JPWO2016143508A1 - Organic electroluminescence device and organic electroluminescence device material - Google Patents

Abstract

An object of the present invention is to provide an organic electroluminescence device having high luminous efficiency, low driving voltage and long life, small voltage increase during driving, and excellent stability over time. The organic electroluminescent device of the present invention is an organic electroluminescent device having an organic layer including a light emitting layer between at least a pair of an anode and a cathode, wherein the organic layer is represented by the following general formula (1). It contains the compound which has this. [Chemical 1]

Description

  The present invention relates to an organic electroluminescence element and an organic electroluminescence element material. More specifically, the present invention relates to an organic electroluminescence element that achieves both performance and stability such as luminous efficiency.

An organic electroluminescence element (hereinafter also referred to as “organic EL element”) is an all-film thin film type in which an organic thin film layer (single layer portion or multilayer portion) containing an organic light-emitting substance is formed between an anode and a cathode. It is a solid element.
When a voltage is applied to the organic EL element, electrons are injected from the cathode into the organic thin film layer and holes are injected from the anode, and these are recombined in the light emitting layer (organic light emitting substance-containing layer) to generate excitons. The organic EL element is a light-emitting element using light emission (fluorescence / phosphorescence) from these excitons, and is a technology expected as a next-generation flat display and illumination.

Furthermore, since an organic EL element using phosphorescence emission from an excited triplet, which can realize a luminous efficiency of about 4 times in principle in comparison with an organic EL element using fluorescence emission, has been reported from Princeton University, Starting with the development of materials that exhibit phosphorescence at room temperature, research and development of light-emitting element layer configurations and electrodes are being carried out around the world.
As described above, the phosphorescence emission method is a method having a very high potential. However, in an organic EL device using phosphorescence emission, a method for controlling the position of the emission center is significantly different from that using fluorescence emission. In order to capture the efficiency and lifetime of the device, it is important how recombination can be performed inside the light emitting layer to stabilize light emission.

Therefore, a multilayer stacked device including a hole transport layer located on the anode side of the light emitting layer and an electron transport layer located on the cathode side of the light emitting layer, etc. adjacent to the light emitting layer, or a phosphor layer on the light emitting layer. An element using a mixed layer containing a light-emitting compound and a host compound has been developed.
On the other hand, from the viewpoint of materials, high carrier transportability and thermally and electrically stable materials are demanded. In particular, when using blue phosphorescence, since the blue phosphorescent dopant itself has a high triplet excitation energy level (T ₁ ), development of applicable peripheral materials and precise emission centers are possible. There is a strong demand for control.

One of the conditions of the peripheral material applicable to the element using a blue phosphorescent dopant is high excited triplet energy (T ₁ energy). In particular, when used for a light-emitting layer or a layer adjacent to the light-emitting layer, in general, a material having a T ₁ energy higher than that of the phosphorescent dopant in order to suppress reverse energy transfer from the phosphorescent dopant. is necessary.
For example, carbazole derivatives represented by CBP and mCP are well known as host compounds of phosphorescent dopants. As a compound used with a blue phosphorescent dopant, a compound in which a plurality of carbazole skeletons are bonded to a dibenzofuran skeleton is known. However, these compounds have not reached a sufficiently high T ₁ energy level.

  To date, it is known to use a compound having a structure in which a benzimidazole skeleton is combined with a benzene ring or a pyridine ring as a peripheral material applicable to an element using a blue phosphorescent dopant. (For example, refer to Patent Document 1). In addition, it is known to use a compound having a benzimidazole skeleton and a condensed aromatic heterocycle as a host compound of a phosphorescent dopant (see, for example, Patent Document 2). However, the benzimidazole skeleton has a problem that it easily aggregates and crystallizes because the steric hindrance between the 5-membered ring portion and the group substituted on the benzimidazole skeleton is small.

Further, a compound in which a benzimidazole is substituted on a condensed aromatic heterocycle such as dibenzofuran is known (for example, see Patent Document 3). These compounds inhibit the coplanarity of the benzimidazole moiety and the condensed aromatic heterocycle, so that the interaction necessary for charge transfer can be maintained, while the aggregation between the compounds can be suppressed by the steric hindrance effect, High T ₁ energy levels can be maintained.
However, even when these compounds are used, there is a problem in that the coplanarity of the benzimidazole skeleton and the substituent portion thereof is not sufficiently inhibited, causing aggregation during film formation and crystallization during driving. It was.

JP 2007-258692 A JP 2011-148780 A International Publication No. 2012/004765

  The present invention has been made in view of the above-described problems and situations, and its solution is a high luminous efficiency, a low driving voltage and a long life, a small increase in voltage during driving, and further stability over time. An organic electroluminescence device and an organic electroluminescence device material are provided.

In order to solve the above problems, the present inventor has a high luminous efficiency because the organic layer contains a compound having a structure represented by the following general formula (1) in the process of examining the cause of the problem. Thus, the present inventors have found that an organic electroluminescence device having a low driving voltage and a long lifetime, having a small voltage increase during driving, and having excellent stability over time can be provided.
The above-mentioned problem according to the present invention is solved by the following means.

（一般式（１）において、Ｂはベンズイミダゾールとは異なる縮合芳香族複素環を表す。一般式（１）で表される構造を有する化合物は、炭素数３以上の分岐アルキル基、シクロアルキル基、オルト位に置換基を有する炭素数６以上の芳香族炭化水素環基、オルト位に置換基を有する６員環以上の芳香族複素環基、置換基を有するアミノ基、置換基を有するシリル基、置換基を有するホスホリル基及び置換基を有するチオホスホリル基からなる群から選ばれる基を少なくとも一つ含む置換基Ａ_１を少なくとも一つ以上有し、さらにその他の置換基Ａ_２を有してもよい。）1. An organic electroluminescence device having an organic layer including a light emitting layer between at least a pair of an anode and a cathode,
The organic layer contains a compound having a structure represented by the following general formula (1).

(In General Formula (1), B represents a condensed aromatic heterocycle different from benzimidazole. A compound having a structure represented by General Formula (1) is a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. , An aromatic hydrocarbon ring group having 6 or more carbon atoms having a substituent at the ortho position, an aromatic heterocyclic group having 6 or more member rings having a substituent at the ortho position, an amino group having a substituent, and a silyl having a substituent At least one substituent A ₁ containing at least one group selected from the group consisting of a group, a phosphoryl group having a substituent and a thiophosphoryl group having a substituent, and further having another substituent A ₂ May be.)

2. The HOMO level of B is −5.87 eV or less,
The LUMO level of B is -0.24 eV or less;
The HOMO level of the substituent A ₁ and the other substituent A ₂ is −5.87 eV or less,
_2. The organic electroluminescence device according to item _1, wherein LUMO levels of the substituent A ₁ and the other substituent A ₂ satisfy the following formula (I).
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV

3. The organic according to item 1 or 2, wherein the substituent A ₁ or the other substituent A ₂ is a group consisting of a group selected from the following group of substituents or a combination thereof. Electroluminescence element.
Substituent group:
Alkyl group, cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, non-aromatic heterocyclic group, aromatic heterocyclic group, cyano group, silyl group, phosphoryl group

（一般式（２）において、ＸはＯ又はＳを表す。Ｙ_２１〜Ｙ_２８は、それぞれ独立にＣＨ又はＮを表し、前記置換基Ａ_１又は前記その他の置換基Ａ_２を有してもよい。なお、＊は、一般式（１）で表される構造を有する化合物における結合部位を表す。）4). The organic electroluminescence device according to any one of items 1 to 3, wherein B is a condensed aromatic heterocyclic group represented by the following general formula (2).

(In General Formula (2), X represents O or S. Y ₂₁ to Y ₂₈ each independently represent CH or N, and may have the substituent A ₁ or the other substituent A _2. Note that * represents a binding site in the compound having the structure represented by the general formula (1).

（一般式（３）において、Ｙ_３１〜Ｙ_３３及びＹ_３５〜Ｙ_３７は、それぞれ独立にＯ、Ｓ、Ｎ又はＣＨを表し、Ｎを表す場合は水素原子、非共有電子対又は置換基を有する。Ｙ_３４又はＹ_３８は、ＣＨ又はＮを表す。また、Ｙ_３１〜Ｙ_３８は、それぞれ独立に前記置換基Ａ_１又は前記その他の置換基Ａ_２を有してもよい。なお、＊は、一般式（１）で表される構造を有する化合物における結合部位を表す。）5). The organic electroluminescence device according to any one of items 1 to 3, wherein B is a condensed aromatic heterocyclic group represented by the following general formula (3).

(In General Formula (3), Y _{31 to} Y ₃₃ and Y _{35 to} Y ₃₇ each independently represent O, S, N, or CH. When N is represented, a hydrogen atom, an unshared electron pair, or a substituent is represented. Y ₃₄ or Y ₃₈ represents CH or N. Y _{31 to} Y ₃₈ may each independently have the substituent A ₁ or the other substituent A ₂ . Represents a binding site in a compound having a structure represented by the general formula (1).

（一般式（４）において、Ｙ_４１〜Ｙ_４４は、それぞれ独立にＣＨ又はＮを表す。Ｙ_４５〜Ｙ_４８は、それぞれ独立にＯ、Ｓ、Ｎ又はＣＨを表し、Ｎを表す場合は水素原子、非共有電子対又は置換基を有する。また、Ｙ_４１〜Ｙ_４８は、それぞれ独立に前記置換基Ａ_１又は前記その他の置換基Ａ_２を有してもよい。なお、＊は、一般式（１）で表される構造を有する化合物における結合部位を表す。）6). Said B is condensed aromatic heterocyclic group represented by following General formula (4), The organic electroluminescent element as described in any one of Claim 1 to 3 characterized by the above-mentioned.

In (formula _{(4), Y} 41 _{~Y 44,} the _.Y 45 _{to Y 48} which represents CH or N independently represent each independently O, S, N or CH, hydrogen if it represents a N An atom, an unshared electron pair, or a substituent group, and Y _{41 to} Y ₄₈ may each independently have the substituent group A ₁ or the other substituent group A ₂ . (Represents a binding site in a compound having the structure represented by formula (1).)

（一般式（５）において、Ｙ_５１〜Ｙ_５４は、それぞれ独立にＣＨ又はＮを表す。Ｙ_５５〜Ｙ_５７は、それぞれ独立にＯ、Ｓ、Ｎ又はＣＨを表し、Ｎを表す場合は水素原子、非共有電子対又は置換基を有する。また、Ｙ_５１〜Ｙ_５７は、それぞれ独立に前記置換基Ａ_１又は前記その他の置換基Ａ_２を有してもよい。なお、＊は、一般式（１）で表される構造を有する化合物における結合部位を表す。）7). The organic according to any one of Items 1 to 3, wherein B is a condensed aromatic heterocyclic group different from benzimidazole represented by the following general formula (5): Electroluminescence element.

(In General Formula (5), Y _{51 to} Y ₅₄ each independently represent CH or N. Y ₅₅ to Y ₅₇ each independently represent O, S, N, or CH, and hydrogen represents N. An atom, an unshared electron pair, or a substituent, Y _{51 to} Y ₅₇ may each independently have the substituent A ₁ or the other substituent A _2. Note that * (Represents a binding site in a compound having the structure represented by formula (1).)

（Ｙ_６１〜Ｙ_６６は、それぞれ独立にＯ、Ｓ、Ｎ又はＣＨを表し、Ｎを表す場合は水素原子、非共有電子対又は置換基を有する。Ｙ_６７及びＹ_６８は、それぞれ独立にＣＨ又はＮを表す。また、Ｙ_６１〜Ｙ_６６は、それぞれ独立に前記置換基Ａ_１又は前記その他の置換基Ａ_２を有してもよい。なお、＊は、一般式（１）で表される構造を有する化合物における結合部位を表す。）8). Said B is condensed aromatic heterocycle represented by following General formula (6), The organic electroluminescent element as described in any one of Claim 1 to 3 characterized by the above-mentioned.

_(Y 61 _{to Y 66} each independently represent an O, S, N or CH, the hydrogen atom may represent N, _{.Y 67} and _{Y 68} has an unshared electron pair or substituents, CH independently Or Y _{61 to} Y ₆₆ may each independently have the substituent A ₁ or the other substituent A _2. Note that * is represented by the general formula (1). Represents a binding site in a compound having a structure.

9. The organic electroluminescent element according to any one of items 1 to 8, wherein the substituent A ₁ is a substituent containing a silyl group having a substituent.

  10. The organic light-emitting device according to any one of items 1 to 9, wherein the light-emitting layer contains a compound having a structure represented by the general formula (1).

  11. 11. The organic electroluminescent element according to item 10, wherein the light emitting layer contains an Ir complex as a phosphorescent dopant.

  12 The organic light-emitting device according to item 11, wherein the light-emitting layer contains two or more host compounds including a compound having a structure represented by the general formula (1).

  13. 13. The organic electroluminescence device according to any one of items 1 to 12, wherein the organic layer is manufactured by a wet process.

（一般式（１）において、Ｂはベンズイミダゾールとは異なる縮合芳香族複素環を表す。一般式（１）で表される構造を有する化合物は、炭素数３以上の分岐アルキル基、シクロアルキル基、オルト位に置換基を有する炭素数６以上の芳香族炭化水素環基、オルト位に置換基を有する６員環以上の芳香族複素環基、置換基を有するアミノ基、置換基を有するシリル基、置換基を有するホスホリル基及び置換基を有するチオホスホリル基からなる群から選ばれる基を少なくとも一つ含む置換基Ａ_１を少なくとも一つ以上有し、さらにその他の置換基Ａ_２を有してもよい。）14 An organic electroluminescence device material comprising a compound having a structure represented by the following general formula (1).

(In General Formula (1), B represents a condensed aromatic heterocycle different from benzimidazole. A compound having a structure represented by General Formula (1) is a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. , An aromatic hydrocarbon ring group having 6 or more carbon atoms having a substituent at the ortho position, an aromatic heterocyclic group having 6 or more member rings having a substituent at the ortho position, an amino group having a substituent, and a silyl having a substituent At least one substituent A ₁ containing at least one group selected from the group consisting of a group, a phosphoryl group having a substituent and a thiophosphoryl group having a substituent, and further having another substituent A ₂ May be.)

15. The HOMO level of B is −5.87 eV or less,
The LUMO level of B is -0.24 eV or less;
The HOMO level of the substituent A ₁ and the other substituent A ₂ is −5.87 eV or less,
15. The organic electroluminescence element material according to item 14, wherein LUMO levels of the substituent A ₁ and the other substituent A ₂ satisfy the following formula (I).
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV

  According to the present invention, there are provided an organic electroluminescence element and an organic electroluminescence element material having high luminous efficiency, low driving voltage and long life, small voltage increase during driving, and excellent stability over time. Can do.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
As a device material, the present inventors introduce a site having a greater steric hindrance to a compound in which a condensed aromatic heterocyclic ring is substituted with benzimidazole, and apply it to an organic EL device in combination with a blue phosphorescent dopant. It was found that the interaction between the compounds can be suppressed and the aggregation can be suppressed even in the film state without degrading the performance of the film.
Therefore, by using a compound having the structure represented by the general formula (1) in the organic layer, high emission luminance, low driving voltage, suppression of voltage increase during driving, and longer emission lifetime can be achieved at the same time. As a result, the present invention has been achieved. Furthermore, it has been found that an organic EL device produced using the compound of the present invention can be improved in terms of stability over time.

Schematic diagram showing the relationship between the HOMO level and the LUMO level of each part of the compound according to the present invention. Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of display section A in FIG. Schematic diagram of pixels Schematic diagram of passive matrix type full color display device Schematic of lighting device Schematic diagram of lighting device Schematic configuration diagram of organic EL full-color display device Schematic configuration diagram of organic EL full-color display device Schematic configuration diagram of organic EL full-color display device Schematic configuration diagram of organic EL full-color display device Schematic configuration diagram of organic EL full-color display device

  The organic electroluminescent element of the present invention is an organic electroluminescent element having an organic layer including a light emitting layer between at least a pair of an anode and a cathode, wherein the organic layer is represented by the general formula (1). It contains the compound which has this. This feature is a technical feature common to the claimed invention.

As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the HOMO level of B (hereinafter also referred to as HOMO energy level) is −5.87 eV or less, and the LUMO level of B (Hereinafter also referred to as LUMO energy level) is −0.24 eV or less, and the HOMO levels of the substituent A ₁ and the other substituent A ₂ are −5.87 eV or less, and the substitution It is preferable that the LUMO levels of the group A ₁ and the other substituent A ₂ satisfy the formula (I). This is because a high T ₁ energy level can be maintained even when the film is formed.

As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the substituent A ₁ or the other substituent A ₂ is a substituent selected from a group selected from the substituent group or a combination thereof. It is preferable.

  Moreover, as an embodiment of the present invention, it is preferable that B is a condensed aromatic heterocyclic group represented by the general formula (2) from the viewpoint of manifesting the effects of the present invention.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the B is preferably a condensed aromatic heterocyclic group represented by the following general formula (3).

  Moreover, as an embodiment of the present invention, it is preferable that B is a condensed aromatic heterocyclic group represented by the following general formula (4) from the viewpoint of manifesting the effects of the present invention.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the B is preferably a condensed aromatic heterocyclic group different from benzimidazole represented by the following general formula (5). .

  Moreover, as an embodiment of the present invention, it is preferable that B is a condensed aromatic heterocycle represented by the following general formula (6) from the viewpoint of manifesting the effects of the present invention.

As an embodiment of the present invention, it is preferable that the substituent A ₁ is a substituent including a silyl group having a substituent, from the viewpoint of manifesting the effect of the present invention. This is because it becomes possible to suppress the aggregation of the compound.

  As an embodiment of the present invention, it is preferable that the light emitting layer contains a compound having a structure represented by the general formula (1) from the viewpoint of manifesting the effects of the present invention.

  As an embodiment of the present invention, it is preferable that the light emitting layer contains an Ir complex as a phosphorescent dopant from the viewpoint of manifesting the effects of the present invention.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the light emitting layer contains two or more host compounds including a compound having a structure represented by the general formula (1). Is preferred.

  Moreover, as an embodiment of the present invention, it is preferable that the organic layer is produced by a wet process from the viewpoint of manifesting the effect of the present invention.

  Moreover, the organic electroluminescent element material of this invention contains the compound which has a structure represented by the said General formula (1), It is characterized by the above-mentioned.

As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the HOMO level of B is −5.87 eV or less, and the LUMO level of B is −0.24 eV or less. The HOMO level of the substituent A ₁ and the other substituent A ₂ is −5.87 eV or less, and the LUMO level of the substituent A ₁ and the other substituent A ₂ is represented by the formula ( It is preferable to satisfy I).

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "to" is used in the meaning which includes the numerical value described before and behind as a lower limit and an upper limit.

<< Constituent layer of organic electroluminescence element >>
As typical element structures in the organic EL element of the present invention, the following structures can be exemplified, but the invention is not limited thereto.
(1) Anode / light emitting layer / cathode (2) Anode / light emitting layer / electron transport layer / cathode (3) Anode / hole transport layer / light emitting layer / cathode (4) Anode / hole transport layer / light emitting layer / electron Transport layer / cathode (5) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (6) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode ( 7) Anode / hole injection layer / hole transport layer / (electron blocking layer /) luminescent layer / (hole blocking layer /) electron transport layer / electron injection layer / cathode Among the above, the configuration of (7) is preferable. Although used, it is not limited to this.

The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.
If necessary, a hole blocking layer (also referred to as a hole blocking layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode. 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 therebetween.

The electron transport layer used in the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Moreover, you may be comprised by multiple layers.
The hole transport layer used in the present invention is a layer having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Moreover, you may be comprised by multiple layers.
In the above-described typical element configuration, a layer excluding the anode and the cathode is referred to as an “organic layer”.

(Tandem structure)
The organic EL element of the present invention may be a so-called tandem element in which a plurality of light emitting units including at least one light emitting layer are stacked.
As typical element configurations of the tandem structure, for example, the following configurations can be given.
Anode / first light emitting unit / second light emitting unit / third light emitting unit / cathode Anode / first light emitting unit / intermediate layer / second light emitting unit / intermediate layer / third light emitting unit / cathode Here, the first light emitting unit The second light emitting unit and the third light emitting unit may all be the same or different. Further, the two light emitting units may be the same, and the remaining one may be different.

The third light emitting unit may not be provided, and on the other hand, 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 laminated directly or 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, an intermediate layer. Known materials and structures can be used as long as they are also called insulating layers and have a function of supplying electrons to the anode-side adjacent layer and holes to the cathode-side adjacent layer.

Examples of materials used for the intermediate layer include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, and CuAlO _2. , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO ₂ , Al, etc., conductive inorganic compound layers, Au / Bi ₂ O _3, etc., two-layer films, SnO ₂ / Ag / SnO ₂ , ZnO / Ag / ZnO, Bi ₂ O ₃ / Au / Bi ₂ O ₃ , TiO ₂ / TiN / TiO ₂ , TiO ₂ / ZrN / TiO _{2 and} other multilayer films, C _{60 and} other fullerenes, conductive organic layers such as oligothiophene Conductive organic compound layers such as metal phthalocyanines, metal-free phthalocyanines, metal porphyrins, metal-free porphyrins, The present invention is not limited to these.

Examples of a preferable configuration in the light emitting unit include those obtained by removing the anode and the cathode from the configurations (1) to (7) described in the above representative element configurations, but the present invention is not limited thereto. Not.
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. Specification, US Pat. No. 6,337,492, International Publication No. 2005/009087, JP-A 2006-228712, JP-A 2006-24791, JP-A 2006-49393, JP-A 2006-49394 JP-A-2006-49396, JP-A-2011-96679, JP-A-2005-340187, JP-A-4711424, JP-A-34966681, JP-A-3848564, JP-A-4421169, JP 2010-192719, JP 009-076929, JP 2008-078414 A, JP 2007-059848 A, JP 2003-272860 A, JP 2003-045676 A, International Publication No. 2005/094130, etc. Although a structure, a constituent material, etc. are mentioned, this invention is not limited to these.
Next, the compound contained in the organic layer will be described, and each layer will be described.

<< Compound Represented by Formula (1) >>
The organic layer according to the present invention contains a compound having a structure represented by the following general formula (1). Moreover, it is preferable that the compound which has a structure represented by following General formula (1) is contained in organic electroluminescent element material.

In the general formula (1), B represents a condensed aromatic heterocyclic ring different from benzimidazole. The compound having the structure represented by the general formula (1) includes a branched alkyl group having 3 or more carbon atoms, a cycloalkyl group, an aromatic hydrocarbon ring group having 6 or more carbon atoms having a substituent at the ortho position, and an ortho position. A group selected from the group consisting of a 6-membered or more aromatic heterocyclic group having a substituent, an amino group having a substituent, a silyl group having a substituent, a phosphoryl group having a substituent, and a thiophosphoryl group having a substituent It may have at least one substituent A ₁ containing at least one and may further have other substituents A ₂ .
Incidentally, the above 6-membered ring aromatic heterocyclic group, the amino group, the silyl group, a substituent wherein the phosphoryl group and the thiophosphoryl group has is be used as the other substituents A ₂ shown below It can be selected from possible substituents. Further, the branched alkyl group and the cycloalkyl group may have a substituent can be used as other substituents A ₂ shown below.
Further, the substituent A ₁ may be further substituted with another substituent A ₂ .
In addition, the horizontal line which penetrates structural formula from B represents the bond substituted at any position among the structures represented by the general formula (1). The same applies to the following general formulas (2) to (6).

The other substituent A ₂ is an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group). , Pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, propargyl group, etc.), aromatic hydrocarbon group (aryl) For example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc. ), Non-aromatic heterocyclic group (eg, epoxy ring, aziridine ring) , Thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam Ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring Thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane ring, etc.), aromatic heterocyclic group (pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimilyl group) Dazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzooxazolyl group , Thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group ( One of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced with a nitrogen atom), a quinoxalinyl group, a pyridazinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, etc.), a halogen atom (for example, a chlorine atom, a bromine group) Atoms, iodine atoms, fluorine atoms, etc.), Al Xyl group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryl An oxy group (for example, phenoxy group, naphthyloxy group, etc.), an alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), a cycloalkylthio group (for example, cyclopentylthio group) Group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, Octyloxycarbonyl group, dodecyloxycarbonyl group etc.), aryloxycarbonyl group (eg phenyloxycarbonyl group, naphthyloxycarbonyl group etc.), sulfamoyl group (eg aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, Butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), ureido group (for example, methylureido) Group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido Group, 2-pyridylaminoureido group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenyl) Carbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide Groups (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonyl group) Amino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group) Propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.) Sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethyl Ruhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group or arylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, diarylamino group (for example, diphenylamino group, dinaphthylamino group, phenylnaphthylamino group, etc.), naphthyl Amino group, 2-pyridylamino group, etc.), nitro group, cyano group, hydroxy group, alkylsilyl group or arylsilyl group (for example, trimethylsilyl group, triethylsilyl group, (t) butyldimethylsilyl group, triisopropylsilyl group, ( t) butyldiphenylsilyl group, triphenylsilyl group, trinaphthylsilyl group, 2-pyridylsilyl group, etc.), alkylphosphino group or arylphosphino group (dimethylphosphino group, diethylphosphino group, dicyclohexylphosphino group, Methylphenylphosphino group, diphenylphosphino group, dinaphthylphosphino group, di (2-pyridyl) phosphosphino group), alkylphosphoryl group or arylphosphoryl group (dimethylphosphoryl group, diethylphosphoryl group, dicyclohexylphosphoryl group) Methylphenylphosphoryl group, diphenylphosphoryl group, dinaphthylphosphoryl group, di (2-pyridyl) phosphoryl group), alkylthiophosphoryl group or arylthiophosphoryl group (dimethylthiophosphoryl group, diethylthiophosphoryl group, dicyclohexylthiophosphoryl group, methylphenyl) thiophosphoryl group, diphenyl thio phosphoryl group, dinaphthyl Lucio phosphoryl group, di (2-pyridyl) thiophosphoryl group) and the like, if a plurality of other substituents a _2, selecting the substituents each independently can do. These groups may be further substituted with the above substituents, or they may be condensed with each other to form a ring.

In the present invention, the compound represented by the general formula (1) has a structure in which B, which is a condensed aromatic heterocyclic ring, is substituted on the benzimidazole skeleton, so that it has the same planarity due to steric hindrance due to the benzimidazole skeleton and the condensed ring. Is inhibited and aggregation of compounds can be suppressed. Moreover, since B is a condensed aromatic heterocyclic ring, a high T ₁ energy level can be maintained. Furthermore, since the substituent A ₁ is a group containing a substituent having high steric hindrance, aggregation at the time of film formation can also be suppressed. In addition, since solubility can be improved, the suitability for production by a wet process can be improved.

Further, the HOMO level of B is −5.87 eV or less, the LUMO level of B is −0.24 eV or less, and the HOMO levels of the substituent A ₁ and the other substituent A ₂ It is preferable that the position is −5.87 eV or less, and the LUMO levels of the substituent A ₁ and the other substituent A ₂ satisfy the following formula (I).
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV
Here, the HOMO level and LUMO level of the substituent refer to the HOMO level and LUMO level of the “substituent-derived compound”. “Substituent-derived compound” refers to a compound formed by bonding a hydrogen atom to the substituent. For example, in the case of B, which is a group according to the present invention, BH is a substituent-derived compound. In the case of the substituent A ₁ and the other substituent A ₂ , A ₁ -H and A ₂ -H are substituent-derived compounds, respectively.

The reason why the HOMO level and the LUMO level of the B, the substituent A ₁ and the other substituent A ₂ are defined will be described.
Even when the substituent A ₁ having a large steric hindrance is used, the benzimidazole skeleton and the portion of the substituent may have some coplanarity when the film is formed. In that case, in order to maintain a high T ₁ energy level, the HOMO site and the LUMO site are preferably localized in different sites.
That is, in the benzimidazole skeleton in the general formula (1), the HOMO site of the compound having the structure represented by the general formula (1) is localized, and the LUMO site is localized in B in the general formula (1). It is preferable to be present. Further, the substituent A ₁ and the other substituent A ₂ do not affect the HOMO site and the LUMO site in order to maintain the high T ₁ energy level of the compound having the structure represented by the general formula (1). A level is preferable. That is, by setting the HOMO level and the LUMO level of B, the substituent A ₁ , and the other substituent A _{2 in} the general formula (1) within a specified range, a high T ₁ energy can be obtained even when a film is formed. It becomes possible to hold the level.

The values of the HOMO level and the LUMO level of the compound represented by the general formula (1) are Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, software for molecular orbital calculation manufactured by Gaussian, USA). , Et al, Gaussian, Inc., Pittsburgh PA, 2002.) and calculated by performing structural optimization using B3LYP / 6-31G * as a keyword (in units of eV) (Converted value). This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.
In the present invention, the HOMO level and LUMO level of each group were determined by substituting the benzimidazole ring or the group represented by B in the general formula (1) with a hydrogen atom. For example, in the case of the imidazole ring of the general formula (1), the following values are calculated by calculating the HOMO level and LUMO level of the substituent-derived compound in which B is replaced with a hydrogen atom.

Moreover, when calculating | requiring the HOMO level and LUMO level of the condensed aromatic ring represented by B, a benzimidazole ring is substituted by a hydrogen atom and it calculates as BH. Similarly, the substituent A _{1 is} also calculated as A ₁ -H, and the other substituent A ₂ is also calculated as A ₂ -H. Based on this value, the relationship between the HOMO level and the LUMO level of the benzimidazole skeleton, B, and the substituent A ₁ or other substituent A ₂ in the present invention is shown in FIG.
In FIG. 1, the HOMO level and the LUMO level of the benzimidazole skeleton are represented as “I-HOMO” and “I-LUMO”, respectively. Further, the HOMO level and the LUMO level of the condensed aromatic ring represented by B are represented as “B-HOMO” and “B-LUMO”, respectively. Furthermore, for the substituent _{A 1} or other substituents _{A 2,} as the HOMO level and LUMO level of the substituent _{A 1} or other substituents _{A 2,} respectively, _{"A 1,} A 2 -HOMO" and "A ₁ , A ₂ -LUMO ”.

In order to localize the LUMO site in B, the HOMO level and LUMO level of B are preferably smaller than the calculated HOMO level and LUMO level of the benzimidazole skeleton. However, even if the HOMO level and the LUMO level are the same as those of the benzimidazole skeleton, the function of the present invention is sufficiently achieved if the HOMO level is localized in the benzimidazole and the LUMO level is localized in the B.
That is, in consideration of a slight difference caused by a change in the electronic state due to a substituent, which occurs when an actual molecule is assembled, B has a HOMO level of −5.87 eV or less and a LUMO level of −0.24 eV. It is preferable that

On the other hand, since the substituent A ₁ and the other substituent A ₂ do not affect the HOMO site and the LUMO site, the LUMO level is larger than the LUMO site B, and the HOMO level is the HOMO site. It is preferably smaller than the benzimidazole skeleton. However, even if the LUMO level is about the same as that of B, the LUMO level can sufficiently perform the function of the present invention if the LUMO is localized in the condensed aromatic heterocycle represented by B. The same applies to the HOMO level. In addition, if HOMO is localized in the benzimidazole skeleton, the function required in the present invention is sufficiently achieved.
That is, in consideration of a slight difference caused by a change in the electronic state due to a substituent, which occurs when an actual molecule is assembled, the substituent A ₁ and the other substituent A ₂ have a HOMO level of −5.87 eV or less. The LUMO level preferably satisfies the following formula.
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV

By thus separating the HOMO site and LUMO site, not only hold the T ₁ energy level at the membrane, when the positive charge state and the negative charge state coexist, energy loss at the same site of the host molecule It can prevent life from occurring. As a result, the expansion and contraction and movement of the bond occurring at the time of deactivation can be suppressed, the stability of the molecule is improved, and the lifetime is improved.

Further, the substituent A ₁ or the other substituents A ₂ is preferably a substituent formed from a base or a combination thereof selected from the following substituent group.
Substituent group:
Alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, non-aromatic heterocyclic group, an aromatic heterocyclic group, a cyano group, a silyl group, also phosphoryl group, substituents A ₁ is of Of the substituents, a substituent containing a silyl group having a substituent is particularly preferable.

  Moreover, it is preferable that B is a condensed aromatic heterocyclic group represented by the following general formula (2).

In the general formula (2), X represents O or S. Y _{21 to} Y ₂₈ each independently represent CH or N, and may have the substituent A ₁ or the other substituent A ₂ . In the following, * represents a binding site in the compound having the structure represented by the general formula (1).

  Moreover, it is preferable that B is a condensed aromatic heterocyclic group represented by the following general formula (3).

In General Formula (3), Y _{31 to} Y ₃₃ and Y _{35 to} Y ₃₇ each independently represent O, S, N, or CH, and when N is represented, each has a hydrogen atom, an unshared electron pair, or a substituent. . Y ₃₄ or Y ₃₈ represents CH or N. Y _{31 to} Y ₃₈ may each independently have the substituent A ₁ or the other substituent A ₂ .

  Moreover, it is preferable that B is a condensed aromatic heterocyclic group represented by the following general formula (4).

In the general formula _{(4), Y} 41 ~Y ₄₄ represents CH or N independently. Y _{45 to} Y ₄₈ each independently represents O, S, N, or CH, and in the case of representing N, each has a hydrogen atom, an unshared electron pair, or a substituent. Y _{41 to} Y ₄₈ may each independently have the substituent A ₁ or the other substituent A ₂ .

  Moreover, it is preferable that said B is a condensed aromatic heterocyclic group different from benzimidazole represented by the following general formula (5).

In the general formula _{(5), Y} 51 ~Y ₅₄ represents CH or N independently. Y _{55 to} Y ₅₇ each independently represent O, S, N, or CH, and in the case of representing N, each has a hydrogen atom, an unshared electron pair, or a substituent. Y _{51 to} Y ₅₇ may each independently have the substituent A ₁ or the other substituent A ₂ .

  The B is preferably a condensed aromatic heterocycle represented by the following general formula (6).

Y _{61 to} Y ₆₆ each independently represent O, S, N, or CH, and when N is represented, each has a hydrogen atom, a lone pair, or a substituent. Y ₆₇ and Y ₆₈ each independently represent CH or N. Y _{61 to} Y ₆₆ may each independently have the substituent A ₁ or the other substituent A ₂ .

  Hereinafter, although the specific example of a compound represented by General formula (1) based on this invention is shown, this invention is not limited to these.

≪Synthesis example≫
Although the synthesis example of the compound represented by General formula (1) is demonstrated below, this invention is not limited to this. Among the specific examples, a method for synthesizing Exemplified Compound H2-6 and Exemplified Compound H2-7 will be described below as an example.

<Synthesis of Exemplified Compound H2-6>
Illustrative compound H2-6 can be synthesized according to the following scheme.

  Under a nitrogen stream, 5.0 g (13.4 mmol) of Intermediate 1, 4.72 g (29.5 mmol) of Intermediate 2, 10.2 g (48.2 mmol) of potassium phosphate, copper oxide ( I) 0.58 g (4.02 mmol) and 1.48 g (8.04 mmol) of dipivaloylmethane were added, 135 mL of dimethyl sulfoxide (DMSO) was added, and the mixture was heated at 160 ° C. for 17 hours. The reaction mixture was allowed to cool to room temperature, water was added, and the mixture was extracted with ethyl acetate and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography to obtain 1.9 g (yield 29%) of Exemplary Compound H2-6. The structure was confirmed by nuclear magnetic resonance spectrum. In addition, what further sublimated and refined this compound was used for preparation of the organic EL element mentioned later.

<Synthesis of Exemplified Compound H2-7>
Illustrative compound H2-7 can be synthesized according to the following scheme.

(Synthesis of Intermediate 3)
Under a nitrogen stream, 10.0 g (26.8 mmol) of intermediate 1, 4.51 g (28.1 mmol) of intermediate 2, 20.5 g (96.5 mmol) of potassium phosphate, copper oxide ( I) 1.15 g (8.04 mmol) and 2.96 g (16.1 mmol) of dipivaloylmethane were added, 270 mL of dimethylsulfoxide was added, and the mixture was heated at 160 ° C. for 3 hours. The reaction mixture was allowed to cool to room temperature, water was added, and the mixture was extracted with ethyl acetate and concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography to obtain 3.95 g of Intermediate 3 (yield 30%).

(Synthesis of Exemplified Compound H2-7)
Under a nitrogen stream, 54 ml of a tetrahydrofuran solution of 2.65 g of Intermediate 3 (5.46 mmol) was cooled to −78 ° C., and then 5 ml of a hexane solution (1.6 mol / L) of n-butyllithium was slowly added dropwise. To this reaction solution, 2.9 g (9.9 mmol) of triphenylsilyl chloride was added. The reaction solution was returned to room temperature and stirred for 4 hours. Water was added, extracted with ethyl acetate, and concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography to obtain 3.0 g (yield 96%) of exemplary compound H2-7. The structure was confirmed by nuclear magnetic resonance spectrum. In addition, what further sublimated and refined this compound was used for preparation of the organic EL element mentioned later.

<Light emitting layer>
The organic layer according to the present invention has a light emitting layer. The light emitting layer according to the present invention is a layer that provides a field in which electrons and holes injected from an electrode or an adjacent layer are recombined to emit light via excitons, and the light emitting portion is a layer of the light emitting layer. Even within, it may be 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 defined in the present invention.
The compound which has a structure represented by General formula (1) based on this invention should just be contained in the organic layer, and it is preferable to contain in a light emitting layer.

The total thickness of the light emitting layer is not particularly limited, but it is possible to prevent the homogeneity of the layer to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color against the driving current. Therefore, it is preferable to adjust to the range of 2 nm to 5 μm, more preferably to the range of 2 to 500 nm, and further preferably to the range of 5 to 200 nm.
In the present invention, the thickness of each light emitting layer is preferably adjusted to a range of 2 nm to 1 μm, more preferably adjusted to a range of 2 to 200 nm, and further preferably adjusted to a range of 3 to 150 nm. The
The light emitting layer according to the present invention 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).

<Host compound>
In the present invention, a compound having a structure represented by the general formula (1) is preferably used as a host compound. Moreover, it is also preferable that the said light emitting layer contains 2 or more types of host compounds containing the compound which has a structure represented by the said General formula (1).
The host compound used in the present invention is a compound mainly responsible for charge injection and transport in the light emitting layer, and its own light emission is not substantially observed in the organic EL device.
Preferably, it is a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1 at room temperature (25 ° C.), more preferably a compound having a phosphorescence quantum yield of less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.
Moreover, it is preferable that the excited state energy of a host compound is higher than the excited state energy of the light emission dopant contained in the same layer.
A host compound may be used independently or may be used in combination of multiple types. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient.

There is no restriction | limiting in particular as a host compound which can be used by this invention, The compound conventionally used with an organic EL element can be used. It may be a low molecular compound or a high molecular 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, while having a hole transporting ability or an electron transporting ability, the emission of light is prevented from being increased in wavelength, and the organic EL element is stable against heat generation during driving at a high temperature or during element driving. From the viewpoint of operation, it is preferable to have a high glass transition temperature (Tg). Tg is preferably 90 ° C. or higher, more preferably 120 ° C. or higher.
Here, the glass transition temperature (Tg) is a value obtained by a method based on JIS K 7121-2012 using DSC (Differential Scanning Colorimetry).

Specific examples of known host compounds used in the organic EL device of the present invention include compounds described in the following documents, but the present invention is not limited thereto.
JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, US 2003/0175553, US 2006/0280965, US Publication No. 2005/0112407, United States Patent Publication No. 2009/0017330, United States Patent Publication No. 2009/0030202, United States Patent Publication No. 2005/0238919, International Publication No. 2001/039234. International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/063796, 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. 2008-200347. No. 074939, JP-A-2007-254297, European Patent No. 2034538, and the like.

<Luminescent dopant>
As the luminescent dopant used in the present invention, a fluorescent luminescent dopant (also referred to as a fluorescent dopant or a fluorescent compound) and a phosphorescent dopant (also referred to as a phosphorescent dopant or a phosphorescent compound) are preferably used. In the present invention, it is preferable that at least one light emitting layer contains a phosphorescent dopant.
The concentration of the luminescent dopant in the luminescent layer can be arbitrarily determined based on the specific dopant used and the requirements of the device, and is contained at a uniform concentration in the thickness direction of the luminescent layer. It may also have an arbitrary concentration distribution.

Moreover, the light emission dopant used for this invention may be used in combination of multiple types, and may combine and use the combination of the dopants from which a structure differs, and the fluorescence emission dopant and a phosphorescence emission dopant. Thereby, arbitrary luminescent colors can be obtained.
The light emission color of the organic EL device of the present invention and the compound used in the present invention is shown in FIG. 5.16 on page 108 of “New Color Science Handbook” (Edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the luminance meter CS-1000 (manufactured by Konica Minolta Co., Ltd.) is applied to the CIE chromaticity coordinates.
In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting dopants having different emission colors and emits white light.
There are no particular limitations on the combination of the light-emitting dopants that exhibit white, and examples include blue and orange, and a combination of blue, green, and red.
The white color in the organic EL device of the present invention is not particularly limited, and may be white near orange or white near blue, but when the 2 ° viewing angle front luminance is measured by the method described above. The chromaticity in the CIE 1931 color system at 1000 cd / m ² is preferably in the region of x = 0.39 ± 0.09 and y = 0.38 ± 0.08.

(Phosphorescent dopant)
The phosphorescent dopant according to the present invention (hereinafter also referred to as “phosphorescent dopant”) is a compound in which light emission from an excited triplet is observed, and specifically, phosphorous dopant at room temperature (25 ° C.). It is a compound that emits light, and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., but a preferable phosphorescence quantum yield is 0.1 or more.
The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. It is an energy transfer type to obtain light emission from a phosphorescent dopant. The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, and carrier recombination occurs on the phosphorescent dopant to emit light from the phosphorescent dopant. In any case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.
As a phosphorescence dopant which can be used in this invention, it can select from the well-known thing used for the light emitting layer of an organic EL element suitably, and can use it.

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. Lett. 78, 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. 2006/020202194. U.S. Patent Publication No. 2007/0087321, U.S. Patent Publication No. 2005/0244673, Inorg. Chem. , 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. , 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. , 34, 592 (2005), Chem. Commun. , 2906 (2005), Inorg. 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, and US Pat. No. 7,332,232. US Patent Publication No. 2009/0108737, US Patent Publication No. 2009/0039776, US Patent No. 6921915, US Patent No. 6,687,266, 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 Pat. No. 7,250,226, US Pat. No. 7,396,598, US Patent Publication No. 2006 0263635 Pat, U.S. Patent Publication No. 2003/0138657, U.S. Patent Publication No. 2003/0152802, U.S. Patent No. 7090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. , 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics, 23, 3745 (2004), Appl. Phys. Lett. , 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. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, U.S. Publication No. 2006/0251923, U.S. Publication No. 2005/0260441, U.S. Pat. No. 7,393,599. , U.S. Pat. No. 7,534,505, U.S. Pat. No. 7,445,855, U.S. Patent Publication No. 2007/0190359, U.S. Patent Publication No. 2008/0297033, U.S. Pat. No. 7,338,722, U.S. Pat. Release 200 No. 034984, U.S. Pat. No. 7,279,704, U.S. Patent Publication No. 2006/098120, U.S. Patent Publication No. 2006/103874, WO 2005/076380, WO 2010/032663. No., 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, WO2012 / 020327, WO2011 / 051404, WO2011 / 004639, WO2011 / 073149, US2012 / 2285853, US2012 / 1221212 Specification, JP 2012-069737 A, JP 2012-195554 A, JP 2009-114086 A, JP 2003-81988 A, JP 2002-302671 A, JP 2002-363552 A. Such as a gazette.
Among these, a preferable phosphorescent dopant includes an organometallic complex having Ir as a central metal. More preferably, a complex containing at least one coordination mode among metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond is preferable.

(Fluorescent dopant)
The fluorescent dopant used in the present invention (hereinafter, also referred to as “fluorescent dopant”) is a compound that can emit light from an excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.
Examples of the fluorescent dopant used in the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluoranthene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron complexes, coumarins. Derivatives, pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, rare earth complex compounds, and the like.

In recent years, light emitting dopants utilizing delayed fluorescence have been developed, and these may be used.
Specific examples of the luminescent dopant using delayed fluorescence include, for example, compounds described in International Publication No. 2011/156793, Japanese Patent Application Laid-Open No. 2011-213643, Japanese Patent Application Laid-Open No. 2010-93181, and the like. Is not limited to these.

《Electron transport layer》
In the present invention, the electron transport layer is 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.
Although there is no restriction | limiting in particular about the total layer thickness of the electron carrying layer used for this invention, Usually, it is the range of 2 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.
Further, in the organic EL element, when the light generated in the light emitting layer is extracted from the electrode, the light extracted directly from the light emitting layer interferes with the light extracted after being reflected by the electrode from which the light is extracted and the electrode located at the counter electrode. It is known to wake up. When light is reflected by the cathode, this interference effect can be efficiently utilized by appropriately adjusting the thickness of the electron transport layer between several nanometers and several micrometers.

On the other hand, when the layer thickness of the electron transport layer is increased, the voltage is likely to rise. Therefore, particularly when the layer thickness is large, the electron mobility of the electron transport layer is 1 × 10 ⁻⁵ cm ² / Vs or more. Is preferred.
The material used for the electron transport layer (hereinafter referred to as an electron transport material) may have any of an electron injecting property, a transporting property, and a hole blocking property. Any one can be selected and used.

  For example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more carbon atoms constituting the carbazole ring are substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, pyridazine derivatives, Triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, azatriphenylene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, etc.), dibenzofuran derivatives, And dibenzothiophene derivatives, silole derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.).

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

In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.
Further, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In the electron transport layer used in the present invention, the electron transport layer may be doped with a doping material as a guest material to form an electron transport layer having a high n property (electron rich). Examples of the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004) and the like.

Specific examples of known preferable electron transport materials used in the organic EL device of the present invention include compounds described in the following documents, but the present invention is not limited thereto.
US Pat. No. 6,528,187, US Pat. No. 7,230,107, US Patent Publication No. 2005/0025993, US Patent Publication No. 2004/0036077, US Patent Publication No. 2009/0115316, US Patent Publication No. 2009/0101870, United States Patent Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/132805, Appl. Phys. Lett. , 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79,156 (2001), U.S. Patent No. 7964293, U.S. Patent Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387. , International Publication No. 2006/067931, International Publication No. 2007/085652, International Publication No. 2008/114690, International Publication No. 2009/066942, International Publication No. 2009/066779, International Publication No. 2009/054253, International Publication No. Publication No. 2011/086935, International Publication No. 2010/150593, International Publication No. 2010/047707, EP23111826, JP2010-251675A, JP2009-209133A, JP2009-124114A, Special JP 2008-277810 A, JP 2006-156445 A, JP 2005-340122 A, JP 2003-45662 A, JP 2003-31367 A, JP 2003-282270 A, International Publication 2012. / 115034.

More preferable electron transport materials in the present invention include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.
Specific preferred examples of the compound used for the electron transport layer of the organic EL device of the present invention are shown below, but the present invention is not limited thereto.
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 transport 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. By blocking the holes, the probability of recombination of electrons and holes can be improved.
Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer used for this invention as needed.
The hole blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the cathode side of the light emitting layer.
The layer thickness of the hole blocking layer used in the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.
As the material used for the hole blocking layer, the material used for the above-described electron transport layer is preferably used, and the material used as the above-described host compound is also preferably used for the hole blocking layer.

《Electron injection layer》
The electron injection layer (also referred to as “cathode buffer layer”) used in the present invention is a layer provided between the cathode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. 2 and Chapter 2 “Electrode Materials” (pages 123 to 166) of the 2nd edition of “The Forefront of Industrialization” (issued by NTT Corporation on November 30, 1998).
In the present invention, the electron injection layer may be provided as necessary, and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.
The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Moreover, the nonuniform film | membrane in which a constituent material exists intermittently may be sufficient.

The details of the electron injection layer are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. , Metals typified by strontium and aluminum, alkali metal compounds typified by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkaline earth metal compounds typified by magnesium fluoride, calcium fluoride, etc., oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by lithium 8-hydroxyquinolate (Liq), and the like. Further, the above-described electron transport material can also be used.
Moreover, the material used for said electron injection layer may be used independently, and may be used in combination of multiple types.

《Hole transport layer》
In the present invention, the hole transport layer is made of a material having a function of transporting holes and may have a function of transmitting holes injected from the anode to the light emitting layer.
Although there is no restriction | limiting in particular about the total layer thickness of the positive hole transport layer used for this invention, Usually, it is the range of 5 nm-5 micrometers, More preferably, it is 2-500 nm, More preferably, it is 5-200 nm.
The material used for the hole transporting layer (hereinafter also referred to as a hole transporting material) may have any of a hole injecting property, a transporting property, and an electron barrier property. Any one can be selected and used.

  For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives , Indolocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polyvinyl carbazole, polymer materials or oligomers with aromatic amines introduced into the main chain or side chain, polysilane, conductive And polymer (for example, PEDOT / PSS, aniline copolymer, 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 linking core part.
In addition, hexaazatriphenylene derivatives such as those described in JP-A-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.
Furthermore, 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, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material or an inorganic compound such as p-type-Si or p-type-SiC, as described in the literature (Appl. Phys. Lett., 80 (2002), p. 139) is used. You can also Further, ortho-metalated organometallic complexes having Ir or Pt as the central metal as typified by Ir (ppy) ₃ are also preferably used.

Although the above-mentioned materials can be used as the hole transport material, a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organometallic complex, or an aromatic amine is introduced into the main chain or side chain. The polymer materials or oligomers used are preferably used.
Specific examples of known preferred hole transport materials used in the organic EL device of the present invention include the compounds described in the following documents in addition to the documents listed above, but the present invention is not limited thereto. Not.
For example, Appl. Phys. Lett. 69, 2160 (1996); Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. , 90, 183503 (2007), Appl. Phys. Lett. , 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. , 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. , 111, 421 (2000), SID Symposium Digest, 37, 923 (2006), J. Am. 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. U.S. Patent No. 5061569, International Publication No. 2007/002683, International Publication No. 2009/018009, EP650955, U.S. Patent Publication No. 2008/0124572, U.S. Patent Publication No. 2007/0278938, US Patent Publication No. 2008/0106190, US Patent Publication No. 2008/0018221, International Publication No. 2012/115034, Japanese Translation of PCT International Publication No. 2003-519432, Japanese Patent Laid-Open No. 2006-135145, US Patent Application Number 13/5 , And the like No. 5981.
The hole transport material may be used alone or in combination of two or more.

《Electron blocking layer》
The electron blocking layer is a layer having a function of a hole transport layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, while transporting holes. By blocking electrons, the probability of recombination of electrons and holes can be improved.
Moreover, the structure of the positive hole transport layer mentioned above can be used as an electron blocking layer used for this invention as needed.
The electron blocking layer provided in the organic EL device of the present invention is preferably provided adjacent to the anode side of the light emitting layer.
The thickness of the electron blocking layer used in the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.
As the material used for the electron blocking layer, the material used for the above-described hole transport layer is preferably used, and the material used as the above-described host compound is also preferably used for the electron blocking layer.

《Hole injection layer》
The hole injection layer (also referred to as “anode buffer layer”) used in the present invention is a layer provided between the anode and the light emitting layer in order to lower the driving voltage or improve the light emission luminance. It is described in detail in Chapter 2 “Electrode Materials” (pages 123 to 166) of the second edition of “Devices and the Forefront of Industrialization (issued by NTT Corporation on November 30, 1998)”.
In the present invention, the hole injection layer may be provided as necessary, and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.
The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of the material used for the hole injection layer include: Examples thereof include materials used for the above-described hole transport layer.

Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-T-2003-519432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon Preferred are conductive polymers such as polyaniline (emeraldine) and polythiophene, orthometalated complexes represented by tris (2-phenylpyridine) iridium complex, and triarylamine derivatives.
The materials used for the hole injection layer described above may be used alone or in combination of two or more.

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

<Method for forming organic layer>
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.) according to the present invention will be described.
The method for forming the organic layer according to the present invention is not particularly limited, and a conventionally known method such as a vacuum deposition method or a wet method (also referred to as a wet process) can be used. Is more preferable.
Examples of the wet method include spin coating, casting, ink jet, printing, die coating, blade coating, roll coating, spray coating, curtain coating, and LB (Langmuir-Blodgett). From the viewpoint of obtaining a homogeneous thin film easily and high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, or a spray coating method is preferable.

Examples of the liquid medium for dissolving or dispersing the organic EL material of the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, mesitylene, Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used.
Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

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

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

For the anode, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern of a desired shape may be formed by photolithography, or when pattern accuracy is not required (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.
In addition, when a material that can be applied, such as an organic conductive compound, is used, a wet film formation method such as a printing method or a coating method can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less.
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 material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and 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 ) Mixtures, indium, lithium / aluminum mixtures, aluminum, rare earth metals and the like. Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this from the viewpoint of durability against electron injection and oxidation, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

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 the cathode is preferably several hundred Ω / □ or less, 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, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.
Moreover, after producing the above metal with a film thickness of 1 to 20 nm on the cathode, a transparent or translucent cathode can be produced by producing a conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture a device in which both the anode and the cathode are transparent.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. Or opaque. When extracting light 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 giving 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, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Film.

An inorganic film, an organic film, or a hybrid film of both 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. , And a relative humidity (90 ± 2)%) of 0.01 g / (m ² · 24 h) or less is preferable as a gas barrier film, and oxygen measured by a method according to JIS K 7126-1987. A high gas barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the gas barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the gas barrier film is not particularly limited. For example, the 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 A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an 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, opaque resin substrates, and ceramic substrates.
The external extraction quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, and more preferably 5% or more.
Here, external extraction quantum efficiency (%) = number of photons emitted to the outside of the organic EL element / number of electrons flowed to the organic EL element × 100.
In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor.

<Sealing>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive. As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and it may be concave plate shape or flat plate shape. Moreover, transparency and electrical insulation are not particularly limited.
Specific examples 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, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

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

Specific examples of adhesives include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.
In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.

Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. There are no particular limitations on the method of forming these films. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.
In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, 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.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

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

《Light extraction enhancement technology》
An organic electroluminescence element 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 about 15% to 20% of light generated in the light emitting layer. It is generally said that only light can be extracted. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the element, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light undergoes total reflection between the light and the light, and the light is guided through the transparent electrode or the light emitting layer.

  As a technique for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the transparent substrate and the air interface (for example, US Pat. No. 4,774,435), A method for improving efficiency by providing light condensing property (for example, JP-A-63-314795), a method for forming a reflective surface on a side surface of an element (for example, JP-A-1-220394), a substrate, etc. A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), lower refraction than the substrate between the substrate and the light emitter A method of introducing a flat layer having a refractive index (for example, Japanese Patent Application Laid-Open No. 2001-202827), and a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside) JP-A-11 No. 283,751 Publication), and the like.

In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, 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, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.
In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

When a low refractive index medium is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. Become.
Examples of the low refractive index layer include aerogel, 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, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less.

The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.
The method of introducing a diffraction grating into an interface that causes total reflection or in any medium has a feature that the effect of improving the light extraction efficiency is high. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction or second-order diffraction. The light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating into any layer or medium (in the transparent substrate or transparent electrode). , Trying to extract light out.

The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only 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, light traveling in all directions is diffracted, and light extraction efficiency is increased.
The position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but 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 within a range of about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention can be processed to provide, for example, a structure on a microlens array on the light extraction side of a support substrate (substrate), or combined with a so-called condensing sheet, for example, in a specific direction, for example, device light emission. Condensing light in the front direction with respect to the surface can increase the luminance in a specific direction.
As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally on the light extraction side of the substrate. One side is preferably within a range of 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may be used.
Moreover, in order to control the light emission angle from an organic EL element, you may use a light-diffusion plate and a film together with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources.
For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.
In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during 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 layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

<Display device>
The organic EL element of the present invention can be used for a display device. The display device may be single color or multicolor, but here, the multicolor display device will be described.
In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.
In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.
Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.
When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.
Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.
Light emitting sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. However, the present invention is not limited to these.

Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.
The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, a wiring unit C that electrically connects the display unit A and the control unit B, and the like. .
The control unit B is electrically connected to the display unit A via the wiring unit C, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside. Sequentially emit light according to the image data signal, scan the image, and display the image information on the display unit A.

FIG. 3 is a schematic diagram of a display device using an active matrix method.
The display unit A includes a wiring unit C including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.
FIG. 3 shows a case where the light emitted from the pixel 3 (the emitted light L) is extracted in the direction of the white arrow (downward).

The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions (details are shown in FIG. Not shown).
When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.
Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

Next, the light emission process of the pixel will be described. FIG. 4 is a schematic diagram showing a pixel circuit.
The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 4, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, since the capacitor 13 holds the charged potential of the image data signal even if the driving of the switching transistor 11 is turned off, the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.
That is, the organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.
In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

FIG. 5 is a schematic diagram of a passive matrix display device. In FIG. 5, a plurality of scanning lines 5 and a plurality of data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.
When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.
In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.
By using the organic EL element of the present invention, a display device with improved luminous efficiency was obtained.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.
The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photocurable adhesive (LUX The track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS. A device can be formed.
FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).
FIG. 7 is a cross-sectional view of the lighting device. In FIG. 7, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes 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.

<< Organic EL element material >>
The organic EL device material of the present invention contains a compound having a structure represented by the general formula (1).
In the general formula (1), the HOMO level of B is −5.87 eV or less, the LUMO level of B is −0.24 eV or less, the substituent A ₁ and the others It is preferable that the HOMO level of the substituent A ₂ is less than −5.87 eV, and the LUMO level of the substituent A ₁ and the other substituent A ₂ satisfies the formula (I).
By using the organic EL device material of the present invention containing the compound having the structure represented by the general formula (1), the light emission efficiency is high, the driving voltage is low, the lifetime is long, and the voltage rise during driving is increased. It is possible to provide a small organic electroluminescence device that is excellent in stability over time.

  EXAMPLES 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 an Example, unless otherwise indicated, "volume%" is represented. Moreover, the structure of the comparison compounds 1-4 used in the Example below is shown.

  Moreover, the following table | surface shows the molecular calculation result of each comparative compound.

  In addition, structural formulas of compounds used in the following examples are shown.

[Example 1]
<< Production of Organic EL Element 1-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm × 100 mm × 1.1 mm glass substrate was formed as an anode on a 100 nm ITO (indium tin oxide) film, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of HT-1 is put in a molybdenum resistance heating boat, and 200 mg of HT-2 is put in another resistance heating boat made of molybdenum. 200 mg of Comparative Compound 1 is put in a resistance heating boat, 200 mg of DP-1 is put in another molybdenum resistance heating boat, 200 mg of ET-1 is put in another resistance heating boat made of molybdenum, and another molybdenum resistance heating boat is put. 200 mg of ET-2 was added and attached to a vacuum deposition apparatus.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the heating boat containing HT-1, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. An injection layer was provided.
Further, the heating boat containing HT-2 was energized and heated, and was deposited on the hole injection layer at a deposition rate of 0.1 nm / second to provide a 30 nm hole transport layer.
Further, the heating boat containing the comparative compound 1 and DP-1 was heated by energization, and co-deposited on the hole transport layer at a deposition rate of 0.1 nm / second and 0.010 nm / second, respectively, to emit light of 40 nm. A layer was provided.

Further, the heating boat containing ET-1 was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm hole blocking layer.
Further, the heating boat containing ET-2 was energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to provide a 30 nm electron transport layer.
Then, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer (cathode buffer layer), and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-10 >>
In the production of the organic EL element 1-1, the organic EL elements 1-2 to 1-10 were produced in the same manner except that the comparative compound 1 was changed to the compounds described in Table 2, Table 3-1, and Table 3-2. did. The molecular calculation results of each compound other than the comparative compound are shown in Table 3-1 and Table 3-2.

<< Evaluation of Organic EL Elements 1-1 to 1-10 >>
When evaluating the obtained organic EL elements 1-1 to 1-10, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. In addition, an epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and a lighting device as shown in FIGS. 6 and 7 was produced and evaluated.
The following evaluation was performed for each sample thus prepared.

(1) External extraction quantum efficiency The organic EL element is lit at room temperature (about 23 ° C.) under a constant current condition of ^2.5 mA / cm ² and the emission luminance [cd / m ² ] immediately after the start of lighting is measured. Thus, the external extraction quantum efficiency (η) was calculated.
Here, the measurement of light emission luminance was performed using CS-1000 (manufactured by Konica Minolta Co., Ltd.), and the external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 being 100.

(2) Half-life The half-life was evaluated according to the measurement method shown below. Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life. The half life was expressed as a relative value with the organic EL element 1-1 as 100.

(3) Driving voltage Each voltage measured when the organic EL element was driven at room temperature (about 23 ° C.) and a constant current of ^2.5 mA / cm ² was measured. The relative values are shown with 1-1 as 100.
Voltage = (drive voltage of each element / drive voltage of the organic EL element 1-1) × 100
A smaller value indicates a lower drive voltage for comparison.

(4) Voltage rise during driving The voltage when the organic EL element is driven under a constant current condition of room temperature (about 23 ° C.) and ^2.5 mA / cm ² is measured, and the calculation results are shown below. The results obtained are shown in Table 4.
It represents with the relative value which sets the organic EL element 1-1 to 100.
Voltage rise at the time of driving (relative value) = drive voltage at half brightness-initial drive voltage Note that a smaller value indicates a smaller voltage rise at the time of driving for comparison.

(5) Stability over time After storing an organic EL device at 60 ° C. and 70% RH for one month, the power efficiency before and after storage is obtained, and the respective power efficiency ratios are obtained according to the following formulas. A scale.
Stability over time (%) = power efficiency after storage / power efficiency before storage x 100
The power efficiency was determined by measuring the front luminance and luminance angle dependency of each organic EL element using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Co., Ltd.), and determining the front luminance of 1000 cd / m ² . It was. The above evaluation results are shown in Table 4.

  As is apparent from Table 4, the organic EL device using the compound having the structure represented by the general formula (1) according to the present invention is superior in luminous efficiency and luminous lifetime and low in comparison with the organic EL device of the comparative example. It was clear that it was a voltage, and it was found that the voltage rise during driving was also suppressed. It was also found that the stability over time was excellent.

[Example 2]
<< Preparation of Organic EL Element 2-1 >>
After patterning a 100 mm × 100 mm × 1.1 mm glass substrate with a 100 nm ITO film (NA45 manufactured by NH Techno Glass) as an anode, the transparent support substrate provided with this ITO transparent electrode was isopropyl alcohol. Was subjected to ultrasonic cleaning, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.
A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by HC Starck, Clevios P VP AI 4083) to 70% with pure water on the transparent support substrate. After forming a thin film by spin coating at 3000 rpm for 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a layer thickness of 20 nm.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. Meanwhile, 200 mg of HT-2 as a hole transport material is placed in a molybdenum resistance heating boat, and a comparative compound as a host compound in another molybdenum resistance heating boat. 200 mg of 1 was put, 200 mg of ET-1 as an electron transport material was put in another resistance heating boat made of molybdenum, and 100 mg of DP-2 was put as a dopant compound in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing HT-2 was energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second, and the layer thickness was 20 nm. The second hole transport layer was provided.
Furthermore, the second hole transport layer was heated by energizing the heating boat containing Comparative Compound 1 as a host compound and DP-2 as a dopant compound, respectively, at a deposition rate of 0.1 nm / second and 0.006 nm / second, respectively. A light-emitting layer having a layer thickness of 40 nm was provided by co-evaporation.

Furthermore, it supplied with electricity to the said heating boat containing ET-1, and heated, and it vapor-deposited on the said light emitting layer with the vapor deposition rate of 0.1 nm / sec, and provided the electron carrying layer with a layer thickness of 30 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.
Subsequently, lithium fluoride was vapor-deposited to form an electron injection layer having a thickness of 0.5 nm, and aluminum was vapor-deposited to form a cathode having a thickness of 110 nm. Thus, an organic EL element 2-1 was produced.

<< Production of Organic EL Elements 2-2 to 2-12 >>
In preparation of the organic EL element 2-1, the comparative compound 1 was changed to the compounds described in Table 2, Table 5-1, and Table 5-2. Other than that produced the organic EL element 2-2 to 2-12 similarly. The molecular calculation results of each compound other than the comparative compound are shown in Tables 5-1 and 5-2.

<< Evaluation of organic EL elements 2-1 to 2-12 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. The evaluation results are shown in Table 6. In addition, the measurement results of the external extraction quantum efficiency, the half life, the driving voltage, and the voltage increase during driving in Table 6 are expressed as relative values with the measured value of the organic EL element 2-1 being 100.

  As is apparent from Table 6, the organic EL device using the compound having the structure represented by the general formula (1) according to the present invention is superior in luminous efficiency and luminous lifetime and low in comparison with the organic EL device of the comparative example. It was clear that it was a voltage, and it was found that the voltage rise during driving was also suppressed. It was also found that the stability over time was excellent.

[Example 3]
<< Production of Organic EL Element 3-1 >>
Patterning was performed on a substrate (NA-45, manufactured by AvanState Co., Ltd.) on which a 100 nm ITO film was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate. Thereafter, the transparent support substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.
On this transparent support substrate, spin coating was performed using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Baytron P Al4083, Baytron P Al4083) to 70% with pure water. After forming a thin film by the method, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a layer thickness of 30 nm.

On the first hole transport layer, a hole transport material Poly (N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl)) benzidine (manufactured by American Dye Source, ADS- A thin film was formed by spin coating using the chlorobenzene solution of No. 254). Heat drying at 150 ° C. for 1 hour to provide a second hole transport layer having a layer thickness of 40 nm.
On this second hole transport layer, a thin film was formed by spin coating using Comparative Compound 1 as a host compound and DP-3 butyl acetate solution as a dopant compound, and dried by heating at 120 ° C. for 1 hour. A light emitting layer having a layer thickness of 30 nm was provided.

On this light emitting layer, a 1-butanol solution of ET-3 as an electron transporting material was used, and a thin film was formed by a spin coating method to provide an electron transporting layer having a layer thickness of 20 nm.
This substrate was attached to a vacuum deposition apparatus, and the vacuum chamber was decompressed to 4 × 10 ⁻⁴ Pa. Subsequently, lithium fluoride was vapor-deposited to form an electron injection layer having a thickness of 1.0 nm, aluminum was vapor-deposited to form a cathode having a thickness of 110 nm, and an organic EL element 3-1 was produced.

<< Production of Organic EL Elements 3-2 to 3-14 >>
In preparation of the organic EL element 3-1, the comparative compound 1 in the light emitting layer was changed to the compounds shown in Table 2 and Tables 7-1 to 7-3. Other than that produced the organic EL element 3-2 to 3-14 similarly. The molecular calculation results of each compound other than the comparative compound are shown in Tables 7-1 to 7-3.

<< Evaluation of Organic EL Elements 3-2 to 3-14 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. The evaluation results are shown in Table 8. In addition, the measurement results of the external extraction quantum efficiency, the half life, the driving voltage, and the voltage increase during driving in Table 8 are expressed as relative values with the measured value of the organic EL element 3-1 being 100.

  As is clear from Table 8, the organic EL device using the compound having the structure represented by the general formula (1) according to the present invention is superior in light emission efficiency and light emission lifetime and low in comparison with the organic EL device of the comparative example. It was clear that it was a voltage, and it was found that the voltage rise during driving was also suppressed. It was also found that the stability over time was excellent.

[Example 4]
After patterning on a substrate (NA45 manufactured by NH Techno Glass Co., Ltd.) with a 100 nm ITO film formed on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, the transparent support substrate provided with this ITO transparent electrode was made of isopropyl alcohol. Ultrasonic cleaning, drying with dry nitrogen gas, and UV ozone cleaning were performed for 5 minutes.
On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under conditions of 30 seconds and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a layer thickness of 20 nm.
The substrate was transferred to a nitrogen atmosphere, and the conditions of 1500 rpm and 30 seconds were used on the first hole transport layer using a solution of 47 mg of HT-3 and 3 mg of HT-4 in 10 ml of toluene. Below, a thin film was formed by spin coating. Ultraviolet light was irradiated at 120 ° C. for 90 seconds to perform photopolymerization / crosslinking, 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.
On this second hole transport layer, a solution of 100 mg of Comparative Compound 1 and 20 mg of DP-4, 0.5 mg of D-1, 0.2 mg of D-2 in 10 ml of butyl acetate was used for 600 rpm. A thin film was formed by spin coating under the condition of 30 seconds. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a layer thickness of about 70 nm.
Next, a thin film was formed on this light emitting layer by spin coating under a condition of 1500 rpm and 30 seconds using a solution of 50 mg of ET-4 dissolved in 10 ml of hexafluoroisopropanol (HFIP). Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a layer thickness of about 20 nm.
Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride was deposited as an electron injection layer, and further 110 nm of aluminum was deposited. Thus, a cathode was formed, and an organic EL element 4-1 was produced.

<< Production of organic EL elements 4-2 to 4-11 >>
In the production of the organic EL element 4-1, organic EL elements 4-2 to 4-11 were produced in the same manner except that the comparative compound 1 was changed to the compounds described in Table 2, Table 9-1 and Table 9-2. did. Tables 9-1 and 9-2 show the molecular calculation results of each compound other than the comparative compound.

<< Evaluation of organic EL elements 4-1 to 4-11 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. Table 10 shows the evaluation results. In addition, the measurement result of the external extraction quantum efficiency in Table 10, a half life, a drive voltage, and the voltage rise at the time of a drive was represented by the relative value which sets the measured value of the organic EL element 4-1 to 100.

  As is clear from Table 10, the organic EL device using the compound having the structure represented by the general formula (1) according to the present invention is superior in light emission efficiency and light emission lifetime and low in comparison with the organic EL device of the comparative example. It was clear that it was a voltage, and it was found that the voltage rise during driving was also suppressed. It was also found that the stability over time was excellent.

[Example 5]
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm × 100 mm × 1.1 mm glass substrate was formed as an anode on a 100 nm ITO (indium tin oxide) film, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of HT-6 is put into a resistance heating boat made of molybdenum, and 200 mg of HT-5 is put into another resistance heating boat made of molybdenum. 200 mg of Comparative Compound 1 is put into a resistance heating boat, 200 mg of DP-5 is put into another resistance heating boat made of molybdenum, 200 mg of D-3 is put into another resistance heating boat made of molybdenum, and D is put into another resistance heating boat made of molybdenum. 200 mg of -4 was put, 200 mg of ET-5 was put into another molybdenum resistance heating boat, and attached to a vacuum deposition apparatus.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the heating boat containing HT-6, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. An injection layer was provided.
Furthermore, it supplied with electricity to the said heating boat containing HT-5, it heated, and it vapor-deposited on the said positive hole injection layer with the vapor deposition rate of 0.1 nm / sec, and provided the 20-nm positive hole transport layer.

Further, the heating boat containing Comparative Compound 1, DP-5, D-3, and D-4 was energized and heated, and the deposition rates were 0.1 nm / second, 0.025 nm / second, 0.0007 nm / second, A light-emitting layer having a thickness of 60 nm was formed by co-evaporation on the hole transport layer at 0.0002 nm / second.
Further, the heating boat containing ET-5 was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 20 nm electron transport layer.
Then, 0.5 nm of potassium fluoride was vapor-deposited as an electron injection layer, and further 110 nm of aluminum was vapor-deposited, the cathode was formed, and the organic EL element 5-1 was produced.

<< Production of organic EL elements 5-2 to 5-14 >>
In the production of the organic EL element 5-1, organic EL elements 5-2 to 5-14 were produced in the same manner except that the comparative compound 1 was changed to the compounds described in Table 2, Table 11-1, and Table 11-2. did. The molecular calculation results of each compound other than the comparative compound are shown in Table 11-1 and Table 11-2.

<< Evaluation of Organic EL Elements 5-1 to 5-14 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. The evaluation results are shown in Table 12. In addition, the measurement result of the external extraction quantum efficiency in Table 12, a half life, a drive voltage, and the voltage rise at the time of a drive was represented by the relative value which sets the measured value of the organic EL element 5-1 to 100.

  As is clear from Table 12, the organic EL device in which the dopant compound of the present invention and the host compound are used in combination is clearly superior in luminous efficiency and luminous lifetime and low voltage compared to the organic EL device of the comparative example. It was also found that the voltage rise during driving was suppressed. It was also found that the stability over time was excellent.

[Example 6]
A transparent substrate with an ITO (Indium Tin Oxide) film having a thickness of 120 nm formed on a glass substrate of 50 mm × 50 mm and a thickness of 0.7 mm, patterned, and then attached with this ITO transparent electrode After ultrasonic cleaning with isopropyl alcohol, drying with dry nitrogen gas and UV ozone cleaning for 5 minutes, this transparent substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus.
Each of the resistance heating boats in the vacuum deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The resistance heating boat used was made of a resistance heating material made of molybdenum or tungsten.
After reducing the vacuum to 1 × 10 ⁻⁴ Pa, the deposition crucible containing the compound HT-1 was heated by energization, and deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / second. A hole injection layer was formed.

Next, Compound HT-2 was vapor-deposited in the same manner to form a hole transport layer having a layer thickness of 30 nm.
Subsequently, Comparative Compound 1 and DP-6 were co-deposited at a deposition rate of 0.1 nm / second so that the volume percentage was 90% and 10%, respectively, to form a light emitting layer having a layer thickness of 30 nm.
Next, ET-1 was deposited at a deposition rate of 0.1 nm / second to form a first electron transport layer having a layer thickness of 10 nm, and further ET-2 was deposited thereon at a deposition rate of 0.1 nm / second, A second electron transport layer having a layer thickness of 45 nm was formed.
Furthermore, after forming lithium fluoride with a film thickness of 1.0 nm, 100 nm of aluminum was vapor-deposited to form a cathode.
An electrode extraction wiring is installed on the above element, covered with a can-shaped glass case filled with epoxy resin in a nitrogen glove box of 1 ppm or less of water and oxygen atmosphere, a moisture absorbent is incorporated in the package, and an organic EL element 6-1 was produced.

<< Production of Organic EL Elements 6-2 to 6-12 >>
In the production of the organic EL element 6-1, the comparative compound 1 in the light emitting layer was changed to the compounds shown in Table 2, Table 13-1, and Table 13-2. Other than that produced the organic EL element 6-2 to 6-12 similarly. The molecular calculation results of each compound other than the comparative compound are shown in Table 13-1 and Table 13-2.

<< Evaluation of Organic EL Elements 6-2 to 6-12 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. The evaluation results are shown in Table 14. In addition, the measurement results of the external extraction quantum efficiency, the half life, the driving voltage, and the voltage increase during driving in Table 14 are expressed as relative values with the measured value of the organic EL element 6-1 being 100.

  As is clear from Table 14, it is clear that the organic EL device using the dopant compound of the present invention and the host compound in combination is superior in luminous efficiency and luminous lifetime and has a low voltage compared to the organic EL device of the comparative example. It was also found that the voltage rise during driving was suppressed. It was also found that the stability over time was excellent.

[Example 7]
<< Production of organic EL full-color display device >>
FIG. 8 shows a schematic configuration diagram of an organic EL full-color display device.
After patterning at a pitch of 100 μm on a substrate (NH45 manufactured by NH Techno Glass) with a 100 nm ITO transparent electrode 202 formed as an anode on a glass substrate 201 (see FIG. 8A), A non-photosensitive polyimide partition wall 203 (width 20 μm, thickness 2.0 μm) was formed between the ITO transparent electrodes 202 by photolithography (see FIG. 8B).
A hole injection layer composition having the following composition is ejected and injected on the ITO electrode 202 between the partition walls 203 using an inkjet head (manufactured by Epson Corporation; MJ800C), irradiated with ultraviolet light for 200 seconds, and 60 ° C. A hole injection layer 204 having a layer thickness of 40 nm was provided by a drying process for 10 minutes (see FIG. 8C).

A blue light-emitting layer composition, a green light-emitting layer composition, and a red light-emitting layer composition having the following compositions are similarly ejected and injected onto the hole injection layer 204 using an inkjet head, and dried at 60 ° C. for 10 minutes. Then, the light emitting layers 205B, 205G, and 205R for each color were provided (see FIG. 8D). (Hole injection layer composition)
HT-3: 20 parts by mass Cyclohexylbenzene: 50 parts by mass Isopropyl biphenyl: 50 parts by mass (blue light emitting layer composition)
Illustrative compound H5-10: 0.7 parts by mass DP-7: 0.04 parts by mass Cyclohexylbenzene: 50 parts by mass Isopropyl biphenyl: 50 parts by mass (green light emitting layer composition)
Illustrative compound H4-7: 0.7 parts by mass D-3: 0.04 parts by mass Cyclohexylbenzene: 50 parts by mass Isopropylbiphenyl: 50 parts by mass (red light emitting layer composition)
Exemplified Compound H3-10: 0.7 parts by mass D-2: 0.04 parts by mass Cyclohexylbenzene: 50 parts by mass Isopropylbiphenyl: 50 parts by mass

Next, an electron transport material is deposited so as to cover each of the light emitting layers 205B, 205G, and 205R to provide an electron transport layer (not shown) having a thickness of 20 nm, and further lithium fluoride is deposited to form a layer having a thickness of 0.6 nm. An electron injection layer (not shown) was provided, Al was vapor-deposited, and a cathode 206 having a thickness of 130 nm was provided to produce an organic EL device (see FIG. 8E).
It was found that the produced organic EL elements each emitted blue, green, and red light when a voltage was applied to the electrodes, and could be used as a full-color display device.

[Example 8]
<< Preparation of Organic EL Element 8-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm × 100 mm × 1.1 mm glass substrate was formed as an anode on a 100 nm ITO (indium tin oxide) film, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.
This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of HT-1 is put in a molybdenum resistance heating boat, and 200 mg of HT-2 is put in another resistance heating boat made of molybdenum. 200 mg of comparative compound 4 is put into a resistance heating boat, 200 mg of DP-6 is put into another resistance heating boat made of molybdenum, 200 mg of ET-1 is put into another resistance heating boat made of molybdenum, and another resistance heating boat made of molybdenum is added. 200 mg of ET-2 was added and attached to a vacuum deposition apparatus.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the heating boat containing HT-1, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. An injection layer was provided.
Further, the heating boat containing HT-2 was energized and heated, and was deposited on the hole injection layer at a deposition rate of 0.1 nm / second to provide a 30 nm hole transport layer.
Furthermore, the heating boat containing the comparative compound 4 and DP-6 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.1 nm / second and 0.010 nm / second, respectively, to emit light of 40 nm. A layer was provided.

Further, the heating boat containing ET-1 was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm hole blocking layer.
Further, the heating boat containing ET-2 was energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to provide a 30 nm electron transport layer.
Then, 0.5 nm of lithium fluoride was vapor-deposited as an electron injection layer (cathode buffer layer), and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced.

<< Production of Organic EL Element 8-2 >>
In the production of the organic EL element 8-1, an organic EL element 8-2 was produced in the same manner except that a light emitting layer was provided by the following procedure.
200 mg of Exemplified Compound H2-1 was placed in a molybdenum resistance heating boat. The heating boat containing Comparative Compound 4, Exemplified Compound H2-1 and DP-6 was energized and heated, and the deposition rates were 0.1 nm / second, 0.010 nm / second, and 0.010 nm / second, respectively. A 40 nm light emitting layer was provided by co-evaporation on the hole transport layer.

<< Production of Organic EL Elements 8-3 to 8-9 >>
Organic EL elements 8-3 to 8-9 were prepared in the same manner except that the example compound H2-1 was changed to the compounds shown in Table 15 in the preparation of the organic EL element 8-2.

<< Evaluation of Organic EL Elements 8-1 to 8-9 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-10 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated. .
Each sample thus produced was evaluated for external extraction quantum efficiency, half life, driving voltage, voltage increase during driving, and stability over time, as in Example 1. The evaluation results are shown in Table 15. In addition, the measurement result of the external extraction quantum efficiency in Table 15, half life, a drive voltage, and the voltage rise at the time of a drive was represented by the relative value which sets the measured value of the organic EL element 8-1 to 100.

  As is clear from Table 15, the organic EL device in which the compound having the structure represented by the general formula (1) according to the present invention is used in combination in the light emitting layer has a light emission efficiency and a light emission lifetime as compared with the organic EL device of the comparative example. It was clear that the voltage was excellent and low, and the increase in voltage during driving was suppressed. It was also found that the stability over time was excellent.

As described above, according to the present invention, an organic electroluminescence element, an illuminating device, and a display having high luminous efficiency, low driving voltage, long life, small voltage increase during driving, and excellent stability over time. An apparatus can be provided.
Moreover, it turned out that there exists an outstanding effect also about the organic EL element manufactured by the wet process. Furthermore, the organic EL element which has the said effect can be manufactured also by using together with another host compound for a light emitting layer.

  The organic electroluminescence device of the present invention is a display device, display, home lighting, interior lighting, clock or liquid crystal backlight, signboard advertisement, traffic light, light source of optical storage medium, electrophotographic copying, which includes an organic EL device. It can be suitably used as a wide light source such as a light source of a machine, a light source of an optical communication processor, a light source of an optical sensor, and a general household appliance requiring a display device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor 101 Organic EL element 102 in an illuminating device Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate 108 with a transparent electrode Nitrogen Gas 109 Water-absorbing agent 201 Glass substrate 202 Transparent electrode 203 Partition wall 204 Hole injection layer 205B, 205G, 205R Light emitting layer A for each color A Display unit B Control unit C Wiring unit L Light emission

Claims (15)

An organic electroluminescence device having an organic layer including a light emitting layer between at least a pair of an anode and a cathode,
The organic layer contains a compound having a structure represented by the following general formula (1).

(In General Formula (1), B represents a condensed aromatic heterocycle different from benzimidazole. A compound having a structure represented by General Formula (1) is a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. , An aromatic hydrocarbon ring group having 6 or more carbon atoms having a substituent at the ortho position, an aromatic heterocyclic group having 6 or more member rings having a substituent at the ortho position, an amino group having a substituent, and a silyl having a substituent At least one substituent A ₁ containing at least one group selected from the group consisting of a group, a phosphoryl group having a substituent and a thiophosphoryl group having a substituent, and further having another substituent A ₂ May be.) The HOMO level of B is −5.87 eV or less,
The LUMO level of B is -0.24 eV or less;
The HOMO level of the substituent A ₁ and the other substituent A ₂ is −5.87 eV or less,
The LUMO level of the substituents A ₁ and the other substituents A ₂ An organic electroluminescence device according to claim 1, characterized by satisfying the following formula (I).
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV Organic claim 1 or claim 2 wherein the substituent A ₁ or the other substituents A _2, characterized in that a substituent comprising a group or combination thereof selected from the following substituent group Electroluminescence element.
Substituent group:
Alkyl group, cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, non-aromatic heterocyclic group, aromatic heterocyclic group, cyano group, silyl group, phosphoryl group The organic electroluminescence device according to any one of claims 1 to 3, wherein B is a condensed aromatic heterocyclic group represented by the following general formula (2).

(In General Formula (2), X represents O or S. Y ₂₁ to Y ₂₈ each independently represent CH or N, and may have the substituent A ₁ or the other substituent A _2. Note that * represents a binding site in the compound having the structure represented by the general formula (1). The organic electroluminescence device according to any one of claims 1 to 3, wherein B is a condensed aromatic heterocyclic group represented by the following general formula (3).

(In General Formula (3), Y _{31 to} Y ₃₃ and Y _{35 to} Y ₃₇ each independently represent O, S, N, or CH. When N is represented, a hydrogen atom, an unshared electron pair, or a substituent is represented. Y ₃₄ or Y ₃₈ represents CH or N. Y _{31 to} Y ₃₈ may each independently have the substituent A ₁ or the other substituent A ₂ . Represents a binding site in a compound having a structure represented by the general formula (1). The organic electroluminescence device according to any one of claims 1 to 3, wherein the B is a condensed aromatic heterocyclic group represented by the following general formula (4).

In (formula _{(4), Y} 41 _{~Y 44,} the _.Y 45 _{to Y 48} which represents CH or N independently represent each independently O, S, N or CH, hydrogen if it represents a N An atom, an unshared electron pair, or a substituent group, and Y _{41 to} Y ₄₈ may each independently have the substituent group A ₁ or the other substituent group A ₂ . (Represents a binding site in a compound having the structure represented by formula (1).) The organic compound according to any one of claims 1 to 3, wherein B is a condensed aromatic heterocyclic group different from benzimidazole represented by the following general formula (5). Electroluminescence element.

(In General Formula (5), Y _{51 to} Y ₅₄ each independently represent CH or N. Y ₅₅ to Y ₅₇ each independently represent O, S, N, or CH, and hydrogen represents N. An atom, an unshared electron pair, or a substituent, Y _{51 to} Y ₅₇ may each independently have the substituent A ₁ or the other substituent A _2. Note that * (Represents a binding site in a compound having the structure represented by formula (1).) The organic electroluminescence device according to any one of claims 1 to 3, wherein the B is a condensed aromatic heterocyclic ring represented by the following general formula (6).

_(Y 61 _{to Y 66} each independently represent an O, S, N or CH, the hydrogen atom may represent N, _{.Y 67} and _{Y 68} has an unshared electron pair or substituents, CH independently Or Y _{61 to} Y ₆₆ may each independently have the substituent A ₁ or the other substituent A _2. Note that * is represented by the general formula (1). Represents a binding site in a compound having a structure. Said substituents A ₁ An organic electroluminescence device according to claim 1, any one of up to claim 8, characterized in that a substituent containing a silyl group having a substituent.   The said light emitting layer contains the compound which has a structure represented by the said General formula (1), The organic electroluminescent element as described in any one of Claim 1- Claim 9 characterized by the above-mentioned.   The organic light-emitting device according to claim 10, wherein the light-emitting layer contains an Ir complex as a phosphorescent dopant.   The organic light-emitting device according to claim 11, wherein the light emitting layer contains two or more kinds of host compounds including a compound having a structure represented by the general formula (1).   The organic electroluminescence device according to any one of claims 1 to 12, wherein the organic layer is manufactured by a wet process. An organic electroluminescence device material comprising a compound having a structure represented by the following general formula (1).

(In General Formula (1), B represents a condensed aromatic heterocycle different from benzimidazole. A compound having a structure represented by General Formula (1) is a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. , An aromatic hydrocarbon ring group having 6 or more carbon atoms having a substituent at the ortho position, an aromatic heterocyclic group having 6 or more member rings having a substituent at the ortho position, an amino group having a substituent, and a silyl having a substituent At least one substituent A ₁ containing at least one group selected from the group consisting of a group, a phosphoryl group having a substituent and a thiophosphoryl group having a substituent, and further having another substituent A ₂ May be.) The HOMO level of B is −5.87 eV or less,
The LUMO level of B is -0.24 eV or less;
The HOMO level of the substituent A ₁ and the other substituent A ₂ is −5.87 eV or less,
The organic electroluminescence device material according to claim 14 wherein the LUMO level of the substituents A ₁ and the other substituents A _2, characterized in that satisfies the following formula (I).
Formula (I): [LUMO Level of Substituent A ₁ and Other Substituent A ₂ ]> [LUMO Level of B] −0.2 eV

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