JP2008115131A - Organic compound, charge-transporting material, composition for charge-transporting material, and organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge-transporting material excellent in charge-transporting performances and charge-injecting performances as well as in electrochemical stability, a composition for forming an organic electroluminescent element enabling low-voltage driving and exhibiting a high efficiency and a long life, and an organoelectroluminescent element using the same. <P>SOLUTION: The organic compound is represented by formula (I). The charge-transporting material is composed of the organic compound. The organic electroluminescent element has a layer containing the charge-transporting material. In the formula, the ring A and the ring B are each independently an aromatic 6-membered or aliphatic 6-membered ring. The ring A and the ring B may have each independently a substituent group. The ring A and the ring B may form each independently a condensed ring together with another ring. Ar<SP>1</SP>and Ar<SP>2</SP>are each independently an aromatic hydrocarbon group or an aromatic heterocyclic group that is optionally substituted, provided that Ar<SP>1</SP>and Ar<SP>2</SP>are not linked together to form a ring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a novel organic compound, a charge transport material comprising the organic compound, and a composition for a charge transport material containing the charge transport material.
The present invention also relates to a high-efficiency and long-life organic electroluminescence device capable of being driven at a low voltage, using the charge transport material made of the novel organic compound.

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

  Non-Patent Document 1 proposes the following compound (C-1) having a high triplet excitation level as a host material (charge transport material used for a light emitting layer) of a blue phosphorescent light emitting device.

  However, since the compound (C-1) has only a carbazolyl group that cannot be said to have high hole transporting ability and electron transporting ability as a charge transporting group, the compound (C-1) has a charge transporting ability. Is low. Furthermore, since the compound (C-1) has a large energy difference between HOMO and LUMO, holes are not easily injected from the layer on the anode side, and electrons are not easily injected from the layer on the cathode side. For these reasons, the device using the compound (C-1) as the charge transport material has a high driving voltage. Moreover, since the compound (C-1) has very low heat resistance, the driving stability of the device using the compound (C-1) cannot be expected at all.

  Non-Patent Document 2 proposes the following compound (C-2) as a blue fluorescent light-emitting material.

Since the compound (C-2) contains an aromatic tertiary amine and a pyridine ring, the hole transport property and the electron transport property are high, and the charge injection is considered to be good.
However, since all the pyridyl groups are unsubstituted in the compound (C-2), the durability against oxidation and reduction (electrochemical stability) is poor, and the driving stability of the device using the compound (C-2) is low. I have to say that sex is problematic. Further, the compound (C-2) has low heat resistance, and improvement is also required in this respect.

For these reasons, there has been a demand for a material that is excellent in charge transport ability and charge injection ability and excellent in electrochemical stability.
Furthermore, in addition to the above characteristics, a material having a high triplet excitation level has been desired as a host material for a blue phosphorescent light emitting device.
Applied Physics Letters 2003, 82, 15, 242-2424 Journal of Materials Chemistry 2002, 12, 206-212

  The present invention has been made in view of the above circumstances, and has a charge transporting material having excellent charge transporting ability and charge injecting ability as well as excellent electrochemical stability, and high efficiency and long life that can be driven at a low voltage. It is an object of the present invention to provide a composition for forming the organic electroluminescent device and an organic electroluminescent device using the composition.

As a result of intensive studies, the present inventors have found an organic compound having the following structure.
This organic compound has not only excellent charge transporting ability and charge injecting ability, but also excellent electrochemical stability, heat resistance, high triplet excitation level, and resistance to organic solvents. Excellent solubility.
For this reason, according to the organic electroluminescence device using the charge transport material comprising the organic compound and the composition for the charge transport material including the charge transport material comprising the organic compound, low voltage driving is possible and high efficiency is achieved. An organic electroluminescent device having a long lifetime is also provided.

  The present invention has been achieved based on such findings, and the gist of the present invention is an organic compound represented by the following formula (I) (Claim 1), a charge transport material comprising the compound (Claim) 6), a composition for a charge transport material containing the material (claim 8).

  Another gist of the present invention is an organic electroluminescent device having a layer containing the charge transport material in an organic electroluminescent device having an anode, a cathode, and a light emitting layer provided between both electrodes on a substrate. (Claim 10).

〔式中、環Ａおよび環Ｂは各々独立に芳香族六員環または脂肪族六員環を表す。環Ａおよび環Ｂは、各々独立に置換基を有していてもよい。また、環Ａおよび環Ｂは、各々独立に、他の環とともに縮合環を形成していてもよい。Ａｒ^１およびＡｒ^２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芳香族複素環基を表す。但し、Ａｒ^１とＡｒ^２は互いに結合して環を形成することはない。〕

[Wherein, ring A and ring B each independently represent an aromatic 6-membered ring or an aliphatic 6-membered ring. Ring A and ring B may each independently have a substituent. Ring A and ring B may each independently form a condensed ring together with other rings. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. However, Ar ¹ and Ar ² are not bonded to each other to form a ring. ]

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

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

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

  The organic electroluminescent device of the present invention using the charge transport material of the present invention and the composition for a charge transport material containing the 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, liquid crystal displays and instrument backlights), display boards, and sign lamps that take advantage of the characteristics of displays and surface light emitters, and have great technical value. It is.

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

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

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

〔式中、環Ａおよび環Ｂは各々独立に芳香族六員環または脂肪族六員環を表す。環Ａおよび環Ｂは、各々独立に置換基を有していてもよい。また、環Ａおよび環Ｂは、各々独立に、他の環とともに縮合環を形成していてもよい。Ａｒ^１およびＡｒ^２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芳香族複素環基を表す。但し、Ａｒ^１とＡｒ^２は互いに結合して環を形成することはない。〕

[Wherein, ring A and ring B each independently represent an aromatic 6-membered ring or an aliphatic 6-membered ring. Ring A and ring B may each independently have a substituent. Ring A and ring B may each independently form a condensed ring together with other rings. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. However, Ar ¹ and Ar ² are not bonded to each other to form a ring. ]

[1] Structural features Since the organic compound of the present invention contains an aromatic tertiary amine and a pyridine ring, the hole transport property and the electron transport property are high, and the energy difference between HOMO and LUMO is small. Hole injection is easy, and electron injection from the cathode side is also easy. Therefore, the organic electroluminescent element using the organic compound of the present invention can be driven at a low voltage.
Moreover, since the pyridine ring has two substituents, the organic compound of the present invention is excellent in electrochemical stability. Therefore, the organic electroluminescent element using the organic compound of the present invention is excellent in driving stability.

  Furthermore, the organic compound of the present invention has a structure in which a site having an essentially high triplet excitation level, such as an azol ring-pyridine ring-tertiary amine, is connected by a C—N bond. An organic compound has a high triplet excitation level and also has a high singlet excitation level. Therefore, the luminous efficiency of the organic electroluminescent element using the organic compound of the present invention is high. In particular, the high triplet excited level of the organic compound of the present invention is effective when used as a charge transport material for a blue phosphorescent light emitting device.

[2] Molecular weight range The molecular weight of the organic compound of the present invention is usually 10,000 or less, preferably 5000 or less, more preferably 2500 or less, and usually 300 or more, preferably 500 or more, more preferably 600 or more.
If the molecular weight exceeds the upper limit, purification may be difficult due to the high molecular weight of impurities, and if the molecular weight is lower than the lower limit, the glass transition temperature, the melting point, the vaporization temperature, etc. will decrease. There is a risk that the properties are significantly impaired.

[3] Physical Properties The organic compound of the present invention usually has a glass transition temperature of 40 ° C. or higher, but from the viewpoint of heat resistance, the glass transition temperature is preferably 80 ° C. or higher, and more preferably 120 ° C. or higher. preferable.
The organic compound of the present invention usually has a vaporization temperature of 300 ° C. or higher and 800 ° C. or lower.

[4] Ring A, Ring B
Ring A and ring B in the organic compound of the present invention each independently represent an arbitrary six-membered ring optionally having a substituent.
The arbitrary six-membered ring may be an aromatic ring or an aliphatic ring.

  Examples of the aromatic ring include single rings such as a benzene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, and a triazine ring.

As an aliphatic ring, the structure obtained by hydrogenating a part or all of said aromatic ring is mentioned, for example.
In addition, the condensed ring formed by ring A and ring B with each other independently includes naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring And condensed rings containing 6-membered rings such as a fluoranthene ring, a benzofuran ring, a benzothiophene ring, an imidazole ring, an indole ring, a carbazole ring, a quinoline ring, an isoquinoline ring, a sinoline ring and a quinoxaline ring.

  In terms of heat resistance and electrochemical stability of the organic compound, preferred combinations of ring A and ring B are shown below by exemplifying an azole ring group having ring A and ring B.

Among them, both ring A and ring B are preferably benzene rings.
That is, the organic compound of the present invention is preferably represented by the following formula (III).

〔式中、Ａｒ^１、Ａｒ^２は、前記式（Ｉ）におけると同義である。〕

[Wherein, Ar ¹ and Ar ² have the same meanings as in the formula (I). ]

  Examples of optional substituents that ring A and ring B 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, tert -Butyl group and the like).
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl and 1-butenyl groups);
An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms, such as ethynyl and propargyl groups);
An aralkyl group which may have a substituent (preferably an aralkyl group having 7 to 15 carbon atoms, such as a benzyl group);
An optionally substituted amino group [preferably an alkylamino group having one or more optionally substituted alkyl groups having 1 to 8 carbon atoms (for example, methylamino, dimethylamino, diethylamino, Dibenzylamino group, etc.),
An arylamino group having an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent (for example, phenylamino, diphenylamino, ditolylamino group, etc.);
A heteroarylamino group having a 5- or 6-membered aromatic heterocyclic ring which may have a substituent (for example, pyridylamino, thienylamino, dithienylamino group, etc.);
An acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent (for example, acetylamino, benzoylamino group and the like)],
An alkoxy group which may have a substituent (preferably an alkoxy group having 1 to 8 carbon atoms which may have a substituent, for example, methoxy, ethoxy, butoxy group, etc.),
An aryloxy group which may have a substituent (preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy group, etc.) ),
A heteroaryloxy group optionally having a substituent (preferably one having a 5- or 6-membered aromatic heterocyclic group, such as pyridyloxy, thienyloxy group, etc.),
An acyl group which may have a substituent (preferably an acyl group having 2 to 10 carbon atoms which may have a substituent, such as formyl, acetyl and benzoyl groups);
An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, for example, methoxycarbonyl, ethoxycarbonyl group and the like),
An aryloxycarbonyl group which may have a substituent (preferably an aryloxycarbonyl group having 7 to 13 carbon atoms which may have a substituent, such as a phenoxycarbonyl group. ),
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms which may have a substituent, such as an acetoxy group);
Halogen atoms (especially fluorine or chlorine atoms),
Carboxyl group,
A cyano group,
Hydroxyl group,
Mercapto group,
An alkylthio group which may have a substituent (preferably an alkylthio group having 1 to 8 carbon atoms, such as a methylthio group and an ethylthio group);
An arylthio group which may have a substituent (preferably an arylthio group having 6 to 12 carbon atoms, such as a phenylthio group and a 1-naphthylthio group).
An alkylsulfonyl group or an arylsulfonyl group which may have a substituent (for example, a mesyl group, a tosyl group, etc.),
A silyl group which may have a substituent (for example, a trimethylsilyl group, a triphenylsilyl group, etc.),
An optionally substituted boryl group (for example, a dimesitylboryl group),
A phosphino group which may have a substituent (for example, a diphenylphosphino group);
An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc. And a monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-5 condensed ring).
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, oxadiazol ring, Indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, chloropyrrole ring, furofuran ring, thienofuran ring, benzoisoxazol Ring, benzisothiazol ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring And monovalent groups derived from a 5- or 6-membered monocyclic ring or a 2-4 condensed ring, such as a quinazoline ring.)

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

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

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

  Moreover, it is preferable that the ring A and the ring B do not have a substituent from the viewpoint of preventing the triplet excited level from being lowered.

[5] Ar ¹ , Ar ²
Ar ¹ and Ar ² in the organic compound of the present invention each independently represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. However, Ar ¹ and Ar ² are not bonded to each other to form a ring.

Examples of the substituent that Ar ¹ and Ar ² may have include the substituents exemplified as the substituent that ring A and ring B may have, and a plurality of these substituents may be linked. It may be. Ar ¹ and Ar ² each independently include a substituent, and usually have a molecular weight of 5,000 or less, preferably 2,500 or less.

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

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

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

Examples of aromatic heterocyclic groups applicable to Ar ¹ and Ar ² are furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazo- Ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, chloropyrrole ring, furofuran ring, thienofuran ring, benzo Isoxazole ring, benzisothiazol ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, 5- or 6-membered benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. It includes monocyclic or 2-4 fused ring group derived from the.

Ar ¹ and Ar ² are groups derived from a benzene ring which may have a substituent, a group in which a plurality of (for example, 2 to 10) benzene rings are linked (for example, from the viewpoint of preventing a decrease in triplet excited level) , A biphenylene group, a terphenylene group, etc.) and a group derived from a pyridine ring are preferable.

Further, Ar ¹ and Ar ² are preferably groups in which one or both are derived from a pyridine ring from the viewpoint of further improving the electron transport ability.

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

〔式中、環Ａ、環Ｂ、Ａｒ^１、Ａｒ^２は、前記式（Ｉ）におけると同義である。〕

[Wherein, ring A, ring B, Ar ¹ and Ar ² have the same meanings as in formula (I). ]

In addition, from the viewpoint of further improving the heat resistance while maintaining a high triplet excitation level, the organic compound of the present invention preferably has two or more N-carbazolyl groups represented by the following formula (IV). It is preferable that Ar ¹ has one or more, preferably 1 to 6, N-carbazolyl groups represented by the following formula (IV).

In addition, Ar ¹ is particularly preferably a 6- (N-carbazolyl) -2-pyridyl group or a 3- (N-carbazolyl) phenyl group from the viewpoint of further improving the electron transport ability and heat resistance.
That is, the organic compound of the present invention is particularly preferably represented by the following formula (IV-1).

〔式中、Ａｒ^２は、前記式（Ｉ）におけると同義であり、ＹはＣＨ又はＮを表す。〕

[In the formula, Ar ² has the same meaning as in formula (I), and Y represents CH or N. ]

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

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

First, a dihalogenated pyridine represented by the formula (i-1) and an azole compound represented by the formula (i-2) are mixed with copper powder, copper (I) halide, copper (I) oxide, palladium. Transition metal catalysts such as complexes (about 0.0001 to 5 equivalents relative to dihalogenated pyridine) and basic substances such as potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert-butoxy sodium, triethylamine (dihalogen) In the presence of about 0.1 to 10 equivalents relative to pyridine), in an inert gas stream, in the absence of a solvent, or in a solvent such as an aromatic solvent or an ether solvent, at a temperature of 20 to 300 ° C., 1 to 60 The compound represented by formula (i-3) is obtained by stirring and mixing for a period of time. Next, the compound represented by the formula (i-3) and the secondary amine compound represented by the formula (i-4) are mixed with copper powder, copper (I) halide, copper (I) oxide, palladium complex. Transition metal catalysts (about 0.001 to 5 equivalents relative to the halogen atom of the compound represented by formula (i-3)), potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert-butoxy In the presence of a basic substance such as sodium or triethylamine (about 1 to 10 equivalents relative to the halogen atom of the compound represented by the formula (i-3)) under an inert gas stream, no solvent or an aromatic solvent, The organic compound of the present invention represented by the formula (I) can be obtained by stirring and mixing in a solvent such as an ether solvent at 20 to 300 ° C. for 1 to 60 hours. In the above reaction formula, ring A, ring B, Ar ¹ and Ar ² have the same meaning as in formula (I). X represents a halogen atom.

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

  Specifically, extraction (including suspension washing, boiling washing, ultrasonic washing, acid-base washing), adsorption, occlusion, melting, crystallization (including recrystallization from solvent, reprecipitation), distillation (atmospheric pressure) Distillation, vacuum distillation), evaporation, sublimation (atmospheric pressure sublimation, vacuum sublimation), ion exchange, dialysis, filtration, ultrafiltration, reverse osmosis, pressure osmosis, zone lysis, electrophoresis, centrifugation, flotation separation, sedimentation separation, Magnetic separation, various types of 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.

  Product confirmation and purity analysis methods include gas chromatograph (GC), high performance liquid chromatograph (HPLC), high performance amino acid analyzer (AAA), capillary electrophoresis measurement (CE), size exclusion chromatograph (SEC). , Gel permeation chromatography (GPC), cross-fractionation chromatography (CFC) mass spectrometry (MS, LC / MS, GC / MS, MS / MS), nuclear magnetic resonance apparatus (NMR (1HNMR, 13CNMR)), Fourier Conversion Infrared Spectrometer (FT-IR), Ultraviolet Visible Near Infrared Spectrometer (UV.VIS, NIR), Electron Spin Resonator (ESR), Transmission Electron Microscope (TEM-EDX) Electron Beam Microanalyzer (EPMA) ), Metal element analysis (ion chromatograph, inductively coupled plasma-emission spectroscopy (ICP-AES) atomic absorption analysis ( AS) X-ray fluorescence analyzer (XRF)), nonmetal element analysis, trace analysis (ICP-MS, GF-AAS, optionally a GD-MS), etc., it is applicable.

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

[Charge transport material]
The charge transport material of the present invention is composed of the organic compound of the present invention, and preferably dissolves in an amount of 1.0% by weight or more, more preferably 3.0% by weight or more in toluene.

As will be described later, the hydrocarbon contained in the charge transport material composition is preferably an aromatic hydrocarbon. Toluene is listed as a representative example of aromatic hydrocarbons, and in the present invention, toluene is used as an index indicating the solubility of an organic compound (charge transport material).
It is preferable that the charge transport material of the present invention has a solubility in toluene of 1.0% by weight or more because a layer constituting the organic electroluminescence device can be easily formed by a wet film forming method. The upper limit of the solubility is not particularly limited, but is usually about 50% by weight.

[Composition for charge transport material]
The composition for a charge transport material of the present invention contains at least the charge transport material described above. Usually, it further contains a solvent, and preferably further contains a light emitting material.
The composition for a charge transport material of the present invention is preferably used for an organic electroluminescence device.

(1) Solvent Various solvents can be applied as the solvent contained in the composition for a charge transport material of the present invention, and the solvent is not particularly limited. 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 aniso Aromatic ethers such as benzene, phenitol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole; phenyl acetate, Aromatic esters such as phenyl propionate, methyl benzoate, 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, cyclohexano Alcohol having an alicyclic ring, cyclooctanol, etc .; aliphatic alcohol such as butanol, hexanol; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1 -Aliphatic ethers such as monomethyl ether acetate (PGMEA); aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate.

  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 use of a nitrogen gas seal and a desiccant, dehydration of the solvent in advance, and use of a solvent with low water solubility. 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 charge transport material composition of the present invention contains, for example, 10% by weight of a solvent having a water solubility at 25 ° C. of 1% by weight or less, preferably 0.1% by weight or less. % Or more is preferable.

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

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

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

In the composition for a charge transport material of the present invention, the light emitting material is preferably a low molecular weight material, and is preferably used for an organic electroluminescence device in which a layer containing the light emitting material is formed by a wet film forming method. The composition for a charge transport material of the present invention contains a light emitting material and is usually used for forming a light emitting layer, but may be used for other layers such as a hole transport layer.
As used herein, the low molecular weight material is a substance other than a substance composed of a high molecular weight polymer or a condensate molecule produced by repeating a chain reaction of the same reaction or a similar reaction with a low molecular weight compound. Refers to a compound that is substantially single.

  As the luminescent material, any known material can be applied, and a fluorescent luminescent material or a phosphorescent luminescent material can be used alone or in combination. A phosphorescent luminescent material is preferable from the viewpoint of internal quantum efficiency.

  For the purpose of improving the solubility in a solvent, the symmetry and rigidity of the light emitting material molecule may be reduced, or a lipophilic substituent such as an alkyl group may be introduced.

  Examples of the fluorescent material that gives blue light emission include perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof. Examples of the fluorescent material that gives green light emission include quinacridone derivatives and coumarin derivatives. Examples of the fluorescent material that gives yellow light include rubrene and perimidone derivatives. Examples of the fluorescent light-emitting material that emits red light 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およびＲ^９５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 R ⁹⁵ is not.)

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 An acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group; an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, and a phenanthyl group.

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

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

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

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

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

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

  In addition, the group of ring A2 and ring A2 ′ is preferably a pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazol group, benzoxazole group, benzoimidazole group, quinolyl group, isoquinolyl group, for example. Quinoxalyl group, phenanthridyl group and the like.

  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 An alkenyl group such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group such as a methoxy group and an ethoxy group; an aryloxy group such as a phenoxy group and a benzyloxy group; a dimethylamino group and a diethylamino group A dialkylamino 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. 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 these, 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 are more preferable. Groups.

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, That is, a compound having 2-arylpyridine, a compound in which an arbitrary substituent is bonded thereto, and a compound in which an arbitrary group is condensed to this is preferable.

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

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

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

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

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

  In addition, compounds described in WO2005 / 019373 can also be used.

[3] Other components The composition for a charge transport material used as the composition for a charge transport material of the present invention contains various other solvents as necessary in addition to the solvent and the light emitting material described above. You may go out. 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 charge transport material composition The solids concentration of the charge transport material, light emitting material, and components that can be added as required (leveling agent, etc.) in the charge transport material composition is Is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, further preferably 0.5% by weight or more, most preferably 1% by weight or more, and usually 80% by weight or more. % By weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, further preferably 30% by weight or less, and most preferably 20% by weight or less. If this concentration is below the lower limit, it is difficult to form a thick film when forming a thin film, and if it exceeds the upper limit, it may be difficult to form a thin film.

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

[5] Method for Preparing Charge Transport Material Composition The charge transport material composition of the present invention comprises a charge transport material, a light emitting material, and various additives such as a leveling agent and an antifoaming agent that can be added as necessary. The resulting solute is prepared by dissolving 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 charge transport materials
When an organic electroluminescent element is produced by forming a layer by a wet film-forming method using the composition for charge transport material of the present invention, if water is present in the composition for charge transport material to be used, moisture is formed in the formed film. As a result, it is preferable that the water content in the composition for a charge transport material of the present invention is as small as possible. In general, since organic electroluminescent devices use many materials such as cathodes that deteriorate significantly due to moisture, when moisture is present in the composition for charge transport material, moisture remains in the dried film. The possibility of deteriorating the characteristics of the element is considered, which is not preferable.

  Specifically, the amount of water contained in the composition for a charge transport material of the present invention 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 charge transport materials, 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 a charge transport material of the present invention is preferably in a uniform liquid state at room temperature in order to improve stability in a wet film forming process, for example, ejection stability from a nozzle in an ink jet film forming method. 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 charge transport material of the present invention, when the viscosity is extremely low, 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. When the viscosity is extremely high, 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 charge transport material 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 easily disturbed during drying. 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 charge transport material of the present invention is high, problems such as changes in solute concentration due to evaporation of the solvent are likely 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 Charge Transport Material The composition for a charge transport material of the present invention is preferably filled in a container capable of preventing the transmission of ultraviolet rays, such as a brown glass bottle, and stored tightly. . The storage temperature is usually −30 ° C. or higher, preferably 0 ° C. or higher, and usually 35 ° C. or lower, preferably 25 ° C. or lower.

[Organic electroluminescence device]
The organic electroluminescence device of the present invention has at least an anode, a cathode and a light emitting layer provided between both electrodes on a substrate, and has a layer containing the charge transport material of the present invention. To do. This layer is a layer formed by a wet film forming method, and this layer is particularly preferably an organic light emitting layer.

  1 to 8 are schematic cross-sectional views showing structural examples suitable for the organic electroluminescence device of the present invention. In FIGS. 1 to 8, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, and 4 is light emission. Layer 5 is an electron injection layer, 6 is a cathode, 7 is an electron transport layer, 8 is a hole blocking layer, and 9 is an electron blocking layer. 10 represents each hole transport layer.

[1] Substrate The substrate 1 serves as a support for the organic electroluminescent element, and quartz, glass plates, metal plates, metal foils, plastic films, sheets, and the like are used. In particular, a glass plate and a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone and the like are 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 securing 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 one of preferable methods.

[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 made of metal such as aluminum, gold, silver, nickel, palladium, platinum, metal oxide such as oxide of indium and / or tin, metal halide such as copper iodide, carbon black, Alternatively, it is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by sputtering, vacuum deposition, or the like. In addition, when forming an anode using fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder is used. The anode 2 can also be formed by dispersing it in a resin solution and applying it onto 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.

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

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

(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^１０１およびＲ^１０２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 ¹⁰¹ and R ¹⁰² 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.

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.

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

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

  The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. 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 further more preferable.

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

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

  Specific examples of an onium salt substituted with an organic group, a cyano compound, and an aromatic boron compound suitable as an electron-accepting compound include those described in WO 2005/089024, and suitable examples thereof are also the same. Although the compound (A-1) represented by the following structural formula is mentioned, it is not limited to them at all.

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

  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, spin coat, spray coat, dip coat, die coat, flexographic printing, screen printing The positive hole injection layer 3 is formed by coating on the anode by a wet film forming method such as an ink jet method and drying.

  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.

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] Hole Transport Layer In FIGS. 7 and 8, the hole transport layer 10 is provided on the hole injection layer 3. The conditions required for the material of the hole transport layer 10 are required to be a material that has a high hole injection efficiency from the anode 2 and can efficiently transport the injected holes. For this purpose, the ionization potential is low, the transparency to visible light is high, the hole mobility is high, the stability is high, and impurities that become traps are unlikely to be generated during manufacturing or use. Required. Further, in order to contact the light emitting layer 4, it is required not to quench the light emitted from the light emitting layer 4 or form an exciplex with the light emitting layer 4 to reduce the efficiency. In addition to the above general requirements, when the application for in-vehicle display is considered, the element is further required to have heat resistance. Accordingly, a material having a glass transition temperature of 80 ° C. or higher, more preferably 85 ° C. or higher is preferable.

  Such a hole transporting material is 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl, similar to the hole transporting material used for the host material of the light emitting layer 4. Aromatic diamines containing two or more representative tertiary amines and having two or more condensed aromatic rings substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234811), 4,4 ′, 4 ″ -tris (1 An aromatic amine compound having a starburst structure such as (naphthylphenylamino) triphenylamine (J. Lumin., 72-74, 985, 1997), a fragrance comprising a tetramer of triphenylamine Spiro compounds such as group amine compounds (Chem. Commun., 2175, 1996), 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene ( ynth.Metals, 91, 209, 1997), carbazole derivatives such as 4,4′-N, N′-dicarbazol-biphenyl, etc. These compounds are used alone. Alternatively, a plurality of types may be mixed and used as necessary.

  In addition to the above compounds, as a material for the hole transport layer, polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), polyarylene ether-tersulfone (Polym. Adv. Tech., Vol. 7, p. 33, 1996).

  The hole transport layer is formed by a wet method such as a normal coating method such as a spray method, a printing method, a spin coating method, a dip coating method, a die coating method, or various printing methods such as an ink jet method or a screen printing method. It can be formed by a dry film formation method such as a film formation method or a vacuum evaporation method.

  In the case of a wet film-forming method, an additive such as a binder resin or a coating property improving agent that does not become a hole trap is added to one or more of the hole transport materials, if necessary, and dissolved in an appropriate solvent. Then, a coating solution is prepared, applied onto the anode 2 or the hole injection layer 3 by a method such as a spin coating method, and dried to form the hole transport layer 10. Examples of the binder resin include polycarbonate, polyarylate, and polyester. If the binder resin is added in a large amount, the hole mobility is lowered. Therefore, it is preferable that the binder resin is small, and the content in the hole transport layer 10 is usually preferably 50% by weight or less.

  In addition, you may use the composition for charge transport materials of this invention in order to form the positive hole transport layer 10. FIG.

The thickness of the hole transport layer 10 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less. In order to uniformly form such a thin film, a vacuum deposition method is generally used.
The hole transport layer 10 may be omitted as shown in FIGS.

[5] Light emitting layer (organic light emitting layer)
On the hole injection layer 3 or the hole transport layer 10, the light emitting layer 4 is usually provided. In the present invention, the light-emitting layer 4 is preferably a layer formed by a wet film-forming method using a composition containing a low-molecular light-emitting material. Between the electrodes to which an electric field is applied, holes are formed from the anode 2 to the hole. This is a layer that is excited by recombination of holes injected through the injection layer 3 and electrons injected from the cathode 6 through the electron injection layer 5 to become a main light emitting source. The light-emitting layer 4 preferably contains a light-emitting material (dopant) and one or more host materials, and a charge transport material composition containing the charge transport material of the present invention and a low-molecular light-emitting material. And preferably formed by a wet film formation method.

  Here, the wet film forming method means that the composition for a charge transport material of the present invention containing the above-mentioned solvent is spin coated, spray coated, dip coated, die coated, flexographic printing, and screen printing. The film is formed by coating by an ink jet method.

  In addition, the light emitting layer 4 may contain another material and a component in the range which does not impair the performance of the organic electroluminescent element of this invention.

  In general, in the organic electroluminescence device, when the same material is used, the thinner the film thickness between the electrodes is, the larger the effective electric field is. 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.

[6] Hole blocking layer When a phosphorescent dye is used as the light emitting material or a fluorescent light emitting material that emits blue light is used, hole blocking is performed on the light emitting layer 4 as shown in FIGS. It is effective to provide the layer 8. 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 7 in the direction of the light emitting layer 4.

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

  The physical properties required for the material constituting the hole blocking layer 8 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). ) Is high. Examples of the material of the hole blocking layer 8 that satisfies such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed ligand complexes, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, styryls such as distyrylbiphenyl derivatives Compounds (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 (JP-A-10-79297). Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in WO2005 / 022962 is also preferable as the hole blocking material.

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

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

[7] Electron Transport Layer In FIGS. 2 to 4, 7 and 8, the electron transport layer 7 is provided between the light emitting layer 4 and the electron injection layer 5 or the cathode 6 for the purpose of further improving the light emission efficiency of the device. Provided. The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 6 between electrodes to which an electric field is applied in the direction of the light emitting layer 4.

As an electron transport compound used for the electron transport layer 7, the electron injection efficiency from the cathode 6 or the electron injection layer 5 is high, and the injected electrons can be efficiently transported with high electron mobility. It must be a compound. Materials satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazol derivatives
, Distyrylbiphenyl derivatives, silole derivatives, 3- or 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazol metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline Compound (JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous Examples thereof include silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

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

The electron transport layer 7 is formed by laminating on the light emitting layer 4 or the hole blocking layer 8 by the wet film forming method or the vacuum deposition method in the same manner as the hole injection layer 3. Usually, a vacuum deposition method is used.
The electron transport layer 7 may be omitted as shown in FIGS.

[8] Electron Injection Layer The electron injection layer 5 serves to efficiently inject 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.

Moreover, it is also possible to insert an ultrathin insulating film (0.1 to 5 nm) such as LiF, MgF ₂ , Li ₂ O, CsCO _{3 at} the interface between the cathode 6 and the light emitting layer 4 or the electron transport layer 7. (Appl. Phys. Lett., 70, 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, 44, 1245, 1997; SID 04) Digest, page 154).

  Furthermore, an alkali metal such as sodium, potassium, cesium, lithium, rubidium or the like is added to an organic electron transport material typified by a nitrogen-containing heterocyclic compound such as bathophenanthroline described later or a metal complex such as an aluminum complex of 8-hydroxyquinoline. (In Japanese Patent Application Laid-Open No. 10-270171, Japanese Patent Application Laid-Open No. 2002-1000047, Japanese Patent Application Laid-Open No. 2002-1000048, and the like), electron injection / transport properties are improved and excellent film quality can be achieved. This is preferable because it becomes possible. 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 or the electron transport layer 7 by the wet film forming method or the 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 into a crucible or a 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 The boat is heated and evaporated to form the electron injection layer 5 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, and the electron injection layer 5 is formed on the substrate placed facing the crucible and dispenser.

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

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

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

[10] Other constituent layers Between the anode 2 and the cathode 6 and the light emitting layer 4 in the organic electroluminescent element of the present invention, any layer other than the layers described above may be used as long as the performance is not impaired. In addition, any layer other than the light emitting layer 4 may be omitted.

  For example, as described above, 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) Hole blocking layer / There are uses such as stacking of electron transport layers, 4) not using, and the like.

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

  The characteristics required for the electron blocking layer 9 include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Further, when the light emitting layer 4 is formed by a wet film forming method, it is preferable that the electron blocking layer 5 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 formation compatibility, and examples of the material used for such an electron blocking layer 9 include F8-TFB in addition to the organic electroluminescent element composition described above. And a copolymer of dioctylfluorene and triphenylamine (described in WO 2004/084260).

The structure opposite to that shown in FIG. 1, that is, the cathode 6, the electron injection layer 5, the light emitting layer 4, the hole injection layer 3, and the anode 2 can be laminated on the substrate 1 in this order. It is also possible to provide an organic electroluminescent element between two substrates, at least one of which is highly transparent. Furthermore, a structure in which a plurality of layers shown in FIG. 1 are stacked (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, instead of the interfacial layer (between the light emitting units) (when the anode is ITO and the cathode is Al, the two layers), for example, V ₂ O ₅ is used as the charge generation layer (CGL). This is more preferable from the viewpoint of luminous efficiency and driving voltage. The same applies to FIGS.

  The organic electroluminescence device to which the present embodiment is applied applies to any of a single device, a device having a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix. be able to.

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

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

(Example 1: objects 1 to 3)

  In a nitrogen stream, carbazole (18.8 g), 2,6-dibromopyridine (80.0 g), copper powder (14.4 g), potassium carbonate (31.2 g), and tetraglyme (80 ml) The mixture was stirred for 7 hours while being heated to ° C. and allowed to cool to room temperature. Chloroform was added to the reaction mixture, and insoluble matters were filtered off. Chloroform contained in the filtrate was distilled off under reduced pressure, an ethanol / water (40/1) mixture was added, and the precipitate was separated by filtration. Water was added to the filtrate, and the precipitate was collected by filtration, washed with ethanol, and purified by silica gel column chromatography (n-hexane / methylene chloride = 2/1) to give the desired product 1 (17 0.7 g) was obtained.

  Heat the target 1 (9.00 g), copper (I) iodide (12.9 g), potassium iodide (29.6 g), and N, N-dimethylformamide (30 ml) to 160 ° C. in a nitrogen stream. The mixture was stirred for 7 hours and allowed to cool to room temperature. The reaction mixture was added to 0.1N hydrochloric acid and stirred, and then the precipitate was filtered off and washed with ethanol. Chloroform was added to the obtained solid content, and the mixture was stirred for 30 minutes with heating under reflux to dissolve soluble components, and then the solution components were separated by filtration and concentrated. The resulting solid was purified by recrystallization from methanol to obtain the desired product 2 (8.82 g) as white crystals.

  In a nitrogen stream, bis (4-aminophenyl) ether (0.94 g), target 2 (10.5 g), copper powder (1.19 g), potassium carbonate (3.92 g), and tetraglyme (12 ml) ) Was added to a 50 mL four-necked flask, placed in an oil bath at 200 ° C. and stirred for 15 hours. After dilution with dichloromethane and filtration, methanol was added to the oil obtained by evaporation under reduced pressure to obtain a light brown powder. This was purified by column chromatography, heated and washed with ethyl acetate, and then again washed with methanol to obtain the target product 3 (1.9 g) as a white powder.

DEI-MS m / z = 1168 (M ⁺ )
This had a glass transition temperature of 151 ° C., a melting point of 231 ° C., a vaporization temperature of 568 ° C., and was 1.4% by weight soluble in toluene.

(Example 2: objects 4 and 5)

  Into the atmosphere, a mixed solution of 3- (N-carbazolyl) nitrobenzene (25 g) and ethanol (400 ml) was stirred, and after adding concentrated aqueous hydrochloric acid (150 ml), the mixture was heated and heated under reflux. Reduced iron powder (24.2 g) was added in small portions and stirred for an additional 45 minutes. With the resulting solution cooled in an ice bath, aqueous ammonium hydroxide (28%, 500 ml) was added. Methylene chloride (600 ml) was added thereto and stirred well, and the organic layer was dried over anhydrous sodium sulfate and concentrated. The obtained residue was purified by silica gel column chromatography (methylene chloride solvent) to obtain the target product 4 as pale pink crystals (17.7 g).

In a nitrogen stream, target product 4 (5.62 g), target product 2 (6.40 g), dehydrated toluene (50 ml), and sodium t-butoxy (2.61 g) were added to a 200 mL four-necked flask. To another container, tris (dibenzylideneacetone) dipalladium (0) chloroform complex (40 mg), 1,1′-bis (diphenylphosphino) ferrocene (88 mg), and dehydrated toluene (10 ml) were added, and 10 minutes at 60 ° C. And a complex solution was prepared. This complex solution was added to the system and stirred at 100 ° C. for 5 hours. After diluting with toluene and removing insolubles by filtration, the filtrate was concentrated under reduced pressure and washed with methanol to obtain a white powder (3.2 g). A part thereof was purified by column chromatography to obtain the target product 5 as a white powder (400 mg).

DEI-MS m / z = 742 (M ⁺ )
This had a glass transition temperature of 123 ° C., a melting point of 223 ° C., a vaporization temperature of 463 ° C., and was 2.0% by weight soluble in toluene.

[Production Example of Organic Electroluminescent Device of the Present Invention]
Examples in which an organic electroluminescent element is produced using the organic compound of the present invention are given below.

(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 to a thickness of 150 nm on a glass substrate 1 (sputtered film-formed product; sheet resistance 15 Ω) is 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. The anode 2 was formed by patterning the stripe. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, then dried with nitrogen blow, and finally UV 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 non-conjugated polymer compound (PB-1 (weight average molecular weight: 26500, number average molecular weight: 12000)) having an aromatic amino group having the structural formula shown below and the structure shown below Using the electron-accepting compound (A-1) of the formula, spin coating was performed under the following conditions.

Spin coating conditions Solvent Anisole Coating solution concentration PB-1 2.0% by weight
A-1 0.4% by weight
Spinner speed 2000rpm
Spinner rotation time 30 seconds Drying conditions 230 ° C. × 5 hours A uniform thin film having a thickness of 30 nm was formed by the above spin coating.

Subsequently, a light emitting layer 4 was deposited on the hole injection layer 3. The following compound (E-1), which is the target product 5 synthesized in Example 2, was used as a material for the light-emitting layer 4 together with an iridium complex (D-1) having the structural formula shown below, and (E-1) The crucible temperature is 276 to 285 ° C. and the deposition rate is 0.08 to 0.1 nm / second, and the iridium complex (D-1) is crucible temperature 256 ° C. and the deposition rate is 0.005 to 0.006 nm / second. It was laminated to a thickness of 9 nm. The degree of vacuum during vapor deposition was 1.4 × 10 ⁻⁴ Pa.

Next, the compound (HB-1) shown below as the hole blocking layer 8 was laminated at a crucible temperature of 349 to 350 ° C. with a deposition rate of 0.08 to 0.1 nm / second and a film thickness of 5 nm. The degree of vacuum during vapor deposition was 1.3 to 1.4 × 10 ⁻⁴ Pa.

Next, a phenanthroline derivative (ET-1) shown below was deposited as an electron transport layer 7 on the hole blocking layer 8 in the same manner. The degree of vacuum during deposition was 1.0 to 1.1 × 10 ⁻⁴ Pa, the deposition rate was 0.08 to 0.1 nm / second, and the film thickness was 30 nm.

  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 vapor-deposited up to the electron transport layer 7 is once taken out from the vacuum vapor deposition apparatus into the atmosphere, and a 2 mm-wide stripe-shaped shadow mask is used as the cathode vapor deposition mask. Was placed in a separate vacuum deposition apparatus so as to be orthogonal to each other, and evacuated until the degree of vacuum in the apparatus was 4.7 × 10 ⁻⁴ Pa or less in the same manner as the organic layer. As the electron injection layer 5, first, lithium fluoride (LiF) was deposited using a molybdenum boat at a deposition rate of 0.01 to 0.015 nm / second, a degree of vacuum of 5.3 × 10 ⁻⁴ Pa, and 0.005. 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 to form an aluminum layer having a thickness of 80 nm at a deposition rate of 0.12 to 0.4 nm / second and a degree of vacuum of 9.3 to 17.3 × 10 ⁻⁴ Pa. Thus, a cathode 6 was formed. The substrate temperature during the 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: 21.5 [cd / A] @ 100 cd / m ²
Voltage: 6.3 [V] @ 100 cd / m ²
Luminous efficiency: 10.8 [1 m / w] @ 100 cd / m ²
The maximum wavelength of the emission spectrum of the device was 470 nm, which was identified as that from the iridium complex (D-1). The chromaticity was CIE (x, y) = (0.157, 0.309).

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

Explanation of symbols

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

Claims (11)

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

[Wherein, ring A and ring B each independently represent an aromatic 6-membered ring or an aliphatic 6-membered ring. Ring A and ring B may each independently have a substituent. Ring A and ring B may each independently form a condensed ring together with other rings. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. However, Ar ¹ and Ar ² are not bonded to each other to form a ring. ] The organic compound of Claim 1 represented by following formula (II).

[Wherein, ring A, ring B, Ar ¹ and Ar ² have the same meanings as in formula (I). ] The organic compound of Claim 1 or 2 represented by following formula (III).

[Wherein, Ar ¹ and Ar ² have the same meanings as in the formula (I). ] The organic compound according to any one of claims 1 to 3, which has two or more N-carbazolyl groups represented by the following formula (IV) as a partial structure.

The organic compound according to any one of claims 1 to 4, wherein Ar ¹ is a group derived from a pyridine ring which may have a substituent.   A charge transport material comprising the organic compound according to any one of claims 1 to 5.   The charge transport material according to claim 6, which dissolves 1.0% by weight or more in toluene.   The composition for charge transport materials containing the charge transport material of Claim 6 or 7.   Furthermore, the composition for charge transport materials of Claim 8 containing a phosphorescence-emitting material.   8. An organic electroluminescence device having an anode, a cathode, and a light emitting layer provided between both electrodes on a substrate, the organic electroluminescence device having a layer containing the charge transport material according to claim 6 or 7.   The organic electroluminescence device according to claim 10, wherein the layer containing the charge transport material is a layer formed using the composition for charge transport material according to claim 8 or 9.

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