JP2007169268A - Organic compound, charge transport material, charge transport material composition, and organic electroluminescent device - Google Patents

Abstract

（式中、各々の芳香族環は置換基を有していてもよい。Ｚは直接結合または置換基を有していてもよいアリーレン基を表し、Ａｒは置換基を有していてもよいアリール基を表す。２つのＡｒは同一であっても異なっていてもよい。なお、Ｚはピリジン環の２位または６位に結合しているフェニル基に連結する。）
【選択図】 なしPROBLEM TO BE SOLVED: To provide an organic compound having both excellent hole transportability and electron transportability, excellent electrochemical durability and high triplet excited level. It is another object of the present invention to provide an organic electroluminescence device having high luminous efficiency and high driving stability and having a long lifetime.
An organic compound represented by the following formula (I):

(In the formula, each aromatic ring may have a substituent. Z represents a direct bond or an arylene group which may have a substituent, and Ar may have a substituent. Represents an aryl group, and two Ars may be the same or different, and Z is linked to a phenyl group bonded to the 2- or 6-position of the pyridine ring.
[Selection figure] None

Description

  The present invention relates to a novel organic compound, a charge transport material comprising the organic compound, a composition containing the organic compound, and an organic electroluminescent device having a layer containing the organic compound.

  An electroluminescent device using an organic thin film has been developed. An electroluminescent element using an organic thin film, that is, an organic electroluminescent element, usually has an organic layer including an anode, a cathode, and at least a light emitting layer provided between both electrodes on a substrate. As the organic layer, in addition to the light emitting layer, a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, and the like are used. Usually, these layers are laminated to be used as an organic electroluminescent element. Conventionally, organic electroluminescent devices have used fluorescent light emission, but in an attempt to increase the light emission efficiency of the device, it has been studied to use phosphorescent light emission instead of fluorescent light. However, even if phosphorescence is used, sufficient luminous efficiency has not been obtained yet. For the light emitting layer, a host material and a dopant material are used. For example, Patent Document 1 proposes the following compounds as the host material of the organic electroluminescent element.

However, the above compound has a poor hole transport property, and as a material for the light emitting layer of the organic electroluminescence device, there is a problem that the balance between the hole transport property and the electron transport property is poor.
International Publication No. WO03 / 080760 Pamphlet

  An object of the present invention is to provide an organic compound having both excellent hole transportability and electron transportability, excellent electrochemical durability, and a high triplet excited level. It is another object of the present invention to provide an organic electroluminescence device having high luminous efficiency and high driving stability and having a long lifetime.

As a result of intensive studies by the present inventors, an organic compound having the following specific structure has excellent hole transportability and electron transportability, and has excellent electrochemical durability and high triplet excitation level. As a result, the present invention has been reached.
That is, the present invention contains an organic compound represented by the following formula (I), a charge transport material comprising the organic compound, a charge transport material composition containing the organic compound, and the organic compound. It exists in the organic electroluminescent element which has a layer.

(In the formula, each aromatic ring may have a substituent. Z represents a direct bond or an arylene group which may have a substituent, and Ar may have a substituent. Represents an aryl group, and two Ars may be the same or different, and Z is linked to a phenyl group bonded to the 2- or 6-position of the pyridine ring.

The organic compound of the present invention has both excellent hole transportability and electron transportability, and has excellent electrochemical durability and high triplet excitation level.
For this reason, according to the organic electroluminescent element which has the layer containing this organic compound, an organic electroluminescent element with high brightness, high efficiency, and long life is provided.
The organic electroluminescence device of the present invention is a flat panel display (for example, for OA computers or wall-mounted televisions), an in-vehicle display device, a light source utilizing characteristics of a mobile phone display or a surface light emitter (for example, a light source of a copying machine, a liquid crystal). It can be applied to backlight sources for displays and instruments, display panels, and indicator lights, and its technical value is great.

  In addition, the charge transport material comprising the organic compound of the present invention and the charge transport material composition containing the organic compound of the present invention have essentially excellent electrochemical durability, and thus are not limited to organic electroluminescent devices, In addition, it is also useful for electrophotographic photoreceptors.

The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the contents are not specified.
<Organic compounds>
The organic compound of the present invention is represented by the following formula (I).

(In the formula, each aromatic ring may have a substituent. Z represents a direct bond or an arylene group which may have a substituent, and Ar may have a substituent. Represents an aryl group, and two Ars may be the same or different, and Z is linked to a phenyl group bonded to the 2- or 6-position of the pyridine ring.
The organic compound of the present invention has an electron transport performance by bonding a carbazole ring substituted with an aryl group at the 3-position and 6-position to a pyridine ring substituted at the 2-position, 4-position and 6-position with a phenyl group. A pyridine ring skeleton having a carbazole ring skeleton having a hole transport performance and further substituted with an aryl group at the 3rd and 6th positions of the carbazole ring improves the hole transport performance over an unsubstituted carbazole ring. The organic electroluminescent device, particularly the phosphorescent organic electroluminescent device has high luminous efficiency and high because the balance between the two performances is good and the oxidation reversibility is good and the structure is very stable to oxidation. It is presumed that an organic electroluminescent element having driving stability can be obtained.
In addition, by introducing aryl groups at the 3-position and 6-position of the carbazole ring, a compound having a drastic improvement in the glass transition temperature of the compound can be obtained. In addition, a group that substitutes a carbon atom in the para position with respect to the nitrogen atom in the pyridine ring, By doing so, the solubility in a solvent is improved, and the formation of a light emitting layer by a wet film forming method is facilitated.

Each aromatic ring in formula (I) may have a substituent, and examples of the substituent include groups described in the following substituent group X. The substituent of the aromatic ring may be bonded to an adjacent group or the aromatic ring to form a ring.
(Substituent group X)
An alkyl group such as a methyl group, an ethyl group or a butyl group (preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms);
Cycloalkyl groups such as cyclopentyl group and cyclohexyl group (preferably a cycloalkyl group having 3 to 12 carbon atoms, more preferably 5 to 8 carbon atoms).
An alkenyl group such as a vinyl group (preferably an alkenyl group having 2 to 11 carbon atoms, more preferably 2 to 5 carbon atoms);
An alkynyl group such as an ethynyl group (preferably an alkynyl group having 2 to 11 carbon atoms, more preferably 2 to 5 carbon atoms);
Alkoxy groups such as methoxy and ethoxy groups (preferably having 1 to 10 carbon atoms, more preferably having 1 to 6 carbon atoms);
Aryloxy groups such as phenoxy group, naphthoxy group and pyridyloxy group (preferably an aryloxy group having 4 to 25 carbon atoms, more preferably 5 to 14 carbon atoms);
Alkoxycarbonyl groups such as methoxycarbonyl group and ethoxycarbonyl group (preferably having 2 to 11 carbon atoms, more preferably having 2 to 7 carbon atoms);
A dialkylamino group such as a dimethylamino group or a diethylamino group (preferably a dialkylamino group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms);
A diarylamino group such as a diphenylamino group, a ditolylamino group, or an N-carbazolyl group (preferably a diarylamino group having 10 to 30 carbon atoms, more preferably 12 to 22 carbon atoms);

An arylalkylamino group such as a phenylmethylamino group (preferably an arylalkylamino group having 6 to 25 carbon atoms, more preferably 7 to 17 carbon atoms);
An acyl group such as an acetyl group or a benzoyl group (preferably an acyl group having 2 to 10 carbon atoms, preferably 2 to 7 carbon atoms);
Halogen atoms such as fluorine atoms and chlorine atoms;
A haloalkyl group such as a trifluoromethyl group (preferably a haloalkyl group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms);
An alkylthio group such as a methylthio group and an ethylthio group (preferably an alkylthio group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms);
Arylthio groups such as phenylthio group, naphthylthio group and pyridylthio group (preferably an arylthio group having 4 to 25 carbon atoms, more preferably 5 to 14 carbon atoms);
A silyl group such as a trimethylsilyl group or a triphenylsilyl group (preferably a silyl group having 2 to 33 carbon atoms, more preferably a silyl group having 3 to 26 carbon atoms);
A siloxy group such as a trimethylsiloxy group or a triphenylsiloxy group (preferably a C2-C33, more preferably a C3-C26 siloxy group);
A cyano group;
An aromatic hydrocarbon group such as a phenyl group or a naphthyl group (preferably an aromatic hydrocarbon ring group having 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms);
Aromatic heterocyclic group such as thienyl group and pyridyl group (preferably an aromatic heterocyclic group having 3 to 28 carbon atoms, more preferably 4 to 17 carbon atoms)
These substituents may further have a substituent, and examples of the substituent include the groups described in Substituent Group X.

(Molecular weight)
The molecular weight of the organic compound of the present invention is preferably 5000 or less, and more preferably 3000 or less. If the molecular weight of the organic compound exceeds this upper limit, it will be difficult to remove the impurity components, the vaporization temperature will rise, making it difficult to form a film by the vapor deposition method, or the solubility will be reduced to form a film by a wet method. There is a risk of trouble, which is not preferable. Further, the molecular weight of the organic compound is preferably 300 or more, and more preferably 500 or more. If the molecular weight of the organic compound is below this lower limit, the heat resistance is lowered, the practicality is limited, the vaporization temperature is lowered and the film formation by the vapor deposition method becomes difficult, the film quality in the film formation by the wet method There is a risk that it may be hindered by a decrease, etc., which is not preferable.
(Ar)
In formula (I), Ar represents an aryl group which may have a substituent. Two Ar in the formula (I) may be the same or different.

Examples of the aryl group include an aromatic hydrocarbon group and an aromatic heterocyclic group.
Examples of aromatic hydrocarbon groups include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, and fluoranthene ring. Examples thereof include monovalent groups derived from a single ring of a member ring or 2 to 5 condensed rings.

  Examples of aromatic heterocyclic groups include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole Ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring Quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. Reason The include monovalent groups.

Among these, Ar is preferably a phenyl group (a monovalent group derived from a benzene ring).
Ar may have a substituent. Examples of the substituent include those described in the above substituent group X.
The molecular weight of Ar, including its substituents, is preferably 500 or less, and more preferably 200 or less.
(Z)
Z represents a direct bond or an arylene group. Examples of the arylene group include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. Specific examples of the aromatic hydrocarbon group and the aromatic heterocyclic group include the divalent groups of the aromatic hydrocarbon group and the aromatic heterocyclic group exemplified as Ar.

Z is preferably a direct bond, p-phenylene group, m-phenylene group or biphenylene group, and particularly preferably a direct bond.
The arylene group may have a substituent, and examples of the substituent include the groups described in the substituent group X. Preferably, the arylene group is unsubstituted.
The molecular weight of Z including the substituent is preferably 500 or less, and more preferably 200 or less.
(Formula II)
The organic compound represented by the formula (I) is preferably represented by the following formula (II).

In the formula (II), the phenyl group substituted at the 2-position, 4-position and 6-position of the pyridine ring may have a substituent. Examples of the substituent include groups described in the substituent group X.
Z and Ar are as defined in formula (I).
(Formula III)
Furthermore, the organic compound represented by the formula (II) is preferably represented by the following formula (III).

In the formula, R _{1 to} R ₄ may have an alkyl group, a cycloalkyl group, an aryl group which may have a substituent, an alkoxy group which may have a substituent, or a substituent. Represents an aryloxy group. n represents an integer of 0 to 5. N representing the number of R _{1 to} R ₄ may be the same or different.
Specific examples of the alkyl group, cycloalkyl group, aryl group, alkoxy group and aryloxy group include specific examples of each group exemplified in the substituent group X. The aryl group represents an aromatic hydrocarbon group and an aromatic heterocyclic group.

  The aryl group, alkoxy group and aryloxy group may have a substituent, and examples of the substituent include the groups described in the substituent group X.

  Hereinafter, although the preferable example of the organic compound of this invention is given, this invention is not limited to the following compounds.

(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.
(1) As a method for introducing a pyridine ring, the following methods A) to C) can be employed.

A) When R ^a — (CHO) is used as ^a raw material (where R ^a represents an arbitrary substituent or linking group), the following methods 1) to 5) may be employed.
1) Angew. Chem. Int. Ed. Engl. (1962) 1,626, Synthesis (1976), 1-24, J. Heterocyclic Chem. (1977) 14, 147, Collect.Czech. Chem. Commun. 57 (1992) 2,385- 392 and CS-262585, etc., 1 equivalent of aldehyde and 0.5 to 2 equivalents of acetylide in the presence of a strong acid such as sulfuric acid, acetic acid, alcohol, nitrobenzene, toluene, chlorobenzene, dichlorobenzene, Stirring for 1 to 10 hours at room temperature alone or in a mixed solvent such as cyclohexane, or stirring for 1 to 10 hours under heating in an alcohol and / or water solvent in the presence of a strong base such as sodium hydroxide, An intermediate (-CH = CR-CO-) is obtained and synthesized by reacting an acylpyridinium salt and ammonium acetate in an acetic acid solvent under heating conditions in the presence of oxygen.

2) Liebigs Ann. Chem. (1974), 1415-1422, J. Org. Chem. 38, (2002) 6,830-832 and JP-A-2
In the presence of an oxidizing agent such as boron trifluoride or perchloric acid, aldehyde and acetylide are reacted in a toluene solvent under heating conditions to form a pyrylium salt, which is disclosed in To react with ammonia in alcohol solvent

  3) Ammonium acetate is used under heating conditions in a single or mixed solvent such as acetic acid, alcohol, nitrobenzene, toluene, chlorobenzene, dichlorobenzene, cyclohexane, etc. disclosed in J. Am. Chem. Soc. (1952) 74,200, etc. A one-step synthesis from aldehyde and acetylide

4) In a mortar, aldehyde and 2 equivalents of acetylide are used in the presence of a strong base such as sodium hydroxide as disclosed in Chem. Commun. (Cambridge) (2000) 22,2199-2200, without solvent, at room temperature. A method of synthesizing an intermediate (diketone) by mixing with acetic acid, alcohol, nitrobenzene, toluene, chlorobenzene, dichlorobenzene, cyclohexane, etc. alone or in a mixed solvent by reacting with ammonium acetate under heating conditions,

5) A method of synthesizing in one step from aldehyde and ethylidene vinylamine as disclosed in J. Org. Chem. (1988), 53, 5960, etc.

B) When a pyridine ring in which a halogen atom such as chlorine, bromine or iodine is substituted in at least one of the 2,4,6-positions is used as a raw material, the halogen element can be converted into an arbitrary substituent.
For example, there is a method disclosed in Org. Lett. 3 (2001) 26, 4263-4265, etc., and a method of synthesizing zinc bromide or boronic acid under heating conditions in the presence of a palladium catalyst (in the following, dba is dibenzylideneacetone).

C) In addition, in introducing various substituents, known methods can be arbitrarily applied as necessary. For example, the following 1) to 3) can be employed.
1) Using a paraformaldehyde as an aldehyde and an aromatic acyl compound as an acetylide, a pyridine having an aromatic ring group at the 2,6-position was synthesized, and this was synthesized using a halogenating agent such as N-bromosuccinimide. Halogenated at the -position to obtain a halogen compound, and a method in which the halogen atom is converted to -B (OH) ₂ group, -ZnCl group or -MgBr group, and the halogen compound is synthesized by a coupling reaction 2 ) After lithiation with n-butyllithium or the like, the halogen compound is treated with N, N-dimethylformamide to have an aromatic ring group at the 2,6-position and a -CHO group at the 4-position. Method of synthesizing pyridine and then reacting with acetylide to synthesize a second pyridine ring 3) 2,6-dichloro-4-iodopi 2,6,2 ′, 6′-tetrachloro- [4,4 ′] bipyridyl was synthesized by heating and stirring gin at 150 to 250 ° C. using a copper catalyst such as copper powder in the presence of a base. A method of synthesizing this by treating in the same manner as in the above B). For the aldehyde (R ^a -CHO) used in the synthesis method, a commonly available reagent can be used as appropriate, but if necessary, It can be easily synthesized by the following methods 1) to 13).

1) For example, a halide (R ^a -X) or a hydrocarbon compound having an active hydrogen atom (R ^a -H) such as alkyl lithium such as butyl lithium, sodium hydride, triethylamine, tert-butoxy potassium, sodium hydroxide, etc. A method of treating with a strong base (preferably alkyllithium such as butyllithium) and then treating with N, N-dimethylformamide (Organic & Biomolecular Chemistry (2003) 1,7,1157-1170; Tetrahedron Lett. 42 (2001) 37) , 6589-6592)
2) A —CO ₂ R group (R is a hydrogen atom, a chlorine atom, an alkyl group, an aromatic ring group, an amino group) is reduced with lithium aluminum hydride, sodium borohydride, etc., and after alcoholation, pyridinium chlorochromate, dioxide Oxidation with manganese, iodooxybenzoic acid, peroxodisulfate, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, etc. to form —CHO (J. Med. Chem. 1990) 33, 2408-2412; Angew. Chem., Int. Ed. 40 (2001) 23,4395-4397; J. Am. Chem. Soc. (2002) 124, 10, 2245-58; J. Am. Chem. Soc. (1993) 115, 9, 3752-3759; J. Chem. Res., Synop. (2001) 7, 274-276; Synthesis (2001) 15, 2273-2276; Bull. Korean Chem. Soc. 20 (1999) ) 11,1373-1374; Arzneim.-Forsch. 47 (1997) 1,13-18; J. Org. Chem. 63 (1998) 16,5658-5661; J. Chem. Soc. Sec. C; Organic ( 1968) 6,630-632)

3) The —CO ₂ R group (R is a hydrogen atom, chlorine atom, alkyl group, aromatic ring group, amino group) is reduced with lithium tris (dialkylamino) aluminum hydride, sodium tris (dialkylamino) aluminum hydride, etc. -CHO method in stages (Bull. Korean Chem. Soc., 13 (1992) 6,670-676; Bull. Korean Chem. Soc., 12 (1991) 1,7-8; Org. Prep. Proced. Int. 24 (1992) 3, 335-337)
4) A method in which —CO ₂ R group (R is a hydrogen atom, chlorine atom, alkyl group, aromatic ring group, amino group) is converted to —CHO in one step in the presence of hydrogen and a palladium catalyst (Chem. Ber. (1959 ) 92,2532-2542; WO 00/12457; Bull.Chem.Soc.Jpn. (2001) 74,1803-1815)
5) A method in which the —CN group is reduced with lithium tris (dialkylamino) aluminum hydride and the like to form —CHO in one step (Bull. Korean Chem. Soc., 13 (1992) 6,670-676)
6) A method of directly converting to Ar-CHO by reacting Ar-CH ₃ group (Ar is an aromatic ring group) with o-Iodylbenzoic acid, Dess-Martin period-inane, Acetoxyiodosylbenzoic acid, etc. (J. Am. Chem. Soc. (2002) 124,10,2245-58)

7) Ar—CH ₃ group (Ar is an aromatic ring group) Ar—CH ₂ Br, Ar—CH ₂ OCH ₃
A method of converting to Ar—CH ₂ OH via COO, followed by oxidation with pyridinium chlorochromate, manganese dioxide, iodoxybenzoic acid, etc. to form —CHO (J. Org. Chem. (1993) 58,3582 -3585)
8) Method of synthesizing aryl carboxaldehyde by reacting 1-ethyl-1-arylallyl alcohol with Vilsmeier reagent (Indian Journal of Chemistry (1988) 27B, 213-216)
9) A method of synthesizing aryl carboxaldehyde by reacting 1,4-cyclohexadiene with Vilsmeier reagent (Synthesis (1987), 197-199; Synthesis (1985), 779-781)
10) After bromination of Ar-CH ₃ group (Ar is an aromatic ring group) using bromine, N-bromosuccinimide, etc. to make Ar-CH ₂ Br, 2-Nitropropane carboanion reagent, Hexamethylenetetramine, etc. are allowed to act on it. (Coll.Czech.Chem.Commun. (1996) 61,1464-1472; Chem.Eur.J. (1996) 2,12,1585-1595; J.Chem.Research (S) , (1999) 210-211
)

11) A method for obtaining aryl aldehydes (such as 1,3,5-triformylbenzene) from polymethinium salts (such as heptamethinium salts) (Collect.Czech.Chem.Commun. (1965) 30,53-60)
12) Method of obtaining 1,3,5-triformylbenzene by self-condensation of triformylmethane (Collect.Czech.Chem.Commun. (1962) 27,2464-2467)
13) A method in which Ar-CHBr ₂ group (Ar is an aromatic ring group) is converted to Ar-CHO by using dialkylamine (Bulletin de La Societe Chmique De France (1966) 9,2966-2971)
As the ketone (R ^c —CO—CH ₂ —R ^b ) used in the above synthesis method, a commonly available reagent can be used as appropriate. If necessary, the following methods 1) and 2) Etc. can be easily synthesized.

1) By treating the R ^c —CO ₂ R group (R is a hydrogen atom, chlorine atom, alkyl group, aromatic ring group, amino group) with various alkylating agents (alkyl lithium, dimethyl sulfate, dimethyl sulfoxide, etc.), R ^c —CO—CH ₂ R ^b conversion method (J. Am. Chem. Soc. (1959), 81, 935-939; J. Am. Chem. Soc. (1961) 83,4668-; Tetrahedron Lett. (1967 1073-; J.Chem.Soc. (1960) 360-; J.Chem.Soc., Perkin Trans.1 (1977) 680; JP5-5062039)
2) Synthesis by reacting an acylating agent such as acid chloride in the presence of Lewis acid catalyst such as aluminum chloride (very common Friedel-Crafts reaction)
Other synthetic methods include "Heterocyclic Chemistry-Pharmaceutical Fundamentals" (2002, Kunieda et al., Chemical Dojinsha), "Heterocyclic Chemistry" (4th edition, 2000, JA Joule and K. Mills, Blackwell Science) ), “New edition of heterocyclic compounds, basic edition, applied edition” (2004, Hiroshi Yamanaka et al., Kodansha), “Under Borhard Shore Modern Organic Chemistry” (2004, KPCVollhardt, Kagaku Dojinsha), etc. It is also possible to use existing synthesis methods.

(2) As a method for introducing an N-carbazolyl group, for example, the following methods a) to c) can be employed as a method for introducing a carbazolyl group in the final step of synthesis.
a) A small excess of a halogenated aromatic boron compound such as fluorophenylboronic acid, difluorophenylboronic acid, fluorobiphenylboronic acid ester, pentafluorophenylboronic acid (0.7 to 0.7 to the halogen atom of the halide described later) Palladium catalyst such as tetrakis (triphenylphosphine) palladium and an aromatic di- or tri-substituted halide such as dibromofluorobenzene, diiodobenzene, tribromobenzene, trichlorotriazine and diiodobiphenyl. (About 0.1 to 10 mol%), in the presence of a base such as cesium carbonate, potassium phosphate, sodium carbonate (about 2 to 10 times equivalent to the halogen atom of the halide), toluene-ethanol, toluene-water , Tetrahydrofuran, diol , Dimethoxyethane, N, N-dimethylformamide, etc., or a mixed solvent system thereof (the boronic acid concentration is about 1 to 1000 mmol%), and heated to reflux in an inert gas atmosphere for about 5 to 24 hours. To form a basic skeleton having a fluorine atom as a substituent.

  Next, substituted or unsubstituted carbazole (about 1.1 to 10 equivalents relative to the fluorine atom on the basic skeleton having the fluorine atom as a substituent) under a dry gas atmosphere and / or an inert gas atmosphere, Strong bases such as sodium hydride, tert-butoxypotassium, n-butyllithium (N of azole compounds described later) in a temperature range of −78 to + 60 ° C. in a solvent such as tetrahydrofuran, dioxane, ether, N, N-dimethylformamide. A mixture obtained by stirring and reacting for 0.1 to 60 hours with respect to hydrogen, and a basic skeleton of tetrahydrofuran, dioxane, ether, N, , N-dimethylformamide and the like, and the mixture is stirred for 1 to 60 hours under reflux with heating, whereby the organication of the present invention is performed. It is possible to obtain a thing.

b) A small excess of halogenated aromatic boronic acid such as bromophenylboronic acid, dibromophenylboronic acid, dichlorophenylboronic acid (about 1.1 to 1.5 times equivalent to the halogen atom of the halide described later) A di- or tri-substituted halide such as diiodobenzene, bromodiiodobenzene, triiodobenzene, trichlorotriazine, or diiodobiphenyl and a palladium catalyst such as tetrakis (triphenylphosphine) palladium (based on the halogen atom of the halide). 0.01 to 1 equivalent), in the presence of a base such as cesium carbonate, potassium phosphate, sodium carbonate (about 2 to 10 equivalents relative to the halogen atom of the halide), toluene, ethanol, water, tetrahydrofuran, dioxane , Dimethoxyethane, N, N-di Such as chill formamide, or a mixed solvent system thereof (
The basic skeleton having a bromine atom and / or a chlorine atom as a substituent can be formed by heating and refluxing in an inert gas atmosphere for about 5 to 24 hours under an inert gas atmosphere. it can.

Furthermore, if necessary, from the basic skeleton having a bromine group, potassium iodide (1.5 to 10 equivalents relative to the bromine atom on the basic skeleton), copper iodide (1 to 10 equivalents) is present. Under stirring in a solvent such as N, N-dimethylformamide (the halide concentration is about 0.1 to 10 mol%) at 100 to 300 ° C. for 0.5 to 60 hours, the bromine group becomes an iodine group. A converted basic skeleton can be obtained.
Next, a basic skeleton having a bromine atom or / and a chlorine atom as a substituent and carbazole (1. with respect to a bromine atom and / or a chlorine atom on the basic skeleton having a bromine atom or / and a chlorine atom as a substituent). 0 to 100 equivalents)

(1) Copper powder, copper wire, copper halide (CuX ^a (X ^a = Cl, Br, I)), copper oxide (
CuO) and other copper catalysts (about 1 to 5 equivalents to bromine atoms and / or chlorine atoms on the basic skeleton having a bromine atom and / or chlorine atom as a substituent), in an inert gas stream, no In a solvent or a solvent such as tetraglyme and polyethylene glycol (about 0.1 to 2 liters per 1 mol of the basic skeleton), the mixture is stirred and mixed at a temperature range of 20 to 300 ° C. for 1 to 60 hours,
(2) Pd ₂ (dba) ₃ (Pd = palladium, dba = dibenzylideneacetone),
Bivalent palladium catalyst such as Pd (dba) ₂ and palladium acetate, BINAP (= 2,2-bis (diphenylphosphino-1,1′-binaphthyl), tri (tert-butyl) phosphine, triphenylphosphine 1,2-bis (diphenylphosphino) ethane, 1,3-bis (diphenylphosphino) propane, 1,3-bis (diphenylphosphino) butane, dppf (= 1,1′-bis (diphenylphosphino) ) Ferrocene) or a combination of ligands such as Pd (PPh) ₄ (Ph = phenyl) or a palladium valent complex such as PdCl ₂ (dppf) ₂ (usually bromine) 0 for 1 equivalent of bromine atom and / or chlorine atom on the basic skeleton having an atom or / and chlorine atom as a substituent 0.01-1 equivalent) and, if necessary, strong bases such as tert-butoxypotassium, tert-butoxysodium, potassium carbonate, triethylamine (usually 1 equivalent to 1 equivalent of hydrogen halide that can be produced in the reaction). .1 to 10 equivalents) in the presence of a copper catalyst such as copper iodide (usually 1 to 10 equivalents relative to 1 equivalent of hydrogen halide that can be produced by the reaction) in the presence of tetrahydrofuran, dioxane, dimethoxy Solvents such as ethane, N, N-dimethylformamide, dimethyl sulfoxide, xylene, toluene, triethylamine (usually about 0.1 to 100 mmol% at the concentration of the basic skeleton having a bromine atom and / or chlorine atom as a substituent) The organic compound of the present invention can be obtained by, for example, stirring at 30 to 200 ° C. for 1 to 60 hours.

  c) In addition, for the coupling, known methods such as a Grignard reaction, a method using zinc, a method using tin, and the like can be applied. Examples of the catalyst used include palladium, nickel, and copper. A transition metal catalyst is mentioned, Usually, a catalyst is used about 0.1-200 mol% with respect to the intermediate body which has a carbazole ring. Examples of the basic substance include potassium carbonate, calcium carbonate, potassium phosphate, cesium carbonate, tert-butoxy sodium and the like. Usually, the basic substance is 50 to 1000 mol% with respect to the intermediate having a carbazole ring. Used to a degree. The reaction temperature is usually 0 ° C. or higher, preferably 50 ° C. or higher and 300 ° C. or lower, preferably 200 ° C. or lower. Examples of the solvent that can be used for the reaction include aromatic solvents such as toluene, xylene, and nitrobenzene, and ether solvents such as tetrahydrofuran, ethylene glycol dimethyl ether, and tetraglyme.

(5) As a method for introducing a 2-8-carbazolyl group, a coupling reaction of a carbazole having a halogen atom such as chlorine, bromine or iodine at a position where a linking group Z is linked with an aryl borate, or halogenation A coupling reaction between aryl and carbazolylborate can be used. Specifically, a known coupling method (“Palladium in Heterocyclic Chemistry: A guide for the Synthetic Chemist” (2nd edition, 2002, Jie Jack Li and Gordon W. Gribble, Pergamon), “Organic synthesis pioneered by transition metals, its various reaction forms and latest results” (1997, Junjiro, Kagaku Dojinsha), “Under Bolhardt Shore Modern Organic Chemistry” ( 2004, KPCVollhardt, Kagaku Dojinsha)) and the like can be used.

(6) Compound purification methods include “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 methods” (1988, ) Issued by IPC), or the methods described in the section “Separation and purification” in “Experimental Chemistry Course (4th edition) 1” (1990, edited by The Chemical Society of Japan) Is available. Specifically, extraction (including suspension washing, boiling washing, ultrasonic washing, acid-base washing), adsorption, occlusion, melting, crystallization (including recrystallization from solvent, reprecipitation), distillation (atmospheric pressure) Distillation, vacuum distillation), evaporation, sublimation (atmospheric pressure sublimation, vacuum sublimation), ion exchange, dialysis, filtration, ultrafiltration, reverse osmosis, pressure osmosis, zone lysis, electrophoresis, centrifugation, flotation separation, sedimentation separation, Magnetic separation, various chromatography (shape classification: column, paper, thin layer, capillary. Mobile phase classification: gas, liquid, micelle, supercritical fluid. Separation mechanism: adsorption, distribution, ion exchange, molecular sieve, chelate, gel filtration , Exclusion, affinity.).

(7) 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 chromatograph (GPC), cross-fractionation chromatograph (CFC) mass spectrometry (MS, LC / MS, GC / MS, MS / MS), nuclear magnetic resonance apparatus (NMR ( ¹ HNMR, ¹³ CNMR)) , Fourier transform infrared spectrophotometer (FT-IR), ultraviolet visible near infrared spectrophotometer (UV.VIS, NIR), electron spin resonance apparatus (ESR), transmission electron microscope (TEM-EDX), electron beam microanalyzer ( EPMA), metal element analysis (ion chromatography, inductively coupled plasma-emission spectroscopy (ICP-AES) atomic absorption) Analysis (AAS) X-ray fluorescence analyzer (XRF)), non-metallic element analysis, trace component analysis (ICP-MS, GF-AAS, GD-MS) and the like can be applied as necessary.

(Use of organic compounds)
Since the organic compound of the present invention has high charge transportability, it can be suitably used as an electrophotographic photosensitive member, an organic electroluminescent device, a photoelectric conversion device, an organic solar cell, an organic rectifying device and the like as a charge transport material.
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 can be obtained by using the charge transport material comprising the organic compound of the present invention. The organic compound and charge transport material of the present invention are particularly suitable as an organic electroluminescent element material.

<Charge transport material composition>
The charge transport material composition of the present invention contains the organic compound of the present invention described above, preferably a solvent, and is preferably used for an organic electroluminescent device. Moreover, the charge transport material composition of the present invention may further contain a light emitting material described in detail below.
[1] Solvent The solvent contained in the charge transport material composition of the present invention is not particularly limited as long as it is a solvent in which the charge transport material of the present invention which is a solute dissolves well.

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

Since organic electroluminescent devices use many materials such as cathodes that deteriorate significantly due to moisture, the presence of moisture in the composition causes moisture to remain in the dried film, degrading the device characteristics. The possibility is considered and it is not preferable.
Examples of the method for reducing the amount of water in the composition include nitrogen gas sealing, use of a desiccant, dehydration of the solvent in advance, use of a solvent having low water solubility, and the like. In particular, it is preferable to use a solvent having low water solubility because the solution film can prevent whitening by absorbing moisture in the atmosphere during the wet film-forming process. From such a viewpoint, the charge transport material composition to which the present embodiment is applied includes, for example, a solvent having a water solubility at 25 ° C. of 1% by weight or less, preferably 0.1% by weight or less. It is preferable to contain 10% by weight or more in the product.

Further, in order to reduce deterioration in film formation stability due to solvent evaporation from the composition during wet film formation, the solvent of the charge transport material composition has a boiling point of 100 ° C. or higher, preferably 150 ° C. or higher. More preferably, it is 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-mentioned conditions, ie, solute solubility, evaporation rate, and water solubility conditions, may be used alone. However, if a solvent that satisfies all the conditions cannot be selected, two or more solvents may be mixed. It can also be used.

<Organic electroluminescent device>
The organic electroluminescent element 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 organic compound of the present invention. . In particular, the layer containing the organic compound of the present invention is preferably a light emitting layer.
1 to 7 are schematic cross-sectional views showing structural examples suitable for the organic electroluminescence device of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a light emitting layer, 5 represents an electron injection layer, and 6 represents a cathode.

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

[2] Anode An anode 2 is provided on the substrate 1. The anode 2 plays a role of hole injection into a layer on the light emitting layer side (such as the hole injection layer 3 or the light emitting layer 4).
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or A conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline is used.

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

The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.
The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.
The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.

[3] Hole Injection Layer Since the hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 4, the hole injection layer 3 preferably contains a hole transporting compound.
In the hole injection layer 3, a cation radical obtained by removing one electron from an electrically neutral compound accepts one electron from a nearby electrically neutral compound, whereby holes move. When the cation radical compound is not included in the hole injection layer 3 when the element is not energized, the cation radical of the hole transport compound is generated when the hole transport compound gives electrons to the anode 2 during energization, Holes are transported by transferring electrons between the cation radical and an electrically neutral hole transporting compound.

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

Here, the cation radical compound is a cation radical that is a chemical species obtained by removing one electron from a hole transporting compound, and an ionic compound composed of a counter anion, and already has holes (free carriers) that are easy to move. Yes.
Further, by mixing an electron-accepting compound with the hole-transporting compound, one-electron transfer from the hole-transporting compound to the electron-accepting compound occurs, and the above-described cation radical compound is generated. For this reason, it is preferable that the hole injection layer 3 contains a hole transporting compound and an electron accepting compound.

Summarizing the above preferred materials, the hole injection layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. The hole injection layer 3 preferably contains a cation radical compound, and more preferably contains a cation radical compound and a hole transporting compound.
Furthermore, the hole injection layer 3 may contain a binder resin that does not easily trap charges and a coating property improving agent as necessary.

  However, as the hole injection layer 3, it is also possible to form only the electron-accepting compound on the anode 2 by a wet film-forming method, and directly apply and laminate the charge transport material composition of the present invention from the film. is there. In this case, when a part of the charge transport material composition of the present invention interacts with the electron accepting compound, a layer excellent in hole injecting property is formed.

(Hole transporting compound)
As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable.
Examples of the hole transporting compound include an aromatic amine compound, a phthalocyanine derivative, a porphyrin derivative, an oligothiophene derivative, a polythiophene derivative and the like in addition to the charge transport material of the present invention. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness and visible light transmittance.
Of the aromatic amine compounds, aromatic tertiary amine compounds 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 kind 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 (polymerized hydrocarbon 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).

(In the general formula (VII), Ar ²¹ and Ar ²² each independently represents an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Each of Ar ^{23 to} Ar ²⁵ 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.)

(In the above formulas, Ar ^{31 to} Ar ⁴¹ are each independently an aromatic hydrocarbon ring optionally having a substituent or an aromatic heterocyclic ring optionally having a substituent. R ³¹ and R ³² each independently represents a hydrogen atom or an arbitrary substituent.))
As Ar ^{21 to} Ar ²⁵ and Ar ^{31 to} Ar ⁴¹ , a monovalent or divalent group derived from any aromatic hydrocarbon ring or aromatic heterocyclic ring is applicable. These may be the same or different from each other. Moreover, you may have arbitrary substituents.

Examples of the aromatic hydrocarbon ring include a 5- or 6-membered monocyclic ring or a 2-5 condensed ring. Specific examples include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring and the like.
The aromatic heterocycle includes a 5- or 6-membered monocyclic ring or a 2-4 condensed ring. Specific examples include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Synoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring and the like.

In addition, Ar ^{23 to} Ar ²⁵ , Ar ^{31 to} Ar ³⁵ , and Ar ^{37 to} Ar ⁴⁰ may be a divalent group derived from one or more of the aromatic hydrocarbon rings and / or aromatic heterocycles exemplified above. Two or more groups may be linked and used.
The group derived from the aromatic hydrocarbon ring and / or aromatic heterocycle of Ar ^{21 to} Ar ⁴¹ may further have a substituent. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. The type of the substituent is not particularly limited, and examples thereof include one or more selected from the following substituent group W.

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

Ar ²¹ and Ar ²² are preferably monovalent groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring from the viewpoint of the solubility, heat resistance, and hole injection / transport properties of the polymer compound. More preferred are a phenyl group and a naphthyl group.
Ar ^{23 to} Ar ²⁵ are preferably divalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring from the viewpoint of heat resistance and hole injection / transport properties including redox potential. More preferably a group, a biphenylene group, or a naphthylene group.

As R ³¹ and R ³² , a hydrogen atom or an arbitrary substituent can be applied. These may be the same or different from each other. The type of the substituent is not particularly limited, and examples of applicable substituents include alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, silyl groups, siloxy groups, aromatic hydrocarbon groups, aromatic heterocyclic rings. Group and halogen atom. Specific examples thereof include the groups exemplified in the above substituent group W.

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).

(In the general formulas (VIII) and (IX), Ar ⁴⁵ , Ar ⁴⁷ and Ar ⁴⁸ are each independently an aromatic hydrocarbon group which may have a substituent or a substituent. Each of Ar ⁴⁴ and Ar ⁴⁶ independently represents a divalent aromatic hydrocarbon group which may have a substituent, or a divalent which may have a substituent; In addition, among Ar ^{45 to} Ar ⁴⁸ , two groups bonded to the same N atom may be bonded to each other to form a ring, and R ^{41 to} R ⁴³ are each independently And represents a hydrogen atom or an arbitrary substituent.)
Specific examples of Ar ⁴⁵ , Ar ⁴⁷ , Ar ⁴⁸ and Ar ⁴⁴ , Ar ⁴⁶ , preferred examples, examples of substituents that may be included, and examples of preferred substituents are Ar ²¹ , Ar ²² and Ar ²³ to Ar respectively. Same as Ar ²⁵ . R ^{41 to} R ⁴³ are preferably a hydrogen atom or a substituent described in [Substituent group W], and more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, It is an aromatic hydrocarbon group.

Specific examples of the aromatic tertiary amine polymer compound containing a repeating unit represented by the general formula (VIII) and / or (IX) include those described in WO2005 / 089024, and preferred examples thereof are also included. Although it is the same, it is not limited to them at all.
Moreover, when forming a positive hole injection layer with a wet film forming method, the positive hole transport compound which is easy to melt | dissolve in a various solvent is preferable. As the aromatic tertiary amine compound, for example, a binaphthyl compound (Japanese Patent Laid-Open No. 2004-014187) and an asymmetric 1,4-phenylenediamine compound (Japanese Patent Laid-Open No. 2004-026732) are preferable.

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

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

Further, preferred specific examples of the oligothiophene derivative applicable as the hole transporting compound of the hole injection layer include α-terthiophene and its derivatives, α-sexithiophene and its derivatives, and oligothiophene containing a naphthalene ring. Derivatives (JP-A-6-256341) and the like.
Further, preferred specific examples of the polythiophene derivative applicable as the hole transporting compound in the present invention include poly (3,4-ethylenedioxythiophene) (PEDOT), poly (3-hexylthiophene) and the like.

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

The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. When two or more hole transporting compounds are contained, the combination thereof is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or two other hole transporting compounds are used. It is preferable to use the above together.
(Electron-accepting compound)
The electron-accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the above-described hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more is preferable, and 5 eV or more. The compound which is the compound of these is further more preferable.

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

Of the above compounds, onium salts substituted with organic groups and high valent inorganic compounds are preferred because of their strong oxidizing power, and organic groups are substituted because they are soluble in various solvents and applicable to wet coating. Preferred are onium salts, cyano compounds, and aromatic boron compounds.
Specific examples of an onium salt substituted with an organic group, a cyano compound, and an aromatic boron compound suitable as an electron-accepting compound include those described in WO 2005/089024, and suitable examples thereof are also the same. Although the compound (A-2) represented by the following structural formula is mentioned, it is not limited to them at all.

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

The cation radical is preferably a chemical species obtained by removing one electron from the aforementioned compound in the hole transporting compound, and is preferably a chemical species obtained by removing one electron from a compound more preferable as the hole transporting compound. From the viewpoints of visible light transmittance, heat resistance, solubility, and the like.
The cation radical compound can be generated by mixing the hole transporting compound and the electron accepting compound. That is, by mixing the hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the cation radical and the counter anion of the hole transporting compound are included. A cation ion compound is formed.

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

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

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

  As the solvent used for the layer formation by the wet film forming method, any solvent can be used as long as it can dissolve the above-mentioned materials (hole transporting compound, electron accepting compound, cation radical compound). Is not particularly limited, but generates a deactivated substance or deactivated substance that may deactivate each material (hole transporting compound, electron accepting compound, cation radical compound) used in the hole injection layer The thing which does not contain is preferable. Specifically, the solvents described in JP 2005-93428 A and JP 2005-93427 A can be used.

In the case of forming a layer by vacuum deposition, one or more of the aforementioned materials (hole transporting compound, electron accepting compound, cation radical compound) are put in a crucible installed in a vacuum vessel ( If two or more materials are used, put them in each crucible), evacuate the vacuum vessel to about 10 ^-4 Pa with a suitable vacuum pump, and then heat the crucible (if two or more materials are used, each Heat the crucible) and evaporate by controlling the amount of evaporation (if more than one material is used, evaporate by controlling the amount of evaporation independently) and place it positively on the anode of the substrate placed facing the crucible A hole injection layer is formed. In addition, when using 2 or more types of materials, they can also be put into a crucible, can be heated and evaporated, and can be used for hole injection layer formation.
The film thickness of the hole injection layer 3 thus formed is usually in the range of 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
The hole injection layer 3 may be omitted as shown in FIG.

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

Here, as described above, the wet film forming method is a method in which a composition containing a solvent is formed by spin coating, spray coating, dip coating, die coating, flexographic printing, screen printing, an ink jet method, or the like.
In the case of the wet film-forming method, the host material and the light-emitting material, and if necessary, additives such as a binder resin that does not become an electron trap or a light-quenching quencher, and a coating property improving agent such as a leveling agent were added and dissolved. The light-emitting layer 5 is formed by preparing a coating solution, applying the solution by a method such as spin coating, and drying. Examples of the binder resin include polycarbonate, polyarylate, and polyester. When the amount of the binder resin added is large, the hole / electron mobility is lowered. Therefore, the smaller amount is desirable, and 50% by weight or less is preferable.

In the case of the vacuum deposition method, the host material is put in a crucible installed in a vacuum vessel, the dye to be doped is put in another crucible, and the inside of the vacuum vessel is 1.0 × 10 ⁻⁴ Torr with an appropriate vacuum pump. After evacuating to a degree, each crucible is heated and evaporated simultaneously to form a layer on the substrate placed opposite the crucible. As another method, a mixture of the above materials in a predetermined ratio may be evaporated using the same crucible.

When each said dopant is doped in a light emitting layer, although doped uniformly in the film thickness direction of a light emitting layer, there may exist concentration distribution in a film thickness direction. For example, it may be doped only in the vicinity of the interface with the hole transport layer, or conversely, it may be doped in the vicinity of the interface of the hole blocking layer.
The light emitting layer can also be formed by the same method as the hole transport layer described below.

(Luminescent material)
A light emitting material mainly refers to a component that emits light, and corresponds to a dopant component in an organic EL device.
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.
In order to improve the solubility in a solvent, it is also important to reduce the symmetry and rigidity of the light emitting material molecule or to introduce a lipophilic substituent such as an alkyl group.

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

Examples of the phosphorescent material include organometallic complexes containing a metal selected from Groups 7 to 11 of the periodic table.
Preferred examples of the metal in the phosphorescent organometallic complex containing a metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. Preferred examples of these organometallic complexes include compounds represented by the following general formula (V) or the following general 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.)

(In the general formula (VI), M ^d represents a metal, T represents carbon or nitrogen. R ^{92 to} R ⁹⁵ 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.

  L ′ is particularly preferably the following from the viewpoint of the stability of the complex.

In the partial structures of L and L ′, the ring A1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group, and these may have a substituent. Ring A2 represents a nitrogen-containing aromatic heterocyclic group, and these may have a substituent.
When the rings A1 and A2 have a substituent, preferred substituents include halogen atoms such as fluorine atoms; alkyl groups such as methyl groups and ethyl groups; alkenyl groups such as vinyl groups; methoxycarbonyl groups and ethoxycarbonyl groups. Alkoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; diarylamino groups such as diphenylamino groups; carbazolyl groups; An acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group; an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, and a phenanthyl group.

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

(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.

(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.)

(In the general formula (Vc), M ^c represents the same metal as M, w represents the valence of the metal, and j represents 0, 1 or 2. Further, ring A1 and ring A1 ′ represent Each independently represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and ring A2 and ring A2 ′ are each independently Represents a nitrogen-containing aromatic heterocyclic group which may have a substituent.
In the above general formulas (Va), (Vb), and (Vc), the group of ring A1 and ring A1 ′ is preferably, for example, phenyl group, biphenyl group, naphthyl group, anthryl group, thienyl group, furyl group, benzo Examples include thienyl group, benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group, carbazolyl group and the like.

In addition, the group of ring A2 and ring A2 ′ is preferably a pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, isoquinolyl group, quinoxalyl group, A phenanthridyl group and the like can be mentioned.
Furthermore, the substituents that the compounds represented by the general formulas (Va), (Vb), and (Vc) may have include a halogen atom such as a fluorine atom; an alkyl group such as a methyl group and an ethyl group; vinyl Alkenyl groups such as methoxy groups; alkoxycarbonyl groups such as methoxycarbonyl groups and ethoxycarbonyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups and benzyloxy groups; dialkyls such as dimethylamino groups and diethylamino groups An amino group; a diarylamino group such as a diphenylamino group; a carbazolyl group; an acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group;

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

These substituents may be connected to each other to form a ring. As a specific example, a substituent of the ring A1 and a substituent of the ring A2 are bonded, or a substituent of the ring A1 ′ and a substituent of the ring A2 ′ are bonded. Two fused rings may be formed. Examples of such a condensed ring group include a 7,8-benzoquinoline group.
Among them, as a substituent of ring A1, ring A1 ′, ring A2 and ring A2 ′, more preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group, a cyano group, a halogen atom, a haloalkyl group, a diarylamino group, a carbazolyl group Is mentioned.

Further, Ma, Mb, and Mc in the general formulas (Va), (Vb), and (Vc) are preferably ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold.
Specific examples of the organometallic complex represented by the general formula (V), (Va), (Vb) or (Vc) are shown below, but are not limited to the following compounds (in the following, Ph is phenyl Represents a group).

Among the organometallic complexes represented by the general formulas (V), (Va), (Vb), and (Vc), in particular, as the ligand L and / or L ′, a 2-arylpyridine-based ligand, , 2-arylpyridine, a compound having an arbitrary substituent bonded thereto, and a compound having an arbitrary group condensed thereto are preferable.
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 are each independently a hydrogen atom, halogen atom, alkyl group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group. Represents an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group.

Further, when T is carbon, R ⁹⁴ and R ⁹⁵ each independently represent a substituent represented by the same examples as R ⁹² and R ⁹³ . Further, as described above, when T is nitrogen, R ⁹⁴ and R ⁹⁵ are absent.
R ^{92 to} R ⁹⁵ may further have a substituent. In this case, the substituent which may further be present is not particularly limited, and any group can be used as the substituent.

Furthermore, R ^{92 to} R ⁹⁵ may be linked to each other to form a ring, and this ring is further substituted with an arbitrary substituted general formula (VI). Specific examples of organometallic complexes (T-1, T-10) -T-15) is shown below, but is not limited to the following exemplified compounds. In the following, Me represents a methyl group, and Et represents an ethyl group.

Moreover, as an organometallic complex, the compounds described in WO2005 / 019373 can also be used.
In addition, the light emitting layer 4 may contain other materials and components as long as the performance of the present invention is not impaired.
In general, when the same material is used in the organic electroluminescent element, the thinner the film thickness between the electrodes, the larger the effective electric field, so that the injected current increases, so the driving voltage decreases. For this reason, the driving voltage of the organic electroluminescence device decreases when the total film thickness between the electrodes is thin, but if it is too thin, a short circuit occurs due to the protrusion caused by the electrode such as ITO. Necessary.

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

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

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

The film thickness of the electron injection layer 5 is preferably 0.1 to 5 nm.
Also, an ultrathin insulating film (0.1 to 5 nm) such as LiF, MgF ₂ , Li ₂ O, Cs ₂ CO ₃ may be inserted at the interface between the cathode 6 and the light emitting layer 4 or the electron transport layer 8 described later. This is an effective method for improving the efficiency of the device (Appl. Phys. Lett., 70, 152, 1997; JP-A-10-7).
No. 4586; IEEE Trans. Electron. Devices, 44, 1245, 1997; SID 04 Digest, 154).

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

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

The alkali metal is deposited using an alkali metal dispenser in which nichrome is filled with an alkali metal chromate and a reducing agent. By heating the dispenser in a vacuum container, the alkali metal chromate is reduced and the alkali metal is evaporated. When co-depositing an organic electron transport material and an alkali metal, after placing the organic electron transport material in a crucible installed in a vacuum vessel and evacuating the vacuum vessel to about 10 ⁻⁴ Pa with an appropriate vacuum pump Each crucible and dispenser are heated simultaneously to evaporate to form an electron injection layer on the substrate placed facing the crucible and dispenser.
At this time, co-evaporation is uniformly performed in the film thickness direction of the electron injection layer 5, but there may be a concentration distribution in the film thickness direction.
The electron injection layer 5 may be omitted as shown in FIGS.

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

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

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

Examples of the layer that may be included include the electron transport layer 7. The electron transport layer 7 is provided between the light emitting layer 4 and the electron injection layer 5 as shown in FIG. 2 for the purpose of further improving the light emission efficiency of the device.
The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 6 between electrodes to which an electric field is applied in the direction of the light emitting layer 4. As an electron transport compound used for the electron transport layer 7, the electron injection efficiency from the cathode 6 or the electron injection layer 5 is high, and the injected electrons can be efficiently transported with high electron mobility. It must be a compound.

  Materials satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives, Styryl biphenyl derivative, silole derivative, 3- or 5-hydroxyflavone metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compound No. 207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide, n-type sulfide Examples include zinc and n-type zinc selenide.

The lower limit of the thickness of the electron transport layer 7 is usually 1 nm, preferably about 5 nm, and the upper limit is usually about 300 nm, preferably about 100 nm.
The electron transport layer 7 is formed by laminating on the light emitting layer 4 by a wet film forming method or a vacuum deposition method in the same manner as the hole injection layer 3. Usually, a vacuum deposition method is used.
In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting substance, it is also effective to provide the hole blocking layer 8 as shown in FIGS. 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, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high.

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

Furthermore, a compound having at least one pyridine ring substituted at the 2,4,6-positions described in WO2005 / 022962 is also preferable as the hole blocking material.
The film thickness of the hole blocking layer 8 is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.
The hole blocking layer 8 can also be formed by the same method as the hole injection layer 3, but a vacuum deposition method is usually used.

The electron transport layer 7 and the hole blocking layer 8 may be appropriately provided as necessary. 1) Only the electron transport layer, 2) Only the hole blocking layer, 3) Lamination of the hole blocking layer / electron transport layer, 4) There are usages such as not using.
For the same purpose as the hole blocking layer 8, it is also effective to provide an electron blocking layer 9 between the hole injection layer 3 and the light emitting layer 4 as shown in FIG. The electron blocking layer 9 increases the probability of recombination with holes in the light emitting layer 4 by blocking the electrons moving from the light emitting layer 4 from reaching the hole injection layer 3, thereby generating excitons generated. Has a role of confining the light in the light emitting layer 4 and a role of efficiently transporting holes injected from the hole injection layer 3 in the direction of the light emitting layer 4.

The characteristics required for the electron blocking layer 9 include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Further, when the light emitting layer 4 is formed by a wet film forming method, it is preferable that the electron blocking layer 9 is also formed by a wet film forming method because the device manufacturing becomes easy.
For this reason, it is preferable that the electron blocking layer 9 also has wet film forming compatibility, and examples of the material used for such an electron blocking layer 9 include dioctyl typified by F8-TFB in addition to the charge transport material of the present invention. And a copolymer of fluorene and triphenylamine (described in WO 2004/084260).

  Further, as shown in FIG. 8, a hole transport layer may be provided between the light emitting layer and the anode. As conditions required for the material of the hole transport layer, it is necessary that the material has a high hole injection efficiency from the anode and can efficiently transport the injected holes. For this purpose, the ionization potential is small, the transparency to visible light is high, the hole mobility is high, the stability is high, and impurities that become traps are less likely to be generated during manufacturing and 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 or to form an exciplex with the light emitting layer 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. Therefore, a material having a Tg value of 85 ° C. or higher is desirable.

  Examples of such a hole transport material include two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl, and two or more Aromatics having a starburst structure such as aromatic diamines in which condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4 ', 4'-tris (1-naphthylphenylamino) triphenylamine Group amine compounds (J. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 Spiro compounds such as', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, 91, 209, 1 Like 97 years), and the like. These compounds may be used alone or in combination as necessary. In addition to the above compounds, polyarylene ether sulfone (Polym. Adv. Tech., Which contains polyvinyl carbazole, polyvinyl triphenylamine (JP-A-7-53953), and tetraphenylbenzidine as materials for the hole transport layer. 7 (page 33, 1996).

The hole transport layer is formed by a normal coating method such as a spray method, a printing method, a spin coating method, a dip coating method, or a die coating method, a wet film forming method such as an ink-jet method or a screen printing method, or a vacuum deposition method. It can be formed by a dry film forming method such as a method.
In the case of the coating method, one or more hole transport materials are added, and if necessary, additives such as binder resins and coating property improving agents that do not trap holes are added and dissolved in a suitable solvent. A solution is prepared, applied onto the anode 2 by a method such as spin coating, and dried to form the hole transport layer 4. Examples of the binder resin include polycarbonate, polyarylate, and polyester. When the binder resin is added in a large amount, the hole mobility is lowered.

In the case of the vacuum evaporation method, the hole transport material is put in a crucible installed in a vacuum vessel, the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with a suitable vacuum pump, and then the crucible is heated, The hole transport material is evaporated and a hole transport layer 4 is formed on the substrate 1 on which the anode 2 is formed, which is placed facing the crucible.
The thickness of the hole transport layer is usually 5 nm or more, preferably 10 nm or more, and 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 structure opposite to that shown in FIG. 1, that is, the cathode 6, the electron injection layer 5, the light emitting layer 4, the hole injection layer 3, and the anode 2 can be laminated on the substrate 1 in this order. It is also possible to provide the organic electroluminescent element of the present invention between two substrates, at least one of which is highly transparent. Similarly, it is also possible to laminate in a structure opposite to the above-described respective layer configurations shown in FIGS.
Further, a structure in which a plurality of layers shown in FIG. 1 are stacked (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, for example, V ₂ O ₅ or the like is used as the charge generation layer (CGL) instead of the interfacial layer (between the light emitting units) (two layers when the anode is ITO and the cathode is Al). This is more preferable from the viewpoint of luminous efficiency and driving voltage.

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

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.
(Synthesis Example 1)

  3-Bromo-acetophenone (12.0 g) and phenylbenzaldehyde (10 g) were dissolved in acetic acid (78 ml), sulfuric acid (8.8 ml) was added dropwise, and the mixture was stirred at 35 ° C. or lower for 8 hours. After the reaction, crystals were precipitated and allowed to cool, then 80 ml of methanol and 50 ml of water were added to the system and stirred. After crystal filtration, the target product 1 (19.1 g) was obtained after drying by washing with 150 ml of methanol and drying.

Phenacylpyridinium bromide (11.5 g), the target product 1 obtained above (10 g), ammonium acetate (53.2 g), acetic acid (197 ml), N, N-dimethylformamide (130 ml) were heated under reflux for 9 hours. To the solution obtained by stirring, ethanol (50 ml) is added and stirred, and then the deposited precipitate is filtered, and the resulting crystals are heated to reflux with methanol (200 ml). Washing with heating under reflux was repeated several times, and after drying, the target product 2 (10.8 g) was obtained.

Dissolve 3,6-dibromocarbazole (8g) and phenylboronic acid (7.8g) in ethylene glycol dimethyl ether (80ml), degas an aqueous solution of potassium carbonate 13.6g in 40ml of water, and add it to the system. The inside is deaerated, purged with nitrogen, and heated and stirred. At an internal temperature of 60 ° C., tetrakis (triphenylphosphine) palladium (0) (1.42 g) is added, and the reaction is carried out for 9 hours under heating and reflux. After cooling, the mixture is concentrated, water and chloroform are added to the system, and the organic layer is extracted.
The organic layer is dried over magnesium sulfate, further concentrated and crystallized with methanol. Then, it refine | purified with column chromatography, recrystallized with methanol, and the target object 3 (3.2g) was obtained after drying.

Toluene (40 ml) is added to the target product 2 (1.96 g) and target product 3 (1.5 g) sodium-tert-butoxide (0.82 g) obtained above and stirred. Tris (dibenzylideneacetone) dipalladium (0) chloroform (0.07 g) is dissolved in toluene (8 ml), a solution to which tri-tert-butylphosphine (0.057 g) is added is added, and the mixture is reacted with heating under reflux for 8 hours. After completion of the reaction, the insoluble material was removed, concentrated, washed with washing, and then purified by column chromatography to obtain the desired product 4 (0.9 g). From DEI-MS (m / z = 700 (M +)), it was confirmed to be the target product 4. As a result of DSC measurement, the glass transition temperature (Tg) of this product was 130 ° C.
(Synthesis Example 2)

  To a mixture of 1,3-dibromobenzaldehyde (15 g), 4-ethylphenylboronic acid (25 g) and dimethoxyethane (150 ml) in a nitrogen stream, tetrakis (triphenylphosphine) palladium (3.86 g), 2M potassium carbonate Aqueous solution (115 ml) was sequentially added, and the mixture was stirred for 5 hours under reflux with heating. After adding brine to the resulting solution, extracting with toluene, adding anhydrous magnesium sulfate to the organic layer, stirring, filtering and concentrating, the resulting residue was purified by silica gel column chromatography, The target product 5 (9.14 g) was obtained.

  In an inert gas atmosphere, a solution of the target compound 5 (9.14 g) and m-bromoacetophenone (6.4 g) in acetic acid (30 mL) was heated to 50 ° C., and sulfuric acid (8.5 g) and acetic acid (20 mL) were added. Was added dropwise and stirred at 50 ° C. for 8 hours. The reaction mixture was poured into methanol, and the precipitated oil was separated by decantation, dissolved in methylene chloride, and washed with saturated aqueous sodium hydrogen carbonate. After drying over magnesium sulfate, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography to obtain the desired product 6 (10.7 g).

To a solution of ammonium acetate (8.48 g) and phenacylpyridinium bromide (3.06 g) in acetic acid (5 mL) -DMF (5 mL), target 6 (5.2 g) in acetic acid (5 mL) -DMF (5 mL) was added at room temperature. It was dripped at. The reaction mixture was stirred under reflux conditions for 8 hours, allowed to cool to room temperature, and poured into water. The precipitated crystals were separated by decantation, dissolved in methylene chloride, washed with a saturated aqueous sodium chloride solution and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the intended product 7 (3.9 g).

Under nitrogen atmosphere, tri (tertiarybutyl) phosphine (200 mg) was added to a toluene (40 mL) solution of di (benzylideneacetone) dichloropalladium / chloroform adduct (339 mg) at room temperature and stirred at 40 ° C. for 20 minutes to form a complex. I let you. Under an inert gas atmosphere, a toluene solution of the complex prepared previously in (40 mL) was added to a toluene solution of the target product 7 (5.2 g), diphenylcarbazole (3.1 g), and tertiary butoxy sodium (1.9 g). It was dripped at 40 ° C. The solution was warmed, stirred under reflux conditions for 8 hours, allowed to cool to room temperature, and then poured into water. The precipitated crystals were separated by decantation, dissolved in methylene chloride, washed with a saturated aqueous sodium chloride solution and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the desired product 8 (3.5 g). Mass spectrometry result (DEI method, M ⁺ ): From 833, it was confirmed to be the target product 8.
The glass transition temperature of this product was 132 ° C.

(Synthesis Example 3)

  An aqueous solution (81 mL) of potassium carbonate (22.3 g) was added to a solution of 3,6-dibromocarbazole (10.5 g), 4-butylphenylboronic acid (19.3 g) and dimethoxyethane (96 mL) to perform nitrogen substitution. Then, tetrakistriphenylphosphine palladium (2.2 g) was added and refluxed for 6 hours. The mixture was allowed to cool to room temperature, poured into water, and extracted with methylene chloride. After drying over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography. 4.8 g of the target product 9 was obtained.

In a nitrogen stream, target 2 (2.47 g), target 9 (1.8 g), copper powder (266 mg), potassium carbonate (1.16 g), and tetraglyme (5 ml) were added to a 100 ml four-necked flask at 200 ° C. The mixture was placed in an oil bath and stirred for 13 hours. Diluted with dichloromethane, filtered, washed with brine, dried over sodium sulfate, and evaporated under reduced pressure to give a brown oil. Purification by column chromatography and GPC gave the target product 10 (144 mg).
It was confirmed by DEI-MS m / z = 814 (M ⁺ ) that it was the target product. This had a glass transition temperature of 84 ° C., a melting point of 118 ° C., and a vaporization temperature of 507 ° C.
(Synthesis Example 4)

3-bromophenaldehyde (4.06g), 3-biphenylboronic acid (5.0g), dimethoxyethane (100ml)
An aqueous solution (33 mL) of potassium carbonate (9.1 g) was added to the solution, and the atmosphere was purged with nitrogen. Then, tetrakistriphenylphosphine palladium (1.0 g) was added and refluxed for 9 hours. The mixture was allowed to cool to room temperature, poured into water, and extracted with methylene chloride. After drying over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure and purified by silica gel column chromatography. 4.8 g of the target product 11 on oil was obtained.

A solution of the target compound 11 (4.8 g) and 3-bromoacetophenone (4.06 g) in acetic acid (28 g) and sulfuric acid (5.46 g) were added dropwise at room temperature, and the mixture was stirred at 30 ° C. for 8 hours. Methanol and water were poured into the reaction mixture, and the precipitated crystals were filtered. Washing with methanol gave the target product 12 (6.35 g).

The target compound 12 (6.0 g), 1-phenacylpyridine bromide (5.69 g), ammonium acetate (26.2 g), is dissolved in a mixed solution of acetic acid (97 ml) and dimethylformamide (70 ml) and stirred for 9 hours with heating under reflux. did.
After completion of the reaction, ethanol and water were added to the reaction mixture, and the resulting crystals were separated by filtration. After dissolving in toluene and washing with alkaline water, brine and water, the organic layer was dried over magnesium sulfate. The solvent was distilled off under reduced pressure, and after vacuum drying, 6.3 g of the oily target product 13 was obtained.

Toluene (80 ml) is added to the target product 13 (4 g) and target product 3 (2.85 g) sodium-tert-butoxide (1.43 g) obtained above and stirred. Tris (dibenzylideneacetone) dipalladium (0) chloroform (0.46 g) is dissolved in toluene (10 ml), a solution to which tri-tert-butylphosphine (0.45 g) is added is added, and the mixture is reacted under heating and reflux for 8 hours. After completion of the reaction, insolubles were removed, concentrated, washed with hanging, and purified by column chromatography to obtain the desired product 14 (4.15 g). From DEI-MS (m / z = 776 (M +)), it was confirmed to be the target product 14. As a result of DSC measurement, the glass transition temperature (Tg) of this product was 119 ° C.

Example 1
An organic electroluminescent element having the structure shown in FIG. 8 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film 2 deposited on a glass substrate 1 with a thickness of 150 nm (sputtered film; sheet resistance: 15Ω) is formed into a 2 mm wide stripe using ordinary photolithography and hydrochloric acid etching. An anode was formed by patterning. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.

  As a material for the hole injection layer 3, a non-conjugated polymer compound (PB-1) having an aromatic amino group having the structural formula shown below

（ＰＢ−１）

(PB-1)

Weight average molecular weight: 29400
Number average molecular weight: 12600
An electron-accepting compound (A-2)

（Ａ−２）

(A-2)

The mixture was mixed under the following conditions, followed by spin coating, temporary drying, and drying.
Spin coating conditions
Solvent ethyl benzoate
Coating solution concentration 2 [wt%]
PB-1: A-2 10: 2
Spinner speed 1500 [rpm]
Spinner rotation time 30 [seconds]
Dry
Temporary drying 80 [℃] 1 [min] on hot plate
Drying 230 [° C.] 15 [min] In an oven A uniform thin film having a thickness of 30 nm was formed through the spin coating, temporary drying, and drying steps described above.

Next, the substrate on which the hole injection layer 3 was formed was placed in a vacuum evaporation apparatus. After roughly exhausting the apparatus with an oil rotary pump, the apparatus was exhausted with a cryopump until the degree of vacuum in the apparatus was about 1.0 × 10 ⁻⁴ Pa or less. Arylamine compound (H-1) shown below, placed in a ceramic crucible placed in the above apparatus

（Ｈ−１）

(H-1)

Vapor deposition was performed by heating with a tantalum wire heater around the crucible. A hole transport layer 4 having a film thickness of 40 nm was obtained at a vacuum degree of 7.5 × 10 ⁻⁵ Pa and a vapor deposition rate of 0.10 to 0.15 nm / sec. The crucible temperature at this time was 266-276 ° C.
Subsequently, (E-1) shown below as a main component (host material) of the light-emitting layer 5 and an organic iridium complex (D-1) as a subcomponent (dopant) are placed in separate ceramic crucibles, and two-way simultaneous Film formation was performed by vapor deposition.

The temperature of the crucible (E-1) is 338 to 358 ° C., the deposition rate is 0.11 nm / second, and the compound (D-1
The temperature of the crucible was adjusted to 253-255 ° C., and the light emitting layer 5 containing 5.8% by weight of the compound (D-1) with a film thickness of 30 nm was laminated on the hole transport layer 10. The degree of vacuum at the time of deposition was 7.4 × 10 ⁻⁵ Pa.
Further, the compound (HB-1) shown below as the hole blocking layer 8

The crucible temperature was 233 to 238 ° C., and the film was laminated with a film thickness of 5 nm at a deposition rate of 0.09 nm / second. The degree of vacuum during the deposition was 6.4 × 10 ⁻⁵ Pa.
An aluminum 8-hydroxyquinoline complex (ET-1) shown below as an electron transport layer 7 on the hole blocking layer 8

Was deposited in the same manner. At this time, the crucible temperature of the aluminum 8-hydroxyquinoline complex is controlled in the range of 301 to 308 ° C, the vacuum during deposition is 6.4 × 10 ^-5 Pa, the deposition rate is 0.10 to 0.17 nm / sec, and the film thickness is 30 nm.
The substrate temperature when vacuum-depositing the hole transport layer, the light emitting layer, the hole blocking layer, and the electron transport layer was maintained at room temperature.

Here, the element on which the electron transport layer 7 has been deposited is once taken out from the vacuum deposition apparatus into the atmosphere, and a 2 mm wide striped shadow mask is used as the cathode deposition mask.
It was brought into close contact with the element so as to be orthogonal to the ITO stripe, placed in another vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus was 2.0 × 10 ⁻⁴ Pa or less in the same manner as the organic layer. Cathode 8
First, lithium fluoride (LiF) using a molybdenum boat, the deposition rate of 0.01nm /
Second, the degree of vacuum was 2.2 × 10 ⁻⁴ Pa, and a film thickness of 0.5 nm was formed on the electron transport layer 7. Next, aluminum was similarly heated by a molybdenum boat, the deposition rate was 0.1 to 0.4 nm / second, and the degree of vacuum was 5.0.
An aluminum layer having a thickness of 80 nm was formed at × 10 ⁻⁴ to 8.0 × 10 ⁻⁴ Pa to complete the cathode 6. The substrate temperature at the time of vapor deposition of the above two-layered cathode 6 was kept at room temperature.

Subsequently, in order to prevent the fabricated device from being deteriorated by moisture in the air during storage and characteristic tests, sealing treatment was performed by the method described below.
In a dry box filled with nitrogen, a photocurable resin (3124 manufactured by ThreeBond) is applied to the outer periphery of a 20 mm x 60 mm size glass plate with a width of about 1 mm, and a desiccant sheet in the center. (Getter dryer manufactured by SAES Getters) was installed. On this, the board | substrate which complete | finished cathode vapor deposition was bonded together so that the vapor-deposited surface might oppose a desiccant sheet. Then, only the area | region where the photocurable resin was apply | coated was irradiated with ultraviolet light, and resin was hardened.

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 shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² , and the luminance / current / voltage are values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device was 514 nm, which was identified as that from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.31,0.61). The drive lifetime at room temperature, the emission luminance at the start of energization to direct a constant current continuous energization at a constant current value to be 5000 cd / m ^2, a current time when the light emission luminance becomes 2500 cd / m ^2. The results are shown in Table-2. This device had a longer driving life than the device using CBP shown in Comparative Example 1 as the host material of the light emitting layer 5.

(Example 2)
An organic electroluminescent element having the structure shown in FIG. 8 was produced (however, the hole blocking layer 6 was not provided). An organic electroluminescent element having a light emitting area portion of 2 mm × 2 mm in size was obtained in the same manner as in Example 1 except that the hole blocking layer 6 was not laminated. The light emission characteristics of this element are shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² , and the luminance / current / voltage are values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device is 514 nm,
It was identified as from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.30,0.61). This element showed a higher luminance / current value than the element shown in Comparative Example 2 in which CBP was used as the host material of the light emitting layer 5 and the hole blocking layer 6 was not laminated.

(Example 3)
In the same manner as in Example 2 except that (E-2) shown below was used instead of (E-1) and (H-2) shown below was used instead of (H-1), 2 mm An organic electroluminescence device having a light emitting area portion of × 2 mm in size was obtained. The light emission characteristics of this element are shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² , and the luminance / current / voltage are values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device is 512 nm, and the organic iridium complex (D
-1). The chromaticity was CIE (x, y) = (0.30,0.62). The drive life is the energization time when the constant current of DC constant current is applied at a constant current value of 5000 cd / m ² at the start of energization and the light emission brightness reaches 2500 cd / m ² at room temperature. . The results are shown in Table-2.

  This device showed a higher luminance / current value than the device shown in Comparative Example 3 in which CBP was used as the host material of the light emitting layer 5 and the hole blocking layer 6 was not laminated.

(Comparative Example 1)
An organic electroluminescent device having a light emitting area portion of 2 mm × 2 mm in size was obtained in the same manner as in Example 1 except that (CBP) shown below was used instead of (E-1). . The light emission characteristics of this element are shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² ,
Luminance / current / voltage indicate values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device was 514 nm, which was identified as that from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.30,0.62). The drive lifetime at room temperature, a constant DC current is continuously energized with a constant current emission luminance at the start of energization is 5000 cd / m ^2, a current time when the light emission luminance becomes 2500 cd / m ^2. The results are shown in Table-2.

（ＣＢＰ）

(CBP)

(Comparative Example 2)
An organic electroluminescent device having a light emitting area portion of 2 mm × 2 mm in size was obtained in the same manner as in Example 2 except that (CBP) shown above was used instead of (E-1). The light emission characteristics of this element are shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² ,
Luminance / current / voltage indicate values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device was 514 nm, which was identified as that from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.30,0.61).

(Comparative Example 3)
An organic electroluminescent device having a light emitting area of 2 mm × 2 mm was obtained in the same manner as in Example 3 except that (CBP) shown above was used instead of (E-2). . The light emission characteristics of this element are shown in Table-1. In Table 1, the maximum light emission luminance is a value at a current density of 0.25 A / cm ² , and the luminance / current / voltage are values at a luminance of 2500 cd / m ² . The maximum wavelength of the emission spectrum of the device was 514 nm, which was identified as that from the organic iridium complex (D-1). The chromaticity was CIE (x, y) = (0.30,0.61).

Example 4
The process up to the formation of the hole injection layer was performed in the same manner as in Example 1. A hole injection layer 3 was formed in the same manner as in Example 1 except that PB-2 was used instead of PB-1 as the non-conjugated polymer and the following conditions were used. (PB-2 (weight average molecular weight: 26500, number average molecular weight: 12000))

Spin coating conditions
Solvent Anisole
Coating solution concentration PB-2 2.0% by weight
A-2 0.4% by weight
Spinner speed 2000rpm
Spinner rotation time 30 seconds Drying conditions 230 ° C. × 5.5 hours A uniform thin film having a thickness of 30 nm was formed by the above spin coating.
Subsequently, the light emitting layer 4 was formed by a wet film forming method as follows. As a material for the light emitting layer 4, an organic compound (E-3) was used together with an iridium complex (D-2) having the structural formula shown below, and spin-coated under the following conditions.

Spin coating conditions
Solvent xylene
Coating concentration E-3 2.5% by weight
D-2 0.13 wt%
Spinner speed 1500rpm
Spinner rotation time 30 seconds Drying conditions 130 ° C x 60 minutes (under reduced pressure)
A uniform thin film having a thickness of 45 nm was formed by the above spin coating.
Next, an aluminum 8-hydroxyquinoline complex (ET-1) was deposited as the electron transport layer 7 in the same manner as in Example 1. The crucible temperature of the aluminum 8-hydroxyquinoline complex at this time is controlled in the range of 321 to 311 ° C., and the degree of vacuum during the deposition is 1.3 to 1.5 × 10 ⁻⁴ Pa (about 1.1 to 1.0 × 10 ⁻⁶ Torr), The deposition rate was 0.08 to 0.16 nm / second and the film thickness was 30 nm.

The substrate temperature during vacuum deposition of the hole blocking layer 8 and the electron transport layer 7 was kept at room temperature.
Here, the element on which the electron transport layer 7 has been deposited is once taken out from the vacuum deposition apparatus into the atmosphere, and a 2 mm wide striped shadow mask is used as the cathode deposition mask.
In close contact with the ITO stripe perpendicular to the ITO stripe, it was placed in a separate vacuum deposition apparatus and the degree of vacuum in the apparatus was 1.8 × 10 ⁻⁶ Torr (about 2.4 × 10 ^{−4) in the same} manner as the organic layer. Pa) exhausted until below. As the electron injection layer 5, lithium fluoride (LiF) is deposited using a molybdenum boat at a deposition rate of 0.01 to 0.06 nm / second, a degree of vacuum of 2.0 × 10 ⁻⁶ Torr (about 2.6 × 10 ⁻⁴ Pa), and 0.5 nm. The film was formed on the electron transport layer 7 with a film thickness of. Next, aluminum was similarly heated by a molybdenum boat, and the deposition rate was 0.1 to 0.3 nm / sec, the degree of vacuum was 3.0 to 6.8 × 10 ⁻⁶ Torr (about 4.0 to 9.0 × 10 ⁻⁴ Pa), and the film thickness was 80 nm. A layer was formed to complete the cathode 6. The substrate temperature at the time of vapor deposition of the above two-layered cathode 6 was kept at room temperature.
As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The maximum wavelength of the emission spectrum of the device was 513 nm, which was identified as that from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.307,0.625). Table 3 shows the light emission characteristics of the device.

(Example 5)
A device was prepared in the same manner except that the organic compound (E-3) of Example 4 was changed to the following organic compound (E-4). The maximum wavelength of the emission spectrum of the device was 512 nm, which was identified as from the iridium complex (D-2). The chromaticity was CIE (x, y) = (0.312,0.618). Table 3 shows the light emission characteristics of the device.

In Table 3, luminance / current and voltage are values at luminance of 100 cd / m ² , and half-life is 100
Each value at 0 cd / A is shown.

In Examples 4 and 5, a light emitting layer was formed by a wet film forming method by selecting a host and a dopant material having similar substituents so as to dissolve each other. Thereby, it is considered that the dopant material is uniformly dispersed in the host material. As a result, uniform light emission was obtained even by a wet film forming method, and an element with high luminous efficiency could be obtained.

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 (8)

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

(In the formula, each aromatic ring may have a substituent. Z represents a direct bond or an arylene group which may have a substituent, and Ar may have a substituent. Represents an aryl group, and two Ars may be the same or different, and Z is linked to a phenyl group bonded to the 2- or 6-position of the pyridine ring. The organic compound according to claim 1, wherein the formula (I) is the following formula (II).

(In the formula, the phenyl groups substituted at the 2-position, 4-position and 6-position of the pyridine ring may have a substituent. Z and Ar have the same meanings as in formula (I).) The organic compound according to claim 2, wherein the formula (II) is the following formula (III).

(In the formula, R _{1 to} R ₄ may have an alkyl group, a cycloalkyl group, an aryl group which may have a substituent, an alkoxy group which may have a substituent, or a substituent. Represents a good aryloxy group, and n represents an integer of 0 to 5.)   A charge transport material comprising the organic compound according to any one of claims 1 to 3.   A charge transport material composition comprising the organic compound according to any one of claims 1 to 3.   The charge transport material composition according to claim 5, further comprising a solvent. An organic electroluminescent device having an anode, a cathode, and a light emitting layer provided between both electrodes on a substrate, comprising a layer containing the organic compound according to any one of claims 1 to 3. An organic electroluminescent element. The organic electroluminescent element of Claim 7 whose layer containing the organic compound of any one of Claim 1 thru | or 3 is a light emitting layer.

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