JP7196926B2 - Mixed composition for organic electroluminescence device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mixed composition for organic electroluminescent devices, and more particularly to a mixed composition for organic electroluminescent devices that can improve the solubility of a solute in a solvent.

2. Description of the Related Art A display, which is a video display unit for televisions, computers, etc., has become one of the indispensable electronic devices in modern society. In recent years, there has been a rapid increase in demand for larger displays and greater flexibility in installation, and along with this, the development of organic electroluminescence (hereinafter also referred to as organic EL) devices has been active.
Organic EL elements are self-luminous all-solid-state light-emitting elements that have a relatively simple structure and wide viewing angles. .

In recent years, in order to achieve cost reduction and mass production, which are longed for in the development of organic EL devices, we have replaced the vacuum deposition method, which was a high-energy-consuming process that used to be the mainstream for manufacturing, by applying solution coating and Attention has been focused on a process using a wet coating method (hereinafter also simply referred to as coating method) for forming a functional film by printing. Among them, the inkjet printing method is one of the most promising processes because it does not require a large-sized apparatus and can produce organic EL elements with high definition and arbitrary patterns.

However, in most cases, when the same molecule is used to form a film by a vacuum deposition method and a coating method, the film obtained by the coating method (hereinafter referred to as the coating film) is the same as the film obtained by the vacuum deposition method (hereinafter referred to as the deposited film). ) are known to have poor performance.
One of the factors for this is the low solubility of the solute, which is the compound used in the organic EL device, in the coating solvent. In general, many organic EL materials have molecules with a condensed ring structure consisting of aromatic rings, and these molecules form a dense stacking structure due to strong π-π interaction between molecules, which may make them poorly soluble in solvents. many. It is known that orthophenylpyridine derivatives, which are suitably used in the electron transport layer of organic EL devices in terms of performance, are also poorly soluble in common organic solvents.
In order to solve this problem of solubility, fluorinated alcohols substituted with fluorine atoms have conventionally been used as solvents (see Patent Documents 1 and 2). Fluorinated alcohol is also considered preferable because it does not dissolve the compound used in the light-emitting layer, which is the lower layer of the electron-transporting layer of the organic EL device. However, when a fluorinated alcohol is used as a solvent in an inkjet printing method, there remains the problem that the member of the head portion that ejects the solution is swollen and damaged.

JP-A-2002-216956 JP-A-2004-265672

The present invention has been made in view of the above problems and circumstances, and the problem to be solved is an organic electroluminescence device that can improve the solubility of a solute in a solvent and can be suitably used for inkjet printing. It is to provide a mixed composition for

The inventors of the present invention considered that, in order to expand the selectivity of solvents that can be used, it was first necessary to reconsider the phenomenon of dissolution of solutes in solvents. In the first place, the phenomenon of dissolution itself contains ambiguity, and in many cases, whether or not a solute is dissolved in a solvent can be visually judged by visual observation that the solution is transparent without cloudiness or aggregation. In most cases, the solute at this time is in the form of clusters of several molecules to several hundred molecules, and there is no problem when sugar or salt is added to beverages, but in the case of organic EL devices, aggregates It is important that the solute is completely dispersed in the solvent molecules at the molecular level, because the presence of has a significant adverse effect on the performance of the device.
A typical example of improving the solubility of a solute in a solvent is to introduce a bulky substituent such as an alkyl group to create steric hindrance. It may also impair the performance of the solute as an element material.
Therefore, the present inventors conducted extensive studies and found that the solubility of the solute is improved by using a solvent that forms a hydrogen bond with the solute, leading to the present invention.
That is, the above problems related to the present invention are solved by the following means.

［一般式（１）中、＝Ｎ－を含んで形成される環Ａ１は、２－ピリジン環を表す。Ａｒは、前記２－ピリジン環のオルト位に有するベンゼン環であって、さらに当該ベンゼン環のオルト位にピリジン環を有する。Ｒは、置換基を表す。ｎは、０又は１以上の整数を表す。］
一般式（２）：Ｈ－Ｘ
［一般式（２）中、Ｘは機能性基を表す。Ｈは、プロトンＮＭＲにおいて低磁場側へシフトする水素原子を表す。］ 1. A mixed composition for an organic electroluminescence device containing an active hydrogen compound, a nitrogen-containing aromatic heterocyclic compound and an organic solvent Y,
At least one of the signals of the active hydrogen compound assigned using proton NMR is at a lower magnetic field in the presence of the nitrogen-containing heterocyclic compound than in the system in which the nitrogen-containing heterocyclic compound is not present. is shifted to the side, and
The organic solvent Y is liquid at room temperature ,
The nitrogen-containing aromatic heterocyclic compound has a structure represented by the following general formula (1), and
A mixed composition for an organic electroluminescence device, wherein the active hydrogen compound has a structure represented by the following general formula (2) .

[In general formula (1), ring A1 formed with =N- represents a 2-pyridine ring. Ar is a benzene ring ortho-positioned to the 2-pyridine ring, and further has a pyridine ring ortho-positioned to the benzene ring. R represents a substituent. n represents an integer of 0 or 1 or more. ]
General formula (2): HX
[In general formula (2), X represents a functional group. H represents a hydrogen atom that shifts downfield in proton NMR. ]

2 . 2. The mixture for an organic electroluminescence device according to item 1, wherein the active hydrogen compound having the structure represented by the general formula (2) is an alcohol having the structure represented by the following general formula (2-1) Composition.
General formula (2-1): H—O—X′
[In general formula (2-1), X′ represents an optionally substituted hydrocarbon group. ]

3 . 3. The mixed composition for an organic electroluminescence device according to item 1 or 2 , wherein the active hydrogen compound having the structure represented by the general formula (2) is a fluorinated alcohol.

4 . 4. The mixed composition for an organic electroluminescence device according to any one of items 1 to 3 , wherein the content of the active hydrogen compound is 40% by mass or less with respect to the total amount of solvent in the mixed composition. thing.

5 . 5. The mixed composition for an organic electroluminescence device according to any one of items 1 to 4 , wherein the content of the active hydrogen compound is 10% by mass or less with respect to the total amount of solvent in the mixed composition. thing.

6 . 6. The mixed composition for an organic electroluminescence device according to any one of claims 1 to 5 , wherein the organic solvent Y is an organic compound having no hydrogen atoms exhibiting hydrogen bonding properties.

According to the above means of the present invention, it is possible to provide a mixed composition for an organic electroluminescence device, which can improve the solubility of a solute in a solvent and can be suitably used for an inkjet printing method.
Although the expression mechanism or action mechanism of the effects of the present invention has not been clarified, it is speculated as follows.
As in the present invention, at least one of the signals of the active hydrogen compound assigned using proton NMR is a nitrogen-containing aromatic heterocyclic compound compared to a system in which the nitrogen-containing heterocyclic compound is absent. In the presence of , the active hydrogen compound and the nitrogen-containing aromatic heterocyclic compound are hydrogen-bonded. Due to the formation of this hydrogen bond, the active hydrogen compound, which is the solvent, acts as a bulky substituent on the nitrogen-containing aromatic heterocyclic compound, which is the solute. As a result, aggregation is suppressed and the solubility of the solute in the solvent is improved.
And this effect is expressed even when the content of the active hydrogen compound is about 40% by mass or less with respect to the total solvent amount of the mixed composition, so the ink jet printing method, which could not be used conventionally from the viewpoint of solubility It becomes possible to apply a suitable solvent to the manufacturing process. Therefore, it is expected that this will lead to the development of organic EL devices with higher efficiency and higher precision, since the range of solvent selection will be expanded.

Schematic diagram of the lighting system Schematic diagram of lighting system

The mixed composition for an organic electroluminescent device of the present invention is a mixed composition for an organic electroluminescent device containing an active hydrogen compound, a nitrogen-containing aromatic heterocyclic compound, and an organic solvent Y, and is characterized by using proton NMR. At least one of the signals of the active hydrogen compound is shifted to the low magnetic field side in the presence of the nitrogen-containing aromatic heterocyclic compound compared to the system in which the nitrogen-containing heterocyclic compound is not present. and the organic solvent Y is liquid at room temperature.
This feature is a technical feature common to or corresponding to each of the following embodiments.

As an embodiment of the present invention, the nitrogen-containing aromatic heterocyclic compound has a structure represented by the general formula (1), and the active hydrogen compound has a structure represented by the general formula (2). It is preferable in that the hydrogen-bonding interaction between the nitrogen-containing aromatic heterocyclic compound and the active hydrogen compound works effectively, thereby improving the solubility of the nitrogen-containing aromatic heterocyclic compound as a solute. .
Further, from the viewpoint of improving solubility, A1 in the general formula (1) is a pyridine ring or a condensed ring in which a ring is further condensed to the pyridine ring, and Ar in the general formula (1) has a substituent. It is preferably a benzene ring which may be substituted.
Furthermore, the nitrogen-containing aromatic heterocyclic compound having the structure represented by the general formula (1) has the structure represented by the general formula (1-1), It is preferable that the active hydrogen compound having the structure represented by the general formula (2-1) is an alcohol having a structure represented by the general formula (2-1). In particular, it is preferable that the active hydrogen compound having the structure represented by the general formula (2) is a fluorinated alcohol.

When the active hydrogen compound is 40% by mass or less with respect to the total solvent amount of the mixed composition, the head is not damaged while maintaining the solubility in the nitrogen-containing aromatic heterocyclic compound, which is suitable for the inkjet printing method. It is preferable in that a mixed solvent can be obtained. In particular, the content of the active hydrogen compound is preferably 10% by mass or less with respect to the total amount of solvent in the mixed composition.
Furthermore, in order to maintain solubility in a solution, it is more preferably 1% by mass or more.

It is preferable that the organic solvent Y is an organic compound that does not have hydrogen atoms that exhibit hydrogen bonding properties, in that it does not inhibit the interaction between the nitrogen-containing aromatic heterocyclic compound and the active hydrogen compound.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, its constituent elements, and modes and modes for carrying out the present invention will be described below. In the present application, "-" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.

[Outline of Mixed Composition for Organic Electroluminescence Device of the Present Invention]
A mixed composition for an organic electroluminescence device of the present invention (hereinafter also simply referred to as a mixed composition) is an organic electroluminescent device containing an active hydrogen compound, a nitrogen-containing aromatic heterocyclic compound and an organic solvent Y which is liquid at room temperature. A mixed composition for a luminescence device, wherein at least one of the signals of the active hydrogen compound assigned using proton NMR is higher than that of a system in which the nitrogen-containing aromatic heterocyclic compound is not present. In the presence of heteroaromatic compounds, it shifts to the low magnetic field side.

<Active hydrogen compound>
In the present application, the term "active hydrogen compound" refers to a hydrogen atom capable of interacting with a nitrogen-containing aromatic heterocyclic compound in the presence of the nitrogen-containing heterocyclic compound, such as oxygen (O), which has a high electronegativity. A compound having an active hydrogen atom capable of forming a hydrogen bond, such as a hydrogen atom bonded to nitrogen (N) or the like.
Specifically, compounds having easily liberated hydrogen atoms in their molecules, such as alcohols, phenols, carboxylic acids, primary or secondary amine compounds, and active methylene compounds. In particular, the active hydrogen compound according to the present invention preferably has a structure represented by general (2) below. Moreover, in the present invention, it is preferably a compound that can function as a solvent.
General formula (2): HX
[In general formula (2), X represents a functional group. H represents a hydrogen atom that shifts downfield in proton NMR. ]

In the general formula (2), X represents a functional group. A functional group refers to a functional group that characterizes the properties of each compound, and refers to a site other than the easily liberated hydrogen atom in the compound. Examples thereof include an optionally substituted alkyl group, alkoxy group, carbonyl group and the like.

Moreover, it is preferable that the active hydrogen compound having the structure represented by the general formula (2) is an alcohol having the structure represented by the following general formula (2-1).
General formula (2-1): H—O—X′
[In general formula (2-1), X′ represents an optionally substituted hydrocarbon group. ]

In the general formula (2-1), X′ represents an optionally substituted hydrocarbon group, such as alcohol (methanol, ethanol, isopropanol, 1-propanol, butanol, etc.), carboxylic acid (formic acid, acetic acid , propionic acid, etc.).

Alcohols substituted with fluorine atoms (fluorinated alcohols) are more preferred, such as 2,2,3,3-tetrafluoro-1-propanol (TFPO), 2,2,3,3,3 - pentafluoro-1-propanol (PFPO), 2-trifluoromethyl-2-propanol (TFMPO), 2,2,3,4,4,4-hexafluoro-1-butanol (HFBO), 2,2, 3,3,4,4,5,5-octafluoro-1-pentanol (OFPO), 2,3-difluorobenzyl alcohol (DFBA), 2,2,2-trifluoroethanol (TFEO), 1,3 -difluoropropan-2-ol (DFPO), 1H,1H-pentadecafluoro-1-octanol (PDFOO), 1H,1H,2H,2H-tridecafluoro-1-n-octanol (TDFOO), 1H,1H ,7H-dodecafluoro-1-heptanol (DFHO), 1H,1H,9H-hexadecafluoro-1-nonanol (DFHO), 1H,1H,2H,2H-heptadecafluoro-1-decanol (HDFDO), 2 -perfluorohexylethanol (PFHEO) and the like.

Furthermore, at least one of the signals of the active hydrogen compound assigned using proton NMR is higher in the presence of the nitrogen-containing heterocyclic compound than in the system in which the nitrogen-containing heterocyclic compound is not present. It is shifted to the low magnetic field side. That is, when the nitrogen-containing aromatic heterocyclic compound is added to the active hydrogen compound and measured by proton NMR, the chemical shift of the proton NMR representing at least one H of the active hydrogen compound is the presence of the nitrogen-containing aromatic heterocyclic compound. In the presence of a nitrogen-containing aromatic heterocyclic compound, it shifts to the low magnetic field side compared to the system without the system. In the presence of an equal amount of the nitrogen-containing aromatic heterocyclic compound, it is more preferable to shift to the low magnetic field side by 0.2 ppm or more.
When such an active hydrogen compound is used, as shown in the following general formula (3), interactions such as hydrogen bonding work effectively between the active hydrogen compound and the nitrogen-containing aromatic heterocyclic compound. to form a pseudo-complex. For this reason, it is thought that the nitrogen-containing aromatic heterocyclic compounds can be prevented from aggregating with each other, and a more stably dispersed coating liquid can be produced.
In addition, since a change in NMR chemical shift is also observed and an improvement in solubility is also confirmed, it is preferable that the active hydrogen compound contains 20 times or more the number of moles of the nitrogen-containing aromatic heterocyclic compound.

前記一般式（３）中、Ａ１、Ａｒ、Ｒ、ｎ、Ｘは、後述する一般式（１）におけるＡ１、Ａｒ、Ｒ、ｎ、及び、前記一般式（２）におけるＸと同義である。

In general formula (3), A1, Ar, R, n, and X have the same meanings as A1, Ar, R, and n in general formula (1) described later and X in general formula (2).

The active hydrogen compound is used as a solvent together with the organic solvent Y in the present invention.

［一般式（１）中、＝Ｎ－を含んで形成される環Ａ１は、芳香族複素環を表す。Ａｒは、置換基を有していてもよい芳香族炭化水素環又は芳香族複素環を表す。Ｒは、置換基を表す。ｎは、０又は１以上の整数を表す。］<Nitrogen-containing aromatic heterocyclic compound>
The nitrogen-containing aromatic heterocyclic compound in the invention has a structure represented by the following general formula (1).

[In general formula (1), ring A1 formed with =N- represents an aromatic heterocycle. Ar represents an optionally substituted aromatic hydrocarbon ring or aromatic heterocyclic ring. R represents a substituent. n represents an integer of 0 or 1 or more. ]

In the general formula (1), the ring A1 formed containing =N- represents an aromatic heterocyclic ring, and the aromatic heterocyclic ring includes an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring. , a tetrazole ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a pyridine ring, or condensed rings formed by further condensing these rings, etc. Among them, a pyridine ring or a condensed ring formed by further condensing a ring to a pyridine ring is preferable.
R represents a substituent, and examples of the substituent include a hydrogen atom, a halogen atom, an arylalkyl group, a cycloalkyl group, an aryl group, and a cyano group.
Ar represents an optionally substituted aromatic hydrocarbon ring or an aromatic heterocyclic ring, specifically a benzene ring optionally having a substituent, a condensed ring and the like, among which A benzene ring which may have a substituent is preferred.
The general formula (1) is more preferably a structure of the following general formula (1-1), and most preferably, A1 is a 2-pyridine ring and Ar is substituted at the ortho position of the 2-pyridine ring. It is a compound having an orthophenylpyridine structure, which is a benzene ring having a group.

［一般式（１－１）中、Ａｒは、置換基を有していてもよい芳香族炭化水素環又は芳香族複素環を表す。Ｒは、置換基を表す。ｎは、０又は１以上の整数を表す。］

[In general formula (1-1), Ar represents an optionally substituted aromatic hydrocarbon ring or aromatic heterocyclic ring. R represents a substituent. n represents an integer of 0 or 1 or more. ]

In the general formula (1-1), Ar represents an optionally substituted aromatic hydrocarbon ring or aromatic heterocyclic ring, specifically the same as Ar in the general formula (1). be.
R represents a substituent, and is specifically the same as R in the general formula (1).

The nitrogen-containing aromatic heterocyclic compound having the ortho-phenylpyridine structure is generally known to have strong crystallinity and low solubility in general organic solvents.
By using a fluorinated alcohol-based solvent such as TFPO, the mechanism described above in the section on the active hydrogen compound is thought to work and the compound dissolves.
Examples of compounds having an orthophenylpyridine structure that can be used in the present invention include compounds described in Japanese Patent No. 3925265 and the like.

Exemplary compounds preferable as the nitrogen-containing aromatic heterocyclic compound in the present invention and reference compounds thereof are shown below.

<Organic solvent Y>
The organic solvent Y in the present invention is an organic compound that is liquid at room temperature (25° C.) and has no hydrogen atoms that exhibit hydrogen bonding properties.
Further, the organic solvent Y is used as a solvent together with the active hydrogen compound in the present invention.
Preferred examples of the organic solvent Y include aprotic solvents such as chloroform, toluene, deuterated chloroform, dichloromethane, diethyl ether, tetrahydrofuran, ethyl acetate, acetone, and acetonitrile.

[Structure of organic EL element]
Typical device configurations in the organic EL device manufactured using the mixed composition for the organic EL device of the present invention include the following configurations, but are not limited thereto.
(i) anode/emissive layer/cathode (ii) anode/emissive layer/electron transport layer/cathode (iii) anode/hole transport layer/emissive layer/cathode (iv) anode/hole transport layer/emissive layer/electron transport layer/cathode (v) anode/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode (vi) anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/cathode ( vii) Anode/Hole Injection Layer/Hole Transport Layer/(Electron Blocking Layer/) Emitting Layer/(Hole Blocking Layer/) Electron Transport Layer/Electron Injection Layer/Cathode Of the above configurations, (vii) is preferred. used, but not limited to.

The light-emitting layer according to the present invention is composed of a single layer or multiple layers, and when there are multiple light-emitting layers, a non-light-emitting intermediate layer may be provided between each light-emitting layer. If necessary, a hole-blocking layer (also referred to as a hole-blocking layer) or an electron-injecting layer (also referred to as a cathode buffer layer) may be provided between the light-emitting layer and the cathode. An electron blocking layer (also referred to as an electron blocking 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. Moreover, you may comprise by multiple layers.
The hole transport 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 transport layer. Moreover, you may comprise by multiple layers.
In the above representative device structure, the layers other than the anode and cathode are also referred to as "organic layers".

(tandem structure)
Further, the organic EL element according to the present invention may be a so-called tandem structure element in which a plurality of light emitting units each including at least one light emitting layer are laminated.
As a representative element configuration of the tandem structure, for example, the following configuration can be given.
anode/first light-emitting unit/second light-emitting unit/third light-emitting unit/cathode anode/first light-emitting unit/intermediate layer/second light-emitting unit/intermediate layer/third light-emitting unit/cathode where the first light-emitting unit , the second light-emitting unit and the third light-emitting unit may all be the same or different. Also, two light emitting units may be the same and the remaining one may be different.
Further, the third light emitting unit may be omitted, and on the other hand, an additional light emitting unit or an intermediate layer may be provided between the third light emitting unit and the electrode.

A plurality of light-emitting units may be directly laminated or may be laminated via an intermediate layer. Also known as an insulating layer, known materials and structures can be used as long as the layer 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 materials used for the intermediate layer include ITO (indium tin oxide), IZO (indium 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 two-layer films, SnO ₂ /Ag/SnO ₂ , ZnO/Ag/ Multilayer films such as ZnO, _Bi2O3 /Au/ _{Bi2O3 , TiO2} /TiN/ _{TiO2 , TiO2} /ZrN/ _TiO2 , and conductive organic layers such as fullerenes such as _C60 and oligothiophene. , metal phthalocyanines, metal-free phthalocyanines, metal porphyrins, metal-free porphyrins and other conductive organic compound layers, but the present invention is not limited thereto.

Preferred structures in the light-emitting unit include, for example, structures (i) to (vii) exemplified in the representative element structures described above, with the anode and cathode removed, but the present invention is limited to these. not.

Specific examples of tandem-type organic EL devices include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. Publication No. 2005/009087, JP 2006-228712, JP 2006-24791, JP 2006-49393, JP 2006-49394, JP 2006-49396, JP 2011-96679, Patent JP 2005-340187, JP 4711424, JP 3496681, JP 3884564, JP 4213169, JP 2010-192719, JP 2009-076929, JP 2008-078414, JP 2007 -059848, JP-A-2003-272860, JP-A-2003-045676, International Publication No. 2005/094130, etc., but the present invention is not limited thereto.

Each layer constituting the organic EL device according to the present invention will be described below.
《Light emitting layer》
The light-emitting layer according to the present invention is a layer in which electrons and holes injected from an electrode or an adjacent layer recombine and provide a field for light emission via excitons, and the light-emitting portion is a layer of the light-emitting layer. It may be inside or at the interface between the light-emitting layer and the adjacent layer. The light-emitting layer according to the present invention is not particularly limited in its structure as long as it satisfies the requirements defined in the present invention.
The total thickness of the light-emitting layer is not particularly limited, but it is necessary to ensure uniformity of the layer to be formed, prevent application of an unnecessary high voltage during light emission, and improve the stability of the emission color with respect to the driving current. From the viewpoint, it is preferably adjusted within the range of 2 nm to 5 μm, more preferably within the range of 2 nm to 500 nm, further preferably within the range of 5 nm to 200 nm.
Further, the thickness of each light emitting layer is preferably adjusted within the range of 2 nm to 1 μm, more preferably within the range of 2 nm to 200 nm, and still more preferably within the range of 3 nm to 150 nm. .

The light-emitting layer preferably contains a light-emitting dopant (also referred to as a light-emitting dopant compound, dopant compound, or simply dopant) and a host compound (also referred to as matrix material, or light-emitting host compound, or simply host).

(1) Luminescent dopant As the luminescent dopant, a fluorescent dopant (also referred to as a fluorescent dopant or a fluorescent compound) and a phosphorescent dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) are preferably used. In the present invention, at least one light-emitting layer preferably contains a phosphorescent light-emitting dopant.
The concentration of the emissive dopant in the emissive layer can be arbitrarily determined based on the particular dopant used and device requirements, and should be contained in a uniform concentration along the thickness of the emissive layer. and may have an arbitrary concentration distribution.
Moreover, the light-emitting dopant according to the present invention may be used in combination of a plurality of types, or may be used in combination of dopants having different structures, or in combination of a fluorescent light-emitting dopant and a phosphorescent light-emitting dopant. This makes it possible to obtain an arbitrary emission color.

The color emitted by the organic EL element according to the present invention is determined by a spectral radiance meter CS-1000 ( Konica Minolta Co., Ltd.) is applied to the CIE chromaticity coordinates to determine the color.
In the present invention, it is also preferable that one or more light-emitting layers contain a plurality of light-emitting dopants with different emission colors to exhibit white light emission.
Although there is no particular limitation on the combination of dopants that emit white light, examples thereof include a combination of blue and orange, and a combination of blue, green, and red.
The white color in the organic EL device according to the present invention is not particularly limited, and may be an orange-like white color or a blue-like white color. In addition, the chromaticity in the CIE1931 color system at 1000 cd/m ² is preferably within the range of x=0.39±0.09 and y=0.38±0.08.

(1.1) Phosphorescent dopant The phosphorescent dopant (hereinafter also referred to as “phosphorescent dopant”) according to the present invention will be described.
The phosphorescent dopant according to the present invention is a compound in which emission from excited triplets is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. The phosphorescence quantum yield is preferably 0.1 or higher, although it is defined as a compound with a phosphorescence quantum yield of 0.01 or higher at °C.

The phosphorescence quantum yield can be measured by the method described in Experimental Chemistry Course 7, 4th edition, Spectroscopy II, page 398 (1992 edition, Maruzen). Phosphorescence quantum yield in solution can be measured using various solvents, the phosphorescence dopant according to the present invention, the phosphorescence quantum yield (0.01 or more) is achieved in any of the solvents Just do it.
There are two types of light emission principle of a phosphorescent dopant. One is recombination of carriers on the host compound to which carriers are 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 in which light emission from the phosphorescent dopant is obtained by allowing the phosphorescent dopant to emit light. The other is a carrier trap type in which the phosphorescent dopant acts as a carrier trap, recombination of carriers occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. In either case, the condition is that the excited state energy of the phosphorescent dopant is 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 and used from known ones used in the light-emitting layer of the organic EL device.
Specific examples of known phosphorescent dopants that can be used in the present invention include the compounds described in the following documents.
Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), WO2009/100991, WO2008/101842, WO2003/040257, US2006/835469, US2006/0202194, United States Patent Publication No. 2007/0087321, US Patent Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. Int. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), WO 2009/050290, WO 2002/015645, WO 2009/000673, U.S. Patent Publication 2002/0034656, U.S. Patent No. 7332232, U.S. Patent Publication No. US Patent Publication No. 2009/0039776; US Patent Publication No. 6921915; 0165846, US2008/0015355, US7250226, US7396598, US2006/0263635, US2003/0138657, US2003/0152802 , U.S. Pat. No. 7,090,928, Angew. Chem. Int. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), WO 2002/002714, WO 2006/009024, WO 2006/056418, WO 2005/019373, WO 2005/123873, WO 2007/004380, WO 2006/082742, US Patent Publication 2006/0251923, US Patent Publication 2005/0260441, US Patent No. 7393599, US Patent No. 7534505, US Patent No. 7445855, United States Patent Publication No. 2007/0190359, U.S. Patent Publication No. 2008/0297033, U.S. Patent Publication No. 7338722, U.S. Patent Publication No. 2002/0134984, U.S. Patent No. 7279704, U.S. Patent Publication No. 2006/098120, U.S. Patent Publication WO 2006/103874, WO 2005/076380, WO 2010/032663, WO 2008/140115, WO 2007/052431, WO 2011/134013, WO 2011 /157339, WO2010/086089, WO2009/113646, WO2012/020327, WO2011/051404, WO2011/004639, WO2011/073149 No., US Patent Publication No. 2012/228583, US Patent Publication No. 2012/212126, JP 2012-069737, JP 2012-195554, JP 2009-114086, JP 2003-81988, JP 2002-302671, JP-A-2002-363552, and the like.

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

(1.2) Fluorescent dopant The fluorescent dopant (hereinafter also referred to as “fluorescent dopant”) according to the present invention will be described.
The fluorescent dopant according to the present invention is a compound capable of emitting light from an excited singlet, and is not particularly limited as long as light emission from an excited singlet can be observed.
Examples of fluorescent dopants according to 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 coumarin derivatives. , pyran derivatives, cyanine derivatives, croconium derivatives, squarium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, or rare earth complex compounds.

In recent years, light-emitting dopants using delayed fluorescence have also been developed, and these may be used.
Specific examples of the luminescent dopant utilizing delayed fluorescence, for example, WO 2011/156793, JP 2011-213643, JP 2010-93181, etc. compounds described in, but the present invention these is not limited to

(2) Host compound The host compound according to the present invention is a compound that is mainly responsible for charge injection and transport in the light-emitting layer, and its own light emission is substantially not observed in the organic EL device.
A compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25° C.) of less than 0.1 is preferred, and a phosphorescence quantum yield of less than 0.01 is more preferred. Further, among the compounds contained in the light-emitting layer, the mass ratio in the layer is preferably 20% or more.
Also, 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 multiple types. By using a plurality of types of host compounds, it is possible to adjust the movement of electric charges, and to improve the efficiency of the organic EL device.
The host compound that can be used in the present invention is not particularly limited, and compounds that are conventionally used in organic EL devices can be used. It may be a low-molecular compound, a polymer compound having repeating units, or a compound having a reactive group such as a vinyl group or an epoxy group.

Known host compounds have hole-transporting ability or electron-transporting ability, prevent emission from becoming longer in wavelength, and stabilize the organic EL element against heat generation during high-temperature operation and during element operation. It is preferable to have a high glass transition temperature (Tg) from the viewpoint of operating with a high temperature. Tg is preferably 90° C. or higher, more preferably 120° C. or higher.
Here, the glass transition point (Tg) is a value determined by a method based on JIS-K-7121 using DSC (Differential Scanning Calorimetry).

Specific examples of known host compounds used in the organic EL device of the invention include compounds described in the following documents, but the invention is not limited thereto.
JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 -3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002- 302516, 2002-305083, 2002-305084, 2002-308837, US Patent Publication No. 2003/0175553, US Patent Publication No. 2006/0280965, US Patent Publication No. 2005/0112407 , U.S. Patent Publication No. 2009/0017330, U.S. Patent Publication No. 2009/0030202, U.S. Patent Publication No. 2005/0238919, WO 2001/039234, WO 2009/021126, WO 2008/ WO 2004/093207, WO 2005/089025, WO 2007/063796, WO 2007/063754, WO 2004/107822, WO 2005/030900 , International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/023947, JP 2008-074939, JP 2007-254297, EP2034538, etc. is.

《Electron transport layer》
In the present invention, the electron-transporting layer is made of a material having a function of transporting electrons, as long as it has a function of transmitting electrons injected from the cathode to the light-emitting layer.
The total thickness of the electron transport layer in the present invention is not particularly limited, but is usually within the range of 2 nm to 5 μm, more preferably within the range of 2 nm to 500 nm, and still more preferably within the range of 5 to 200 nm. is.

The material used for the electron transport layer (hereinafter referred to as an electron transport material) may have either electron injection or transport properties or hole blocking properties. Any one can be selected and used.
For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more carbon atoms constituting the carbazole ring are substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, azatriphenylene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, etc.), dibenzofuran derivatives, Examples include dibenzothiophene derivatives, silole derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

In addition, metal complexes having a quinolinol skeleton or a dibenzoquinolinol skeleton in the ligand, such as tris(8-quinolinol)aluminum (Alq ₃ ), 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 of 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 phthalocyanines, or those whose terminals are substituted with alkyl groups, sulfonic acid groups, or the like can also be preferably used as electron transport materials. In addition, the distyrylpyrazine derivative exemplified as the material for the light-emitting layer can also be used as an electron transport material. can also be used as an electron transport material.
Also, polymer materials in which these materials are introduced into the polymer chain or those materials are used as the main chain of the polymer can also be used.

In the electron transport layer according to 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 dopants include n-type dopants such as metal compounds such as metal complexes and metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Am. Appl. Phys. , 95, 5773 (2004).

Specific examples of known electron-transporting materials suitable for use in the organic EL device according to the present invention include the compounds described in the following documents, but the present invention is not limited thereto.
US Patent No. 6528187, US Patent No. 7230107, US Patent Publication No. 2005/0025993, US Patent Publication No. 2004/0036077, US Patent Publication No. 2009/0115316, US Patent Publication No. 2009/0101870, US Patent Publication No. 2009/0179554, WO 2003/060956, WO 2008/132085, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79, 156 (2001), US Pat. /067931, WO2007/086552, WO2008/114690, WO2009/069442, WO2009/066779, WO2009/054253, WO2011/086935 No., International Publication No. 2010/150593, International Publication No. 2010/047707, EP2311826, JP 2010-251675, JP 2009-209133, JP 2009-124114, JP 2008-277810, Patent JP 2006-156445, JP 2005-340122, JP 2003-45662, JP 2003-31367, JP 2003-282270, WO 2012/115034, and the like.

More preferred electron transport 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-transporting material may be used singly or in combination of two or more.

《Hole blocking layer》
In a broad sense, the hole-blocking layer is a layer having the function of an electron-transporting layer. can improve the recombination probability of electrons and holes.
Moreover, the configuration 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 is preferably provided adjacent to the cathode side of the light-emitting layer.
The film thickness of the hole blocking layer is preferably in the range of 3 to 100 nm, 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-transporting layer described above is preferably used, and the material used for 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") according to the present invention is a layer provided between the cathode and the light-emitting layer to reduce the driving voltage and improve the luminance of light emission. Forefront of industrialization (published by NTS on Nov. 30, 1998), Volume 2, Chapter 2 "Electrode materials" (pp. 123-166).
In the present invention, the electron injection layer is optionally provided, and may exist 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 its thickness is preferably in the range of 0.1 to 5 nm depending on the material. Alternatively, it may be a non-uniform film in which the constituent material exists intermittently.

Details of the electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, etc. Specific examples of materials preferably used for the electron injection 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 Metal oxides typified by aluminum and metal complexes typified by lithium 8-hydroxyquinolate (Liq) and the like are included. It is also possible to use the aforementioned electron transport materials.
Moreover, the material used for the electron injection layer may be used alone, or a plurality of materials may be used in combination.

<<Hole transport layer>>
In the present invention, the hole-transporting layer is 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 is not particularly limited, but is usually in the range of 5 nm to 5 μm, more preferably in the range of 2 to 500 nm, still more preferably in the range of 5 to 200 nm. be.

The material used for the hole transport layer (hereinafter referred to as a hole transport material) may have either a hole injection or transport property or an electron barrier property. Any one can be selected and used from.
For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives. , indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, polyvinylcarbazole, polymeric materials or oligomers with aromatic amines introduced into the main chain or side chain, polysilane, conductive organic polymers or oligomers (eg, PEDOT:PSS, aniline copolymers, polyaniline, polythiophene, etc.), and the like.

Examples of triarylamine derivatives include benzidine-type derivatives such as α-NPD, starburst-type derivatives such as MTDATA, and compounds having fluorene or anthracene in the triarylamine-linked core portion.
Hexaazatriphenylene derivatives as described in JP-A-2003-519432, JP-A-2006-135145, etc. can also be used as a hole transport material.
Furthermore, an impurity-doped hole-transporting layer having a high p-property can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175; Appl. Phys. , 95, 5773 (2004).
Also, Japanese Patent Application Laid-Open No. 11-251067, J. Am. Huang et. al. So-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC, as described in Applied Physics Letters 80 (2002), p.139, can also be used. Further, an ortho-metalated organometallic complex having Ir or Pt as a central metal such as Ir(ppy) ₃ is preferably used.
As the hole-transporting material, those mentioned above can be used. Polymeric materials, oligomers, or the like are preferably used.

Specific examples of known preferred hole-transporting materials used in the organic EL device according to the present invention include the compounds described in the following documents in addition to the above-mentioned documents. Not limited.
For example, Appl. Phys. Lett. 69, 2160 (1996); Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. 111, 421 (2000); SID Symposium Digest, 37, 923 (2006); Mater. Chem. 3, 319 (1993), Adv. Mater. 6, 677 (1994), Chem. Mater. 15, 3148 (2003), US Patent Publication No. 2003/0162053, US Patent Publication No. 2002/0158242, US Patent Publication No. 2006/0240279, US Patent Publication No. 2008/0220265, US Patent No. 5061569, International Pub. 0018221,
WO 2012/115034, JP 2003-519432, JP 2006-135145, US Patent Application No. 13/585981, and the like.
The hole-transporting material may be used singly or in combination of two or more.

《Electron blocking layer》
In a broad sense, the electron blocking layer is a layer that has the function of a hole transport layer, preferably made of a material that has a function of transporting holes but has a small ability to transport electrons. can improve the recombination probability of electrons and holes.
Moreover, the configuration of the hole transport layer described above can be used as the electron blocking layer according to the present invention, if necessary.
The electron blocking layer is preferably provided adjacent to the anode side of the light emitting layer.
Also, the thickness of the electron blocking layer is preferably in the range of 3 to 100 nm, 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 transport layer is preferably used, and the material used for the host compound is also preferably used for the electron blocking layer.

《Hole Injection Layer》
The hole injection layer (also referred to as "anode buffer layer") according to 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 luminance of light emission. The Forefront of Industrialization (published by NTS on Nov. 30, 1998)", Volume 2, Chapter 2 "Electrode Materials" (pp. 123-166).
In the present invention, the hole injection layer is optionally provided, 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 described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Materials used for the hole injection layer include, for example, Materials used for the above-mentioned hole transport layer and the like can be mentioned.
Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-A-2003-519432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon, polyaniline (emeral Din), conductive polymers such as polythiophene, ortho-metalated complexes such as tris(2-phenylpyridine)iridium complexes, and triarylamine derivatives are preferred.
The materials used for the hole injection layer described above may be used alone, or a plurality of materials may be used in combination.

《Inclusions》
The organic layer in the present invention described above may further contain other inclusions.
Inclusions include, for example, halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals such as Pd, Ca and Na, alkaline earth metals, transition metal compounds, complexes, and salts.
The content of the ingredients can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, and still more preferably 50 ppm or less with respect to the total mass% of the layer to be contained. .
However, depending on the purpose of improving the transportability of electrons and holes, the purpose of making the energy transfer of excitons advantageous, etc., it is not within this range.

"anode"
As the anode in the organic EL element, an electrode material having a large work function (4 eV or more, preferably 4.5 V or more), metal, alloy, electrically conductive compound or mixture thereof is preferably used. Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. A material such as IDIXO (In ₂ O ₃ —ZnO) that is amorphous and capable of forming a transparent conductive film may also be used.

The anode may be formed by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering, and then forming a pattern of a desired shape by photolithography, or when pattern accuracy is not so required (approximately 100 μm or more). A 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 may be used. When light is extracted from this anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance of the anode is several hundred Ω/sq. The following are preferred.
Although the film thickness of the anode depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

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

The cathode can be produced by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. Moreover, the sheet resistance as a cathode is several hundred Ω/sq. The following is preferable, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.
In order to allow the emitted light to pass therethrough, if either the anode or the cathode of the organic EL element is transparent or translucent, the luminance of the emitted light is improved, which is convenient.
In addition, a transparent or translucent cathode can be produced by forming the above-mentioned metal in a thickness of 1 to 20 nm on the cathode and then forming thereon a conductive transparent material mentioned in the explanation of the anode. can be applied to fabricate devices in which both the anode and cathode are transparent.

《Support substrate》
The support substrate (hereinafter also referred to as base, substrate, base material, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited to glass, plastic, or the like, and may be transparent. It can be transparent or opaque. When light is extracted from the support substrate side, the support substrate is preferably transparent. Glass, quartz, and a transparent resin film can be mentioned as a transparent support substrate that is preferably used. A particularly preferable support substrate is a resin film capable of imparting flexibility to the organic EL element.

Examples of resin films include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate, or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylates, Arton (trade name manufactured by JSR) or APEL (trade name, manufactured by Mitsui Chemicals, Inc.).

A coating of an inorganic substance, an organic substance, or a hybrid coating of both may be formed on the surface of the resin film, and the water vapor transmission rate (25 ± 0.5 ° C. , relative humidity (90±2)% RH) is preferably a barrier film of 0.01 g/(m ² 24 h) or less, and oxygen measured by a method in accordance with JIS K 7126-1987 A high barrier film having a permeability of 10 ⁻³ mL/(m ² ·24 h·atm) or less and a water vapor permeability of 10 ⁻⁵ g/(m ² ·24 h) or less is preferable.

As the material for forming the barrier film, any material can be used as long as it has a function of suppressing the infiltration of substances such as moisture and oxygen that cause deterioration of the device. For example, silicon oxide, silicon dioxide, silicon nitride, and the like can be used. Furthermore, in order to improve the fragility of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The order of lamination of the inorganic layer and the organic layer is not particularly limited, but it is preferable to alternately laminate the two layers a plurality of times.

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

Examples of opaque support substrates include metal plates such as aluminum and stainless steel, films, opaque resin substrates, ceramic substrates, and the like.
The external extraction quantum efficiency of light emitted from the organic EL device according to the present invention at room temperature is preferably 1% or more, more preferably 5% or more.
Here, external extraction quantum efficiency (%)=number of photons emitted outside the organic EL element/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 for converting the emission color from the organic EL element into multiple colors using a phosphor may be used in combination.

<Method for preparing organic EL element>
A method for forming the organic layers (hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) in the present invention will be described.
The method for forming the organic layer is not particularly limited, and conventionally known forming methods such as a vacuum deposition method and a wet method (also referred to as a wet process) can be used. When using, a wet method is used.
Examples of wet methods include printing methods such as gravure printing, flexographic printing, screen printing, spin coating, casting, inkjet printing, die coating, blade coating, bar coating, roll coating, There are dip coating method, spray coating method, curtain coating method, doctor coating method, LB method (Langmuir-Blodgett method) and the like. Therefore, it is more preferable to apply by an inkjet printing method using an inkjet head.

Furthermore, different film forming methods may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, etc., but generally the boat heating temperature is 50 to 450° C., the degree of vacuum is 10 ⁻⁶ to 10 ⁻² Pa, and the vapor deposition rate is 0.01 to 0.01. 50 nm/sec, substrate temperature of −50 to 300° C., film thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.
In the present invention, it is preferable to form the organic layer from the hole-injection layer to the cathode in one evacuation, but it is also possible to remove the layer and apply a different film-forming method. In that case, it is preferable to carry out the work in a dry inert gas atmosphere.

《Inkjet head》
Inkjet heads applicable to the present invention include, for example, JP-A-2012-140017, JP-A-2013-010227, JP-A-2014-058171, JP-A-2014-097644, and JP-A-2015-142979. Publications, JP-A-2015-142980, JP-A-2016-002675, JP-A-2016-002682, JP-A-2016-107401, JP-A-2017-109476, JP-A-2017-177626, etc. can be appropriately selected and applied.

The coating liquid used in the wet method may be a solution in which the material forming the organic layer is uniformly dissolved in a liquid medium, or a dispersion liquid in which the material is dispersed as a solid content in the liquid medium. As a dispersion method, ultrasonic waves, high-shear force dispersion, media dispersion, or the like can be used for dispersion.
The liquid medium is not particularly limited in addition to the mixed composition for the organic EL device of the present invention. Ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, n-propyl methyl ketone, and cyclohexanone; aromatic solvents such as benzene, toluene, xylene, mesitylene, and cyclohexylbenzene; and aliphatic solvents such as cyclohexane, decalin, and dodecane. ester solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone and diethyl carbonate, ether solvents such as tetrahydrofuran and dioxane, dimethylformamide, dimethylacetamide and the like; alcohol solvents such as methanol, ethanol, 1-butanol and ethylene glycol; nitrile solvents such as acetonitrile and propionitrile; dimethyl sulfoxide;
From the viewpoint of drying the liquid medium quickly, the boiling point of these liquid media is preferably lower than the temperature of the drying treatment, specifically preferably in the range of 60 to 200°C, more preferably 80 to 180°C. is within the range of

The coating liquid may contain a surfactant for the purpose of controlling the coating range and for the purpose of suppressing the liquid flow associated with the surface tension gradient after coating (for example, the liquid flow that causes a phenomenon called coffee ring). can be done.
Examples of surfactants include anionic or nonionic surfactants from the viewpoint of the influence of moisture contained in the solvent, leveling properties, wettability to the substrate f1, and the like. Specifically, surfactants listed in International Publication No. 08/146681, Japanese Patent Application Laid-Open No. 2-41308, etc., such as fluorine-containing active agents, can be used.

As with the film thickness, the viscosity of the coating film can be appropriately selected depending on the functions required as the organic layer and the solubility or dispersibility of the organic material. can be selected within the range of s.
The film thickness of the coating film can be appropriately selected according to the functions required as the organic layer and the solubility or dispersibility of the organic material, and specifically, it can be selected within the range of 1 to 90 μm, for example.
After the coating film is formed by the wet method, a coating step of removing the above liquid medium can be included. Although the temperature of the drying process is not particularly limited, it is preferable to carry out the drying process at a temperature that does not damage the organic layer, the transparent electrode, or the substrate. Specifically, although it cannot be generalized because it varies depending on the composition of the coating liquid, for example, the temperature can be set to 80° C. or higher, and the upper limit is considered to be a possible range up to about 300° C. It is preferable that the time is about 10 seconds or more and 10 minutes or less. By setting it as such conditions, drying can be performed rapidly.

《Seal》
As a sealing means used for sealing the organic EL element, for example, a method of adhering a sealing member, an electrode, and a supporting substrate with an adhesive can be mentioned. The sealing member may be arranged so as to cover the display area of the organic EL element, and may be in the form of a concave plate or a flat plate. Moreover, transparency and electric insulation are not particularly limited.
Specifically, glass plates, polymer plates/films, metal plates/films, and the like can be mentioned. Examples of glass plates include soda-lime glass, barium-strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Further, examples of the polymer plate include polycarbonate, acryl, polyethylene terephthalate, polyether sulfide, polysulfone, and the like. Metal plates 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 since the organic EL device can be made thinner. Furthermore, the polymer film is JIS K
7126-1987, the oxygen permeability is 1×10 ⁻³ mL/m ² /24h or less, and the water vapor permeability (25±0. 5° C. and relative humidity (90±2)%) is preferably 1×10 ⁻³ g/(m ² /24 h) or less.

Sandblasting, chemical etching, or the like is used to process the sealing member into a concave shape.
Specific examples of adhesives include photocurable and heat-curable adhesives having reactive vinyl groups of acrylic acid-based oligomers and methacrylic acid-based oligomers, and moisture-curable adhesives such as 2-cyanoacrylic acid esters. be able to. Thermal and chemical curing types (two-liquid mixture) such as epoxy systems can also be mentioned. Hot-melt polyamides, polyesters and polyolefins can also be mentioned. Further, a cationic curing type ultraviolet curing type epoxy resin adhesive can be mentioned.
Since the organic EL element may be deteriorated by heat treatment, it is preferable to use a material that can be adhesively cured from room temperature to 80°C. Also, a desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing such as screen printing may be used.

It is also possible to form a sealing film by covering the outer side of the electrode on the side facing the support substrate with the organic layer sandwiched therebetween and the organic layer, forming an inorganic layer and an organic layer in contact with the support substrate. . In this case, the material for forming the film may be any material that has a function of suppressing the infiltration of substances that cause deterioration of the device, such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, and the like can be used. can.

Furthermore, in order to improve the fragility of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. A method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

An inert gas such as nitrogen or argon or an inert liquid such as fluorocarbon or silicone oil can be injected into the gap between the sealing member and the display area of the organic EL element in the gas phase and the liquid phase. preferable. A vacuum is also possible. Also, a hygroscopic compound can be sealed inside.
Hygroscopic compounds include metal oxides (e.g., sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (e.g., sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). , metal halides (e.g., calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (e.g., barium perchlorate, magnesium perchlorate, etc.), and anhydrous salts are preferably used for sulfates, metal halides and perchlorates.

<Protective film, protective plate>
A protective film or a protective plate may be provided on the outside of the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, so it is preferable to provide such a protective film and protective plate. As a material that can be used for this, the same glass plate, polymer plate/film, metal plate/film, etc. used for sealing can be used. is preferably used.

《Technology for improving light extraction》
The organic EL element in the present invention emits light inside a layer having a higher refractive index than air (within a refractive index range of about 1.6 to 2.1), and 15% to 20% of the light generated in the light emitting layer It is generally said that only a small amount of light can be extracted. This is because light incident on the interface (interface between the transparent substrate and the air) at an angle θ equal to or greater than the critical angle is totally reflected and cannot be extracted to the outside of the device. This is because the light is totally reflected between them, the light is guided through the transparent electrode or the light-emitting layer, and as a result, the light escapes in the lateral direction of the device.

Methods for improving the efficiency of extracting light include, for example, forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (see, for example, US Pat. No. 4,774,435); A method of improving efficiency by providing light-collecting properties (for example, JP-A-63-314795), a method of forming a reflective surface on the side surface of an element (for example, JP-A-1-220394), a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), a lower refractive index than the substrate between the substrate and the light emitter A method of introducing a flat layer having a coefficient (for example, Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any of the substrate, the transparent electrode layer and the 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 device. A method of forming a diffraction grating between layers (including between the substrate and the outside world) between the substrate and the light-emitting layer can be preferably used.
When a medium with a low refractive index is formed with a thickness longer than the wavelength of light between the transparent electrode and the transparent substrate, the light emitted from the transparent electrode is more efficiently extracted to the outside as the refractive index of the medium is lower. Become.
By combining these means, the present invention can obtain an element with even higher luminance or excellent durability.

Examples of the low refractive index layer include airgel, porous silica, magnesium fluoride, and fluoropolymers. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.
Moreover, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because when the thickness of the low-refractive-index medium becomes about the wavelength of light and reaches a thickness at which the electromagnetic wave seeped out by evanescence penetrates into the substrate, the effect of the low-refractive-index layer is weakened.

The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving the light extraction efficiency. This method utilizes the property that a diffraction grating can change the direction of light to a specific direction different from refraction by means of so-called Bragg diffraction, such as first-order diffraction and second-order diffraction. Among the emitted light, the light that cannot go out due to total reflection between layers or the like is diffracted by introducing a diffraction grating in one of the layers or in the medium (inside the transparent substrate or in the transparent electrode). , to bring the light out.
The diffraction grating to be introduced preferably has a two-dimensional periodic refractive index. This is because the light emitted from the light-emitting layer is randomly generated in all directions, so a general one-dimensional diffraction grating that has a periodic refractive index distribution in only one direction can only diffract light traveling in a specific direction. Therefore, 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 increased.
The position where the diffraction grating is introduced may be between any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but is preferably near 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 light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Condensing sheet》
The organic EL element in the present invention can be obtained by processing the light extraction side of the support substrate (substrate) so as to provide, for example, a microlens array structure, or by combining with a so-called light-condensing sheet. By condensing light in the front direction with respect to the light emitting surface, it is possible to increase the brightness in a specific direction.
As an example of the microlens array, square pyramids each having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably within the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction will occur and coloring will occur.

As the condensing sheet, it is possible to use, for example, a material that has been put to practical use in the LED backlight of the liquid crystal display device. For example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Co., Ltd. can be used as such a sheet. The shape of the prism sheet may be, for example, one in which delta-shaped stripes with an apex angle of 90 degrees and a pitch of 50 μm are formed on the base material, or a shape with rounded apex angles and a pitch that varies randomly. It may have a shape such as a square shape or other shapes.
In addition, a light diffusing plate/film may be used together 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.

《Application》
The organic EL element in the present invention can be used as display devices, displays, and various light emitting sources.
Examples of light sources include lighting devices (home lighting, vehicle interior lighting), backlights for clocks and liquid crystals, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, and light sources. Examples include, but are not limited to, light sources for sensors, and can be effectively used particularly as backlights for liquid crystal display devices and light sources for illumination.
In the organic EL element of the present invention, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation, if necessary. In the case of patterning, only the electrodes may be patterned, the electrodes and the light-emitting layer may be patterned, or the entire layer of the device may be patterned. can be done.

<<One Mode of Lighting Device>>
An embodiment of a lighting device equipped with an organic EL element according to the present invention will be described.
The non-light-emitting surface of the organic EL element 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 (Luxtrack LC0629B manufactured by Toagosei Co., Ltd.) is used as a sealing material around the periphery. ) 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 and sealed to form a lighting device as shown in FIGS. can be formed.
FIG. 1 shows a schematic diagram of a lighting device, in which an organic EL element 101 according to the present invention is covered with a glass cover 102 (the sealing operation with the glass cover is performed by exposing the organic EL element 101 to the atmosphere). was carried out in a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas with a purity of 99.999% or more)).
FIG. 2 shows a cross-sectional view of the lighting device, in which 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The inside of the glass cover 102 is filled with nitrogen gas 108 and a water capturing agent 109 is provided.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. The compounds used in the examples are A-1 to A-5 described above.

[Example 1]
The proton NMR of each solution 1-1 to 1-12 prepared by the following procedure was measured, and a comparison was made to see if there was a change in the chemical shift value of each peak of the solution. Here, the solvent containing the organic solvent Y was designated as component 1, and the solvent containing the active hydrogen compound was designated as component 2.

<Preparation of mother liquor W>
140 μmol of cyclohexane (=comparative solvent of component 2) was added to deuterated chloroform (=component 1) to make a total volume of 1.0 mL, and ultrasonic treatment was performed for 30 seconds to obtain mother liquor W.

<Preparation of mother liquor X>
A mother liquor X was obtained in the same manner as in the preparation of the mother liquor W, except that toluene (=the solvent of the present invention in component 2) was used instead of cyclohexane.

<Preparation of mother liquor Y>
A mother liquor Y was obtained in the same manner as in the preparation of the mother liquor W, except that TFPO was used instead of cyclohexane.

<Preparation of mother liquor Z>
A mother liquor Z was obtained in the same manner as in the preparation of the mother liquor W, except that OFPO was used instead of cyclohexane.

<Preparation of solution 1-1>
0.1 mL of the mother liquor W was mixed with 0.6 mL of deuterated chloroform and subjected to ultrasonic treatment for 30 seconds to obtain a solution 1-1.

<Preparation of solution 1-2>
10 mg of Compound A-1 was added to deuterated chloroform to a total of 0.6 mL and sonicated for 30 seconds. After that, 0.1 mL of the mother liquor W was added, and ultrasonic treatment was performed again for 30 seconds to obtain a solution 1-2.

<Preparation of solution 1-3>
A solution 1-3 was obtained in the same manner as in the preparation of the solution 1-2 except that the compound A-1 was changed to the compound A-2.

<Preparation of solutions 1-4 to 1-12>
Solutions 1-4 to 1-12 were obtained in the same manner as in the preparation of solution 1-1 except that the mother liquor (component 2) and the compound were changed as shown in Table I.

From the results shown in Table I, the results of proton NMR measurement of each solution 1-1 to 1-12 showed that each chemical shift shifted to the low magnetic field side when a solvent having active hydrogen was used.
It is generally known that the electron density of protons becomes low when they are attracted to atoms with high electronegativity, and they move to the low magnetic field side. Therefore, in the configuration of the present invention, hydrogen bonds are formed. It was inferred.

[Example 2]
After adding each nitrogen-containing aromatic heterocyclic compound to toluene (organic solvent Y, here, component 1), each different solvent (here, component 2. Component 2 contains an active hydrogen compound. .) was further added to the solutions 2-1 to 2-12, and the state was observed. In Table II below, ◯ indicates that the solution became transparent and had improved solubility compared to before the addition of component 2, Δ indicates that the solution was dissolved after standing for one day, and x indicates that no change was observed. It was shown to.

<Preparation of solution 2-1>
0.5 mL of toluene (component 1) was added to 2.5 mg of compound A-1. Then, the solution was subjected to ultrasonic treatment for 30 seconds, heated at 70° C. for 1 minute, and allowed to stand still for 1 hour.

<Preparation of solution 2-2>
After adding 0.5 mL of toluene to 2.5 mg of compound A-1, TFPO (component 2) was added so as to have a 20-fold molar number relative to the compound. Subsequently, the solution was subjected to ultrasonic treatment for 30 seconds, heated at 70° C. for 1 minute, and allowed to stand still for 1 hour.

<Preparation of solutions 2-3 to 2-6>
Solutions 2-3 to 2-6 were obtained in the same manner as in the preparation of solution 2-2, except that component 2 was replaced with one shown in Table II.

<Preparation of solutions 2-7 to 2-12>
Solutions 2-7 to 2-12 were obtained in the same manner, except that compound (A-1) in each of the solutions 2-1 to 2-6 was entirely replaced with A-2.

In solutions 2-2 and 2-3 to which an active hydrogen compound was added as component 2, precipitation of the compound was significantly reduced and improved solubility was observed compared to solution 2-1. Further, in the solution 2-4, precipitation was observed immediately after the addition of the solvent component 2, but when the solution was observed after standing for one day, an improvement in solubility was confirmed. On the other hand, the compound precipitated in solution 2-5 and solution 2-6 to which tetrahydrofuran (THF) and DME (dimethyl glycol) were added.
Almost the same results were obtained when the compound was replaced with A-2 from A-1. It was confirmed that the precipitation of the compound was small in the case of
Therefore, when even a small amount of an active hydrogen compound, which was confirmed to form a hydrogen bond by being mixed with a nitrogen-containing aromatic heterocyclic compound in Example 1, was included in the solution, the solubility was improved, and thus it could not be used conventionally. This indicates the possibility of using solvent species that were not previously available as coating solvents. Furthermore, at this time, it was confirmed that when the solvent of component 2 was contained in an amount of 1% by mass or more with respect to the total amount of solvent, it was dissolved.

[Example 3]
A solution obtained by adding each compound to a solvent was compared in terms of influence on the head and solubility by the following evaluation method.
<Preparation of solution 3-1>
Solution 3-1 was prepared so as to have the following mass composition ratio.
・8-Hydroxyquinolinolatritium 0.05%
・ Compound A-3 (nitrogen-containing aromatic heterocyclic compound) 0.52%
・Cesium acetate 0.03%
・ Ethyl propionate (component 1: organic solvent Y) 49.7%
・ OFPO (component 2: active hydrogen compound) 49.7%

<Preparation of solutions 3-2 to 3-45>
Solution 3-1 was prepared in the same manner except that the types and composition ratios of the nitrogen-containing aromatic heterocyclic compound, Component 1 and Component 2 were changed as shown in Tables III and IV below. 2-3-45 were obtained.

[evaluation]
<Injection stability>
Each solution obtained above was filled in a piezo inkjet printer head "KM1024i" (number of nozzles: 1024) manufactured by Konica Minolta, Inc., and continuously ejected for 1 minute, after which the nozzle surface of the inkjet printer head was opened. and allowed to stand for 2 minutes. Next, the solution was re-injected from the head, and the number of nozzles with missing nozzles or oblique injection due to nozzle clogging was counted, and injection stability was evaluated according to the following criteria.
(Evaluation criteria)
◎: No nozzle missing or oblique ejection occurred in all nozzles ○: Slight nozzle missing or oblique ejection was observed in nozzles 1 to 5, but there was no practical problem △: Mild ejection in nozzles 6 to 10 Missing nozzles and oblique ejection are observed, but there is no practical problem ×: More than 10 nozzles are missing nozzles or oblique ejection, making it difficult to use

<Material Compatibility>
Using "EP300" manufactured by Cemedine Co., Ltd., which is a two-liquid mixed type epoxy resin, 0.5 g of each of the main agent and the curing agent are collected and kneaded on a glass substrate having releasability at a ratio of 1:1. Then, heat curing was performed in an oven at 40° C. for 12 hours. After that, the mass at the time of peeling from the glass substrate was measured, and this was defined as mass 1.
Then, 1.0 g of the resin obtained above was immersed in 50 g of each of the above solutions and stored in a sealed state in an oven at 60° C. for 7 days. Thereafter, the resin sample for evaluation was taken out, thoroughly washed with 2-propanol, dried, and the weight of the resin sample for evaluation after the treatment was measured.
The rate of change X (relative value) of mass 2 when mass 1 obtained as described above was taken as 100% was calculated, and member compatibility was evaluated according to the following criteria. Note that X is an absolute value.
(Evaluation criteria)
◎: X<2.0%
○: 2.0% ≤ X < 5.0%
△: 5.0≦X<10.0%
×: 10.0% ≤ X

<Solubility>
Each solution obtained above was prepared in a vial so that the total volume was 3.0 mL, heated at 70 ° C. and then sealed with a lid. Visually observe the state of the solution again after 12 hours. , solubility was evaluated according to the following criteria.
(Evaluation criteria)
○: No precipitate is observed in the solution, or even if there is a precipitate, it is fine, and the solution is transparent ×: The nitrogen-containing aromatic heterocycle is not dissolved, and a large amount of precipitate is left after standing for 12 hours. can be seen

From the above results, when the ratio of the active hydrogen compound to the total mass of the solvent is 40% by mass or less, preferably 10% by mass or less, the nitrogen-containing aromatic heterocyclic compound dissolves in the solvent but does not damage the inkjet head. I found out. Therefore, it can be judged that the mixed composition having the structure of the present invention is a coating liquid that can be suitably used in the coating method.

INDUSTRIAL APPLICABILITY The present invention can be applied to a mixed composition for an organic electroluminescence device capable of improving the solubility of a solute in a solvent.

101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with transparent electrode 108 Nitrogen gas 109 Water capturing agent

Claims (6)

A mixed composition for an organic electroluminescence device containing an active hydrogen compound, a nitrogen-containing aromatic heterocyclic compound and an organic solvent Y,
At least one of the signals of the active hydrogen compound assigned using proton NMR is at a lower magnetic field in the presence of the nitrogen-containing heterocyclic compound than in the system in which the nitrogen-containing heterocyclic compound is not present. is shifted to the side, and
The organic solvent Y is liquid at room temperature ,
The nitrogen-containing aromatic heterocyclic compound has a structure represented by the following general formula (1), and
A mixed composition for an organic electroluminescence device, wherein the active hydrogen compound has a structure represented by the following general formula (2) .

[In general formula (1), ring A1 formed with =N- represents a 2-pyridine ring. Ar is a benzene ring ortho-positioned to the 2-pyridine ring, and further has a pyridine ring ortho-positioned to the benzene ring. R represents a substituent. n represents an integer of 0 or 1 or more. ]
General formula (2): HX
[In general formula (2), X represents a functional group. H represents a hydrogen atom that shifts downfield in proton NMR. ] The mixture for an organic electroluminescence device according to claim 1 , wherein the active hydrogen compound having a structure represented by the general formula (2) is an alcohol having a structure represented by the following general formula (2-1) Composition.
General formula (2-1): H—O—X′
[In general formula (2-1), X′ represents an optionally substituted hydrocarbon group. ] 3. The mixed composition for an organic electroluminescence device according to claim 1 , wherein said active hydrogen compound having a structure represented by said general formula (2) is a fluorinated alcohol. 4. The mixed composition for an organic electroluminescence device according to claim 1 , wherein the content of the active hydrogen compound is 40% by mass or less with respect to the total amount of solvent in the mixed composition. thing. The mixed composition for an organic electroluminescence device according to any one of claims 1 to 4 , wherein the content of the active hydrogen compound is 10% by mass or less with respect to the total amount of solvent in the mixed composition. thing. 6. The mixed composition for an organic electroluminescence device according to any one of claims 1 to 5 , wherein the organic solvent Y is an organic compound having no hydrogen atoms exhibiting hydrogen bonding properties.

Images