JP7060490B2 - Solutions for making nonionic organic electronics materials, electronic devices, organic electroluminescent devices and organic electroluminescent devices - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention relates to a nonionic organic electronic material, an electronic device, an organic electroluminescence element, and a solution for producing an organic electroluminescence element, and in particular, exhibits a deep blue light emission comparable to that of a conventional Ir-carbene complex, and is a complex. The present invention relates to a nonionic organic electronic material having a novel structure capable of improving the overall stability.

The organic electroluminescence device (hereinafter, also referred to as “organic EL device” or “OLED”) has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode. By applying an electric field to this, excitons are generated by recombination of holes injected from the anode and electrons injected from the cathode in the light emitting layer. It is a light emitting device that utilizes the emission of light (fluorescence / phosphorescence) when the excitons are deactivated.
Further, the organic EL element has already been commercialized as an electronic display or a flat light source for lighting, and is attracting attention and expected from the viewpoint of energy saving.
However, in reality, although the phosphorescence method with an emission quantum yield of almost 100% is applied for green and red emission, phosphorescence cannot achieve a sufficient life of the light emitting element in blue. It is only practical for some lighting, and all others are fluorescent.
Phosphorus emission is controlled by nonionic transition metal complexes such as iridium (Ir) and platinum (Pt), but blue emission has a HOMO-LUMO level gap more than other emission colors in terms of wavelength. It is necessary to increase the size, and in particular, the stability of the complex is directly linked to the life of the light emitting element.

In order to solve this problem, an Ir complex using a carbene ligand having a strong coordinating force has been studied, and the Ir-carbene complex disclosed in Patent Document 1 has a blue emission color. A cyano group is introduced to properly adjust the HOMO-LUMO level gap. However, in reality, this complex is not yet stable enough to be put into practical use for both lighting and display.

On the other hand, in Non-Patent Document 1, although a carbene metal complex having a tridentate ligand skeleton has been successfully synthesized, it is different from the use of phosphorescence.

International Publication No. 2007/088093

Zeitscrift furer anorganische und allgemeine Chemie, vol; 641, issu: 12-13, pages: 2199-2203

The present invention has been made in view of the above problems and situations, and the solution thereof is to exhibit deep blue light emission comparable to that of the conventional Ir-carbene complex and to improve the stability of the entire complex. It is to provide a nonionic organic electronic material having a novel structure capable of being capable. Another object of the present invention is to provide an electronic device, an organic electroluminescence device, and a solution for manufacturing an organic electroluminescence device using the nonionic organic electronics material.

In the process of examining the cause of the problem in order to solve the above-mentioned problems, the present inventor usually first stabilizes the Ir-carbene complex as disclosed in Patent Document 1. It was speculated that the best measure would be to exert an entropy effect by reducing the number of ligands for an Ir complex that requires three monovalent bidentate ligands. It is generally considered that the chelate complex is more stable than the monodentate coordination complex, and if the number of ligands of the same chelate complex can be reduced, the thermal stability of the chelate complex will be dramatically improved. However, it is not easy to achieve this with two ligands in an Ir complex with a stable trivalent 6-coordination, and no example of such an Ir complex being synthesized has been reported.
On the other hand, in the non-patent document 1, apart from the use of phosphorescent emission, a carbene metal complex having a tridentate ligand skeleton has been successfully synthesized, and the present inventor has succeeded in synthesizing the ligand by using the ligand. We have found the possibility of synthesizing a nonionic Ir complex with two asymmetric tridentate ligands. Then, by reducing the number of ligands as compared with the conventional Ir-carbene complex, that is, by forming an Ir complex composed of two types of tridental ligands, a deep blue light is emitted and the light is emitted. We have found that it is possible to provide an organic electronic material having excellent stability, and have arrived at the present invention.
That is, the above-mentioned problem according to the present invention is solved by the following means.

［式中、Ｒ^１～Ｒ^４は、各々独立にアルキル基、アリール基、複素環基、シアノ基又はフッ素原子を表す。ｎ^１～ｎ^４は、０～４の整数を表し、ｎ^１～ｎ^４が２以上の場合には、同一の置換基であっても異なる置換基であってもよく、置換基同士が互いに結合してもよい。Ｌ^１、Ｌ^２は、単結合又は連結基を表す。Ｑ^１～Ｑ^３は、各々独立に置換若しくは非置換の芳香族炭化水素環又は芳香族複素環を表す。Ａ^１～Ａ^３は、各々独立に炭素原子又は窒素原子を表し、Ａ^１～Ａ^３の少なくとも一つは炭素原子を表す。］ 1. 1. A nonionic organic electronic material having a structure represented by the following general formula (1).

[In the formula, R ¹ to R ⁴ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁴ represent an integer of 0 to 4, and when n ¹ to n ⁴ are 2 or more, they may be the same substituent or different substituents, and the substituents are mutually exclusive. May be combined. L ¹ and L ² represent a single bond or a linking group. ^Q1 to ^Q3 each represent an independently substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle. A ¹ to A ³ independently represent a carbon atom or a nitrogen atom, and at least one of A ¹ to A ³ represents a carbon atom. ]

［式中、Ｒ^１～Ｒ^７は、各々独立にアルキル基、アリール基、複素環基、シアノ基又はフッ素原子を表す。ｎ^１～ｎ^６は、０～４の整数を表し、ｎ^７は、０～３の整数を表し、ｎ^１～ｎ^７が２以上の場合には、同一の置換基であっても異なる置換基であってもよく、置換基同士が互いに結合してもよい。］ 2. 2. The nonionic organic electronic material according to item 1, wherein the structure represented by the general formula (1) is a structure represented by the following general formula (2).

[In the formula, R ¹ to R ⁷ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁶ represent an integer of 0 to 4, n ⁷ represents an integer of 0 to 3, and when n ¹ to n ⁷ are 2 or more, different substitutions are made even if they are the same substituent. It may be a group, or the substituents may be bonded to each other. ]

3. 3. An electronic device comprising the nonionic organic electronic material according to paragraph 1 or 2.

4. An organic electroluminescence device comprising the nonionic organic electronic material according to the first or second paragraph.

5. A solution for producing an organic electroluminescent device, which comprises the nonionic organic electronic material according to the first item or the second item.

By the above means of the present invention, a nonionic organic electronic material having a novel structure capable of exhibiting deep blue emission comparable to that of a conventional Ir-carbene complex and improving the stability of the entire complex can be obtained. It is possible to provide an electronic device, an organic electroluminescence device, and a solution for manufacturing an organic electroluminescence device using the nonionic organic electronics material.
Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.
In an Ir complex having a stable trivalent 6-coordination, a deep blue light is emitted by forming an Ir complex composed of two types of tridentate ligands as in the structure represented by the general formula (1). Moreover, it is possible to provide an organic electronic material having excellent stability.
Considering the complex formation reaction from a thermodynamic point of view, in the reaction of converting an iridium complex in which six monodentate ligands are coordinated into a polydentate (for example, tridentate) ligand, the whole system is molecularly free. It is considered that the degree increases, that is, the entropy increases, so that the free energy of Gibbs decreases, and a more stable complex can be obtained.
In other words, in the above conversion reaction, it is considered that the "chelating effect" due to the formation of a cyclic structure with the polydentate ligand and the iridium ion, that is, the formation of the chelate complex, contributes.
It is presumed that the iridium complex according to the present invention also has the same mechanism as the above mechanism.

Schematic diagram of lighting equipment Schematic diagram of lighting equipment

The nonionic organic electronic material of the present invention is characterized by having a structure represented by the general formula (1).
This feature is a technical feature common to or corresponding to each of the following embodiments.

As an embodiment of the present invention, it is preferable that the structure represented by the general formula (1) is a structure represented by the following general formula (2) in terms of steric stability after complex formation. ..

The organic electronic material of the present invention is suitably used for electronic devices, particularly organic electroluminescence devices.
Further, the organic electronic material of the present invention is suitably used as a solution for producing an organic electroluminescence device.

Hereinafter, the present invention, its constituent elements, and modes and embodiments for carrying out the present invention will be described. In addition, in this application, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.

[Overview of Nonionic Organic Electronics Material of the Present Invention]
The nonionic organic electronic material of the present invention (hereinafter, also simply referred to as "organic electronic material") is characterized by having a structure represented by the following general formula (1).

［式中、Ｒ^１～Ｒ^４は、各々独立にアルキル基、アリール基、複素環基、シアノ基又はフッ素原子を表す。ｎ^１～ｎ^４は、０～４の整数を表し、ｎ^１～ｎ^４が２以上の場合には、同一の置換基であっても異なる置換基であってもよく、置換基同士が互いに結合してもよい。Ｌ^１、Ｌ^２は、単結合又は連結基を表す。Ｑ^１～Ｑ^３は、各々独立に置換若しくは非置換の芳香族炭化水素環又は芳香族複素環を表す。Ａ^１～Ａ^３は、各々独立に炭素原子又は窒素原子を表し、Ａ^１～Ａ^３の少なくとも一つは炭素原子を表す。］ <Compound having a structure represented by the general formula (1)>

[In the formula, R ¹ to R ⁴ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁴ represent an integer of 0 to 4, and when n ¹ to n ⁴ are 2 or more, they may be the same substituent or different substituents, and the substituents are mutually exclusive. May be combined. L ¹ and L ² represent a single bond or a linking group. ^Q1 to ^Q3 each represent an independently substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle. A ¹ to A ³ independently represent a carbon atom or a nitrogen atom, and at least one of A ¹ to A ³ represents a carbon atom. ]

In the general formula (1), R ¹ to R ⁴ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a (t) butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a benzyl group and the like. Can be mentioned.
Examples of the aryl group (also referred to as an aromatic hydrocarbon group) include a phenyl group, a p-chlorophenyl group, a mesityl group, a tolyl group, a xylyl group, a naphthyl group, an anthryl group, an azulenyl group, an acenaphthenyl group and a fluorenyl group. Examples thereof include a phenanthryl group, an indenyl group, a pyrenyl group, and a biphenylyl group.
Examples of the heterocyclic group include an epoxy ring, an aziridine ring, a thiyrane ring, an oxetane ring, an azetidine ring, a thietan ring, a tetrahydrofuran ring, a dioxolan ring, a pyrrolidine ring, a pyrazoline ring, an imidazoline ring, an oxazolidine ring, and a tetrahydrothiophene ring. Sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactum ring, piperidine ring, hexahydropyrrolidine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4- Examples thereof include a dioxane ring, a trioxane ring, a tetrahydropyran ring, a thiomorpholine ring, a thiomorpholine 1,1-dioxide ring, a pyranose ring, and a diazabicyclo [2,2,2] -octane ring.

In the general formula (1), n ¹ to n ⁴ represent an integer of 0 to 4. When n ¹ to n ⁴ are 2 or more, the same substituents or different substituents may be used, and the substituents may be bonded to each other.

In the general formula (1), L ¹ and L ² represent a single bond or a linking group.
Examples of the linking group include a divalent linking group, and the divalent linking group is not particularly limited, but an alkylene group, an alkenylene group, an alkynylene group, O, (C = O), NR, S, and the like. Examples thereof include a divalent linking group selected from the group consisting of (O = S = O), a linking group in which two of them are combined, and the like.
In the general formula (1), Q ¹ to Q ³ represent independently substituted or unsubstituted aromatic hydrocarbon rings or aromatic heterocycles, respectively.
Examples of the aromatic hydrocarbon ring include those similar to the aryl group (aromatic hydrocarbon group) represented by R ¹ to R ⁴ .
Examples of the aromatic heterocycle include a pyridine ring, a pyrimidine ring, a furan ring, a pyrrole ring, an imidazole ring, a benzoimidazole ring, a pyrazole ring, a pyrazine ring, and a triazole ring (for example, 1,2,4-triazole, 1,2, 3-Triazole, etc.), oxazole ring, benzoxazole ring, thiazole ring, isooxazole ring, isothiazole ring, oxadiazole ring, thiophene ring, quinoline ring, benzofuran ring, dibenzofuran ring, benzothiophene ring, dibenzothiophene ring, indole. Ring, carbazole ring, carboline ring, diazacarbazole ring (indicating one in which one of the carbon atoms constituting the carboline ring is replaced with a nitrogen atom), quinoxaline ring, pyridazine ring, triazine ring, quinazoline ring, phthalazine ring, etc. Can be mentioned.
The substituents that the aromatic hydrocarbon ring or aromatic heterocycle may have include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a heterocyclic group and an aromatic complex. Ring group, halogen atom, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group , Carbamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group, amino group, nitro group, cyano group, hydroxy group, mercapto group, alkylsilyl group, arylsilyl group, alkylphosphino group, arylphosphino group, alkylphosphoryl Examples thereof include a group, an arylphosphoryl group, an alkylthiophosphoryl group and an arylthiophosphoryl group.

In the general formula (1), A ¹ to A ³ independently represent a carbon atom or a nitrogen atom, and at least one of A ¹ to A ³ represents a carbon atom.

［式中、Ｒ^１～Ｒ^７は、各々独立にアルキル基、アリール基、複素環基、シアノ基又はフッ素原子を表す。ｎ^１～ｎ^６は、０～４の整数を表し、ｎ^７は、０～３の整数を表し、ｎ^１～ｎ^７が２以上の場合には、同一の置換基であっても異なる置換基であってもよく、置換基同士が互いに結合してもよい。］ <Compound having a structure represented by the general formula (2)>
It is preferable that the structure represented by the general formula (1) is a structure represented by the following general formula (2) in terms of steric stability after complex formation.

[In the formula, R ¹ to R ⁷ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁶ represent an integer of 0 to 4, n ⁷ represents an integer of 0 to 3, and when n ¹ to n ⁷ are 2 or more, different substitutions are made even if they are the same substituent. It may be a group, or the substituents may be bonded to each other. ]

In the general formula (2), R ¹ to R ⁷ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively.
Examples of the alkyl group, aryl group and heterocyclic group include the same as the alkyl group, aryl group and heterocyclic group represented by R ¹ to R ⁴ of the general formula (1).

<Exemplified compound>
Hereinafter, specific examples of the compound having a structure represented by the general formula (1) and the general formula (2) according to the present invention will be shown, but the present invention is not limited thereto.

<Synthesis method>
The method for synthesizing the compound having the structure represented by the general formula (1) can be synthesized by the same method as the method for synthesizing the gold complex described in Non-Patent Document 1. Specifically, it can be synthesized according to the following scheme.

[Electronic device]
The organic electronic material of the present invention is suitably used for electronic devices as, for example, an organic electroluminescence material, an organic semiconductor material, an organic solar cell material, a photoelectric conversion material, and the like. That is, the electronic device of the present invention is characterized by containing the organic electronic material.
Examples of the electronic device include an organic electroluminescent element, an LED (Light Emitting Diode), a liquid crystal element, a solar cell, a touch panel, and the like.

[Organic EL element]
The organic EL element of the present invention is characterized by containing the organic electronic material.
Typical device configurations of the organic EL device manufactured by using the organic electronics material of the present invention include, but are not limited to, the following configurations.
(I) anode / light emitting layer / cathode (ii) anode / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / cathode (iv) anode / hole transport layer / light emitting 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) Anodic / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron injection layer / cathode Among the above, the configuration of (vii) is preferable. Used, but not limited to.

The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers. If necessary, a hole blocking layer (also referred to as a hole barrier layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the anode, and the light emitting layer and the anode may be provided. An electron blocking layer (also referred to as an electron barrier layer) or a hole injection layer (also referred to as an anode buffer layer) may be provided between them.
The electron transport layer according to the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Further, it may be composed of a plurality of layers.
The hole 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. Further, it may be composed of a plurality of layers.
In the above typical device configuration, the layer excluding the anode and the cathode is also referred to as an "organic layer".

(Tandem structure)
Further, the organic EL element of the present invention may be an element having a so-called tandem structure in which a plurality of light emitting units including at least one light emitting layer are laminated.
As a typical element configuration of the tandem structure, for example, the following configuration can be mentioned.
Anode / 1st light emitting unit / 2nd light emitting unit / 3rd light emitting unit / cathode Anode / 1st light emitting unit / intermediate layer / 2nd light emitting unit / intermediate layer / 3rd light emitting unit / cathode Here, the above 1st light emitting unit , The second light emitting unit and the third light emitting unit may all be the same or different. Further, the two light emitting units may be the same, and the remaining one may be different.
Further, the third light emitting unit may not be provided, while a light emitting unit or an intermediate layer may be further provided between the third light emitting unit and the electrode.

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

Examples of the material used for the intermediate layer include ITO (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 bilayer films, SnO ₂ / Ag / SnO ₂ , ZnO / Ag / Multilayer films such as ZnO, Bi ₂ O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO ₂ , and _fullerenes such as C60, conductive organic layers such as oligothiophene. , Metallic phthalocyanines, metal-free phthalocyanins, metal porphyrins, conductive organic compound layers such as metal-free porphyrins, etc., but the present invention is not limited thereto.

Preferred configurations in the light emitting unit include, for example, configurations excluding the anode and cathode from the configurations (i) to (vii) mentioned in the above typical element configurations, but the present invention is limited thereto. Not done.

Specific examples of the tandem organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Pat. No. 6,107,734, US Pat. No. 6,337,492, International. Publication No. 2005/009087, Japanese Patent Application Laid-Open No. 2006-228712, Japanese Patent Application Laid-Open No. 2006-24791, Japanese Patent Application Laid-Open No. 2006-49393, Japanese Patent Application Laid-Open No. 2006-49394, Japanese Patent Application Laid-Open No. 2006-49396, Japanese Patent Application Laid-Open No. 2011-96679, Kai 2005-340187, Japanese Patent No. 4711424, Japanese Patent No. 3496681, Japanese Patent No. 38845664, Japanese Patent No. 4213169, Japanese Patent Application Laid-Open No. 2010-192719, Japanese Patent Application Laid-Open No. 2009-0762929, Japanese Patent Application Laid-Open No. 2008-0784414, Japanese Patent Application Laid-Open No. 2007 Examples thereof include the element configurations and constituent materials described in Japanese Patent Application Laid-Open No. 059848, Japanese Patent Application Laid-Open No. 2003-272860, Japanese Patent Application Laid-Open No. 2003-04567, International Publication No. 2005/094130, etc., but the present invention is not limited thereto.

Hereinafter, each layer constituting the organic EL element of the present invention will be described.
《Light emitting layer》
The light emitting layer according to the present invention is a layer that provides a place where electrons and holes injected from an electrode or an adjacent layer are recombined and emit light via excitons, and the light emitting portion is a layer of the light emitting layer. It may be inside or at the interface between the light emitting layer and the adjacent layer. The structure of the light emitting layer according to the present invention is not particularly limited as long as it satisfies the requirements specified in the present invention.
The total thickness of the light emitting layer is not particularly limited, but the homogeneity of the formed layer, the prevention of applying an unnecessary high voltage at the time of light emission, and the improvement of the stability of the light emitting color with respect to the drive current are improved. From the viewpoint, it is preferably adjusted within the range of 2 nm to 5 μm, more preferably adjusted within the range of 2 to 500 nm, and further preferably adjusted within the range of 5 to 200 nm.
The thickness of each light emitting layer is preferably adjusted within the range of 2 nm to 1 μm, more preferably adjusted within the range of 2 to 200 nm, and further preferably adjusted within the range of 3 to 150 nm. ..

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

(1) Light-emitting dopant As the light-emitting dopant, a fluorescent light-emitting dopant (also referred to as a fluorescent dopant or a fluorescent compound) and a phosphorescent light-emitting 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 contains the organic electronic material (a compound having a structure represented by the general formula (1)).
The concentration of the light emitting dopant in the light emitting layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration with respect to the film thickness direction of the light emitting layer. It may have an arbitrary concentration distribution.
Further, the light emitting dopant according to the present invention may be used in combination of a plurality of types, may be used in combination of dopants having different structures, or may be used 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 shown in FIG. 4.16 on page 108 of the "New Color Science Handbook" (edited by the Japan Color Society, Tokyo University Press, 1985). It is determined by the color when the result measured by Konica Minolta Co., Ltd. is applied to the CIE chromaticity coordinates.
In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting dopants having different light emitting colors and exhibits white light emission.
The combination of light emitting dopants showing white color is not particularly limited, and examples thereof include a combination of blue and orange, a combination of blue and green and red, and the like.
The white color in the organic EL element according to the present invention is not particularly limited and may be white color closer to orange or white color closer to blue, but when the 2 degree viewing angle front luminance is measured by the above-mentioned method. In addition, it is preferable that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is within the region of x = 0.39 ± 0.09 and y = 0.38 ± 0.08.

(1.1) Phosphorescent Dopant A phosphorescent dopant according to the present invention (hereinafter, also referred to as “phosphorescent dopant”) will be described.
The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescent light at room temperature (25 ° C.), and has a phosphorescent quantum yield of 25. It is defined as a compound of 0.01 or more at ° C., but a preferable phosphorescence quantum yield is 0.1 or more.

The phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th edition Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescence dopant according to the present invention can achieve the above phosphorescence quantum yield (0.01 or more) in any of any solvents. Just do it.
There are two types of light emission of the phosphorescent dopant in principle. One is that carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. It is an energy transfer type that obtains light emission from a phosphorescent dopant. The other is a carrier trap type in which the phosphorescent dopant becomes a carrier trap, carriers are recombined on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. In either case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

As the phosphorescent dopant that can be used in the present invention, the organic electronics material (compound having a structure represented by the general formula (1)) can be used.
Further, in addition to the organic electronic material, a known material used for a light emitting layer of an organic EL element may be appropriately selected and used in combination.
Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.
Nature 395, 151 (1998), Appl. Phys. Let. 7
8, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Publication No. 2006/835469, US Patent Publication No. 2006/20202194, USA 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. Let. 86, 153505 (2005), Chem. Let. 34, 592 (2005), Chem. Commun. 2906 (2005), In
org. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Publication No. 2002/0034656, US Patent No. 7332232, US Patent Publication No. 2009/0108737, US Patent Publication No. 2009/00397776, US Patent No. 6921915, US Patent No. 6688266, US Patent Publication No. 2007/0190359, US Patent Publication No. 2006/0008670, US Patent Publication No. 2009/ 0165846, US Patent Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598, US Patent Publication No. 2006/0263635, US Patent Publication No. 2003/0158657, US Patent Publication No. 2003/0152802 , U.S. Pat. No. 7,090928, Angew. Chem. Int. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Apple. Phys. Let. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, U.S. Patent Publication No. 2006/0251923, U.S. Patent Publication No. 2005/02060441, U.S. Patent No. 7393599, U.S. Patent No. 7534505, U.S. Patent No. 7445855, U.S.A. Patent Publication No. 2007/0190359, US Patent Publication No. 2008/0297033, US Patent No. 7338722, US Patent Publication No. 2002/0134984, US Patent No. 7279704, US Patent Publication No. 2006/098120, US Patent Publication No. 2006/103874, International Publication No. 2005/0763880, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011 / 157339, International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/20327, International Publication No. 2011/05140
4, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Publication No. 2012/228583, US Patent Publication No. 2012/212126, JP2012-069737A, JP2012-195554 No., JP-A-2009-114086, JP-A-2003-81988, JP-A-2002-302671, JP-A-2002-363552, and the like.

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

(1.2) Fluorescent Luminous Dopant A fluorescent luminescent dopant according to the present invention (hereinafter, also referred to as “fluorescent dopant”) will be described.
The fluorescent dopant according to the present invention is a compound capable of emitting light from the excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.
Examples of the fluorescent dopant according to the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluorentene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes and coumarin derivatives. , Pyran derivative, cyanine derivative, croconium derivative, squalium derivative, oxobenzanthracene derivative, fluorescein derivative, rhodamine derivative, pyrylium derivative, perylene derivative, polythiophene derivative, rare earth complex compound and the like.

Further, in recent years, light emitting dopants using delayed fluorescence have also been developed, and these may be used.
Specific examples of the light emitting dopant using delayed fluorescence include the compounds described in International Publication No. 2011/156793, JP-A-2011-21364, JP-A-2010-93181, and the like. Is not limited to these.

(2) Host compound The host compound according to the present invention is a compound mainly responsible for charge injection and transport in the light emitting layer, and its own light emission is not substantially observed in the organic EL device.
A compound having a phosphorescent quantum yield of less than 0.1 at room temperature (25 ° C.) is preferable, and a compound having a phosphorescent quantum yield of less than 0.01 is more preferable. Further, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more.
Further, the excited state energy of the host compound is preferably higher than the excited state energy of the light emitting dopant contained in the same layer.

The host compound may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the transfer of electric charges, and it is possible 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 conventionally used in organic EL devices can be used. It may be a low molecular weight compound, a high molecular weight compound having a repeating unit, or a compound having a reactive group such as a vinyl group or an epoxy group.

As a known host compound, it has a hole transporting ability or an electron transporting ability, prevents the wavelength of light emission from being lengthened, and is stable against heat generation when the organic EL device is driven at a high temperature or while the device is being driven. It is preferable to have a high glass transition temperature (Tg) from the viewpoint of operating the device. Tg is preferably 90 ° C. or higher, and more preferably 120 ° C. or higher.
Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Calorimetry).

Specific examples of known host compounds used in the organic EL device in the present invention include, but are not limited to, the compounds described in the following documents.
Japanese Patent Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75445, 2002-338579, 2002. 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. 2003/01755553, US Patent Publication No. 2006/0280965, US Patent Publication No. 2005/0112407, US Patent Publication No. 2009/0017330, US Patent Publication No. 2009/0030202, US Patent Publication No. 2005 / 0238919, International Publication No. 2001/039234, International Publication No. 2009/021126, International Publication No. 2008/506746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/063796 No., International Publication No. 2007/063754, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/023947, Japanese Patent Application Laid-Open No. 2008-074939, Japanese Patent Application Laid-Open No. 2007-254297, EP2034538, and the like.

《Electron transport layer》
In the present invention, the electron transport layer may be made of a material having a function of transporting electrons and may have a function of transmitting electrons injected from the cathode to the light emitting layer.
The total film thickness of the electron transport layer in the present invention is not particularly limited, but is usually in the range of 2 nm to 5 μm, more preferably in the range of 2 to 500 nm, and further preferably in 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 any of electron injection property, electron transport property, and hole barrier property, and is available from among conventionally known compounds. Any one can be selected and used.
For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more of the carbon atoms constituting the carbazole ring substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, Triazine derivative, quinoline derivative, quinoxalin derivative, phenanthroline derivative, azatriphenylene derivative, oxazole derivative, thiazole derivative, oxadiazole derivative, thiadiazol derivative, triazole derivative, benzimidazole derivative, benzoxazole derivative, benzthiazole derivative, etc.), dibenzofuran derivative, Examples thereof include dibenzothiophene derivatives, silol derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

Further, metal complexes having a quinolinol skeleton or a dibenzoquinolinol skeleton as ligands, for example, 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 the above 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 an alkyl group, a sulfonic acid group, or the like can also be preferably used as an electron transport material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transporting material, and like the hole injection layer and the hole transporting layer, an inorganic semiconductor such as n-type-Si and n-type-SiC can be used. Can also be used as an electron transport material.
Further, it is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

In the electron transport layer according to the present invention, the electron transport layer may be doped with a doping material as a guest material to form a (electron-rich) electron transport layer having a high n property. Examples of the doping material include n-type dopants such as metal compounds and metal compounds such as 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. Mol. Apple. Phys. , 95, 5773 (2004) and the like.

Specific examples of known and preferable electron transporting materials used in the organic EL device according to the present invention include, but are not limited to, the compounds described in the following documents.
U.S. Patent No. 6528187, U.S. Patent No. 7230107, U.S. Patent Publication No. 2005/0025993, U.S. Patent Publication No. 2004/0036077, U.S. Patent Publication No. 2009/0115316, U.S. Patent Publication No. 2009/0101870, U.S. Patent Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/32085, Appl. Phys. Let. 75, 4 (1999), A
ppl. Phys. Let. 79, 449 (2001), Appl. Phys. Let. 81, 162 (2002), Appl. Phys. Let. 81, 162 (2002), Appl. Phys. Let. 79, 156 (2001), US Patent No. 7964293, US Patent Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/08537, International Publication No. 2006 / 067931, International Publication No. 2007/086552, International Publication No. 2008/114690, International Publication No. 2009/0694242, International Publication No. 2009/06679, International Publication No. 2009/054253, International Publication No. 2011/086953 No., International Publication No. 2010/150593, International Publication No. 2010/047707, EP23111826, JP-A-2010-251675, JP-A-2009-209133, JP-A-2009-124114, JP-A-2008-277810 Japanese Patent Application Laid-Open No. 2006-156445, Japanese Patent Application Laid-Open No. 2005-340122, Japanese Patent Application Laid-Open No. 2003-45662, Japanese Patent Application Laid-Open No. 2003-31367, Japanese Patent Application Laid-Open No. 2003-282270, International Publication No. 2012/115034 , Etc.

More preferable electron transporting materials in the present invention include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.
The electron transport material may be used alone or in combination of two or more.

《Hole blocking layer》
The hole blocking layer is a layer having the function of an electron transporting layer in a broad sense, and is preferably made of a material having a function of transporting electrons and a small ability to transport holes, and holes while transporting electrons. It is possible to improve the recombination probability of electrons and holes by blocking the above.
Further, the structure of the electron transport layer described above can be used as the hole blocking layer according to the present invention, if necessary.
The hole blocking layer 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, and more preferably in the range of 5 to 30 nm.
As the material used for the hole blocking layer, the material used for the electron transport layer described above is preferably used, and the material used as the host compound described above is also preferably used for the hole blocking layer.

《Electron injection layer》
The electron injection layer (also referred to as “cathode buffer layer”) according to the present invention is a layer provided between the cathode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and is referred to as “organic EL element and its light emitting layer”. It is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "Forefront of Industrialization (Published by NTS, November 30, 1998)".
In the present invention, the electron injection layer may be provided as needed and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.
The electron injection layer is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Further, it may be a non-uniform film in which the constituent material is intermittently present.

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

《Hole transport layer》
In the present invention, the hole transport layer may be made of a material having a function of transporting holes and may have a function of transmitting holes injected from the anode to the light emitting layer.
The total film 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, and further 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 any of hole injection property, hole transport property, and electron barrier property, and is among conventionally known compounds. Any one can be selected and used from.
For example, porphyrin derivative, phthalocyanine derivative, oxazole derivative, oxadiazole derivative, triazole derivative, imidazole derivative, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, hydrazone derivative, stilben derivative, polyarylalkane derivative, triarylamine derivative, carbazole derivative. , Indrocarbazole derivative, isoindole derivative, acene derivative such as anthracene and naphthalene, fluorene derivative, fluorenone derivative, and polyvinylcarbazole, a polymer material or oligomer in which an aromatic amine is introduced into the main chain or side chain, polysilane, conductivity. Examples thereof include sex polymers or oligomers (eg, PEDOT: PSS, aniline-based copolymers, polyaniline, polythiophene, etc.).

Examples of the triarylamine derivative include a benzidine type typified by α-NPD, a starburst type typified by MTDATA, and a compound having fluorene or anthracene in the triarylamine connecting core portion.
Further, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.
Further, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175. Apple. Phys. , 95, 5773 (2004) and the like.
Further, Japanese Patent Application Laid-Open No. 11-251067, J. Mol. Hung et. al. So-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC, as described in the authored literature (Applied Physics Letters 80 (2002), p. 139), can also be used. Further, an orthometalated organometallic complex having Ir or Pt in the central metal as typified by Ir (ppy) ₃ is also preferably used.
As the hole transport material, the above-mentioned materials can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organic metal complex, and an aromatic amine are introduced into the main chain or the side chain. High molecular weight materials or oligomers are preferably used.

Specific examples of known and preferable hole transporting materials used in the organic EL device according to the present invention include the compounds described in the following documents in addition to the above-mentioned documents, and the present invention includes these. Not limited.
For example, Appl. Phys. Let. 69, 2160 (1996), J. Mol. Lumin. 72-74, 985 (1997), Appl. Phys. Let. 78, 673 (2001), Appl. Phys. Let. 90, 183503
(2007), Appl. Phys. Let. 90, 183503 (2007)
, Apple. Phys. Let. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997)
), Synth. Met. 111,421 (2000), SID SymposiumDigest, 37, 923 (2006), J. Mol. 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 Publication No. 2007/002683, International Publication No. 2009/01809, EP650955, US Patent Publication No. 2008/01245772, US Patent Publication No. 2007/02789938, US Patent Publication No. 2008/0106190, US Patent Publication No. 2008/ No. 0018221,
International Publication No. 2012/11534, Japanese Patent Application Laid-Open No. 2003-591432, Japanese Patent Application Laid-Open No. 2006-135145, US Patent Application No. 13/585981, and the like.
The hole transporting material may be used alone or in combination of two or more.

《Electronic blocking layer》
The electron blocking layer is a layer having a function of a hole transporting layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, and is composed of a material having a small ability to transport electrons while transporting holes. It is possible to improve the recombination probability of electrons and holes by blocking the above.
Further, the structure of the hole transport layer described above can be used as an electron blocking layer according to the present invention, if necessary.
The electron blocking layer is preferably provided adjacent to the anode side of the light emitting layer.
The film thickness of the electron blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.
As the material used for the electron blocking layer, the material used for the hole transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the electron blocking layer.

《Hole injection layer》
The hole injection layer (also referred to as “anode buffer layer”) 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 emission brightness, and is referred to as an “organic EL element”. It is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "The Forefront of Industrialization (Published by NTS, November 30, 1998)".
In the present invention, the hole injection layer may be provided as needed and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.

The details of the hole injection layer are described in JP-A-9-45479, 9-2660062, 8-288609, etc., and examples of the material used for the hole injection layer include. Examples thereof include materials used for the hole transport layer described above.
Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in Japanese Patent Laid-Open No. 2003-591432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon, polyaniline (emeral). Conductive polymers such as din) and polythiophene, orthometallated complexes typified by tris (2-phenylpyridine) iridium complexes, triarylamine derivatives and the like are preferred.
The material used for the hole injection layer described above may be used alone or in combination of two or more.

<< Ingredients >>
The organic layer in the present invention described above may further contain other inclusions.
Examples of the inclusions include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals and alkaline earth metals such as Pd, Ca and Na, compounds and complexes of transition metals, salts and the like.
The content of the content can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 50 ppm or less, based on the total mass% of the contained layer. ..
However, it is not within this range depending on the purpose of improving the transportability of electrons and holes and the purpose of favoring the energy transfer of excitons.

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

For the anode, a thin film may be formed by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 μm or more). The pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.
Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can also be used. When emitting light from this anode, it is desirable to increase the transmittance to more than 10%, and the sheet resistance as the anode is several hundred Ω / sq. The following is preferable.
The film thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

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

The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance 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 transmit the emitted light, it is preferable that either the anode or the cathode of the organic EL element is transparent or translucent because the emission brightness is improved.
Further, a transparent or translucent cathode can be produced by producing the above metal on the cathode having a thickness of 1 to 20 nm and then producing the conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture an element in which both the anode and the cathode have transparency.

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

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate. CAP), cellulose ester phthalates, cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, Arton (trade name: JSR) or Appel. Examples thereof include cycloolefin-based resins (trade name: manufactured by Mitsui Kagaku Co., Ltd.).

A film of an inorganic substance, an organic substance, or a hybrid film thereof may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , 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 according to JIS K 7126-1987. A high barrier film having a transmittance 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 may be used as long as it has a function of suppressing the infiltration of a material that causes deterioration of the element such as moisture and oxygen, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used. Further, in order to improve the vulnerability of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The stacking order of the inorganic layer and the organic layer is not particularly limited, but it is preferable to stack the inorganic layer and the organic layer alternately a plurality of times.

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

Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films and opaque resin substrates, and ceramic substrates.
The quantum efficiency of light emission of the organic EL device according to the present invention at room temperature is preferably 1% or more, more preferably 5% or more.
Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons passed through the organic EL element × 100.
Further, a hue improving filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors by using a phosphor may be used in combination.

<Method of manufacturing organic EL element>
A method for forming an organic layer (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 a conventionally known forming method such as a vacuum vapor deposition method or a wet method (also referred to as a wet process) can be used, and when the organic electronic material of the present invention is used, the organic layer is formed. , It is preferable to use a wet method.
As the wet method, for example, in addition to printing methods such as gravure printing method, flexographic printing method, screen printing method, spin coating method, casting method, inkjet printing method, die coating method, blade coating method, bar coating method, roll coating method, etc. There are dip coating method, spray coating method, curtain coating method, doctor coating method, LB method (Langmuir-Blogjet method), etc., but the coating liquid can be applied easily and accurately, and it is highly productive. Therefore, it is more preferable to apply by an inkjet printing method using an inkjet head.

Further, a different film forming method may be applied to each layer. When a thin-film deposition method is used for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally the boat heating temperature is 50 to 450 ° C, the vacuum degree is ^10-6 to ^10-2 Pa, and the vapor deposition rate is 0.01 to. It is desirable to appropriately select in the range of 50 nm / sec, substrate temperature -50 to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.
The formation of the organic layer in the present invention is preferably carried out consistently from the hole injection layer to the cathode by one vacuuming, but it may be taken out in the middle and a different film forming method may be applied. In that case, it is preferable to carry out the work in a dry inert gas atmosphere.

《Inkjet head》
The inkjet heads applicable to the present invention are, for example, JP-A-2012-140017, JP-A-2013-010227, JP-A-2014-058171, JP-A-2014-097644, JP-A-2015-142979. 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. An inkjet head having the configuration described in the above 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 the liquid medium, or a dispersion liquid in which the material is dispersed in the liquid medium as a solid content. As a dispersion method, it can be dispersed by a dispersion method such as ultrasonic wave, high shear force dispersion or media dispersion.
The liquid medium is not particularly limited, and is, for example, a halogen-based solvent such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene, dichlorohexanone, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, n-. Ketone solvents such as propylmethylketone and cyclohexanone, aromatic solvents such as benzene, toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic solvents such as cyclohexane, decalin and dodecane, ethyl acetate, n-propyl acetate, n acetate. -Ester solvents such as butyl, methyl propionate, ethyl propionate, γ-butyrolactone, diethyl carbonate, ether solvents such as tetrahydrofuran and dioxane, amide solvents such as dimethylformamide and dimethylacetamide, methanol, ethanol and 1-butanol. , Alcohol-based solvent such as ethylene glycol, nitrile-based solvent such as acetonitrile and propionitrile, dimethyl sulfoxide, water or a mixed solution medium thereof and the like.
The boiling point of these liquid media is preferably a boiling point lower than the temperature of the drying treatment from the viewpoint of quickly drying the liquid medium, specifically in the range of 60 to 200 ° C, more preferably 80 to 180 ° C. Is within the range of.

The coating liquid contains a surfactant for the purpose of controlling the coating range and 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 the surfactant include anionic or nonionic surfactants from the viewpoint of the influence of water contained in the solvent, leveling property, wettability to the substrate f1 and the like. Specifically, the surfactants listed in International Publication No. 08/146681, JP-A-2-41308, etc., such as fluorine-containing activators, can be used.

Similar to the film thickness, the viscosity of the coating film can be appropriately selected depending on the function required as the organic layer and the solubility or dispersibility of the organic material. Specifically, for example, 0.3 to 100 mPa. It can be selected within the range of s.
The film thickness of the coating film can be appropriately selected depending on the function required as the organic layer and the solubility or dispersibility of the organic material, and specifically, can be selected in the range of, for example, 1 to 90 μm.
After forming the coating film by the wet method, it is possible to have a coating step of removing the above-mentioned liquid medium. The temperature of the drying step is not particularly limited, but it is preferable to perform the drying treatment at a temperature that does not damage the organic layer, the transparent electrode, or the base material. Specifically, it cannot be said unconditionally because it differs depending on the composition of the coating liquid and the like, but for example, the temperature can be set to 80 ° C. or higher, and the upper limit is considered to be a possible region up to about 300 ° C. The time is preferably about 10 seconds or more and 10 minutes or less. Under such conditions, drying can be performed quickly.

《Sealing》
Examples of the sealing means used for sealing the organic EL element include a method of adhering the sealing member, the electrode, and the support substrate with an adhesive. The sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.
Specific examples thereof include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.

In the present invention, a polymer film or a metal film can be preferably used because the organic EL element can be made into a thin film. Furthermore, the polymer film is JIS K.
Oxygen permeability measured by a method according to 7126-1987 is 1 × 10 ^-3 mL / m ² / 24h or less, and water vapor transmission rate (25 ± 0. 5 ° C., relative humidity (90 ± 2)%) is preferably 1 × 10 ^-3 g / (m ² / 24h) or less.

Sandblasting, chemical etching, etc. are used to process the sealing member into a concave shape.
Specific examples of the adhesive include acrylic acid-based oligomers, photocurable and thermosetting adhesives having a reactive vinyl group of methacrylic acid-based oligomers, and moisture-curable adhesives such as 2-cyanoacrylic acid ester. be able to. In addition, heat and chemical curing type (two-component mixing) such as epoxy type can be mentioned. Further, hot melt type polyamide, polyester and polyolefin can be mentioned. Further, a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.
Since the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealed portion, or printing may be performed as in screen printing.

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

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

In the gas phase and liquid phase, an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicone oil may be injected into the gap between the sealing member and the display region of the organic EL element. preferable. It is also possible to create a vacuum. Further, a hygroscopic compound can be enclosed inside.
Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.) and sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). , Metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (eg, barium perchlorate, etc.) Magnesium iodide, etc.) and the like, 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 sandwiched in order to increase the mechanical strength of the element. In particular, when the sealing is performed by the sealing film, the mechanical strength thereof is not necessarily high, so it is preferable to provide such a protective film and a protective plate. As the material that can be used for this, a glass plate, a polymer plate / film, a metal plate / film, etc. similar to those used for the sealing can be used, but the polymer film is lightweight and thin. It is preferable to use.

<< Technology for improving light extraction >>
The organic EL element in the present invention emits light inside a layer having a refractive index higher than that of air (within a refractive index 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 degree of light can be taken out. This is because light incident on the interface (intersection between the transparent substrate and air) at an angle θ equal to or higher than the critical angle causes total internal reflection and cannot be taken out to the outside of the element, and the transparent electrode or light emitting layer and the transparent substrate This is because the light causes total internal reflection, the light is waveguideed through the transparent electrode or the light emitting layer, and as a result, the light escapes toward the side surface of the element.

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

In the present invention, these methods can be used in combination with the organic EL element, but a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate and a transparent electrode layer. A method of forming a diffraction grating between any layer (including between the substrate and the outside world) of the light emitting layer can be preferably used.
When a medium with a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light emitted from the transparent electrode has a higher efficiency of being taken out to the outside as the refractive index of the medium is lower. Become.
In the present invention, by combining these means, it is possible to obtain an element having higher brightness or excellent durability.

Examples of the low refractive index layer include airgel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, it is preferable that the low refractive index layer has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.
Further, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because the effect of the low refractive index layer diminishes when the thickness of the low refractive index medium becomes about the wavelength of light and the film thickness of the electromagnetic wave exuded by evanescent enters the substrate.

The method of introducing a diffraction grating in an interface that causes total internal reflection or in any of the media is characterized by a high effect of improving the light extraction efficiency. This method is generated from the light emitting layer by utilizing the property that the diffraction lattice can change the direction of light to a specific direction different from the diffraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of the generated light, the light that cannot go out due to total reflection between the layers is diffracted by introducing a diffraction lattice into either layer or in the medium (inside the transparent substrate or transparent electrode). , Trying to get the light out.
It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because the light emitted by the light emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating that has a periodic refractive index distribution only in one direction, only the light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much.
However, by making the refractive index distribution a two-dimensional distribution, the light traveling in all directions is diffracted, and the light extraction efficiency is improved.
The position where the diffraction grating is introduced may be in any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but it is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of the light in the medium. As for the arrangement of the diffraction grating, it is preferable that the arrangement is repeated two-dimensionally, such as a square lattice shape, a triangular lattice shape, and a honeycomb lattice shape.

《Condensing sheet》
The organic EL element in the present invention is processed so as to provide a structure on a microlens array, for example, on the light extraction side of a support substrate (board), or by combining with a so-called condensing sheet, for example, an element in a specific direction. 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 a microlens array, a quadrangular pyramid having a side of 30 μm and an apex angle of 90 degrees is arranged two-dimensionally on the light extraction side of the substrate. One side is preferably in the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction is generated and it is colored, and if it is too large, the thickness becomes thick, which is not preferable.

As the light-collecting sheet, for example, a light-collecting sheet that has been put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a luminance increasing film (BEF) manufactured by Sumitomo 3M Ltd. can be used. The shape of the prism sheet may be, for example, a base material having a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or a shape having a rounded apex angle and a random pitch change. It may have a random shape or any other shape.
Further, a light diffusing plate / film may be used in combination with the light collecting sheet in order to control the light emission angle from the organic EL element. For example, a diffusion film (lighted up) manufactured by Kimoto Co., Ltd. can be used.

《Use》
The organic EL element in the present invention can be used as a display device, a display, and various light emitting sources.
As the light source, for example, a lighting device (household lighting, interior lighting), a backlight for a clock or a liquid crystal, a signboard advertisement, a signal, a light source for an optical storage medium, a light source for an electrophotographic copying machine, a light source for an optical communication processor, and light. Examples thereof include, but are not limited to, a light source of a sensor, but the light source can be effectively used as a backlight of a liquid crystal display device and a light source for illumination.
In the organic EL element of the present invention, if necessary, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned. In the production of the element, a conventionally known method is used. Can be done.

<< One aspect of lighting equipment >>
An aspect of the lighting device provided with the organic EL element in 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 (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) is used as a sealing material around the glass substrate. ) Is applied, this is placed on the cathode and brought into close contact with the transparent support substrate, UV light is irradiated from the glass substrate side, the curing is performed, and the sealing is performed. Can be formed.
FIG. 1 shows a schematic view of a lighting device, and the organic EL element 101 according to the present invention is covered with a glass cover 102 (note that the sealing operation with the glass cover brings the organic EL element 101 into contact with the atmosphere. It was performed in a glove box under a nitrogen atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).
FIG. 2 shows a cross-sectional view of a lighting device, in which 105 is a cathode, 106 is an organic EL layer, and 107 is a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108, and a water catching agent 109 is provided.

[Solution for manufacturing organic electroluminescence device]
The solution for producing an organic electroluminescence element of the present invention is characterized by containing the organic electronic material.
By containing the organic electronics material, the organic EL device manufactured by using the organic electroluminescence device manufacturing solution emits deep blue light, has excellent light emission efficiency and light emission life, has a low drive voltage, and has a low drive voltage. It is possible to suppress the voltage rise during driving and to have excellent stability over time.

The solution for producing an organic electroluminescence element of the present invention includes, for example, a printing method such as a gravure printing method, a flexographic printing method, and a screen printing method, as well as a spin coating method, a casting method, an inkjet printing method, a die coating method, and a blade coating method. It is applied by the bar coat method, roll coat method, dip coat method, spray coat method, curtain coat method, doctor coat method, LB method (Langmuir-Bloget method), etc. From the viewpoint of high accuracy and high productivity, it is more preferable to apply by an inkjet printing method using an inkjet head.

A method for dispersing an organic electroluminescence device manufacturing solution in a liquid medium, the type of liquid medium, a surfactant contained in the organic electroluminescence device manufacturing solution, and a coating film to which the organic electroluminescence device manufacturing solution is applied. The viscosity and the film thickness are as described in the section of "Method for manufacturing an organic EL element".

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in the examples, it represents "volume%" unless otherwise specified. Moreover, the exemplary compounds D-1 to D-40 used in the examples have a general formula (
Corresponds to D-1 to D-40 of specific examples of the compound having the structure represented by 1). Moreover, the structure of the comparative compound 1 used in the Example is shown.

[Example 1]
<< Fabrication of organic EL element 1-1 >>
Patterning was performed on a substrate (NA-45 manufactured by AvanStrate Inc.) in which ITO (indium tin oxide) was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate to a thickness of 100 nm. Then, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

This transparent support substrate is fixed to the substrate holder of a commercially available vacuum vapor deposition device, while 200 mg of HT-1 is put into a molybdenum resistance heating boat as a hole injection material, and HT- is used as a hole transport material in another molybdenum resistance heating boat. Add 200 mg of 2 and 200 mg of comparative compound 1 as a dopant in another molybdenum resistance heating boat, 200 mg of Host-1 as a host compound in another molybdenum resistance heating boat, and holes in another molybdenum resistance heating boat. 200 mg of ET-1 was put as a blocking material, and 200 mg of ET-2 as an electron transporting material was put in another molybdenum resistance heating boat and attached to a vacuum vapor deposition apparatus.

Next, after depressurizing the vacuum chamber to 4 × 10 ^-4 Pa, the heating boat containing HT-1 was energized and heated, and the film was vapor-deposited on a transparent support substrate at a vapor deposition rate of 0.1 nm / sec to a layer thickness of 10 nm. A hole injection layer was formed.

Further, the heating boat containing HT-2 was energized and heated, and vapor deposition was carried out on the hole injection layer at a vapor deposition rate of 0.1 nm / sec to form a hole transport layer having a layer thickness of 30 nm.

Further, the heating boat containing Comparative Compound 1 and Host-1 was energized and heated, and co-deposited on the hole transport layer at a vapor deposition rate of 0.1 nm / sec and 0.010 nm / sec, respectively, to a layer thickness of 40 nm. A light emitting layer was formed.

Further, the heating boat containing ET-1 was energized and heated, and vapor deposition was carried out on the light emitting layer at a vapor deposition rate of 0.1 nm / sec to form a hole blocking layer having a layer thickness of 10 nm.

Further, the heating boat containing ET-2 was energized and heated, and vapor deposition was carried out on the hole blocking layer at a vapor deposition rate of 0.1 nm / sec to form an electron transport layer having a layer thickness of 30 nm.

Subsequently, lithium fluoride was deposited on the electron transport layer to form an electron injection layer (cathode buffer layer) having a layer thickness of 0.5 nm, and aluminum was further deposited on the electron injection layer to have a thickness of 110.
An organic EL element 1-1 was manufactured by forming a cathode having a nm.
The compound used in this example has the following chemical structural formula.

<< Fabrication of organic EL elements 1-2 to 1-41 >>
In the production of the organic EL element 1-1, the organic EL elements 1-2 to 1-41 were produced in the same manner except that the comparative compound 1 was changed to the compounds shown in Table I.

<< Evaluation of organic EL elements 1-1 to 1-41 >>
When evaluating the obtained organic EL elements 1-1 to 1-41, the non-light emitting surface of each organic EL element after production is covered with a glass case, and a glass substrate having a thickness of 300 μm is used as a sealing substrate. An epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) is applied to the surroundings as a sealing material, which is layered on the cathode and brought into close contact with the transparent support substrate, and UV light is irradiated from the glass substrate side. It was cured and sealed to prepare a lighting device as shown in FIGS. 1 and 2.
The following evaluations were performed on each sample prepared in this way. The evaluation results are shown in Table I.

(1) External extraction quantum efficiency (also called luminous efficiency)
Using an organic EL element, lighting is performed under constant current conditions of room temperature (about 23 to 25 ° C.) and 2.5 mA / cm ² , and the emission brightness (L) [cd / m ² ] immediately after the start of lighting is measured. The external extraction quantum efficiency (η) was calculated.
Here, the emission luminance was measured using CS-1000 (manufactured by Konica Minolta), and the external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 as 100.

(2) Half-life The half-life was evaluated according to the measurement method shown below. Each organic EL element was driven with a constant current with a current giving an initial brightness of 1000 cd / m ² , and the time to become 1/2 of the initial brightness (500 cd / m ² ) was obtained, which was used as a measure of half life. The half-life was expressed as a relative value with the organic EL element 1-1 as 100.

(3) Drive voltage The voltage when the organic EL element is driven at room temperature (about 23 to 25 ° C.) and under constant current conditions of 2.5 mA / cm ² is measured, and the measurement results are as shown below. A relative value with the organic EL element 1-1 as 100 was obtained.
Drive voltage = (drive voltage of each element / drive voltage of organic EL element 1-1) × 100
The smaller the value, the lower the drive voltage as compared with the comparative example.

(4) Voltage rise during driving The voltage when the organic EL element is driven under constant current conditions of room temperature (about 23 to 25 ° C) and 2.5 mA / cm ² is measured, and the following calculation formula is used from the measurement results. The voltage rise during driving was calculated. The voltage rise during driving is represented by a relative value with the organic EL element 1-1 as 100.
Voltage increase during drive (relative value) = Drive voltage when luminance is halved-Initial drive voltage Note that the smaller the value, the smaller the voltage increase during drive compared to the comparative example.

(5) Stability over time The organic EL element was stored at 60 ° C. and 70% RH for one month, and the power efficiency before and after storage was determined. The power efficiency ratio was calculated from each power efficiency according to the following formula, and this was used as a measure of stability over time.
Stability over time (%) = (power efficiency after storage / power efficiency before storage) x 100
For power efficiency, the front luminance and luminance angle dependence of each organic EL element were measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta), and the one obtained at a front luminance of 1000 cd / m ² was used. board.

As is clear from Table I, the organic EL element using the compound having the structure represented by the general formula (1) is superior in luminous efficiency and emission lifetime and has a low drive voltage as compared with the organic EL element of the comparative example. It was also found that the voltage rise during driving was suppressed and the stability over time was excellent.

[Example 2]
<< Fabrication of organic EL element 2-1 >>
Patterning was performed on a substrate (NA-45 manufactured by AvanStrate Inc.) in which ITO (indium tin oxide) was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate to a thickness of 100 nm. Then, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

On this transparent support substrate, poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) diluted to 70% by mass with pure water was used at 3000 rpm. After forming a thin film by a spin coating method under the conditions of 30 seconds, it was dried at 200 ° C. for 1 hour to form a first hole transport layer having a layer thickness of 20 nm.

This substrate was transferred to a nitrogen atmosphere, and 47 mg of HT-3 and 3 mg of HT-4 were dissolved in 10 mL of toluene on the first hole transport layer under the conditions of 1500 rpm and 30 seconds. , A thin film was formed by the spin coating method. It was irradiated with ultraviolet light at 120 ° C. for 90 seconds, photopolymerized and crosslinked, and further vacuum dried at 60 ° C. for 1 hour to form a second hole transport layer having a layer thickness of about 20 nm.

A solution of 100 mg of Host-3, 20 mg of Comparative Compound 1, 0.5 mg of DG-1, and 0.2 mg of DR-1 dissolved in 10 mL of butyl acetate on the second hole transport layer. A thin film was formed by the spin coating method under the conditions of 600 rpm and 30 seconds. Further, it was vacuum dried at 60 ° C. for 1 hour to form a light emitting layer having a layer thickness of about 70 nm.

Next, a thin film was formed on this light emitting layer by a spin coating method under the conditions of 1500 rpm and 30 seconds using a solution of 50 mg of ET-3 in 10 mL of hexafluoroisopropanol (HFIP). Further, it was vacuum dried at 60 ° C. for 1 hour to form an electron transport layer having a layer thickness of about 20 nm.

Subsequently, this substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 × 10 ^-4 Pa, and then potassium fluoride is vapor-deposited on the electron transport layer to inject electrons having a layer thickness of 0.4 nm. A layer was formed, and further, aluminum was vapor-deposited on the electron-injected layer to form a cathode having a thickness of 110 nm, thereby producing an organic EL element 2-1.
The compound used in this example has the following chemical structural formula.

<< Fabrication of organic EL elements 2-2-41 >>
In the production of the organic EL element 2-1 the organic EL elements 2-2 to 2-41 were produced in the same manner except that the comparative compound 1 was changed to the compounds shown in Table II.

<< Evaluation of organic EL elements 2-1 to 2-41 >>
When the obtained organic EL element was evaluated, it was sealed in the same manner as the organic EL element 1-1 of Example 1, and a lighting device as shown in FIGS. 1 and 2 was produced and evaluated.
For each sample thus prepared, the external extraction quantum efficiency, half-life, driving voltage, and voltage increase during driving were evaluated in the same manner as in Example 1. The evaluation results are shown in Table II. The measurement results of the external extraction quantum efficiency, half life, driving voltage, and voltage rise during driving in Table II are expressed as relative values with the measured value of the organic EL element 2-1 as 100.

As is clear from Table II, the organic EL element using the compound having the structure represented by the general formula (1) according to the present invention is superior in luminous efficiency and emission lifetime and lower than the organic EL element of the comparative example. It was clear that it was the driving voltage, and it was also found that the voltage rise during driving was suppressed and the stability over time was excellent.

[Example 3]
<< Fabrication of organic EL element 3-1 >>
Patterning was performed on a substrate (NA-45 manufactured by AvanStrate Inc.) in which ITO (indium tin oxide) was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate to a thickness of 100 nm. Then, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

Spin on this transparent support substrate using a solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer Co., Ltd., Baytron P Al4083) diluted to 70% by mass with pure water. After forming a thin film by the coating method, it was dried at 200 ° C. for 1 hour to form a first hole transport layer having a layer thickness of 30 nm.

On this first hole transport layer, the hole transport material Poly (N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl)) benzidine (manufactured by American Dye Source Co., Ltd., ADS- A thin film was formed by the spin coating method using the chlorobenzene solution of 254). It was heated and dried at 150 ° C. for 1 hour to form a second hole transport layer having a layer thickness of 40 nm.

A thin film was formed on this second hole transport layer by a spin coating method using a butyl acetate solution of Host-3 as a host compound and D-1 as a dopant, and the layer was heated and dried at 120 ° C. for 1 hour. A light emitting layer having a thickness of 30 nm was formed.

A thin film was formed on this light emitting layer by a spin coating method using a 1-butanol solution of ET-4 as an electron transporting material, and an electron transporting layer having a layer thickness of 20 nm was formed.

This substrate was attached to a vacuum vapor deposition apparatus and the vacuum chamber was depressurized to 4 × 10 ^-4 Pa. Next, lithium fluoride was vapor-deposited on the electron transport layer to form an electron-injected layer having a layer thickness of 1.0 nm, and aluminum was vapor-deposited on the electron-injected layer to form a cathode having a thickness of 110 nm. -1 was produced.
The compound used in this example has the following chemical structural formula.

<< Fabrication of organic EL elements 3-2-3-40 >>
In the production of the organic EL element 3-1 the organic EL elements 3-2 to 3-40 were produced in the same manner except that the compound D-1 was changed to the compounds D-2 to D-40.

<< Evaluation of organic EL elements 3-1 to 3-40 >>
When the obtained organic EL element was evaluated, it was sealed in the same manner as the organic EL element 1-1 of Example 1, and a lighting device as shown in FIGS. 1 and 2 was produced and evaluated.
A lighting test was carried out on each sample prepared in this way, and it was confirmed that each device emits light well.

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

Claims (5)

A nonionic organic electronic material having a structure represented by the following general formula (1).

[In the formula, R ¹ to R ⁴ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁴ represent an integer of 0 to 4, and when n ¹ to n ⁴ are 2 or more, they may be the same substituent or different substituents, and the substituents are mutually exclusive. May be combined. L ¹ and L ² represent a single bond or a linking group. ^Q1 to ^Q3 each represent an independently substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle. A ¹ to A ³ independently represent a carbon atom or a nitrogen atom, and at least one of A ¹ to A ³ represents a carbon atom. ] The nonionic organic electronic material according to claim 1, wherein the structure represented by the general formula (1) is a structure represented by the following general formula (2).

[In the formula, R ¹ to R ⁷ independently represent an alkyl group, an aryl group, a heterocyclic group, a cyano group or a fluorine atom, respectively. n ¹ to n ⁶ represent an integer of 0 to 4, n ⁷ represents an integer of 0 to 3, and when n ¹ to n ⁷ are 2 or more, different substitutions are made even if they are the same substituent. It may be a group, or the substituents may be bonded to each other. ] An electronic device comprising the nonionic organic electronic material according to claim 1 or 2. An organic electroluminescence device comprising the nonionic organic electronic material according to claim 1 or 2. A solution for producing an organic electroluminescence element, which comprises the nonionic organic electronic material according to claim 1 or 2.

Images