JP5250967B2 - Organic compound, charge transport material, composition for charge transport material, and organic electroluminescent device - Google Patents

Description

The present invention relates to a novel organic compound, a charge transport material comprising the organic compound, and a composition for a charge transport material containing the charge transport material.
The present invention also relates to an organic electroluminescence device having high brightness, high efficiency, and long life using a charge transport material comprising the novel organic compound.

  An electroluminescent device using an organic thin film has been developed. An electroluminescent element using an organic thin film, that is, an organic electroluminescent element, usually has an organic layer including an anode, a cathode, and at least a light emitting layer provided between both electrodes on a substrate. As the organic layer, in addition to the light emitting layer, a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, and the like are used. Usually, these layers are laminated to be used as an organic electroluminescent element. Conventionally, organic electroluminescent devices have used fluorescent light emission, but in an attempt to increase the light emission efficiency of the device, it has been studied to use phosphorescent light emission instead of fluorescent light. However, even if phosphorescence emission is used, sufficient luminous efficiency, luminance, and lifetime are not yet obtained.

  Non-Patent Document 1 proposes the following polymer compound (C-1) for the purpose of improving the solubility of polyaniline, which is a conductive polymer.

However, the polymer material such as the compound (C-1) has the following problems.
・ It is difficult to control the degree of polymerization and molecular weight distribution of polymer materials.
・ Deterioration due to terminal residues occurs during continuous driving.
・ High purity of the material itself is difficult and contains impurities.

  In addition, in order to induce charge transportability in the compound (C-1), it is necessary to dope the protonic acid after oxidation, and the doped protonic acid and counter anion may be diffused. -1) is presumed to be problematic as a charge transport material for organic electroluminescent devices.

  Non-Patent Document 1 discloses the following compound (C-2) as a model compound of the compound (C-1).

  However, since the compound (C-2) has a secondary amine moiety, it is poor in heat resistance and amorphousness, and the organic thin film containing the compound (C-2) is easily deteriorated by crystallization, aggregation or the like. Has the problem. In addition, since HOMO is localized at the secondary amine site, the compound (C-2) also has a problem of poor charge transportability.

  Patent Document 1 proposes to use the following compound (C-3) as a charge transport material for an electrophotographic photoreceptor.

  However, since the compound such as the compound (C-3) has only one aromatic ring in the group bonded to the nitrogen atom of the 1,3-dihydroimidazol-2-one ring, the heat resistance is low, There may be a problem as a charge transport material for organic electroluminescent devices.

For these reasons, there has been a demand for a material that is excellent in heat resistance and amorphousness and excellent in charge transport ability.
Japanese Patent Laid-Open No. 10-246973 Macromolecules 2003, 36, 4368-4373

  The present invention has been made in view of the above circumstances, and provides a charge transport material having excellent heat resistance and amorphousness and excellent charge transport ability, and further, organic electroluminescence with high brightness, high efficiency and long life. It aims at providing the composition for forming an element, and the organic electroluminescent element using the same.

As a result of intensive studies, the present inventors have found an organic compound having the following structure. This organic compound is excellent in heat resistance, amorphousness and charge transporting ability, has high singlet and triplet excited levels, and is excellent in solubility in an organic solvent.
Therefore, according to the organic electroluminescence device using the charge transport material composed of this organic compound and the composition for charge transport material containing the charge transport material composed of this organic compound, it has high brightness, high efficiency and long life. An organic electroluminescent device is provided.

That is, the gist of the present invention is represented by an organic compound represented by the following formula (I) (Claim 1), a charge transport material comprising the compound (Claim 6 ), or represented by the following Formula (II-2). The present invention resides in a charge transport material for an organic electroluminescence device (Claim 7 ) and a composition for a charge transport material containing the material (Claim 9 ).

Another gist of the present invention is an organic electroluminescent device having a layer containing the charge transport material in an organic electroluminescent device having an anode, a cathode, and a light emitting layer provided between both electrodes on a substrate. (Claim 11 ).

〔式中、Ａｒ^１は下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族炭化水素基、下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族複素環基、または下記置換基群Ｚから選ばれる置換基を有していてもよいアルキル基を表す。
Ａｒ^２は下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族炭化水素基、または下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族複素環基を表す。
置換基群Ｚ：芳香族炭化水素基、アルキル基及び１，３−ジヒドロイミダゾール−２−オン由来の基
Ｒ^１、Ｒ^２は各々独立に、水素原子、芳香族炭化水素基またはアルキル基を表すか、或いは、下記式（II）で表されるように、互いに結合して、置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよいベンゼン環、または置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよい含窒素芳香族六員環の環Ａ ^１ を形成する。

（式中、Ａｒ ^１ 、Ａｒ ^２ 、Ｑは、前記式（Ｉ）におけると同義である。
環Ａ ^１ は、置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよいベンゼン環、または置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよい含窒素芳香族六員環を表す。）
Ｑは下記式（Ｉ−１）で表される。

（式中、Ａｒ^３〜Ａｒ ^４ は各々独立に、下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族炭化水素基、または下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族複素環基を表す。Ａｒ^３とＡｒ^４は互いに結合して環を形成していてもよい。
置換基群Ｚ：芳香族炭化水素基、アルキル基及び１，３−ジヒドロイミダゾール−２−オン由来の基）〕

[Wherein, Ar ¹ is represented by the following substituent an aromatic optionally having a substituent selected from the group Z hydrocarbon group, an aromatic heterocyclic which may have a substituent selected from Substituent Group Z It represents a cyclic group or an alkyl group which may have a substituent selected from the following substituent group Z.
The Ar ² is represented by the following aromatic optionally having a substituent selected from substituent group Z hydrocarbon group or an aromatic optionally having a substituent selected from Substituent Group Z heterocyclic group, Represent.
Substituent group Z: groups R ¹ and R ² derived from an aromatic hydrocarbon group, an alkyl group and 1,3-dihydroimidazol-2-one each independently represent a hydrogen atom , an aromatic hydrocarbon group or an alkyl group . Alternatively, as represented by the following formula (II), they are bonded to each other and may have an aromatic hydrocarbon group and / or an alkyl group as a substituent, or aromatic as a substituent It has a hydrocarbon group and / or an alkyl group to form a ring a ¹ of the nitrogen-containing aromatic six-membered ring.

(In the formula, Ar ¹ , Ar ² and Q have the same meanings as in the formula (I)).
Ring A ¹ includes a benzene ring which may have an aromatic hydrocarbon group and / or an alkyl group as a substituent, or an aromatic hydrocarbon group and / or an alkyl group which may have a substituent. Represents a nitrogen aromatic six-membered ring. )
Q is represented by the following formula (I-1 ) .

(In the formula, Ar ^{3 to} Ar ⁴ each independently has an aromatic hydrocarbon group which may have a substituent selected from the following substituent group Z , or a substituent selected from the following substituent group Z. And Ar ³ and Ar ⁴ may be bonded to each other to form a ring.
Substituent group Z: aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one-derived group )]

〔式中、環Ａ^１は、置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよいベンゼン環、または置換基として芳香族炭化水素基及び／又はアルキル基を有していてもよい含窒素芳香族六員環を表す。
Ａｒ^１、Ａｒ^９は各々独立に、下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族炭化水素基、または下記置換基群Ｚから選ばれる置換基を有していてもよい芳香族複素環基を表す。
置換基群Ｚ：芳香族炭化水素基、アルキル基及び１，３−ジヒドロイミダゾール−２−オン由来の基〕

Wherein ring A ¹ is has an aromatic hydrocarbon group and / or a benzene ring which may have an alkyl group or an aromatic as a substituent a hydrocarbon group and / or an alkyl group, as a substituent Represents a nitrogen-containing aromatic six-membered ring which may be
Ar ^1, Ar ⁹ each independently have a substituent selected from the following substituent an aromatic optionally having a substituent selected from the group Z hydrocarbon group or the following substituent group Z, Represents a good aromatic heterocyclic group.
Substituent group Z: group derived from aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one ]

  According to the organic compound of the present invention, the charge transport material comprising the compound, and the composition for a charge transport material containing the material, a uniform organic thin film containing a material having a high charge transport ability can be formed by a wet film forming method. It is possible to easily increase the area of the organic electroluminescent element. Furthermore, according to the organic electroluminescent element using the charge transport material of the present invention and the composition for a charge transport material containing the material, light can be emitted with a low voltage and high efficiency.

  Further, the charge transport material of the present invention can be applied to both the vacuum deposition method and the wet film forming method because of excellent film forming property, charge transporting property, light emitting property, and heat resistance.

  In addition, the charge transport material of the present invention and the composition for charge transport material containing the material have excellent film-forming properties, charge transport properties, light emission characteristics, and heat resistance, and therefore, in accordance with the layer structure of the element, a hole injection material. It can also be applied as a hole transport material, a light emitting material, a host material, an electron injection material, an electron transport material and the like.

  Therefore, the organic electroluminescence device of the present invention using the charge transport material of the present invention and the composition for charge transport material containing the material is a flat panel display (for example, for OA computer or wall-mounted TV), in-vehicle display device, mobile phone. It can be applied to light sources (for example, light sources for copiers, liquid crystal displays and instrument backlights), display boards, and sign lamps that take advantage of the characteristics of displays and surface light emitters, and have great technical value. It is.

  The charge transport material of the present invention and the charge transport material composition containing the material have intrinsically excellent redox stability, and thus are not limited to organic electroluminescent devices, but also electrophotographic photoreceptors, photoelectric conversions. It can also be effectively used for elements, organic solar cells, organic rectifying elements, and the like.

  Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. It is not specified in the contents.

[Organic compounds]
The organic compound of the present invention is represented by the following formula (I).

〔式中、Ａｒ^１は置換基を有していてもよい芳香族炭化水素基、置換基を有していてもよい芳香族複素環基、または置換基を有していてもよいアルキル基を表す。
Ａｒ^２は置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。
Ｒ^１、Ｒ^２は各々独立に、水素原子または置換基を表す。Ｒ^１とＲ^２は互いに結合して環を形成していてもよい。
Ｑは下記式（Ｉ−１）または（Ｉ−２）で表される。

（式中、Ａｒ^３〜Ａｒ^５は各々独立に、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。Ａｒ^３とＡｒ^４は互いに結合して環を形成していてもよい。）〕

[In the formula, Ar ¹ represents an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or an alkyl group which may have a substituent. Represent.
Ar ² represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.
R ¹ and R ² each independently represents a hydrogen atom or a substituent. R ¹ and R ² may be bonded to each other to form a ring.
Q is represented by the following formula (I-1) or (I-2).

(In the formula, Ar ^{3 to} Ar ⁵ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ³ and Ar ⁴ may be bonded to each other to form a ring.)]

[1] Structural features Since the organic compound of the present invention has a 5-membered ring (1,3-dihydroimidazol-2-one) structure containing a urea bond (-NR-CO-NR'-), It has polarity, high amorphousness, and high heat resistance. Therefore, it is possible to form an amorphous organic thin film that is soluble in various organic solvents and does not easily crystallize. Further, since the structure is a rigid planar structure, the organic compound of the present invention has high singlet and triplet excited levels. In addition to the structure, the organic compound of the present invention has a tertiary amine moiety (—Ar ² —N (Ar ³ ) —Ar ⁴ ) or two directly bonded aromatic groups (—Ar ² —Ar ⁵ ). Therefore, charge transportability and heat resistance are further improved.

[2] Molecular weight range The molecular weight of the organic compound of the present invention is usually 5000 or less, preferably 3000 or less, more preferably 2000 or less, and usually 300 or more, preferably 500 or more, more preferably 600 or more.
If the molecular weight exceeds the upper limit, purification may become difficult due to the high molecular weight of impurities, and if the molecular weight falls below the lower limit, the glass transition temperature, the melting point, the vaporization temperature, etc. will decrease. There is a risk that the properties are significantly impaired.

[3] Physical Properties The organic compound of the present invention usually has a glass transition temperature of 40 ° C. or higher, but is preferably 80 ° C. or higher and more preferably 110 ° C. or higher from the viewpoint of heat resistance.
The organic compound of the present invention usually has a vaporization temperature of 300 ° C. or higher and 800 ° C. or lower.

  The organic compound of the present invention usually has an energy difference between an excited triplet state and a ground state of 2.0 eV or more and 4.0 eV or less. However, from the viewpoint of improving the efficiency of an organic electroluminescent device using phosphorescence emission, The energy difference between the term state and the ground state is preferably 2.3 eV or more, more preferably 2.6 eV or more, and still more preferably 2.9 eV or more.

The method for obtaining the energy difference between the excited triplet state and the ground state (minimum triplet excitation energy) is, for example, as follows.
For the lowest triplet excitation energy, a solution in which a sample compound is dissolved in a spectroscopically purified solvent (for example, 2-methyltetrahydrofuran) is placed in a cylindrical quartz cell, and cooled to 77 K using liquid nitrogen to effect photoluminescence. Measured and determined from the phosphorescence emission (0, 0 transition peak shape) of the maximum energy. Separation of phosphorescence emission and fluorescence emission is performed by delaying the photoluminescence observation start time after the excitation light is incident. The photoluminescence is measured by applying an N ₂ laser light source (wavelength 337 nm) to the sample compound as excitation light in accordance with the absorption of the material.

[4] R ¹ , R ²
R ¹ and R ² in the organic compound of the present invention each independently represent a hydrogen atom or an arbitrary substituent, and R ¹ and R ² may be bonded to each other to form a ring.
As an arbitrary substituent, the organic group etc. which are illustrated below are mentioned, Preferably the group of molecular weight 500 or less is mentioned. Specific examples include the following.
An alkyl group which may have a substituent (preferably a linear or branched alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, tert -Butyl group and the like).
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl and 1-butenyl groups);
An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms, such as ethynyl and propargyl groups);
An aralkyl group which may have a substituent (preferably an aralkyl group having 7 to 15 carbon atoms, such as a benzyl group);
An optionally substituted amino group [preferably an alkylamino group having one or more optionally substituted alkyl groups having 1 to 8 carbon atoms (for example, methylamino, dimethylamino, diethylamino, Dibenzylamino group, etc.),
An arylamino group having an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent (for example, phenylamino, diphenylamino, ditolylamino group, etc.);
A heteroarylamino group having a 5- or 6-membered aromatic heterocyclic ring which may have a substituent (for example, pyridylamino, thienylamino, dithienylamino group, etc.);
An acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent (for example, acetylamino, benzoylamino group and the like)],
An alkoxy group which may have a substituent (preferably an alkoxy group having 1 to 8 carbon atoms which may have a substituent, for example, methoxy, ethoxy, butoxy group, etc.),
An aryloxy group which may have a substituent (preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy group and the like. ),
A heteroaryloxy group which may have a substituent (preferably one having a 5- or 6-membered aromatic heterocyclic group, for example, pyridyloxy, thienyloxy group, etc.),
An acyl group which may have a substituent (preferably an acyl group having 2 to 10 carbon atoms which may have a substituent, such as formyl, acetyl and benzoyl groups);
An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, for example, methoxycarbonyl, ethoxycarbonyl group and the like),
An aryloxycarbonyl group which may have a substituent (preferably an aryloxycarbonyl group having 7 to 13 carbon atoms which may have a substituent, such as a phenoxycarbonyl group);
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms which may have a substituent, such as an acetoxy group);
Halogen atoms (especially fluorine or chlorine atoms),
Carboxyl group,
A cyano group,
Hydroxyl group,
Mercapto group,
An alkylthio group which may have a substituent (preferably an alkylthio group having 1 to 8 carbon atoms, such as a methylthio group and an ethylthio group);
An arylthio group which may have a substituent (preferably an arylthio group having 6 to 12 carbon atoms, such as a phenylthio group and a 1-naphthylthio group);
A sulfonyl group which may have a substituent (for example, a mesyl group, a tosyl group, etc.),
A silyl group which may have a substituent (for example, a trimethylsilyl group, a triphenylsilyl group, etc.),
An optionally substituted boryl group (for example, a dimesitylboryl group),
A phosphino group which may have a substituent (for example, a diphenylphosphino group);
An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc. And a monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-5 condensed ring).
Heterocyclic group which may have a substituent (for example, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole Ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine Ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring, imidazolinone ring, benzimidazolinone ring, etc. Condensation It includes a monovalent group derived from a.)

  Moreover, when the said substituent further has a substituent, the said exemplary substituent is mentioned as the substituent.

As R ¹ and R ² , an aromatic hydrocarbon group which may have a substituent is preferable from the viewpoint of improving electrochemical durability and heat resistance, and has a substituent. The phenyl group may be more preferably an unsubstituted phenyl group or a mono- or di-substituted phenyl group.

As R ¹ and R ² , an alkyl group which may have a substituent is preferable from the viewpoint of further improving solubility and amorphousness, and a methyl group, ethyl group, n-propyl group, 2-propyl group is preferable. C1-C4 alkyl groups, such as a group, n-butyl group, isobutyl group, and tert-butyl group, are more preferable, and a methyl group, an ethyl group, and an n-propyl group are more preferable.

Moreover, as R < ¹ >, R < ² >, a hydrogen atom is preferable from a viewpoint of preventing the fall of a triplet excitation level.

From the viewpoint of further improving the heat resistance, R ¹ and R ² are preferably bonded to each other to form a ring. Examples of the organic compound represented by the formula (I) when R ¹ and R ² are bonded to each other to form a ring are shown below, but the present invention is not limited thereto. In the following, examples of R include the substituents and hydrogen atoms exemplified as R ¹ and R ² .

From the viewpoint of improving electrochemical durability and preventing the reduction of the triplet excited level, R ¹ and R ² are preferably bonded to each other to form a benzene ring or a nitrogen-containing aromatic six-membered ring. That is, the organic compound of the present invention is preferably represented by the following formula (II).

〔式中、Ａｒ^１、Ａｒ^２、Ｑは、前記式（Ｉ）におけると同義である。
環Ａ^１は、置換基を有していてもよいベンゼン環、または置換基を有していてもよい含窒素芳香族六員環を表す。〕

[In the formula, Ar ¹ , Ar ² and Q have the same meanings as in the formula (I).
Ring A ¹ represents a benzene ring which may have a substituent, or a nitrogen-containing aromatic six-membered ring which may have a substituent. ]

The nitrogen-containing aromatic six-membered ring of ring A ^1, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, and, in particular, a pyridine ring is preferable.

Examples of substituents on the ring A ^1, include substituents exemplified as R ^1, R ^2, preferred substituents are the same as the preferred substituents as R ^1, R ^2.

[5] Ar ¹ , Ar ²
Ar ¹ in the organic compound of the present invention represents an aromatic hydrocarbon group which may have an arbitrary substituent, an aromatic heterocyclic group which may have an arbitrary substituent, or an arbitrary substituent. Represents an optionally substituted alkyl group, and Ar ² represents an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. Represent.

Examples of the substituent that Ar ¹ and Ar ² may have include the substituents exemplified as R ¹ and R ² . The substituents for Ar ¹ and Ar ² may be formed by linking a plurality of substituents exemplified as R ¹ and R ² . These substituents may be bonded to an adjacent group to form a ring. Ar ^1, including its substituents, preferably has a molecular weight of 3000 or less, more preferably 1000 or less. Ar ² -Q, including the substituents thereof, preferably has a molecular weight of 3000 or less, preferably 1000 or less.

The substituent that Ar ¹ and Ar ² may have is preferably an aromatic hydrocarbon group that may have a substituent, more preferably a substituent, from the viewpoint of improving heat resistance. An optionally substituted phenyl group, and more preferably an unsubstituted phenyl group or a mono- or disubstituted phenyl group.

The substituent that Ar ¹ and Ar ² may have is preferably an alkyl group that may have a substituent, more preferably a methyl group, from the viewpoint of further improving solubility and amorphousness. , Ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like, more preferably methyl group, ethyl group It is.

As the substituent that Ar ¹ and Ar ² may have, 1,3-dihydroimidazole can be used from the viewpoint of further improving the heat resistance and charge transporting capability while preventing a decrease in singlet and triplet excited levels. A group derived from a 2-one ring is preferred.

Examples of aromatic hydrocarbon groups applicable to Ar ¹ and Ar ² include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, Examples thereof include a group derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as an acenaphthene ring and a fluoranthene ring.

Examples of aromatic heterocyclic groups applicable to Ar ¹ and Ar ² are furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, Carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring , Pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. It includes monocyclic or 2-4 fused ring group derived from the.

Examples of the alkyl group applicable to Ar ¹ include alkyl having 1 to 4 carbon atoms such as methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, sec-butyl group, and tert-butyl group. Groups.

Ar ¹ has a group derived from a benzene ring which may have a substituent, a group derived from a pyridine ring which may have a substituent, and a substituent from the viewpoint of preventing a decrease in triplet excited level. Groups (for example, biphenyl group, terphenyl group, phenylpyridyl group, bipyridyl group, terpyridyl group) in which a plurality of (for example, 2 to 10) pyridine rings which may have a substituent may be connected. Etc.) is preferable.
Ar ¹ is preferably the same as —Ar ² —Q from the viewpoint that synthesis is easy and the triplet excited level tends to be high.
Ar ¹ is preferably a group different from -Ar ² -Q from the viewpoint of improving solubility.

Ar ² has a group derived from a benzene ring which may have a substituent, a group derived from a pyridine ring which may have a substituent, and a substituent from the viewpoint of preventing a decrease in triplet excitation level. Divalent groups (for example, biphenyl, terphenyl, bipyridyl, terpyridyl, phenylpyridine, diphenyl) in which a plurality of (for example, 2 to 10) pyridine rings which may have a substituent may be connected. Divalent groups derived from pyridine and dipyridylbenzene are preferred.
Ar ² is a p-phenylene group, a 4,4′-biphenylene group, a 4,3′-biphenylene group, or a 3,4′-biphenylene group from the viewpoint of further improving electrochemical durability. Further preferred.

Ar ² is more preferably an m-phenylene group or a 3,3′-biphenylene group from the viewpoint of further improving the solubility.
Ar ² preferably contains a pyridine ring from the viewpoint of further improving the charge (electron) transport property, and is a divalent group derived from a pyridinediyl group or bipyridyl, terpyridyl, phenylpyridine, diphenylpyridine, or dipyridylbenzene. More preferably, it is a group.

It is preferable that both Ar ¹ and Ar ² are groups derived from a benzene ring from the viewpoints of solubility and heat resistance, and prevention of lowering of the triplet excited level.
That is, the organic compound of the present invention is preferably represented by the following formula (III).

〔式中、Ｒ^１、Ｒ^２、Ｑは、前記式（Ｉ）におけると同義である。
環Ｂ^１は置換基を有していてもよいベンゼン環を表し、環Ｃ^１はＱ以外に置換基を有していてもよいベンゼン環を表す。〕

[Wherein, R ¹ , R ² and Q have the same meanings as in the formula (I).
Ring B ¹ represents a benzene ring which may have a substituent, and ring C ¹ represents a benzene ring which may have a substituent other than Q. ]

Examples of substituents that ring B ¹ and ring C ¹ may have and preferred examples thereof are the same as the substituents that Ar ¹ and Ar ² may have.

In addition, it is preferable that both Ar ¹ and Ar ² are groups derived from a pyridine ring from the viewpoint of charge transportability and heat resistance, and prevention of lowering of the triplet excited level.
That is, the organic compound of the present invention is preferably represented by the following formula (III-2).

〔式中、Ｒ^１、Ｒ^２、Ｑは、前記式（Ｉ）におけると同義である。
環Ｄ^１は置換基を有していてもよいピリジン環を表し、環Ｅ^１はＱ以外に置換基を有していてもよいピリジン環を表す。〕

[Wherein, R ¹ , R ² and Q have the same meanings as in the formula (I).
Ring D ¹ represents a pyridine ring which may have a substituent, and ring E ¹ represents a pyridine ring which may have a substituent other than Q. ]

Examples of substituents that ring D ¹ and ring E ¹ may have and preferred examples thereof are the same as the substituents that Ar ¹ and Ar ² may have.

[6] Q
Q in the organic compound of the present invention represents a group selected from the following formula (I-1) or (I-2).

〔式中、Ａｒ^３〜Ａｒ^５は各々独立に、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。Ａｒ^３とＡｒ^４は互いに結合して環を形成していてもよい。〕

[Wherein, Ar ^{3 to} Ar ⁵ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ³ and Ar ⁴ may be bonded to each other to form a ring. ]

Examples of the substituent that Ar ^{3 to} Ar ⁵ may have include the substituents exemplified as R ¹ and R ² .

Preferable examples of the substituent that Ar ^{3 to} Ar ⁵ may have are the same as the preferable examples of the substituent that Ar ¹ and Ar ² may have.

Examples of the aromatic hydrocarbon group and aromatic heterocyclic group applicable to Ar ^{3 to} Ar ⁵ are the same as the examples of the aromatic hydrocarbon group and aromatic heterocyclic group applicable to Ar ¹ and Ar ^2. .

Ar ³ and Ar ⁴ are preferably an aromatic hydrocarbon group which may have a substituent, more preferably a substituent, from the viewpoint of improving electrochemical durability and improving heat resistance. An optionally substituted phenyl group, and more preferably an unsubstituted phenyl group or a mono- or disubstituted phenyl group.

From the viewpoint of further improving the charge transport ability, Q is preferably represented by the formula (I-1).
In Formula (I-1), Ar ³ and Ar ⁴ may be bonded to each other to form a ring that may have a substituent. Preferred examples of Ar ³ Ar ⁴ N— in the case where Ar ³ and Ar ⁴ are bonded to each other to form a ring are shown below. Among these, an N-carbazolyl group is more preferable because it has a high triplet excited level.

  From the viewpoint of improving heat resistance, Q is preferably represented by the formula (I-2).

In the formula (I-2), Ar ⁵ is a group derived from a benzene ring which may have a substituent and a plurality of benzene rings (for example, 2 to 10) from the viewpoint of preventing a decrease in triplet excitation level. Linked groups (for example, biphenylene group, terphenylene group, etc.) are preferred.

[7] Preferred Structure The organic compound of the present invention is preferably represented by the following formula (IV) from the viewpoint of having a high charge transporting ability, a high electrochemical stability, and a high triplet excited level.

〔式中、Ａｒ^２〜Ａｒ^４、Ｒ^１、Ｒ^２は、前記式（Ｉ）および式（Ｉ−１）におけると同義である。
Ａｒ^６〜Ａｒ^８は各々独立に、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。Ａｒ^７とＡｒ^８は互いに結合して環を形成していてもよい。〕

^{Wherein, Ar 2 ~Ar 4, R 1} , R 2 have the same meanings as in the formula (I) and formula (I-1).
Ar ^{6 to} Ar ⁸ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ⁷ and Ar ⁸ may be bonded to each other to form a ring. ]

Examples of Ar ⁶ and preferred examples thereof are the same as those of Ar ² . Examples and preferred examples of Ar ⁷ and Ar ⁸ are the same as Ar ^{3 and} Ar ⁴ , respectively.

Further, from the viewpoint of further improving the heat resistance while maintaining a high triplet excitation level, the organic compound of the present invention has the following formula at the site of Ar ¹ , the site of Ar ² -Q, the site of R ¹ or R ^2. It is preferable to have one or more, preferably 1 to 6, and more preferably 2 to 4, N-carbazolyl groups represented by (I-3). The carbazolyl group may have a substituent, but is preferably unsubstituted.

[8] Illustrative Examples Preferred specific examples of the organic compound of the present invention are shown below, but the present invention is not limited thereto.

[9] Synthesis Method The organic compound of the present invention can be synthesized by selecting a raw material according to the structure of the target compound and using a known method.
For example, it can be synthesized by the following procedure.

First, a 2-hydroxyimidazole derivative represented by formula (i) and a halide (Ar ¹ -X ¹ ) are transition metals such as copper powder, copper (I) halide, copper (I) oxide, and palladium complex. Catalyst (about 0.001 to 5 equivalents relative to the halogen atom of the halide (Ar ¹ -X ¹ )) and a base such as potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert-butoxy sodium, triethylamine In the presence of an organic substance (about 1 to 10 equivalents relative to the halogen atom of the halide (Ar ¹ -X ¹ )), in an inert gas stream, no solvent, or in a solvent such as an aromatic solvent or an ether solvent, A compound represented by the following formula (ii) is obtained by stirring and mixing at 20 to 300 ° C. for 1 to 60 hours. Next, the compound represented by the following formula (ii) and the halide (X ² —Ar ² —Q) are converted into transition metals such as copper powder, copper (I) halide, copper (I) oxide, and palladium complex. catalyst (0.001 equivalents with respect to halogen atoms of the halide ^{(X 2 -Ar 2 -Q))} , and potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert- butoxy sodium and triethylamine in the presence of a basic substance (10 equivalents relative to the halogen atoms of the halide ^{(X 2 -Ar 2 -Q))} , an inert gas stream, neat or, aromatic solvents, ether solvents, such as The organic compound of the present invention represented by the following formula (I) is obtained by stirring and mixing at 20 to 300 ° C. for 1 to 60 hours. In the following, Ar ^{1 to} Ar ⁵ , R ¹ , R ² and Q have the same meanings as in the formula (I). X ¹ and X ² represent a halogen atom.

  As a synthesis method of the compound represented by the above formula (ii), Tetrahedron 1999, 55, 475-484, Tetrahedron Letters 2000, 41, 6387-6391, Tetrahedron 1990, 46, 1331-1342, Forms a 5-membered ring (1,3-dihydroimidazol-2-one) containing a urea bond as described in European Journal of Organic Chemistry 1998, 183-187, The Journal of Organic Chemistry 2004, 69, 7752-7754 It is also possible to apply this method.

When Q = Ar ⁵ , the halide (X ² —Ar ² —Ar ⁵ ) can be synthesized using a known coupling reaction. As a known coupling method, specifically, “Palladium in Heterocyclic Chemistry: A guide for the Synthetic Chemist” (2nd edition, 2002, Jie Jack Li and Gordon W. Gribble, Pergamon), “Transition metal is Developed organic synthesis, its various reaction forms and latest results "(1997, Kenjiro, Kagaku Dojinsha)," Bolhard Shore Modern Organic Chemistry "(2004, KPCVollhardt, Kagaku Dojinsha) etc. In addition, a coupling reaction between rings such as a coupling reaction between an aryl halide and an aryl borate can be used.

Q = ^NAr For 3 Ar ^4, halide ^{(X 2 -Ar 2 -NAr 3 Ar} 4) , as the following equation, secondary amine compound ^(Ar 3 Ar 4 NH) and dihalide ^(X 2 -Ar ^2- X ³ (X ² , X ³ = F, Cl, Br, I)). Usable reagents and the like are the same as in the step of synthesizing the compound represented by formula (ii) from the compound represented by formula (i).

  As a purification method of the synthesized compound, “Separation and purification technology handbook” (1993, edited by The Chemical Society of Japan), “High-level separation of trace components and difficult-to-purify substances by chemical conversion method” (1988, ) Issued by IPC), or the methods described in the section “Separation and purification” in “Experimental Chemistry Course (4th edition) 1” (1990, edited by The Chemical Society of Japan) Is available.

  Specifically, extraction (including suspension washing, boiling washing, ultrasonic washing, acid-base washing), adsorption, occlusion, melting, crystallization (including recrystallization from solvent, reprecipitation), distillation (atmospheric pressure) Distillation, vacuum distillation), evaporation, sublimation (atmospheric pressure sublimation, vacuum sublimation), ion exchange, dialysis, filtration, ultrafiltration, reverse osmosis, pressure osmosis, zone lysis, electrophoresis, centrifugation, flotation separation, sedimentation separation, Magnetic separation, various chromatography (shape classification: column, paper, thin layer, capillary. Mobile phase classification: gas, liquid, micelle, supercritical fluid. Separation mechanism: adsorption, distribution, ion exchange, molecular sieve, chelate, gel filtration , Exclusion, affinity) and the like.

The product confirmation and purity analysis methods include gas chromatograph (GC), high performance liquid chromatograph (HPLC), high speed amino acid analyzer (AAA), capillary electrophoresis measurement (CE), size exclusion chromatograph (SEC), Gel permeation chromatograph (GPC), cross-fractionation chromatograph (CFC) mass spectrometry (MS, LC / MS, GC / MS, MS / MS), nuclear magnetic resonance apparatus (NMR ( ¹ HNMR, ¹³ CNMR)), Fourier transform Infrared spectrophotometer (FT-IR), UV-visible near-infrared spectrophotometer (UV.VIS, NIR), electron spin resonance apparatus (ESR), transmission electron microscope (TEM-EDX), electron beam microanalyzer (EPMA), Metal element analysis (ion chromatography, inductively coupled plasma-emission spectroscopy (ICP-AES) atomic absorption analysis) (AAS) X-ray fluorescence analyzer (XRF)), non-metallic element analysis, trace component analysis (ICP-MS, GF-AAS, GD-MS) and the like can be applied as necessary.

[10] Use of organic compound Since the organic compound of the present invention has high charge transportability, it is suitable as a charge transport material for an electrophotographic photosensitive member, an organic electroluminescent device, a photoelectric conversion device, an organic solar cell, an organic rectifying device, and the like. Can be used for
In addition, since it has a high triplet excitation level, an organic electroluminescent device that has excellent heat resistance and can be stably driven (emitted) for a long period of time by using the charge transport material of the present invention made of the organic compound of the present invention. Since it is obtained, the organic compound and the charge transport material of the present invention are particularly suitable as an organic electroluminescent element material.

[Charge transport material]
The charge transport material of the present invention is composed of the organic compound of the present invention or is represented by the following formula (II-2), preferably 2.0% by weight or more, more preferably based on toluene. Dissolves 5.0% by weight or more.

〔式中、環Ａ^１は、置換基を有していてもよいベンゼン環、または置換基を有していてもよい含窒素芳香族六員環を表す。
Ａｒ^１、Ａｒ^９は各々独立に、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。〕

[Wherein, ring A ¹ represents a benzene ring which may have a substituent, or a nitrogen-containing aromatic six-membered ring which may have a substituent.
Ar ¹ and Ar ⁹ each independently represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent. ]

In the above formula (II-2), ring ^A 1, Ar ¹ has the same meaning as ^A 1, Ar ¹ in the formula (II), the substituent, the same applies to its preferred embodiment. Ar ⁹ may be the same as Ar ^1, and the substituent that Ar ⁹ may have is the same as the substituent that Ar ¹ may have.

The molecular weight of the charge transport material of the present invention represented by the above formula (II-2) is usually 5000 or less, preferably 3000 or less, more preferably 2000 or less, and usually 300 or more, preferably 500 or more and more. Preferably it is 600 or more.
If the molecular weight exceeds the upper limit, purification may become difficult due to the high molecular weight of impurities, and if the molecular weight falls below the lower limit, the glass transition temperature, the melting point, the vaporization temperature, etc. will decrease. There is a risk that the properties are significantly impaired.
The charge transport material of the present invention usually has a glass transition temperature of 40 ° C. or higher, but is preferably 80 ° C. or higher, and more preferably 110 ° C. or higher, from the viewpoint of heat resistance.
The charge transport material of the present invention usually has a vaporization temperature of 300 ° C. or higher and 800 ° C. or lower.
The charge transport material of the present invention usually has an energy difference between an excited triplet state and a ground state of 2.0 eV or more and 4.0 eV or less, but is excited from the viewpoint of improving the efficiency of an organic electroluminescence device using phosphorescence emission. The energy difference between the triplet state and the ground state is preferably 2.3 eV or more, more preferably 2.6 eV or more, and even more preferably 2.9 eV or more.

As will be described later, the hydrocarbon contained in the charge transport material composition is preferably an aromatic hydrocarbon. Toluene is listed as a representative example of aromatic hydrocarbons, and in the present invention, toluene is used as an index indicating the solubility of an organic compound (charge transport material).
It is preferable that the charge transport material of the present invention has a solubility in toluene of 2.0% by weight or more because a layer constituting the organic electroluminescent element can be easily formed by a wet film forming method. The upper limit of the solubility is not particularly limited, but is usually about 50% by weight.

[Composition for charge transport material]
The composition for a charge transport material of the present invention contains the above-described charge transport material of the present invention, and usually contains the charge transport material of the present invention and a solvent, and more preferably contains a phosphorescent material. Preferably, it is used for organic electroluminescent elements.

[1] Solvent The solvent contained in the composition for a charge transport material of the present invention is not particularly limited as long as it is a solvent that dissolves the charge transport material of the present invention as a solute well.

  Since the charge transport material of the present invention has high solubility, various solvents can be applied. For example, aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and other aromatic ethers; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic esters such as ethyl, propyl benzoate and n-butyl benzoate; ketones having an alicyclic ring such as cyclohexanone and cyclooctanone; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; methyl ethyl ketone and cyclohexano Alcohol having an alicyclic ring such as ruthenium or cyclooctanol; Aliphatic alcohol such as butanol or hexanol; Aliphatic ether such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether or propylene glycol-1-monomethyl ether acetate (PGMEA); Ethyl acetate In addition, aliphatic esters such as n-butyl acetate, ethyl lactate, and n-butyl lactate can be used. Of these, aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene, tetralin and the like are preferable in that they have low water solubility and are not easily altered.

  Since organic electroluminescent devices use many materials such as cathodes that deteriorate significantly due to moisture, the presence of moisture in the composition causes moisture to remain in the dried film, degrading the device characteristics. The possibility is considered and it is not preferable.

  Examples of the method for reducing the amount of water in the composition include nitrogen gas sealing, use of a desiccant, dehydration of the solvent in advance, use of a solvent having low water solubility, and the like. In particular, it is preferable to use a solvent having low water solubility because the solution film can prevent whitening by absorbing moisture in the atmosphere during the wet film-forming process. From such a viewpoint, the composition for a charge transport material to which the present embodiment is applied includes, for example, a solvent having a water solubility at 25 ° C. of 1% by weight or less, preferably 0.1% by weight or less. It is preferable to contain 10% by weight or more in the composition.

  Further, in order to reduce deterioration of film formation stability due to evaporation of the solvent from the composition during wet film formation, the boiling point is 100 ° C. or higher, preferably 150 ° C. as the solvent of the composition for charge transport material. As described above, it is more effective to use a solvent having a boiling point of 200 ° C. or higher. In order to obtain a more uniform film, it is necessary for the solvent to evaporate from the liquid film immediately after film formation at an appropriate rate. For this purpose, the boiling point is usually 80 ° C. or higher, preferably 100 ° C. or higher. It is effective to use a solvent having a boiling point of 120 ° C. or more, usually less than 270 ° C., preferably less than 250 ° C., more preferably less than 230 ° C.

  A solvent that satisfies the above-described conditions, that is, the conditions of solute solubility, evaporation rate, and water solubility may be used alone, or two or more kinds of solvents may be mixed and used.

[2] Luminescent Material The charge transport material composition of the present invention, particularly the charge transport material composition used as the charge transport material composition, preferably contains a luminescent material.

The light emitting material refers to a component that mainly emits light in the composition for a charge transport material of the present invention, and corresponds to a dopant component in an organic electroluminescent device. That is, the amount of light (unit: cd / m ² ) emitted from the composition for charge transport material is usually 10 to 100%, preferably 20 to 100%, more preferably 50 to 100%, most preferably 80 to 100%. If% is identified as luminescence from a component material, it is defined as the luminescent material.

As the light-emitting material, known materials can be applied, and a fluorescent light-emitting material or a phosphorescent light-emitting material can be used alone or in combination, and a phosphorescent light-emitting material is preferable from the viewpoint of internal quantum efficiency.
When used in the composition for a charge transport material of the present invention, the maximum emission peak wavelength of the luminescent material is preferably in the range of 390 to 490 nm.

  For the purpose of improving the solubility in a solvent, it is also important to reduce the symmetry and rigidity of the light emitting material molecule or introduce a lipophilic substituent such as an alkyl group.

  Examples of fluorescent dyes that emit blue light include perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof. Examples of the green fluorescent dye include quinacridone derivatives and coumarin derivatives. Examples of yellow fluorescent dyes include rubrene and perimidone derivatives. Examples of red fluorescent dyes include DCM compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene and the like.

  Examples of the phosphorescent material include organometallic complexes containing a metal selected from Groups 7 to 11 of the periodic table.

Preferred examples of the metal in the phosphorescent organometallic complex containing a metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. Preferred examples of these organometallic complexes include compounds represented by the following general formula (V) or formula (VI).
ML _(q−j) L ′ _j (V)
(In general formula (V), M represents a metal, q represents the valence of the metal, L and L ′ represent a bidentate ligand, and j represents 0, 1 or 2.)

（一般式（VI）中、Ｍ^ｄは金属を表し、Ｔは炭素または窒素を表す。Ｒ^９２〜Ｒ^９５は、それぞれ独立に、置換基を表す。ただし、Ｔが窒素の場合は、Ｒ^９４およびＲ^９５は無い。）

(In the general formula (VI), ^{M d} represents a metal, ^.R 92 ^{to R 95} T is representative of the carbon or nitrogen independently represents a substituent. However, when T is ^{nitrogen, R 94} And there is no R ^95. )

Hereinafter, the compound represented by the general formula (V) will be described first.
In the general formula (V), M represents an arbitrary metal, and specific examples of preferable ones include the metals described above as the metal selected from Groups 7 to 11 of the periodic table.
Moreover, the bidentate ligands L and L ′ in the general formula (V) each represent a ligand having the following partial structure.

As L ′, the followings are particularly preferable from the viewpoint of the stability of the complex.

  In the partial structures of L and L ′, the ring A1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group, and these may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group, and these may have a substituent.

  When the rings A1 and A2 have a substituent, preferred substituents include halogen atoms such as fluorine atoms; alkyl groups such as methyl groups and ethyl groups; alkenyl groups such as vinyl groups; methoxycarbonyl groups and ethoxycarbonyl groups. Alkoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; diarylamino groups such as diphenylamino groups; carbazolyl groups; An acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group; an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, and a phenanthyl group.

  More preferable examples of the compound represented by the general formula (V) include compounds represented by the following general formulas (Va), (Vb), and (Vc).

（一般式（Ｖａ）中、Ｍ^ａはＭと同様の金属を表し、ｗは上記金属の価数を表す。また、環Ａ１は置換基を有していてもよい芳香族炭化水素基を表し、環Ａ２は置換基を有していてもよい含窒素芳香族複素環基を表す。）

(In general formula (Va), M ^a represents the same metal as M, w represents the valence of the metal, and ring A1 represents an aromatic hydrocarbon group which may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

（一般式（Ｖｂ）中、Ｍ^ｂはＭと同様の金属を表し、ｗは上記金属の価数を表す。また、環Ａ１は置換基を有していてもよい芳香族炭化水素基または置換基を有していてもよい芳香族複素環基を表し、環Ａ２は置換基を有していてもよい含窒素芳香族複素環基を表す。）

(In the general formula (Vb), M ^b represents the same metal as M, w represents the valence of the metal. Further, the ring A1 is an aromatic optionally substituted hydrocarbon group or a substituted Represents an aromatic heterocyclic group which may have a group, and ring A2 represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.)

（一般式（Ｖｃ）中、Ｍ^ｃはＭと同様の金属を表し、ｗは上記金属の価数を表す。また、ｊは０、１または２を表す。さらに、環Ａ１および環Ａ１’は、それぞれ独立に、置換基を有していてもよい芳香族炭化水素基または置換基を有していてもよい芳香族複素環基を表す。また、環Ａ２および環Ａ２’は、それぞれ独立に、置換基を有していてもよい含窒素芳香族複素環基を表す。）

(In the general formula (Vc), M ^c represents the same metal as M, w represents the valence of the metal, and j represents 0, 1 or 2. Further, ring A1 and ring A1 ′ represent Each independently represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and ring A2 and ring A2 ′ are each independently Represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.

  In the above general formulas (Va), (Vb), and (Vc), the group of ring A1 and ring A1 ′ is preferably, for example, phenyl group, biphenyl group, naphthyl group, anthryl group, thienyl group, furyl group, benzo Examples include thienyl group, benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group, carbazolyl group and the like.

  In addition, the group of ring A2 and ring A2 ′ is preferably a pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, isoquinolyl group, quinoxalyl group, A phenanthridyl group and the like can be mentioned.

  Furthermore, the substituents that the compounds represented by the general formulas (Va), (Vb), and (Vc) may have include halogen atoms such as fluorine atoms; alkyl groups such as methyl groups and ethyl groups; vinyls Alkenyl groups such as methoxy groups; alkoxycarbonyl groups such as methoxycarbonyl groups and ethoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkyls such as dimethylamino groups and diethylamino groups An amino group; a diarylamino group such as a diphenylamino group; a carbazolyl group; an acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group;

  When the said substituent is an alkyl group, the carbon number is 1 or more and 6 or less normally. Furthermore, when the substituent is an alkenyl group, the carbon number is usually 2 or more and 6 or less. When the substituent is an alkoxycarbonyl group, the carbon number is usually 2 or more and 6 or less. Further, when the substituent is an alkoxy group, the carbon number is usually 1 or more and 6 or less. Moreover, when a substituent is an aryloxy group, the carbon number is 6 or more and 14 or less normally. Furthermore, when the substituent is a dialkylamino group, the carbon number is usually 2 or more and 24 or less. Further, when the substituent is a diarylamino group, the carbon number is usually 12 or more and 28 or less. Furthermore, when the substituent is an acyl group, the carbon number is usually 1 or more and 14 or less. Moreover, when a substituent is a haloalkyl group, the carbon number is 1 or more and 12 or less normally.

  These substituents may be connected to each other to form a ring. As a specific example, a substituent of the ring A1 and a substituent of the ring A2 are bonded, or a substituent of the ring A1 ′ and a substituent of the ring A2 ′ are bonded. Two fused rings may be formed. Examples of such a condensed ring group include a 7,8-benzoquinoline group.

  Among them, as a substituent of ring A1, ring A1 ′, ring A2 and ring A2 ′, more preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group, a cyano group, a halogen atom, a haloalkyl group, a diarylamino group, a carbazolyl group Is mentioned.

In general formula (Va), (Vb), preferably as ^{M a, M b, M c} in (Vc), ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold.

  Specific examples of the organometallic complex represented by the general formula (V), (Va), (Vb) or (Vc) are shown below, but are not limited to the following compounds (in the following, Ph is phenyl Represents a group).

Among the organometallic complexes represented by the general formulas (V), (Va), (Vb), and (Vc), in particular, as the ligand L and / or L ′, a 2-arylpyridine-based ligand, , 2-arylpyridine, a compound having an arbitrary substituent bonded thereto, and a compound having an arbitrary group condensed thereto are preferable.
In addition, compounds described in WO2005 / 019373 can also be used.

Next, the compound represented by the general formula (VI) will be described.
In the general formula (VI), M ^d represents a metal, and specific examples thereof include the metals described above as the metal selected from Groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold is preferable, and divalent metals such as platinum and palladium are particularly preferable.

In the general formula (VI), R ⁹² and R ⁹³ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, or a carboxyl group. Represents an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group.

Further, when T is carbon, R ⁹⁴ and R ⁹⁵ each independently represent a substituent represented by the same examples as R ⁹² and R ⁹³ . Further, as described above, when T is nitrogen, there is no R ⁹⁴ or R ⁹⁵ .

R ^{92 to} R ⁹⁵ may further have a substituent. In this case, the substituent which may further be present is not particularly limited, and any group can be used as the substituent.
Furthermore, R ^{92 to} R ⁹⁵ may be linked to each other to form a ring, and this ring may further have an arbitrary substituent.

  Specific examples (T-1, T-10 to T-15) of the organometallic complex represented by the general formula (VI) are shown below, but are not limited to the following exemplified compounds. In the following, Me represents a methyl group, and Et represents an ethyl group.

[3] Other components In the composition for a charge transport material of the present invention, particularly the composition for a charge transport material used as the composition for a charge transport material, in addition to the solvent and the light emitting material described above, Various other solvents may be included. Examples of such other solvents include amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and dimethyl sulfoxide.
Moreover, various additives, such as a leveling agent and an antifoamer, may be included.

  In addition, when two or more layers are laminated by a wet film-forming method, in order to prevent these layers from being compatible with each other, a photo-curing resin or a thermosetting resin is used for the purpose of curing and insolubilizing after film formation. Can also be contained.

[4] Material concentration and blending ratio in charge transport material composition Charge transport material composition, in particular, charge transport material, light emitting material, and component which can be added as required (leveling agent) in charge transport material composition Etc.) is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, still more preferably 0.5% by weight or more, most preferably 1. It is usually not more than 80% by weight, preferably not more than 50% by weight, more preferably not more than 40% by weight, still more preferably not more than 30% by weight, most preferably not more than 20% by weight. If this concentration is below the lower limit, it is difficult to form a thick film when forming a thin film, and if it exceeds the upper limit, it may be difficult to form a thin film.

  In the charge transport material composition of the present invention, particularly the charge transport material composition, the light emitting material / charge transport material weight mixing ratio is usually 0.1 / 99.9 or more, more preferably 0. 0.5 / 99.5 or more, more preferably 1/99 or more, most preferably 2/98 or more, usually 50/50 or less, more preferably 40/60 or less, still more preferably. Is 30/70 or less, most preferably 20/80 or less. If this ratio falls below the lower limit or exceeds the upper limit, the luminous efficiency may be significantly reduced.

[5] Method for Preparing Charge Transport Material Composition The charge transport material composition of the present invention, particularly the charge transport material composition, comprises a charge transport material, a light-emitting material, and a leveling agent or an extinction agent that can be added as necessary. It is prepared by dissolving a solute composed of various additives such as a foaming agent in an appropriate solvent. In order to shorten the time required for the dissolution step and to keep the solute concentration in the composition uniform, the solute is usually dissolved while stirring the liquid. The dissolution step may be performed at room temperature, but when the dissolution rate is slow, it can be heated and dissolved. After completion of the dissolution step, a filtration step such as filtering may be performed as necessary.

[6] Properties, physical properties, etc. (moisture concentration) of the composition for charge transport materials
When an organic electroluminescent device is produced by forming a layer by a wet film forming method using the composition for charge transport material of the present invention (composition for charge transport material), moisture is present in the composition for charge transport material to be used. Then, since moisture is mixed into the formed film and the uniformity of the film is impaired, it is preferable that the water content in the charge transport material composition of the present invention, particularly the charge transport material composition, is as low as possible. In general, since organic electroluminescent devices use many materials such as cathodes that deteriorate significantly due to moisture, when moisture is present in the composition for charge transport material, moisture remains in the dried film. The possibility of deteriorating the characteristics of the element is considered, which is not preferable.

  Specifically, the amount of water contained in the composition for a charge transport material of the present invention, particularly the composition for a charge transport material, is usually 1% by weight or less, preferably 0.1% by weight or less, more preferably 0.8%. 01% by weight or less.

  As a method for measuring the water concentration in the composition for charge transport material, the method described in Japanese Industrial Standard “Method for Measuring Water of Chemical Products” (JIS K0068: 2001) is preferable. For example, Karl Fischer reagent method (JIS K0211- 1348) and the like.

(Uniformity)
The charge transport material composition of the present invention, particularly the charge transport material composition, is uniform at room temperature in order to improve stability in a wet film forming process, for example, ejection stability from a nozzle in an ink jet film forming method. It is preferably a liquid. The uniform liquid at normal temperature means that the composition is a liquid composed of a uniform phase and does not contain a particle component having a particle size of 0.1 μm or more in the composition.

(Physical properties)
Regarding the viscosity of the charge transport material composition of the present invention, particularly the charge transport material composition, in the case of extremely low viscosity, for example, uneven coating surface due to excessive liquid film flow in the film forming process, Nozzle discharge failure or the like is likely to occur, and when the viscosity is extremely high, nozzle clogging or the like in the ink-jet film formation is likely to occur. For this reason, the viscosity at 25 ° C. of the composition of the present invention is usually 2 mPa · s or more, preferably 3 mPa · s or more, more preferably 5 mPa · s or more, and usually 1000 mPa · s or less, preferably 100 mPa · s or less. More preferably, it is 50 mPa · s or less.

  In addition, when the surface tension of the composition for charge transport material of the present invention, particularly the composition for charge transport material is high, the wettability of the film-forming liquid to the substrate is lowered, the leveling property of the liquid film is poor, and the Therefore, the surface tension at 20 ° C. of the composition of the present invention is usually less than 50 mN / m, preferably less than 40 mN / m.

  Furthermore, when the vapor pressure of the composition for a charge transport material of the present invention, particularly the composition for a charge transport material is high, problems such as a change in solute concentration due to evaporation of the solvent may easily occur. For this reason, the vapor pressure at 25 ° C. of the composition of the present invention is usually 50 mmHg or less, preferably 10 mmHg or less, more preferably 1 mmHg or less.

[7] Method for Preserving Composition for Charge Transport Material The composition for a charge transport material of the present invention is preferably filled in a container capable of preventing the transmission of ultraviolet rays, such as a brown glass bottle, and stored tightly. . The storage temperature is usually −30 ° C. or higher, preferably 0 ° C. or higher, and usually 35 ° C. or lower, preferably 25 ° C. or lower.

[Organic electroluminescence device]
The organic electroluminescent element of the present invention has an anode, a cathode, and a light emitting layer provided between both electrodes on a substrate, and has a layer containing the charge transport material of the present invention. . The layer containing the charge transport material is preferably formed using the charge transport material composition of the present invention. The layer containing the charge transport material is preferably the light emitting layer. In addition, the layer containing the charge transport material is preferably doped with an organometallic complex. As this organometallic complex, those exemplified as the light emitting material can be used.

  1 to 8 are schematic sectional views showing structural examples suitable for the organic electroluminescence device of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a light emitting layer, 5 represents an electron injection layer, and 6 represents a cathode.

[1] Substrate The substrate 1 serves as a support for the organic electroluminescent element, and quartz or glass plates, metal plates, metal foils, plastic films, sheets, and the like are used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

[2] Anode An anode 2 is provided on the substrate 1. The anode 2 plays a role of hole injection into a layer on the light emitting layer side (such as the hole injection layer 3 or the light emitting layer 4).

  This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or A conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline is used.

  In general, the anode 2 is often formed by sputtering, vacuum deposition, or the like. In addition, when forming an anode using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, or conductive polymer fine powder, an appropriate binder resin solution is used. The anode 2 can also be formed by dispersing and coating the substrate 1. Further, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

  The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

  The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.

[3] Hole Injection Layer Since the hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 4, the hole injection layer 3 preferably contains a hole transporting compound.

  In the hole injection layer 3, a cation radical obtained by removing one electron from an electrically neutral compound accepts one electron from a nearby electrically neutral compound, whereby holes move. When the cation radical compound is not included in the hole injection layer 3 when the element is not energized, the cation radical of the hole transport compound is generated when the hole transport compound gives electrons to the anode 2 during energization, Holes are transported by transferring electrons between the cation radical and an electrically neutral hole transporting compound.

  When the hole injection layer 3 contains a cation radical compound, cation radicals necessary for hole transport are present at a concentration higher than that generated by oxidation by the anode 2, and the hole transport performance is improved. It is preferable that the hole injection layer 3 contains a cation radical compound. When an electrically neutral hole transporting compound is present in the vicinity of the cation radical compound, electrons are transferred smoothly, so that the hole injection layer 3 contains a cation radical compound and a hole transporting compound. Is more preferable.

  Here, the cation radical compound is a cation radical that is a chemical species obtained by removing one electron from a hole transporting compound, and an ionic compound composed of a counter anion, and already has holes (free carriers) that are easy to move. Yes.

  Further, by mixing an electron-accepting compound with the hole-transporting compound, one-electron transfer from the hole-transporting compound to the electron-accepting compound occurs, and the above-described cation radical compound is generated. For this reason, it is preferable that the hole injection layer 3 contains a hole transporting compound and an electron accepting compound.

  Summarizing the above preferred materials, the hole injection layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. The hole injection layer 3 preferably contains a cation radical compound, and more preferably contains a cation radical compound and a hole transporting compound.

  Furthermore, the hole injection layer 3 may contain a binder resin that does not easily trap charges and a coating property improving agent as necessary.

  However, as the hole injection layer 3, the electron accepting compound alone or the electron accepting compound and the hole transporting compound are used to form a film on the anode 2 by a wet film forming method, and the direct injection of the present invention is performed directly from above. It is also possible to laminate the charge transport material composition by coating or vapor deposition. In this case, part or all of the charge transport material composition of the present invention interacts with the electron-accepting compound, so that the hole transport layer 10 having excellent hole injecting property is obtained as shown in FIGS. It is formed.

(Hole transporting compound)
As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable.

  Examples of the hole transporting compound include an aromatic amine compound, a phthalocyanine derivative, a porphyrin derivative, an oligothiophene derivative, a polythiophene derivative and the like in addition to the charge transport material of the present invention. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness and visible light transmittance.

  Among the aromatic amine compounds, aromatic tertiary amine compounds such as the charge transport material of the present invention are particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.

  The type of the aromatic tertiary amine compound is not particularly limited, but a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less (a polymerization organic compound in which repeating units are linked) is more preferable from the viewpoint of the surface smoothing effect.

  Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following general formula (VII).

（一般式（VII）中、Ａｒ^２１，Ａｒ^２２は各々独立して、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。Ａｒ^２３〜Ａｒ^２５は、各々独立して、置換基を有していてもよい２価の芳香族炭化水素基、または置換基を有していてもよい２価の芳香族複素環基を表す。Ｙは、下記の連結基群の中から選ばれる連結基を表す。また、Ａｒ^２１〜Ａｒ^２５のうち、同一のＮ原子に結合する二つの基は互いに結合して環を形成してもよい。）

(In the general formula (VII), Ar ²¹ and Ar ²² each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ^{23 to} Ar ²⁵ each independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent. Y represents a linking group selected from the following group of linking groups, and among Ar ^{21 to} Ar ²⁵ , two groups bonded to the same N atom are bonded to each other to form a ring. May be.)

（上記各式中、Ａｒ^３１〜Ａｒ^４１は、各々独立して、置換基を有していてもよい芳香族炭化水素環、または置換基を有していてもよい芳香族複素環由来の１価または２価の基を表す。Ｒ^１０１およびＲ^１０２は、各々独立して、水素原子または任意の置換基を表す。））

(In the above formulas, Ar ^{31 to} Ar ⁴¹ are each independently 1 derived from an aromatic hydrocarbon ring which may have a substituent, or an aromatic heterocyclic ring which may have a substituent. And R ¹⁰¹ and R ¹⁰² each independently represents a hydrogen atom or an optional substituent.)

As Ar ^{21 to} Ar ²⁵ and Ar ^{31 to} Ar ⁴¹ , any monovalent or divalent group derived from any aromatic hydrocarbon ring or aromatic heterocyclic ring is applicable. These may be the same or different from each other. Moreover, you may have arbitrary substituents.

  Examples of the aromatic hydrocarbon ring include a 5- or 6-membered monocyclic ring or a 2-5 condensed ring. Specific examples include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring and the like.

  The aromatic heterocycle includes a 5- or 6-membered monocyclic ring or a 2-4 condensed ring. Specific examples include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Synoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

Moreover, as Ar < ²³ > -Ar < ²⁵ >, Ar < ³¹ > -Ar < ³⁵ >, Ar < ³⁷ > -Ar < ⁴⁰ >, the bivalent origin derived from the 1 type or 2 types or more of aromatic hydrocarbon ring and / or aromatic heterocycle which were illustrated above is shown. Two or more groups may be linked and used.

The group derived from the aromatic hydrocarbon ring and / or aromatic heterocycle of Ar ^{21 to} Ar ⁴¹ may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. The type of the substituent is not particularly limited, and examples thereof include one or more selected from the following substituent group D.

[Substituent group D]
An alkyl group having usually 1 or more, usually 10 or less, preferably 8 or less, such as a methyl group or an ethyl group; an alkenyl group having 2 or more, usually 11 or less, preferably 5 or less carbon atoms, such as a vinyl group. An alkynyl group having usually 2 or more, usually 11 or less, preferably 5 or less, such as an ethynyl group; an alkoxy having a carbon number of usually 1 or more, usually 10 or less, preferably 6 or less, such as a methoxy group or an ethoxy group; A group; an aryloxy group such as a phenoxy group, a naphthoxy group, a pyridyloxy group, etc., usually 4 or more, preferably 5 or more, usually 25 or less, preferably 14 or less; a carbon such as a methoxycarbonyl group or an ethoxycarbonyl group An alkoxycarbonyl group having a number of usually 2 or more, usually 11 or less, preferably 7 or less; a dimethylamino group, a diethylamino group or the like, and usually having 2 or more carbon atoms Usually 20 or less, preferably 12 or less dialkylamino group; diphenylamino group, ditolylamino group, N-carbazolyl group, etc., and usually diarylamino having 10 or more carbon atoms, preferably 12 or more, usually 30 or less, preferably 22 or less Group: an arylalkylamino group having 6 or more carbon atoms, preferably 7 or more, usually 25 or less, preferably 17 or less, such as a phenylmethylamino group; an acetyl group, a benzoyl group or the like, and usually having 2 or more carbon atoms, Usually an acyl group of 10 or less, preferably 7 or less; a halogen atom such as a fluorine atom or a chlorine atom; a haloalkyl group having a carbon number of usually 1 or more, usually 8 or less, preferably 4 or less, such as a trifluoromethyl group; An alkylthio group having 1 to 10 carbon atoms, preferably 6 or less, preferably 6 or less; An arylthio group having a carbon number of usually 4 or more, preferably 5 or more, usually 25 or less, preferably 14 or less, such as a ruthio group, a naphthylthio group, or a pyridylthio group; Or more, preferably 3 or more, usually 33 or less, preferably 26 or less silyl group; trimethylsiloxy group, triphenylsiloxy group, etc., the carbon number is usually 2 or more, preferably 3 or more, usually 33 or less, preferably 26 or less. A siloxy group; a cyano group; an aromatic hydrocarbon ring group having usually 6 or more, usually 30 or less, preferably 18 or less, such as a phenyl group or a naphthyl group; a carbon number such as a thienyl group or a pyridyl group. An aromatic heterocyclic group of 3 or more, preferably 4 or more, usually 28 or less, preferably 17 or less.

Ar ²¹ and Ar ²² are preferably monovalent groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring from the viewpoint of the solubility, heat resistance, and hole injection / transport properties of the polymer compound. More preferred are a phenyl group and a naphthyl group.

Ar ^{23 to} Ar ²⁵ are preferably divalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring from the viewpoint of heat resistance and hole injection / transport properties including redox potential. More preferably a group, a biphenylene group, or a naphthylene group.

As R ¹⁰¹ and R ¹⁰² , a hydrogen atom or an arbitrary substituent is applicable. These may be the same or different from each other. The type of the substituent is not particularly limited, and examples of applicable substituents include alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, silyl groups, siloxy groups, aromatic hydrocarbon groups, aromatic heterocyclic rings. Group and halogen atom. Specific examples thereof include the groups exemplified in the above substituent group D.

  Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the general formula (VII) include those described in WO2005 / 089024, and preferred examples thereof are also the same. Although the compound (PB-1) represented by Structural Formula is mentioned, it is not limited to them at all.

  Preferable examples of the other aromatic tertiary amine polymer compounds include polymer compounds containing a repeating unit represented by the following general formula (VIII) and / or general formula (IX).

（一般式（VIII）、（IX）中、Ａｒ^４５，Ａｒ^４７およびＡｒ^４８は各々独立して、置換基を有していてもよい芳香族炭化水素基、または置換基を有していてもよい芳香族複素環基を表す。Ａｒ^４４およびＡｒ^４６は各々独立して、置換基を有していてもよい２価の芳香族炭化水素基、または置換基を有していてもよい２価の芳香族複素環基を表す。また、Ａｒ^４５〜Ａｒ^４８のうち、同一のＮ原子に結合する２つの基は互いに結合して環を形成してもよい。Ｒ^１１１〜Ｒ^１１３は各々独立して、水素原子または任意の置換基を表す。）

(In the general formulas (VIII) and (IX), Ar ⁴⁵ , Ar ⁴⁷ and Ar ⁴⁸ may each independently have an aromatic hydrocarbon group which may have a substituent, or a substituent. And each of Ar ⁴⁴ and Ar ⁴⁶ independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent which may have a substituent. In addition, two groups bonded to the same N atom among Ar ^{45 to} Ar ⁴⁸ may be bonded to each other to form a ring, and R ^{111 to} R ¹¹³ are each independently And represents a hydrogen atom or an arbitrary substituent.)

Specific examples of Ar ⁴⁵ , Ar ⁴⁷ , Ar ⁴⁸ and Ar ⁴⁴ , Ar ⁴⁶ , preferred examples, examples of substituents that may be included and examples of preferred substituents are Ar ²¹ , Ar ^22, and Ar ²³ ˜ Same as Ar ²⁵ . R ^{111 to} R ¹¹³ are preferably a hydrogen atom or a substituent described in [Substituent group D], more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, It is an aromatic hydrocarbon group.

  Specific examples of the aromatic tertiary amine polymer compound containing a repeating unit represented by the general formula (VIII) and / or (IX) include those described in WO2005 / 089024, and preferred examples thereof are also included. Although it is the same, it is not limited to them at all.

  Moreover, when forming a positive hole injection layer with a wet film forming method, the positive hole transport compound which is easy to melt | dissolve in a various solvent is preferable. As the aromatic tertiary amine compound, for example, a binaphthyl compound (Japanese Patent Laid-Open No. 2004-014187) and an asymmetric 1,4-phenylenediamine compound (Japanese Patent Laid-Open No. 2004-026732) are preferable.

  In addition, compounds that are easily soluble in various solvents may be appropriately selected from aromatic amine compounds that have been conventionally used as a hole injection / transport thin film purification material in organic electroluminescent devices. Examples of the aromatic amine compound applicable to the hole-transporting compound of the hole-injecting layer include conventionally known compounds that have been utilized as a hole-injecting / transporting layer-forming material in organic electroluminescence devices. It is done. For example, an aromatic diamine compound in which a tertiary aromatic amine unit such as 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane is linked (JP 59-194393 A); 4,4′- An aromatic amine compound containing two or more tertiary amines represented by bis [N- (1-naphthyl) -N-phenylamino] biphenyl and having two or more condensed aromatic rings substituted with nitrogen atoms No. 5-23481); an aromatic triamine compound having a starburst structure as a derivative of triphenylbenzene (US Pat. No. 4,923,774); N, N′-diphenyl-N, N′-bis (3- Aromatic diamine compounds such as methylphenyl) biphenyl-4,4′-diamine (US Pat. No. 4,764,625); α, α, α ′, α′-tetramethyl-α, α′- Bis (4-di (p-tolyl) aminophenyl) -p-xylene (Japanese Patent Laid-Open No. 3-269084); sterically asymmetric triphenylamine derivative as a whole molecule (Japanese Patent Laid-Open No. 4-129271); pyrenyl A compound in which a plurality of aromatic diamino groups are substituted on the group (Japanese Patent Laid-Open No. 4-175395); an aromatic diamine compound in which a tertiary aromatic amine unit is linked with an ethylene group (Japanese Patent Laid-Open No. 4-264189); a styryl structure An aromatic diamine having a thiophene group (JP-A-4-290851); a compound in which an aromatic tertiary amine unit is linked by a thiophene group (JP-A-4-304466); a starburst type aromatic triamine compound (JP-A-4-30481) 308688); benzylphenyl compound (Japanese Patent Laid-Open No. 4-364153); Compounds in which thiones are linked (JP-A-5-25473); triamine compounds (JP-A-5-239455); bisdipyridylaminobiphenyl (JP-A-5-320634); N, N, N-triphenylamine Derivatives (JP-A-6-1972); Aromatic diamines having a phenoxazine structure (JP-A-7-138562); Diaminophenylphenanthridine derivatives (JP-A-7-252474); 2-311591); silazane compounds (US Pat. No. 4,950,950); silanamine derivatives (JP-A-6-49079); phosphamine derivatives (JP-A-6-25659); quinacridone compounds, etc. Can be mentioned. These aromatic amine compounds may be used in combination of two or more as required.

  Preferred specific examples of the phthalocyanine derivative or porphyrin derivative applicable to the hole transporting compound of the hole injection layer include porphyrin, 5,10,15,20-tetraphenyl-21H, 23H-porphyrin, 5,10 , 15,20-tetraphenyl-21H, 23H-porphyrin cobalt (II), 5,10,15,20-tetraphenyl-21H, 23H-porphyrin copper (II), 5,10,15,20-tetraphenyl- 21H, 23H-porphyrin zinc (II), 5,10,15,20-tetraphenyl-21H, 23H-porphyrin vanadium (IV) oxide, 5,10,15,20-tetra (4-pyridyl) -21H, 23H -Porphyrin, 29H, 31H-phthalocyanine copper (II), phthalocyanine zinc (II), Russia Nin titanium, phthalocyanine oxide magnesium, phthalocyanine lead, phthalocyanine copper (II), 4,4 ', 4 ", 4' '' - tetraaza-29H, 31H-phthalocyanine, and the like.

  Further, preferred specific examples of the oligothiophene derivative applicable as the hole transporting compound of the hole injection layer include α-terthiophene and its derivatives, α-sexithiophene and its derivatives, and oligothiophene containing a naphthalene ring. Derivatives (JP-A-6-256341) and the like.

  Further, preferred specific examples of the polythiophene derivative applicable as the hole transporting compound in the present invention include poly (3,4-ethylenedioxythiophene) (PEDOT), poly (3-hexylthiophene) and the like.

  The molecular weight of these hole transporting compounds is usually 9000 or less, preferably 5000 or less, and usually 200 or more, preferably 400 or more, except in the case of a polymer compound (a polymerizable compound in which repeating units are continuous). Range. If the molecular weight of the hole transporting compound is too high, synthesis and purification are difficult, which is not preferable. On the other hand, if the molecular weight is too low, the heat resistance may be lowered, which is also not preferable.

  The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. When two or more hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or two other hole transporting compounds are used. It is preferable to use the above together.

(Electron-accepting compound)
The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is more preferable.

  Examples include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, iron (III) chloride (JP-A-11-251067), ammonium peroxodisulfate and the like. Examples thereof include valent inorganic compounds, cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365), fullerene derivatives, iodine and the like.

  Of the above compounds, onium salts substituted with organic groups and high valent inorganic compounds are preferred because of their strong oxidizing power, and organic groups are substituted because they are soluble in various solvents and applicable to wet coating. Preferred are onium salts, cyano compounds, and aromatic boron compounds.

  Specific examples of an onium salt substituted with an organic group, a cyano compound, and an aromatic boron compound suitable as an electron-accepting compound include those described in WO 2005/089024, and suitable examples thereof are also the same. Although the compound (A-2) represented by the following structural formula is mentioned, it is not limited to them at all.

(Cation radical compound)
The cation radical compound is an ionic compound composed of a cation radical which is a chemical species obtained by removing one electron from a hole transporting compound and a counter anion. However, when the cation radical is derived from a hole transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

  The cation radical is preferably a chemical species obtained by removing one electron from the aforementioned compound in the hole transporting compound, and is preferably a chemical species obtained by removing one electron from a compound more preferable as the hole transporting compound. From the viewpoints of visible light transmittance, heat resistance, solubility, and the like.

  The cation radical compound can be generated by mixing the hole transporting compound and the electron accepting compound. That is, by mixing the hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the cation radical and the counter anion of the hole transporting compound are included. A cation ion compound is formed.

  Cationic radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, 12, 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, 94, 7716) It is also generated by oxidative polymerization (dehydrogenation polymerization), that is, by oxidizing a monomer chemically or electrochemically with peroxodisulfate in an acidic solution. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is oxidized to be polymerized, and the cation radical is formed by removing one electron from the repeating unit of the polymer with an anion derived from an acidic solution as a counter anion. Produces.

  The hole injection layer 3 is formed on the anode 2 by a wet film forming method or a vacuum deposition method.

  ITO (indium tin oxide), which is generally used as the anode 2, has a surface roughness of about 10 nm (Ra) and, in addition, often has protrusions locally, resulting in short-circuit defects. There was a problem that it was easy to produce. When the hole injection layer 3 formed on the anode 2 is formed by the wet film forming method, the generation of device defects due to the unevenness of the surface of the anode as compared with the case of forming by the vacuum deposition method. Has the advantage of reducing.

  In the case of layer formation by the wet film-forming method, a predetermined amount of one or more of the aforementioned materials (hole transporting compound, electron accepting compound, cation radical compound) does not become a charge trap if necessary. Add binder resin and coatability improver, dissolve in solvent, prepare coating solution, by wet film forming method such as spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, inkjet method etc. It is applied on the anode and dried to form the hole injection layer 3.

  As the solvent used for the layer formation by the wet film forming method, any solvent can be used as long as it can dissolve the above-mentioned materials (hole transporting compound, electron accepting compound, cation radical compound). Is not particularly limited, but generates a deactivated substance or deactivated substance that may deactivate each material (hole transporting compound, electron accepting compound, cation radical compound) used in the hole injection layer The thing which does not contain is preferable.

  Preferred solvents that satisfy these conditions include, for example, ether solvents and ester solvents. Specifically, examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1, 3 -Aromatic ethers such as dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and the like. Examples of the ester solvent include aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and benzoic acid. Examples include aromatic esters such as n-butyl. Any one of these may be used alone, or two or more thereof may be used in any combination and ratio.

  Examples of solvents that can be used in addition to the ether solvents and ester solvents described above include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and amides such as N, N-dimethylformamide and N, N-dimethylacetamide. System solvents, dimethyl sulfoxide and the like. Any one of these may be used alone, or two or more thereof may be used in any combination and ratio. Moreover, you may use 1 type (s) or 2 or more types among these solvents in combination with 1 type (s) or 2 or more types among the above-mentioned ether solvent and ester solvent. In particular, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve electron accepting compounds and cation radical compounds, and therefore are preferably mixed with ether solvents and ester solvents.

  The concentration of the solvent in the coating solution is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 99.999% by weight or less, preferably 99.99% by weight or less. Preferably it is the range of 99.9 weight% or less. When two or more kinds of solvents are mixed and used, the total of these solvents is set to satisfy this range.

In the case of forming a layer by vacuum deposition, one or more of the aforementioned materials (hole transporting compound, electron accepting compound, cation radical compound) are put in a crucible installed in a vacuum vessel ( When two or more materials are used, put them in each crucible), and after evacuating the inside of the vacuum vessel to about 10 ⁻⁴ Pa with an appropriate vacuum pump, heat the crucible (if using two or more materials, each Heat the crucible) and evaporate by controlling the amount of evaporation (if more than one material is used, evaporate by controlling the amount of evaporation independently) and place it positively on the anode of the substrate placed facing the crucible A hole injection layer is formed. In addition, when using 2 or more types of materials, they can also be put into a crucible, can be heated and evaporated, and can be used for hole injection layer formation.

The film thickness of the hole injection layer 3 that may be formed in this manner is usually in the range of 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
The hole injection layer 3 may be omitted as shown in FIG.

[4] Light-Emitting Layer A normal light-emitting layer 4 is provided on the hole injection layer 3. The light emitting layer 4 is a layer containing a light emitting material, and between the electrodes to which an electric field is applied, holes injected from the anode 2 through the hole injection layer 3 and electrons injected from the cathode 6 through the electron transport layer 5 It is a layer that is excited by recombination and becomes a main light emitting source. The light-emitting layer 4 preferably contains a light-emitting material (dopant) and one or more host materials, and the light-emitting layer 4 more preferably contains the charge transport material of the present invention as a host material, and is formed by a vacuum deposition method. However, it is particularly preferable that the layer be prepared by a wet film-forming method using the composition for charge transport material of the present invention.

  Here, the wet film-forming method is a film formed by applying the composition for a charge transport material of the present invention containing the above-mentioned solvent by spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, or inkjet method. To do.

  In addition, the light emitting layer 4 may contain other materials and components as long as the performance of the present invention is not impaired.

  In general, when the same material is used in the organic electroluminescent element, the thinner the film thickness between the electrodes, the larger the effective electric field, so that the injected current increases, so the driving voltage decreases. For this reason, the driving voltage of the organic electroluminescence device decreases when the total film thickness between the electrodes is thin, but if it is too thin, a short circuit occurs due to the protrusion caused by the electrode such as ITO. Necessary.

  In the present invention, in addition to the light emitting layer 4, when the organic layer such as the hole injection layer 3 and the electron transport layer 5 described later is provided, the light emitting layer 4 and other organic materials such as the hole injection layer 3 and the electron transport layer 5 are used. The total film thickness combined with the layer is usually 30 nm or more, preferably 50 nm or more, more preferably 100 nm or more, usually 1000 nm or less, preferably 500 nm or less, more preferably 300 nm or less. In addition, when the conductivity of the hole injection layer 3 other than the light emitting layer 4 and the electron injection layer 5 described later is high, the amount of charge injected into the light emitting layer 4 increases. It is also possible to reduce the drive voltage while increasing the thickness to reduce the thickness of the light emitting layer 4 and maintaining the total thickness to some extent.

  Therefore, the thickness of the light emitting layer 4 is usually 10 nm or more, preferably 20 nm or more, and usually 300 nm or less, preferably 200 nm or less. When the element of the present invention has only the light emitting layer 4 between the anode and the cathode, the thickness of the light emitting layer 4 is usually 30 nm or more, preferably 50 nm or more, usually 500 nm or less, preferably 300 nm or less. is there.

[5] Electron Injection Layer The electron injection layer 5 plays a role of efficiently injecting electrons injected from the cathode 6 into the light emitting layer 4. In order to perform electron injection efficiently, the material for forming the electron injection layer 5 is preferably a metal having a low work function, and alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium are used.
The film thickness of the electron injection layer 5 is preferably 0.1 to 5 nm.

Alternatively, an ultrathin insulating film (0.1 to 5 nm) such as LiF, MgF ₂ , Li ₂ O, or CsCO ₃ may be inserted at the interface between the cathode 6 and the light emitting layer 4 or the electron transport layer 8 described later. (Appl. Phys. Lett., 70, 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, 44, 1245, 1997); SID 04 Digest, page 154).

  Further, organic electron transport materials represented by metal complexes such as nitrogen-containing heterocyclic compounds such as bathophenanthroline and aluminum complexes of 8-hydroxyquinoline described later are doped with alkali metals such as sodium, potassium, cesium, lithium and rubidium. (Described in JP-A-10-270171, JP-A 2002-1000047, JP-A 2002-1000048, and the like) makes it possible to improve electron injection / transport properties and achieve excellent film quality. Therefore, it is preferable. The film thickness in this case is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 5 is formed by laminating on the light emitting layer 4 by a wet film forming method or a vacuum deposition method in the same manner as the light emitting layer 4. In the case of the vacuum evaporation method, the evaporation source is put into a crucible or metal boat installed in a vacuum vessel, and the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with an appropriate vacuum pump, and then the crucible or metal boat is Heat and evaporate to form an electron injection layer on the substrate placed facing the crucible or metal boat.

The alkali metal is deposited using an alkali metal dispenser in which nichrome is filled with an alkali metal chromate and a reducing agent. By heating the dispenser in a vacuum container, the alkali metal chromate is reduced and the alkali metal is evaporated. In the case of co-evaporating the organic electron transport material and the alkali metal, the organic electron transport material is put in a crucible installed in a vacuum vessel, and the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with a suitable vacuum pump. Each crucible and dispenser are heated simultaneously to evaporate to form an electron injection layer on the substrate placed facing the crucible and dispenser.

At this time, co-evaporation is uniformly performed in the film thickness direction of the electron injection layer 5, but there may be a concentration distribution in the film thickness direction.
The electron injection layer 5 may be omitted as shown in FIGS.

[6] Cathode The cathode 6 plays a role of injecting electrons into a layer on the light emitting layer side (such as the electron injection layer 5 or the light emitting layer 4). The material used for the cathode 6 can be the material used for the anode 2, but a metal having a low work function is preferable for efficient electron injection, such as tin, magnesium, indium, calcium, A suitable metal such as aluminum or silver or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

  The film thickness of the cathode 6 is usually the same as that of the anode 2. For the purpose of protecting the cathode made of a low work function metal, further laminating a metal layer having a high work function and stable to the atmosphere on the cathode increases the stability of the device. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum are used.

[7] Other Constituent Layers While the description has been given centering on the element having the layer constitution shown in FIG. 1, the performance between the anode 2 and the cathode 6 and the light emitting layer 4 in the organic electroluminescent element of the present invention is described. In addition to the layers described above, any layer may be included, and any layer other than the light emitting layer 4 may be omitted.

  Examples of the layer that may be included include the electron transport layer 7. The electron transport layer 7 is provided between the light emitting layer 4 and the electron injection layer 5 as shown in FIG. 2 for the purpose of further improving the light emission efficiency of the device.

The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 6 between electrodes to which an electric field is applied in the direction of the light emitting layer 4. As an electron transport compound used for the electron transport layer 7, the electron injection efficiency from the cathode 6 or the electron injection layer 5 is high, and the injected electrons can be efficiently transported with high electron mobility. It must be a compound.
Materials satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives, Styryl biphenyl derivative, silole derivative, 3- or 5-hydroxyflavone metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compound No. 207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide, n-type sulfide Examples include zinc and n-type zinc selenide.

  The lower limit of the thickness of the electron transport layer 7 is usually 1 nm, preferably about 5 nm, and the upper limit is usually about 300 nm, preferably about 100 nm.

  The electron transport layer 7 is formed by laminating on the light emitting layer 4 by a wet film forming method or a vacuum deposition method in the same manner as the hole injection layer 3. Usually, a vacuum deposition method is used.

  Moreover, it is preferable in this invention to have the positive hole transport layer 10, and it is preferable that the positive hole transport layer 10 contains the charge transport material of this invention. Moreover, the compound illustrated as a hole transportable compound of the said positive hole injection layer can also be used. Alternatively, a polymer material such as polyarylene ether sulfone containing polyvinyl carbazole, polyvinyl triphenylamine, or tetraphenylbenzidine may be used. The hole transport layer 10 is formed by laminating these materials on the hole injection layer by a wet film formation method or a vacuum deposition method. The film thickness of the hole transport layer 10 thus formed is usually 10 nm or more, preferably 30 nm. However, it is usually 300 nm or less, preferably 100 nm or less.

  In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting substance, it is also effective to provide the hole blocking layer 8 as shown in FIG. The hole blocking layer 8 has a function of confining holes and electrons in the light emitting layer 4 and improving luminous efficiency. That is, the hole blocking layer 8 is generated by blocking the holes moving from the light emitting layer 4 from reaching the electron transport layer 7, thereby increasing the recombination probability with electrons in the light emitting layer 4. There is a role of confining excitons in the light emitting layer 4 and a role of efficiently transporting electrons injected from the electron transport layer 8 toward the light emitting layer 4.

  The hole blocking layer 8 prevents the holes moving from the anode 2 from reaching the cathode 6 and can efficiently transport the electrons injected from the cathode 6 toward the light emitting layer 4. The compound is laminated on the light emitting layer 4 so as to be in contact with the interface of the light emitting layer 4 on the cathode 6 side.

  The physical properties required for the material constituting the hole blocking layer 8 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high.

  Examples of the hole blocking layer material satisfying such conditions include mixed arrangements of bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Ligand complexes, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives ( JP-A-11-242996), triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7-41759) And phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297).

  Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in WO2005 / 022962 is also preferable as the hole blocking material.

  The film thickness of the hole blocking layer 8 is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

  The hole blocking layer 8 can also be formed by the same method as the hole injection layer 3, but a vacuum deposition method is usually used.

  The electron transport layer 7 and the hole blocking layer 8 may be appropriately provided as necessary. 1) Only the electron transport layer, 2) Only the hole blocking layer, 3) Lamination of the hole blocking layer / electron transport layer, 4) There are usages such as not using. Further, as shown in FIG. 7, the electron injection layer 5 may be omitted and the hole blocking layer 8 and the electron transport layer 7 may be laminated, or only the electron transport layer 7 may be formed as shown in FIG.

  For the same purpose as the hole blocking layer 8, it is also effective to provide an electron blocking layer 9 between the hole injection layer 3 and the light emitting layer 4 as shown in FIG. The electron blocking layer 9 increases the probability of recombination with holes in the light emitting layer 4 by blocking the electrons moving from the light emitting layer 4 from reaching the hole injection layer 3, thereby generating excitons generated. Has a role of confining the light in the light emitting layer 4 and a role of efficiently transporting holes injected from the hole injection layer 3 in the direction of the light emitting layer 4.

  The characteristics required for the electron blocking layer 9 include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Further, when the light emitting layer 4 is formed by a wet film forming method, it is preferable that the electron blocking layer 9 is also formed by a wet film forming method because the device manufacturing becomes easy.

  For this reason, it is preferable that the electron blocking layer 9 also has wet film forming compatibility. As a material used for such an electron blocking layer 9, a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB is used. (Described in WO 2004/084260).

  The structure opposite to that shown in FIG. 1, that is, the cathode 6, the electron injection layer 5, the light emitting layer 4, the hole injection layer 3, and the anode 2 can be laminated on the substrate 1 in this order. It is also possible to provide the organic electroluminescent element of the present invention between two substrates, at least one of which is highly transparent. Similarly, it is also possible to laminate in a structure opposite to the above-described respective layer configurations shown in FIGS.

Further, a structure in which a plurality of layers shown in FIG. 1 are stacked (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interfacial layer (between the light emitting units) (when the anode is ITO and the cathode is Al, the two layers), for example, V ₂ O ₅ is used as the charge generation layer (CGL). This is more preferable from the viewpoint of luminous efficiency and driving voltage.

  The present invention can be applied to any of an organic electroluminescent element having a single element, an element having a structure arranged in an array, and a structure having an anode and a cathode arranged in an XY matrix.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

[Synthesis Example of Organic Compound of the Present Invention]
Examples of synthesizing the organic compound of the present invention are shown below.
In the following examples, the glass transition temperature was determined by DSC measurement, the vaporization temperature was determined by TG-DTA measurement, and the melting point was determined by DSC measurement or TG-DTA measurement.

(Example 1: objects 1 and 2)

  In a nitrogen stream, carbazole (12.7 g), p-diiodobenzene (25.0 g), copper powder (4.82 g), potassium carbonate (21.0 g), and tetraglyme (45 ml) were heated to 145 ° C. The mixture was stirred for 5 hours and allowed to cool to room temperature. Chloroform was added to the reaction mixture, and insoluble matters were filtered off. Chloroform contained in the filtrate was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (n-hexane / toluene = 4/1) to obtain the target product 1 (11.2 g).

In a nitrogen stream, target 1 (8.01 g), 2-hydroxybenzimidazole (1.04 g), copper powder (1.38 g), potassium carbonate (6.44 g), tetraglyme (20 ml) at 200 ° C. After stirring for 8 hours, the mixture was allowed to cool, copper powder (1.39 g) was added, and the mixture was stirred at 200 ° C. for 6 hours. After allowing to cool, chloroform and activated clay were added to the reaction mixture and stirred. Insoluble matter was filtered off, added to methanol (200 ml), stirred, and then the precipitate was collected by filtration. The obtained solid was purified by silica gel column chromatography (toluene), and washed with ethyl acetate and a chloroform / methanol mixture to obtain the desired product 2 (1.33 g).
DEI-MS m / z = 616 (M ⁺ )
This had a glass transition temperature of 146 ° C., a melting point of 355 ° C., and a vaporization temperature of 507 ° C.
The energy difference between the excited triplet state and the ground state of this product was 3.04 eV.

(Example 2: objects 3 and 4)

  In a nitrogen stream, 2-hydroxybenzimidazole (5.41 g), m-dibromobenzene (28.6 g), copper (I) iodide (15.3 g), potassium carbonate (22.3 g), N, N-dimethyl Formamide (130 ml) was stirred at 150 ° C. for 6.5 hours and allowed to cool to room temperature. Water was added to the reaction mixture, extracted with ethyl acetate, and the organic layer was dried over magnesium sulfate and concentrated. Toluene and activated clay were added to the concentrated residue, and the mixture was stirred and insoluble matter was filtered off. Chloroform contained in the filtrate was distilled off under reduced pressure, methanol was added and stirred, and the resulting precipitate was recrystallized from methanol to obtain the intended product 3 (4.36 g).

In a nitrogen stream, the target product 3 (4.36 g), carbazole (5.76 g), copper powder (1.88 g), potassium carbonate (8.15 g), tetraglyme (20 ml) were added at 210 ° C. for 7.5 hours. Stir. After allowing to cool, chloroform was added to the reaction mixture and stirred, insoluble matter was filtered off, added to methanol (200 ml), stirred, and then the precipitate was collected by filtration. The obtained solid was purified by silica gel column chromatography (toluene) and washed with a dichloromethane / methanol mixture to obtain the desired product 4 (2.29 g).
DEI-MS m / z = 616 (M ⁺ )
This had a glass transition temperature of 125 ° C., a melting point of 227 ° C., and a vaporization temperature of 489 ° C.
This dissolved in 3% by weight or more in toluene.
The energy difference between the excited triplet state and the ground state of this product was 2.99 eV.

(Example 3: object 5)

In a nitrogen stream, 1,3-bis (4-bromophenyl) -1,3-dihydrobenzimidazol-2-one (2.60 g), N- (4-biphenyl) aniline (4.31 g), tert-butoxy To a solution of sodium (2.25 g) and toluene (35 ml) was added tris (dibenzylideneacetone) dipalladium (0) chloroform complex (0.12 g), tri-tert-butylphosphine (0.209 g), and toluene ( 5 ml) was stirred at 60 ° C. for 5 minutes under a nitrogen atmosphere, and the solution was stirred for 9.5 hours under reflux with heating. After allowing to cool, activated clay and chloroform were added and stirred. The insoluble material was filtered off, added to methanol (200 ml), stirred, and the precipitate was collected by filtration. The obtained solid was purified by silica gel column chromatography (toluene) and washed with a dichloromethane / methanol mixture to obtain the desired product 5 (2.55 g).
DEI-MS m / z = 772 (M ⁺ )
This had a glass transition temperature of 124 ° C., no melting point was observed, and a vaporization temperature of 527 ° C. This dissolved in 5.0% by weight or more in toluene.

(Example 4: object 6)

In a nitrogen stream, 2-hydroxybenzimidazole (1.03 g), 3-bromobiphenyl (5.00 g), copper (I) iodide (2.92 g), potassium carbonate (4.23 g), N, N-dimethyl Formamide (10 ml) was stirred with heating under reflux for 8 hours and then allowed to cool. Chloroform was added to the reaction mixture and stirred, insoluble matter was filtered off, the filtrate was concentrated, purified by silica gel column chromatography, and suspended and washed with methanol to give the desired product 6 (2.68 g). Obtained.
EI-MS m / z = 438 (M ⁺ )
This had a glass transition temperature of 56 ° C., a melting point of 150 ° C., and a vaporization temperature of 391 ° C. This dissolved in 5.0% by weight or more in toluene.

(Example 5: objects 7 to 9)

  In a nitrogen stream, 2-hydroxybenzimidazole (6.53 g), iodobenzene (9.93 g), copper powder (3.11 g), potassium carbonate (13.5 g), and tetraglyme (15 ml) at 170 ° C. After stirring for 4 hours, the mixture was allowed to cool. Ethyl acetate and water are added to the reaction mixture and stirred. The organic layer is dried over magnesium sulfate, concentrated, purified by silica gel column chromatography (n-hexane / ethyl acetate mixture to ethyl acetate), and n-hexane. The target product 7 (3.87 g) was obtained by suspension washing.

  In a nitrogen stream, 2-hydroxybenzimidazole (7.58 g), p-dibromobenzene (40.0 g), copper powder (10.8 g), potassium carbonate (46.9 g), and tetraglyme (40 ml) After stirring at ° C for 12 hours, the mixture was allowed to cool. Ethyl acetate was added to the reaction mixture, and the mixture was stirred for 30 minutes under reflux with heating. After standing to cool, the insoluble material was filtered off, the filtrate was concentrated, the precipitate was suspended and washed with ethanol, and silica gel column chromatography (n- The product 8 (3.87 g) was obtained by purification with hexane / toluene mixture to toluene) and suspension washing with methanol.

In a nitrogen stream, target product 8 (0.860 g), target product 7 (1.22 g), copper powder (0.492 g), potassium carbonate (2.14 g), and tetraglyme (6 ml) were added at 200 ° C. at 14 ° C. After stirring for hours, the mixture was allowed to cool. Chloroform was added to the reaction mixture, the mixture was stirred for 30 minutes, the insoluble matter was filtered off, the filtrate was concentrated, the precipitate was suspended and washed with ethanol, and purified by silica gel column chromatography (n-hexane / ethyl acetate mixture). Then, suspension 9 was washed with an ethyl acetate / ethanol mixed solution to obtain the intended product 9 (0.465 g).
DEI-MS m / z = 702 (M ⁺ )
This had a glass transition temperature of 150 ° C., a melting point of 328 ° C., and a vaporization temperature of 527 ° C.
The energy difference between the excited triplet state and the ground state of this product was 3.2 eV or more.

(Example 6: objects 10 and 11)

  In a nitrogen stream, carbazole (18.8 g), 2,6-dibromopyridine (80.0 g), copper powder (14.4 g), potassium carbonate (31.2 g), and tetraglyme (80 ml) were heated to 170 ° C. The mixture was stirred for 7 hours under heating and allowed to cool to room temperature. Chloroform was added to the reaction mixture, and insoluble matters were filtered off. Chloroform contained in the filtrate was distilled off under reduced pressure, an ethanol / water (40/1) mixture was added, and the precipitate was separated by filtration. Water was added to the filtrate, and the precipitate was collected by filtration, washed with ethanol, and purified by silica gel column chromatography (n-hexane / methylene chloride mixed solution) to obtain the desired product 10 (17.7 g).

In a nitrogen stream, 2-hydroxybenzimidazole (0.724 g), target product 10 (7.50 g), copper (I) iodide (2.06 g), potassium carbonate (2.99 g), and N, N-dimethyl Formamide (17 ml) was stirred with heating under reflux for 10 hours and then allowed to cool. Methylene chloride and activated clay were added to the reaction mixture and stirred, the insoluble matter was filtered off, the filtrate was concentrated, and the precipitate was suspended and washed with methanol. Furthermore, the target product 11 (2.27 g) was obtained by suspension washing with a chloroform / methanol mixture and chloroform.
DEI-MS m / z = 618 (M ⁺ )
This had a glass transition temperature of 123 ° C., a melting point of 317 ° C., and a vaporization temperature of 500 ° C.
The energy difference between the excited triplet state and the ground state of this product was 3.00 eV.

(Example 7: object 12)

In a nitrogen stream, 9H-pyrido [3,4-b] indole (2.8 g), target product 3 (2.47 g), copper powder (1.06 g), potassium carbonate (4.6 g), and tetraglyme ( 8 ml) was heated and stirred at 180 ° C. for 8 hours.
After completion of the reaction, chloroform was added to the reaction mixture, and insoluble matters were filtered off. After the filtrate was concentrated, the precipitate was suspended and washed with methanol, and purified by silica gel column chromatography (ethyl acetate / methylene chloride mixed solution → ethanol / methylene chloride mixed solution) to obtain the target compound 12 (1.27 g). Got.
DEI-MS m / z = 617 (MH) ⁺
DCI-MS m / z = 619 (M + H) ⁺
This had a glass transition temperature of 135 ° C., a melting point of 221 ° C., and a vaporization temperature of 499 ° C.
This dissolved in 3% by weight or more in toluene.
The energy difference between the excited triplet state and the ground state of this product was 2.96 eV.

(Example 8: objects 13 and 14)

A concentrated hydrochloric acid aqueous solution (120 ml) was added to a suspension of 4-amino-3-nitrobenzene trifluoride (20.06 g) and ethanol (400 ml) in the air, and the mixture was heated to 80 ° C. with stirring. Reduced iron (27.09 g) was gradually added thereto over 15 minutes, and then stirred for 1 hour under heating and reflux. After cooling with ice, the resulting solution was neutralized with an aqueous ammonium hydroxide solution and extracted with dichloromethane. The extract was washed with water, concentrated, and purified by silica gel column chromatography to obtain 3,4-diaminobenzene trifluoride (12.495 g).
1,1′-carbonyldiimidazole (3.314 g) was added to a solution of 3,4-diaminobenzene trifluoride (3.0 g) and dehydrated tetrahydrofuran (100 ml) in a nitrogen stream under ice cooling at room temperature. Stir for 10.7 hours. After concentrating the obtained solution, methanol was added and irradiated with ultrasonic waves, followed by concentration, and the deposited precipitate was collected by filtration. This was purified by suspension washing in an ethanol / hexane mixed solvent and recrystallization from ethyl acetate to obtain the desired product 13 (1.203 g).
DEI-MS m / z = 202 (M ⁺ )

Mixture of the target compound 13 (1.188 g), the target compound 10 (5.125 g), CuI (2.26 g), potassium carbonate (3.28 g), and anhydrous N, N-dimethylformamide (19 ml) in a nitrogen stream The solution was stirred for 6.2 hours under heating to reflux. Further to this, the target product 10 (1.41 g), CuI (1.15 g) and potassium carbonate (1.8 g) were additionally added, and the mixture was stirred for 4.5 hours under heating to reflux. Methanol (30 ml) and water (30 ml) were added to the resulting solution, followed by filtration. The residue was poured into 150 ml of chloroform and stirred. Activated clay was added to the solution and stirred, followed by filtration. The filtrate was concentrated and purified by column chromatography on neutral spherical silica gel (developing solvent: hexane / methylene chloride), and then suspended and washed in methanol. The product was purified by hot washing in a mixed solvent of ethyl acetate and ethanol to obtain the desired product 14 (2.164 g).
DEI-MS m / z = 686 (M ⁺ )
This had a glass transition temperature of 126 ° C., a melting point of 282 ° C., and a vaporization temperature of 399 ° C.
The energy difference between the excited triplet state and the ground state of this product was 2.97 eV.

(Example 9: objects 15 and 16)

In a nitrogen stream, 1,1′-carbonyldiimidazole (15.5 g) was added to a solution of 2,3-diaminopyridine (8.7 g) and dehydrated tetrahydrofuran (500 ml) under ice-cooling and at room temperature for 14 hours. Stir. After concentration of the resulting solution, methanol was added to carry out a hot washing process, and the deposited precipitate was collected by filtration to obtain the intended product 15 (4.9 g).
DEI-MS m / z = 135 (M ⁺ )

In a nitrogen stream, the target compound 15 (1.0 g), N- (3-bromophenyl) carbazole (6.8 g), CuI (2.8 g), potassium carbonate (4.2 g), and anhydrous N, N-dimethyl A mixed solution of formamide (10 ml) was stirred for 6.2 hours with heating under reflux. Furthermore, the target product 10 (1.4 g), CuI (1.15 g), and potassium carbonate (1.8 g) were added thereto, and the mixture was stirred for 15 hours while heating under reflux. The reaction mixture was diluted with dichloromethane and then filtered, washed with brine, 1N hydrochloric acid and dried over sodium sulfate. The product which became brown oil by concentration under reduced pressure was purified by silica gel column chromatography (developing solvent: toluene), and then purified by suspension washing in methanol to obtain the target product 16 (1.1 g). It was.
DEI-MS m / z = 617 (M ⁺ )
This had a glass transition temperature of 125 ° C., a melting point of 226 ° C., and a vaporization temperature of 490 ° C.
This dissolved in 3% by weight or more in toluene.
The energy difference between the excited triplet state and the ground state of this product was 2.99 eV.

(Example 10: object 17)

In a nitrogen stream, the target product 7 (1.6 g), 6,6 ″ -dibromo-2,2 ′: 6 ′, 2 ″ -terpyridine (1.0 g), copper powder (0.35 g), potassium carbonate (1 4 g) and tetraglyme (5 ml) were added to a 100 mL four-necked flask, placed in an oil bath at 170 ° C. and stirred for 13 hours. The yellowish white solid obtained by diluting with dichloromethane and filtering and then distilling off under reduced pressure was heated and washed with tetrahydrofuran to obtain the desired product 17 (0.9 g) as a white powder.
DEI-MS m / z = 649 (M ⁺ )
This had a glass transition temperature of 118 ° C., a melting point of 276 ° C., and a vaporization temperature of 451 ° C.
The energy difference between the excited triplet state and the ground state of this product was 2.98 eV.

[Production Example of Organic Electroluminescent Device of the Present Invention]
Examples for producing the organic electroluminescence device of the present invention are shown below.

(Example 11)
An organic electroluminescent element having the structure shown in FIG. 7 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film 2 deposited on a glass substrate 1 with a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is formed into a 2 mm wide stripe using a normal photolithography technique and hydrochloric acid etching. The anode 2 was formed by patterning. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, then dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  As a material for the hole injection layer 3, a non-conjugated polymer compound (PB-2) having an aromatic amino group having the following structural formula is used together with an electron accepting compound (A-2) having the following structural formula. It spin-coated on the conditions of this.

Spin coating conditions
Solvent Anisole
PB-2 concentration 2 [wt%]
PB-2: A-2 10: 2 (weight ratio)
Spinner speed 2000 [rpm]
Spinner rotation time 30 [seconds]
Drying conditions 230 [° C] 15 [min]

  A uniform thin film having a thickness of 30 nm was formed by the above spin coating.

Next, the substrate on which the hole injection layer 3 was formed was placed in a vacuum evaporation apparatus. After roughly exhausting the apparatus with an oil rotary pump, the apparatus was evacuated with a cryopump until the degree of vacuum in the apparatus was 9.8 × 10 ⁻⁵ Pa (about 7.5 × 10 ⁻⁷ Torr) or less. . Vapor deposition was performed by heating an arylamine compound (H-1) having the structural formula shown below, placed in a ceramic crucible disposed in the apparatus, with a tantalum wire heater around the crucible. At this time, the temperature of the crucible was controlled in the range of 300 to 314 ° C. The degree of vacuum at the time of vapor deposition was 9.0 × 10 ⁻⁵ Pa (about 6.9 × 10 ⁻⁷ Torr), the vapor deposition rate was 0.1 nm / second, and a 40 nm thick hole transport layer 10 was formed.

  Subsequently, the target compound 4 synthesized in Example 2 as the main component (host material) of the light emitting layer 4: the organic iridium complex having the structural formula shown below as the subcomponent (dopant) of the organic compound (EM-1) of the present invention. (D-1) was placed in a separate ceramic crucible, and a film was formed by a binary simultaneous vapor deposition method.

The crucible temperature of the organic compound (EM-1) of the present invention is controlled at 270 to 284 ° C., the deposition rate is 0.1 nm / second, and the crucible temperature of the organic iridium complex (D-1) is controlled at 230 to 237 ° C., The light emitting layer 4 having a thickness of 30 nm and containing about 12.5 wt% of the organic iridium complex (D-1) was laminated on the hole transport layer 10. The degree of vacuum during vapor deposition was 7.4 × 10 ⁻⁵ Pa (about 5.7 × 10 ⁻⁷ Torr).

Further, as the hole blocking layer 8, a triarylbenzene derivative (HB-2) having the following structural formula was laminated at a crucible temperature of 343 to 350 ° C. with a deposition rate of 0.09 nm / second and a film thickness of 10 nm. The degree of vacuum during vapor deposition was 7.1 × 10 ⁻⁵ Pa (about 5.5 × 10 ⁻⁷ Torr).

Next, bathocuproine (ET-2) having the following structural formula was deposited on the hole blocking layer 8 as the electron transport layer 7 in the same manner. The crucible temperature of bathocuproine (ET-2) at this time is controlled in the range of 160 to 172 ° C., and the degree of vacuum at the time of vapor deposition is 6.6 × 10 ⁻⁵ Pa (about 5.1 × 10 ⁻⁷ Torr). The speed was 0.1 nm / second and the film thickness was 30 nm.

  The substrate temperature during vacuum deposition of the hole transport layer 10, the light emitting layer 4, the hole blocking layer 8 and the electron transport layer 7 was kept at room temperature.

Here, the element that has been deposited up to the electron transport layer 7 is once taken out from the vacuum deposition apparatus into the atmosphere, and a 2 mm wide striped shadow mask is used as a cathode deposition mask. In close contact with the element so as to be orthogonal to each other, it is installed in another vacuum deposition apparatus, and the degree of vacuum in the apparatus is 2.8 × 10 ⁻⁶ Torr (about 3.6 × 10 ⁻⁴ Pa) in the same manner as the organic layer. ) Exhaust until below. As the cathode 6, first, lithium fluoride (LiF) was deposited at a deposition rate of 0.03 nm / second and a degree of vacuum of 2.8 × 10 ⁻⁶ Torr (about 3.7 × 10 ⁻⁴ Pa) using a molybdenum boat. A film having a thickness of 0.5 nm was formed on the electron transport layer 7. Next, aluminum was similarly heated by a molybdenum boat, and an aluminum layer having a film thickness of 80 nm at a deposition rate of 0.2 nm / second and a degree of vacuum of 9.8 × 10 ⁻⁶ Torr (about 1.3 × 10 ⁻³ Pa). Thus, the cathode 6 was completed. The substrate temperature at the time of vapor deposition of the above two-layered cathode 6 was kept at room temperature.

As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The light emission characteristics of this device are shown in Tables 1 and 2.
The electroluminescence of this device was blue-green light emission having a maximum wavelength of 473 nm and a half-value width of 67 nm, and was identified to be from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.18, 0.38).

(Example 12)
An organic electroluminescent device having the structure shown in FIG. 7 was produced by the following method in the same manner as in Example 11 except that the light emitting layer 4 was formed by the method described below.
Target 16 synthesized in Example 9 as main component (host material) of light-emitting layer 4: Organic iridium complex (D) using organic compound (EM-3) of the present invention as subcomponent (dopant) in Example 11 -1) was placed in separate ceramic crucibles, and a film was formed by a binary simultaneous vapor deposition method.

The crucible temperature of the organic compound (EM-3) of the present invention is 400 to 407 ° C., the deposition rate is 0.1 nm / second, and the crucible temperature of the organic iridium complex (D-1) is controlled to 201 to 207 ° C., The light emitting layer 4 having a thickness of 30 nm and containing about 10.4 wt% of the organic iridium complex (D-1) was laminated on the hole transport layer 10. The degree of vacuum at the time of vapor deposition was 4.6 × 10 ⁻⁵ Pa (about 3.5 × 10 ⁻⁷ Torr).
The light emission characteristics of this element are shown in Table 2.
The electroluminescence of this element was blue-green light emission having a maximum wavelength of 471 nm and a half-value width of 53 nm, and was identified to be from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.14, 0.31).

(Example 13)
An organic electroluminescent device having the structure shown in FIG. 7 was produced by the following method in the same manner as in Example 11 except that the light emitting layer 4 was formed by the method described below.
Objective 12 synthesized in Example 7 as main component (host material) of light-emitting layer 4: Organic iridium complex (D) using organic compound (EM-4) of the present invention in Example 11 as subcomponent (dopant) -1) was placed in separate ceramic crucibles, and a film was formed by a binary simultaneous vapor deposition method.

The crucible temperature of the organic compound (EM-4) of the present invention is 217 to 242 ° C., the deposition rate is 0.09 nm / second, and the crucible temperature of the organic iridium complex (D-1) is controlled to 213 to 216 ° C. The light emitting layer 4 having a film thickness of 30 nm and containing about 13.1 wt% of the organic iridium complex (D-1) was laminated on the hole transport layer 10. The degree of vacuum during the deposition was 5.0 × 10 ⁻⁵ Pa (about 4.0 × 10 ⁻⁷ Torr).
The light emission characteristics of this element are shown in Table 2.
The electroluminescence of this element was blue-green light emission having a maximum wavelength of 472 nm and a half-value width of 53 nm, and was identified to be from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.15, 0.32).

(Comparative Example 1)
An organic electroluminescent device having the structure shown in FIG. 7 was produced by the following method in the same manner as in Example 11 except that the light emitting layer 4 was formed by the method described below.
The carbazole derivative (CBP) shown in the following structural formula as the main component (host material) of the light emitting layer 4 and the organic iridium complex (D-1) used in Example 11 as the subcomponent (dopant) are installed in separate ceramic crucibles. Then, a film was formed by a binary simultaneous vapor deposition method.

The crucible temperature of the carbazole derivative (CBP) is 411 to 406 ° C., the deposition rate is 0.08 nm / sec, the crucible temperature of the organic iridium complex (D-1) is controlled to 204 to 209 ° C., and the film thickness is 30 nm. The light emitting layer 4 containing about 13.1 wt% of the iridium complex (D-1) was laminated on the hole transport layer 10. The degree of vacuum during the deposition was 3.8 × 10 ⁻⁵ Pa (about 2.9 × 10 ⁻⁷ Torr).
The light emission characteristics of this device are shown in Tables 1 and 2.
The electroluminescence of this device was blue-green light emission having a maximum wavelength of 490 nm and a half width of 59 nm, and light emission from other materials was observed in addition to the light emission from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.19, 0.54).

(Example 14)
An organic electroluminescent element having the structure shown in FIG. 7 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film 2 deposited on a glass substrate 1 with a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is formed into a 2 mm wide stripe using a normal photolithography technique and hydrochloric acid etching. The anode 2 was formed by patterning. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, then dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  In Example 11, a non-conjugated polymer compound (PB-1) (weight average molecular weight: 29400, number average molecular weight: 12600) having an aromatic amino group represented by the structural formula shown below was used as a material for the hole injection layer 3. It spin-coated on the following conditions with the used electron-accepting compound (A-2).

Spin coating conditions
Solvent ethyl benzoate
PB-1 concentration 2 [wt%]
PB-1: A-2 10: 2 (weight ratio)
Spinner speed 1500 [rpm]
Spinner rotation time 30 [seconds]
Drying conditions 230 [° C] 15 [min]

  A uniform thin film having a thickness of 30 nm was formed by the above spin coating.

Next, the substrate on which the hole injection layer 3 was formed was placed in a vacuum evaporation apparatus. After roughly exhausting the apparatus with an oil rotary pump, the apparatus was exhausted with a cryopump until the degree of vacuum in the apparatus was 9.0 × 10 ⁻⁵ Pa (about 6.8 × 10 ⁻⁷ Torr) or less. . The arylamine compound (H-1) used in Example 11 placed in a ceramic crucible placed in the above apparatus was heated by a tantalum wire heater around the crucible for vapor deposition. At this time, the temperature of the crucible was controlled in the range of 300 to 314 ° C. The degree of vacuum at the time of vapor deposition was 9.3 × 10 ⁻⁵ Pa (about 7.0 × 10 ⁻⁷ Torr), the vapor deposition rate was 0.1 nm / second, and a 40 nm thick hole transport layer 10 was formed.

  Subsequently, the target compound 4 synthesized in Example 2 as the main component (host material) of the light emitting layer 4: the organic iridium complex having the structural formula shown below as the subcomponent (dopant) of the organic compound (EM-1) of the present invention. (D-2) was placed in separate ceramic crucibles, and a film was formed by a binary simultaneous vapor deposition method.

The crucible temperature of the organic compound (EM-1) of the present invention is 270 to 284 ° C., the deposition rate is 0.1 nm / second, and the crucible temperature of the organic iridium complex (D-2) is controlled to 245 to 246 ° C. The light emitting layer 4 having a thickness of 30 nm and containing about 5.9 wt% of the organic iridium complex (D-2) was laminated on the hole transport layer 10. The degree of vacuum during the deposition was 7.8 × 10 ⁻⁵ Pa (about 5.9 × 10 ⁻⁷ Torr).

Further, as the hole blocking layer 8, a phenylpyridine derivative (HB-1) having the structural formula shown below was laminated at a crucible temperature of 343 to 350 ° C. with a deposition rate of 0.09 nm / second and a film thickness of 10 nm. The degree of vacuum during vapor deposition was 7.1 × 10 ⁻⁵ Pa (about 5.5 × 10 ⁻⁷ Torr).

Next, tris (8-hydroxyquinolinato) aluminum (Alq3) having the following structural formula was deposited on the hole blocking layer 8 as the electron transport layer 7 in the same manner. At this time, the crucible temperature of tris (8-hydroxyquinolinato) aluminum (Alq3) is controlled in the range of 296 to 300 ° C., and the degree of vacuum at the time of deposition is 6.6 × 10 ⁻⁵ Pa (about 5.1 × 10 ⁻⁷ Torr), the deposition rate was 0.15 m / sec, and the film thickness was 30 nm.

  The substrate temperature during vacuum deposition of the hole transport layer 10, the light emitting layer 4, the hole blocking layer 8 and the electron transport layer 7 was kept at room temperature.

Thereafter, a two-layer cathode 6 was deposited in the same manner as in Example 11.
Table 3 shows the light emission characteristics of the device.
The electroluminescence of this device was green light emission having a maximum wavelength of 514 nm and a half width of 70 nm, and was identified as that from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.31, 0.62).

(Example 15)
An organic electroluminescent device having the structure shown in FIG. 7 was produced in the same manner as in the method shown in Example 14 except that the light emitting layer 4 was formed by the method described below.
Objective 11 synthesized in Example 6 as main component (host material) of light-emitting layer 4: Organic iridium complex (D) using organic compound (EM-5) of the present invention as subcomponent (dopant) in Example 14 -2) was placed in separate ceramic crucibles, and a film was formed by a binary simultaneous vapor deposition method.

The vapor deposition rate of the organic compound (EM-5) of the present invention is controlled to 0.1 nm / second, and the crucible temperature of the organic iridium complex (D-2) is controlled to 257 to 255 ° C., respectively, and the organic iridium complex ( The light emitting layer 4 containing about 6.2% by weight of D-2) was laminated on the hole transport layer 10. The degree of vacuum at the time of vapor deposition was 1.5 × 10 ⁻⁴ Pa.
Table 3 shows the light emission characteristics of the device.
The electroluminescence of this element was a green light emission having a maximum wavelength of 513 nm and a half-value width of 68 nm, and was identified to be from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.30, 0.62).

(Example 16)
An organic electroluminescent device having the structure shown in FIG. 7 was produced in the same manner as in the method shown in Example 14 except that the hole transport layer 10 and the light emitting layer 4 were formed by the method described below.
The substrate on which the hole injection layer 3 was formed was placed in a vacuum deposition apparatus. After roughly exhausting the apparatus with an oil rotary pump, the apparatus was evacuated with a cryopump until the degree of vacuum in the apparatus was 5.3 × 10 ⁻⁵ Pa (about 4.0 × 10 ⁻⁷ Torr) or less. . Vapor deposition was performed by heating an arylamine compound (PPD) having the structural formula shown below, placed in a ceramic crucible placed in the above apparatus, with a tantalum wire heater around the crucible. At this time, the temperature of the crucible was controlled in the range of 260 to 272 ° C. The degree of vacuum at the time of vapor deposition was 6.0 × 10 ⁻⁵ Pa (about 4.9 × 10 ⁻⁷ Torr), the vapor deposition rate was 0.1 nm / second, and a 40 nm thick hole transport layer 10 was formed.

  Subsequently, the target compound 2 synthesized in Example 1 as the main component (host material) of the light-emitting layer 4: the organic iridium complex in which the organic compound (EM-6) of the present invention was used as the subcomponent (dopant) in Example 14 (D-2) was placed in separate ceramic crucibles, and a film was formed by a binary simultaneous vapor deposition method.

The vapor deposition rate of the organic compound (EM-6) of the present invention is controlled to 0.1 nm / second, the crucible temperature of the organic iridium complex (D-2) is controlled to 268 to 270 ° C., and the organic iridium complex ( The light emitting layer 4 containing about 6.1% by weight of D-2) was laminated on the hole transport layer 10. The degree of vacuum during vapor deposition was 6.3 × 10 ⁻⁵ Pa (about 4.7 × 10 ⁻⁷ Torr).
Table 3 shows the light emission characteristics of the device.
The electroluminescence of this device was a green light emission having a maximum wavelength of 513 nm and a half-value width of 69 nm, and was identified as that from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.30, 0.58).

(Comparative Example 2)
An organic electroluminescent device having the structure shown in FIG. 7 was produced in the same manner as in the method shown in Example 14 except that the light emitting layer 4 was formed by the method described below.
The carbazole derivative (SiMCP) shown in the following structural formula as the main component (host material) of the light emitting layer 4 and the organic iridium complex (D-2) used in Example 14 as the subcomponent (dopant) are installed in separate ceramic crucibles. Then, a film was formed by a binary simultaneous vapor deposition method.

The deposition rate of the carbazole derivative (SiMCP) is controlled to 0.1 nm / second, the crucible temperature of the organic iridium complex (D-2) is controlled to 268 to 270 ° C., and the organic iridium complex (D-2) has a thickness of 30 nm. The light emitting layer 4 containing about 5.9 wt% was laminated on the hole transport layer 10. The degree of vacuum during vapor deposition was 6.3 × 10 ⁻⁵ Pa (about 4.7 × 10 ⁻⁷ Torr).
Table 3 shows the light emission characteristics of the device.
The electroluminescence of this device was green light emission having a maximum wavelength of 513 nm and a half-value width of 70 nm, and was identified to be from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.31, 0.68).

(Example 17 and Comparative Example 3)
Changes in luminance were observed when a direct current corresponding to a current density of 250 mA / cm ² was applied to the devices manufactured in Examples 14 to 16 and Comparative Example 2. Table 4 shows values obtained by dividing the luminance after 40 seconds of energization, the luminance immediately after energization, and the luminance value after 40 seconds of energization by the luminance value immediately after energization.

  From this result, the element using the compounds (EM-1), (EM-5) and (EM-6) of the present invention as the main component of the light emitting layer uses the carbazole derivative (SiMCP) as the main component of the light emitting layer. It was clarified that there was less decrease in luminance when energized than the conventional device.

(Example 18)
An organic electroluminescent device having the structure shown in FIG. 7 was produced by the following method in the same manner as in Example 14 except that the hole transport layer 10 and the light emitting layer 4 were formed by the method described below.
The substrate on which the hole injection layer 3 was formed was placed in a vacuum deposition apparatus. After roughly exhausting the apparatus with an oil rotary pump, the apparatus was evacuated with a cryopump until the degree of vacuum in the apparatus was 7.5 × 10 ⁻⁵ Pa (about 5.6 × 10 ⁻⁷ Torr) or less. . Target object 5 synthesized in Example 3 shown below, placed in a ceramic crucible placed in the above apparatus: The organic compound (EM-7) of the present invention is heated by a tantalum wire heater around the crucible and deposited. went. The degree of vacuum at the time of vapor deposition was 7.0 × 10 ⁻⁵ Pa, the vapor deposition rate was 0.1 nm / sec, and a hole transport layer 10 having a thickness of 40 nm was obtained.

  Subsequently, the carbazole derivative (E-1) shown below as the main component (host material) of the light-emitting layer 4 and the organic iridium complex (D-2) used in Example 14 as the subcomponent (dopant) were used as separate ceramics. It installed in the crucible and formed into a film by the binary simultaneous vapor deposition method.

The crucible temperature of the carbazole derivative (E-1) is 300 to 304 ° C., the deposition rate is 0.08 nm / sec, the crucible temperature of the organic iridium complex (D-2) is controlled to 239 to 242 ° C., and the film thickness is 30 nm. The light emitting layer 4 containing 6.4 wt% of the organic iridium complex (D-2) was laminated on the hole transport layer 10. The degree of vacuum at the time of vapor deposition was 6.6 × 10 ⁻⁵ Pa.
The light emission characteristics of this device are shown in Table 5.
The electroluminescence of this device was a green light emission having a maximum wavelength of 513 nm and a half-value width of 69 nm, and was identified as that from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.31, 0.62).

(Comparative Example 4)
An organic electroluminescent device having the structure shown in FIG. 7 was produced by the following method in the same manner as in Example 18 except that the hole transport layer 10 was formed by the method described below.
An arylamine compound (PPD) having the structural formula shown below was placed in a ceramic crucible and heated by a tantalum wire heater around the crucible for vapor deposition. The degree of vacuum during vapor deposition was controlled to 6.0 × 10 ⁻⁵ Pa and the vapor deposition rate was controlled to 0.08 to 0.13 nm / second to obtain a hole transport layer 10 having a thickness of 40 nm.

The light emission characteristics of this device are shown in Table 5.
The electroluminescence of this device was green light emission having a maximum wavelength of 513 nm and a half-value width of 67 nm, and was identified to be from the organic iridium complex (D-2). The chromaticity was CIE (x, y) = (0.30, 0.61).

(Example 19)
An organic electroluminescent element having the structure shown in FIG. 7 was produced by the following method.
In the same manner as in Example 14, after forming the hole injection layer 3 and the hole transport layer 10, the target product 4 synthesized in Example 2 as the main component (host material) of the light emitting layer 4: present An organic iridium complex (Facial body: D-3, Me is a methyl group) having the structural formula shown below as an accessory component (dopant) is placed in a separate ceramic crucible with the organic compound (EM-1) of the invention as a binary component (dopant). Film formation was performed by the co-evaporation method.

The crucible temperature of the organic compound (EM-1) of the present invention is controlled to 277 to 283 ° C., the deposition rate is 0.07 nm / second, and the crucible temperature of the organic iridium complex (D-3) is controlled to 279 to 281 ° C., respectively. The light emitting layer 4 having a film thickness of 30 nm and containing about 5.8 wt% of the organic iridium complex (D-3) was laminated on the hole transport layer 10. The degree of vacuum during the deposition was 5.0 × 10 ⁻⁵ Pa (about 3.8 × 10 ⁻⁷ Torr).

Furthermore, as the hole blocking layer 8, only the organic compound (EM-1) of the present invention was laminated with a crucible temperature of 283 to 297 ° C. and a film thickness of 10 nm at a deposition rate of 0.09 nm / second. The degree of vacuum during vapor deposition was 4.5 × 10 ⁻⁵ Pa (about 3.4 × 10 ⁻⁷ Torr).

Next, bathocuproine (ET-2) used in Example 11 was deposited on the hole blocking layer 8 as the electron transport layer 7 in the same manner. The crucible temperature of bathocuproine (ET-2) at this time is controlled in the range of 162 to 183 ° C., and the degree of vacuum at the time of vapor deposition is 4.4 × 10 ⁻⁵ Pa (about 3.3 × 10 ⁻⁷ Torr). The speed was 0.09 nm / second and the film thickness was 30 nm.

The substrate temperature during vacuum deposition of the hole transport layer 10, the light emitting layer 4, the hole blocking layer 8 and the electron transport layer 7 was kept at room temperature.
Thereafter, a two-layer cathode 6 was deposited in the same manner as in Example 11.
The light emission characteristics of this device are shown in Table 6.
The electroluminescence of this device was blue light emission with a maximum wavelength of 403 nm, and was identified as that from the organic iridium complex (D-3). The chromaticity was CIE (x, y) = (0.18, 0.10).

(Example 20)
An organic electroluminescent element having the structure shown in FIG. 7 was produced by the following method.
In the same manner as in Example 14, after forming the hole injection layer 3 and the hole transport layer 10, the target 11 synthesized in Example 6 as the main component (host material) of the light emitting layer 4: present The organic iridium complex (D-1) used in Example 11 as the secondary component (dopant) of the organic compound (EM-5) of the invention was placed in a separate ceramic crucible, and film formation was performed by a binary simultaneous vapor deposition method. It was.

The vapor deposition rate of the organic compound (EM-5) of the present invention is controlled to 0.1 nm / second, the crucible temperature of the organic iridium complex (D-1) is controlled to 252 to 260 ° C., respectively, and the organic iridium complex ( The light emitting layer 4 containing about 7.6% by weight of D-1) was laminated on the hole transport layer 10. The degree of vacuum at the time of deposition was 4.2 × 10 ⁻⁵ Pa.

Further, as the hole blocking layer 8, the phenylpyridine derivative (HB-1) used in Example 14 was laminated at a crucible temperature of 340 to 341 ° C. with a deposition rate of 0.08 to 0.09 nm / second and a film thickness of 5 nm. did. The degree of vacuum at the time of vapor deposition was 4.6 × 10 ⁻⁵ Pa.

Next, bis (2-methyl 8-hydroxyquinolinato) (p-phenylphenolate) aluminum (BAlq) having the following structural formula is deposited on the hole blocking layer 8 as the electron transport layer 7 in the same manner. did. At this time, the crucible temperature of bis (2-methyl 8-hydroxyquinolinato) (p-phenylphenolate) aluminum (BAlq) was controlled in the range of 190 to 191 ° C., and the degree of vacuum during the deposition was 5.1 × 10. ⁻⁵ Pa, the deposition rate was controlled at 0.08 to 0.24 m / sec, and the film thickness was 30 nm.

The substrate temperature during vacuum deposition of the hole transport layer 10, the light emitting layer 4, the hole blocking layer 8 and the electron transport layer 7 was kept at room temperature.
Thereafter, a two-layer cathode 6 was deposited in the same manner as in Example 11.

The light emission characteristics of this device are shown in Table 7.
The electroluminescence of this element was blue-green light emission having a maximum wavelength of 471 nm and a half-value width of 66 nm, and was identified to be from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.17, 0.36).

(Example 21)
An organic electroluminescent device having the structure shown in FIG. 3 (however, having no electron injection layer) was produced by the following method.
An indium tin oxide (ITO) transparent conductive film 2 deposited on a glass substrate 1 with a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is formed into a 2 mm wide stripe using a normal photolithography technique and hydrochloric acid etching. The anode 2 was formed by patterning. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, then dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  Next, the hole injection layer 3 was formed in the same manner as in Example 11 except that the drying conditions at the time of spin coating were 230 ° C. and 180 minutes.

  Subsequently, the light emitting layer 4 was formed on the hole injection layer 3 by a wet film forming method as follows. As the material of the light-emitting layer 4, the target compound 4 synthesized in Example 2: the organic compound (EM-1) of the present invention and the organic iridium complex (D-1) used in Example 11 were used, and these were used as a solvent. A composition for an organic electroluminescence device was prepared by dissolving in the solution, and spin coating was performed using the composition for an organic electroluminescence device under the following conditions.

Spin coating conditions
Solvent Toluene
EM-1 concentration 2 [wt%]
EM-1: D-1 10: 1 (weight ratio)
Spinner speed 1500 [rpm]
Spinner rotation time 60 [seconds]
Drying conditions 100 [° C], 60 [min] (under reduced pressure)

  A uniform thin film having a thickness of 65 nm was formed by the above spin coating.

Next, a hole blocking layer 8, an electron transport layer 7, and a cathode 6 were formed in the same manner as in Example 11.
As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The light emission characteristics of this device are shown in Table 8.

  The electroluminescence of this device was blue-green light emission having a maximum wavelength of 471 nm and a half-value width of 67 nm, and was identified to be from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.18, 0.36).

It is typical sectional drawing which showed an example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of the organic electroluminescent element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Light emitting layer 5 Electron injection layer 6 Cathode 7 Electron transport layer 8 Hole blocking layer 9 Electron blocking layer 10 Hole transport layer

Claims (12)

An organic compound represented by the following formula (I).

[Wherein, Ar ¹ is represented by the following substituent an aromatic optionally having a substituent selected from the group Z hydrocarbon group, an aromatic heterocyclic which may have a substituent selected from Substituent Group Z It represents a cyclic group or an alkyl group which may have a substituent selected from the following substituent group Z.
The Ar ² is represented by the following aromatic optionally having a substituent selected from substituent group Z hydrocarbon group or an aromatic optionally having a substituent selected from Substituent Group Z heterocyclic group, Represent.
Substituent group Z: groups R ¹ and R ² derived from an aromatic hydrocarbon group, an alkyl group and 1,3-dihydroimidazol-2-one each independently represent a hydrogen atom , an aromatic hydrocarbon group or an alkyl group . Alternatively, as represented by the following formula (II), they are bonded to each other and may have an aromatic hydrocarbon group and / or an alkyl group as a substituent, or aromatic as a substituent It has a hydrocarbon group and / or an alkyl group to form a ring a ¹ of the nitrogen-containing aromatic six-membered ring.

(In the formula, Ar ¹ , Ar ² and Q have the same meanings as in the formula (I)).
Ring A ¹ includes a benzene ring which may have an aromatic hydrocarbon group and / or an alkyl group as a substituent, or an aromatic hydrocarbon group and / or an alkyl group which may have a substituent. Represents a nitrogen aromatic six-membered ring. )
Q is represented by the following formula (I-1 ) .

(In the formula, Ar ^{3 to} Ar ⁴ each independently has an aromatic hydrocarbon group which may have a substituent selected from the following substituent group Z , or a substituent selected from the following substituent group Z. And Ar ³ and Ar ⁴ may be bonded to each other to form a ring.
Substituent group Z: aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one-derived group )] The organic compound of Claim 1 represented by following formula (III).

[Wherein, R ¹ , R ² and Q have the same meanings as in the formula (I).
Ring B ¹ represents a benzene ring that may have a substituent selected from the following substituent group Z , and ring C ¹ may have a substituent selected from the following substituent group Z in addition to Q. Represents a benzene ring.
Substituent group Z: group derived from aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one ] The organic compound according to claim 1, which is represented by the following formula (III-2).

[Wherein, R ¹ , R ² and Q have the same meanings as in the formula (I).
Ring D ¹ represents a pyridine ring which may have a substituent selected from the following substituent group Z , and ring E ¹ may have a substituent selected from the following substituent group Z in addition to Q. Represents a pyridine ring.
Substituent group Z: group derived from aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one ] The organic compound of Claim 1 represented by following formula (IV).

^{Wherein, Ar 2 ~Ar 4, R 1} , R 2 have the same meanings as in the formula (I) and formula (I-1).
To Ar ⁶ to Ar ⁸ each independently have a substituent selected from the following substituent an aromatic optionally having a substituent selected from the group Z hydrocarbon group or the following substituent group Z, Represents a good aromatic heterocyclic group. Ar ⁷ and Ar ⁸ may be bonded to each other to form a ring.
Substituent group Z: group derived from aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one ] The organic compound according to any one of claims 1 to 4 , which has an N-carbazolyl group represented by the following formula (I-3) as a partial structure.

A charge transport material comprising the organic compound according to any one of claims 1 to 5 . A charge transport material for an organic electroluminescence device represented by the following formula (II-2).

Wherein ring A ¹ is has an aromatic hydrocarbon group and / or a benzene ring which may have an alkyl group or an aromatic as a substituent a hydrocarbon group and / or an alkyl group, as a substituent Represents a nitrogen-containing aromatic six-membered ring which may be
Ar ^1, Ar ⁹ each independently have a substituent selected from the following substituent an aromatic optionally having a substituent selected from the group Z hydrocarbon group or the following substituent group Z, Represents a good aromatic heterocyclic group.
Substituent group Z: group derived from aromatic hydrocarbon group, alkyl group and 1,3-dihydroimidazol-2-one ] The charge transport material according to claim 6 or 7 , which dissolves 2.0% by weight or more in toluene. The composition for charge transport materials containing the charge transport material as described in any one of Claims 6 thru | or 8 . Furthermore, the composition for charge transport materials of Claim 9 containing a phosphorescence-emitting material. 9. An organic electroluminescence device having an anode, a cathode, and a light emitting layer provided between the two electrodes on a substrate, comprising a layer comprising the charge transport material according to any one of claims 6 to 8. Organic electroluminescent device. The organic electroluminescence device according to claim 11 , wherein the layer containing the charge transport material is a layer formed using the composition for charge transport material according to claim 9 or 10 .

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