JP6754185B2 - Organic functional materials for organic electroluminescence devices, display devices, lighting devices and electronic devices - Google Patents

Description

The present invention relates to organic functional materials for organic electroluminescence devices, display devices, lighting devices and electronic devices. More specifically, the present invention relates to an organic electroluminescence device having high luminous efficiency, long luminous life, and improved storage stability at high temperature.

An organic electroluminescence device (hereinafter, also referred to as an “organic EL device”) is a thin-film type all-solid-state device composed of an organic thin film layer (single layer or multilayer) containing an organic luminescent substance between an anode and a cathode. Is. When a voltage is applied to such an organic EL element, electrons are injected from the cathode into the organic thin film layer and holes are injected from the anode, and these are recombined in the light emitting layer (organic light emitting substance-containing layer) to generate excitons. The organic EL element is a light emitting element that utilizes the emission of light (fluorescence / phosphorescence) from these excitons, and is a technology expected as a next-generation flat display and lighting.

Furthermore, since the University of Princeton reported an organic EL element that uses phosphorescence emission from an excited triplet, which can achieve about four times the emission efficiency in principle compared to an organic EL element that uses fluorescence emission. Starting with the development of materials that exhibit phosphorescence at room temperature, research and development of the layer structure of light emitting elements and electrodes are being carried out all over the world.

In this way, the phosphorescence emission method has a very high potential, but in an organic EL device that uses phosphorescence emission, it is significantly different from that that uses fluorescence emission, and a method for controlling the position of the emission center, particularly Recoupling inside the light emitting layer and how stable the light emission can be achieved is an important technical issue for improving the efficiency and life of the device.

Therefore, in recent years, a multi-layer laminated type device having a hole transport layer located on the anode side of the light emitting layer, an electron transport layer located on the cathode side of the light emitting layer, and the like adjacent to the light emitting layer is well known. ing. Further, as the light emitting layer, a mixed layer using a phosphorescent compound as a light emitting dopant and a host compound is often used.

On the other hand, from the viewpoint of materials, there are great expectations for the creation of new materials for improving device performance. In particular, as a host compound of a phosphorescent compound, a material for organic EL using a nitrogen-containing polycondensed ring compound has been reported (see, for example, Patent Documents 1 and 2).

However, in these compounds described in Patent Documents 1 and 2, when used as an organic EL device material, the life and luminous efficiency of the device have been improved to some extent, but they are not sufficient and further improvement has been required. Further, it has been found that the organic EL device using these compounds has a drawback of being inferior in thermal stability, that is, a drawback that the performance changes greatly with time when stored or used at a high temperature. Further, Patent Documents 3 and 4 disclose that compounds having an aromatic hydrocarbon group at the 4-position and a nitrogen-containing heterocyclic group at the 6-position of dibenzofuran are used as organic electronics materials. Even if a compound is used, it cannot be said that the storage stability at a high temperature is sufficient, and further improvement is required.

Japanese Patent Application Laid-Open No. 2013-510803 International Publication No. 2015/014434 U.S. Patent Application Publication No. 2015/0259221 Korean Publication No. 2015-0031396

The present invention has been made in view of the above problems and situations, and the problem to be solved is that a novel aromatic heterocyclic derivative is used as an organic functional material, the luminous efficiency is high, the luminous life is long, and particularly high temperature. It is to provide an organic electroluminescence element with improved storage stability underneath. Another object of the present invention is to provide a display device and a lighting device provided with the organic electroluminescence element. Furthermore, it is to provide an organic functional material for an electronic device containing a novel aromatic heterocyclic derivative.

As a result of investigating the causes of the above problems in order to solve the above problems, the present inventor has found that an aromatic heterocyclic derivative having a specific structure is effective in solving the above problems, and has reached the present invention.

That is, the above problem according to the present invention is solved by the following means.

1. An organic electroluminescence element in which an organic functional layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one of the organic functional layers has a structure represented by the following general formula (1). An organic electroluminescence element containing an aromatic heterocyclic derivative.

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。ただし、下記一般式（Ｅ１）〜一般式（Ｅ８）で表される構造を有する化合物を除く。）

（式中、Ｘは、酸素原子又は硫黄原子を表す。）
２．前記一般式（１）で表される構造を有する芳香族複素環誘導体が、下記一般式（１−１）〜（１−１６）で表される構造のうちのいずれかで表される構造を有することを特徴とする第１項に記載の有機エレクトロルミネッセンス素子。

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not bond with each other to form a ring, and do not form a ring with other parts in the general formula (1). X is an oxygen atom or a sulfur atom. However, compounds having a structure represented by the following general formulas (E1) to (E8) are excluded. )

(In the formula, X represents an oxygen atom or a sulfur atom.)
2. The aromatic heterocyclic derivative having the structure represented by the general formula (1) has a structure represented by any of the structures represented by the following general formulas (1-1) to (1-16). The organic electroluminescence device according to the first item, which is characterized by having.

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not combine with each other to form a ring, nor do they form a ring with other parts of the general formulas (1-1) to (1-16). X represents an oxygen atom or a sulfur atom. However, in each of the general formula (1-8), the general formula (1-14) and the general formula (1-16), R _{1 to} R ₅ are all hydrogen. Except for atoms.)
3. The organic electroluminescence device according to the first or second term, wherein Ar ₁ and Ar ₂ each represent a monocyclic aryl group.

4. The organic electroluminescence device according to any one of the items 1 to 3, wherein each of R _{1 to} R ₅ represents a hydrogen atom.

5. Any one of the first to fourth terms, wherein R _{1 to} R ₅ each represent a hydrogen atom, and Ar ₁ and Ar ₂ each represent a monocyclic aryl group. The organic electroluminescence device described in the section.

6. The organic electroluminescence device according to any one of items 1 to 5, wherein the light emitting layer contains the aromatic heterocyclic derivative.

7. The organic electroluminescence device according to any one of items 1 to 6, wherein the light emitting layer contains the aromatic heterocyclic derivative as a host compound.

8. The organic electroluminescence device according to any one of items 1 to 7, wherein the light emitting layer contains a phosphorescent dopant.

9. The organic electroluminescence device according to any one of items 1 to 8, wherein the light emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative.

10. A display device comprising the organic electroluminescence device according to any one of items 1 to 9.

11. A lighting device comprising the organic electroluminescence device according to any one of items 1 to 9.

12. An organic functional material for an electronic device, which contains an aromatic heterocyclic derivative having a structure represented by the following general formula (1).

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。ただし、下記一般式（Ｅ１）〜一般式（Ｅ８）で表される構造を有する化合物を除く。）

（式中、Ｘは、酸素原子又は硫黄原子を表す。）

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not bond with each other to form a ring, and do not form a ring with other parts in the general formula (1). X is an oxygen atom or a sulfur atom. However, compounds having a structure represented by the following general formulas (E1) to (E8) are excluded. )

(In the formula, X represents an oxygen atom or a sulfur atom.)

INDUSTRIAL APPLICABILITY According to the present invention, an organic electroluminescence device using a novel aromatic heterocyclic derivative as an organic functional material, which has high luminous efficiency, long luminous life, and particularly improved storage stability at high temperatures by the above means. Can be provided. Further, it is possible to provide a display device and a lighting device provided with the organic electroluminescence element. Furthermore, it is possible to provide an organic functional material for an electronic device containing a novel aromatic heterocyclic derivative.

Although the mechanism of expression or mechanism of action of the effects of the present invention has not been clarified, it is inferred as follows.

In order to use it as an electron-transporting material or an electron-transporting host compound, it is preferable that excitons are not generated on the compound, and as a means for suppressing the exciton, the highest occupied molecular orbital (HOMO) of the electron-transporting compound is used. ) It is conceivable to lower the level (also called "deep").

In order to have electron transportability, it is known as a useful means to have a structure with many N atoms such as triazine, but as a result of diligent and trial-and-error studies by the present inventor, dibenzofuran or By combining with dibenzothiophene, a compound having a structure represented by the general formula (1) according to the present invention having a deep HOMO level derived from HOMO of dibenzofuran or dibenzothiophene could be designed.

On the other hand, when manufacturing an electronic device such as an organic EL element, it is known that a film formed by molecules having many free-rotating parts has a large variation in film quality when the molecules move in the film. ing.

For example, when a film is formed by thin-film deposition, immediately after the molecules are deposited on the film, the molecules are in a free-rotating state, and it takes time until a stable film is formed. Further, it is presumed that the molecules move when heat is applied and when a drive voltage is applied, but the performance of a film having such a large fluctuation tends to fluctuate and preferable performance tends not to be obtained. Therefore, a compound in which the movement of molecules in the membrane is as small as possible is preferable.

It is presumed that the compound having the structure represented by the general formula (1) according to the present invention has few places where it can freely rotate, and therefore, even if molecules move in the membrane, the change in the entire membrane is small and stable performance can be obtained. Will be done.

Further, a structure such as triphenylene having a large π-conjugated surface that easily associates has high crystallinity and is often not preferable for the purpose of obtaining an amorphous film, but the structure represented by the general formula (1) according to the present invention. Since the compound having the above does not have such a structure, it is considered that an amorphous film is easily formed.

Schematic perspective view showing an example of the configuration of the display device of the present invention. Schematic perspective view showing an example of the configuration of the display unit A shown in FIG. Schematic perspective view showing an example of a lighting device using the organic EL element of the present invention. Schematic cross-sectional view showing an example of a lighting device using the organic EL element of the present invention.

The organic electroluminescence element of the present invention is an organic electroluminescence element in which an organic functional layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one of the organic functional layers has the above general formula ( It is characterized by containing an aromatic heterocyclic derivative having the structure represented by 1). This feature is a technical feature common to the inventions according to each claim.

In the embodiment of the present invention, from the viewpoint of expressing the effect of the present invention, the aromatic heterocyclic derivative having the structure represented by the general formula (1) is a general formula (1-1) to (1-16). It is preferable to have a structure represented by any one of the structures represented by).

In particular, Ar ₁ and Ar ₂ each represent a monocyclic aryl group, R _{1 to} R ₅ each represent a hydrogen atom, or R _{1 to} R ₅ represent a hydrogen atom, respectively. , A hydrogen atom, and Ar ₁ and Ar ₂ each represent a monocyclic aryl group.

In the present invention, from the viewpoint of more effectively utilizing the characteristics of the aromatic heterocyclic derivative, it is preferable that the light emitting layer contains the aromatic heterocyclic derivative, and further, the light emitting layer is the aromatic heterocyclic derivative. It is preferable to contain a ring derivative as a host compound.

From the same viewpoint, it is preferable that the light emitting layer contains a phosphorescent dopant, and that the light emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative.

The organic electroluminescence element of the present invention can be suitably provided in a display device or a lighting device.

Further, the aromatic heterocyclic derivative having the structure represented by the general formula (1) can be suitably used as an organic functional material for an electronic device.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

《Organic electroluminescence element》
The organic electroluminescence element of the present invention is an organic electroluminescence element in which an organic functional layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one of the organic functional layers has the following general formula ( It is characterized by containing an aromatic heterocyclic derivative having the structure represented by 1). The aromatic heterocyclic derivative will be described in detail below.

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。ただし、下記一般式（Ｅ１）〜一般式（Ｅ８）で表される構造を有する化合物を除く。）

（式中、Ｘは、酸素原子又は硫黄原子を表す。）
一般式（１）中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、置換若しくは無置換の炭素数１〜１２のアルキル基、又は、置換若しくは無置換の単環のアリール基（ただし、ヘテロアリール基は含まないものとする。）を表す。Ａｒ_１及びＡｒ_２は、好ましくは、置換若しくは無置換の単環のアリール基である。 <Aromatic heterocyclic derivative having a structure represented by the general formula (1)>

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not bond with each other to form a ring, and do not form a ring with other parts in the general formula (1). X is an oxygen atom or a sulfur atom. However, compounds having a structure represented by the following general formulas (E1) to (E8) are excluded. )

(In the formula, X represents an oxygen atom or a sulfur atom.)
In the general formula (1), Ar ₁ and Ar ₂ are independently substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms, or substituted or unsubstituted monocyclic aryl groups (however, heteroaryl groups). Is not included.) Ar ₁ and Ar ₂ are preferably substituted or unsubstituted monocyclic aryl groups.

The alkyl group having 1 to 12 carbon atoms represented by Ar ₁ or Ar ₂ does not inhibit the function of the aromatic heterocyclic derivative having the structure represented by the general formula (1) according to the present invention. It may be linear or have a branched structure, or it may have a cyclic structure such as a cycloalkyl group.

Examples of alkyl groups having 1 to 12 carbon atoms represented by Ar ₁ or Ar ₂ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl. Examples thereof include a group, an undecyl group, a dodecyl group, an isopropyl group, a neopentyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a cyclooctyl group.

Examples of the monocyclic aryl group represented by Ar ₁ or Ar ₂ (also referred to as an aromatic hydrocarbon ring group) include a phenyl group, a biphenyl group, a terphenyl group, a quarter phenyl group, and the like.

For the purpose of maintaining the excited triplet energy level (T ₁ energy level) of the compound of the present invention appropriately, the aryl groups represented by Ar ₁ or Ar ₂ include phenyl group, biphenyl group, turphenyl group, and A quarter phenyl group is preferred.

The above-mentioned alkyl group and aryl group represented by Ar ₁ or Ar ₂ may each have a further substituent as long as the function of the compound of the present invention is not impaired, and as a specific example of such a substituent. Is a group similar to the substituent represented by R _{1 to} R ₅ described later.

Preferably, Ar ₁ and Ar ₂ are aryl groups, more preferably substituted or unsubstituted phenyl groups.

R _{1 to} R ₅ independently represent a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group and a pentadecyl group. More preferably, R _{1 to} R ₅ are hydrogen atoms.

R _{1 to} R ₅ do not combine with each other to form a ring. In addition, it does not form a ring with other parts in the general formula (1).

Alkyl and aryl groups represented by Ar ₁ or _{A r2,} and the alkyl group represented by _R 1 to R ₅ may have a substituent.

Examples of these substituents include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group and a pentadecyl group. Group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (eg, ethynyl group, propargyl group, etc.) Also referred to as an aromatic hydrocarbon ring group, an aromatic carbon ring group, an aryl group, etc., for example, a phenyl group, a p-chlorophenyl group, a mesityl group, a trill group, a xsilyl group, a naphthyl group, an anthryl group, an azulenyl group, an acenaphthenyl group, Fluolenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrazil group, pyrimidinyl group, triadyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl) Group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazole-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, Isooxazolyl group, isothiazolyl group, frazayl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, azacarbazolyl group (carbon atoms constituting the carbazole ring of the carbazolyl group) Any one or more of the above is replaced with a nitrogen atom), quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholic group, oxazolidyl). Groups, etc.), alkoxy groups (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.) Etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, methylthio group, ethylthio group, propylthio group, etc.) For example, cyclopentylthio group, cyclohexylthio group, etc., arylthio group (eg, phenyl) Thio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxy) Carbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecyl Aminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-Ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyl) Oxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino Group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylamino Carbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido) Group, ethyl ureido group, pentyl ureido group, cyclohexyl ureido group, octyl ureido group, dodecyl ureido group, phenyl ureido group, naphthyl ureido group, 2-pyridyl aminoure Ido group, etc.), sulfinyl group (eg, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc. ), Alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (eg, phenylsulfonyl group) , Naftylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, Naftylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), fluoride hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, penta) Fluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group and the like.

These substituents may be further substituted by the above-mentioned substituents, and a plurality of these substituents may be bonded to each other to form a ring structure.

X represents an oxygen atom or a sulfur atom.

In the present invention, in particular, the Ar ₁ and Ar ₂ each represent a monocyclic aryl group, the R _{1 to} R ₅ each represent a hydrogen atom, or the R _{1 to} R ₅ However, it is preferable that Ar ₁ and Ar ₂ each represent a hydrogen atom, and Ar ₁ and Ar ₂ each represent a monocyclic aryl group.

In the embodiment of the present invention, the aromatic heterocyclic derivative having the structure represented by the general formula (1) is among the structures represented by the following general formulas (1-1) to (1-16). It is preferable to have a structure represented by either.

In the general formulas (1-1) to (1-16), Ar ₁ , Ar ₂ , R _{1 to} R ₅ and X have the same meaning as those in the general formula (1). However, in each of the general formula (1-8), the general formula (1-14) and the general formula (1-16), the cases where R _{1 to} R ₅ are all hydrogen atoms are excluded. )

Specific examples and reference examples of preferable aromatic heterocyclic derivatives are shown below, but the present invention is not limited thereto.

In the present invention, as described above, in particular, the Ar ₁ and Ar ₂ each represent a monocyclic aryl group, the R _{1 to} R ₅ each represent a hydrogen atom, or the above. It is preferable that R _{1 to} R ₅ each represent a hydrogen atom, and Ar ₁ and Ar ₂ each represent a monocyclic aryl group.

<Example of synthesis of exemplary compound>
The method for synthesizing the exemplified compound 120 will be described below.

The synthetic route and method for synthesizing the exemplified compound 120 are as follows. In addition, other exemplified compounds can be basically synthesized by the same method as the following synthesis method by adopting appropriate raw materials and reaction conditions for each.

(Synthesis of Intermediate 1)
21.2 g of dibenzofuran-4-boronic acid and 26.5 g of iodobenzene were dissolved in 310 ml of toluene, 2.77 g of 1,1'-bis (diphenylphosphino) ferrocene and 2.88 g of bis (dibenzylideneacetone). ) Palladium, 27.6 g of potassium carbonate and 60 ml of water were added, and the mixture was stirred at 80 ° C. for 17 hours under a nitrogen atmosphere. The reaction mixture was allowed to cool, the organic layer was washed with water, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained concentrate was purified by silica gel column chromatography to obtain 19.2 g of Intermediate 1.

(Synthesis of Intermediate 2)
17.1 g of Intermediate 1 was dissolved in 260 ml of dehydrated THF, 135 ml of n-butyllithium (1.6 mol / L hexane solution) was added at −40 ° C. or lower under a nitrogen atmosphere, and the mixture was stirred at −40 ° C. for 1 hour. Then, the temperature of the reaction solution was raised to 0 ° C., the mixture was stirred for 4 hours, the reaction solution was cooled again, 10.9 g of trimethoxyborane was added dropwise at −10 ° C. or lower, and the mixture was stirred at room temperature for 1 hour. Dilute hydrochloric acid was added to the reaction solution, and the mixture was stirred for 1 hour and then allowed to stand to remove the aqueous layer. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained Intermediate 2 Concentrate was used as it was in the next step.

(Synthesis of Exemplified Compound 120)
Intermediate 2 obtained by the above operation is dissolved in 260 ml of toluene, and under a nitrogen atmosphere, 20 g of potassium carbonate, 120 ml of water, 22.5 g of 3,5-diphenyl-1-chlorotriazine, and 4.0 g of tetrakis (tri). Phenylphosphine) Palladium was added, and the mixture was stirred while heating at 70 ° C. for 7 hours.
The reaction mixture was allowed to cool to room temperature, the precipitated solid was collected by filtration, washed with water, and then washed with methanol. Further, it was recrystallized from toluene to obtain 19.0 g of Exemplified Compound 120.

<Use of aromatic heterocyclic derivatives>
The aromatic heterocyclic derivative having the structure represented by the general formula (1) according to the present invention can be used in a wide range of technical fields, but contains the aromatic heterocyclic derivative alone or a compound of another kind. Suitable as an organic functional material for electronic devices. For example, it can be suitably used in an organic electroluminescence element, a solar cell, a photoconductor for electrophotographic, and the like. In particular, it can be suitably used as a functional organic material in an organic electroluminescence device.

When used in an organic electroluminescence element, the light emitting layer preferably contains the aromatic heterocyclic derivative from the viewpoint of making more effective use of the characteristics of the aromatic heterocyclic derivative, and further, the light emitting layer contains the aromatic heterocyclic derivative. It is preferable to contain a group heterocyclic derivative as a host compound.

From the same viewpoint, it is preferable that the light emitting layer contains a phosphorescent dopant, and that the light emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative.

<< Constituent layer of organic electroluminescence device >>
Typical configurations of the organic functional layer and the like in the organic EL device of the present invention include, but are not limited to, the following configuration examples.
(1) anode / light emitting layer / cathode (2) anode / light emitting layer / electron transport layer / cathode (3) anode / hole transport layer / light emitting layer / cathode (4) anode / hole transport layer / light emitting layer / electron Transport layer / cathode (5) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (6) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode ( 7) Anophode / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron injection layer / cathode Among the above, the configuration of (7) is preferable. It is used, but is not limited to this.

The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.

If necessary, a hole blocking layer (also referred to as a hole barrier layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode, and the light emitting layer and the anode may be provided. An electron blocking layer (also referred to as an electron barrier layer) or a hole injection layer (also referred to as an anode buffer layer) may be provided between them.

The electron transport layer according to the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Further, it may be composed of a plurality of layers.

The hole transporting layer according to the present invention is a layer having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transporting layer. Further, it may be composed of a plurality of layers.

In the above typical device configuration, the layer excluding the anode and the cathode is also referred to as an "organic layer".

(Tandem structure)
Further, the organic EL element of the present invention may be an element having a so-called tandem structure in which a plurality of light emitting units including at least one light emitting layer are laminated.

As a typical element configuration of the tandem structure, for example, the following configuration can be mentioned.

Anode / 1st light emitting unit / 2nd light emitting unit / 3rd light emitting unit / cathode Anode / 1st light emitting unit / intermediate layer / 2nd light emitting unit / intermediate layer / 3rd light emitting unit / cathode Here, the first light emitting unit , The second light emitting unit and the third light emitting unit may all be the same or different. Further, the two light emitting units may be the same, and the remaining one may be different.

Further, the third light emitting unit may not be provided, while a light emitting unit or an intermediate layer may be further provided between the third light emitting unit and the electrode.

The plurality of light emitting units may be directly laminated or may be laminated via an intermediate layer, and the intermediate layer is generally an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, or an intermediate layer. A known material and structure can be used as long as it is also called an insulating layer and has a function of supplying electrons to the adjacent layer on the anode side and holes to the adjacent layer on the cathode side.

Examples of the material used for the intermediate layer include ITO (inorganic tin oxide), IZO (inorganic zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, and CuAlO _2. , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO ₂ , Al and other conductive inorganic compound layers, Au / Bi ₂ O _{3 and} other bilayer films, SnO ₂ / Ag / SnO ₂ , ZnO / Ag / _{ZnO, Bi 2 O 3 / Au} / Bi 2 O 3, TiO 2 / TiN / TiO 2, TiO 2 / ZrN / TiO 2 or the like multilayer film, also fullerenes such as _{C 60,} conductive organic material layer such as oligothiophene , Metallic phthalocyanines, metal-free phthalocyanines, metal porphyrins, conductive organic compound layers such as metal-free porphyrins, etc., but the present invention is not limited thereto.

Preferred configurations in the light emitting unit include, for example, configurations in which the anode and the cathode are removed from the configurations (1) to (7) mentioned in the above typical element configurations, but the present invention is limited thereto. Not done.

Specific examples of the tandem organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, and US Pat. No. 6,107,734. Specification, US Pat. No. 6,337,492, International Publication No. 2005/09087, JP-A-2006-228712, JP-A-2006-24791, JP-A-2006-49393, JP-A-2006-49394. , Japanese Patent Application Laid-Open No. 2006-49396, Japanese Patent Application Laid-Open No. 2011-96679, Japanese Patent Application Laid-Open No. 2005-340187, Japanese Patent No. 4711424, Japanese Patent No. 3496681, Japanese Patent No. 3884564, Japanese Patent No. 4213169, Japanese Patent Application Laid-Open No. 2010-192719 No., Japanese Patent Application Laid-Open No. 2009-0762929, Japanese Patent Application Laid-Open No. 2008-0784414, Japanese Patent Application Laid-Open No. 2007-059848, Japanese Patent Application Laid-Open No. 2003-272860, Japanese Patent Application Laid-Open No. 2003-045676, International Publication No. 2005/094130 The present invention is not limited thereto, although examples thereof include the element configurations and constituent materials described in the above.

Hereinafter, each layer constituting the organic EL device of the present invention will be described.

《Light emitting layer》
The light emitting layer used in the present invention is a layer that provides a place where electrons and holes injected from an electrode or an adjacent layer are recombined and emit light via excitons, and the light emitting portion is a light emitting layer. It may be in the layer or at the interface between the light emitting layer and the adjacent layer. The structure of the light emitting layer used in the present invention is not particularly limited as long as it satisfies the requirements specified in the present invention.

The total thickness of the light emitting layer is not particularly limited, but the homogeneity of the film to be formed, the prevention of applying an unnecessary high voltage at the time of light emission, and the improvement of the stability of the emission color with respect to the drive current are improved. From the viewpoint, it is preferably adjusted to the range of 2 nm to 5 μm, more preferably to the range of 2 to 500 nm, and further preferably to the range of 5 to 200 nm.

Further, in the present invention, the layer thickness of each light emitting layer is preferably adjusted in the range of 2 nm to 1 μm, more preferably in the range of 2 to 200 nm, and further preferably in the range of 3 to 150 nm. To.

The light emitting layer used in the present invention preferably contains a light emitting dopant (also simply referred to as a dopant) and a host compound (light emitting host, also simply referred to as "host").

(1) Phosphorescent Dopant As the light emitting dopant, a phosphorescent dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) and a fluorescent dopant (also referred to as a fluorescent dopant or a fluorescent compound) are preferably used. In the present invention, it is preferable that at least one light emitting layer contains a phosphorescent dopant.

The concentration of the light emitting dopant in the light emitting layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration with respect to the layer thickness direction of the light emitting layer. It may have an arbitrary concentration distribution.

Further, as the light emitting dopant used in the present invention, a plurality of types may be used in combination, a combination of dopants having different structures, or a combination of a fluorescent light emitting dopant and a phosphorescent light emitting dopant may be used. Thereby, an arbitrary emission color can be obtained.

The emission colors of the organic EL element of the present invention and the compound of the present invention are described in FIG. 4.16 on page 108 of the "New Color Science Handbook" (edited by the Japan Color Society, Tokyo University Press, 1985). It is determined by the color when the result measured by CS-1000 (manufactured by Konica Minolta Co., Ltd.) is applied to the CIE chromaticity coordinates.

In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting dopants having different light emitting colors and exhibits white light emission.

The combination of luminescent dopants showing white color is not particularly limited, and examples thereof include a combination of blue and orange, a combination of blue and green and red, and the like.

The white color in the organic EL element of the present invention is not particularly limited and may be white color closer to orange or white color closer to blue, but when the 2 degree viewing angle front luminance is measured by the above method. , It is preferable that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is within the region of x = 0.39 ± 0.09 and y = 0.38 ± 0.08.

(1.1) Phosphorescent Dopant A phosphorescent dopant used in the present invention (hereinafter, also referred to as “phosphorescent dopant”) will be described.

The phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescent light at room temperature (25 ° C.), and has a phosphorescent quantum yield. It is defined as a compound of 0.01 or more at 25 ° C., but a preferable phosphorescence quantum yield is 0.1 or more.

The phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th edition Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescence dopant used in the present invention achieves the above phosphorescence quantum yield (0.01 or more) in any of any solvents. Just do it.

There are two types of light emission of the phosphorescent dopant in principle. One is that carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. It is an energy transfer type that obtains light emission from a phosphorescent dopant. The other is a carrier trap type in which the phosphorescent dopant serves as a carrier trap, and carriers are recombined on the phosphorescent dopant to obtain light emission from the phosphorescent dopant. In either case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

As the phosphorescent dopant that can be used in the present invention, it can be appropriately selected from known ones used for the light emitting layer of the organic EL element.

Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

Nature 395, 151 (1998), Apple. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19,739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17,1059 (2005), International Publication No. 2009/10991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Publication No. 2006/835469, US Patent Application Publication No. 2006/20202194 No., US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, Inorg. Chem. 40,1704 (2001), Chem. Mater. 16,2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Apple. Phys. Lett. 86,153505 (2005), Chem. Lett. 34,592 (2005), Chem. Common. 2906 (2005), Inorg. Chem. 42,1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Application Publication No. 2002/0034656, US Patent No. 7332232 , US Patent Application Publication No. 2009/01087737, US Patent Application Publication No. 2009/00397776, US Patent Application Publication No. 6921915, US Patent No. 6687266, US Patent Application Publication No. 2007/0190359. , US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/015846, US Patent Application Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598 Specification, US Patent Application Publication No. 2006/0263635, US Patent Application Publication No. 2003/0138657, US Patent Application Publication No. 2003/0152802, US Patent No. 70090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18,5119 (2006), Inorg. Chem. 46,4308 (2007), Organometallics 23,3745 (2004), Apple. Phys. Lett. 74,1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/090024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Application Publication No. 2006/0251923, US Patent Application Publication No. 2005/02060441, US Patent No. 73935999 Specification, US Patent No. 7534505, US Patent No. 7445855, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2008/0297033, US Patent No. 7338722. , US Patent Application Publication No. 2002/0134984, US Patent No. 7279704, US Patent Application Publication No. 2006/098120, US Patent Application Publication No. 2006/103874, International Publication No. 2005 / 07680, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/05/2431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089 , International Publication No. 2009/113646, International Publication No. 2012/20327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228583 Specification, US Patent Application Publication No. 2012/212126, Japanese Patent Application Laid-Open No. 2012-069737, Japanese Patent Application Laid-Open No. 2012-195554, Japanese Patent Application Laid-Open No. 2009-114086, Japanese Patent Application Laid-Open No. 2003-81988, Japanese Patent Application Laid-Open No. 2002 −302671A, JP-A-2002-363552, and the like.

Among them, preferred phosphorescent dopants include organometallic complexes having Ir as the central metal. More preferably, a complex containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond is preferable.

(1.2) Fluorescent Luminescent Dopant A fluorescent luminescent dopant used in the present invention (hereinafter, also referred to as “fluorescent dopant”) will be described.

The fluorescent dopant used in the present invention is a compound capable of emitting light from the excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.

Examples of the fluorescent dopant used in the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluoranthene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes and coumarins. Examples thereof include derivatives, pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, and rare earth complex compounds.

Further, in recent years, light emitting dopants using delayed fluorescence have also been developed, and these may be used.

Specific examples of the light emitting dopant using delayed fluorescence include the compounds described in International Publication No. 2011/156793, Japanese Patent Application Laid-Open No. 2011-213643, Japanese Patent Application Laid-Open No. 2010-93181, and the like. Is not limited to these.

(2) Host Compound The host compound used in the present invention is a compound mainly responsible for charge injection and transport in the light emitting layer, and its own light emission is not substantially observed in the organic EL device.

A compound having a phosphorescent quantum yield of less than 0.1 at room temperature (25 ° C.) is preferable, and a compound having a phosphorescent quantum yield of less than 0.01 is more preferable. Further, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more.

Further, the excited state energy of the host compound is preferably higher than the excited state energy of the light emitting dopant contained in the same layer.

The host compound may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of electric charges, and it is possible to improve the efficiency of light emission of the organic EL element.

The host compound that can be used in the present invention is not particularly limited, and compounds conventionally used in organic EL devices can be used. It may be a low molecular weight compound, a high molecular weight compound having a repeating unit, or a compound having a reactive group such as a vinyl group or an epoxy group.

As a known host compound, it has hole transporting ability or electron transporting ability, prevents the wavelength of light emission from being lengthened, and further stabilizes the organic EL device against heat generation during high temperature driving or device driving. It is preferable to have a high glass transition temperature (Tg) from the viewpoint of operating the device. Tg is preferably 90 ° C. or higher, and more preferably 120 ° C. or higher.

Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry: differential scanning calorimetry).

Specific examples of the known host compound used in the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents.

JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787A, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002. 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 No. 3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-260861, No. 2002-280183, No. 2002-299060, No. 2002- 302516, 2002-305083, 2002-305084, 2002-308837, US Patent Application Publication No. 2003/0175553, US Patent Application Publication No. 2006/0280965, USA Publication of Patent Application Publication No. 2005/0112407, Publication of US Patent Application Publication No. 2009/0017330, Publication of US Patent Application Publication No. 2009/0030202, Publication of US Patent Application Publication No. 2005/0238919, International Publication No. 2001/039234, International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/0637996, International Publication No. 2007 / 063754, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/0293947 , Japanese Patent Application Laid-Open No. 2008-074939, Japanese Patent Application Laid-Open No. 2007-254297, European Patent No. 2034538, and the like.

《Electron transport layer》
In the present invention, the electron transport layer may be made of a material having a function of transporting electrons and may have a function of transmitting electrons injected from the cathode to the light emitting layer.

The total thickness of the electron transport layer used in the present invention is not particularly limited, but is usually in the range of 2 nm to 5 μm, more preferably 2 to 500 nm, and further preferably 5 to 200 nm.

Further, in the organic EL element, when the light generated in the light emitting layer is taken out from the electrode, the light taken out directly from the light emitting layer and the light taken out after being reflected by the electrode located at the opposite electrode to the electrode that takes out the light interfere with each other. It is known to wake up. When light is reflected by the cathode, this interference effect can be efficiently utilized by appropriately adjusting the total thickness of the electron transport layer between 5 nm and 1 μm.

On the other hand, if the layer thickness of the electron transport layer is increased, the voltage tends to increase. Therefore, especially when the layer thickness is thick, the electron mobility of the electron transport layer is preferably ^10-5 cm ² / Vs or more. ..

The material used for the electron transport layer (hereinafter referred to as an electron transport material) may have any of electron injectability, transportability, and hole barrier property, and is arbitrary from conventionally known compounds. Can be selected and used.

For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more of the carbon atoms constituting the carbazole ring substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, Triazine derivative, quinoline derivative, quinoxalin derivative, phenanthroline derivative, azatriphenylene derivative, oxazole derivative, thiazole derivative, oxadiazole derivative, thiadiazol derivative, triazole derivative, benzimidazole derivative, benzoxazole derivative, benzthiazole derivative, etc.), dibenzofuran derivative, Examples thereof include dibenzothiophene derivatives, silol derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

Further, a metal complex having a quinolinol skeleton or a dibenzoquinolinol skeleton as a ligand, for example, tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-) Dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and metal complexes thereof. A metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga or Pb can also be used as an electron transport material.

In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like can also be preferably used as an electron transport material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si or n-type-SiC is used like the hole injection layer and the hole transport layer. Can also be used as an electron transport material.

Further, it is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

In the electron transport layer used in the present invention, the electron transport layer may be doped with a doping material as a guest material to form an electron transport layer having a high n property (electron rich). Examples of the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-2970776, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Mol. Apple. Phys. , 95, 5773 (2004) and the like.

Specific examples of known and preferable electron transporting materials used in the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents.

US Patent No. 6528187, US Patent No. 7230107, US Patent Application Publication No. 2005/0025993, US Patent Application Publication No. 2004/0036077, US Patent Application Publication No. 2009/0115316. Books, US Patent Application Publication No. 2009/0101870, US Patent Application Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/132805, Appl. Phys. Lett. 75, 4 (1999), Apple. Phys. Lett. 79,449 (2001), Apple. Phys. Lett. 81, 162 (2002), Apple. Phys. Lett. 81, 162 (2002), Apple. Phys. Lett. 79,156 (2001), US Patent No. 7964293, US Patent Application Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387 , International Publication No. 2006/067931, International Publication No. 2007/0865552, International Publication No. 2008/114690, International Publication No. 2009/0694242, International Publication No. 2009/066797, International Publication No. 2009/054253, International Publication No. 2011/086935, International Publication No. 2010/150593, International Publication No. 2010/047707, European Patent No. 2311826, JP-A-2010-251675, JP-A-2009-209133, JP-A-2009. -124114, 2008-277810, 2006-156445, 2005-340122, 2003-45662, 2003-31367, 2003-282270. No., International Publication No. 2012/11034, etc.

More preferable electron transporting materials in the present invention include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.

The electron transport material may be used alone or in combination of two or more.

《Hole blocking layer》
The hole blocking layer is a layer having a function of an electron transporting layer in a broad sense, and is preferably made of a material having a function of transporting electrons and a small ability to transport holes, and a hole while transporting electrons. It is possible to improve the recombination probability of electrons and holes by blocking the above.

In addition, the structure of the electron transport layer described above can be used as the hole blocking layer according to the present invention, if necessary.

The hole blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the cathode side of the light emitting layer.

The layer thickness of the hole blocking layer used in the present invention is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

As the material used for the hole blocking layer, the material used for the electron transport layer described above is preferably used, and the material used as the host compound described above is also preferably used for the hole blocking layer.

《Electron injection layer》
The electron injection layer (also referred to as "cathode buffer layer") used in the present invention is a layer provided between the cathode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and is an "organic EL element". It is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "The Forefront of Industrialization (published by NTS Co., Ltd. on November 30, 1998)".

In the present invention, the electron injection layer may be provided as needed and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.

The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Further, it may be a non-uniform film in which the constituent material is intermittently present.

The details of the electron-injected layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specific examples of materials preferably used for the electron-injected layer include , Metals such as strontium and aluminum, alkali metal compounds such as lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compounds such as magnesium fluoride and calcium fluoride, oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by lithium 8-hydroxyquinolate (Liq) and the like. It is also possible to use the above-mentioned electron transport material.

Further, the material used for the above-mentioned electron injection layer may be used alone or in combination of two or more.

《Hole transport layer》
In the present invention, the hole transport layer may be made of a material having a function of transporting holes and may have a function of transmitting holes injected from the anode to the light emitting layer.

The total thickness of the hole transport layer used in the present invention is not particularly limited, but is usually in the range of 5 nm to 5 μm, more preferably 2 to 500 nm, and further preferably 5 nm to 200 nm.

The material used for the hole transport layer (hereinafter referred to as the hole transport material) may have any of hole injectability, transportability, and electron barrier property, and is among conventionally known compounds. Any one can be selected and used from.

For example, porphyrin derivative, phthalocyanine derivative, oxazole derivative, oxaziazole derivative, triazole derivative, imidazole derivative, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, hydrazone derivative, stilben derivative, polyarylalkane derivative, triarylamine derivative, carbazole derivative. , Indolocarbazole derivative, isoindole derivative, acene derivative such as anthracene and naphthalene, fluorene derivative, fluorenone derivative, polyvinylcarbazole, polymer material or oligomer in which aromatic amine is introduced into the main chain or side chain, polysilane, conductivity Examples thereof include sex polymers or oligomers (eg, PEDOT: PSS, aniline-based copolymers, polyaniline, polythiophene, etc.).

Examples of the triarylamine derivative include a benzidine type typified by αNPD, a starburst type typified by MTDATA, and a compound having fluorene or anthracene in the triarylamine connecting core portion.

Hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.

Further, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175. Apple. Phys. , 95, 5773 (2004) and the like.

In addition, JP-A-11-251667, J. Am. Hung et. al. So-called p-type hole transporting materials and inorganic compounds such as p-type-Si and p-type-SiC as described in the authored literature (Applied Physics Letters 80 (2002), p.139) can also be used. Further, an orthometalated organometallic complex having Ir or Pt in the central metal as represented by Ir (ppy) ₃ is also preferably used.

As the hole transport material, the above-mentioned materials can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organic metal complex, and an aromatic amine are introduced into the main chain or the side chain. High molecular weight materials or oligomers are preferably used.

Specific examples of known and preferable hole transporting materials used in the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents in addition to the documents mentioned above.

For example, Apple. Phys. Lett. 69,2160 (1996), J. Mol. Lumin. 72-74,985 (1997), Apple. Phys. Lett. 78,673 (2001), Apple. Phys. Lett. 90,183503 (2007), Apple. Phys. Lett. 90,183503 (2007), Apple. Phys. Lett. 51,913 (1987), Synth. Met. 87,171 (1997), Synth. Met. 91,209 (1997), Synth. Met. 111,421 (2000), SID Symposium Digital, 37,923 (2006), J. Mol. Mater. Chem. 3,319 (1993), Adv. Mater. 6,677 (1994), Chem. Mater. 15, 3148 (2003), US Patent Application Publication No. 2003/0162053, US Patent Application Publication No. 2002/0158242, US Patent Application Publication No. 2006/0240279, US Patent Application Publication No. 2008 / 0220265, US Patent No. 5061569, International Publication No. 2007/002683, International Publication No. 2009/01809, European Patent No. 650955, US Patent Application Publication No. 2008/01245772, US Patent Application Publication No. 2007/0278938, US Patent Application Publication No. 2008/0106190, US Patent Application Publication No. 2008/0018221, International Publication No. 2012/115034, Japanese Patent Application Laid-Open No. 2003-591432, No. 2006-135145, US Patent Application No. 13/585981, etc.

The hole transporting material may be used alone or in combination of two or more.

《Electronic blocking layer》
The electron blocking layer is a layer having a function of a hole transport layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, and is composed of a material having a small ability to transport electrons while transporting holes. It is possible to improve the recombination probability of electrons and holes by blocking the above.

Further, the structure of the hole transport layer described above can be used as an electron blocking layer used in the present invention, if necessary.

The electron blocking layer provided in the organic EL element of the present invention is preferably provided adjacent to the anode side of the light emitting layer.

The layer thickness of the electron blocking layer used in the present invention is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

As the material used for the electron blocking layer, the material used for the hole transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the electron blocking layer.

《Hole injection layer》
The hole injection layer (also referred to as “anode buffer layer”) used in the present invention is a layer provided between the anode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and is an “organic EL element”. And its industrialization forefront (published by NTS, Inc. on November 30, 1998), Volume 2, Chapter 2, "Electrode Materials" (pages 123-166).

In the present invention, the hole injection layer may be provided as needed and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.

The details of the hole injection layer are also described in JP-A-9-45479, 9-2660062, 8-288609, etc., and examples of the material used for the hole injection layer include. Examples thereof include materials used for the hole transport layer described above.

Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon. , Polyaniline (emeraldine), polythiophene and other conductive polymers, tris (2-phenylpyridine) iridium complexes and the like, orthometallated complexes, triarylamine derivatives and the like are preferable.

The material used for the hole injection layer described above may be used alone or in combination of two or more.

<< Other additives >>
The organic layer in the present invention described above may further contain other additives.

Examples of the additive include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals and alkaline earth metals such as Pd, Ca and Na, compounds and complexes of transition metals, salts and the like.

The content of the additive can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 50 ppm or less, based on the total mass% of the contained layer. ..

However, it is not within this range depending on the purpose of improving the transportability of electrons and holes, the purpose of favoring the energy transfer of excitons, and the like.

<< Method of forming organic layer >>
A method for forming an organic layer (hole injection layer, hole transport layer, electron blocking layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) used in the present invention will be described.

The method for forming the organic layer used in the present invention is not particularly limited, and conventionally known methods such as a vacuum vapor deposition method and a wet method (also referred to as a wet process) can be used. Here, it is preferable that the organic layer is a layer formed by a wet process. That is, it is preferable to manufacture an organic EL device by a wet process. By manufacturing the organic EL element by a wet process, it is possible to obtain an effect that a homogeneous film (coating film) is easily obtained and pinholes are less likely to be generated. The film (coating film) here is in a state of being dried after being applied by a wet process.

Examples of the wet method include a spin coating method, a casting method, an inkjet method, a printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, a curtain coating method, and an LB method (Langmuir-Brojet method). From the viewpoint of easy acquisition of a homogeneous thin film and high productivity, a method highly suitable for a roll-to-roll method such as a die coating method, a roll coating method, an inkjet method, or a spray coating method is preferable.

Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene and mesitylene. , Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO can be used.

Further, as a dispersion method, dispersion can be performed by a dispersion method such as ultrasonic waves, high shear force dispersion, or media dispersion.

Further, a different film forming method may be applied to each layer. When employing the vapor deposition film, the depositing conditions thereof are varied according to kinds of materials used, generally boat temperature 50 to 450 ° C., vacuum of ¹⁰ -6 ^{to 10} -2 Pa, deposition rate 0.01 It is desirable to appropriately select in the range of 50 nm / sec, substrate temperature -50 to 300 ° C., thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.

The organic layer used in the present invention is preferably formed from the hole injection layer to the cathode by one vacuuming, but it may be taken out in the middle and a different film forming method may be applied. In that case, it is preferable to carry out the work in a dry inert gas atmosphere.

"anode"
As the anode in the organic EL element, a metal, an alloy, an electrically conductive compound having a large work function (4 eV or more, preferably 4.5 V or more) and a mixture thereof as an electrode material are preferably used. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Further, a material such as IDIXO (In ₂ O _3- ZnO) that is amorphous and can produce a transparent conductive film may be used.

For the anode, a thin film may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 μm or more). The pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.

Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can also be used. When light emission is taken out from this anode, it is desirable to increase the transmittance to more than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less.

The thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

"cathode"
As the cathode, a metal having a small work function (4 eV or less) (referred to as an electron-injectable metal), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O). ₃ ) Examples thereof include a mixture, indium, a lithium / aluminum mixture, aluminum, and a rare earth metal. Among these, from the viewpoint of electron injectability and durability against oxidation and the like, a mixture of an electron injectable metal and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture. Magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium / aluminum mixture, aluminum and the like are suitable.

The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance of the cathode is preferably several hundred Ω / □ or less, and the thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

In order to transmit the emitted light, it is convenient that the emission brightness is improved if either the anode or the cathode of the organic EL element is transparent or translucent.

Further, a transparent or translucent cathode can be produced by producing the above metal on the cathode having a thickness of 1 to 20 nm and then producing the conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture an element in which both the anode and the cathode are transparent.

《Support board》
The type of support substrate (hereinafter, also referred to as substrate, substrate, substrate, support, etc.) that can be used for the organic EL element of the present invention is not particularly limited in the types such as glass and plastic, and is transparent. May also be opaque. When light is taken out from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of imparting flexibility to the organic EL element.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate. CAP), cellulose acetate phthalate, cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyether sulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic, or polyarylates, Arton (trade name: JSR) or Cycloolefin resins such as Apel (trade name: manufactured by Mitsui Chemicals, Inc.) can be mentioned.

A film of an inorganic substance, an organic substance, or a hybrid film of both of them may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. oxygen relative humidity (90 ± 2)% RH) is preferably a barrier film of 0.01g ^/ (m 2 · 24h) or less, and still more, as measured by the method based on JIS K 7126-1987 the ^{permeability, 10 -3 ml / (m 2} · 24h · atm) or less, the water vapor permeability ^is preferably ^{10 -5 g / (m 2 ·} 24h) or less of the high barrier film.

As the material for forming the barrier film, any material that causes deterioration of the element such as water and oxygen but has a function of suppressing infiltration may be used, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The stacking order of the inorganic layer and the organic layer is not particularly limited, but it is preferable to stack the inorganic layer and the organic layer alternately a plurality of times.

The method for forming the barrier film is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method. , Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used, but the atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

Examples of the opaque support substrate include a metal plate such as aluminum and stainless steel, a film or opaque resin substrate, and a ceramic substrate.

The external extraction quantum efficiency of the light emission of the organic EL device of the present invention at room temperature is preferably 1% or more, more preferably 5% or more.

Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons passed through the organic EL element × 100.

Further, a hue improving filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor may be used in combination.

《Seal》
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of adhering a sealing member, an electrode, and a support substrate with an adhesive. The sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.

Specific examples of the sealing member include a glass plate, a polymer plate, and a metal plate. 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. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.

In the present invention, a polymer film or a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film JIS K 7126-1987 oxygen permeability measured by the method conforming to the ^{1 × 10 -3 ml / (m} 2 · 24h · atm) or less, by a method according to JIS K 7129-1992 the measured water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably that of ^{1 × 10 -3 g / (m} 2 · 24h) or less.

Sandblasting, chemical etching, etc. are used to process the sealing member into a concave shape.

Specific examples of the adhesive include a photocurable and thermosetting adhesive having a reactive vinyl group of an acrylic acid-based oligomer, a moisture-curable adhesive such as 2-cyanoacrylic acid ester, and the like. be able to. In addition, heat and chemical curing type (two-component mixture) such as epoxy type can be mentioned. Further, hot melt type polyamide, polyester and polyolefin can be mentioned. In addition, a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.

Since the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing may be performed as in screen printing.

Further, it is also possible to preferably coat the electrode and the organic layer on the outside of the electrode on the side facing the support substrate with the organic layer sandwiched therein, and form a layer of an inorganic substance or an organic substance in contact with the support substrate to form a sealing film. .. In this case, the material for forming the film may be any material having a function of suppressing infiltration of a material that causes deterioration of the element such as water and oxygen, and for example, silicon oxide, silicon dioxide, silicon nitride or the like may be used. it can.

Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The method for forming these films is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight. Legal, plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used.

In the gas phase and liquid phase, an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicon oil may be injected into the gap between the sealing member and the display region of the organic EL element. preferable. It is also possible to create a vacuum. It is also possible to enclose a hygroscopic compound inside.

Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (eg, perchloric acid) (Valium, magnesium perchlorate, etc.) and the like, and anhydrous salts are preferably used for sulfates, metal halides and perchlorates.

《Protective film, protective plate》
A protective film or protective plate may be provided on the outer side of the sealing film or the sealing film on the side facing the support substrate with the organic layer sandwiched in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, its mechanical strength is not necessarily high, so it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, a glass plate, a polymer plate, a metal plate, etc. similar to those used for the sealing can be used, but a polymer film can be used because it is lightweight and thin. preferable.

<< Technology for improving light extraction >>
The organic electroluminescence element emits light inside a layer having a higher refractive index than air (within a refractive index of about 1.6 to 2.1), and about 15% to 20% of the light generated in the light emitting layer. It is generally said that only light can be extracted. This is because light incident on the interface (intersection between the transparent substrate and air) at an angle θ equal to or greater than the critical angle causes total internal reflection and cannot be taken out of the element, and the transparent electrode or light emitting layer and the transparent substrate This is because the light is totally reflected between them, the light is waveguideed through the transparent electrode or the light emitting layer, and as a result, the light escapes toward the side surface of the element.

As a method for improving the efficiency of light extraction, for example, a method of forming irregularities on the surface of a transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (for example, US Pat. No. 4,774,435), the substrate A method of improving efficiency by providing light-collecting property (for example, Japanese Patent Application Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (for example, Japanese Patent Application Laid-Open No. 1-220394), a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the light emitting body and the light emitting body (for example, Japanese Patent Application Laid-Open No. 62-172691), which has a lower refractive index than the substrate between the substrate and the light emitting body. A method of introducing a flat layer having a refractive index (for example, Japanese Patent Application Laid-Open No. 2001-202827), a method of forming a diffraction grating between layers of a substrate, a transparent electrode layer or a light emitting layer (including between the substrate and the outside world) ( JP-A-11-283751) and the like.

In the present invention, these methods can be used in combination with the organic EL element of the present invention, but a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or the substrate, transparent. A method of forming a diffraction grating between layers (including between the substrate and the outside world) of either the electrode layer or the light emitting layer can be preferably used.

In the present invention, by combining these means, it is possible to obtain an element having higher brightness or excellent durability.

When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light emitted from the transparent electrode has a higher efficiency of being taken out to the outside as the refractive index of the medium is lower. Become.

Examples of the low refractive index layer include airgel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, it is preferable that the low refractive index layer has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

Further, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because the effect of the low-refractive-index layer diminishes when the thickness of the low-refractive-index medium becomes about the wavelength of light and the layer thickness at which the electromagnetic waves exuded by evanescent penetrate into the substrate.

The method of introducing the diffraction grating into the interface where total reflection occurs or any medium is characterized in that the effect of improving the light extraction efficiency is high. This method is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from the refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction. Of the generated light, the light that cannot go out due to total reflection between the layers is diffracted by introducing a diffraction grating between either layer or in the medium (inside the transparent substrate or in the transparent electrode). , Trying to get the light out.

It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because the light emitted by the light emitting layer is randomly generated in all directions, so a general one-dimensional diffraction grating that has a periodic refractive index distribution only in one direction diffracts only the light that travels in a specific direction. The light extraction efficiency does not increase so much.

However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency is improved.

The position where the diffraction grating is introduced may be in any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but it is desirable that the diffraction grating is introduced in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of the light in the medium. It is preferable that the arrangement of the diffraction grating is two-dimensionally repeated, such as a square lattice shape, a triangular lattice shape, and a honeycomb lattice shape.

《Condensing sheet》
The organic EL element of the present invention can be processed in a specific direction by, for example, processing so as to provide a structure on a microlens array on the light extraction side of a support substrate (substrate) or by combining with a so-called condensing sheet. For example, the brightness in a specific direction can be increased by condensing light in the front direction with respect to the light emitting surface of the element.

As an example of a microlens array, a quadrangular pyramid having a side of 30 μm and an apex angle of 90 degrees is arranged two-dimensionally on the light extraction side of the substrate. One side is preferably in the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction occurs and it is colored, and if it is too large, the thickness becomes thick, which is not preferable.

As the condensing sheet, for example, a sheet that has been put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness increasing film (BEF) manufactured by Sumitomo 3M Ltd. can be used. The shape of the prism sheet may be, for example, a base material having a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or a shape having a rounded apex angle and a random pitch change. Shape or other shape may be used.

Further, the light diffusing plate / film may be used in combination with the condensing sheet in order to control the light emission angle from the organic EL element. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Applications of organic EL elements >>
The organic EL element of the present invention can be used as a display device, a display, and various light emitting light sources.

Light sources include, for example, lighting devices (household lighting, interior lighting), clock and liquid crystal backlights, signage advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light. Examples thereof include a light source of a sensor, but the present invention is not limited to this, and the light source can be effectively used as a backlight of a liquid crystal display device or a light source for lighting.

In the organic EL device of the present invention, if necessary, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation. In the case of patterning, only the electrodes may be patterned, the electrodes and the light emitting layer may be patterned, or all the layers of the device may be patterned. In the fabrication of the device, a conventionally known method is used. Can be done.

《Display device》
An aspect of the display device of the present invention provided with the organic EL element of the present invention will be described. Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing an example of the configuration of a display device including the organic EL element of the present invention, and displays image information by emitting light from the organic EL element, for example, a display of a mobile phone or the like. It is a schematic diagram. As shown in FIG. 1, the display 1 includes a display unit A having a plurality of pixels, a control unit B that scans an image of the display unit A based on image information, and the like.

The control unit B is electrically connected to the display unit A. The control unit B sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. As a result, each pixel sequentially emits light according to the image data signal for each scanning line by the scanning signal, and the image information is displayed on the display unit A.

FIG. 2 is a schematic view of the display unit A shown in FIG.

The display unit A has a wiring unit including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 and the like on the substrate.

The main members of the display unit A will be described below.

FIG. 2 shows a case where the light emitted from the pixel 3 is taken out in the direction of the white arrow (downward). The scanning line 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material. The scanning line 5 and the data line 6 are orthogonal to each other in a grid pattern and are connected to the pixel 3 at the orthogonal positions (details are not shown).

When the scanning signal is transmitted from the scanning line 5, the pixel 3 receives the image data signal from the data line 6 and emits light according to the received image data.

Full-color display is possible by appropriately arranging pixels in the red region, pixels in the green region, and pixels in the blue region in parallel on the same substrate.

《Lighting device》
An aspect of the lighting device of the present invention provided with the organic EL element of the present invention will be described.

The non-light emitting surface of the organic EL element of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (Lux manufactured by Toa Synthetic Co., Ltd.) is used as a sealing material around the glass substrate. Track LC0629B) is applied, which is placed on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS. 3 and 4. The device can be formed.

FIG. 3 shows a schematic view of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (note that the sealing operation with the glass cover brings the organic EL element 101 into contact with the atmosphere. Do not use the glove box in a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas with a purity of 99.999% or higher).

FIG. 4 shows a cross-sectional view of the lighting device. In FIG. 4, 105 shows a cathode, 106 shows an organic EL layer, and 107 shows a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108, and a water catching agent 109 is provided.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in the examples, it represents "volume%" unless otherwise specified.

Further, the numbers of the host compounds used in the organic EL device of the present invention in Tables 1 to 4 are aromatic heterocyclic derivatives having the structure represented by the above general formula (1), that is, the general formula (1-). 1) Corresponds to the number of a specific example of the aromatic heterocyclic derivative having the structure represented by (1-16).

<< Compound used in Examples >>
The structural formulas of the compounds used in the examples are shown below. Incidentally. The comparative hosts 1 to 4 are the compounds described in U.S. Patent Application Publication No. 2015/0259221, Korean Patent Application Publication No. 2015-0031396, International Publication No. 2015/10251 and International Publication No. 2015/014434, respectively. Is.

[Example 1]
<< Fabrication of organic EL element >>
(1) Preparation of Organic EL Element 101 On a glass substrate having a thickness of 50 mm × 50 mm and a thickness of 0.7 mm, ITO (indium tin oxide) as an anode was formed into a film having a thickness of 150 nm, and after patterning, it was performed. The transparent substrate to which the ITO transparent electrode was attached was ultrasonically washed with isopropyl alcohol, dried with dry nitrogen gas, UV ozone washed for 5 minutes, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. ..

Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. The resistance heating boat was made of molybdenum or tungsten.

After depressurizing to a vacuum degree of 1 × 10 ^-4 Pa, a resistance heating boat containing HI-1 is energized and heated, and thin-film deposition is performed on an ITO transparent electrode at a vapor deposition rate of 0.1 nm / sec to a positive layer thickness of 15 nm. A hole injection layer was formed.

Next, HT-1 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a hole transport layer having a layer thickness of 30 nm.

Next, the resistance heating boat containing the comparison host 1 and the GD-1 was energized and heated, and co-deposited on the hole transport layer at a vapor deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively, to achieve a layer thickness. A 40 nm light emitting layer was formed.

Next, HB-1 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a first electron transport layer having a film thickness of 5 nm.

Further, ET-1 was vapor-deposited on it at a vapor deposition rate of 0.1 nm / sec to form a second electron transport layer having a layer thickness of 45 nm.

Then, after vapor-depositing lithium fluoride to a film thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode, thereby producing an organic EL element 101.

After production, the non-light emitting surface of the organic EL element 101 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a glass substrate having a thickness of 300 μm is used as a sealing substrate to surround the organic EL element 101. An epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) was applied as a sealing material, and this was placed on the cathode and brought into close contact with the transparent support substrate, and UV light was irradiated from the glass substrate side. It was cured and sealed to prepare an illuminating device having the configurations shown in FIGS. 3 and 4, and this was used as a sample.

<< Fabrication of organic EL elements 102 to 117 >>
In the preparation of the organic EL element 101, the host compound was changed to the compound shown in Table 1. Other than that, the organic EL elements 102 to 117 were manufactured in the same manner.

<< Evaluation of Organic EL Elements 101-117 >>
The following evaluation was performed for each sample. The evaluation results are shown in Table 1.

(1) External extraction Quantum efficiency The organic EL element is energized under constant current conditions of room temperature (25 ° C.) and 2.5 mA / cm ² , and the emission brightness (L0) [cd / m ² ] immediately after the start of emission is measured. By doing so, the external extraction quantum efficiency (η) was calculated.

Here, the emission brightness was measured using CS-2000 (manufactured by Konica Minolta Sensing), and the external extraction quantum efficiency was expressed as a relative value with the organic EL element 101 as 100.

It should be noted that the larger the value, the more efficient the comparison.

(2) Half-life The half-life was evaluated according to the measurement method shown below.

Each organic EL element was driven with a constant current with a current giving an initial brightness of 4000 cd / m ^2, and the time to be halved of the initial brightness was obtained, which was used as a measure of half life. The half-life was expressed as a relative value with the organic EL element 101 as 100.

The larger the value, the better the durability for comparison.

(3) Evaluation of stability at high temperature storage The organic EL element is placed in a constant temperature bath under high temperature conditions (about 50 ± 5 ° C.), and the half life is evaluated under the same conditions as the above (2) Half life measurement method. The heat resistance was calculated using.

Heat resistance (%) = (half life under high temperature conditions) / (half life at room temperature) x 100
Table 1 shows the relative values with the organic EL element 101 as 100. The larger the value of heat resistance, the higher the durability against temperature change.

From Table 1, the organic EL elements 105 to 117 of the present invention have higher luminous efficiency and longer emission life than the organic EL elements 101 to 104 of the comparative example, and the storage stability at high temperature is particularly improved. I understand.

[Example 2]
<< Fabrication of organic EL element >>
(1) Fabrication of Organic EL Element 201 On a glass substrate having a thickness of 50 mm × 50 mm and a thickness of 0.7 mm, ITO (indium tin oxide) as an anode was formed into a film having a thickness of 150 nm, and after patterning, it was performed. The transparent substrate to which the ITO transparent electrode was attached was ultrasonically washed with isopropyl alcohol, dried with dry nitrogen gas, UV ozone washed for 5 minutes, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. ..

Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. The resistance heating boat was made of molybdenum or tungsten.

After depressurizing to a vacuum degree of 1 × 10 ^-4 Pa, a resistance heating boat containing HI-2 is energized and heated, and thin-film deposition is performed on an ITO transparent electrode at a vapor deposition rate of 0.1 nm / sec to a positive layer thickness of 10 nm. A hole injection layer was formed.

Next, HT-2 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a hole transport layer having a film thickness of 30 nm.

Next, the resistance heating boat containing the comparison host 1 and the GD-2 was energized and heated, and co-deposited on the hole transport layer at a vapor deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively, to achieve a layer thickness. A light emitting layer of 30 nm was formed.

Next, HB-2 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a first electron transport layer having a layer thickness of 5 nm.

Further, ET-2 was vapor-deposited on it at a vapor deposition rate of 0.1 nm / sec to form a second electron transport layer having a layer thickness of 45 nm.

Then, after vapor-depositing lithium fluoride to a film thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode, thereby producing an organic EL element 201.

After production, the non-light emitting surface of the organic EL element 201 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a glass substrate having a thickness of 300 μm is used as a sealing substrate to surround the organic EL element 201. An epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) was applied as a sealing material, and this was placed on the cathode and brought into close contact with the transparent support substrate, and UV light was irradiated from the glass substrate side. It was cured and sealed to prepare an illuminating device having the configurations shown in FIGS. 3 and 4, and this was used as a sample.

<< Fabrication of organic EL elements 202 to 220 >>
In the production of the organic EL element 201, the host compound was changed to the host compound shown in Table 2. Other than that, the organic EL elements 202 to 220 were manufactured in the same manner.

<< Evaluation of organic EL elements 201-220 >>
The following evaluation was performed for each sample.

The external extraction quantum efficiency, half-life, and high-temperature storage stability evaluation were evaluated by the same method as in Example 1, and expressed as relative values with each characteristic value of the organic EL element 201 as 100.

The evaluation results are shown in Table 2.

From Table 2, the organic EL element of the present invention has high luminous efficiency to the organic EL elements 201 to 204 of the comparative example, the emission lifetime is long, it can be seen that in particular improved storage stability at high temperature ..

[Example 3]
<< Fabrication of organic EL element >>
(1) Preparation of Organic EL Element 301 A glass substrate having a thickness of 50 mm × 50 mm and a thickness of 0.7 mm is formed with ITO (indium tin oxide) as an anode to a thickness of 150 nm, and after patterning, the organic EL element 301 is formed. The transparent substrate to which the ITO transparent electrode was attached was ultrasonically washed with isopropyl alcohol, dried with dry nitrogen gas, UV ozone washed for 5 minutes, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. ..

Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. The resistance heating boat was made of molybdenum or tungsten.

After depressurizing to a vacuum degree of 1 × 10 ^-4 Pa, a resistance heating boat containing HI-2 is energized and heated, and thin-film deposition is performed on an ITO transparent electrode at a vapor deposition rate of 0.1 nm / sec to a positive layer thickness of 20 nm. A hole injection layer was formed.

Next, HT-1 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a hole transport layer having a layer thickness of 20 nm.

Next, the resistance heating boat containing the comparison host 1 and the GD-3 was energized and heated, and co-deposited on the hole transport layer at a vapor deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively, to achieve a layer thickness. A light emitting layer of 30 nm was formed.

Next, HB-3 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form a first electron transport layer having a layer thickness of 10 nm.

Further, ET-2 was vapor-deposited on it at a vapor deposition rate of 0.1 nm / sec to form a second electron transport layer having a layer thickness of 40 nm.

Then, after vapor-depositing lithium fluoride to a layer thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode, thereby producing an organic EL element 301.

After production, the non-light emitting surface of the organic EL element 301 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a glass substrate having a thickness of 300 μm is used as a sealing substrate to surround the organic EL element 301. An epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) was applied as a sealing material, and this was placed on the cathode and brought into close contact with the transparent support substrate, and UV light was irradiated from the glass substrate side. It was cured and sealed to prepare an illuminating device having the configurations shown in FIGS. 3 and 4, and this was used as a sample.

<< Fabrication of organic EL elements 302 to 315 >>
In the preparation of the organic EL element 301, the host compound was changed to the host compound shown in Table 3. Other than that, the organic EL elements 302 to 315 were manufactured in the same manner.

<< Evaluation of organic EL elements 301 to 314 >>
The following evaluation was performed for each sample.

The external extraction quantum efficiency, half-life, and high-temperature storage stability evaluation were evaluated by the same method as in Example 1, and expressed as relative values with each characteristic value of the organic EL element 301 as 100.

The evaluation results are shown in Table 3.

From Table 3, the organic EL elements 305 to 315 of the present invention have higher luminous efficiency and longer emission life than the organic EL elements 301 to 304 of the comparative example, and the storage stability at high temperature is particularly improved. I understand.

[Example 4]
<< Fabrication of organic EL element >>
(1) Fabrication of Organic EL Element 401 On a glass substrate having a thickness of 50 mm × 50 mm and a thickness of 0.7 mm, ITO (indium tin oxide) as an anode is formed into a film having a thickness of 120 nm, and after patterning, this is performed. The transparent substrate to which the ITO transparent electrode was attached was ultrasonically washed with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone washed for 5 minutes.

A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) diluted to 70% with pure water was used on this transparent support substrate at 3000 rpm. A thin film was formed by a spin coating method under the condition of 30 seconds, and then dried at 200 ° C. for 1 hour to provide a hole injection layer having a layer thickness of 20 nm.

Next, this transparent substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.

Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. The resistance heating boat for vapor deposition was made of molybdenum or tungsten.

After depressurizing to a vacuum degree of 1 × 10 ^-4 Pa, the resistance heating boat containing HT-2 is energized and heated, and thin-film deposition is performed on the hole injection layer at a vapor deposition rate of 0.1 nm / sec to a layer thickness of 20 nm. A hole transport layer was formed.

Next, the resistance heating boat containing the comparison host 1 and the GD-1 was energized and heated, and co-deposited on the hole transport layer at a vapor deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively, to achieve a layer thickness. A 40 nm light emitting layer was formed.

Next, ET-1 was vapor-deposited at a vapor deposition rate of 0.1 nm / sec to form an electron transport layer having a layer thickness of 40 nm.

After vapor-depositing lithium fluoride to a layer thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode, thereby producing an organic EL element 401.

After production, the non-emission surface of the organic EL element 401 is covered with a glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and a glass substrate having a thickness of 300 μm is used as a sealing substrate to surround the organic EL element 401. An epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) was applied as a sealing material, and this was placed on the cathode and brought into close contact with the transparent support substrate, and UV light was irradiated from the glass substrate side. It was cured and sealed to prepare an illuminating device having the configurations shown in FIGS. 3 and 4, and this was used as a sample.

<< Fabrication of organic EL elements 402 to 425 >>
In the production of the organic EL element 401, the host compound was changed to the host compound shown in Table 4. Other than that, the organic EL elements 402 to 425 were manufactured in the same manner.

<< Evaluation of organic EL elements 401 to 425 >>
The following evaluation was performed for each sample.

The external extraction quantum efficiency, half-life, and high-temperature storage stability evaluation were evaluated by the same method as in Example 1, and expressed as relative values with each characteristic value of the organic EL element 401 as 100.

The evaluation results are shown in Table 4.

From Table 4, the organic EL element of the present invention has high luminous efficiency to the organic EL elements 401 to 404 of the comparative example, the emission lifetime is long, it can be seen that in particular improved storage stability at high temperature ..

[ Reference Example 5]
<< Manufacturing of full-color display device >>
(1) Fabrication of blue light emitting element << Fabrication of organic EL element 501 >>
After patterning on a 100 mm × 100 mm × 1.1 mm glass substrate with an ITO (indium tin oxide) film having a thickness of 100 nm as an anode (NA45 manufactured by NH Technoglass Co., Ltd.), this ITO transparent electrode The transparent support substrate provided with the above was ultrasonically washed with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone washed for 5 minutes.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus, while 200 mg of HT-3 is placed in a molybdenum resistance heating boat, and mCP (1,3-) is used as a host compound in another molybdenum resistance heating boat. 200 mg of bis-N carbazolylbenzene), 200 mg of HB-4 in another molybdenum resistance heating boat, 100 mg of BD-1 as a light emitting dopant in another molybdenum resistance heating boat, and another molybdenum product. 200 mg of ET-2 was placed in a resistance heating boat and attached to a vacuum vapor deposition apparatus.

Next, after depressurizing the vacuum chamber to 4 × 10 ^-4 Pa, the molybdenum resistance heating boat containing HT-3 is energized and heated, and vapor deposition is performed on a transparent support substrate at a vapor deposition rate of 0.1 nm / sec. Then, a hole transport layer having a layer thickness of 40 nm was provided.

Further, the molybdenum resistance heating boat containing mCP (1,3-bis-N carbazolylbenzene) and BD-1 is energized and heated, and the deposition rates are 0.2 nm / sec and 0.012 nm / sec, respectively. Then, a light emitting layer having a thickness of 40 nm was provided by co-depositing on the hole transport layer. The substrate temperature during vapor deposition was room temperature.

Further, the molybdenum resistance heating boat containing HB-4 was energized and heated, and vapor deposition was performed on the light emitting layer at a vapor deposition rate of 0.1 nm / sec to provide a hole blocking layer having a thickness of 10 nm. ..

Further, the resistance heating boat containing ET-2 was energized and heated, and vapor deposition was performed on the hole blocking layer at a vapor deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 40 nm. The substrate temperature during vapor deposition was room temperature.

Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 501 was manufactured.

(2) Preparation of Green Light Emitting Element The organic EL element 419 of Example 4 was used as the green light emitting element.

(3) Fabrication of red light emitting element << Fabrication of organic EL element 502 >>
In the organic EL element 419 of Example 4, which is a green light emitting element, the light emitting dopant was changed from GD-1 to RD-1. Other than that, the organic EL element 502 which is a red light emitting element was manufactured in the same manner as the organic EL element 419 which is a green light emitting element.
(4) Production of Display Device The red, green, and blue light emitting organic EL elements produced above were arranged in parallel on the same substrate to produce an active matrix type full-color display device having a form as shown in FIG.

FIG. 2 shows only a schematic view of the display unit A of the manufactured display device.

As shown in FIG. 2, the display unit A has a plurality of pixels 3 (pixels whose emission colors are in the red region and pixels in the green region) arranged in parallel with a wiring unit including a plurality of scanning lines 5 and data lines 6 on the same substrate. It has pixels in the blue region, etc.). The scanning line 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material. The scanning line 5 and the data line 6 are orthogonal to each other in a grid pattern and are connected to the pixel 3 at orthogonal positions (details are not shown).

The plurality of pixels 3 are driven by an active matrix system in which an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor are provided, and a scanning signal is transmitted from the scanning line 5. And the image data signal is received from the data line 6, and light is emitted according to the received image data. A full-color display device was produced by appropriately arranging the red, green, and blue pixels 3 in parallel in this way.

It was confirmed that the obtained full-color display device can obtain a full-color moving image display having high brightness, high durability, and excellent storage stability at high temperature by driving.

1 Display 3 pixels 5 Scan line 6 Data line A Display unit B Control unit 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Transparent electrode exhausted glass substrate 108 Nitrogen gas 109 Water catching agent

Claims (12)

An organic electroluminescence element in which an organic functional layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one of the organic functional layers has a structure represented by the following general formula (1). An organic electroluminescence element containing an aromatic heterocyclic derivative.

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not bond with each other to form a ring, and do not form a ring with other parts in the general formula (1). X is an oxygen atom or a sulfur atom. However, compounds having a structure represented by the following general formulas (E1) to (E8) are excluded. )

(In the formula, X represents an oxygen atom or a sulfur atom.) The aromatic heterocyclic derivative having the structure represented by the general formula (1) has a structure represented by any of the structures represented by the following general formulas (1-1) to (1-16). The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device is provided.

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not combine with each other to form a ring, nor do they form a ring with other parts of the general formulas (1-1) to (1-16). X represents an oxygen atom or a sulfur atom. However, in each of the general formula (1-8), the general formula (1-14) and the general formula (1-16), R _{1 to} R ₅ are all hydrogen. Except for atoms.) The organic electroluminescence device according to claim 1 or 2, wherein each of the Ar ₁ and Ar ₂ represents a monocyclic aryl group. The organic electroluminescence device according to any one of claims 1 to 3, wherein each of R _{1 to} R ₅ represents a hydrogen atom. Any one of claims 1 to 4, wherein R _{1 to} R ₅ each represent a hydrogen atom, and Ar ₁ and Ar ₂ each represent a monocyclic aryl group. The organic electroluminescence device described in the section. The organic electroluminescence device according to any one of claims 1 to 5, wherein the light emitting layer contains the aromatic heterocyclic derivative. The organic electroluminescence device according to any one of claims 1 to 6, wherein the light emitting layer contains the aromatic heterocyclic derivative as a host compound. The organic electroluminescence device according to any one of claims 1 to 7, wherein the light emitting layer contains a phosphorescent dopant. The organic electroluminescence device according to any one of claims 1 to 8, wherein the light emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative. A display device comprising the organic electroluminescence device according to any one of claims 1 to 9. A lighting device comprising the organic electroluminescence device according to any one of claims 1 to 9. An organic functional material for an electronic device, which contains an aromatic heterocyclic derivative having a structure represented by the following general formula (1).

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, a cyano group or a fluorine atom. R _{1 to} R ₅ do not bond with each other to form a ring, and do not form a ring with other parts in the general formula (1). X is an oxygen atom or a sulfur atom. However, compounds having a structure represented by the following general formulas (E1) to (E8) are excluded. )

(In the formula, X represents an oxygen atom or a sulfur atom.)

Images