, 3-trifluoromethylphenylthio group, etc. Mono- or di-substituted amino groups such as unsubstituted arylthio group, cyano group, nitro group, amino group, methylamino group, diethylamino group, ethylamino group, diethylamino group, dipropylamino group, dibutylamino group, diphenylamino group, Acylamino groups such as bis (acetoxymethyl) amino group, bis (acetoxyethyl) amino group, bis (acetoxypropyl) amino group, bis (acetoxybutyl) amino group, hydroxyl group, siloxy group, acyl group, methylcarbamoyl group, dimethylcarbamoyl group Group, ethylcarbamoyl group, diethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group, carbamoyl group such as phenylcarbamoyl group, carboxylic acid group, sulfonic acid group, imide group, cyclopentane group, cyclohexyl group, etc. Group, phenyl group, naphthyl group, biphenylyl group, anthryl group, phenanthryl group, fluorenyl group, pyrenyl group, aryl group, pyridinyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, triazinyl group, indolinyl group, quinolinyl group, acridinyl group , Pyrrolidinyl group, dioxanyl group, piperidinyl group, morpholidinyl group, piperazinyl group, carbazolyl group, furanyl group, thiophenyl group, oxazolyl group, oxadiazolyl group, benzoxazolyl group, thiazolyl group, thiadiazolyl group, benzothiazolyl group, triazolyl group , Heterocyclic groups such as an imidazolyl group, a benzoimidazolyl group, and a pranyl group. Moreover, the above substituents may combine to form a further 6-membered aryl ring or heterocyclic ring.

A preferred form of the organic EL device of the present invention is a device containing a reducing dopant in an electron transporting region or an interface region between a cathode and an organic layer. Here, the reducing dopant is defined as a substance capable of reducing the electron transporting compound. Accordingly, various materials can be used as long as they have a certain reducibility, such as alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metals. At least selected from the group consisting of oxides, alkaline earth metal halides, rare earth metal oxides or rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, rare earth metal organic complexes One substance can be preferably used.
More specifically, preferable reducing dopants include Li (work function: 2.9 eV), Na (work function: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2). .16 eV) and Cs (work function: 1.95 eV), at least one alkali metal selected from the group consisting of Ca (work function: 2.9 eV), Sr (work function: 2.0 to 2.5 eV) And at least one alkaline earth metal selected from the group consisting of Ba (work function: 2.52 eV) and a work function of 2.9 eV or less is particularly preferred. Among these, a more preferable reducing dopant is at least one alkali metal selected from the group consisting of K, Rb, and Cs, more preferably Rb or Cs, and most preferably Cs. . These alkali metals have particularly high reducing ability, and the addition of a relatively small amount to the electron injection region can improve the light emission luminance and extend the life of the organic EL element. Further, as a reducing dopant having a work function of 2.9 eV or less, a combination of these two or more alkali metals is also preferable. Particularly, a combination containing Cs, for example, Cs and Na, Cs and K, Cs and Rb, A combination of Cs, Na and K is preferred. By including Cs in combination, the reducing ability can be efficiently exhibited, and by adding to the electron injection region, the emission luminance and the life of the organic EL element can be improved.

In the present invention, an electron injection layer composed of an insulator or a semiconductor may be further provided between the cathode and the organic layer. At this time, current leakage can be effectively prevented and the electron injection property can be improved. As such an insulator, it is preferable to use at least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides. If the electron injection layer is composed of these alkali metal chalcogenides or the like, it is preferable in that the electron injection property can be further improved. Specifically, preferable alkali metal chalcogenides include, for example, Li ₂ O, K ₂ O, Na ₂ S, Na ₂ Se, and Na ₂ O, and preferable alkaline earth metal chalcogenides include, for example, CaO, BaO. , SrO, BeO, BaS, and CaSe. Further, preferable alkali metal halides include, for example, LiF, NaF, KF, LiCl, KCl, and NaCl. Examples of preferable alkaline earth metal halides include fluorides such as CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ and BeF ₂ , and halides other than fluorides.
Further, as a semiconductor constituting the electron transport layer, an oxide containing at least one element of Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg, Si, Ta, Sb, and Zn. , Nitrides or oxynitrides, or a combination of two or more thereof. Moreover, it is preferable that the inorganic compound which comprises an electron carrying layer is a microcrystal or an amorphous insulating thin film. If the electron transport layer is composed of these insulating thin films, a more uniform thin film is formed, and pixel defects such as dark spots can be reduced. Examples of such inorganic compounds include the alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides described above.

(9) Cathode As the cathode, in order to inject electrons into the electron injecting / transporting layer or the light emitting layer, a material having a small work function (4 eV or less), an alloy, an electrically conductive compound and a mixture thereof are used as electrode materials. Used. Specific examples of such electrode materials include sodium, sodium / potassium alloy, magnesium, lithium, magnesium / silver alloy, aluminum / aluminum oxide, aluminum / lithium alloy, indium, and rare earth metals.
The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.
Here, when light emitted from the light emitting layer is taken out from the cathode, it is preferable that the transmittance with respect to the light emitted from the cathode is larger than 10%.
The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

(10) Insulating layer Since an organic EL element applies an electric field to an ultra-thin film, pixel defects due to leakage or short-circuiting are likely to occur. In order to prevent this, it is preferable to insert an insulating thin film layer between the pair of electrodes.
Examples of materials used for the insulating layer include aluminum oxide, lithium fluoride, lithium oxide, cesium fluoride, cesium oxide, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, aluminum nitride, titanium oxide, silicon oxide, and oxide. Germanium, silicon nitride, boron nitride, molybdenum oxide, ruthenium oxide, vanadium oxide, and the like may be used, and a mixture or laminate of these may be used.

(11) Manufacturing method of organic EL element An anode, a first hole injection layer, an acceptor layer, a second hole injection layer, a light emitting layer, and an electron injection / transport layer as necessary are formed by the materials and the formation methods exemplified above. Furthermore, an organic EL element can be produced by forming a cathode. Moreover, an organic EL element can also be produced from the cathode to the anode in the reverse order.
The following describes an example of manufacturing an organic EL device having a structure in which an anode / first hole injection layer / acceptor layer / second hole injection layer / light emitting layer / electron injection layer / cathode are sequentially provided on a translucent substrate. To do.
First, a thin film made of an anode material is formed on a suitable light-transmitting substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. Next, a first hole injection layer is provided on the anode. As described above, the first hole injection layer can be formed by a vacuum deposition method, a spin coating method, a casting method, an LB method, or the like, but it is easy to obtain a homogeneous film and pinholes are generated. It is preferable to form by a vacuum evaporation method from the point of being hard to do. When forming the first hole injection layer by vacuum deposition, the deposition conditions are the compound used (material of the first hole injection layer), the crystal structure and recombination structure of the target first hole injection layer, etc. Generally, the deposition source temperature is 50 to 450 ° C., the degree of vacuum is 10 ⁻⁷ to 10 ⁻³ Torr, the deposition rate is 0.01 to 50 nm / second, the substrate temperature is −50 to 300 ° C., and the film thickness is 5 nm to 5 μm. It is preferable to select appropriately.

Next, an acceptor layer and a second hole injection layer are sequentially laminated on the first hole injection layer in the same manner.
Next, the formation of the light emitting layer in which the light emitting layer is provided on the second hole injecting layer is also performed by using a desired organic light emitting material to form a thin film of the organic light emitting material by a method such as vacuum deposition, sputtering, spin coating, or casting. However, it is preferably formed by a vacuum deposition method from the viewpoint that a homogeneous film is easily obtained and pinholes are hardly generated. When the light emitting layer is formed by the vacuum vapor deposition method, the vapor deposition condition varies depending on the compound used, but it can be generally selected from the same condition range as that of the hole injection layer.
Next, an electron injection layer is provided on the light emitting layer. As with the hole injection layer and the light emitting layer, it is preferable to form by a vacuum evaporation method because it is necessary to obtain a homogeneous film. Deposition conditions can be selected from the same condition range as the hole injection layer and the light emitting layer.
The aromatic amine derivative can be co-deposited with other materials when the vacuum deposition method is used. Moreover, when using a spin coat method, it can be made to contain by mixing with another material.
Finally, an organic EL element can be obtained by laminating a cathode.
The cathode is made of metal, and vapor deposition or sputtering can be used. However, vacuum deposition is preferred to protect the underlying organic layer from damage during film formation.
The organic EL element is preferably manufactured from the anode to the cathode consistently by a single vacuum.

The formation method of each layer of the organic EL element of the present invention is not particularly limited, and a conventionally known formation method such as a vacuum evaporation method, a spin coating method, or the like can be used, and a vacuum evaporation method, a molecular beam evaporation method (MBE method) or It can be formed by a known method using a coating method such as a dipping method of a solution dissolved in a solvent, a spin coating method, a casting method, a bar coating method, or a roll coating method.
The film thickness of each organic layer of the organic EL device of the present invention is not particularly limited. Generally, if the film thickness is too thin, defects such as pinholes are likely to occur. Conversely, if it is too thick, a high applied voltage is required and the efficiency is deteriorated. Therefore, the range of several nm to 1 μm is usually preferable.
When a direct current voltage is applied to the organic EL element, light emission can be observed by applying a voltage of 5 to 40 V with a positive polarity of the anode and a negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when alternating voltage is applied, uniform light emission is observed only when the anode has a positive polarity and the cathode has a negative polarity. The waveform of the alternating current to be applied may be arbitrary.

Hereinafter, the present invention will be described in more detail based on synthesis examples and examples.
The structural formulas of Intermediates 1 to 4 produced in Synthesis Examples 1 to 4 are as follows.

Synthesis Example 1 (Synthesis of Intermediate 1)
Under a stream of argon, 750 g of phenylboronic acid, 1000 g of 2-bromothiophene, 142 g of tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ), 2M sodium carbonate (Na ₂ CO ₃ ) in a 50 L reaction vessel 9 L of the solution and 15 L of dimethoxyethane were added, followed by reaction at 80 ° C. for 8 hours. The reaction solution was extracted with toluene / water and dried over anhydrous sodium sulfate. This was concentrated under reduced pressure, and the resulting crude product was subjected to column purification to obtain 786 g of white powder.
Under an argon stream, 786 g of the compound obtained above and 8 L of DMF (dimethylformamide) were placed in a 20 L reaction vessel, and then 960 g of NBS (N-bromosuccinimide) was slowly added, and reacted at room temperature for 12 hours. Extracted with hexane / water and dried over anhydrous sodium sulfate. This was concentrated under reduced pressure, and the resulting crude product was subjected to column purification to obtain 703 g of white powder. The intermediate body 1 was identified by analysis of FD-MS.

Synthesis Example 2 (Synthesis of Intermediate 2)
Under an argon stream, 703 g of intermediate 1 and 7 L of dehydrated THF (tetrahydrofuran) were added to a 20 L reaction vessel, and cooled to −30 ° C. 2.3 L of n-butyllithium (n-BuLi, 1.6M hexane solution) was added and reacted for 1 hour. After cooling to −70 ° C., 1658 g of triisopropyl borate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. The temperature was raised slowly, and the mixture was stirred at room temperature for 1 hour. 1.7 L of 10% hydrochloric acid solution was added and stirred. The mixture was extracted with ethyl acetate and water, and the organic layer was washed with water. The extract was dried over anhydrous sodium sulfate and the solvent was distilled off. By washing with hexane, 359 g of white powder was obtained.
Under a stream of argon, 506 g of 5-phenyl-2-thiopheneboronic acid obtained above, 600 g of 4-iodobromobenzene, tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ) in a 20 L reaction vessel. 41 g of 2M sodium carbonate (Na ₂ CO ₃ ) solution (2.6 L) and dimethoxyethane (10 L) were added, followed by reaction at 80 ° C. for 8 hours. The reaction solution was extracted with toluene / water and dried over anhydrous sodium sulfate. This was concentrated under reduced pressure, and the resulting crude product was purified by column to obtain 277 g of white powder. The intermediate body 2 was identified by analysis of FD-MS.

Synthesis Example 3 (Synthesis of Intermediate 3)
Under an argon stream, 5.5 g of aniline, 15.7 g of intermediate 2, 6.8 g of sodium t-butoxy (manufactured by Hiroshima Wako), 0.46 g of tris (dibenzylideneacetone) dipalladium (0) (manufactured by Aldrich) ) And 300 mL of dehydrated toluene, and reacted at 80 ° C. for 8 hours.
After cooling, 500 mL of water was added, the mixture was filtered through Celite, and the filtrate was extracted with toluene and dried over anhydrous magnesium sulfate. This was concentrated under reduced pressure, and the resulting crude product was purified by column, recrystallized from toluene, filtered, and dried to obtain 10.8 g of a pale yellow powder. The intermediate body 3 was identified by analysis of FD-MS.

Synthesis Example 4 (Synthesis of Intermediate 4)
In a 200 mL three-necked flask, 20.0 g of 4-bromobiphenyl (product of Tokyo Chemical Industry Co., Ltd.), 8.64 g of sodium t-butoxy (manufactured by Wako Pure Chemical Industries), and 84 mg of palladium acetate (manufactured by Wako Pure Chemical Industries, Ltd.) were placed. . Add a stir bar, set rubber caps on both sides of the flask, set a reflux snake tube in the center of the flask, set a balloon filled with three-way cock and argon gas on it, and evacuate the system three times using a vacuum pump. The argon gas in the balloon was replaced.
Next, 120 mL of dehydrated toluene (manufactured by Hiroshima Wako Co., Ltd.), 4.08 mL of benzylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 338 μL of tris-t-butylphosphine (manufactured by Aldrich, 2.22 mol / L toluene solution), and rubber with a syringe Added through a septum and stirred for 5 minutes at room temperature. Next, the flask was set in an oil bath, and the temperature was gradually raised to 120 ° C. while stirring the solution. After 7 hours, the flask was removed from the oil bath to terminate the reaction, and the mixture was left under an argon atmosphere for 12 hours. The reaction solution was transferred to a separatory funnel, and 600 mL of dichloromethane was added to dissolve the precipitate. After washing with 120 mL of saturated brine, the organic layer was dried over anhydrous potassium carbonate. The solvent of the organic layer obtained by removing potassium carbonate by filtration was distilled off, and 400 mL of toluene and 80 mL of ethanol were added to the resulting residue, and the mixture was heated to 80 ° C. with a drying tube to completely dissolve the residue. Then, it was left to stand for 12 hours and recrystallized by cooling to room temperature. The precipitated crystals were separated by filtration and vacuum dried at 60 ° C. to obtain 13.5 g of N, N-di- (4-biphenylyl) -benzylamine. In a 300 mL one-necked flask, 1.35 g of N, N-di- (4-biphenylyl) -benzylamine and 135 mg of palladium-activated carbon (manufactured by Hiroshima Wako Co., Ltd., palladium content of 10% by weight) were added. 20 mL was added and dissolved. Next, after putting a stir bar in the flask, a three-way cock equipped with a balloon filled with 2 L of hydrogen gas was attached to the flask, and the inside of the flask system was replaced with hydrogen gas 10 times using a vacuum pump. The reduced hydrogen gas was refilled and the hydrogen gas volume was again brought to 2 L, and then the solution was vigorously stirred at room temperature. After stirring for 30 hours, 100 mL of dichloromethane was added, and the catalyst was filtered off. Next, the obtained solution was transferred to a separatory funnel, washed with 50 mL of a saturated aqueous solution of sodium hydrogen carbonate, the organic layer was separated, and dried over anhydrous potassium carbonate. After filtration, the solvent was distilled off, and 50 mL of toluene was added to the resulting residue for recrystallization. The precipitated crystals were separated by filtration and vacuum dried at 50 ° C. to obtain 0.99 g of di-4-biphenylylamine.
Under an argon stream, 10 g of di-4-biphenylylamine, 9.7 g of 4,4′-dibromobiphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.), 3 g of sodium t-butoxy (manufactured by Hiroshima Wako), bis (triphenylphosphine) palladium chloride (II) 0.5 g (manufactured by Tokyo Chemical Industry Co., Ltd.) and 500 mL of xylene were added and reacted at 130 ° C. for 24 hours. After cooling, 1000 mL of water was added, the mixture was filtered through Celite, and the filtrate was extracted with toluene and dried over anhydrous magnesium sulfate. This was concentrated under reduced pressure, and the resulting crude product was purified by column, recrystallized from toluene, filtered, and dried to give 9.1 g of 4′-bromo-N, N— Dibiphenylyl-4-amino-1,1′-biphenyl (intermediate 4) was obtained.

  The structural formula of Compound H1, which is the above-described aromatic amine derivative produced in Synthesis Example 5, is as follows.

Synthesis Example 5 (Synthesis of Compound H1)
Under an argon stream, 6.5 g of Intermediate 3, 11.0 g of Intermediate 4, 2.6 g of t-butoxy sodium (manufactured by Hiroshima Wako), 92 mg of tris (dibenzylideneacetone) dipalladium (0) (manufactured by Aldrich) ), 42 mg of tri-t-butylphosphine and 100 mL of dehydrated toluene were added and reacted at 80 ° C. for 8 hours.
After cooling, 500 mL of water was added, the mixture was filtered through Celite, and the filtrate was extracted with toluene and dried over anhydrous magnesium sulfate. This was concentrated under reduced pressure, and the resulting crude product was purified by column, recrystallized from toluene, filtered, and dried to obtain 7.9 g of a pale yellow powder. The compound H1 was identified by analysis of FD-MS (field desorption mass spectrum).

Example 1 (Manufacture of an organic EL element)
A glass substrate with an ITO transparent electrode having a thickness of 25 mm × 75 mm × 1.1 mm (manufactured by Geomatic Co., Ltd.) was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes and then UV ozone cleaning for 30 minutes.
The glass substrate with the transparent electrode line after the cleaning is mounted on the substrate holder of the vacuum evaporation apparatus, and first, the transparent electrode is covered on the surface on which the transparent electrode line of indium tin oxide having a film thickness of 130 nm is formed. The compound H1 film having a thickness of 60 nm was formed. This H1 film functions as a first hole injection layer. The following compound HAT was formed to a thickness of 5 nm on this H1 film to form an acceptor layer. Next, the following compound NPD was formed into a second hole injection layer with a film thickness of 50 nm. Furthermore, the following compound HT1 was formed into a film with a film thickness of 15 nm, and it was set as the positive hole transport layer. Further, the following compound BH and compound BD were co-evaporated so that the compound BD was 5% by mass to form a light emitting layer having a film thickness of 25 nm.
On this film, the following compound ET1 was deposited to a thickness of 10 nm to form a first electron transport layer. Thereafter, the following compound ET2 (50% by mass) and the following compound Liq (50% by mass), which is a reducing dopant, were subjected to binary evaporation to form a second electron transport layer having a thickness of 15 nm. Subsequently, Compound Liq was vapor-deposited alone to form a film having a thickness of 1 nm. Finally, metal Al was vapor-deposited with a film thickness of 80 nm to form a metal cathode, thereby forming the organic EL device of the present invention.
In addition, the obtained organic EL device was subjected to an energization test at a current density of 10 mA / cm ² , the luminance was measured using Minolta CS1000, and the luminous efficiency was calculated by measuring the voltage. Furthermore, the chromaticity coordinates of the light emission were also measured. The measurement results are shown in Table 1.
Furthermore, FIG. 2 shows a comparison between the relative luminance with an initial luminance of 1 in the energization test of the obtained organic EL element and the driving time.

Comparative Example 1 (Manufacture of organic EL elements)
An organic EL device was produced in the same manner as in Example 1 except that the first hole injection layer was not formed and the thickness of the second hole injection layer was changed to 110 nm. Table 1 shows the luminance, voltage, luminous efficiency, and chromaticity coordinates of the luminescent color in the energization test.
Furthermore, FIG. 2 shows a comparison between the relative luminance with an initial luminance of 1 in the energization test of the obtained organic EL element and the driving time.

Comparative Example 2 (Production of organic EL device)
An organic EL device was produced in the same manner as in Example 1 except that the first hole injection layer was formed using NPD instead of Compound H1. Table 1 shows the luminance, voltage, luminous efficiency, and chromaticity coordinates of the luminescent color in the energization test.
Furthermore, FIG. 2 shows a comparison between the relative luminance with an initial luminance of 1 in the energization test of the obtained organic EL element and the driving time.

  As described above in detail, the aromatic amine derivative of the present invention has high luminous efficiency, excellent device performance stability, and long life, and thus excellent power saving.

Claims (12)

An organic electroluminescence device having a light emitting layer between an anode and a cathode, comprising a first hole injection layer, an acceptor layer, and a second hole injection layer in that order between the anode and the light emitting layer, the first hole injection layer Is an organic electroluminescence device containing an aromatic amine derivative represented by the following general formula (1).

[Wherein, L ₁ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{1 to} Ar ₄ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In General Formula (1), those other than those represented by General Formula (2) among Ar _{1 to} Ar ₄ are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. ] The organic electroluminescence device according to claim 1, wherein the group represented by the general formula (2) is represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. } The organic electroluminescent element according to claim 1 or 2, wherein the acceptor layer contains an acceptor material represented by the following general formula (7).

(In the formula, R ^{11 to} R ¹⁶ are each independently a cyano group, a nitro group, a sulfonyl group, a carbonyl group, a trifluoromethyl group, or a halogen atom.) The organic electroluminescent element according to claim ₁ , wherein Ar ₁ in the general formula (1) is a group represented by the general formula (2). The organic electroluminescent element according to claim 1, wherein L ₁ in the general formula (1) is a biphenylylene group, a terphenylylene group, or a fluorenylene group. L ₂ is a phenylene group in the general formula (2), the organic electroluminescent device according to any one of claims 1 to 5 is a biphenylene group or fluorenylene group. Formula R ₁ is a phenyl group in (2), the organic electroluminescent device according to claim 1 is naphthyl or phenanthrenyl group. An organic electroluminescence device having a light emitting layer between an anode and a cathode, comprising a first hole injection layer, an acceptor layer, and a second hole injection layer in that order between the anode and the light emitting layer, the first hole injection layer Is an organic electroluminescence device containing an aromatic amine derivative represented by any one of the following general formulas (4) to (6).

[Wherein, L _{5 to} L ₁₂ each independently represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
At least one of Ar _{5 to} Ar ₉ is a group represented by the following general formula (2).
At least one of Ar _{10 to} Ar ₁₅ is a group represented by the following general formula (2).
At least one of Ar _{16 to} Ar ₂₁ is a group represented by the following general formula (2).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a halogen atom, or a cyano group.
a is an integer of 1 to 3.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. }
In general formulas (4) to (6), except for those represented by general formula (2) among Ar _{5 to} Ar ₂₁ , each independently or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms. It is. ] The organic electroluminescence device according to claim 8, wherein the group represented by the general formula (2) is represented by the following general formula (3).

{In the formula, R ₁ represents a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
L ₂ represents a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms. } The organic electroluminescent element according to claim 8 or 9, wherein the acceptor layer contains an acceptor material represented by the following general formula (7).

(In the formula, R ^{11 to} R ¹⁶ are each independently a cyano group, a nitro group, a sulfonyl group, a carbonyl group, a trifluoromethyl group, or a halogen atom.)   The organic electroluminescent element in any one of Claims 1-10 which contains an arylamine compound in a light emitting layer.   The organic electroluminescence element according to claim 1, which emits blue light.

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