JP2003272865A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element that is superior in uniformity, high luminous intensity, stability, and low power consumption of light emission. <P>SOLUTION: In the organic electroluminescent element which has an organic layer between a positive electrode and a negative electrode opposed to each other, the organic layer contains an indole derivative trimer (specifically, carboxyl group substituted indole, sulfonic acid group substituted indole, cyano group substituted indole, nitro group substituted indole, amino group substituted indole, halogen group substituted indole or the like are preferable in practical use, and cyano group substituted indole, earboxyl group substituted indole, and sulfonic acid group substituted indole are especially preferable). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an organic electroluminescent device containing an indole derivative trimer in an organic layer.

[0002]

2. Description of the Related Art Inorganic electroluminescent devices using inorganic compounds such as zinc sulfide have advantages such as wider viewing angle and higher contrast than liquid crystal displays (LCD) because they are self-luminous. However, the manufacturing process is complicated, and the driving potential is high.

On the other hand, a light emitting material such as anthracene using an organic compound has been studied for a long time, but it has a low luminance and a low light emitting efficiency in spite of applying a high voltage, and has a low stability.

However, in recent years, in order to improve the above problems,
Electroluminescent devices using organic thin films have been developed. In 1987, in Eastman, USA, an organic electroluminescent device (organic EL device) having a two-layer laminated structure of an organic light emitting layer made of an aluminum complex of 8-hydroxyquinoline and an organic hole transport layer made of an aromatic diamine was developed. (A
ppl. Phys. Lett. , 51, 913, 1
987), E using a conventional single crystal such as anthracene
Although the luminous efficiency has been improved as compared with the L element, there are still problems such as stability (driving life).

In addition to the electroluminescent device using the low molecular weight organic compound as described above, poly (p
-Phenylene Vinylene) (Nature, Volume 347, 5)
39, 1990 et al.), Poly [2-methoxy-5-
(2-Ethylhexyloxy) -1,4-phenylene vinylene] (Appl. Phys. Lett., Volume 58,
1982, etc.), poly (3-alkylthiophene) (J
pn. J. Appl. Phys, Vol. 30, L1938 et al.) And other electroluminescent devices using polymer materials, and devices such as polyvinylcarbazole mixed with low-molecular light emitting materials and electron transfer materials (applied physics, Vol. 61). , 10
(P. 44, 1992), but there are few practical materials such as high brightness, high efficiency, long life, and low cost.

On the other hand, a method of electrolytically oxidatively polymerizing indole-5-carbonitrile and indole-5-carboxylic acid which are indole derivatives in acetonitrile [Ph
ys. Chem. Chem. Phys. , 2,1241
-1248 (2000)] has been reported to form an indole derivative trimer on an electrode, and these compounds have been reported to have fluorescence, and the possibility of application to organic electroluminescence is also described. However, there is no description about a specific element, its configuration, and a manufacturing method.

Further, a symmetric triindole derivative in which all indoles are bonded in the same direction (Japanese Patent Application Laid-Open No. 20-29200)
No. 01-261680) and polymers composed thereof (Japanese Patent Laid-Open No. 2001-288239). The possibility of applying these compounds to organic electroluminescence is also described, but there is no description about a specific device, its structure and manufacturing method. Further, since it is a symmetric type, it has a high flatness, so that it cannot be said that the amorphousness is sufficient, and there are still problems in thinning.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and can be easily formed into a thin film and is excellent in light emitting property and charge transporting property. An object of the present invention is to provide an organic electroluminescent device using an indole derivative trimer, which is excellent in light emission uniformity, stability, high brightness, and low power consumption.

[0009]

As a result of intensive studies to solve these problems, the present inventors have found that an organic layer containing an indole derivative trimer is suitable for this purpose. Reached That is, the present invention is an organic electroluminescent device having an organic layer between an opposing anode and cathode, wherein the organic layer contains an indole derivative trimer. Also,
Higher performance is shown when the indole derivative trimer has a laminated structure.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The organic electroluminescent device of the present invention will be described in detail below.

In the organic electroluminescent device having an organic layer between the facing anode and cathode of the present invention, the indole derivative trimer constituting the organic layer is used as a light emitting material for forming the light emitting layer and also as a hole transporting layer. It can also be used as a charge transporting material such as an electron transporting layer.

As the indole derivative trimer,

[Chemical 5] (In the above formula, R _{1 to} R ₁₅ are hydrogen, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, a linear chain having 2 to 24 carbon atoms. Or a branched acyl group, an aldehyde group, a carboxyl group, a linear or branched carboxylic acid ester group having 2 to 24 carbon atoms,
Sulfonic acid group, C1-C24 linear or branched sulfonic acid ester group, cyano group, hydroxyl group, nitro group, amino group, amide group, dicyanovinyl group, alkyl (C1-C8 linear or branched chain Alkyl group) of oxycarbonylcyanovinyl group, nitrophenylcyanovinyl group and halogen group, each independently selected from the group consisting of substituents. In addition, X ^a- is, chlorine ion, bromine ion,
Iodine ion, Fluorine ion, Nitrate ion, Sulfate ion, Hydrogen sulfate ion, Phosphate ion, Borofluoride ion, Perchlorate ion, Thiocyanate ion, Acetate ion, Propionate ion, Methanesulfonate ion, p
-At least one anion selected from a group of 1 to 3 valent anions consisting of a toluene sulfonate ion, a trifluoroacetate ion, and a trifluoromethane sulfonate ion, and a represents an ionic valence of X, 1 Is an integer of ˜3, m is a doping rate, and its value is 0 to 3.0. ) Is illustrated.

Preferably,

[Chemical 6] (In the above formula, R₁₆~ R_ThirtyIs hydrogen and 1 to 24 carbon atoms
Straight chain or branched alkyl group, straight chain having 1 to 24 carbon atoms
Or a branched alkoxy group, a straight chain having 2 to 24 carbon atoms,
Is a branched acyl group, aldehyde group, carboxyl group, charcoal
Linear or branched carboxylic acid ester having a prime number of 2 to 24
Group, sulfonic acid group, straight or branched chain having 1 to 24 carbon atoms
Sulfonate group, cyano group, hydroxyl group, nitro group,
Amino group, amide group, dicyanovinyl group, alkyl (carbon
Linear or branched alkyl group having a prime number of 1 to 8) Oxical
Bonyl cyanovinyl group, nitrophenyl cyanovinyl group
And independently selected from the group consisting of halogen groups.
R is a substituent₁₆~ R ₂₇At least one of
Whether one is a cyano group, a nitro group, an amido group or a halogen group
It is a group selected from. Also X^a-Is chlorine ion, bromine ion
On, iodine ion, fluoride ion, nitrate ion, sulfuric acid
Ions, hydrogensulfate ions, phosphate ions, fluoroborate
On, perchlorate ion, thiocyanate ion, acetate ion
Ion, propionate ion, methanesulfonate ion, p
-Toluenesulfonate ion, trifluoroacetate ion
And trifluoromethanesulfonate ion
At least one anion selected from a group of 1 to 3 valent anions
Is an ion, a represents the ionic valence of X, and has an integer of 1 to 3
Is a number, m is a doping rate, and the value is 0 to 3.0.
is there. ) Indole derivative trimer represented by

[0014]

[Chemical 7] (In the above formula, R₃₁~ R₄₅Is hydrogen and 1 to 24 carbon atoms
Straight chain or branched alkyl group, straight chain having 1 to 24 carbon atoms
Or a branched alkoxy group, a straight chain having 2 to 24 carbon atoms,
Is a branched acyl group, aldehyde group, carboxyl group, charcoal
Linear or branched carboxylic acid ester having a prime number of 2 to 24
Group, sulfonic acid group, straight or branched chain having 1 to 24 carbon atoms
Sulfonate group, cyano group, hydroxyl group, nitro group,
Amino group, amide group, dicyanovinyl group, alkyl (carbon
Linear or branched alkyl group having a prime number of 1 to 8) Oxical
Bonyl cyanovinyl group, nitrophenyl cyanovinyl group
And independently selected from the group consisting of halogen groups.
R is a substituent₃₁~ R ₄₂At least one of
One is a sulfonic acid group or a carboxyl group. Also X
^a-Is chlorine ion, bromine ion, iodine ion, fluorine
Ion, nitrate ion, sulfate ion, hydrogen sulfate ion,
Nitrate ion, borofluoride ion, perchlorate ion, thio
Cyanate ion, acetate ion, propionate ion,
Tan sulfonate ion, p-toluene sulfonate ion
Ion, trifluoroacetate ion, and trifluoromethane
Selected from a group of 1 to 3 valent anions consisting of sulfonate ions
Is at least one anion extracted, and a is an X ion.
Represents an valence number, is an integer of 1 to 3, and m is a doping rate.
The value is 0 to 3.0. ) Indicated by
And a derivative trimer.

Among these indole derivative trimers,
Carboxyl group-substituted indole trimers, sulfonic acid group-substituted indole trimers, cyano group-substituted indole trimers, nitro group-substituted indole trimers, amide group-substituted indole trimers, halogen group-substituted indoles Practically preferable are trimers and dicyanovinyl group-substituted indole trimers, and trimer having an acidic group such as carboxyl group-substituted indole trimers and sulfonic acid group-substituted indole trimers are water-soluble. Since it is water-soluble, water can be used as a solvent, so that element formation is easy, and it can be used particularly preferably from the viewpoint of safety to human body and environment.

As the indole derivative trimer used in the present invention, an indole derivative trimer obtained by various synthetic methods such as chemical synthesis and electrochemical synthesis can be used.

In the present invention, in particular, the following general formula (4)

[Chemical 8] (In the above formula, R _{46 to} R ₅₀ are hydrogen and carbon atoms 1 to 24.
A straight chain or branched alkyl group, a straight chain or branched alkoxy group having 1 to 24 carbon atoms, a straight chain or branched acyl group having 2 to 24 carbon atoms, an aldehyde group, a carboxyl group, a straight chain group having 2 to 24 carbon atoms. Chain or branched carboxylic acid ester group, sulfonic acid group, linear or branched sulfonic acid ester group having 1 to 24 carbon atoms, cyano group, hydroxyl group, nitro group,
Each independently selected from the group consisting of an amino group, an amide group, a dicyanovinyl group, an alkyl (a linear or branched alkyl group having 1 to 8 carbon atoms) oxycarbonylcyanovinyl group, a nitrophenylcyanovinyl group and a halogen group. It is a substituent. An indole derivative trimer obtained by reacting at least one indole derivative represented by the formula 1) in a reaction mixture containing at least one oxidizing agent and at least one solvent is preferably used.

The indole derivative represented by the general formula (4) used in the method for synthesizing the trimer of the indole derivative is specifically 4-methylindole, 5-methylindole, 6-methylindole, 7- Methylindole, 4-ethylindole, 5-ethylindole, 6
-Ethylindole, 7-ethylindole, 4-n-
Propylindole, 5-n-propylindole, 6
-N-propyl indole, 7-n-propyl indole, 4-iso-propyl indole, 5-iso-propyl indole, 6-iso-propyl indole,
7-iso-propyl indole, 4-n-butyl indole, 5-n-butyl indole, 6-n-butyl indole, 7-n-butyl indole, 4-sec-butyl indole, 5-sec-butyl indole, 6 -
Alkyl group-substituted indoles such as sec-butyl indole, 7-sec-butyl indole, 4-t-butyl indole, 5-t-butyl indole, 6-t-butyl indole, 7-t-butyl indole, 4-methoxy Indole, 5-methoxyindole, 6-methoxyindole, 7-methoxyindole, 4-ethoxyindole, 5-ethoxyindole, 6-ethoxyindole, 7-ethoxyindole, 4-n-propoxyindole, 5-n-propoxyindole , 6-n
-Propoxyindole, 7-n-propoxyindole, 4-iso-propoxyindole, 5-iso-
Propoxyindole, 6-iso-propoxyindole, 7-iso-propoxyindole, 4-n-butoxyindole, 5-n-butoxyindole, 6-
n-butoxyindole, 7-n-butoxyindole, 4-sec-butoxyindole, 5-sec-butoxyindole, 6-sec-butoxyindole,
Alkoxy group-substituted indoles such as 7-sec-butoxyindole, 4-t-butoxyindole, 5-t-butoxyindole, 6-t-butoxyindole, 7-t-butoxyindole, 4-acetylindole, 5-acetyl Acyl group-substituted indoles such as indole, 6-acetylindole, and 7-acetylindole, aldehyde groups such as indole-4-carbaldehyde, indole-5-carbaldehyde, indole-6-carbaldehyde, indole-7-carbaldehyde Carboxyl group-substituted indoles such as substituted indoles, indole-4-carboxylic acid, indole-5-carboxylic acid, indole-6-carboxylic acid, indole-7-carboxylic acid, methyl indole-4-carboxylate, indole-5 -Mo Bonn, methyl indole -
Carboxylic ester group-substituted indoles such as methyl 6-carboxylate and methyl indole-7-carboxylate, indole-4-sulfonic acid, indole-5-sulfonic acid, indole-6-sulfonic acid, indole-7-sulfonic acid Such as sulfonic acid group-substituted indoles, indole-4-methyl sulfonate, indole-5-methyl sulfonate, indole-6-methyl sulfonate, indole-7-methyl sulfonate, etc. Indole-4-carbonitrile, indole-5-carbonitrile, indole-6
-Carbonitrile, indole-7-carbonitrile and other cyano group-substituted indoles, 4-hydroxyindole, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole and other hydroxy group-substituted indoles, 4-nitroindole, Nitro group-substituted indoles such as 5-nitroindole, 6-nitroindole and 7-nitroindole, 4-aminoindole, 5-aminoindole, 6-aminoindole, 7-aminoindole and other amino group-substituted indoles, 4 -Carbamoylindole, 5-carbamoylindole, 6-carbamoylindole, 7-carbamoylindole and other amido-substituted indoles, 4
-Fluoroindole, 5-Fluoroindole, 6-
Fluoroindole, 7-fluoroindole, 4-chloroindole, 5-chloroindole, 6-chloroindole, 7-chloroindole, 4-bromoindole, 5-bromoindole, 6-bromoindole, 7
-Halogen group-substituted indoles such as -bromoindole, 4-iodoindole, 5-iodoindole, 6-iodoindole, 7-iodoindole, 4-dicyanovinylindole, 5-dicyanovinylindole,
Dicyanovinyl group-substituted indoles such as 6-dicyanovinylindole and 7-dicyanovinylindole, N
-Methylindole, N-ethylindole, Nn-
Examples thereof include N-alkyl group-substituted indoles such as propylindole, N-iso-propylindole, Nn-butylindole, N-sec-butylindole, and Nt-butylindole.

Among these, carboxyl group-substituted indoles, sulfonic acid group-substituted indoles, cyano group-substituted indoles, nitro group-substituted indoles, amide group-substituted indoles, halogen group-substituted indoles and the like are practically preferable, and cyano group is preferable. Substituted indoles, carboxyl group-substituted indoles, and sulfonic acid group-substituted indoles are particularly preferable.

The oxidizing agent used in the method for synthesizing the trimer of the indole derivative is not particularly limited, and examples thereof include ferric chloride hexahydrate, anhydrous ferric chloride, ferric nitrate nonahydrate, and sulfuric acid. Ferric n-hydrate, ferric ammonium sulfate dodecahydrate, ferric perchlorate n-hydrate, ferric tetrafluoroborate, cupric chloride, cupric nitrate, ferric sulfate Examples thereof include copper, cupric tetrafluoroborate, nitrosonium tetrafluoroborate, hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate and potassium periodate. Among them, ferric chloride hexahydrate, anhydrous ferric chloride, cupric chloride, cupric tetrafluoroborate,
Ammonium persulfate is practically preferable, and among them, ferric chloride hexahydrate and anhydrous ferric chloride are most preferable practically. In addition, even if these oxidizing agents are used alone,
Also, two or more kinds may be used in combination at any ratio.

The indole derivative used in the above-mentioned method for synthesizing the trimer of indole derivative and the oxidizing agent are used at a molar ratio of indole derivative: oxidizing agent = 1: 0.5 to 100, preferably 1: 1 to 50. To be Here, if the proportion of the oxidant is low, the reactivity is lowered and the raw material remains. On the contrary, if the proportion is too high, the produced trimer may be peroxidized to cause deterioration of the product.

As the solvent used in the method for synthesizing the indole derivative trimer, water or an organic solvent can be used. The organic solvent is not particularly limited, but methanol, ethanol, isopropanol, acetone, acetonitrile, propionitrile, tetrahydrofuran, 1,4-dioxane, methyl isobutyl ketone, methyl ethyl ketone, γ-butyl lactone, propylene carbonate, sulfolane, nitromethane, N, N-dimethylformamide, N-methylacetamide, dimethyl sulfoxide, dimethyl sulfone, N-methylpyrrolidone, benzene, toluene, xylene, methylene chloride, chloroform, dichloroethane and the like are used. These solvents may be used alone, or two or more kinds may be mixed and used at an arbitrary ratio. Among these solvents, acetone, acetonitrile, 1,4-dioxane, γ-butyl lactone, N,
N-dimethylformamide and the like are preferable, and acetonitrile is most preferable for practical use.

Further, in the method for synthesizing the indole derivative trimer described above, it is particularly preferable to react with water and an organic solvent coexisting. The molar ratio of the indole derivative to water used is indole derivative: water = 1: 1000 to 100.
It is used 0: 1, preferably 1: 100 to 100: 1. However, if the oxidizing agent has water of crystallization, the amount of water of crystallization is also measured as water. Here, if the proportion of water is low, the reaction may run away, and the trimer may be peroxidized to cause structural deterioration, and at the same time, ^{Xa- serving as a} dopant may not be efficiently doped into the trimer, and the conductivity may decrease. May decrease. On the other hand, if the proportion is too high, the progress of the oxidation reaction may be hindered and the reaction yield may decrease.

In the method for synthesizing the indole derivative trimer, the concentration of the indole derivative during the reaction is 0.01% by mass or more, preferably 0.1 to 50% by mass, relative to the solvent.
More preferably, it is in the range of 1 to 30 mass%.

General formulas (1) to (3) used in the present invention
In the X ^a- indole derivative trimer represented a dopant, an anion of a protic acid derived from the oxidation agent in the polymerization. Specifically, chlorine ion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion, hydrogen sulfate ion, phosphate ion, borofluoride ion, perchlorate ion, thiocyanate ion, acetate ion, propionic acid. 1 to 3 valent anions such as ion, p-toluenesulfonate ion, trifluoroacetate ion, trifluoromethanesulfonate ion and the like, preferably 1 ion such as chloride ion, sulfate ion and borofluoride ion.
~ A divalent anion. Most preferred are monovalent anions such as chloride. For example, when anhydrous ferric chloride is selected as the oxidant for polymerization, the dopant ^Xa- in the indole derivative trimer becomes chlorine ion,
When the polymerization was carried out using cupric trifluoroacetate,
The dopant ^Xa- becomes trifluoroacetate ion.

The indole derivative trimer obtained by the above-mentioned method for synthesizing the indole derivative trimer is a doped type indole derivative trimer except when hydrogen peroxide or ozone is used as an oxidizing agent, and the dopant X ^{a -} the molar ratio of (doping ratio) m is from 0.001 to 3.0. When hydrogen peroxide or ozone is used as the oxidant, m = 0. From the viewpoint of the conductivity of the organic electroluminescent device, the doping rate m is preferably 0.001 to 3.0.

The N-alkyl group-substituted indole derivative acid monomer may be trimerized by using the N-alkyl group-substituted indole derivative as a raw material, or a known alkylating agent may be prepared by synthesizing the trimer. It can also be used for synthesis.

The indole derivative trimer may be dedoped for the purpose of further improving the solubility in a solvent for forming an organic layer by coating and for preventing the suppression of charge transfer. The dedoping treatment method is not particularly limited, but, for example, a conventionally known method is used as a dedoping step for various conductive polymers and charge transfer complexes. That is, a method of suspending an indole derivative trimer in an alkaline solution such as aqueous ammonia, sodium hydroxide, potassium hydroxide or lithium hydroxide to remove the dopant ^Xa- , or a dedoping type indole derivative by a reduction treatment. A method of obtaining a trimer (that is, a doping ratio m = 0) can be mentioned.

The dedoped indole derivative trimer is
It is possible to easily convert an arbitrary dopant into an indole derivative trimer having a desired doping ratio by treatment with an arbitrary type and an arbitrary amount of a doping agent again. For example, a doped indole derivative trimer polymerized with an oxidizing agent having a counter ion other than chloride ion is dedoped with a sodium hydroxide solution to give a dedoped indole derivative trimer, which is then treated with an aqueous hydrochloric acid solution. It is also possible to induce a chlorine-doped indole derivative trimer by re-suspending it in the solution. The indole derivative trimer doped with any dopant thus obtained can be used in the organic layer of the organic electroluminescent device of the present invention.

Since the indole derivative trimer has a laminated structure, it may have more excellent properties such as light emitting property and charge transporting property as an organic electroluminescent device. In particular, it is preferable to have a laminated structure with a layer interval of 0.1 to 0.6 nm. The compound having such an ultrafine laminated structure has excellent physical properties such as rigidity, strength and heat resistance. However, when the layer spacing is 0.1 nm or more, the laminated structure tends to be more stable, and when the layer spacing is 0.6 nm or less, electron hopping conduction between trimers is facilitated, and light emission characteristics and charge transport ability are improved. Tends to improve.

When these indole derivative trimers are used as an organic electroluminescent device, their purities affect charge transport properties and luminescent properties, and therefore, purification methods such as recrystallization, reprecipitation purification, and sublimation purification after synthesis. It is preferable to use to make the product highly purified.

In the present invention, the organic material layer containing the indole derivative trimer is (I) a layer consisting only of the indole derivative trimer, (II) the indole derivative trimer and another hole transport layer or electron transport layer. A layer in which a charge-transporting material such as a layer is mixed, a layer in which the (III) indole derivative trimer and another light-emitting material are mixed, (IV) an indole derivative trimer and another charge-transporting material, and another A layer in which a light emitting material is mixed, (V) or a layer in which any one of these four is further mixed with at least one kind of polymer compound,
Either of them may be used. Where other charge transport materials,
The use of the light emitting material is for improving the charge transporting property and the light emitting property, respectively, and the mixing of the polymer compound is effective for improving the film forming property and the film strength.

The organic layer containing the indole derivative trimer may be used alone, or may be a charge transporting layer such as a hole transporting layer or an electron transporting layer, a light emitting layer, or the like. You may laminate with both. Further, an organic layer having other characteristics such as a buffer layer can be laminated and used.

The light emitting material used for mixing with the trimer of the indole derivative or for being laminated as another light emitting layer is not particularly limited as long as it shows fluorescence in the solid state. Specific examples of the low molecular weight compound include naphthalene derivative, anthracene and its derivative, pyrene derivative, perylene and its derivative, polymethine type, xanthene type, coumarin type and cyanine type dyes, 8
-Aluminum and other metal complexes of hydroxyquinoline and its derivatives, aromatic amines, tetraphenylcyclopentadiene and its derivatives, tetraphenylbutadiene and its derivatives and the like. Further, as the polymer compound, poly (p-phenylene vinylene) is used.
(Nature, 347, 539, 1990), poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene], poly (3-
Alkylthiophene) and the like.

Specific materials include aromatic compounds such as tetraphenyl butadiene (JP-A-57-51781) and metal complexes such as aluminum complexes of 8-hydroxyquinoline (JP-A-59-194393). Metal complexes of 10-hydroxybenzo [h] quinoline (JP-A-6-322362), mixed-ligand aluminum chelate complexes (JP-A-5-198377, JP-A-5-198378, JP-A-5-198378).
-214332, Japanese Unexamined Patent Publication No. 6-172751, Cyclopentadiene derivative (Japanese Unexamined Patent Publication No. 2-289675), Perinone derivative (Japanese Unexamined Patent Publication No. 2-289676), Oxadiazole derivative (Japanese Unexamined Patent Publication No. 2-216791) , Bistyrylbenzene derivatives (JP-A 1-245087, JP-A 2-222484)
JP), perylene derivatives (JP-A-2-189890,
JP-A-3-791), coumarin compounds (JP-A2-1)
91694, JP-A-3-792), rare earth complex (JP-A-1-256584), distyrylpyrazine derivative (JP-A-2-252793), p-phenylene compound (JP-A-3-33183). Gazette), thiadiazolopyridine derivative (JP-A-3-37292), pyrrolopyridine derivative (JP-A-3-37293), naphthyridine derivative (JP-A-3-203982), silole derivative (Chemical Society of Japan No. 1) 70 Spring Annual Meeting, 2D1 02 and 2D1 03, 1996). These compounds may be used alone, or may be mixed and used as needed.

The hole transport material used for mixing with the indole derivative trimer or being laminated as another hole transport layer is not particularly limited. As such a hole transport material, 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-A-59-59). 194393), 4,2'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl containing two or more tertiary amines and two or more condensed aromatic rings containing nitrogen atoms. Substituted aromatic amine (JP-A-5-234681), aromatic triamine having a starburst structure with a derivative of triphenylbenzene (US Pat. No. 4,923,774), N, N'-diphenyl-N , N′-bis (3-methylphenyl) biphenyl-4,4′-diamine and other aromatic diamines (US Pat. No. 4,764,625), α, α, α ′, α′-
Tetramethyl-α, α'-bis (4-di-p-tolylaminophenyl) -p-xylene (JP-A-3-26908)
4), a sterically asymmetric triphenylamine derivative as a whole molecule (JP-A-4-12927),
A compound in which a pyrenyl group is substituted with a plurality of aromatic diamino groups (JP-A-4-175395), an aromatic diamine in which a tertiary aromatic amine unit is linked by an ethylene group (JP-A-4-264189), and a styryl structure Having an aromatic diamine (JP-A-4-290851), an aromatic tertiary amine unit linked by a thiophene group (JP-A-4-304466), a starburst type aromatic triamine (JP-A-4-308688). Issue),
Benzylphenyl compounds (JP-A-4-364153), compounds in which tertiary amines are linked by fluorene groups (JP-A-5-25473), triamine compounds (JP-A-5-239455), bisdipyridylaminobiphenyl ( JP-A-5-320634), N, N, N
-Triphenylamine derivative (JP-A-6-1972), aromatic diamine having phenoxazine structure (Japanese Patent Application No. 5-290728), diaminophenylphenanthridine derivative (Japanese Patent Application No. 6-45669), hydrazone Compound (JP-A-2-311591), silazane compound (US Pat. No. 4,950,950), silanamin derivative (JP-A-6-49079), phosphamine derivative (JP-A-6-25659), Quinacridone compound, polyvinylcarbazole and polysilane (Appl. Phys. Lett., Vol. 59, 2760)
Page, 1991), Polyphosphazene (Japanese Patent Laid-Open No. 5-3
10949), polyamide (JP-A-5-3109).
49), polyvinyltriphenylamine (Japanese Patent Application No. 5-205377), a polymer having a triphenylamine skeleton (Japanese Patent Laid-Open No. 1333065), and a polymer in which triphenylamine units are linked by a methylene group or the like ( Syn
thetic Metals, 55-57, 4163.
P., 1993), polymethacrylates containing aromatic amines (J. Polym. Sci., Polym. C.
hem. Ed. , 21: 969, 1983) and the like. These compounds may be used alone, or may be used as a mixture if necessary.

The electron transporting material used for mixing with the indole derivative trimer or being laminated as another electron transporting layer is not particularly limited. As such an electron transporting material, aromatic compounds such as tetraphenyl butadiene (JP-A-57-51781), 8
-A metal complex such as aluminum complex of hydroxyquinoline (JP-A-59-194393), cyclopentadiene derivative (JP-A-2-289675), perinone derivative (JP-A-2-289676), oxadiazole derivative (JP-A-2-216791),
Bisstyrylbenzene derivative (Japanese Patent Laid-Open No. 1-245087)
JP-A-2-222484), perylene derivatives (JP-A-2-189890 and JP-A-3-791), coumarin compounds (JP-A-2-191964 and JP-A-3-792), rare earths. Complex (JP-A 1-2
56584), a distyrylpyrazine derivative (JP-A-2-
No. 252793), p-phenylene compounds (JP-A-3-33183), thiadiazolopyridine derivatives (JP-A-3-37292), pyrrolopyridine derivatives (JP-A-3-37293), naphthyridine derivatives (JP-A-3-37293). JP-A-3-203982) and the like. These compounds may be used alone, or may be used as a mixture if necessary.

Further, an indole derivative trimer, a mixture of the indole derivative trimer and the light emitting material, a mixture of the indole derivative trimer and the hole transport material, or an indole derivative trimer and the electron transport material. The polymer compound used with the mixture with is not particularly limited, but those that do not extremely disturb the charge transport property and the light emitting property are preferable, and for example, poly (N-vinylcarbazole),
Polyaniline and its derivatives, polythiophene and its derivatives, poly (p-phenylene vinylene) and its derivatives, poly (2,5-thienylene vinylene) and its derivatives, polyvinyl alcohols such as polyvinyl alcohol, polyvinyl formal and polyvinyl butyral, poly Acrylic amides, poly (Nt-butyl acrylic amide), polyacrylic amides such as polyacrylic amide methylpropane sulfonic acid, polyvinylpyrrolidones, alkyd resins, melamine resins, urea resins, phenolic resins, epoxy resins, polybutadiene resins, Acrylic resin, urethane resin, vinyl ester resin, urea resin, polyimide resin, maleic acid resin, polycarbonate resin, vinyl acetate resin, chlorinated polyethylene resin, chlorinated resin Propylene resins, acryl / styrene copolymer resin, a vinyl acetate / acrylic copolymer resin, polyester resin, styrene / maleic acid copolymer resin, fluorine resin and copolymers and the like. Further, these polymer compounds may be a mixture of two or more kinds at an arbitrary ratio.

Here, poly (N-vinylcarbazole), polyaniline and its derivatives, polythiophene and its derivatives, poly (p-phenylenevinylene) and its derivatives, poly (2,5-thienylenevinylene).
And the derivative thereof also have the action as the above-mentioned charge transporting compound.

The ratio of the polymer compound to be used is not particularly limited, but is 0 with respect to 100 parts by mass of the above indole derivative trimer or a mixture of the indole derivative trimer and the charge transport material. .01 to 10,000
0 parts by mass, preferably 1 to 100,000 parts by mass is used.

The organic layer containing the indole derivative trimer is formed by a vacuum vapor deposition method or a method of forming a composition containing the indole derivative trimer and a solvent.
When forming from a solution, spin coating method, casting method, bar coating method, roll coating method, gravure coating method, curtain flow coating method, reverse coating method, kiss coating method, fan ten coating method, rod coating method, air doctor coating A known method such as a coating method such as a coating method, a knife coating method, a blade coating method, a screen coating method, a spray coating method, a spraying method such as an inkjet method, or a dipping method such as dipping can be used. When mixed with other light-emitting material, charge transport material or polymer compound, they may be mixed in advance to form a film by the above method, and in the case of vacuum vapor deposition method, co-evaporation from different vapor deposition sources. You may. In addition, when a thin film is formed by a coating method, in order to remove the solvent, the temperature is from room temperature to 250 ° C., and further 40
It is preferable to perform heat treatment at a temperature of 150 ° C. Also,
The heat treatment is preferably performed under reduced pressure or in an inert atmosphere.

The solvent of the composition used when forming an organic layer containing the indole derivative trimer of the present invention by a coating method is a mixture of an indole derivative trimer, an indole derivative trimer and a luminescent material, There is no particular limitation as long as it is a mixture or mixture of an indole derivative trimer and a charge transporting material or a mixture of these and a polymer compound, which is dissolved or dispersed, and water or an organic solvent is used. As the organic solvent, alcohols such as methanol, ethanol, propanol and isopropanol, acetone,
Ketones such as methyl isobutyl ketone, ethers such as isopropyl ether and methyl-t-butyl ether, cellosolves such as methyl cellosolve and ethyl cellosolve, propylene glycols such as methyl propylene glycol and ethyl propylene glycol, dimethylformamide, dimethylacetamide. And the like, pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone, and dimethylsulfoxide are preferably used. In particular, water, methanol, isopropanol, acetone, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are more preferable in terms of solubility in the indole derivative trimer. In addition, these solvents may be used alone or in a mixture at an arbitrary ratio.

The use ratio of the indole derivative trimer, the mixture of the indole derivative trimer and the light emitting material, the mixture of the indole derivative trimer and the charge transport material, or the mixture of the polymer compound and the indole derivative trimer is as follows. 1
It is 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass with respect to 00 parts by mass. When the proportion of the trimer of the indole derivative is 20 parts by mass or more, the solubility is low and the smoothness of the film is low.

When the indole derivative trimer is applied from a solution, the basic compound is added to the composition to dedope the indole derivative trimer and dissolve the indole derivative trimer in a solvent. It has the effect of further improving the sex. In the case of carboxyl group-substituted indole trimers and sulfonic acid group-substituted indole trimers, the solubility in water is particularly improved by forming a salt with a sulfonic acid group and a carboxyl group. The basic compound is not particularly limited, but for example, ammonia, aliphatic amines, cyclic saturated amines, cyclic unsaturated amines, ammonium salts, inorganic bases and the like are preferably used.

The structural formulas of amines used as basic compounds are shown below.

[Chemical 9] In the formula, R _{51 to} R ₅₃ each independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms (C _{1 to} C ₄ ), CH ₂ OH, and CH.
_{2 represents} CH ₂ OH, CONH ₂ or NH ₂ .

The structural formula of the ammonium salt used as the basic compound of the present invention is shown below.

[Chemical 10] In the formula, R _{54 to} R ₅₇ are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms (C _{1 to} C ₄ ), CH ₂ OH, and CH.
₂ CH ₂ OH, CONH ₂ or NH ₂ ; X ⁻ is OH ⁻ , 1/2 · SO ₄ ²⁻ , NO ₃ ⁻ , 1 / 2CO ₃
^2- , HCO ₃ ⁻ , 1/2 · (COO) ₂ ²⁻ , or R′COO ⁻ [In the formula, R ′ has ₁ to 3 carbon atoms (C ₁ to
It represents a a a] alkyl C _3).

Examples of the cyclic saturated amines include piperidine,
Pyrrolidine, morpholine, piperazine, derivatives having these skeletons, and ammonium hydroxide compounds thereof are preferably used.

Examples of the cyclic unsaturated amines include pyridine,
α-picoline, β-picoline, γ-picoline, quinoline, isoquinoline, pyrroline, derivatives having these skeletons, and ammonium hydroxide compounds thereof are preferably used.

As the inorganic base, hydroxide salts such as sodium hydroxide, potassium hydroxide and lithium hydroxide are preferably used.

Basic compounds may be used by mixing two or more kinds.
Is also good. For example, mixing amines and ammonium salts
Can be used to further improve the conductivity.
It Specifically, NH_Three/ (NH_Four)_TwoCO_Three, NH_Three
/ (NH_Four) HCO_Three, NH _Three/ CH_ThreeCOONH_Four,
NH_Three/ (NH_Four)_TwoSO_4,N (CH_Three)_Three/ CH _Three
COONH_Four, N (CH_Three)_Three/ (NH_Four)_TwoSO_FourNa
Which can be mentioned. Also, use these mixing ratios at any ratio.
Can be used, but amines / ammonium salts = 1
/ 10 to 10/0 is preferable.

The proportion of the basic compound used is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the solvent. When the proportion of the basic compound is 10 parts by mass or less, the solubility and the emission property are both excellent, which is preferable.

The composition of the present invention may contain, if necessary, a crosslinking agent such as a silane coupling agent, colloidal silica, a surfactant, a storage stabilizer, an adhesion aid, a dye or a pigment.

The film of the organic layer containing the indole derivative trimer of the present invention has a film thickness of 1 nm to 10000 nm, preferably 5 nm to 1000 nm, more preferably 10 nm to 5 nm.
Film can be formed to 00 nm

As the support of the organic electroluminescence device of the present invention, a plate of quartz or glass, a metal plate or a metal foil, a plastic film or a sheet, or the like is used. In particular, a glass plate and a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. When using a synthetic resin substrate, it is necessary to pay attention to the gas barrier property. If the gas barrier property of the substrate is too small, the organic electroluminescent element may deteriorate due to the outside air passing through the substrate, which is not preferable. Therefore, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on the synthetic resin substrate is also a preferable method.

The electrodes in the organic electroluminescent device of the present invention will be described below. The anode is formed on the support, and holes are injected into the organic light emitting layer. As the anode, a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a halogenated metal such as copper iodide,
It is composed of carbon black or a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline. The anode is often formed by a sputtering method, a vacuum deposition method, or the like. Also,
In the case of fine particles of metal such as silver, fine particles of copper iodide, carbon black, fine particles of conductive metal oxide, fine powder of conductive polymer, etc., disperse in a suitable binder resin solution and apply on a substrate. Thus, the anode can be formed. Further, in the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or a conductive polymer can be applied on the substrate to form an anode. The anode can be formed by stacking different materials. The thickness of the anode depends 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 is usually 5 to 1000 nm, preferably 10 to 5
It is about 00 nm. The anode may be the same as the substrate if it may be opaque. Further, it is also possible to stack different conductive materials on the anode.

The cathode is used to inject electrons into the organic light emitting layer. The material used as the cathode, it is possible to use the material used for the anode, in order to perform electron injection efficiently, a low work function metal is preferable, tin, magnesium, indium, calcium, aluminum, A suitable metal such as silver or an alloy thereof is used. The thickness of the cathode is usually the same as that of the anode. On top of this for the purpose of protecting the cathode made of low work function metal,
Laminating a metal layer having a high work function and stable to the atmosphere increases the stability of the device. Metals such as aluminum, silver, nickel, chromium, gold and platinum are used for this purpose. As a transparent or semitransparent electrode of the pair of electrodes, a transparent or semitransparent electrode is formed on a transparent substrate such as glass or transparent plastic. This is the anode. A conductive metal oxide film, a semitransparent metal thin film, or the like is used as a material for the electrodes. Specifically, indium tin oxide film (ITO film), tin oxide film (NESA film),
A thin film of Au, Pt, Ag, Cu or the like is used. As a manufacturing method, a vacuum vapor deposition method, a sputtering method, a plating method or the like is used.

The structure of the organic electroluminescent element of the present invention will be described below. The structure of the element can be a known structure. For example, anode / light emitting layer / cathode (/ indicates that layers are stacked), anode / hole transport layer / light emitting layer / cathode, anode / (mixture layer of charge transport material and light emitting material) / cathode, or A structure of anode / hole transport layer / (mixture layer of charge transport material and light emitting material) / cathode can be adopted. Also,
A combination structure having an electroconductive polymer layer between the anode and the hole transport layer can be adopted, and a combination structure having an electron transport layer between the light emitting layer and the cathode can also be adopted. Further, the structure of anode / conductive polymer layer / hole transport layer / light emitting layer / electron transport layer / cathode can be adopted.

[0058]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

In the synthesis example of the indole derivative trimer, elemental analysis was carried out by EA11 manufactured by Thermoquest Co.
It was measured at 10. The electrical conductivity was measured with a Mitsubishi Chemical Lorester meter MCP-T350 (4 terminal method: distance between electrodes 1 mm). Furthermore, X-ray diffraction analysis (XRD) was performed by Rigaku Denki Co., Ltd. RINT-1100 (tube: CuK _α X
Line).

Synthesis Example 1 Synthesis of Indole-5-carboxylic acid trimer 10 ml of acetonitrile in a 200 ml three-necked flask.
Was added and 1.42 g of indole-5-carboxylic acid was dissolved. On the other hand, the preparation of the oxidant solution is 40 m of acetonitrile
16.2 g of anhydrous ferric chloride and 5.4 g of water were dissolved in 1 and stirred for 10 minutes. Next, after the prepared oxidizing agent solution was added dropwise to the indole-5-carboxylic acid aqueous solution over 30 minutes, the mixture was stirred at 60 ° C. for 10 hours. The reaction solution changed from pale yellow to pale green with some heat generation, and its pH was 1 or less. After completion of the reaction, the mixture was suction filtered with a Kiriyama funnel, washed with acetonitrile and then with methanol, and dried to give pale green 6,11-dihydro-5H-diindolo [2,3-a: 2 ′, 3′-c] carbazole. -2
1.12 g (yield 79%) of 9,14-tricarboxylic acid and (indole-5-carboxylic acid trimer) were obtained. The obtained trimer is pressure-molded with a tablet molding machine to obtain a diameter of 10 mm,
When it was cut into a shape having a thickness of 1 mm and the conductivity was measured by the four-terminal method, it was 0.41 S / cm. The results of elemental analysis _{(C 9 .00 H 4.90 N 1.09} O 1.98 C
l _0.11 ) ₃ . As a result of X-ray diffraction crystal analysis, the layer spacing was 0.48 nm.

Synthesis Example 2 Synthesis of indole-5-carbonitrile trimer Polymerization was carried out in the same manner as in Synthesis Example 1 except that indole-5-carbonitrile was used instead of indole-5-carboxylic acid in Synthesis Example 1. I went. Green 6,11-
Dihydro-5H-diindolo [2,3-a: 2 ', 3'
-C] carbazole-2,9,14-tricarbonitrile, (indole-5-carbonitrile trimer) 1.2
2 g (yield 86%) was obtained. The obtained trimer was pressure-molded with a tablet molding machine, cut into a shape having a diameter of 10 mm and a thickness of 1 mm, and the conductivity was measured by the four-terminal method.
It was 50 S / cm. The result of elemental analysis is (C _9.00
H _{4 . 03} N _1.97 Cl _0.10 ) ₃ . As a result of X-ray diffraction crystal analysis, the layer spacing was 0.44 nm.

Synthesis Example 3 Undoped indole-5-carbonitrile trimer
Synthesis of Indole-5-carbonitrile synthesized in Synthesis Example 7
Disperse 1.00 g of trimer in 1M ammonia water,
Stir for 1 hour. After stirring, suction filtration with a Kiriyama funnel, water,
Then wash with methanol, dry, and black dedope
State indole-5-carbonitrile trimer 0.95
g was obtained. Press molding of the obtained trimer with a tablet molding machine
With a diameter of 10mm and a thickness of 1mm
Conductivity measured by the method is 0.04 S / cm or less
Met. The result of elemental analysis is (C _9.00H_4.02N
_2.02)_ThreeMet.

Composition 1 6,11-Dihydro-5H-diindolo of Synthesis Example 1 above
[2,3-a: 2 ', 3'-c] carbazole-2,9,
A composition was prepared by dissolving 0.5 parts by mass of 14-tricarboxylic acid and (trimer of indole-5-carboxylic acid) in 100 parts by mass of dimethylformamide with stirring at room temperature.

Composition 2 5 parts by mass of indole-5-carboxylic acid trimer and 1 part by mass of ammonia were dissolved in 100 parts by mass of water with stirring at room temperature to prepare a composition.

Composition 3 1 part by weight of indole-5-carbonitrile trimer, N-
A composition was prepared by stirring and dissolving in 100 parts by mass of methylpyrrolidone at room temperature.

Composition 4 A composition was prepared by dissolving 3 parts by mass of the undoped indole-5-carbonitrile trimer and 100 parts by mass of N-methylpyrrolidone at room temperature with stirring.

<Production and Evaluation of Device> Example 1 4,4′-bis (3-methyl-diphenylamino) biphenyl (hereinafter sometimes referred to as TPD) is formed on a glass substrate having an ITO film with a thickness of 400 nm formed by sputtering. .) Was deposited by vapor deposition to a thickness of 50 nm. Then, the composition 1 was spin-coated (500 rpm × 5 sec).
+2000 rpm × 60 sec), dried at 150 ° C. for 10 minutes, and formed a film with a thickness of 50 nm. Furthermore, 2- (4
-Biphenylyl) -5- (4-t-butylphenyl)-
1,3,4-Oxadiazole was evaporated to a thickness of 50 nm. In addition, vapor deposition of organic substances is 0.1 to 0.2 nm / s.
At the speed of. Finally, a magnesium-silver alloy (Mg: Ag = 9: 1 mass ratio) as a cathode was formed on top of it by 150.
An organic electroluminescent device was produced by vapor deposition with a thickness of nm. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less. When a voltage of 13.0V was applied to this element,
A current of about 100 mA / cm ² flowed, and uniform EL emission was observed. The peak of the emission spectrum was 440 nm, and the emission color was blue.

Example 2 Composition 2 was spin-coated (500 r) on a glass substrate having an ITO film with a thickness of 400 nm formed by sputtering.
pm × 5sec + 2000rpm × 60sec), 1
It was dried at 50 ° C. for 10 minutes and formed into a film with a thickness of 50 nm.
Furthermore, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole was added to 50n.
It was vapor-deposited in a thickness of m. In addition, the vapor deposition of organic substances is 0.1
It was performed at a speed of 0.2 nm / s. Finally, a magnesium-silver alloy (Mg: Ag = 9: 1 mass ratio) as a cathode was vapor-deposited thereon with a thickness of 150 nm to produce an organic electroluminescence device. The degree of vacuum during vapor deposition is 8 × 10 ^-6 T
It was below orr. When a voltage of 13.0 V was applied to this device, a current of about 110 mA / cm ² flowed, and uniform EL emission was observed. The peak of the emission spectrum was 440 nm, and the emission color was blue.

Example 3 4,4′-bis (3-methyl-diphenylamino) biphenyl (hereinafter sometimes referred to as TPD) was vapor-deposited to a thickness of 50 nm on a glass substrate having an ITO film with a thickness of 400 nm formed by sputtering. The film was formed to a thickness. Then, the composition 3 was spin-coated (500 rpm × 5 sec).
+2000 rpm × 60 sec), dried at 150 ° C. for 10 minutes, and formed a film with a thickness of 50 nm. Finally, a magnesium-silver alloy (Mg: Ag = 9:
1 mass ratio) was vapor-deposited with a thickness of 150 nm to produce an organic electroluminescence device. The degree of vacuum during vapor deposition is 8 x 10
It was ^-6 Torr or less. When a voltage of 13.0 V was applied to this element, a current of about 95 mA / cm ² flowed,
Uniform EL emission was observed. The peak of the emission spectrum was 440 nm, and the emission color was blue.

Example 4 4,4′-bis (3-methyl-diphenylamino) biphenyl (hereinafter sometimes referred to as TPD) was vapor-deposited to a thickness of 50 nm on a glass substrate having an ITO film with a thickness of 400 nm formed by sputtering. The film was formed to a thickness. Then, the composition 4 was spin-coated (500 rpm × 5 sec).
+2000 rpm × 60 sec), dried at 150 ° C. for 10 minutes, and formed a film with a thickness of 50 nm. Furthermore, 2- (4
-Biphenylyl) -5- (4-t-butylphenyl)-
1,3,4-Oxadiazole was evaporated to a thickness of 50 nm. In addition, vapor deposition of organic substances is 0.1 to 0.2 nm / s.
At the speed of. Finally, a magnesium-silver alloy (Mg: Ag = 9: 1 mass ratio) as a cathode was formed on top of it by 150.
An organic electroluminescent device was produced by vapor deposition with a thickness of nm. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less. When a voltage of 13.0V was applied to this element,
A current of about 90 mA / cm ² flowed, and uniform EL emission was observed. The peak of the emission spectrum was 440 nm, and the emission color was blue.

[0071]

Industrial Applicability The organic electroluminescent device using the light emitting material of the present invention has excellent uniformity of light emission, high brightness, stability and low power consumption, and is a surface light source as a backlight. It can be used as a display material for a flat panel display and the like.

Claims (9)

[Claims] 1. An organic electroluminescent device having an organic layer between an opposing anode and cathode, wherein the organic layer contains an indole derivative trimer. 2. An indole derivative trimer is represented by: (In the above formula, R _{1 to} R ₁₅ are hydrogen, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, a linear chain having 2 to 24 carbon atoms. Or a branched acyl group, an aldehyde group, a carboxylic acid group, a linear or branched carboxylic acid ester group having 2 to 24 carbon atoms, a sulfonic acid group, a linear or branched sulfonic acid ester group having 1 to 24 carbon atoms, cyano Group, hydroxyl group, nitro group, amino group, amide group, dicyanovinyl group, alkyl (carbon number 1
.About.8 linear or branched alkyl group) each independently selected from the group consisting of an oxycarbonylcyanovinyl group, a nitrophenylcyanovinyl group and a halogen group. Further, X ^a- is chlorine ion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion, hydrogen sulfate ion, phosphate ion, fluoroborate ion, perchlorate ion, thiocyanate ion, acetate ion, Propionate ion, methanesulfonate ion, p-toluenesulfonate ion, trifluoroacetate ion, and at least one anion selected from a group of 1 to 3 valent anions consisting of trifluoromethanesulfonate ion, a represents the ionic valence of X, is an integer of 1-3,
m is a doping rate, and its value is 0 to 3.0. ) Is an organic electroluminescent device according to claim 1. 3. The indole derivative trimer comprises: [Chemical 2] (In the above formula, R₁₆~ R_ThirtyIs hydrogen and 1 to 24 carbon atoms
Straight chain or branched alkyl group, straight chain having 1 to 24 carbon atoms
Or a branched alkoxy group, a straight chain having 2 to 24 carbon atoms,
Is a branched acyl group, aldehyde group, carboxyl group, charcoal
Linear or branched carboxylic acid ester having a prime number of 2 to 24
Group, sulfonic acid group, straight or branched chain having 1 to 24 carbon atoms
Sulfonate group, cyano group, hydroxyl group, nitro group,
Amino group, amide group, dicyanovinyl group, alkyl (carbon
Linear or branched alkyl group having a prime number of 1 to 8) Oxical
Bonyl cyanovinyl group, nitrophenyl cyanovinyl group
And independently selected from the group consisting of halogen groups.
R is a substituent₁₆~ R ₂₇At least one of
Whether one is a cyano group, a nitro group, an amido group or a halogen group
It is a group selected from. Also X^a-Is chlorine ion, bromine ion
On, iodine ion, fluoride ion, nitrate ion, sulfuric acid
Ions, hydrogensulfate ions, phosphate ions, fluoroborate
On, perchlorate ion, thiocyanate ion, acetate ion
Ion, propionate ion, methanesulfonate ion, p
-Toluenesulfonate ion, trifluoroacetate ion
And trifluoromethanesulfonate ion
At least one anion selected from a group of 1 to 3 valent anions
Is an ion, a represents the ionic valence of X, and has an integer of 1 to 3
Is a number, m is a doping rate, and the value is 0 to 3.0.
is there. ) Is an organic electroluminescent element according to claim 1 or 2.
Child. 4. The indole derivative trimer comprises: [Chemical 3] (In the above formula, R₃₁~ R₄₅Is hydrogen and 1 to 24 carbon atoms
Straight chain or branched alkyl group, straight chain having 1 to 24 carbon atoms
Or a branched alkoxy group, a straight chain having 2 to 24 carbon atoms,
Is a branched acyl group, aldehyde group, carboxyl group, charcoal
Linear or branched carboxylic acid ester having a prime number of 2 to 24
Group, sulfonic acid group, straight or branched chain having 1 to 24 carbon atoms
Sulfonate group, cyano group, hydroxyl group, nitro group,
Amino group, amide group, dicyanovinyl group, alkyl (carbon
Linear or branched alkyl group having a prime number of 1 to 8) Oxical
Bonyl cyanovinyl group, nitrophenyl cyanovinyl group
And independently selected from the group consisting of halogen groups.
R is a substituent₃₁~ R ₄₂At least one of
One is a sulfonic acid group or a carboxyl group. Also X
^a-Is chlorine ion, bromine ion, iodine ion, fluorine
Ion, nitrate ion, sulfate ion, hydrogen sulfate ion,
Nitrate ion, borofluoride ion, perchlorate ion, thio
Cyanate ion, acetate ion, propionate ion,
Tan sulfonate ion, p-toluene sulfonate ion
Ion, trifluoroacetate ion, and trifluoromethane
Selected from a group of 1 to 3 valent anions consisting of sulfonate ions
Is at least one anion extracted, and a is an X ion.
Represents an valence number, is an integer of 1 to 3, and m is a doping rate.
The value is 0 to 3.0. ) Is a
The organic electroluminescent element according to any one of 1. 5. An indole derivative trimer is represented by: (In the above formula, R _{46 to} R ₅₀ are hydrogen and carbon atoms 1 to 24.
A straight chain or branched alkyl group, a straight chain or branched alkoxy group having 1 to 24 carbon atoms, a straight chain or branched acyl group having 2 to 24 carbon atoms, an aldehyde group, a carboxyl group, a straight chain group having 2 to 24 carbon atoms. Chain or branched carboxylic acid ester group, sulfonic acid group, linear or branched sulfonic acid ester group having 1 to 24 carbon atoms, cyano group, hydroxyl group, nitro group,
Each independently selected from the group consisting of an amino group, an amide group, a dicyanovinyl group, an alkyl (a linear or branched alkyl group having 1 to 8 carbon atoms) oxycarbonylcyanovinyl group, a nitrophenylcyanovinyl group and a halogen group. It is a substituent. 1.) An indole derivative trimer obtained by reacting at least one indole derivative represented by the formula 1) in a reaction mixture containing at least one oxidizing agent and at least one solvent. 5. The organic electroluminescent element according to any one of 4 above. 6. The organic electroluminescence device according to claim 1, wherein the indole derivative trimer has a laminated structure. 7. The organic electroluminescent device according to claim 1, wherein the organic layer is at least one light emitting layer. 8. The organic electroluminescent device according to claim 7, wherein the organic layer contains at least one hole transport layer. 9. The organic electroluminescent device according to claim 7, wherein the organic layer contains at least one electron transport layer.