JP2007067383A - Charge transport material, organic electroluminescent element, and composition thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge transport material which is soluble in various solvents, being high in charge transportation capability, and is not easily crystallized, a composition for forming an organic electroluminescent element which can be driven at a low voltage, and to provide the organic electroluminescent element using the same. <P>SOLUTION: The charge transport material is expressed by the formula (I). Wherein, rings A-E are each benzene ring that may have substituent or pyridine ring that may have substituent. Ar<SP>1</SP>-Ar<SP>4</SP>are each aromatic hydrocarbon or aromatic heterocycle that may have substituent. Q<SP>1</SP>and Q<SP>2</SP>are each direct coupling or bivalent linkage derived from aromatic hydrocarbon ring that may have substituent or aromatic heterocycle that may have substituent, connecting any one of rings A-E to nitrogen atom. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a charge transport material that is soluble in various solvents, has a high charge transport ability, and does not easily crystallize, a composition for an organic electroluminescent device containing the charge transport material, and the charge transport material. The present invention relates to an organic electroluminescent device having a layer and having high luminous efficiency and high driving stability.

  In recent years, an electroluminescent element (organic electroluminescent element) using an organic thin film has been developed. Examples of the method for forming the organic thin film in the organic electroluminescent device include a vacuum deposition method and a wet film forming method. Among these, the wet film-forming method does not require a vacuum process, is easy to increase in area, and can easily mix a plurality of materials having various functions into one layer (coating liquid). There are advantages.

Polymer materials such as poly (p-phenylene vinylene) derivatives and polyfluorene derivatives are mainly used as the material for the light emitting layer formed by the wet film forming method. There's a problem.
・ 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.

  Due to the above-mentioned problems, an element using a wet film forming method is inferior in driving stability to an element using a vacuum vapor deposition method, and has not reached a practical level except for a part.

  As an attempt to solve the above problems, Patent Document 1 uses an organic thin film formed by a wet film-forming method by mixing a plurality of low-molecular materials (charge transport materials, light-emitting materials), not a polymer compound. Organic electroluminescent devices are described. However, since the organic electroluminescent element described in Patent Document 1 uses fluorescent light emission, the light emission efficiency and the maximum light emission luminance of the element are low, and the practical characteristics are not satisfied.

In an organic electroluminescent element using an organic thin film made of a plurality of low molecular materials formed by a wet film forming method, Non-Patent Document 1 describes an element using phosphorescence emission in order to increase the luminous efficiency of the element. ing. The charge transport material of the organic electroluminescence device described in Non-Patent Document 1 uses the following biphenyl derivative.

  However, the biphenyl derivative is very easy to crystallize, and it has been difficult to obtain a uniform amorphous film by a wet film forming method. Furthermore, the biphenyl derivative has low solubility in a solvent. For this reason, it is necessary to use a halogen-based solvent such as chloroform or 1,2-dichloroethane as a coating solvent, but the halogen-based solvent has a large environmental load and has a practical problem. In addition, since there is a high possibility that the material is deteriorated by impurities contained in the halogen-based solvent, it is conceivable that the driving stability of the element formed by the wet film forming method using the halogen-based solvent is not sufficient.

Patent Document 2 exemplifies the following compounds for the purpose of improving the heat resistance of a charge transport material containing a carbazolyl group.

  The above compound is considered to be relatively difficult to crystallize because it has a partial structure in which five benzene rings linked at the m-position are continuous. However, since it has only one carbazolyl group, it has poor charge transport ability. . Furthermore, in the above compound, since the carbazolyl group is substituted only on the central benzene ring in the partial structure in which five benzene rings are continuous, HOMO tends to be localized in the center of the molecule. It is thought that the transport ability is poor, and improvement is necessary as a material of the organic electroluminescence device. In addition, since a compound in which HOMO is localized at the center of the molecule is considered not to be sufficiently soluble in a solvent, the above compound is not suitable for forming a thin film by a wet film forming method.

Patent Document 2 also exemplifies the compounds shown below.

  Although the above compound has two carbazolyl groups, like the compounds H-4 and H-5 described above, HOMO has a tendency to localize in the center of the molecule, has a poor charge transport ability, and dissolves in a solvent. Therefore, it is necessary to improve the material of the organic electroluminescent element, and it is not suitable for forming a thin film by a wet film forming method.

Patent Document 3 discloses the following compounds.

The above compound has a partial structure in which five benzene rings or pyridine rings connected at the m-position are connected, but two of the five rings are pyridine rings, and thus are useful as a coating solvent in a wet film forming method. Solubility in low hydrocarbon solvents is low. Moreover, since the crystallinity tends to increase as the ratio of the pyridine ring to the ring in the compound increases, the above compound is not suitable for forming a thin film by a wet film forming method.
Japanese Patent Laid-Open No. 11-238359 WO2004 / 074399 WO2005 / 022962 Japanese Journal of Applied Physics Vol.44, No.1B, 2005, pp.626-629

  The present invention has been made in view of the above-described conventional situation, and provides a charge transporting material that is soluble in various solvents, has a high charge transporting ability, and does not easily crystallize. An object of the present invention is to provide a composition for forming an organic electroluminescent device that is excellent in properties and can be driven at a low voltage, and an organic electroluminescent device using the composition.

  As a result of intensive studies by the present inventors, an organic compound having the following structure is excellent in solubility in a solvent and has a high amorphous property, so that a thin film can be formed by a wet film formation method. Since organic compounds have excellent charge transport properties, they have found that when used in organic electroluminescent devices, they exhibit high driving stability and can be driven with a low driving voltage, and the present invention has been achieved.

  That is, the gist of the present invention resides in a charge transport material represented by the following general formula (I) (claim 1).

  Another subject matter of the present invention resides in a composition for an organic electroluminescent device comprising the charge transport material (claim 6).

  Still another subject matter of the present invention is an organic electroluminescent device having an anode, a cathode, and an organic light emitting layer provided between both electrodes on a substrate, characterized by having a layer containing this charge transport material. An organic electroluminescent device (claim 9).

（一般式（Ｉ）中、環Ａ〜環Ｅは各々独立に、置換基を有していてもよいベンゼン環、又は置換基を有していてもよいピリジン環を表す。ただし、環Ａ〜環Ｅのうち、２つ以上がピリジン環であることはない。
Ａｒ^１〜Ａｒ^４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、又は置換基を有していてもよい芳香族複素環基を表す。なお、Ａｒ^１とＡｒ^２、Ａｒ^１とＱ^１が有する置換基、Ａｒ^３とＡｒ^４、Ａｒ^３とＱ^２が有する置換基は、互いに結合して、各々独立に、置換基を有していてもよい環を形成してもよい。
Ｑ^１、Ｑ^２は各々独立に、環Ａ〜環Ｅのいずれか１つと窒素原子とを連結する、置換基を有していてもよい芳香族炭化水素環、又は置換基を有していてもよい芳香族複素環由来の２価の連結基、或いは直接結合を表す。ただし、Ｑ^１、Ｑ^２は、環Ａ〜環Ｅのうち、それぞれ異なる環に結合する。）

(In general formula (I), each of ring A to ring E independently represents a benzene ring which may have a substituent, or a pyridine ring which may have a substituent. Two or more of the rings E are not pyridine rings.
Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ¹ and Ar ² , Ar ¹ and Q ¹ have substituents, Ar ³ and Ar ⁴ , Ar ³ and Q ² have substituents which are bonded to each other and each independently has a substituent. An optional ring may be formed.
Q ¹ and Q ² each independently have an aromatic hydrocarbon ring that may have a substituent, or a substituent that connects any one of ring A to ring E to a nitrogen atom. Represents a divalent linking group derived from an aromatic heterocycle or a direct bond. However, Q < ¹ >, Q < ² > ^couple | bonds with a ring which is different among ring A-ring E, respectively. )

  According to the charge transport material of the present invention and the composition for an organic electroluminescence device containing the charge transport material, a uniform organic thin film containing a material having a high charge transport capability can be easily formed by a wet film forming method. It is easy to increase the area of the organic electroluminescent device. Furthermore, according to the organic electroluminescent device using the charge transport material of the present invention and the composition for organic electroluminescent device containing the charge transport material, it is possible to emit light at a low voltage, and the stability of the device, particularly Drive stability is improved.

  Further, the charge transport material of the present invention can be applied to film formation by a vacuum deposition method or film formation by a wet film formation method because of excellent film forming properties, charge transport properties, light emission characteristics, and heat resistance.

  In addition, the charge transport material of the present invention and the composition for an organic electroluminescence device containing the charge transport material are suitable for the layer structure of the device because of excellent film forming properties, charge transport properties, light emission characteristics, and heat resistance. It can also be applied as a hole injection material, a hole transport material, a light emitting material, a host material, an electron injection material, an electron transport material, and the like.

  Accordingly, the organic electroluminescent device using the charge transport material of the present invention and the organic electroluminescent device composition containing the charge transport material is a flat panel display (for example, for OA computers or wall-mounted televisions), an in-vehicle display device, a mobile phone. It can be applied to light sources (for example, light sources for copiers, backlights for liquid crystal displays and instruments), display panels, and beacon lamps that take advantage of the characteristics of telephone displays and surface light emitters, and their technical value is great. Is.

  In addition, the charge transport material of the present invention and the composition for organic electroluminescent elements containing the charge transport material have essentially excellent redox stability, and thus are not limited to organic electroluminescent elements, and other electrophotography. It can also be used effectively for a photoreceptor.

  Hereinafter, embodiments of the charge transport material, the composition for an organic electroluminescent element, and the organic electroluminescent element of the present invention will be described in detail. However, the description of the constituent elements described below is an example of the embodiment of the present invention ( The present invention is not limited to these contents unless it exceeds the gist.

[Charge transport material]
The charge transport material of the present invention is a charge transport material represented by the following general formula (I), and is particularly preferably used for an organic electroluminescence device.

（一般式（Ｉ）中、環Ａ〜環Ｅは各々独立に、置換基を有していてもよいベンゼン環、又は置換基を有していてもよいピリジン環を表す。ただし、環Ａ〜環Ｅのうち、２つ以上がピリジン環であることはない。
Ａｒ^１〜Ａｒ^４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、又は置換基を有していてもよい芳香族複素環基を表す。なお、Ａｒ^１とＡｒ^２、Ａｒ^１とＱ^１が有する置換基、Ａｒ^３とＡｒ^４、Ａｒ^３とＱ^２が有する置換基は、互いに結合して、各々独立に、置換基を有していてもよい環を形成してもよい。
Ｑ^１、Ｑ^２は各々独立に、環Ａ〜環Ｅのいずれか１つと窒素原子とを連結する、置換基を有していてもよい芳香族炭化水素環、又は置換基を有していてもよい芳香族複素環由来の２価の連結基、或いは直接結合を表す。ただし、Ｑ^１、Ｑ^２は、環Ａ〜環Ｅのうち、それぞれ異なる環に結合する。）

(In general formula (I), each of ring A to ring E independently represents a benzene ring which may have a substituent, or a pyridine ring which may have a substituent. Two or more of the rings E are not pyridine rings.
Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ¹ and Ar ² , Ar ¹ and Q ¹ have substituents, Ar ³ and Ar ⁴ , Ar ³ and Q ² have substituents which are bonded to each other and each independently has a substituent. An optional ring may be formed.
Q ¹ and Q ² each independently have an aromatic hydrocarbon ring that may have a substituent, or a substituent that connects any one of ring A to ring E to a nitrogen atom. Represents a divalent linking group derived from an aromatic heterocycle or a direct bond. However, Q < ¹ >, Q < ² > ^couple | bonds with a ring which is different among ring A-ring E, respectively. )

  Hereinafter, the charge transport material represented by the general formula (I) will be described.

[1] Structural features Since the charge transport material of the present invention has a partial structure in which five benzene rings or pyridine rings linked at the m-position are linked, the solubility in a solvent is extremely high, and the amorphous material is amorphous. Therefore, it is possible to form an amorphous organic thin film that does not easily crystallize. Moreover, since it has two or more diarylamino groups, it has excellent charge transportability.

[2] Molecular Weight Range The molecular weight of the charge transport material of the present invention is usually 5000 or less, preferably 4000 or less, more preferably 3000 or less, and usually 200 or more, preferably 300 or more, more preferably 400 or more. If the molecular weight exceeds this upper limit, purification may be difficult due to the high molecular weight of impurities, and if the molecular weight falls below this lower limit, the glass transition temperature, melting point, vaporization temperature, etc. will decrease. There is a risk that the properties are significantly impaired.

[3] Physical Properties Although the charge transport material of the present invention usually has a glass transition temperature of 50 ° C. or higher, from the viewpoint of heat resistance, the glass transition temperature is preferably 80 ° C. or higher, and preferably 110 ° C. or higher. Further preferred.

  The charge transport material of the present invention usually has a vaporization temperature of 300 ° C. or higher and 800 ° C. or lower.

  In addition, the charge transport material of the present invention preferably has no crystallization temperature between the glass transition temperature and the vaporization temperature.

  Further, the charge transport material of the present invention has good solvent solubility. For example, the solubility in toluene is preferably 2% by weight or more, particularly 5% by weight or more at 25 ° C. and atmospheric pressure. The upper limit of the solubility is not particularly defined, but is usually 50% by weight or less.

[4] Ring A to Ring E
Ring A to ring E in the charge transport material of the present invention may each independently have an arbitrary substituent (in the present invention, “may have a substituent” means “ It represents “may have one or more substituents”.) Represents a benzene ring or a pyridine ring optionally having a substituent. However, two or more of ring A to ring E are not pyridine rings. That is, ring A to ring E are all benzene rings, or one is a pyridine ring and four are benzene rings. When there are two or more pyridine rings among ring A to ring E, the crystallinity of the compound represented by the general formula (I) tends to be high. It may be appropriate.
Ring A to ring E can each have a substituent having a molecular weight of 1000 or less at one substitution position. The substituent referred to here may be one formed by connecting a plurality of substituents of ring A to ring E specifically exemplified below.

  Specific examples of the optional substituent that ring A to ring E may have 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, and a tert-butyl group.)
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl, 1-butenyl group, etc.).
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, And dibenzylamino group.)
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, etc.)]
An alkoxy group that may have a substituent (preferably an alkoxy group having 1 to 8 carbon atoms that may have a substituent, such as methoxy, ethoxy, and butoxy groups).
An aryloxy group which may have a substituent (preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy and 2-naphthyloxy groups) )
A heteroaryloxy group which may have a substituent (preferably has a 5- or 6-membered aromatic heterocyclic group, and examples thereof include a pyridyloxy and thienyloxy group).
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, such as methoxycarbonyl and ethoxycarbonyl groups).
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).
A halogen atom (preferably a fluorine atom or a chlorine atom)
Carboxyl group Cyano group Hydroxyl group Mercapto group Alkylthio group which may have a substituent (preferably an alkylthio group having 1 to 8 carbon atoms, such as methylthio group and 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 (eg, 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 monovalent groups derived from 5- or 6-membered monocyclic rings or 2 to 5 condensed rings.)
An aromatic 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, pyrrolo) Imidazole 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, Monovalent groups derived from 5- or 6-membered monocyclic or 2-4 condensed rings such as pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring Can be mentioned.)

  When the above substituent further has a substituent, examples of the substituent include the above exemplified substituents.

  As the substituent of ring A to ring E, an aromatic hydrocarbon group which may have a substituent is preferable from the viewpoint of improving electrochemical durability and heat resistance, and more preferably. A phenyl group which may have a substituent, more preferably an unsubstituted phenyl group, or a mono- or di-substituted phenyl group.

  As the substituent of ring A to ring E, an alkyl group which may have a substituent is preferable from the viewpoint of further improving solubility and amorphousness, and more preferably a methyl group, an ethyl group, n -Propyl group, 2-propyl group, n-butyl group, isobutyl group, tert-butyl group, more preferably methyl group or ethyl group.

  Ring A to ring E are all preferably benzene rings in terms of particularly high solubility, that is, represented by the following formula (IV-1).

  Ring A to ring E are preferably represented by the following formulas (IV-2) to (IV-4) in that they have high electron transport properties and high electrochemical stability. It is particularly preferred that it is represented by IV-2).

  When ring A to ring E are represented by the above formulas (IV-2) to (IV-4), from the viewpoint of further improving the electrochemical durability and the heat resistance, respectively, More preferably, the p-position of N is substituted with an arbitrary substituent, more preferably an aromatic hydrocarbon group which may have a substituent, and mono- or disubstituted phenyl. Most preferably, it is substituted with a group or an unsubstituted phenyl group.

[5] Ar ¹ Ar ² N-, Ar ³ Ar ⁴ N-
Ar ^{1 to} Ar ⁴ in the charge transport material of the present invention are each independently an aromatic hydrocarbon group which may have an arbitrary substituent, or an aromatic heterocycle which may have an arbitrary substituent. Represents a group.

  Examples of the aromatic hydrocarbon group include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, and fluoranthene ring. Examples thereof include monovalent groups derived from a 6-membered monocyclic ring or a 2-5 condensed ring.

  Examples of the aromatic heterocyclic group include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolo Pyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyrazine 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. Environment The include monovalent groups.

If the arbitrary substituent which Ar < ¹ > -Ar < ⁴ > may have is illustrated, the group mentioned above will be mentioned as a substituent which the ring A-ring E may have.

Ar ^{1 to} 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. A phenyl group which may be substituted, more preferably an unsubstituted phenyl group or a mono- or di-substituted phenyl group.

Ar ¹ and Ar ² , Ar ³ and Ar ⁴ may be bonded to each other to independently form a ring which may have a substituent. Preferred examples of Ar ¹ Ar ² N- or Ar ³ Ar ⁴ N- in the case where Ar ¹ and Ar ² or 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.

[6] Q ¹ and Q ²
Q ¹ and Q ² each independently have an optionally substituted aromatic hydrocarbon ring or an arbitrary substituent that connects any one of ring A to ring E to a nitrogen atom. It represents a divalent linking group derived from an aromatic heterocyclic ring (including a group in which two or more aromatic hydrocarbon rings and / or aromatic heterocyclic rings are linked), or a direct bond. However, Q ¹ and Q ² are each bonded to different rings among the rings A to E.

  Examples of the divalent linking group derived from the aromatic hydrocarbon ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene. Examples thereof include a bivalent group derived from a 6-membered monocyclic ring or a 2-5 condensed ring, such as a ring and a fluoranthene ring.

  Examples of the divalent linking group derived from the aromatic heterocycle 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, benzoisothiazole 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. Ring or From 2 to 4 fused rings, divalent group.

If the arbitrary substituent which Q < ¹ >, Q < ² > may have is illustrated, the group mentioned above as a substituent which the ring A-the ring E may have is mentioned.

Q ¹ and Q ² are, from the viewpoint of improving electrochemical durability, a divalent group derived from a benzene ring, a divalent group in which a plurality of benzene rings are linked (for example, biphenylenyl group, terphenylenyl group, etc.), or A direct bond is preferable, and a m-phenylene group, a p-phenylene group, or a direct bond is more preferable from the viewpoint of preventing a decrease in triplet excited level. Q ¹ and Q ² are particularly preferably a p-phenylene group or a direct bond from the viewpoint of high electrochemical stability, and are an m-phenylene group or a direct bond from the viewpoint of further improving the solubility. It is particularly preferred.

In particular, in the charge transport material of the present invention represented by the general formula (I), Q ¹ is connected to the ring A and Q ² is connected to the ring E as shown in the following general formula (II). It is preferable because it has very high solubility.

などが挙げられる。 Incidentally, a substituent substituted group of the Ar ¹ and to Q ¹ described above, the Ar ^3, Q ² has are linked together each independently may form a ring which may have a substituent .
As such a ring,

Etc.

[7] Illustrative Examples Hereinafter, preferred specific examples of the charge transport material of the present invention will be shown, but the present invention is not limited thereto. In the following exemplary compounds, when two N-carbazolyl groups are bonded to one ring among five rings connected at the m-position corresponding to ring A to ring E, one N -The carbazolyl group is introduced as a substituent and does not correspond to Ar ¹ Ar ² N- or Ar ³ Ar ⁴ N-.

[8] Synthesis Method The charge transport material of the present invention represented by the general formula (I) 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 methods [A] to [C].

[A] Starting from a 2 or 2 or more substituted halide (X-Ar-X, preferably X = Br, I) having a partial structure in which five benzene rings or five pyridine rings linked at the m-position are linked Using this starting material and a secondary amine (Ar ¹¹ Ar ¹² NH), copper powder, copper wire, copper halide (CuX (X = Cl, Br, I)), copper oxide (CuO), etc. Catalysts (about 0.1 to 5 equivalents relative to the starting halogen atom) and basic substances such as potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert-butoxy sodium (based on the starting halogen atom) In the presence of about 1 to 10 equivalents), in an inert gas stream, no solvent, or an aromatic solvent such as nitrobenzene, a solvent such as tetraglyme, polyethylene glycol, and the like, A method of stirring and mixing in a temperature range for 1 to 60 hours.

[B] Starting with two or more substituted halides (X-Ar-X, preferably X = Cl, Br, I) having a partial structure in which five benzene rings or five pyridine rings connected at the m-position are connected Used as a raw material, this starting material and a secondary amine (Ar ¹¹ Ar ¹² NH) are converted into Pd ₂ (dba) ₃ (Pd = palladium, dba = dibenzylideneacetone), Pd (dba) ₂ , palladium acetate, etc. Bivalent palladium catalyst, BINAP (= 2,2′-bis (diphenylphosphino-1,1′-binaphthyl), tri (tert-butyl) phosphine, triphenylphosphine, 1,2-bis (diphenylphosphine) Fino) ethane, 1,3-bis (diphenylphosphino) propane, 1,3-bis (diphenylphosphino) butane, dppf (= 1, '- bis (diphenylphosphino) ferrocene) a combination of ligands such as, or Pd _(PPh) 0-valent palladium complexes such as _4, or PdCl _{2 (dppf)} catalyst such as palladium chloride complex such as ₂ (starting material 0.001 to 1 equivalent with respect to the halogen atom of) and a basic substance such as tert-butoxy potassium, tert-butoxy sodium, potassium carbonate, cesium carbonate, triethylamine (usually with respect to the halogen atom of the starting material, 1.1 to 10 equivalents) and stirred in a solvent such as tetrahydrofuran, dioxane, dimethoxyethane, N, N-dimethylformamide, dimethyl sulfoxide, xylene, toluene, triethylamine at 30 to 200 ° C. for 1 to 60 hours. how to.

[C] Two or more substituted fluorides (F—Ar—F) having a partial structure in which five benzene rings or five pyridine rings connected at the m-position are connected are used as a starting material. A product obtained by reacting a primary amine (Ar ¹¹ Ar ¹² NH) with a strong base such as sodium hydride, tert-butoxypotassium, or n-butyllithium (about 1.1 to 10 equivalents relative to the starting fluorine atom) Is stirred in a solution of tetrahydrofuran, dioxane, ether, N, N-dimethylformamide and the like under heating and reflux for 1 to 60 hours.

In the methods [A] and [B], the starting material was esterified such as —OSO ₂ CF ₃ , —OSO ₂ C ₆ H ₄ CH ₃ instead of the halide (X—Ar—X). A compound containing two or more hydroxyl groups (for example, CF ₃ SO ₂ O—Ar—OSO ₂ CF ₃ ) can also be used.

  Further, an asymmetric compound can be synthesized by reacting the methods [A] to [C] stepwise as in the following formula.

  Two or more substituted halides having a partial structure in which five benzene rings or five pyridine rings linked at the m-position as starting materials are linked 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 "Organic synthesis to open up its various reaction modes and latest results" (1997, Kenjiro, Kagaku Dojinsha), "Under Borhard Shore Modern Organic Chemistry" (2004, KPCVollhardt, Kagaku Dojinsha)) Ring-to-ring coupling reactions such as the cited coupling reactions of aryl halides and aryl borates can be used.

  In addition, after synthesizing an aryl halide having a triarylamine structure, it is possible to form a structure in which five benzene rings or pyridine rings linked at the m-position are linked.

  As a purification method of the compound represented by the above general formula (I) synthesized in this way, “Separation and Purification Technology Handbook” (1993, edited by The Chemical Society of Japan), “Minor components by chemical conversion method” And “Advanced Separation of Difficulty Substances” (1988, issued by IPC Corporation) or “Separation and Purification” of “Experimental Chemistry Course (4th Edition) 1” (1990, edited by The Chemical Society of Japan) In addition to the method described in the section, known techniques can be used.

  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.

[Composition for organic electroluminescence device]
The composition for organic electroluminescent elements of the present invention contains the charge transport material of the present invention, and more preferably further contains a solvent and a phosphorescent material.

[1] Solvent The composition for organic electroluminescent elements of the present invention preferably contains a solvent.
The solvent contained in the composition for an organic electroluminescent device of the present invention is not particularly limited as long as the charge transporting material of the present invention, which is a solute, dissolves well.

  Since the charge transport material of the present invention has very 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, ethyl benzoate, 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 Alcohol having an alicyclic ring such as cyclohexanol and cyclooctanol; Aliphatic alcohol such as butanol and hexanol; Aliphatic ether such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and propylene glycol-1-monomethyl ether acetate (PGMEA); Acetic acid Aliphatic esters such as ethyl, 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 organic electroluminescent elements 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 in film formation stability due to solvent evaporation from the composition during wet film formation, the boiling point is 100 ° C. or higher, preferably 150 ° C. as a solvent for the composition for organic electroluminescent elements. It is effective to use a solvent having a boiling point of 200 ° C. or higher, more preferably 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-mentioned conditions, ie, solute solubility, evaporation rate, and water solubility conditions, may be used alone. However, if a solvent that satisfies all the conditions cannot be selected, two or more solvents may be mixed. It can also be used.

[2] Luminescent Material The composition for organic electroluminescent elements of the present invention preferably contains a luminescent material.

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

  Any known material can be applied as the light-emitting material, and a fluorescent light-emitting material or a phosphorescent light-emitting material can be used singly or as a mixture of a plurality of materials. From the viewpoint of internal quantum efficiency, a phosphorescent light-emitting material is preferable.

  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は炭素又は窒素を表す。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及び^Ｒ９５は無い。）

(In the general formula (VI), ^{M d} represents a metal, T is ^.R 92 ^{to R 95} that represents a carbon or nitrogen, each independently represent a substituent. However, when T is ^{nitrogen, R 94} and ^There is no ^R95 .)

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 preferred 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又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又は２を表す。更に、環Ａ１及び環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又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及び環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 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. Furthermore, 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 general formulas (Va), (Vb), and (Vc), the group of the ring A1 and the ring A1 ′ is preferably a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a thienyl group, a furyl group, a benzo group, for example. 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 for ring A1, ring A1 ′, ring A2 and ring A2 ′, an alkyl group, alkoxy group, aromatic hydrocarbon group, cyano group, halogen atom, haloalkyl group, diarylamino group, carbazolyl group are more preferable. 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, compounds having an arbitrary substituent bonded thereto, and compounds formed by condensing an arbitrary group 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, R ⁹⁴ and R ⁹⁵ are absent.

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 connected 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 organic electroluminescent elements of the present invention, various other solvents may be contained as necessary in addition to the solvent and the light emitting material described above. 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 the composition for organic electroluminescent elements Solid content such as charge transport materials, luminescent materials and components (leveling agents, etc.) that can be added as necessary in the composition for organic electroluminescent elements The concentration 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% by weight or more, Usually, it is 80% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, still more preferably 30% by weight or less, and most preferably 20% by weight or less. When this concentration is less than 0.01% by weight, it is difficult to form a thick film when forming a thin film, and when it exceeds 80% by weight, it is difficult to form a thin film.

  In the composition for organic electroluminescent elements of the present invention, the weight mixing ratio of the light emitting material / charge transporting material is usually 0.1 / 99.9 or more, more preferably 0.5 / 99.5 or more. More preferably, it is 1/99 or more, most preferably 2/98 or more, usually 50/50 or less, more preferably 40/60 or less, and further preferably 30/70 or less. Most preferably, it is 20/80 or less. If this ratio is less than 0.1 / 99.9 or exceeds 50/50, the light emission efficiency is significantly reduced.

[5] Preparation method of composition for organic electroluminescence device The composition for organic electroluminescence device of the present invention is a charge transport material, a luminescent material, and various additions such as a leveling agent and an antifoaming agent that can be added as necessary. It is prepared by dissolving a solute comprising an agent in a suitable 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 organic electroluminescent elements
When an organic electroluminescent element is produced by forming a layer by a wet film forming method using the composition for organic electroluminescent elements, if water is present in the composition for organic electroluminescent elements to be used, moisture is formed in the formed film. Since it mixes and the uniformity of a film | membrane is impaired, the one where the water content in the composition for organic electroluminescent elements is as little as possible is preferable. 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 organic electroluminescent devices, moisture remains in the dried film. However, there is a possibility of deteriorating the characteristics of the element, which is not preferable.

  Specifically, the amount of water contained in the composition for organic electroluminescent elements of the present invention is usually 1% by weight or less, preferably 0.1% by weight or less, more preferably 0.01% by weight or less.

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

(Uniformity)
The composition for organic electroluminescent elements of the present invention is preferably in a uniform liquid state at room temperature in order to enhance stability in a wet film forming process, for example, ejection stability from a nozzle in an ink jet film forming method. . 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 composition for organic electroluminescent elements of the present invention, in the case of extremely low viscosity, for example, coating surface non-uniformity due to excessive liquid film flow in the film forming process, nozzle ejection failure in ink jet film formation, etc. are likely to occur. In the case of extremely high viscosity, nozzle clogging or the like in ink jet film formation tends 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 organic electroluminescent elements of the present invention is high, the wettability of the liquid for film formation with respect to the substrate is lowered, the leveling property of the liquid film is poor, and the film formation surface is disturbed during drying. Since the problem of becoming easy occurs, 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 organic electroluminescent elements of the present invention is high, problems such as changes in solute concentration due to evaporation of the solvent tend to 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 Organic Electroluminescence Device The composition for organic electroluminescence device of the present invention is filled in a container capable of preventing the transmission of ultraviolet rays, for example, a brown glass bottle, and sealed and stored. Is preferred. 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 a layer containing the charge transport material of the present invention represented by the general formula (I).

  FIG. 1 is a schematic cross-sectional view showing an example of the structure of a general organic electroluminescence device used in the present invention. 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a light emitting layer, and 5 is an electron. The injection layer 6 represents the 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, if necessary, the hole injection layer 3 may contain a binder resin that hardly traps charges or a coating property improving agent.

  However, as the hole injection layer 3, only the electron-accepting compound is formed on the anode 2 by a wet film forming method, and the organic electroluminescent element composition of the present invention is directly applied and laminated thereon. Is possible. In this case, when a part of the composition for organic electroluminescent elements of the present invention interacts with the electron accepting compound, a layer excellent in hole injecting property 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、又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、又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 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、又は置換基を有していてもよい芳香族複素環由来の１価又は２価の基を表す。Ｒ^３１及びＲ^３２は、各々独立して、水素原子又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 ³¹ and R ³² each independently represents a hydrogen atom or an arbitrary 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 or more types 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 Z.

[Substituent group Z]
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 usually 2 or more, usually 11 or less, preferably 5 or less, 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 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 ³¹ and R ³² , 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 substituent group Z.

  Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the general formula (VII) include those described in WO 2005/089024, and suitable examples thereof are also the same. Although the compound (PB-1) represented by a formula is mentioned, it is not limited to them at all.

  Preferable examples of 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及び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、又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及び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、又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^４１〜Ｒ^４３は各々独立して、水素原子又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. 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, among Ar ^{45 to} Ar ⁴⁸ , two groups bonded to the same N atom may be bonded to each other to form a ring, and R ^{41 to} R ⁴³ are independent of each other. 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 to Ar respectively. Same as Ar ²⁵ . R ^{41 to} R ⁴³ are preferably a hydrogen atom or a substituent described in [Substituent group Z], 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 WO 2005/089024, and preferred examples thereof are also the same. However, it is not limited to them.

  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′- (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), lid Cyanine 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.

  In addition, preferred specific examples of the polythiophene derivative applicable as the hole transporting compound in the present invention include poly (3,4-ethithenedioxythiophene) (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 and 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 the compounds alone, or may contain two or more. In the case of containing two or more kinds of hole transporting compounds, the combination is arbitrary, but one or more kinds of aromatic tertiary amine polymer compounds and one or two kinds of other hole transporting compounds. 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 still 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 the onium salt substituted with an organic group, cyano compound, and aromatic boron compound suitable as an electron-accepting compound include those described in WO 2005/089024, and the preferred examples thereof are also the same. Although the compound (A-2) represented by 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 above-described 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. Further, it is more preferable in terms 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 produced by oxidative polymerization (dehydrogenation polymerization), that is, by oxidizing the 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 a wet film-forming method, a predetermined amount of one or more of the aforementioned materials (hole transporting compound, electron accepting compound, cation radical compound) is not trapped as 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 deactivating substance or deactivating 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 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 may be used in any combination and ratio. Moreover, you may use 1 type, or 2 or more types among these solvents in combination with 1 type or 2 or more types among the above-mentioned ether type solvent and ester type 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 are therefore preferably used in a mixture 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 The 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. A layer formed by a wet film forming method using the composition for a light emitting element is particularly preferable.

  Here, specific examples of the wet film forming method include spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, and inkjet method.

  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, CsCO ₃ may be inserted at the interface between the cathode 6 and the organic light emitting layer 4 or the electron transport layer 8 described later. This is an effective method for improving the efficiency of the device (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 coating method or a vacuum deposition method in the same manner as the light emitting layer 4. In the case of the vacuum vapor deposition method, the vapor deposition source is put in 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 Evaporate by heating 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 injecting / transporting layer on the substrate placed facing the crucible and the 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 (such as the electron injection layer 5 or the organic light emitting layer 4) on the organic light emitting layer side. 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 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 made centering on the element having the layer structure 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 the electron transporting 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 organic light emitting layer 4 by a coating method or a vacuum deposition method in the same manner as the hole injection layer 3. Usually, a vacuum deposition method is used.

  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 serves to block holes moving from the anode 2 from reaching the cathode 6 and to efficiently transport electrons injected from the cathode 6 toward the organic light emitting layer 4. By the compound that can be formed, the light emitting layer 4 is laminated on the light emitting layer 4 so as to be in contact with the interface 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).

  Further, 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) Stack of hole blocking layer / electron transport layer, 4) There are usages such as not using.

  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 organic 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 organic light emitting layer 4, the hole injection layer 3, and the anode 2 can be laminated on the substrate 1 in this order. Thus, it is also possible to provide the organic electroluminescence device of the present invention between two substrates, at least one of which is highly transparent. Similarly, it is also possible to laminate | stack to the structure opposite to the said each layer structure shown in FIGS.

Furthermore, it is possible to adopt 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). 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]
The synthesis example of the compound used for the charge transport material of the present invention is shown below.
In the following synthesis 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.

(Synthesis Example 1: Synthesis of Compound (I-1) According to the Present Invention Represented by General Formula (I))

  In air, 3′-bromoacetophenone (25.0 g), benzaldehyde (6.66 g), ammonium acetate (62.0 g), and acetic acid (157 ml) were stirred with heating under reflux for 9 hours and allowed to cool to room temperature. . The precipitated crystals were collected by filtration, washed twice with ethanol, and dried under reduced pressure to give 2,6-bis (3-bromophenyl) -4-phenylpyridine (6.72 g, yield) as the target compound 1. 23%) was obtained as white crystals.

  In a nitrogen stream, carbazole (7.00 g), 3-bromoiodobenzene (14.2 g), copper powder (2.66 g), potassium carbonate (5.79 g), and tetraglyme (10 ml) were heated to 140 ° C. The mixture was stirred for 5 hours and allowed to cool to room temperature. After completion of the reaction, chloroform was added to the reaction solution, and insoluble matters were separated by filtration. Chloroform contained in the filtrate was distilled off under reduced pressure and purified by silica gel column chromatography. The target product 2 (10.5 g, yield 78%) was obtained as a colorless viscous liquid by drying under reduced pressure.

  In a nitrogen stream, the target compound 2 (10.5 g), bis (pinacolatodiboron) (9.93 g), potassium acetate (10.9 g), and anhydrous dimethyl sulfoxide (190 ml) were heated to 60 ° C. under the conditions of 15 The mixture was stirred for 1 minute, [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium (II) dichloromethane complex (0.799 g) was added, and the mixture was stirred for 9 hours while heating at 80 ° C. After allowing to cool to room temperature, water (250 ml) and toluene (500 ml) were added to the reaction solution and stirred. The aqueous layer was re-extracted twice with toluene, the organic layers were combined, and magnesium sulfate and activated clay were added. Magnesium sulfate and activated clay were separated by filtration, and toluene was distilled off under reduced pressure. The precipitated crystals were washed with cold methanol and dried under reduced pressure to obtain target product 3 (9.86 g, yield 80%) as white crystals.

In a nitrogen stream, a mixture of target 1 (1.86 g), target 3 (3.84 g), dimethoxyethane (80 ml) and water (12 ml) was added to tetrakis (triphenylphosphine) palladium (0.37 g). Potassium carbonate (3.32 g) was sequentially added, and the mixture was stirred for 6 hours under reflux with heating. To the resulting solution was added brine (100 ml), extracted with dichloromethane (2 × 100 ml), added anhydrous magnesium sulfate and activated clay to the organic layer, stirred, filtered and concentrated to obtain a solid. The fraction was purified by silica gel column chromatography to obtain the desired product 4 (present compound (I-1)) (2.16 g).
DEI-MS (m / z = 789 (M ⁺ ))
The vaporization temperature of this product was 541 ° C., the melting point was not detected, and the glass transition temperature was 125 ° C.

(Synthesis Example 2: Synthesis of Compound (I-2) According to the Present Invention Represented by Formula (I))

  To a mixture of 1,3-diiodobenzene (14.9 g), 3-bromophenylboronic acid (20.0 g), toluene (200 ml), and ethanol (50 ml) in a nitrogen stream, sodium carbonate (24.0 g) Solution (100 ml) and tetrakis (triphenylphosphine) palladium (2.00 g) were sequentially added, and the mixture was stirred for 7 hours while heating under reflux. After adding water (200 ml) and toluene (100 ml) to the resulting solution, the aqueous layer was extracted with toluene (2 × 100 ml), the organic layers were combined, anhydrous magnesium sulfate and activated clay were added, and the mixture was stirred. The solid obtained by filtration and concentration was purified by silica gel column chromatography to obtain the intended product 5 (15.5 g).

  An aqueous solution of sodium carbonate (11.2 g) in a mixture of the target compound 5 (8.19 g), 2,5-difluorophenylboronic acid (10.0 g), toluene (150 ml), and ethanol (25 ml) in a nitrogen stream. (75 ml) and tetrakis (triphenylphosphine) palladium (0.975 g) were sequentially added, and the mixture was stirred for 8 hours while heating under reflux. After adding water (150 ml) and toluene (100 ml) to the obtained solution, the aqueous layer was extracted with toluene (2 × 100 ml), the organic layers were combined, anhydrous magnesium sulfate and activated clay were added, and the mixture was stirred. The solid obtained by filtration and concentration was purified by silica gel column chromatography to obtain the intended product 6 (7.91 g).

Carbazole (17.7 g) was added to a suspension of sodium hydride (55%, 4.61 g) in anhydrous N, N-dimethylformamide (100 ml) in a nitrogen stream, and the mixture was stirred at 80 ° C. for 30 minutes. Product 6 (6.00 g) was added, and the mixture was stirred with heating under reflux for 8 hr. Under ice cooling, water (50 ml) and methanol (300 ml) were added thereto, and the deposited precipitate was separated by filtration and washed with methanol. The obtained solid content was purified by silica gel column chromatography to obtain the intended product 7 (present compound (I-2)) (1.02 g).
DEI-MS (m / z = 1042 (M ⁺ ))
The vaporization temperature of this product was 554 ° C., the melting point was not detected, and the glass transition temperature was 169 ° C.

(Synthesis Example 3: Synthesis of Compound (I-3) According to the Present Invention Represented by Formula (I))

  While cooling with an ethanol bath at −60 to −65 ° C. in a nitrogen stream, a solution of target 2 (9.06 g) in anhydrous tetrahydrofuran (400 ml) was added with a normal hexane solution of 1.54 M normal butyl lithium (27.4 ml). Was added dropwise over 7 minutes, followed by stirring for 40 minutes. Thereafter, the mixture was stirred at room temperature for 2.2 hours, 1N aqueous hydrochloric acid solution (45 ml) was added, and the mixture was further stirred for 30 minutes. Tetrahydrofuran was distilled off from the resulting solution under reduced pressure, diethyl ether (400 ml) and saturated brine (100 ml) were added and shaken, and the organic layer was separated and washed with saturated brine. It was. Anhydrous magnesium sulfate and activated clay were added to the obtained organic layer, stirred, filtered and concentrated. The obtained solid was suspended and washed with water and normal hexane, and then purified by reprecipitation from ethanol-normal hexane to obtain the desired product 8 (4.03 g).

  To a 200 ml four-necked flask, 3'-bromoacetophenone (11.9 g) and dehydrated ethanol were added under nitrogen, and tetrachlorosilane (20.3 g) was further added dropwise. After stirring for 6 hours at room temperature, the mixture was poured into ice and the precipitated solid was collected by filtration. The filtered product was dissolved in toluene, the insoluble matter was removed, and recrystallization was performed with a mixed solvent of ethanol and toluene. As a result, white needle crystals (6.4 g) of the target product 9 were obtained.

To a 200 ml three-necked flask, target product 9 (1.2 g), target product 8 (2.5 g), toluene (66 mL), water (10 mL), and potassium carbonate (2.7 g) are added, and the system is filled with nitrogen. After the substitution, tetrakis (triphenylphosphine) palladium (0) (228 mg) was added, and the mixture was stirred at a bath temperature of 100 ° C. for 6 hours. The insoluble material was collected by filtration, washed with heat with pyridine and methanol, and purified by sublimation. As a result, a yellow glassy solid (1.5 g) of the target product 10 (present compound (I-3)) was obtained.
DEI-MS (m / z = 1031 (M ⁺ ))
The glass transition temperature of this product was 150 ° C., no melting point was observed, and the vaporization temperature was 573 ° C.

(Synthesis Example 4: Synthesis of Compound (I-4) Represented by General Formula (I) According to the Present Invention)

  3'-bromoacetophenone (25 g), 4-phenylbenzaldehyde (13 g), ammonium acetate (64.4 g), and acetic acid (165 ml) were stirred with heating under reflux for 9 hours and allowed to cool to room temperature. The precipitated crystals were collected by filtration, heated and washed twice with ethanol, and dried under reduced pressure to obtain target compound 11 (7.483 g, yield 21.2%) as white crystals.

To a mixture of the target product 11 (8.0 g), the target product 8 (13.56 g), ethanol (17 ml), and toluene (170 ml) heated to 60 ° C. in a nitrogen atmosphere, sodium carbonate (7.79 g) and An aqueous solution of water (50 ml) was added, tetrakis (triphenylphosphine) palladium (0.68 g) was further added, and the mixture was stirred at 80 ° C. for 10 hours under a nitrogen atmosphere. After allowing to cool to room temperature, the organic layer was extracted, concentrated, and reprecipitated in methanol to obtain crystals. This was purified by silica gel column chromatography (toluene / hexane = 1/1). Further, the product was washed with methanol and ethyl acetate and dried under reduced pressure to obtain the target compound 12 (present compound (I-4)) (7.8 g, yield 62%) as white crystals. When 7.8 g of this white crystal was purified by sublimation, 6.2 g of a white solid was recovered.
From DEI-MS (m / z = 866 (M ⁺ )), it was confirmed to be the target product 12.
The vaporization temperature of this product was 558 ° C., the melting point was not observed, and the glass transition temperature was 133 ° C.

Synthesis Example 5 Synthesis of Compound (I-5) According to the Present Invention Represented by Formula (I)

Under a nitrogen atmosphere, a 2M sodium carbonate aqueous solution (20 ml) was added to a solution of the target product 5 (1.9 g, 5.0 mmol) and the target product 8 (4.3 g, 15.0 mmol) in dimethoxyethane (40 ml). Bubbling was performed for 15 minutes and tetrakistriphenylphosphine palladium (0) (288 mg, 0.25 mmol) was added in one portion. The reaction mixture was stirred at reflux for 12 hours, allowed to cool to room temperature, poured into water and extracted with dichloromethane (2 × 50 ml). The organic layer was washed with a saturated aqueous sodium chloride solution (50 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the intended product 13 (the present compound (I-5)) (2.5 g).
When this was subjected to mass spectrometry, the molecular ion peak was 712 (M ⁺ ).
The melting point of this product was not observed, and the glass transition temperature was 112 ° C.

(Synthesis Example 6: Synthesis of Compound (I-6) According to the Present Invention Represented by Formula (I))

  Under a nitrogen atmosphere, 2M sodium carbonate aqueous solution (194 ml) was added to a dimethoxyethane (234 ml) solution of dibromocarbazole (25.2 g, 77.6 mmol) and phenylboronic acid (37.8 g, 310 mmol), and nitrogen bubbling was further performed for 15 minutes. And tetrakistriphenylphosphine palladium (0) (4.5 g, 310 mmol) was added in one portion. The reaction mixture was stirred at 80 ° C. for 7 hours, allowed to cool to room temperature, poured into water, and extracted with dichloromethane (2 × 200 ml). The organic layer was washed with a saturated aqueous sodium chloride solution (2 × 100 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the intended product 14 (10.37 g).

  55% sodium hydride (0.819 g, 18.8 mmol) dispersed in oil was suspended in dry dimethylformamide (86 ml) and diphenylcarbazole (5.00 g, 15.7 mmol) was added in small portions. The mixture was warmed to 80 ° C. and 3-bromofluorobenzene (11.0 g, 62.6 mmol) was added dropwise. After the dropwise addition, the solution was stirred for 5 and a half hours while refluxing. The reaction mixture was poured into ice water, and the precipitated solid was collected by filtration. The obtained solid was purified by recrystallization to obtain the target product 15 (4.33 g, 58%).

  Under a nitrogen atmosphere, 3,6-diphenyl-9- (3-bromophenyl) carbazole (4.31 g, 9.08 mmol), bispinacolatodiboron (2.77 g, 10.9 mmol), and potassium acetate (3. [1,1′-bis (diphenylphosphino) ferrocene] dichloropalladium (II) complex dichloromethane adduct (0.22 g, 0.27 mmol) was added to a dimethyl sulfoxide solution (45 ml) of 03 g, 30.87 mmol). Stir at 80 ° C. for 8 hours and pour the reaction mixture into water. The mixture was extracted with toluene (2 × 300 ml), dried over anhydrous magnesium sulfate, concentrated under reduced pressure, filtered with activated clay. The solvent of the filtrate was distilled off under reduced pressure, and the residue was recrystallized to obtain the target product 16 (3.27 g, 69%).

Under a nitrogen atmosphere, 2M sodium carbonate aqueous solution (15 ml) was added to a solution of target product 5 (1.0 g, 2.6 mmol) and target product 16 (3.22 g, 6.17 mmol) in dimethoxyethane (30 ml). Bubbling was performed for 15 minutes and tetrakistriphenylphosphine palladium (0) (144 mg, 0.13 mmol) was added in one portion. The reaction mixture was stirred at reflux for 12 hours, allowed to cool to room temperature, poured into water and extracted with dichloromethane (2 × 50 ml). The organic layer was washed with a saturated aqueous sodium chloride solution (50 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the intended product 17 (the present compound (I-6)) (1.7 g).
When this was subjected to mass spectrometry, the molecular ion peak was 1016 (M ⁺ ).
The melting point of this product was not observed, and the glass transition temperature was 163 ° C.

(Synthesis Example 7: Synthesis of Compound (I-7) According to the Present Invention Represented by Formula (I))

Under a nitrogen atmosphere, 2M aqueous potassium carbonate solution (10 ml) was added to a solution of the target product 11 (1.51 g, 2.8 mmol) and the target product 16 (3.8 g, 7.3 mmol) in toluene (30 ml) -ethanol (7.5 ml). And nitrogen bubbling was performed for 15 minutes, and tetrakistriphenylphosphine palladium (0) (0.26 g, 0.224 mmol) was added at once. The reaction mixture was stirred at reflux for 3.5 hours, allowed to cool to room temperature, poured into water and extracted with toluene (3 × 50 ml). The organic layer was washed with a saturated aqueous sodium chloride solution (2 × 50 ml), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the intended product 18 (the present compound (I-7)) (3.2 g).
When this was subjected to mass spectrometry, the molecular ion peak was 1169 (M ⁺ ).
The vaporization temperature of this product was 581 ° C., the melting point was not observed, and the glass transition temperature was 181 ° C.

[Measurement of solubility in toluene]
(Measurement Example 1: Solubility Measurement of Compound (I-1) of the Present Invention)
The solubility of the present compound (I-1) in toluene was examined. The results are shown in Table 1. As shown in Table 1, the compound (I-1) of the present invention showed high solubility in toluene.

(Measurement Example 2: Solubility Measurement of Compound (I-2) of the Present Invention)
The solubility of the present compound (I-2) in toluene was examined. The results are shown in Table 1. As shown in Table 1, the compound (I-2) of the present invention showed high solubility in toluene.

(Measurement Example 3: Solubility Measurement of Compound (I-4) of the Present Invention)
The solubility of the present compound (I-4) in toluene was examined. The results are shown in Table 1. As shown in Table 1, the compound (I-4) of the present invention showed high solubility in toluene.

(Measurement Example 4: Solubility Measurement of the Compound (I-7) of the Present Invention)
The solubility of the compound (I-7) of the present invention in toluene was examined. The results are shown in Table 1. As shown in Table 1, the compound (I-7) of the present invention showed high solubility in toluene.

(Measurement Example 5: Measurement of solubility of comparative compound (H-1))
The solubility of the compound H-1 represented by the following structural formula in toluene was examined. The results are shown in Table 1. As shown in Table 1, the solubility of Compound H-1 in toluene was low.

(Measurement Example 6: Measurement of solubility of comparative compound (H-6))
The solubility in toluene of the compound H-6 represented by the following structural formula was examined. The results are shown in Table 1. As shown in Table 1, the solubility of Compound H-6 in toluene was relatively low.

(Measurement Example 7: Solubility Measurement of Comparative Compound (H-7))
The solubility in toluene of the compound H-7 represented by the following structural formula was examined. The results are shown in Table 1. As shown in Table 1, the solubility of Compound H-7 in toluene was low.

(Measurement Example 8: Measurement of solubility of comparative compound (H-8))
The solubility in toluene of the compound H-8 represented by the following structural formula was examined. The results are shown in Table 1. As shown in Table 1, the solubility of Compound H-8 in toluene was low.

(Measurement Example 9: Measurement of solubility of comparative compound (H-9))
The solubility in toluene of the compound H-9 represented by the following structural formula was examined. The results are shown in Table 1. As shown in Table 1, the solubility of Compound H-9 in toluene was low.

[Manufacture and evaluation of organic electroluminescence devices]
Example 1
An organic electroluminescent element having the structure shown in FIG. 3 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 having a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is patterned into a 2 mm wide stripe using normal photolithography and hydrochloric acid etching. Thus, an anode 2 was formed. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  Next, the hole injection layer 3 was formed by a wet film forming method as follows. As a material of the hole injection layer 3, a polymer compound having an aromatic amino group having the following structural formula (PB-1 (weight average molecular weight: 29400, number average molecular weight: 12600)) and an electron having the structural formula shown below. Using the receptor compound (A-2), spin coating was performed under the following conditions.

Spin coating conditions Solvent Ethyl benzoate Coating solution concentration PB-1 2.0% by weight
A-2 0.4% by weight
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 230 ° C. × 15 minutes A uniform thin film having a thickness of 30 nm was formed by the above spin coating.

  Then, the light emitting layer 4 was formed by the wet film forming method as follows. As the material for the light-emitting layer 4, the compound (I-1) of the present invention is used together with an aromatic amine compound (H-10) having the structural formula shown below and an iridium complex (D-2) having the structural formula shown below. It spin-coated on the conditions of this.

Spin coating conditions Solvent Toluene Coating solution concentration I-1 1.0% by weight
H-12 1.0% by weight
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 60 seconds Drying conditions 80 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 80 nm was formed by the above spin coating.

Next, a pyridine derivative (HB-1) shown below as the hole blocking layer 8 was laminated at a crucible temperature of 242 to 258 ° C. with a deposition rate of 0.08 nm / second and a film thickness of 5 nm. The degree of vacuum during vapor deposition was 5.2 × 10 ⁻⁴ Pa (about 4.0 × 10 ⁻⁶ Torr).

Next, an aluminum 8-hydroxyquinoline complex (ET-1) shown below was deposited as an electron transport layer 7 on the hole blocking layer 8 in the same manner. At this time, the crucible temperature of the aluminum 8-hydroxyquinoline complex is controlled in the range of 216 to 231 ° C., and the degree of vacuum during the deposition is 4.0 × 10 ⁻⁴ Pa (about 3.2 × 10 ⁻⁶ Torr), The deposition rate was 0.1 nm / second and the film thickness was 30 nm.

The substrate temperature during vacuum deposition of 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 was installed in another vacuum deposition apparatus, and the degree of vacuum in the apparatus was 2.2 × 10 ⁻⁶ Torr (about 2.8 × 10 ⁻⁴ Pa) in the same manner as the organic layer. ) Exhaust until below.

Next, on the electron transport layer 7, lithium fluoride (LiF) is used as the electron injection layer 5, using a molybdenum boat, a deposition rate of 0.03 nm / second, a degree of vacuum of 2.7 × 10 ⁻⁶ Torr ( The film was formed on the electron transport layer 7 with a film thickness of 0.5 nm at about 3.5 × 10 ⁻⁴ Pa).

Next, on the electron injection layer 5, as the cathode 6, aluminum was heated by a molybdenum boat, deposition rate 0.3 nm / sec, the vacuum degree 4.3 × ¹⁰ -6 Torr (about 5.6 × 10 ^{- The} cathode 6 was completed by forming an aluminum layer with a thickness of 80 nm at ⁴ Pa).
The substrate temperature at the time of vapor deposition of the electron injection layer 5 and the 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 element are as follows.
Luminance / current: 27.8 [cd / A] @ 100 cd / m ²
Voltage: 6.2 [V] @ 100 cd / m ²
Luminous efficiency: 14.2 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 513 nm, which was identified as that from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.30, 0.63).

(Example 2)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the present compound (I-2) was used instead of the present compound (I-1).

That is, the compound of the present invention (I-2) is used as a material for the light-emitting layer 4 together with the aromatic amine compound (H-10) and the iridium complex (D-2) described above, and the following spin coating is performed by a wet film forming method. Formed under conditions.
Spin coating conditions Solvent Toluene Coating solution concentration I-2 1.0% by weight
H-10 1.0 wt%
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 60 seconds Drying conditions 80 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 80 nm was formed by the above spin coating.
The light emission characteristics of this element are as follows.
Luminance / current: 31.9 [cd / A] @ 100 cd / m ²
Voltage: 9.0 [V] @ 100 cd / m ²
Luminous efficiency: 11.1 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 510 nm, which was identified as from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.29, 0.63).

(Example 3)
An organic electroluminescent element having the structure shown in FIG. 3 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate 1 having a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is patterned into a 2 mm wide stripe using normal photolithography and hydrochloric acid etching. Thus, an anode 2 was formed. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  Next, the hole injection layer 3 was formed by a wet film forming method as follows. As a material for the hole injection layer 3, a polymer compound having an aromatic amino group having the following structural formula (PB-2 (weight average molecular weight: 26500, number average molecular weight: 12000)) and an electron having the structural formula shown below. Using the receptor compound (A-2), spin coating was performed under the following conditions.

Spin coating conditions Solvent Ethyl benzoate Coating solution concentration PB-2 2.0% by weight
A-2 0.4% by weight
Spinner speed 2000rpm
Spinner rotation time 30 seconds Drying conditions 230 ° C. × 3 hours A uniform thin film having a thickness of 30 nm was formed by the above spin coating.

  Then, the light emitting layer 4 was formed by the wet film forming method as follows. The compound (I-1) of the present invention was used as a material for the light emitting layer 4 together with the iridium complex (D-2) used in Example 1, and spin-coated under the following conditions.

Spin coating conditions Solvent Xylene Coating concentration I-1 2.0% by weight
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 130 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 40 nm was formed by the above spin coating.

Next, as the hole blocking layer 8, the pyridine derivative (HB-1) used in Example 1 was laminated at a crucible temperature of 280 to 280 ° C. with a deposition rate of 0.1 to 0.13 nm / second and a film thickness of 5 nm. did. The degree of vacuum at the time of vapor deposition was 2.9 × 10 ⁻⁴ Pa.

Next, the aluminum 8-hydroxyquinoline complex (ET-1) used in Example 1 was deposited on the hole blocking layer 8 in the same manner as the electron transport layer 7. The crucible temperature of the aluminum 8-hydroxyquinoline complex at this time is controlled in the range of 383 to 364 ° C., the degree of vacuum during the deposition is 2.7 × 10 ⁻⁴ Pa, and the deposition rate is 0.1 to 0.13 nm / The film thickness was 30 nm in seconds.

The substrate temperature during vacuum deposition of 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. The device was in close contact with each other so as to be orthogonal to each other, placed in another vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus was 2.3 × 10 ⁻⁵ Pa or less in the same manner as the organic layer.

Next, as the electron injection layer 5, first, lithium fluoride (LiF) was deposited using a molybdenum boat at a deposition rate of 0.008 to 0.01 nm / second and a degree of vacuum of 4.0 × 10 ⁻⁵ Pa. A film having a thickness of 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 thickness of 80 nm was deposited on the electron injection layer 5 at a deposition rate of 0.08 to 0.12 nm / second and a degree of vacuum of 9.5 × 10 ⁻⁵ Pa. Thus, the cathode 8 was completed.
The substrate temperature at the time of vapor deposition of the above two-layer cathode 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 element are as follows.
Luminance / current: 8.4 [cd / A] @ 100 cd / m ²
Voltage: 9.7 [V] @ 100 cd / m ²
Luminous efficiency: 2.7 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 512.8 nm, which was identified as that from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.311, 0.622).

Example 4
An organic electroluminescent element was produced in the same manner as in Example 3 except that the present compound (I-2) was used in place of the present compound (I-1).

That is, the present compound (I-2) was used as a material for the light emitting layer 4 together with the iridium complex (D-2), and the light emitting layer 4 was formed by the wet film forming method under the following spin coating conditions.
Spin coating conditions Solvent Xylene Coating solution concentration I-2 2.0% by weight
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 130 ° C x 60 minutes (under reduced pressure)

The light emission characteristics of this element are as follows.
Luminance / current: 13.9 [cd / A] @ 100 cd / m ²
Voltage: 9.1 [V] @ 100 cd / m ²
Luminous efficiency: 4.8 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 514.0 nm, which was identified as that from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.311, 0.624).

(Example 5)
An organic electroluminescent element was produced in the same manner as in Example 3 except that the present compound (I-4) was used instead of the present compound (I-1).

That is, using the compound (I-4) of the present invention together with the iridium complex (D-2) as a material for the light emitting layer 4, the light emitting layer 4 was formed by the wet film forming method under the following spin coating conditions.
Spin coating conditions Solvent Xylene Coating concentration I-4 2.0% by weight
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 130 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 40 nm was formed by the above spin coating.

The light emission characteristics of this element are as follows.
Luminance / current: 10.8 [cd / A] @ 100 cd / m ²
Voltage: 8.8 [V] @ 100 cd / m ²
Luminous efficiency: 3.9 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 514.0 nm, which was identified as that from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.306, 0.626).

(Example 6)
An organic electroluminescent element was produced in the same manner as in Example 3 except that the present compound (I-7) was used instead of the present compound (I-1).

That is, the present compound (I-7) was used together with the iridium complex (D-2) as a material for the light emitting layer 4, and the light emitting layer 4 was formed by the wet film forming method under the following spin coating conditions.
Spin coating conditions Solvent Xylene Coating solution concentration I-7 2.0% by weight
D-2 0.1% by weight
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 130 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 40 nm was formed by the above spin coating.

The light emission characteristics of this element are as follows.
Luminance / current: 14.4 [cd / A] @ 100 cd / m ²
Voltage: 7.9 [V] @ 100 cd / m ²
Luminous efficiency: 5.7 [1 m / w] @ 100 cd / m ²

  The maximum wavelength of the emission spectrum of the device was 516.4 nm, which was identified as from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.335, 0.611).

  As is clear from the above examples, the organic electroluminescence device using the charge transport material of the present invention as a host material is uniform because the charge transport material of the present invention has excellent charge transport properties and does not easily crystallize. Light emission was obtained, the light emission efficiency was high, and the device could be driven at a low voltage.

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.

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

Claims (9)

A charge transport material represented by the following general formula (I):

(In general formula (I), each of ring A to ring E independently represents a benzene ring which may have a substituent, or a pyridine ring which may have a substituent. Two or more of the rings E are not pyridine rings.
Ar ^{1 to} Ar ⁴ each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Ar ¹ and Ar ² , Ar ¹ and Q ¹ have substituents, Ar ³ and Ar ⁴ , Ar ³ and Q ² have substituents which are bonded to each other and each independently has a substituent. An optional ring may be formed.
Q ¹ and Q ² each independently have an aromatic hydrocarbon ring that may have a substituent, or a substituent that connects any one of ring A to ring E to a nitrogen atom. Represents a divalent linking group derived from an aromatic heterocycle or a direct bond. However, Q < ¹ >, Q < ² > ^couple | bonds with a ring which is different among ring A-ring E, respectively. ) The charge transport material according to claim 1, which is represented by the following general formula (II).

(In General Formula (II), Ring A to Ring E and Ar ^{1 to} Ar ⁴ have the same meanings as in General Formula (I).
Q ¹ and Q ² are each an aromatic hydrocarbon ring which may have a substituent, or an aromatic heterocycle which may have a substituent, which connects a nitrogen atom to ring A and ring E. It represents a divalent linking group derived from a ring or a direct bond. ) The charge transport material according to claim 1 or 2, wherein both Ar ¹ Ar ² N- and Ar ³ Ar ⁴ N- are N-carbazolyl groups represented by the following structural formula (III).

  The charge transport material according to any one of claims 1 to 3, wherein the ring C is a pyridine ring.   5. The charge transport material according to claim 1, wherein the charge transport material is dissolved in an amount of 2.0% by weight or more with respect to toluene.   A composition for an organic electroluminescence device comprising the charge transport material according to claim 1.   The composition for an organic electroluminescent device according to claim 6, comprising the charge transport material and a phosphorescent material.   Furthermore, a solvent is included, The composition for organic electroluminescent elements of Claim 6 or 7 characterized by the above-mentioned.   6. An organic electroluminescent device having an anode, a cathode, and an organic light emitting layer provided between both electrodes on a substrate, comprising a layer containing the charge transport material according to claim 1. An organic electroluminescent element.

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