JP2010278390A - Organic electroluminescent device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device capable of obtaining high efficiency of luminescence and improved driving durability. <P>SOLUTION: The organic electroluminescent device includes at least one organic layer containing a light-emitting layer between an anode and a cathode. The light-emitting layer contains a host material and a specific iridium-based phosphorescent luminous material. A layer adjacent to the cathode of the light-emitting layer contains a compound expressed by general formula (4). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent device (hereinafter also referred to as “organic electroluminescent device” or “organic EL device”).

  Organic EL devices have features such as self-emission and high-speed response, and are expected to be applied to flat panel displays. In particular, organic thin films with hole transport properties (hole transport layers) and organic thin films with electron transport properties. Since the report of a two-layer type (laminated type) in which (electron transport layer) is laminated, it has attracted attention as a large-area light-emitting element that emits light at a low voltage of 10 V or less. The laminated organic EL device has a basic structure of positive electrode / hole transport layer / light emitting layer / electron transport layer / negative electrode, in which the light emitting layer is the hole transport layer as in the case of the two-layer type. Or you may make the said electron carrying layer serve as the function.

In such an organic EL element, various studies have been made in order to realize high luminous efficiency. For example, Patent Document 1 proposes a light-emitting element using an iridium-phenylquinoline (Ir-PQ) -based red phosphorescent material.
Patent Document 2 has at least one organic layer including a light emitting layer between a pair of electrodes, and contains at least one compound represented by the following general formula in any of the organic layers. An organic electroluminescent device has been proposed. It is described that the compound represented by the general formula is preferably contained in a layer adjacent to the light emitting layer, and that an iridium complex phosphorescent material is preferably contained in the light emitting layer.
However, R < ¹ > -R < ⁸ > represents either a hydrogen atom or a substituent, respectively. A represents an aromatic ring, and the aromatic ring may be substituted with a substituent. m represents an integer of 2 or more. n represents an integer of 1 or more.

  However, in the organic electroluminescent device using the iridium (Ir) red phosphorescent material such as the iridium-phenylquinoline (Ir-PQ) type or the iridium-phenylisoquinoline (Ir-PIQ) type of the prior art document, Holes and electrons do not contribute to recombination from the layer, and do not stay in the light emitting layer and may escape, resulting in a decrease in light emission efficiency. Further, when at least one of a hole blocking layer and an electron blocking layer is provided adjacent to the light emitting layer, there is a problem that driving durability is deteriorated.

Japanese Patent No. 3929689 US Patent Application Publication No. 2009/0072727

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a red organic electroluminescent device capable of improving high luminous efficiency and driving durability.

As a result of intensive studies by the present inventors in order to solve the above problems, an iridium-based red phosphorescent material such as iridium-phenylquinoline (Ir-PQ) or iridium-phenylisoquinoline (Ir-PIQ) is used for the light-emitting layer. It has been found that in an organic electroluminescent device using, the luminous efficiency and driving durability can be improved by using a specific charge blocking material for the adjacent layer of the light emitting layer.
Furthermore, the light emitting layer uses a double host in which a hole transporting host material and an electron transporting host material are used in combination, each transports holes and electrons, and emits lightly doped iridium red phosphorescent material. When is employed, since it has a high carrier transport property, holes and electrons may not stay in the light emitting layer and may escape, resulting in a decrease in light emission efficiency. Thus, it has been found that the luminous efficiency can be improved by providing a hole blocking layer and, if necessary, an electron blocking layer in the adjacent layer of the double-host light emitting layer.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> having at least one organic layer including a light emitting layer between an anode and a cathode;
The light emitting layer contains a host material and a phosphorescent light emitting material represented by any one of the following general formulas (1), (2) and (3),
A layer adjacent to the cathode side of the light emitting layer contains a compound represented by the following general formula (4).
However, in said general formula (1), (2) and (3), n represents the integer of 1-3. XY represents a bidentate ligand. Ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom. R ¹¹ represents a substituent, and m1 represents an integer of 0 to 6. When m1 is 2 or more, adjacent R ¹¹ may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹² represents a substituent, and m2 represents an integer of 0 to 4. When m2 is 2 or more, adjacent R ¹² may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹¹ and R ¹² may combine to form a ring that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and the ring may be further substituted with a substituent. Good.
However, in said general formula (4), R < ¹ > -R < ⁸ > represents either a hydrogen atom or a substituent, respectively. A represents an aromatic ring, and the aromatic ring may be further substituted with a substituent. m represents an integer of 2 or more. n represents an integer of 1 or more.
<2> The organic electroluminescent element according to <1>, wherein the layer adjacent to the anode side of the light emitting layer contains a compound represented by the following general formula (5).
In the general formula (5), R ²² represents a hydrogen atom or a substituent. R ²¹ represents a substituent. m3 represents an integer of 0 to 4.
<3> The organic electroluminescent element according to <1>, wherein the layer adjacent to the anode side of the light emitting layer contains a compound represented by the following general formula (6).
However, in the general formula (6), R ³¹ and R ³² each represent either a hydrogen atom or a substituent, and neither R ³¹ nor R ³² becomes an aryl group. R ³³ and R ³⁴ each represent a substituent. m4 and p each represents an integer of 0 to 4. Q represents a 6-membered ring.
<4> The organic electroluminescent element according to any one of <1> to <3>, wherein the host material is a compound having a carbazole skeleton.
<5> The organic electroluminescent element according to any one of <1> to <4>, wherein the host material is a platinum complex compound represented by the following general formula (7).
However, in said general formula (7), L < ¹ >, L < ² > and L < ³ > represent either a single bond and a coupling group, respectively. R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ each represent a hydrogen atom or a substituent. R ^a and R ^b each represent a substituent, and n and m each represent an integer of 0 to 3.

  ADVANTAGE OF THE INVENTION According to this invention, the conventional problem can be solved and the red organic electroluminescent element which can aim at the improvement of high luminous efficiency and drive durability can be provided.

FIG. 1 is a schematic view showing an example of the layer structure of the organic electroluminescent element of the present invention.

(Organic electroluminescent device)
The organic electroluminescent element of the present invention has at least one organic layer including a light emitting layer between an anode and a cathode, and further has other layers as necessary.

<Light emitting layer>
The light emitting layer contains a host material and a phosphorescent light emitting material, and further contains other components as necessary.

-Phosphorescent material-
The phosphorescent material is preferably a compound represented by any one of the following general formulas (1), (2) and (3).
However, in said general formula (1), (2) and (3), n represents the integer of 1-3. XY represents a bidentate ligand. Ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom. R ¹¹ represents a substituent, and m1 represents an integer of 0 to 6. When m1 is 2 or more, adjacent R ¹¹ may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹² represents a substituent, and m2 represents an integer of 0 to 4. When m2 is 2 or more, adjacent R ¹² may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹¹ and R ¹² may combine to form a ring that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and the ring may be further substituted with a substituent. .

  The ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and preferred examples include a 5-membered ring and a 6-membered ring. The ring may be substituted with a substituent.

XY represents a bidentate ligand, and a bidentate monoanionic ligand is preferably exemplified.
Examples of the bidentate monoanionic ligand include picolinate (pic), acetylacetonate (acac), dipivaloylmethanate (t-butyl acac), and the like.
Examples of the ligand other than the above include the ligands described on pages 89 to 91 of Lamansky et al., International Publication WO02 / 15645 pamphlet.

The substituent for R ¹¹ and R ¹² is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a halogen atom, an alkoxy group, an amino group, an alkyl group, a cycloalkyl group, a nitrogen atom or sulfur It represents an aryl group which may contain an atom, an aryloxy group which may contain a nitrogen atom or a sulfur atom, and these may be further substituted.
R ¹¹ and R ¹² may be bonded to each other adjacent to each other to form a ring that may contain a nitrogen atom, a sulfur atom, or an oxygen atom, and a 5-membered ring, a 6-membered ring, and the like are preferable. It is mentioned in. The ring may be further substituted with a substituent.

Specific examples of the compound represented by any one of the general formulas (1), (2), and (3) include, but are not limited to, the following compounds.

The content of the phosphorescent light emitting material is preferably 0.1% by mass to 30% by mass, and preferably 0.5% by mass to 20% by mass with respect to the total compound mass that generally forms the light emitting layer in the light emitting layer. More preferably, it is more preferably 1% by mass to 10% by mass.
If the content is less than 0.1% by mass, the luminous efficiency may be reduced, and if it exceeds 30% by mass, the luminous efficiency may be reduced due to association of the phosphorescent material itself.

-Host material-
As the host material, both an electron transporting host material and a hole transporting host material can be preferably used, and an electron transporting host material and a hole transporting host material may be used in combination.

--Hole-transporting host material--
The hole transporting host material is not particularly limited and may be appropriately selected depending on the intended purpose.For example, pyrrole, indole, carbazole, azaindole, azacarbazole, pyrazole, imidazole, polyarylalkane, pyrazoline, Pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin compound, polysilane compound, poly Examples thereof include (N-vinylcarbazole), aniline-based copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organic silanes, carbon films, or derivatives thereof.
Among these, indole derivatives, carbazole derivatives, azaindole derivatives, azacarbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives are preferable, and the indole skeleton, carbazole skeleton, azaindole skeleton, azacarbazole skeleton, or aromatic in the molecule Those having an aromatic group tertiary amine skeleton are more preferred, and compounds having a carbazole skeleton are particularly preferred.
In the present invention, a host material in which part or all of the hydrogen in the host material is replaced with deuterium can be used (Japanese Patent Application No. 2008-126130, Japanese Patent Application Publication No. 2004-515506).

Specific examples of such a hole transporting host material include, but are not limited to, the following compounds.

  The content of the hole transporting host material is preferably 10% by mass to 99.9% by mass, and preferably 20% by mass to 20% by mass with respect to the total compound mass generally forming the light emitting layer in the light emitting layer. 99.5 mass% is more preferable, and 30 mass%-99 mass% is still more preferable.

--- Electron transporting host material--
The electron transporting host material is preferably a platinum complex compound represented by the following general formula (7).
However, in said general formula (7), L < ¹ >, L < ² > and L < ³ > represent either a single bond and a coupling group, respectively. R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ each represent a hydrogen atom or a substituent. R ^a and R ^b each represent a substituent, and n and m each represent an integer of 0 to 3.

The linking group for L ¹ , L ² and L ³ is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an alkylene group (for example, a methylene group, a dimethylmethylene group, a diisopropylmethylene group, a diphenylmethylene group) , Ethylene group, tetramethylethylene group, etc.), alkenylene group (vinylene group, dimethylvinylene group, etc.), alkynylene group (ethynylene group, etc.), arylene group (phenylene group, naphthylene group, etc.), heteroarylene group (pyridylene group, pyrazirene group, etc.) Group, quinolylene group, etc.), oxygen linking group, sulfur linking group, nitrogen linking group (methylamino linking group, phenylamino linking group, t-butylamino linking group, etc.), silicon linking group, or a linking group combining these ( For example, an oxylenmethylene group and the like.

The substituents in R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ , and R ^a and R ^b are not particularly limited and are appropriately selected depending on the purpose. For example, an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably carbon number). 2-10, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl group (preferably charcoal) 2-30, more preferably 2-20 carbon atoms, particularly preferably 2-10 carbon atoms, such as propargyl, 3-pentynyl, etc.), aryl groups (preferably 6-30 carbon atoms, and more). Preferably it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl, anthranyl and the like, and an amino group (preferably having 0 to 30 carbon atoms, more preferably Has 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino and the like, and an alkoxy group (preferably carbon). 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms. Toxi, ethoxy, butoxy, 2-ethylhexyloxy, etc.), an aryloxy group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, For example, phenyloxy, 1-naphthyloxy, 2-naphthyloxy, etc.), a heterocyclic oxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), an acyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, For example, acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably Ku 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, and the like ethoxycarbonyl. ), An aryloxycarbonyl group (preferably having a carbon number of 7 to 30, more preferably a carbon number of 7 to 20, particularly preferably a carbon number of 7 to 12, such as phenyloxycarbonyl), an acyloxy group (preferably Has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetoxy and benzoyloxy.), An acylamino group (preferably 2 to 30 carbon atoms, More preferably, it has 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino, benzoylamino and the like, and an alkoxycarbonylamino group (preferably 2 to 30 carbon atoms, more preferably carbon atoms). 2 to 20, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino An aryloxycarbonylamino group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino). A sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino), a sulfamoyl group (Preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 12 carbon atoms. Examples thereof include sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and phenylsulfamoyl. ), A carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably A prime number of 1-20, particularly preferably a carbon number of 1-12, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc., an alkylthio group (preferably having a carbon number of 1-30, more preferably a carbon number). 1 to 20, particularly preferably 1 to 12 carbon atoms, for example, methylthio, ethylthio, etc.), arylthio groups (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably carbon atoms). And a heterocyclic thio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). Pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio Etc. ), A sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms such as mesyl and tosyl), a sulfinyl group (preferably carbon). 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 30 carbon atoms, more Preferably it is C1-C20, Most preferably, it is C1-C12, for example, ureido, methylureido, phenylureido etc. are mentioned), phosphoric acid amide group (preferably C1-C30, more preferably It has 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms. Examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group Group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom, specifically, for example, imidazolyl, pyridyl and quinolyl. , Furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms). Particularly preferably having 3 to 24 carbon atoms, such as trimethylsilyl, ), Silyloxy groups (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, such as trimethylsilyloxy, triphenylsilyloxy, etc. And the like. These substituents may be further substituted.
Among these, it is particularly preferable that at least one of R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ is either a phenyl group or a cyano group.

Examples of the platinum complex compound represented by the general formula (7) include, but are not limited to, the following compounds.

The content of the platinum complex compound represented by the general formula (7) is 5% by mass to 99.5% by mass with respect to the total compound mass generally forming the light emitting layer in the light emitting layer. 10 mass%-99.5 mass% is more preferable, 10 mass%-70 mass% is still more preferable.
If the content is less than 5% by mass, the effect of lowering the voltage may be reduced.

The light-emitting layer receives holes from an anode, a hole injection layer, or a hole transport layer when an electric field is applied, receives electrons from a cathode, an electron injection layer, or an electron transport layer, and recombines holes and electrons. It is a layer having a function of providing a field to emit light.
The light emitting layer is not particularly limited and can be formed according to a known method. For example, by a dry film forming method such as a vapor deposition method or a sputtering method, a wet coating method, a transfer method, a printing method, an ink jet method, or the like. It can form suitably.

  There is no restriction | limiting in particular in the thickness of the said light emitting layer, According to the objective, it can select suitably, 2 nm-500 nm are preferable, 3 nm-200 nm are more preferable from a viewpoint of luminous efficiency, and 10 nm-200 nm are still more preferable. The light emitting layer may be a single layer or two or more layers.

<Cathode side adjacent layer (hole blocking layer)>
The cathode side adjacent layer is an organic layer adjacent to the light emitting layer on the cathode side, and functions as a hole blocking layer that prevents holes transported from the anode side to the light emitting layer from passing through to the cathode side.

The cathode side adjacent layer contains a compound represented by the following general formula (4), and further contains other components as necessary.
However, in said general formula (4), R < ¹ > -R < ⁸ > represents either a hydrogen atom or a substituent, respectively. A represents an aromatic ring, and the aromatic ring may be substituted with a substituent. m represents an integer of 2 or more. n represents an integer of 1 or more.

Examples of the substituent represented by R ¹ to R ^8, not particularly limited and may be appropriately selected depending on the intended purpose, e.g., an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an amino group , Alkoxy group, aryloxy group, heterocyclic oxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl Group, alkylthio group, arylthio group, heterocyclic thio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen group, cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid Group, sulfino group, Piperazino group, an imino group, heterocyclic groups other than heteroaryl groups, silyl group, silyloxy group, such as a deuterium atom. These substituents may be further substituted with other substituents, and these substituents may be bonded to each other to form a ring or an oligomer compound or polymer compound described later.

  The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms. For example, methyl, ethyl, n-propyl, iso-propyl, n-butyl. Tert-butyl, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-octadecyl, n-hexadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, 1-adamantyl, trifluoromethyl, etc. Can be mentioned. In the present invention, the “carbon number” of a substituent such as an alkyl group includes the case where a substituent such as an alkyl group may be substituted by another substituent, and also includes the carbon number of the other substituent. Used in meaning.

  The alkenyl group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms. For example, vinyl, allyl, 1-propenyl, 1-isopropenyl, 1- Examples include butenyl, 2-butenyl, 3-pentenyl and the like.

  The alkynyl group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms. Examples thereof include ethynyl, propargyl, 1-propynyl, and 3-pentynyl. .

  The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Examples thereof include phenyl, o-methylphenyl, m-methylphenyl, and p-methyl. And phenyl, 2,6-xylyl, p-cumenyl, mesityl, naphthyl, anthranyl, and the like.

  The heteroaryl group preferably has 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Specifically, for example, imidazolyl , Pyrazolyl, pyridyl, pyrazyl, pyrimidyl, triazinyl, quinolyl, isoquinolinyl, pyrrolyl, indolyl, furyl, thienyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, azepinyl and the like.

  The amino group preferably has 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 10 carbon atoms. For example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenyl Examples include amino and ditolylamino.

  The alkoxy group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy, 2-ethylhexyloxy and the like. .

  The aryloxy group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Examples thereof include phenyloxy, 1-naphthyloxy, 2-naphthyloxy, and the like. Can be mentioned.

  The heterocyclic oxy group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy and the like.

  The acyl group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl.

  The alkoxycarbonyl group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms. Examples thereof include methoxycarbonyl and ethoxycarbonyl.

  The aryloxycarbonyl group preferably has 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonyl.

  The acyloxy group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms, and examples thereof include acetoxy and benzoyloxy.

  The acylamino group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino.

The alkoxycarbonylamino group preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino.

  The aryloxycarbonylamino group preferably has 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonylamino.

  The sulfonylamino group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfonylamino and benzenesulfonylamino.

  The sulfamoyl group preferably has 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 12 carbon atoms. For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfa For example, moile.

  The carbamoyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl.

  The alkylthio group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include methylthio and ethylthio.

  As said arylthio group, Preferably it is C6-C30, More preferably, it is C6-C20, Most preferably, it is C6-C12, for example, phenylthio etc. are mentioned.

  The heterocyclic thio group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms. For example, pyridylthio, 2-benzimidazolylthio, 2-benzoxazolyl Examples include luthio and 2-benzthiazolylthio.

  The sulfonyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include mesyl, tosyl, trifluoromethanesulfonyl, and the like.

  The sulfinyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfinyl and benzenesulfinyl.

  The ureido group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include ureido, methylureido, and phenylureido.

  The phosphoric acid amide group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms. Examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. .

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The heterocyclic group other than the heteroaryl group preferably has 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms. Examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically For example, piperidyl, morpholino, pyrrolidyl and the like can be mentioned.

  The silyl group preferably has 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms. For example, trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethyl-tert-butylsilyl, Examples thereof include dimethylphenylsilyl, diphenyl-tert-butylsilyl, triphenylsilyl, tri-1-naphthylsilyl, tri-2-naphthylsilyl and the like.

  The silyloxy group preferably has 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyloxy and triphenylsilyloxy.

Here, in the general formula (4), R ¹ ~R ⁸ are each independently a hydrogen atom, or an alkyl group, an aryl group, a heteroaryl group, may represent a silyl group, or a halogen atom.
When R ^{1 to} R ⁸ are alkyl groups, they can be bonded to the carbazole ring with 1 to 4 carbon atoms, preferably bonded to the ring with 2 to 4 carbon atoms, The carbon atom is more preferably bonded to the ring, and it is particularly preferable that the ring is bonded to the ring by a quaternary carbon atom. For example, the substituent bonded to the ring at a primary carbon atom is a methyl group, and the substituent bonded to the ring at a secondary carbon atom is an ethyl group or a benzyl group, and a tertiary carbon atom. The substituent bonded to the ring is an iso-propyl group or a diphenylmethyl group, and the substituent bonded to the ring at a quaternary carbon atom is a tert-butyl group, a 1-adamantyl group or a trityl group. It is done.

R ¹ , R ² , R ⁴ , R ⁵ , R ⁷ and R ⁸ are preferably an alkyl group, an aryl group and a hydrogen atom, more preferably an alkyl group and a hydrogen atom, and particularly preferably a hydrogen atom. is there.
R ³ and R ⁶ are preferably an alkyl group, an aryl group, a silyl group, a cyano group, and a hydrogen atom, more preferably an alkyl group, a silyl group, and a hydrogen atom, and particularly preferably a hydrogen atom.

A represents a hydrocarbon aromatic ring composed of a carbon atom and a hydrogen atom, and a heteroaromatic ring containing a hetero atom other than a carbon atom and a hydrogen atom, and may have a substituent, and a plurality of aromatic rings It may be condensed. A preferably represents an aromatic ring.
The hydrocarbon aromatic ring preferably has 6 to 30 carbon atoms, more preferably 6 to 14 carbon atoms, and particularly preferably 6 carbon atoms. Examples of the hydrocarbon aromatic ring include benzene, naphthalene, anthracene, phenanthrene, tetracene (naphthacene), pentacene, pyrene, coronene and the like.
The heteroaromatic ring preferably has 3 to 30 carbon atoms, more preferably 4 to 16 carbon atoms, and particularly preferably 5 to 12 carbon atoms.
Examples of the heteroaromatic ring containing only a nitrogen atom as the heteroatom include pyridine, pyrazine, pyrimidine, pyrrole, pyrazole, and imidazole, and examples of the condensed ring include benzimidazole, indole, and carbazole. It is done. Examples of the heteroaromatic ring containing an oxygen atom as a hetero atom include furan, oxazole, and isoxazole. Examples of the heteroaromatic ring containing a sulfur atom as a hetero atom include thiophene, thiazole, and isothiazole. Examples of the condensed ring include benzofuran, dibenzofuran, benzothiophene, and dibenzothiophene.
A preferably contains benzene, azines, pyrrole, furan, thiophene, more preferably contains benzene, pyridine, pyrazine, naphthalene, anthracene, indole, carbazole, dibenzofuran, dibenzothiophene, and benzene, pyridine. More preferably, benzene is particularly preferred.

m represents an integer of 2 or more, preferably 2 to 10, preferably 2 to 6, more preferably 2 to 5, and particularly preferably 2 to 3.
n represents an integer of 1 or more, preferably 1 to 10, more preferably 1 to 4, more preferably 1 to 3, and particularly preferably 1.

In the compound represented by the general formula (4), A represents an aromatic ring, m represents an integer of 2 to 5, n represents an integer of 1 to 4, and R ^{1 to} R ⁸ are each independently It preferably represents a hydrogen atom or an alkyl group, an aryl group, a heteroaryl group, a silyl group, or a halogen atom.
In the compound represented by the general formula (4), A represents a benzene ring, m represents an integer of 2 to 5, n represents an integer of 1 to 4, and m + n represents an integer of 3 to 6. It is preferable to represent.

The compound represented by the general formula (4) may be a low molecular compound, an oligomer compound, a polymer compound having a structure represented by the general formula (4) in the main chain or side chain (mass average) The molecular weight (in terms of polystyrene) is preferably 1,000 to 5,000,000, more preferably 2,000 to 1,000,000, and still more preferably 3,000 to 100,000. Good. The compound represented by the general formula (4) is preferably a low molecular compound.
When the compound represented by the general formula (4) is an oligomer compound or a polymer compound having a structure represented by the general formula (4) in a main chain or a side chain, the main chain is represented by R ^{1 to} R ⁸ . Plural groups or groups substituted on A are included, more preferably plural groups including any of R ³ and R ⁵ or groups substituted on A are included, and particularly preferably R ⁵ or A is substituted. Group. When included as a side chain, any one of R ^{1 to} R ⁸ or a group substituted with A is included, more preferably any of R ³ , R ⁵ or a group substituted with A is included. Particularly preferably, a group substituted with A is included.

  In the cathode side adjacent layer, the compound represented by the general formula (4) is preferably contained in an amount of 1% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and more preferably 80% by mass. More preferably, it is contained in an amount of ˜100 mass%.

  The compound represented by the general formula (4) can be synthesized from, for example, an aromatic halide having a cyano group. That is, in the case of chloride, bromide, and iodide, it can be synthesized by a coupling reaction of carbazole and a carbazole having a substituent with a catalyst containing a palladium compound or a copper compound. Can be synthesized by a substitution reaction with carbazole and an alkali metal salt of carbazole having a substituent.

Specific examples of the compound represented by the general formula (4) are listed below, but the present invention is not limited to these compounds. In the specific examples below, Cz represents an N-carbazolyl group.

Specific examples of the polymer compound and the oligomer compound are given below as the compound represented by the general formula (4), but the present invention is not limited to these compounds. In the case of a polymer compound, it may be a homopolymer compound or a copolymer, and the copolymer may be a random copolymer, an alternating copolymer, or a block copolymer. In formula, m: n represents the molar ratio of each monomer contained in a polymer, m represents 1-100, n represents the numerical value of 0-99, and the sum of m and n is 100. The polymerization degree of m is preferably 20 to 500, and more preferably 20 to 100.

The hole blocking layer as the cathode side adjacent layer is not particularly limited and can be formed according to a known method, for example, a vapor deposition method, a dry film forming method such as a sputtering method, a wet coating method, a transfer method, It can be suitably formed by a printing method, an inkjet method, or the like.
The thickness of the hole blocking layer is preferably 1 nm to 200 nm, more preferably 1 nm to 50 nm, and still more preferably 3 nm to 20 nm.

<Anode side adjacent layer (electronic block layer)>
The anode side adjacent layer is an organic layer adjacent to the light emitting layer on the anode side, and functions as an electron blocking layer that prevents electrons transported from the cathode side to the light emitting layer from passing to the anode side.

The anode side adjacent layer preferably contains a compound represented by the following general formula (5).
In the general formula (5), R ²² represents a hydrogen atom or a substituent. R ²¹ represents a substituent. m3 represents an integer of 0 to 4.

Examples of the substituent for R ²² include an aryl group such as an alkyl group and a phenyl group.
Examples of the substituent for R ²¹ include a halogen atom, an alkoxy group, an amino group, an alkyl group, a cycloalkyl group, an aryl group, and an aryloxy group, and these may be further substituted.

Specific examples of the compound represented by the general formula (5) are given below, but the present invention is not limited to these compounds.

Moreover, as said anode side adjacent layer, it is preferable to contain the compound represented by following General formula (6).
However, in the general formula (6), R ³¹ and R ³² each represent either a hydrogen atom or a substituent, and neither R ³¹ nor R ³² becomes an aryl group. R ³³ and R ³⁴ each represent a substituent. m4 and p each represents an integer of 0 to 4. Q represents a 6-membered ring.

Examples of the substituent for R ³¹ and R ³² include an aryl group such as an alkyl group and a phenyl group. Neither R ³¹ nor R ³² becomes an aryl group.
Examples of the substituent for R ³³ and R ³⁴ include a halogen atom, an alkoxy group, an amino group, an alkyl group, a cycloalkyl group, an aryl group, and an aryloxy group, and these may be further substituted.

Specific examples of the compound represented by the general formula (6) are listed below, but the present invention is not limited to these compounds.

The electron blocking layer as the anode side adjacent layer is not particularly limited and can be formed according to a known method. For example, a dry film forming method such as a vapor deposition method and a sputtering method, a wet coating method, a transfer method, and a printing method. It can be suitably formed by a method, an ink jet method, or the like.
The thickness of the electron blocking layer is preferably 1 nm to 200 nm, more preferably 1 nm to 50 nm, and still more preferably 3 nm to 20 nm.

The organic electroluminescent element of the present invention has an organic layer including a light emitting layer between an anode and a cathode, and may have other layers depending on the purpose.
The organic layer has at least the light emitting layer, and has a hole blocking layer, an electron blocking layer, and, if necessary, an electron transport layer, an electron injection layer, a hole injection layer, a hole transport layer, and the like. It may be.

<Hole injection layer, hole transport layer>
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. The hole injection layer and the hole transport layer may have a single layer structure or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The hole injection material or hole transport material used for these layers may be a low molecular compound or a high molecular compound.
The hole injection material or hole transport material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include pyrrole derivatives, carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives. , Polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styryl Examples include amine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, and carbon. These may be used individually by 1 type and may use 2 or more types together.

The hole injection layer and the hole transport layer may contain an electron accepting dopant.
As the electron-accepting dopant, an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.
The inorganic compound is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride; vanadium pentoxide, And metal oxides such as molybdenum trioxide.
The organic compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a compound having a nitro group, a halogen, a cyano group, a trifluoromethyl group or the like as a substituent; a quinone compound, an acid anhydride Compounds, fullerenes, and the like.
These electron-accepting dopants may be used alone or in combination of two or more.
The amount of the electron-accepting dopant used varies depending on the type of material, but is preferably 0.01% by mass to 50% by mass with respect to the hole transport layer material or the hole injection material, and 0.05% by mass to 40% by mass. % Is more preferable, and 0.1% by mass to 30% by mass is still more preferable.

The hole injection layer and the hole transport layer can be formed according to a known method, for example, a vapor deposition method, a dry film forming method such as a sputtering method, a wet coating method, a transfer method, a printing method, an inkjet method, It can form suitably by.
The thickness of the hole injection layer and the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 300 nm, and still more preferably 10 nm to 200 nm.

<Electrode>
The organic electroluminescent element of the present invention includes a pair of electrodes, that is, an anode and a cathode. In view of the nature of the organic electroluminescence device, at least one of the anode and the cathode is preferably transparent. Usually, the anode only needs to have a function as an electrode for supplying holes to the organic compound layer, and the cathode only needs to have a function as an electrode for injecting electrons into the organic compound layer.
There is no restriction | limiting in particular about the shape, a structure, a magnitude | size, etc. as said electrode, According to the use and objective of an organic electroluminescent element, it can select suitably from well-known electrode materials.
As a material which comprises the said electrode, a metal, an alloy, a metal oxide, a conductive compound, or a mixture thereof etc. are mentioned suitably, for example.

-Anode-
Examples of the material constituting the anode include tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Conductive metal oxides; metals such as gold, silver, chromium and nickel; mixtures or laminates of these metals and conductive metal oxides; inorganic conductive materials such as copper iodide and copper sulfide; polyaniline, polythiophene, Examples thereof include organic conductive materials such as polypyrrole, and laminates of these with ITO. Among these, a conductive metal oxide is preferable, and ITO is particularly preferable in terms of productivity, high conductivity, transparency, and the like.

-Cathode-
Examples of the material constituting the cathode include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, Examples thereof include lithium-aluminum alloys, magnesium-silver alloys, rare earth metals such as indium and ytterbium. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.
Among these, alkali metals and alkaline earth metals are preferable from the viewpoint of electron injecting properties, and materials mainly composed of aluminum are particularly preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum). Alloy).

  The method for forming the electrode is not particularly limited and can be performed according to a known method. For example, a wet method such as a printing method or a coating method; a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method; Chemical methods such as CVD and plasma CVD may be used. Among these, it can be formed on the substrate according to a method selected appropriately in consideration of suitability with the material constituting the electrode. For example, when ITO is selected as the anode material, it can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. When a metal or the like is selected as the cathode material, one or more of them can be formed simultaneously or sequentially according to a sputtering method or the like.

  In addition, when patterning is performed when forming the electrode, it may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. It may be performed by sputtering or the like, or may be performed by a lift-off method or a printing method.

<Board>
The organic electroluminescent element of the present invention is preferably provided on a substrate, and may be provided in such a manner that the electrode and the substrate are in direct contact with each other, or may be provided in an intermediate layer. .
The material for the substrate is not particularly limited and may be appropriately selected depending on the intended purpose. For example, inorganic materials such as yttria-stabilized zirconia (YSZ) and glass (such as alkali-free glass and soda lime glass); polyethylene terephthalate And polyesters such as polybutylene phthalate and polyethylene naphthalate; organic materials such as polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, and poly (chlorotrifluoroethylene).

  There is no restriction | limiting in particular about the shape of the said board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. In general, the shape of the substrate is preferably a plate shape. The structure of the substrate may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members. The substrate may be transparent or opaque, and if transparent, it may be colorless and transparent or colored and transparent.

The substrate may be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
Examples of the material of the moisture permeation preventive layer (gas barrier layer) include inorganic substances such as silicon nitride and silicon oxide.
The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.

-Protective layer-
The entire organic electroluminescent element may be protected by a protective layer.
The material contained in the protective layer is not particularly limited as long as it has a function of suppressing the entry of elements that promote element deterioration such as moisture and oxygen into the element. For example, metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni; MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, Fe ₂ Metal oxides such as O ₃ , Y ₂ O ₃ and TiO ₂ ; Metal nitrides such as SiNx and SiNxOy; Metal fluorides such as MgF ₂ , LiF, AlF ₃ and CaF ₂ ; Polyethylene, polypropylene, polymethyl methacrylate, polyimide , Polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, chlorotrifluoroethylene A copolymer of dichlorodifluoroethylene, a copolymer obtained by copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer, a fluorinated copolymer having a cyclic structure in the copolymer main chain, water absorption Examples thereof include a water-absorbing substance having a rate of 1% or more, a moisture-proof substance having a water absorption rate of 0.1% or less, and the like.

  There is no restriction | limiting in particular as a formation method of the said protective layer, According to the objective, it can select suitably, For example, a vacuum evaporation method, sputtering method, reactive sputtering method, MBE (molecular beam epitaxy) method, cluster ion beam method , Ion plating method, plasma polymerization method (high frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method and the like.

-Sealing container-
As for the organic electroluminescent element of this invention, the whole element may be sealed using the sealing container. Furthermore, a moisture absorbent or an inert liquid may be sealed in the space between the sealing container and the organic electroluminescent element.
The moisture absorbent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, chloride Calcium, magnesium chloride, copper chloride, cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like can be given.
The inert liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paraffins, liquid paraffins; fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether; Examples include solvents and silicone oils.

-Resin sealing layer-
The organic electroluminescent device of the present invention is preferably suppressed by sealing the device performance deterioration due to oxygen and moisture from the atmosphere with a resin sealing layer.
The resin material for the resin sealing layer is not particularly limited and can be appropriately selected depending on the purpose. For example, acrylic resin, epoxy resin, fluorine resin, silicone resin, rubber resin, ester resin, Etc. Among these, an epoxy resin is particularly preferable from the viewpoint of moisture prevention function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.

  There is no restriction | limiting in particular as a preparation method of the said resin sealing layer, According to the objective, it can select suitably, For example, the method of apply | coating a resin solution, the method of crimping | bonding or thermocompressing a resin sheet, vapor deposition, sputtering, etc. And a dry polymerization method.

-Sealing adhesive-
The sealing adhesive used in the present invention has a function of preventing intrusion of moisture and oxygen from the end portion.
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, an epoxy adhesive is preferable from the viewpoint of preventing moisture from entering, and a photocurable adhesive or a thermosetting adhesive is particularly preferable.
It is also preferable to add a filler to the sealing adhesive. As the filler, for example _SiO 2, SiO (silicon oxide), SiON (silicon oxynitride), an inorganic material such as SiN (silicon nitride) are preferred. Addition of the filler increases the viscosity of the sealing adhesive, improves processing suitability, and improves moisture resistance.
The sealing adhesive may contain a desiccant. Examples of the desiccant include barium oxide, calcium oxide, and strontium oxide. The addition amount of the desiccant is preferably 0.01% by mass to 20% by mass and more preferably 0.05% by mass to 15% by mass with respect to the sealing adhesive. When the addition amount is less than 0.01% by mass, the effect of adding the desiccant is diminished, and when it exceeds 20% by mass, it is difficult to uniformly disperse the desiccant in the sealing adhesive. Sometimes.
In the present invention, the sealing adhesive containing the desiccant can be applied by applying an arbitrary amount with a dispenser or the like, and the second substrate can be overlaid after application and cured.

  FIG. 1 is a schematic view showing an example of the layer structure of the organic electroluminescent element of the present invention. The organic EL element 11 includes an anode 2 (for example, ITO electrode) formed on the glass substrate 1, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, and holes. It has a layer configuration in which a block layer 7, an electron transport layer 8, an electron injection layer 9, and a cathode 10 (for example, an Al—Li electrode) are stacked in this order. The anode 2 (for example, ITO electrode) and the cathode 10 (for example, Al—Li electrode) are connected to each other via a power source.

-Drive-
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The organic electroluminescent element of the present invention can be applied to an active matrix by a thin film transistor (TFT). As the active layer of the thin film transistor, amorphous silicon, high temperature polysilicon, low temperature polysilicon, microcrystalline silicon, oxide semiconductor, organic semiconductor, carbon nanotube, or the like can be used.
For example, the thin film transistors described in WO2005 / 088826, JP-A-2006-165529, US Patent Application Publication No. 2008 / 0237598A1, and the like can be applied to the organic electroluminescent device of the present invention.

There is no restriction | limiting in particular in the organic electroluminescent element of this invention, Light extraction efficiency can be improved by various well-known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate, ITO layer, organic layer, controlling the thickness of the substrate, ITO layer, organic layer, etc. It is possible to improve the external quantum efficiency.
The light extraction method from the organic electroluminescence device of the present invention may be a top emission method or a bottom emission method.

The organic electroluminescent element of the present invention may have a resonator structure. For example, a multilayer mirror made of a plurality of laminated films having different refractive indexes, a transparent or translucent electrode, a light emitting layer, and a metal electrode are superimposed on a transparent substrate. The light generated in the light emitting layer resonates repeatedly with the multilayer mirror and the metal electrode as a reflection plate.
In another preferred embodiment, a transparent or translucent electrode and a metal electrode each function as a reflecting plate on a transparent substrate, and light generated in the light emitting layer repeats reflection and resonates between them.
In order to form a resonant structure, the optical path length determined from the effective refractive index of the two reflectors and the refractive index and thickness of each layer between the reflectors is adjusted to an optimum value to obtain the desired resonant wavelength. Is done. The calculation formula in the case of the first aspect is described in JP-A-9-180883. The calculation formula in the case of the second aspect is described in Japanese Patent Application Laid-Open No. 2004-127795.

-Use-
The organic electroluminescent element of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. However, the display element, display, backlight, electrophotography, illumination light source, recording light source, exposure light source, reading light source, label It can be suitably used for signboards, interiors, optical communications, and the like.
As a method for making the organic EL display of a full color type, as described in, for example, “Monthly Display”, September 2000, pages 33 to 37, the three primary colors (blue (B), green (G), red light (R)), a three-color light emitting method in which organic EL elements that respectively emit light corresponding to red (R) are arranged on a substrate, and white light emission by an organic electroluminescent element for white light emission is divided into three primary colors through a color filter. A white method, a color conversion method for converting blue light emission by a blue light emitting organic electroluminescent element into red (R) and green (G) through a fluorescent dye layer, and the like are known. Moreover, the planar light source of a desired luminescent color can be obtained by using combining the organic electroluminescent element of the different luminescent color obtained by the said method. For example, a white light-emitting light source combining blue and yellow light-emitting elements, a white light-emitting light source combining blue, green, and red light-emitting elements can be used.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Comparative Example 1)
-Fabrication of organic electroluminescence device-
On a glass substrate having a thickness of 0.5 mm and a square of 2.5 cm, ITO (Indium Tin Oxide) was sputtered to a thickness of 100 nm as an anode. Next, this ITO-attached glass substrate was put into a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. The following layers were deposited on the ITO-attached glass substrate by vacuum deposition. In addition, the vapor deposition rate in the following examples and comparative examples is 0.2 nm / second unless otherwise specified. The deposition rate was measured using a quartz resonator. The following layer thicknesses were measured using a crystal resonator.

First, 4,4′-bis (N- {4- [N- (3-methylphenyl) -N-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD) is formed on the anode (ITO). In addition, a hole injection layer doped with 1% by mass of F4-TCNQ represented by the following structural formula was deposited so as to have a thickness of 30 nm.

Next, an NPD (N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4 represented by the following structural formula as a hole transport layer is formed on the hole injection layer. '-Diamine) was deposited to a thickness of 7 nm.
Next, NPD of the same material as the hole transport layer was deposited as an anode side adjacent layer on the hole transport layer so as to have a thickness of 3 nm.
Next, CBP (4,4′-bis (9-carbazole) -biphenyl) represented by the following structural formula, which is a host material, and a compound represented by the following structural formula, which is a phosphorescent material with respect to the CBP A light emitting layer doped with 10% by mass of (I-15) was deposited so as to have a thickness of 30 nm.

Next, BAlq (Bis- (2-methyl-8-quinolinolato) -4- (phenyl-phenolate) -aluminum (III)) was deposited on the light emitting layer as a cathode side adjacent layer so as to have a thickness of 3 nm. .
Next, BAlq of the same material as the cathode side adjacent layer was deposited on the cathode side adjacent layer so as to have a thickness of 7 nm as an electron transport layer.
Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and an electron injection layer doped with 0.6% by mass of Li to the BCP are formed on the electron transport layer. Was deposited to be 45 nm.
Next, a mask patterned as a cathode (a mask having a light emitting region of 2 mm × 2 mm) was placed on the electron injection layer, and metal aluminum was deposited to a thickness of 100 nm.
The laminate produced as described above was put in a glove box substituted with argon gas, and sealed with a stainless steel sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, an organic electroluminescent element of Comparative Example 1 was produced.

(Comparative Example 2)
-Fabrication of organic electroluminescence device-
Comparative Example 1 except that Compound (I-15) represented by the above structural formula, which is a phosphorescent material, was replaced with Compound (I-6) represented by the following structural formula in Comparative Example 1 as the phosphorescent material. In the same manner as above, an organic electroluminescent device was produced.

(Comparative Example 3)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, as the light-emitting layer, CBP as the host material 1 is 48% by mass, platinum complex F represented by the following structural formula as the host material 2 is 50% by mass, and the above structural formula that is a phosphorescent material An organic electroluminescent device was produced in the same manner as in Comparative Example 1 except that the light emitting layer containing 2% by mass of the compound (I-15) represented by formula (1) was changed.

(Comparative Example 4)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, as the light emitting layer, mCP (N, N′-dicarbazolyl-3,5-benzene) represented by the following structural formula as a host material and the following structural formula as a phosphorescent light emitting material with respect to the mCP An organic electroluminescent element was produced in the same manner as in Comparative Example 1, except that the light emitting layer doped with 10% by mass of the platinum complex X represented by

(Comparative Example 5)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, as a light emitting layer, light emission in which 10% by mass of mCP represented by the above structural formula as a host material and platinum complex X represented by the above structural formula as a phosphorescent light emitting material with respect to the mCP is doped. An organic electroluminescent element was produced in the same manner as in Comparative Example 1 except that the layer was changed to BAlq as the cathode side adjacent layer and the compound (4-15) represented by the following structural formula was changed.

Example 1
-Fabrication of organic electroluminescence device-
An organic electroluminescent element was produced in the same manner as in Comparative Example 1 except that BAlq was changed to the compound (4-15) represented by the above structural formula as the cathode-side adjacent layer in Comparative Example 1.

(Example 2)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, the compound (I-15) represented by the above structural formula, which is a phosphorescent material as the light emitting layer, was replaced with the compound (I-6) represented by the above structural formula, An organic electroluminescent element was produced in the same manner as in Comparative Example 1 except that BAlq was changed to the compound (4-15) represented by the above structural formula.

(Example 3)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, except that BAlq was replaced with the compound (4-15) represented by the above structural formula as the cathode side adjacent layer, and NPD was replaced with the compound A represented by the following structural formula as the anode side adjacent layer. Produced an organic electroluminescent element in the same manner as in Comparative Example 1.

Example 4
-Fabrication of organic electroluminescence device-
In Comparative Example 1, except that BAlq was replaced with the compound (4-15) represented by the above structural formula as the cathode side adjacent layer, and NPD was replaced with the compound B represented by the following structural formula as the anode side adjacent layer. Produced an organic electroluminescent element in the same manner as in Comparative Example 1.

(Example 5)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, the compound (I-15) represented by the above structural formula, which is a phosphorescent material as the light emitting layer, was replaced with the compound (I-6) represented by the above structural formula, In the same manner as in Comparative Example 1, except that BAlq was replaced with the compound (4-15) represented by the structural formula and NPD was replaced with the compound A represented by the structural formula as an anode side adjacent layer, organic An electroluminescent element was produced.

(Example 6)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, as the light emitting layer, CBP as the host material 1 is 48% by mass, platinum complex F represented by the above structural formula as the host material 2 is 50% by mass, and the above structural formula that is a phosphorescent material. As a cathode side adjacent layer, replacing BAlq with the compound (4-15) represented by the above structural formula instead of the light emitting layer containing 2% by mass of the compound (I-15) represented by An organic electroluminescent element was produced in the same manner as in Comparative Example 1 except that NPD was replaced with the compound A represented by the above structural formula.

(Example 7)
-Fabrication of organic electroluminescence device-
In Comparative Example 1, as a light emitting layer, 48% by mass of the compound (H-24) represented by the following structural formula as the host material 1 and 50 platinum complex F represented by the above structural formula as the host material 2 were used. In place of the light emitting layer containing 2% by mass of the compound (I-15) represented by the above structural formula, which is a phosphorescent light emitting material, BAlq is represented by the above structural formula (4) as the cathode side adjacent layer. An organic electroluminescent device was produced in the same manner as in Comparative Example 1 except that NPD was replaced with the compound A represented by the above structural formula instead of −15).

  Next, for the produced Examples 1 to 7 and Comparative Examples 1 to 5, the external quantum efficiency and the driving durability (luminance half time) were measured as follows. The results are shown in Table 1.

<Measurement of external quantum efficiency>
Using a source measure unit type 2400 manufactured by KEITHLEY, each element was supplied with a direct current having a current density of ^2.5 mA / cm ² to emit light. The brightness and emission spectrum were measured using a brightness meter SR-3 manufactured by Topcon Corporation. Based on these measurement results, the external quantum efficiency was calculated by an emission spectrum conversion method.

<Driving durability (Luminance half time)>
The driving durability is constant current driving at an initial luminance of 5,000 cd / m ² , and the luminance half-life of Comparative Example 1, Comparative Example 2, and Comparative Example 4 is set to 100, and the same light emitting layer guest (phosphorescent material) is used. The luminance half time of the element used was shown as a relative value.

From the results shown in Table 1, when Comparative Example 4 and Comparative Example 5 are compared, when the compound (4-15) is used in the cathode side adjacent layer, the use of platinum complex X as the phosphorescent material improves the luminous efficiency, but the drive It turned out that durability will deteriorate.
In Examples 1 to 7, when the compound (I-15) or the compound (I-6) is used as the phosphorescent material and the compound (4-15) is used for the cathode side adjacent layer, the light emission efficiency and the driving durability are increased. Was also found to improve.

  Since the organic electroluminescence device of the present invention can improve high luminous efficiency and driving durability, for example, display device, display, backlight, electrophotography, illumination light source, recording light source, exposure light source, reading light source, sign, signboard, It is suitably used for interior and optical communication.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Electron block layer 6 Light emitting layer 7 Hole block layer 8 Electron transport layer 9 Electron injection layer 10 Cathode 11 Organic electroluminescent element

Claims (5)

Having at least one organic layer including a light emitting layer between an anode and a cathode;
The light emitting layer contains a host material and a phosphorescent light emitting material represented by any one of the following general formulas (1), (2) and (3),
The organic electroluminescent element characterized by the layer adjacent to the cathode side of the said light emitting layer containing the compound represented by following General formula (4).
However, in said general formula (1), (2) and (3), n represents the integer of 1-3. XY represents a bidentate ligand. Ring A represents a ring structure that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom. R ¹¹ represents a substituent, and m1 represents an integer of 0 to 6. When m1 is 2 or more, adjacent R ¹¹ may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹² represents a substituent, and m2 represents an integer of 0 to 4. When m2 is 2 or more, adjacent R ¹² may be bonded to form a ring which may contain any of a nitrogen atom, a sulfur atom and an oxygen atom, and the ring is further substituted with a substituent. May be. R ¹¹ and R ¹² may be bonded to form a ring that may contain any of a nitrogen atom, a sulfur atom, and an oxygen atom, and the ring may be further substituted with a substituent. Good.
However, in said general formula (4), R < ¹ > -R < ⁸ > represents either a hydrogen atom or a substituent, respectively. A represents an aromatic ring, and the aromatic ring may be further substituted with a substituent. m represents an integer of 2 or more. n represents an integer of 1 or more. The organic electroluminescent element of Claim 1 in which the layer adjacent to the anode side of a light emitting layer contains the compound represented by following General formula (5).
In the general formula (5), R ²² represents a hydrogen atom or a substituent. R ²¹ represents a substituent. m3 represents an integer of 0 to 4. The organic electroluminescent element of Claim 1 in which the layer adjacent to the anode side of a light emitting layer contains the compound represented by following General formula (6).
However, in the general formula (6), R ³¹ and R ³² each represent either a hydrogen atom or a substituent, and neither R ³¹ nor R ³² becomes an aryl group. R ³³ and R ³⁴ each represent a substituent. m4 and p each represents an integer of 0 to 4. Q represents a 6-membered ring.   The organic electroluminescent element according to claim 1, wherein the host material is a compound having a carbazole skeleton. The organic electroluminescent element according to any one of claims 1 to 4, wherein the host material is a platinum complex compound represented by the following general formula (7).
However, in said general formula (7), L < ¹ >, L < ² > and L < ³ > represent either a single bond and a coupling group, respectively. R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ each represent a hydrogen atom or a substituent. R ^a and R ^b each represent a substituent, and n and m each represent an integer of 0 to 3.