JP2017107992A - Organic electroluminescent element, display device, lighting device and organic functional material for electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescence element having high luminous efficiency, long lifetime of light emission, and particularly improved storage stability at high temperature, and a display device and a lighting device including the same.SOLUTION: The organic electroluminescence element includes organic functional layers containing a light emitting layer sandwiched between an anode and a cathode of the organic electroluminescent element. At least one layer out of the organic functional layers contains an aromatic heterocyclic derivative having a structure represented by the following general formula (1).SELECTED DRAWING: None

Description

  The present invention relates to an organic electroluminescent element, a display device, a lighting device, and an organic functional material for electronic devices. More specifically, the present invention relates to an organic electroluminescence device having high luminous efficiency, long luminous lifetime, and improved storage stability at high temperatures.

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

  Furthermore, since Princeton University reported an organic EL device that utilizes phosphorescence emission from an excited triplet, which in principle can achieve a luminous efficiency of about four times that of an organic EL device that utilizes fluorescence. 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. How to recombine within the light emitting layer to stabilize light emission is an important technical problem for increasing the efficiency and life of the device.

  Therefore, in recent years, multilayer stacked devices having 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 in a form adjacent to the light-emitting layer are well known. ing. In addition, a mixed layer using a phosphorescent compound as a light emitting dopant and a host compound is often used for the light emitting layer.

  On the other hand, from the viewpoint of materials, there is a great expectation for creating new materials for improving device performance. In particular, organic EL materials using nitrogen-containing polycondensed compounds as host compounds of phosphorescent compounds have been reported (see, for example, Patent Documents 1 and 2).

  However, when these compounds described in Patent Documents 1 and 2 are used as an organic EL device material, the lifetime of the device and the light emission efficiency are improved to some extent, but it is not sufficient, and further improvements have been demanded. Moreover, it turned out that the organic EL element using these compounds has the fault that it is inferior to thermal stability, ie, the fault that the temporal change of performance is large in the preservation | save or use under high temperature. Patent Documents 3 and 4 disclose the use of a compound having an aromatic hydrocarbon group at the 4-position and a nitrogen-containing heterocyclic group at the 6-position of dibenzofuran as an organic electronic material. Even if a compound was used, it could not be said that the preservation property at high temperature was sufficient, and further improvement was demanded.

Special table 2013-510803 gazette International Publication No. 2015/014434 US Patent Application Publication No. 2015/0259221 Korean Published Patent No. 2015-0031396

  The present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is that a novel aromatic heterocyclic derivative is used as an organic functional material, the luminous efficiency is high, the luminous lifetime is long, and particularly high temperature. It is to provide an organic electroluminescence device having improved storage stability below. Moreover, it is providing the display apparatus and illuminating device with which the said organic electroluminescent element was comprised. Furthermore, it is providing the organic functional material for electronic devices containing a novel aromatic heterocyclic derivative.

  As a result of studying the cause of the above-mentioned problem in order to solve the above-mentioned problems, the present inventors have found that an aromatic heterocyclic derivative having a specific structure is effective in solving the above-mentioned problems, and have reached the present invention.

  That is, the said subject which concerns on this invention is solved by the following means.

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

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。）
２．前記一般式（１）で表される構造を有する芳香族複素環誘導体が、下記一般式（１−１）〜（１−１６）で表される構造のうちのいずれかで表される構造を有することを特徴とする第１項に記載の有機エレクトロルミネッセンス素子。

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. R _{1 to} R ₅ are not bonded to each other to form a ring, and do not form a ring with other parts in the general formula (1), and X is an oxygen atom or a sulfur atom. Represents.)
2. The aromatic heterocyclic derivative having the structure represented by the general formula (1) has a structure represented by any one of the structures represented by the following general formulas (1-1) to (1-16). 2. The organic electroluminescence device according to item 1, characterized by comprising:

3. Ar ₁ and Ar ₂ each represent a monocyclic aryl group, The organic electroluminescent element according to item 1 or 2, wherein

4). Said R < ₁ > -R < ₅ > respectively represents a hydrogen atom, The organic electroluminescent element as described in any one of Claim ₁ to 3 characterized by the above-mentioned.

5). The R _{1 to} R ₅ each represent a hydrogen atom, and the Ar ₁ and Ar ₂ each represent a monocyclic aryl group, any one of the first to fourth items The organic electroluminescent element of the item.

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

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

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

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

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

  11. An illuminating device comprising the organic electroluminescence element according to any one of items 1 to 9.

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

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。）

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. R _{1 to} R ₅ are not bonded to each other to form a ring, and do not form a ring with other parts in the general formula (1), and X is an oxygen atom or a sulfur atom. Represents.)

  According to the present invention, an organic electroluminescence device using a novel aromatic heterocyclic derivative as an organic functional material and having high luminous efficiency, long luminous lifetime, and particularly improved storage stability at high temperatures by the above means. Can be provided. In addition, a display device and a lighting device including the organic electroluminescence element can be provided. Furthermore, the organic functional material for electronic devices containing a novel aromatic heterocyclic derivative can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  In order to use it as an electron transporting material or an electron transporting host compound, it is preferable that no exciton is generated on the compound. As a suppression means, the highest occupied molecular orbital (HOMO) of a compound having an electron transporting property is used. ) It is conceivable to lower the level (also called “deep”).

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

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

  For example, when a film is formed by vapor deposition, immediately after molecules are deposited on the film, the molecules are in a freely rotatable state, and it takes time until a stable film is formed. Further, it is presumed that the molecules move when heat is applied or when a drive voltage is applied. However, such a film with large fluctuations tends to fluctuate and there is a tendency that favorable performance cannot be obtained. For this reason, a compound having as little molecular movement in the membrane as possible is preferable.

  In the compound having the structure represented by the general formula (1) according to the present invention, there are few places where free rotation is possible. Therefore, it is speculated that even if molecules move in the film, the change of the whole film is small and stable performance can be obtained. Is done.

  In addition, a structure easily associated with a large π-conjugated surface such as triphenylene is often not preferable for the purpose of obtaining an amorphous film because of its high crystallinity, but the structure represented by the general formula (1) according to the present invention. It is considered that a compound having a does not have such a structure and thus easily forms an amorphous film.

The schematic perspective view which showed an example of the structure of the display apparatus of this invention The schematic perspective view which showed an example of the structure of the display part A shown in FIG. The schematic perspective view which shows an example of the illuminating device using the organic EL element of this invention. Schematic sectional view showing an example of a lighting device using the organic EL element of the present invention

  The organic electroluminescent element of the present invention is an organic electroluminescent element in which an organic functional layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one of the organic functional layers includes the general formula ( It contains an aromatic heterocyclic derivative having a structure represented by 1). This feature is a technical feature common to the claimed invention.

  As an embodiment of the present invention, an aromatic heterocyclic derivative having a structure represented by the general formula (1) is represented by the general formulas (1-1) to (1-16) from the viewpoint of manifesting the effects of the present invention. It is preferable to have a structure represented by any of the structures represented by

In particular, Ar ₁ and Ar ₂ each represent a monocyclic aryl group, R _{1 to} R ₅ each represent a hydrogen atom, or R _{1 to} R ₅ each represent It is preferable that each represents a hydrogen atom, and each of the Ar ₁ and Ar ₂ represents a monocyclic aryl group.

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

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

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

  Moreover, the aromatic heterocyclic derivative which has a structure represented by the said General formula (1) can be used suitably as an organic functional material for electronic devices.

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

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

（式中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、アルキル基又は単環のアリール基を表す。Ｒ_１〜Ｒ_５は、それぞれ独立に、水素原子、アルキル基、シアノ基又はフッ素原子を表す。Ｒ_１〜Ｒ_５は、互いに結合して環を形成することはない。また、一般式（１）中の他の部分と環を形成することはない。Ｘは、酸素原子又は硫黄原子を表す。）
一般式（１）中、Ａｒ_１及びＡｒ_２は、それぞれ独立に、置換若しくは無置換の炭素数１〜１２のアルキル基、又は、置換若しくは無置換の単環のアリール基（ただし、ヘテロアリール基は含まないものとする。）を表す。Ａｒ_１及びＡｒ_２は、好ましくは、置換若しくは無置換の単環のアリール基である。 <Aromatic heterocyclic derivative having a structure represented by the general formula (1)>

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. R _{1 to} R ₅ are not bonded to each other to form a ring, and do not form a ring with other parts in the general formula (1), and X is an oxygen atom or a sulfur atom. Represents.)
In General Formula (1), Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted monocyclic aryl group (however, a heteroaryl group) Is not included.) Ar ₁ and Ar ₂ are preferably a substituted or unsubstituted monocyclic aryl group.

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

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

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

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

The above alkyl group and aryl group represented by Ar ₁ or Ar ₂ may each further have a substituent as long as the function of the compound of the present invention is not impaired, and specific examples of such a substituent are as follows. Includes the same groups as the substituents represented by R _{1 to} R ₅ described later.

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

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

R _{1 to} R ₅ are not bonded to each other to form a ring. Moreover, a ring is not formed with the other part in General formula (1).

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

  Examples of these substituents include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group). Group), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group ( Also called aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group, etc., 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 Etc.), an aromatic heterocyclic group (for example, pyridyl group, pyrazyl group, pyrimidinyl group, triazyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2, 4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl 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, azacarbazolyl group (one in which any one or more of the carbon atoms constituting the carbazole ring of the carbazolyl group are replaced by nitrogen atoms) ), Quinoxalinyl group, pyridazinyl group Triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, Hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, Methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenyl) Thio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxy) Carbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecyl) Aminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethyl group) Rubonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy Group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propyl) Carbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group Dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group) Octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentyl) Ureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminouree Id group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc. ), Alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group) , Naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclope) Tilamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg. , Fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group) Group, phenyldiethylsilyl group, etc.), phosphono group and the like.

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

  X represents an oxygen atom or a sulfur atom.

In the present invention, in particular, Ar ₁ and Ar ₂ each represent a monocyclic aryl group, R _{1 to} R ₅ each represent a hydrogen atom, or R _{1 to} R _5. Each represents a hydrogen atom, and Ar ₁ and Ar ₂ each preferably represent a monocyclic aryl group.

  As embodiment of this invention, the aromatic heterocyclic derivative which has a structure represented by the said General formula (1) is a structure represented by the following general formula (1-1)-(1-16). It preferably has a structure represented by any of them.

In the above general formulas (1-1) to (1-16), Ar ₁ , Ar ₂ , R _{1 to} R ₅ and X have the same meanings as in general formula (1).

  Although the specific example of a preferable aromatic heterocyclic derivative is shown below, it is not limited to these.

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

<Synthesis example of exemplary compound>
Hereinafter, a method for synthesizing the exemplary compound 120 will be described.

  The synthesis route and synthesis method of the exemplified compound 120 are as follows. In addition, other exemplary compounds can be synthesized basically by the same method as the following synthesis method by employing appropriate raw materials and reaction conditions.

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

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

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

<Uses of aromatic heterocyclic derivatives>
The aromatic heterocyclic derivative having the structure represented by the general formula (1) according to the present invention can be used in a wide range of technical fields, but the aromatic heterocyclic derivative alone or other kinds of compounds are contained. Suitable as an organic functional material for electronic devices. For example, it can be suitably used in organic electroluminescence elements, solar cells, electrophotographic photoreceptors and the like. In particular, it can be suitably used as a functional organic material in an organic electroluminescence element.

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

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

<< Constituent layer of organic electroluminescence element >>
Examples of typical configurations of the organic functional layer and the like in the organic EL element of the present invention include the following configuration examples, but are 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 according to the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Moreover, you may be comprised by multiple layers.

  The hole transport layer according to the present invention is a layer having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Moreover, you may be comprised by multiple layers.

  In the above-described typical element configuration, the layer excluding the anode and the cathode is also referred to as “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. Two light emitting units may be the same, and the remaining one may be different.

  Further, the third light emitting unit may not be provided, 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, etc. 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-3496868, JP-A-3884564, JP-A-42131169, JP-A-2010-192719. Publication, JP 2009-076 29, JP 2008-078414, JP 2007-059848, JP 2003-272860, JP 2003-045676, WO 2005/094130, etc. Examples include constituent materials, but the present invention is not limited to these.

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light-emitting layer used in 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 the light-emitting layer. Even in the layer, it may be the interface between the light emitting layer and the adjacent layer. If the light emitting layer used for this invention satisfy | fills the requirements prescribed | regulated by this invention, there will be no restriction | limiting in particular in the structure.

  The total thickness of the light emitting layer is not particularly limited, but it prevents the uniformity of the film to be formed, the application of unnecessary high voltage during light emission, and the improvement of the stability of the emission color with respect to the driving current. From a viewpoint, it is preferable to adjust to the range of 2 nm-5 micrometers, More preferably, it adjusts to the range of 2-500 nm, More preferably, it adjusts to the range of 5-200 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 used in the present invention preferably contains a light emitting dopant (also simply referred to as a dopant) and a host compound (light emitting host, also simply referred to as “host”).

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

  The concentration of the 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 color emitted by the organic EL device of the present invention and the compound of the present invention is shown in FIG. 4.16 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 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.

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

  The phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and the phosphorescence quantum yield is Although defined as a compound of 0.01 or more at 25 ° C., a preferred 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 used in the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. Just do it.

  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 Application Publication No. 2006/0202194. No., U.S. Patent Application Publication No. 2007/0087321, U.S. Patent Application Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, 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 Application Publication No. 2002/0034656, and US Pat. No. 7,332,232. US Patent Application Publication No. 2009/0108737, US Patent Application Publication No. 2009/0039776, US Patent No. 6921915, US Patent No. 6,687,266, US Patent Application Publication No. 2007/0190359. US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/0165846, US Patent Application Publication No. 2008/0015355, US Pat. No. 7,250,226, US Pat. No. 7,396,598. Statement, rice Patent Application Publication No. 2006/0263635, U.S. Patent Application Publication No. 2003/0138657, U.S. Patent Application Publication No. 2003/0152802, U.S. Pat. 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 No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Application Publication No. 2006/0251923, US Patent Application Publication No. 2005/0260441, US Pat. No. 7,393,599. Description, US Pat. No. 7,534,505, US Pat. No. 7,445,855, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2008/0297033, US Pat. No. 7,338,722 , US special Published Patent Application No. 2002/0134984, U.S. Pat. No. 7,279,704, U.S. Patent Application Publication No. 2006/098120, U.S. Patent Application Publication No. 2006/103874, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228583, USA No. 2012/212126, JP 2012-069737, JP 2012-195554, JP 2009-114086, JP 2003-81988, JP 2002-302671. Japanese Patent Laid-Open No. 2002-363552.

  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 of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, or a metal-sulfur bond is preferable.

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

  The fluorescent dopant used in the present invention 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, the compounds described in International Publication No. 2011/156793, Japanese Patent Application Laid-Open No. 2011-213643, Japanese Patent Application Laid-Open No. 2010-93181, and the like. Is not limited to these.

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

  Preferably, it is a compound having a phosphorescence quantum yield of phosphorescence 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 electric charge, and the light emission of 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 further, the organic EL element is stable against heat generated during high temperature driving or during element driving. From the viewpoint of operating, 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 point (Tg) is a value obtained by a method based on JIS-K-7121 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 are 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 Patent Application Publication No. 2003/0175553, US Patent Application Publication No. 2006/0280965, US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0017330, US Patent Application Publication No. 2009/0030202, US Patent Application Publication No. 2005/0238919, International Publication First 001/039234, 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. 2007/2007 / No. 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 JP 2008-0749939 A, JP 2007-254297 A, European Patent No. 2034538, and the like.

《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 total thickness of the electron transport layer between 5 nm and 1 μm.

On the other hand, when the layer thickness of the electron transport layer is increased, the voltage is likely to increase. Therefore, particularly when the layer thickness is thick, the electron mobility of the electron transport layer is preferably 10 ⁻⁵ cm ² / Vs or more. .

  The material used for the electron transport layer (hereinafter referred to as an electron transport material) may be any of electron injecting or transporting properties and hole blocking properties, and can be selected from conventionally known compounds. 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 compounds such as metal complexes and metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 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, but are not limited to, compounds described in the following documents.

  US Pat. No. 6,528,187, US Pat. No. 7,230,107, US Patent Application Publication No. 2005/0025993, US Patent Application Publication No. 2004/0036077, US Patent Application Publication No. 2009/0115316 U.S. Patent Application Publication No. 2009/0101870, U.S. Patent Application Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/120855, 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 Application Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387. , International Publication No. 2006/067931, International Publication No. 2007/085652, International Publication No. 2008/114690, International Publication No. 2009/066942, International Publication No. 2009/066779, International Publication No. 2009/054253, International Publication No. Japanese Patent Publication No. 2011-086935, International Publication No. 2010/150593, International Publication No. 2010/047707, European Patent No. 2311826, Japanese Unexamined Patent Publication No. 2010-251675, Japanese Unexamined Patent Publication No. 2009-209133, Japanese Unexamined Patent Publication No. 2009. -1241 No. 4, JP 2008-277810 A, JP 2006-156445 A, JP 2005-340122 A, JP 2003-45662 A, JP 2003-31367 A, JP 2003-282270 A. Gazette, International Publication No. 2012/115034, and the like.

  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.

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

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

  Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer concerning 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. It is described in detail in Chapter 2 “Electrode Materials” (pages 123 to 166) of the second 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 nm-200 nm.

  As a material used for the hole transport layer (hereinafter referred to as a hole transport material), any material that has either a hole injection property or a transport property or an electron barrier property may be used. 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 αNPD, 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. It is also possible to use so-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC, as described in the literature (Applied Physics Letters 80 (2002), p. 139). Further, ortho-metalated organometallic complexes having Ir or Pt as a 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 preferable hole transport materials used in the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents in addition to the documents listed above.

  For example, Appl. Phys. Lett. 69, 2160 (1996), J. MoI. 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), U.S. Patent Application Publication No. 2003/0162053, U.S. Patent Application Publication No. 2002/0158242, U.S. Patent Application Publication No. 2006/0240279, U.S. Patent Application Publication No. 2008/2008. No. 0220265, US Pat. No. 5,016,569, WO 2007/002683, WO 2009/018009, EP 650955, US Patent Application Publication No. 2008/0124572, US Patent Application Publication No. 2007/0278938, U.S. Patent Application Publication No. 2008/0106190, U.S. Patent Application Publication No. 2008/0018221, International Publication No. 2012/115034, Special Table No. 2003-519432, Special Publication Open 2006-135 45 No. is US Patent Application No. 13/585981 Patent like.

  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, and transporting electrons while transporting holes. The probability of recombination of electrons and holes can be improved by blocking.

  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 layer 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 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 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 additives》
The organic layer in the present invention described above may further contain other additives.

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

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

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

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

  The formation method of the organic layer used in the present invention is not particularly limited, and a conventionally known formation method such as a vacuum deposition method or a wet method (also referred to as a wet process) can be used. Here, the organic layer is preferably a layer formed by a wet process. That is, it is preferable to produce an organic EL element by a wet process. By producing the organic EL element by a wet process, a uniform film (coating film) can be easily obtained, and effects such as the difficulty of generating pinholes can be achieved. In addition, a film | membrane (coating film) here is a thing of the state dried after application | coating by a wet process.

  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 according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used.

  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 employing a vapor deposition method 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 degree of vacuum 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 thickness of 0.1 nm to 5 μm, preferably 5 to 200 nm.

  The organic layer used in the present invention is preferably formed from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming 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, those having a work function (4 eV or more, preferably 4.5 V or more) of a metal, an alloy, an electrically conductive compound and a mixture thereof as an electrode material are preferably used. Specific examples of such electrode substances include metals such as Au, and conductive transparent materials such as 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, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern of a desired shape may be formed by a photolithography method, or when pattern accuracy is not so 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.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, 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 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 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, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, 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 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.

  In addition, after producing the above metal on the cathode with a thickness of 1 to 20 nm, a transparent or translucent cathode can be produced by producing a conductive transparent material mentioned in the description of the anode thereon. By applying the above, it is possible to manufacture a device in which both the anode and the cathode are transparent.

《Support substrate》
As a 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, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be 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 polyetherimide, polyether ketone imide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic, or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Etc.

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. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it 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 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 barrier film is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or 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, ceramic substrates, and the like.

  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 may be used in combination.

<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 of the sealing member include a glass plate, a polymer plate, and a metal plate. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film 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 permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive 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, a glass plate, a polymer plate, a metal plate, and the like similar to those used for the sealing can be used. However, a polymer film is used because it is lightweight and thin. preferable.

《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 device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

  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 world) ( JP-A-11 JP), etc. 283751 can be mentioned.

  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 grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

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

  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 is smaller than this, the effect of diffraction is generated and colored, and if it is too large, the thickness becomes too thick.

  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 also 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.

<< Applications of organic EL elements >>
The organic EL element of the present invention can be used as a display device, a display, and various light 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 device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. 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>
One embodiment of the display device of the present invention that includes the organic EL element of the present invention will be described. Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

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

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

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

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

  When a scanning signal is transmitted 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 in the same substrate on the same substrate.

《Lighting device》
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. 3 shows a schematic diagram of a 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. Without using a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas with a purity of 99.999% or higher).

  4 shows a cross-sectional view of the lighting device. In FIG. 4, 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.

  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.

  The numbers of the host compounds used in the organic EL devices of the present invention in Tables 1 to 4 are the aromatic heterocyclic derivatives having the structure represented by the general formula (1), that is, the general formula (1- This corresponds to the numbers of specific examples of the aromatic heterocyclic derivatives having the structures represented by 1) to (1-16).

<< Compound used in Examples >>
The structural formulas of the compounds used in the examples are shown below. Note that. Comparative hosts 1 to 4 are compounds described in US Patent Application Publication No. 2015/0259221, Korean Patent Publication No. 2015-0031396, International Publication No. 2015/105251 and International Publication No. 2015/014434, respectively. It is.

[Example 1]
<< Production of organic EL element >>
(1) Preparation of organic EL element 101 After forming ITO (indium tin oxide) with a thickness of 150 nm as a positive electrode on a glass substrate of 50 mm × 50 mm and a thickness of 0.7 mm and performing patterning, The transparent substrate 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, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. .

  Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The resistance heating boat was made of molybdenum or tungsten.

After reducing the vacuum to 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HI-1 was energized and heated, and deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / second. A hole injection layer was formed.

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

  Subsequently, the resistance heating boat containing the comparative host 1 and GD-1 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. A 40 nm light emitting layer was formed.

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

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

  Then, after vapor-depositing lithium fluoride so that the film thickness was 0.5 nm, 100 nm of aluminum was vapor-deposited to form a cathode, and the organic EL element 101 was produced.

  After the production, the non-light-emitting surface of the organic EL element 101 is covered with a glass case in an atmosphere of high purity nitrogen gas with a purity of 99.999% or more, and a 300 μm thick glass substrate is used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is overlaid on the cathode to be in close contact with the transparent support substrate, and irradiated with UV light from the glass substrate side, It hardened and sealed, and the illuminating device which consists of a structure as shown in FIG.3 and FIG.4 was produced, and this was made into the sample.

<< Preparation of organic EL elements 102-117 >>
In the production of the organic EL device 101, the host compounds were changed to the compounds shown in Table 1. Other than that produced the organic EL elements 102-117 similarly.

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

(1) External extraction quantum efficiency The organic EL device was energized under a constant current condition of ^2.5 mA / cm ² at room temperature (25 ° C.), and the emission luminance (L0) [cd / m ² ] immediately after the start of light emission was measured. As a result, the external extraction quantum efficiency (η) was calculated.

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

  In addition, the one where a value is large shows that it is excellent in efficiency with respect to comparison.

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

Each organic EL element was driven at a constant current with a current giving an initial luminance of 4000 cd / m ² , and a time during which the initial luminance was ½ was obtained. The half-life was expressed as a relative value with the organic EL element 101 as 100.

  In addition, the one where a value is large shows that it is excellent in durability with respect to comparison.

(3) High temperature storage stability evaluation The organic EL device is placed in a thermostatic chamber under high temperature conditions (about 50 ± 5 ° C), and the half life is evaluated under the same conditions as in the above (2) half life measurement method. Was used to calculate the heat resistance.

Heat resistance (%) = (half life at high temperature) / (half life at room temperature) × 100
In Table 1, the organic EL element 101 is expressed as a relative value with 100. A larger heat resistance value indicates higher durability against temperature changes for comparison.

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

[Example 2]
<< Production of organic EL element >>
(1) Preparation of organic EL element 201 After depositing ITO (indium tin oxide) with a thickness of 150 nm as a positive electrode on a glass substrate of 50 mm × 50 mm and a thickness of 0.7 mm and performing patterning, The transparent substrate 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, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. .

  Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The resistance heating boat was made of molybdenum or tungsten.

After reducing the vacuum to 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HI-2 was energized and heated, and deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / second. A hole injection layer was formed.

  Subsequently, HT-2 was vapor-deposited at a vapor deposition rate of 0.1 nm / second to form a 30 nm-thick hole transport layer.

  Subsequently, the resistance heating boat containing the comparative host 1 and GD-2 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. A 30 nm light emitting layer was formed.

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

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

  Then, after vapor-depositing lithium fluoride so that it might become a film thickness of 0.5 nm, 100 nm of aluminum was vapor-deposited, the cathode was formed, and the organic EL element 201 was produced.

  After the production, the non-light-emitting surface of the organic EL element 201 is covered with a glass case in an atmosphere of high purity nitrogen gas with a purity of 99.999% or more, and a 300 μm thick glass substrate is used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is overlaid on the cathode to be in close contact with the transparent support substrate, and irradiated with UV light from the glass substrate side, It hardened and sealed, and the illuminating device which consists of a structure as shown in FIG.3 and FIG.4 was produced, and this was made into the sample.

<< Production of Organic EL Elements 202-220 >>
In the production of the organic EL element 201, the host compound was changed to the host compounds shown in Table 2. Other than that produced the organic EL elements 202-220 similarly.

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

  About external extraction quantum efficiency, half life, and high temperature storage stability evaluation, it evaluated by the method similar to Example 1, and represented with each relative value which sets each characteristic value of the organic EL element 201 to 100.

  The evaluation results are shown in Table 2.

  From Table 2, the organic EL elements 205 to 220 of the present invention have higher luminous efficiency and longer emission lifetime than the organic EL elements 201 to 204 of the comparative example, and the storage stability particularly at high temperatures is improved. I understand.

Example 3
<< Production of organic EL element >>
(1) Production of organic EL element 301 After forming ITO (indium tin oxide) with a thickness of 150 nm as a positive electrode on a glass substrate of 50 mm × 50 mm and a thickness of 0.7 mm and performing patterning, The transparent substrate 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, and then the transparent substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus. .

  Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The resistance heating boat was made of molybdenum or tungsten.

After reducing the vacuum to 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HI-2 was energized and heated, and deposited on the ITO transparent electrode at a deposition rate of 0.1 nm / second. A hole injection layer was formed.

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

  Subsequently, the resistance heating boat containing the comparative host 1 and GD-3 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. A 30 nm light emitting layer was formed.

  Subsequently, HB-3 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.

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

  Then, after vapor-depositing lithium fluoride so that layer thickness may be 0.5 nm, 100 nm of aluminum was vapor-deposited, the cathode was formed, and the organic EL element 301 was produced.

  After the production, the non-light-emitting surface of the organic EL element 301 is covered with a glass case in an atmosphere of high purity nitrogen gas with a purity of 99.999% or more, and a 300 μm thick glass substrate is used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is overlaid on the cathode to be in close contact with the transparent support substrate, and irradiated with UV light from the glass substrate side, It hardened and sealed, and the illuminating device which consists of a structure as shown in FIG.3 and FIG.4 was produced, and this was made into the sample.

<< Production of Organic EL Elements 302 to 315 >>
In the production of the organic EL element 301, the host compound was changed to the host compounds shown in Table 3. Other than that produced the organic EL elements 302-315 similarly.

<< Evaluation of Organic EL Elements 301-314 >>
The following evaluation was performed for each sample.

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

  The evaluation results are shown in Table 3.

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

Example 4
<< Production of organic EL element >>
(1) Preparation of organic EL element 401 On a glass substrate having a size of 50 mm × 50 mm and a thickness of 0.7 mm, an ITO (indium tin oxide) film having a thickness of 120 nm is formed as an anode and patterned. The transparent substrate with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

  On this transparent support substrate, 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 hole injection layer having a layer thickness of 20 nm.

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

  Each of the resistance heating boats for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent material of each layer in an amount optimal for device fabrication. The resistance heating boat for vapor deposition was made of molybdenum or tungsten.

After depressurizing to a vacuum degree of 1 × 10 ⁻⁴ Pa, the resistance heating boat containing HT-2 was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / second. A hole transport layer was formed.

  Subsequently, the resistance heating boat containing the comparative host 1 and GD-1 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. A 40 nm light emitting layer was formed.

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

  On top of that, lithium fluoride was vapor-deposited to a layer thickness of 0.5 nm, and then 100 nm of aluminum was vapor-deposited to form a cathode, whereby an organic EL element 401 was produced.

  After the production, the non-light-emitting surface of the organic EL element 401 is covered with a glass case in an atmosphere of high purity nitrogen gas with a purity of 99.999% or more, and a 300 μm thick glass substrate is used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material, and this is overlaid on the cathode to be in close contact with the transparent support substrate, and irradiated with UV light from the glass substrate side, It hardened and sealed, and the illuminating device which consists of a structure as shown in FIG.3 and FIG.4 was produced, and this was made into the sample.

<< Production of Organic EL Elements 402 to 425 >>
In the production of the organic EL element 401, the host compound was changed to the host compounds shown in Table 4. Other than that produced the organic EL elements 402-425 similarly.

<< Evaluation of Organic EL Elements 401-425 >>
The following evaluation was performed for each sample.

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

  The evaluation results are shown in Table 4.

  From Table 4, the organic EL elements 405 to 425 of the present invention have higher emission efficiency and longer emission lifetime than the organic EL elements 401 to 404 of the comparative example, and the storage stability is improved particularly at high temperatures. I understand.

Example 5
<Production of full-color display device>
(1) Preparation of blue light emitting element << Preparation of organic EL element 501 >>
This ITO transparent electrode was formed by patterning a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm thick ITO (indium tin oxide) film was formed as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate. The transparent support substrate provided with 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 vapor deposition apparatus. On the other hand, 200 mg of HT-3 is placed in a molybdenum resistance heating boat, and mCP (1,3- 200 mg of bis-N carbazolylbenzene), 200 mg of HB-4 in another molybdenum resistance heating boat, 100 mg of BD-1 as a luminescent dopant in another resistance heating boat made of molybdenum, and further made of molybdenum 200 mg of ET-2 was put into a resistance heating boat and attached to a vacuum evaporation apparatus.

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

  Furthermore, the molybdenum resistance heating boat containing mCP (1,3-bis-N carbazolylbenzene) and BD-1 was energized and heated, and the deposition rates were 0.2 nm / second and 0.012 nm / second, respectively. Then, a 40 nm thick light emitting layer was provided by co-evaporation on the hole transport layer. The substrate temperature during vapor deposition was room temperature.

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

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

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

(2) Production of green light-emitting element The organic EL element 419 of Example 4 was used as a green light-emitting element.

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

  In FIG. 2, only the schematic diagram of the display part A of the produced display device is shown.

  As shown in FIG. 2, the display unit A includes a plurality of pixels 3 (light emitting color pixels in the red region, green region pixels, Blue region pixels, etc.). Each of the scanning lines 5 and the plurality of data lines 6 in the wiring portion is made of a conductive material. The scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern, and are connected to the pixels 3 at the orthogonal positions (details are not shown).

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

  It was confirmed that when the obtained full-color display device was driven, a full-color moving image display with high brightness, high durability, and excellent storage stability at high temperatures was obtained.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Transparent electrode exhausted glass substrate 108 Nitrogen gas 109 Water trapping agent

Claims (12)

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

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. R _{1 to} R ₅ are not bonded to each other to form a ring, and do not form a ring with other parts in the general formula (1), and X is an oxygen atom or a sulfur atom. Represents.) The aromatic heterocyclic derivative having the structure represented by the general formula (1) has a structure represented by any one of the structures represented by the following general formulas (1-1) to (1-16). The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device is provided.

The organic electroluminescent device according to claim 1, wherein each of Ar ₁ and Ar ₂ represents a monocyclic aryl group. Said R < ₁ > -R < ₅ > respectively represents a hydrogen atom, The organic electroluminescent element as described in any one of Claim 1- Claim 3 characterized by the above-mentioned. The R _{1 to} R ₅ each represent a hydrogen atom, and the Ar ₁ and Ar ₂ each represent a monocyclic aryl group, wherein any one of claims 1 to 4 is characterized. The organic electroluminescent element of the item.   The organic light emitting device according to any one of claims 1 to 5, wherein the light emitting layer contains the aromatic heterocyclic derivative.   The organic light-emitting device according to any one of claims 1 to 6, wherein the light emitting layer contains the aromatic heterocyclic derivative as a host compound.   The organic light emitting device according to any one of claims 1 to 7, wherein the light emitting layer contains a phosphorescent dopant.   The organic light-emitting device according to any one of claims 1 to 8, wherein the light-emitting layer further contains a host compound having a structure different from that of the aromatic heterocyclic derivative.   A display device comprising the organic electroluminescence element according to claim 1.   An illuminating device comprising the organic electroluminescent element according to any one of claims 1 to 9. An organic functional material for an electronic device comprising an aromatic heterocyclic derivative having a structure represented by the following general formula (1).

(In the formula, Ar ₁ and Ar ₂ each independently represent an alkyl group or a monocyclic aryl group. R _{1 to} R ₅ each independently represents a hydrogen atom, an alkyl group, a cyano group, or a fluorine atom. R _{1 to} R ₅ are not bonded to each other to form a ring, and do not form a ring with other parts in the general formula (1), and X is an oxygen atom or a sulfur atom. Represents.)

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