JP2000192028A - Aromatic hydrocarbon compound and organic electroluminescent element prepared by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a high luminescent efficiency to be realized by forming an organic luminescent layer containing a specific aromatic hydrocarbon compound. SOLUTION: The organic luminescent layer is formed from a composition prepared by compounding 100 pts.wt. aromatic hydrocarbon compound represented by formula II (e.g. a compound represented by formula I) with 0.1-20 pts.wt. rebonding-site-forming substance (e.g. a styrylamine compound) having a fluorescent quantum yield of 0.3-1.0. The electroluminescent element comprises a pair of electrodes and the organic luminescent layer interposed between the electrodes. The aromatic hydrocarbon compound is prepared by converting a halide represented by formula II into a Grignard reagent and coupling the agent to a dibromo compound represented by formula IV. In the formulas, Ar1 and Ar2 are each arylene or a 4-30C hetrocycle containing O, N, S, or Si; Ar3 and Ar4 are each aryl or a 4-30C hetrocycle containing O, N, S, or Si; R is a bonding site to form a ring together with Ar2 or Ar3; n is 0-2; and m is 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel aromatic hydrocarbon compound and an organic electroluminescence device using the compound (hereinafter sometimes referred to as an organic EL device). More specifically, the present invention relates to an aromatic hydrocarbon compound having high utility as a constituent material of an organic EL device, and an organic EL device using the aromatic hydrocarbon compound and having excellent luminous efficiency.

[0002]

2. Description of the Related Art An organic EL device utilizing electroluminescence has characteristics of high visibility because it is self-luminous, and excellent impact resistance because it is a completely solid device. Therefore, it is used in fields such as thin film display elements, backlights of liquid crystal displays, and flat light sources.

[0003] The electroluminescent element currently put to practical use is a dispersion type electroluminescent element. Since this dispersion type electroluminescence element requires an AC voltage of several tens of volts or 10 kilohertz or more, its driving circuit is complicated. For these reasons, organic EL elements capable of reducing the driving voltage to about 10 volts and emitting light with high luminance have been actively studied in recent years. For example, C.I. W.
Tang and S.M. A. Van Slyke Ap
pl. Phys. Lett. , Vol. 51 pp. 9
13-915 (1987) and JP-A-63-26462.
Japanese Patent Application Laid-Open Publication No. 9-29139 proposes an organic thin film EL device having a laminated type of a transparent electrode / a hole injection layer / a light emitting layer / a back electrode. Holes can be efficiently injected into the light emitting layer. The light emitting layer used in such an organic EL device may be a single layer,
As described above, since the balance between the electron transporting property and the hole transporting property was not good, the performance was improved by laminating in multiple layers.

However, in order to form such a laminated structure, there are problems that the manufacturing process is complicated and the required time is long, and that there are many restrictions such as a requirement for each layer to be thin. Furthermore, in recent years, there has been an increasing demand for downsizing of information devices and the like and a shift to a portable type, and there has been an increasing demand for further lowering these drive voltages. Therefore, development of a light emitting material, a hole transport material, and the like has been attempted in order to reduce the weight and drive voltage. Anthracene is known as a light-emitting material, but since it is difficult to form a uniform thin film, derivatives into which various substituents are introduced have been proposed. For example, JP-A-4-178488, JP-A-6-228544, JP-A-6-228545, JP-A-6-228546, JP-A-6-228546, and JP-A-6-228548.
JP, JP-A-6-228549 and JP-A-8-311
Japanese Patent No. 442 proposes to use a condensed polycyclic aromatic hydrocarbon compound as a light emitting material for an organic EL device. However, the use of these compounds has a drawback that luminous efficiency is not sufficient.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides an aromatic hydrocarbon compound which exhibits high luminous efficiency when used as a constituent material of an organic EL device, and an organic EL device using the same. It is intended to provide an element.

[0006]

Means for Solving the Problems The present inventors have made various studies to solve the above problems, and as a result, have found that an aromatic hydrocarbon compound having a specific chemical structure achieves the above object. Based on these findings, the present invention has been completed. That is, the gist of the present invention is as follows. (1) An aromatic hydrocarbon compound represented by the following general formula [1].

[0007]

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[In the formula, Ar ¹ and Ar ² each independently represent an arylene group having 6 to 20 carbon atoms which may have a substituent, or any one of an oxygen atom, a nitrogen atom, a sulfur atom and a silicon atom. And Ar ³ and Ar ⁴ each independently represent an aryl group having 6 to 20 carbon atoms which may have a substituent, or an oxygen atom, a nitrogen atom, a sulfur atom, An aryl or silicon atom-containing heterocyclic ring having 4 to 30 carbon atoms, wherein Ar ³ and Ar ⁴ may be bonded to each other via a linking group to form a ring; ² or a bonding site forming a ring with either Ar ³ , wherein the ring is a carbon atom, a nitrogen atom,
A 5- or 6-membered ring is formed by a linking group containing any of an oxygen atom, a sulfur atom and a silicon atom, n is an integer of 0 to 2, and m is 0 or 1. (2) An organic electroluminescent device having an organic light emitting layer sandwiched between at least a pair of electrodes,
An organic electroluminescence device containing the aromatic hydrocarbon compound represented by the general formula [1]. (3) The method according to (2), wherein the aromatic hydrocarbon compound represented by the general formula [1] is mainly contained in an emission band.
3. The organic electroluminescent device according to 1.). (4) The organic electroluminescent device according to (2) or (3), wherein the aromatic hydrocarbon compound represented by the general formula [1] is contained in an organic light emitting layer. (5) The organic electroluminescent device according to any one of (2) to (4), wherein the organic light emitting layer further contains a substance for forming a recombination site. (6) The substance for forming a recombination site has a fluorescence yield of 0.3 to 1.
The organic electroluminescent device according to the above (2), wherein the organic electroluminescent device is a fluorescent substance of No. 0. (7) The method according to (5) or (6), wherein the recombination site forming substance is at least one compound selected from the group consisting of a styrylamine compound, a quinacridone derivative, a rubrene derivative, a coumarin derivative, and a pyran derivative. Organic electroluminescent element.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The aromatic hydrocarbon compound of the present invention is an aromatic hydrocarbon compound represented by the general formula [1]. In the aromatic hydrocarbon compound represented by the general formula [1], the arylene group having 6 to 20 carbon atoms represented by Ar ¹ and Ar ² includes a phenylene group, a naphthylene group, a biphenylene group, an anthranylene group, and a terphenylene group. And the like, and examples of the heterocyclic ring having 4 to 30 carbon atoms containing any of an oxygen atom, a nitrogen atom, a sulfur atom and a silicon atom include furan, thiophene,
Pyrrole, 2-hydroxypyrrole, benzofuran, isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole, isoindole, indolizine, carbazole, 2-hydroxypyran, 2-hydroxychromene, 1-hydroxy-2-benzopyran, Xanthene, 4-hydroxythiopyran, pyridine, quinoline, isoquinoline, 4-hydroxyquinolidine, phenanthridine, acridine, oxazole, isoxazole, thiazole, isothiazole, furazane, imidazole, pyrazole, benzimidazole, 1-hydroxyimidazole, 1,8-naphthyridine, pyrazine, limimidine, pyridazine, quinoxaline quinazoline, sinoline, phthalazine, purine, teridine, perimidine, 1,10-fe Nsurorin, thianthrene,
Examples include phenoxatin, phenoxazine, phenothiazine, phenazine, phenassazine, silacyclopentadiene, silabenzene, and the like.

The aryl groups having 6 to 20 carbon atoms represented by Ar ³ and Ar ⁴ of the same formula include phenyl, naphthyl, biphenyl, anthranyl, terphenyl, phenanthryl, pyrenyl, diphenylnaphthyl. Group, diphenylanthranyl group, styryl group, styrylphenyl group and the like. Among these hydrocarbon groups, a phenyl group, a naphthyl group, a naphthylene group, a biphenyl group, and an anthranyl group are preferred.

The substituents that Ar ^{1 to} Ar ⁴ may have include alkyl groups having 1 to 6 carbon atoms,
An alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 5 to 18 carbon atoms, an amino group substituted with an aryl group having 5 to 16 carbon atoms, a nitro group, a cyano group, an ester group having 1 to 6 carbon atoms, halogen Atoms. Examples of these alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec.
-Butyl group, tert-butyl group, various pentyl groups, various hexyl groups, and the like. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and an isobutoxy group. Groups, sec-butoxy group, tert-butoxy group, various pentyloxy groups, various hexyloxy groups, and the like.

A linking group forming a ring by bonding Ar ³ and Ar ⁴ to each other, or a link forming a ring by bonding R to one of Ar ^{2 and} Ar ³ with R as a bonding site. As the group, a single bond or the following

[0013]

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[R in the above formula represents an alkyl group having 1 to 4 carbon atoms, a phenyl group, a phenyl group having a C1 to C4 alkyl group as a substituent, or a phenoxy group. Wherein a ring is formed by a linking group having the following structure: Next, specific examples of the aromatic hydrocarbon compound represented by the general formula [1] include the following.

[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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The method for producing the aromatic hydrocarbon compound represented by the general formula [1] is, for example, as follows:
The following general formula [2]

[0022]

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[In the formula, Ar ² , Ar ³ , Ar ⁴ , R and m represent Ar ² , Ar ³ , A in the general formula [1].
It has the same meaning as r ⁴ , R and m. ] Is converted to a Grignard reagent, and then represented by the following general formula [3]

[0024]

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[In the formula, Ar ¹ and n represent the general formula [1]
Has the same meaning as Ar ¹ and n in Can be efficiently obtained by coupling the dibromo compound represented by the formula Next, the organic EL device of the present invention is constituted by sandwiching an organic light emitting layer between a pair of electrodes, and the device preferably contains the aromatic hydrocarbon compound in its light emitting band, especially in the organic light emitting layer. It is configured to be. A typical device configuration of this organic EL device is as shown below, but is not limited thereto.

Anode / light emitting layer / cathode anode / hole injection layer / light emitting layer / cathode anode / light emitting layer / electron injection layer / cathode anode / hole injection layer / light emitting layer / electron injection layer / cathode anode / organic semiconductor layer / Emitting layer / Cathode Anode / Organic semiconductor layer / Electron barrier layer / Emitting layer / Cathode Anode / Organic semiconductor layer / Emitting layer / Adhesion improving layer / Cathode Anode / Hole injection layer / Hole transporting layer / Emitting layer / Electron injection Layer / Cathode Among these various element configurations, those having the above configuration are preferably used. As the aromatic hydrocarbon compound represented by the general formula [1], a compound mainly contained in a light-emitting band, in particular, a light-emitting layer among these constituent elements is suitably used. The content ratio of the aromatic hydrocarbon compound in the light emitting layer was 30 to the entire light emitting layer.
It is preferably from 100 to 100% by weight.

The organic EL device is manufactured on a light-transmitting substrate. This light-transmitting substrate is a substrate that supports the organic EL element.
It is desirable that the transmittance of light in a visible region of 0 nm is 50% or more, and it is more preferable to use a smooth substrate. As such a translucent substrate, for example, a glass plate, a synthetic resin plate, or the like is suitably used. Examples of the glass plate include a plate formed of soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz, or the like. Examples of the synthetic resin plate include plates made of polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyether sulfide resin, polysulfone resin, and the like.

Next, as the above-mentioned anode, those using a metal, an alloy, an electrically conductive compound or a mixture thereof having a large work function (4 eV or more) as an electrode material are preferably used. A specific example of such an electrode material is Au.
And conductive materials such as CuI, ITO, SnO2, and ZnO. In order to form this anode, a thin film can be formed from these electrode substances by a method such as an evaporation method or a sputtering method. The anode desirably has such a property that, when light emitted from the light emitting layer is extracted from the anode, the transmittance of the anode to the emitted light is greater than 10%. The sheet resistance of the anode is several hundred Ω.
/ □ or less is preferred. Further, the thickness of the anode is selected in the range of usually 10 nm to 1 μm, preferably 10 to 200 nm, although it depends on the material.

The light emitting layer of the organic EL device of the present invention preferably has the following functions. Injection function; Function that can inject holes from the anode or hole injection layer when applying an electric field, and can inject electrons from the cathode or electron injection layer. Transport function: Transfers the injected charges (electrons and holes) to the electric field. The function of moving with the force of light Emission function; The function of providing a recombination field of electrons and holes and connecting it to light emission However, there is a difference between the ease of hole injection and the ease of electron injection. Although the transport ability represented by the mobility of holes and electrons may be large or small, it is preferable to transfer one of the charges. The aromatic hydrocarbon compound represented by the general formula [1] satisfies the above three conditions and can mainly form a light emitting layer.

As a part of the constituent material of the light emitting layer of the organic EL device, a recombination site forming substance can be used. This recombination site-forming substance is a substance that positively provides a place where electrons and holes injected from both poles respectively recombine, or recombination energy of electrons and holes does not occur, but recombination energy is propagated. It is a substance that provides a place to emit light. Therefore, by adding this recombination site-forming substance, electrons and holes are more intensively recombined in the vicinity of the center of the light emitting layer than in the case where the aromatic hydrocarbon compound is used alone. The light emission luminance can be further increased.

From the above, as the material for forming the recombination site used as the constituent material of the light emitting layer of the organic EL device of the present invention, those having a high fluorescence quantum yield are preferable, and the value thereof is preferably 0.3. A value of from 1.0 to 1.0 is preferred. Examples of such a recombination site-forming substance include one or a mixture of two or more selected from the group of styrylamine compounds, quinacridone derivatives, rubrene derivatives, coumarin derivatives, and pyran derivatives. As the recombination site forming substance, a conjugated polymer can be used, and in particular, a polyarylenevinylene derivative, an alkyl-substituted or alkoxy-substituted polyarylene or vinylene derivative having 1 to 50 carbon atoms, and the like can be given. Can be

Further, it is desirable that these recombination site forming substances are selected in consideration of the coloring property of the light emitting layer. For example, when a blue color is desired, it is preferable to use perylene or an amino-substituted distyrylarylene derivative. When a green color is desired, it is preferable to use a quinacridone derivative or a coumarin derivative. When a yellow color is desired, it is preferable to use a rubrene derivative or the like. Further, when orange or red-orange is desired, it is preferable to use a dicyanomethylpyran derivative or the like.

The compounding ratio of the recombination site forming substance is determined in consideration of the light emission luminance and the color developing property of the light emitting layer.
It is preferable to set the value in the range of 0.1 to 20 parts by weight with respect to 0 parts by weight. If the amount of the recombination site-forming substance is less than 0.1 part by weight, the emission luminance tends to decrease, while if it exceeds 20 parts by weight, the durability tends to decrease. Therefore, in order to better maintain the balance between the emission luminance and the durability in the organic EL element, the content of the aromatic hydrocarbon compound 100
The amount is preferably 0.5 to 20 parts by weight, more preferably 1.0 to 10 parts by weight based on parts by weight.

As a material for forming the organic light emitting layer of the organic EL device, the following compounds are used depending on a desired color tone in addition to the above. For example, in the case of emitting violet light from the ultraviolet region, a compound represented by the following general formula [4] is suitably used.

[0035]

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[In the above formula, X is the following general formula [5]

[0037]

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(Wherein n represents an integer of 2 to 5), and Y represents the following general formula [6]

[0039]

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The group represented by The phenyl group, phenylene group, and naphthyl group in the compound represented by the general formula [4] include an alkyl group having 1 to 4 carbon atoms,
4, a compound having one or more substituents such as an alkoxy group, a hydroxyl group, a sulfonyl group, a carbonyl group, an amino group, a dimethylamino group or a diphenylamino group may be used. When there are a plurality of these substituents, they may be bonded to each other to form a saturated 5- or 6-membered ring. Further, as for the form of this compound, a compound bonded to a phenyl group, a phenylene group, or a naphthyl group at a para position is preferable because it has good binding properties and a smooth deposited film is easily formed. Specific examples of the compound represented by the general formula [4] are as follows.

[0041]

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[0042]

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Among these compounds, p-quarterphenyl derivatives and p-quinkphenyl derivatives are particularly preferred. Further, in order to obtain blue to green light emission, for example, a benzothiazole-based, benzimidazole-based, benzoxazole-based fluorescent whitening agent, a metal chelated oxinoid compound, and a styrylbenzene-based compound can be used. Specific examples of these compounds include, for example, compounds disclosed in JP-A-59-194393. Still other useful compounds are described in Chemistry of Synthetic Soy (1971)
Listed on pages 628-637 and 640.

As the chelated oxinoid compound, for example, the compounds disclosed in JP-A-63-295695 can be used. Typical examples include tris (8-quinolinol) aluminum and the like.
-Hydroxyquinoline-based metal complexes, dilithium epintridione and the like can be mentioned as suitable compounds.

Further, as the styrylbenzene-based compound, for example, those disclosed in European Patent Nos. 0319881 and 0375358 can be used. And Japanese Patent Laid-Open No. 25279/1990.
The distyrylpyrazine derivative disclosed in Japanese Patent Publication No. 3 can also be used as a material for the light emitting layer. In addition, polyphenyl compounds disclosed in European Patent No. 0377715 can also be used as a material for the light emitting layer.

Further, in addition to the above-described fluorescent whitening agents, metal chelated oxinoid compounds and styrylbenzene compounds, for example, 12-phthaloperinone (J. App.
l. Phys., Vol. 27, L713 (1988)),
1,4-diphenyl-1,3-butadiene, 1,1,
4,4-tetraphenyl-1,3-butadiene (above A
pp. Phys. Lett., Vol. 56, L799 (1
990)), a naphthalimide derivative (JP-A-2-30)
No. 5886), perylene derivatives (JP-A-2-189)
890), oxadiazole derivatives (Japanese Unexamined Patent Publication No.
No. 2,167,791 or an oxadiazole derivative disclosed by Hamada et al. At the 38th Joint Lecture on Applied Physics, an aldazine derivative (Japanese Unexamined Patent Publication No. 2-220393).
), Pyrazirine derivatives (JP-A-2-220394)
), Cyclopentadiene derivatives (JP-A-2-28)
9675), pyrrolopyrrole derivatives (Japanese Unexamined Patent Publication No.
No. 296891), styrylamine derivatives (App
l. Phys. Lett., Vol. 56, L799 (199)
0), coumarin-based compounds (JP-A-2-191694), International Patent Publication WO90 / 13148 and App.
l. Phys. Lett., vol 58, 18, P198.
2 (1991) can also be used as a material for the light emitting layer.

In the present invention, an aromatic dimethylidin compound (European Patent No. 0388768) is particularly used as a material for the light emitting layer.
It is preferable to use those disclosed in Japanese Patent Application Laid-Open No. HEI 3-231970. As a specific example,
4'-bis (2,2-di-t-butylphenylvinyl)
Biphenyl, 4,4′-bis (2,2-diphenylvinyl) biphenyl, and the like, and derivatives thereof can be given.

Further, Japanese Patent Application Laid-Open No. 5-258882 and the like
General formula (Rs-Q) described _Two-Al-OL
[Wherein L is a carbon atom containing 6 to 2 carbon atoms containing a phenyl moiety.
4 hydrocarbons, OL is a phenolate ligand
And Q represents a substituted 8-quinolinolate ligand;
Is a substituted 8-quinolinolate ligand at the aluminum atom
Chosen to sterically hinder the binding of more than two
8-quinolinolate ring substituents]
Compounds are also included. Specifically, bis (2-methyl-8
-Quinolinolate) (para-phenylphenolate)
Luminium (III), bis (2-methyl-8-quinolyl)
Nolate) (1-naphtholate) aluminum (II)
I) and the like.

In addition, there is a method of obtaining a mixed light emission of blue and green with high efficiency using doping according to JP-A-6-9953. In this case, the host
Examples of the light emitting material and dopant include strong fluorescent dyes ranging from blue to green, such as coumarin-based fluorescent dyes and fluorescent dyes similar to those used as the above-described host. Specifically, a luminescent material having a distyrylarylene skeleton as a host, particularly preferably 4,4'-bis (2,2-diphenylvinyl) biphenyl, a dopant as diphenylaminovinylarylene, particularly preferably, for example, N, N-diphenyl Aminovinylbenzene can be mentioned.

The light emitting layer for emitting white light is not particularly limited, but the following can be used. One in which the energy level of each layer of the organic EL laminated structure is defined and light is emitted by utilizing tunnel injection (EP 0390551). A device utilizing a tunnel injection as in the above, and a white light emitting device is described as an example (Japanese Patent Laid-Open No. 3-23).
No. 0584).

Ones in which a light emitting layer having a two-layer structure is described (JP-A-2-220390 and JP-A-2-21)
No. 6790). The light-emitting layer is divided into a plurality of light-emitting layers, each of which is made of a material having a different emission wavelength (Japanese Patent Application Laid-Open No. 4-51491). A structure in which a blue light-emitting material (fluorescence peak: 380 to 480 nm) and a green light-emitting material (480 to 580 nm) are laminated and further containing a red phosphor (Japanese Patent Application Laid-Open No. 6-2071).
No. 70).

A structure in which the blue light emitting layer contains a blue fluorescent dye, the green light emitting layer has a region containing a red fluorescent dye, and further contains a green fluorescent material (Japanese Patent Laid-Open No. 7-1421)
No. 69). Among these, those having the above configuration are particularly preferable.
Further, as the red phosphor, those shown below are preferably used.

[0053]

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Next, as a method of forming a light emitting layer using the above materials, for example, a vapor deposition method, a spin coating method, an LB
A known method such as a method can be applied. The light emitting layer is
In particular, a molecular deposition film is preferable. Here, the molecular deposition film refers to a thin film formed by deposition from a material compound in a gaseous state or a film formed by solidification from a material compound in a solution state or a liquid phase state. Can be distinguished from a thin film (molecule accumulation film) formed by the LB method by a difference in an aggregated structure and a higher-order structure and a functional difference caused by the difference.

As disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, which is then thinned by a spin coating method or the like. By doing so, the light emitting layer can be formed. The thickness of the light emitting layer formed in this manner is not particularly limited and can be appropriately selected depending on the situation, but is usually preferably in the range of 5 nm to 5 μm. The light-emitting layer may be composed of one or more of the above-mentioned materials, or may be a laminate of light-emitting layers made of a different kind of compound from the light-emitting layer.

Next, the hole injecting / transporting layer is a layer that assists hole injection into the light emitting layer and transports it to the light emitting region. The hole injecting / transporting layer has a large hole mobility and usually has an ionization energy of 5.5 e.
V or less. As such a hole injecting / transporting layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable, and the mobility of holes is, for example, 10 ⁴ to 10 ⁶ V.
/ Cm when applying an electric field of at least 10 ⁻⁶⁶ cm ² / V
-Seconds are preferred. The material for forming the hole injecting / transporting layer by mixing with the aromatic hydrocarbon compound of the present invention is not particularly limited as long as it has the preferable properties described above. Any material can be selected from those commonly used as a transport material and known materials used in a hole injection layer of an organic EL device.

As a material for forming such a hole injection / transport layer, specifically, for example, a triazole derivative (see US Pat. No. 3,112,197) and an oxadiazole derivative (US Pat. 189,447), imidazole derivatives (JP-B-37-16096)
And polyarylalkane derivatives (US Pat. Nos. 3,615,402 and 3,820,98).
No. 9, 3,542, 544, JP-B-45-555, JP-B-51-10983, JP-A-51-93224, JP-A-55-17105, and 56- Nos. 4148, 55-108667, 55-15653, and 56-3665.
No. 6), pyrazoline derivatives and pyrazolone derivatives (U.S. Pat. Nos. 3,180,729 and 4,278,746; JP-A-55-88064).
JP-A-55-88065 and JP-A-49-1055.
Nos. 37, 55-51086, 56-80
No. 051, No. 56-88141, No. 57-4
Nos. 5545, 54-112637 and 55
-74546, etc.) and phenylenediamine derivatives (U.S. Pat. No. 3,615,404, JP-B-5).
Nos. 1-10105, 46-3712, and 4
JP-A-7-25336, JP-A-54-53435, JP-A-54-110536, and JP-A-54-11992
5 and the like, an arylamine derivative (US Pat. Nos. 3,567,450 and 3,180,703).
No. 3,240,597, No. 3,
Nos. 658,520, 4,232,103, 4,175,961, and 4,011.
2,376, JP-B-49-35702,
JP-A-39-27577, JP-A-55-144250.
JP-A-56-119132, JP-A-56-224
No. 37, West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (US Pat.
26,501), oxazole derivatives (disclosed in U.S. Pat. No. 3,257,203, etc.), styrylanthracene derivatives (JP-A-56-46).
234), fluorenone derivatives (Japanese Unexamined Patent Publication No.
4-110837), hydrazone derivatives (U.S. Pat. No. 3,717,462;
-59143, 55-52063, 5
No. 5-52064, No. 55-46760, No. 55-85495, No. 57-11350,
JP-A-57-148749, JP-A-2-311591
And stilbene derivatives (JP-A-61-21).
No. 0363, No. 61-228451, No. 6
1-114642, 61-72255, 62-47646, 62-36674,
JP-A-62-10652, JP-A-62-30255, JP-A-60-93455, JP-A-60-94462, JP-A-60-174747, and JP-A-60-1750
52, etc.), silazane derivatives (US Pat.
950, 950), polysilanes (Japanese Patent Laid-Open No.
No. 204996), an aniline-based copolymer (Japanese Unexamined Patent Publication No.
JP-A-282263) and conductive polymer oligomers (especially thiophene oligomers) disclosed in JP-A 1-211399.

As the material for the hole injecting / transporting layer, those described above can be used. Porphyrin compounds (those disclosed in JP-A-63-2959695), aromatic tertiary amine compounds and Styrylamine compounds (US Pat. No. 4,127,412;
-27033, 54-58445, 5
4-149634, 54-64299,
No. 55-79450, No. 55-144250, No. 56-119132, No. 61-29555
No. 8, No. 61-98353, No. 63-295
No. 695) and aromatic tertiary amine compounds can also be used.

Further, for example, 4,4′-bis (N- (1-naphthyl) -N-phenyl having two condensed aromatic rings in the molecule described in US Pat. No. 5,061,569. Amino) biphenyl and JP-A-4-308688
No. 4,4 ', 4 "-tris (N- (3-methylphenyl) -N-phenylamino) triphenylamine in which three triphenylamine units described in JP-A No. Further, in addition to the above-mentioned aromatic dimethylidin-based compound shown as the material for the light emitting layer, inorganic compounds such as p-type Si and p-type SiC can also be used as the material for the hole injection / transport layer. .

In order to form the hole injecting / transporting layer, the above-mentioned compound may be thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, and an LB method. In this case, the thickness of the hole injection / transport layer is not particularly limited, but is usually 5 nm to 5 μm.
If the hole injection / transport layer contains the aromatic hydrocarbon compound of the present invention in the hole transport zone, one of the above-described materials is used.
May be composed of one or more layers consisting of two or more species,
Further, a layer obtained by laminating a hole injection / transport layer composed of a compound different from the hole injection / transport layer may be used.

The organic semiconductor layer is a layer which assists hole injection or electron injection into the light emitting layer, and is 10 ^-10 S / c.
Those having a conductivity of at least m are preferred. Examples of the material for such an organic semiconductor layer include thiophene-containing oligomers, conductive oligomers such as arylamine-containing oligomers described in JP-A-8-193191, and conductive dendrimers such as arylamine-containing dendrimers. .

Next, the electron injecting layer is a layer which assists the injection of electrons into the light emitting layer, has a high electron mobility, and the adhesion improving layer is one of the electron injecting layers in which the adhesion to the cathode is particularly high. It is a layer made of a good material. As a material used for the electron injection layer, a metal complex of 8-hydroxyquinoline or a derivative thereof is preferable. As a specific example of the metal complex of 8-hydroxyquinoline or a derivative thereof, a metal chelate oxinoid compound containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline), for example, tris (8-quinolinol) aluminum is electron-injected. It can be used as a material.

The oxadiazole derivatives are represented by the following general formulas [7] to [7].

[9],

[0064]

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[Wherein Ar ¹ , Ar ² , Ar ³ , A
r ⁵ , Ar ⁶ , and Ar ⁹ each independently represent a substituted or unsubstituted aryl group, and may be the same or different from each other. Ar ⁴ , Ar ⁷ , and Ar ⁸ are
Each independently represents a substituted or unsubstituted arylene group, which may be the same or different. ] The electron transfer compound represented by these is mentioned.

These general formulas [7] to

Examples of the aryl group in [9] include a phenyl group, a biphenyl group, an anthranyl group, a perylenyl group, and a pyrenyl group. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthranylene group, a perylenylene group, and a pyrenylene group. Examples of the substituent on these include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a cyano group. As the electron transfer compound, those having good thin film forming properties are preferably used.

The following are specific examples of these electron transfer compounds.

[0068]

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Next, as the cathode, a metal, an alloy, an electrically conductive compound having a small work function (4 eV or less), and a mixture thereof as an electrode material are used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium-silver alloy, aluminum / aluminum oxide, aluminum-lithium alloy, indium, and rare earth metals. This cathode can be manufactured by forming a thin film from these electrode substances by a method such as vapor deposition or sputtering.

Here, when the light emitted from the light emitting layer is taken out from the cathode, it is preferable that the transmittance of the cathode with respect to the emitted light be greater than 10%. Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10
nm to 1 μm, preferably 50 to 200 nm. Next, with respect to the method for producing the organic EL device of the present invention, an anode, a light emitting layer, a hole injection layer if necessary, and an electron injection layer if necessary are formed by the above materials and methods. A cathode may be formed. Further, the organic EL device can be manufactured in the reverse order from the cathode to the anode.

Hereinafter, an example of manufacturing an organic EL device having a structure in which an anode / a hole injection layer / a light emitting layer / an electron injection layer / a cathode is sequentially provided on a light-transmitting substrate will be described. First, a thin film made of an anode material is formed on a suitable light-transmitting substrate so as to have a thickness of 1 μm or less, preferably in a range of 10 to 200 nm.
An anode is formed by an evaporation method or a sputtering method. Next, a hole injection layer is provided on the anode. As described above, the hole injection layer can be formed by a method such as a vacuum evaporation method, a spin coating method, a casting method, and an LB method. However, a uniform film is easily obtained and pinholes are not easily generated. From the viewpoint of the above, it is preferable to form by a vacuum evaporation method. When the hole injection layer is formed by a vacuum evaporation method, the deposition conditions vary depending on the compound to be used (the material of the hole injection layer), the crystal structure and the recombination structure of the target hole injection layer, etc. Source temperature 50 to 450 ° C., degree of vacuum 10 ⁻⁷ to 10 ⁻³ torr, deposition rate 0.01 to 50
nm / sec, substrate temperature -50 to 300 ° C, film thickness 5 nm to 5
It is preferable to appropriately select within the range of μm.

Next, a light emitting layer is provided on the hole injection layer. This light emitting layer can also be formed by thinning the organic light emitting material using a desired organic light emitting material by a method such as a vacuum evaporation method, a sputtering method, a spin coating method, or a casting method, but a uniform film is obtained. It is preferable to form them by a vacuum deposition method from the viewpoint that they are easily formed and pinholes are hardly generated. When the light emitting layer is formed by a vacuum deposition method, the deposition conditions vary depending on the compound used, but can be generally selected from the same condition range as the formation of the hole injection layer.

Next, an electron injection layer is provided on the light emitting layer. In this case as well, like the hole injection layer and the light emitting layer, it is preferable to form the film by a vacuum evaporation method because it is necessary to obtain a uniform film. The deposition conditions can be selected from the same condition ranges as for the hole injection layer and the light emitting layer. The aromatic hydrocarbon compound of the present invention varies depending on which of the organic compound layers is contained, but when a vacuum evaporation method is used, co-evaporation with another material can be performed. When the spin coating method is used, it can be contained by mixing with another material.

Finally, an organic EL element can be obtained by laminating a cathode. The cathode is made of a metal, and an evaporation method or sputtering can be used. However, in order to protect the underlying organic layer from damage during film formation, a vacuum deposition method is preferable. The production of the above organic EL element is as follows.
It is preferable to produce from the anode to the cathode consistently by one evacuation.

When a DC voltage is applied to the organic EL device, light emission can be observed by applying a voltage of 5 to 40 V with the anode having a positive polarity and the cathode having a negative polarity. Also, even if a voltage is applied in the opposite polarity, no current flows and no light emission occurs.
Further, when an AC voltage is applied, uniform light emission is observed only when the anode has a positive polarity and the cathode has a negative polarity. In this case, the waveform of the applied AC may be arbitrary.

[0076]

Next, the present invention will be described in more detail with reference to examples. [Example 1] Under an argon gas atmosphere, 20 g of phenylacetylene and 50 ml of tetrahydrofuran were charged into a reaction vessel, and then 15 ml of a hexane solution of n-butyllithium (1.6 molar concentration) was added at -70 ° C. Furthermore, 45 g of p-dibromobenzene
Was added and the mixture was returned to room temperature and reacted for 3 hours.

The obtained reaction solution was poured into water, extracted with toluene, the extract was dried over anhydrous magnesium sulfate, and then concentrated using a rotary evaporator. The residue obtained here was purified by silica gel column chromatography to obtain 17 g of 4-bromodiphenylacetylene. Then, the 4-bromodiphenylacetylene 17
g was mixed with 18 g of 2-iodophenol, 3 g of copper iodide, and 100 ml of dimethylformamide, and reacted under heating and reflux for 4 hours. After filtering the obtained reaction solution and distilling the solvent off under reduced pressure, the obtained residue was purified by silica gel column chromatography to obtain 3 g of 2-phenyl-3- (4-bromophenyl) benzofuran.

Next, 1 g of magnesium powder and 20 ml of tetrahydrofuran were charged into a reactor under an argon gas stream, and 2 g of 2-phenyl-3- (4-bromophenyl) benzofuran was dissolved in 20 ml of tetrahydrofuran. The solution was added dropwise, and reacted for 3 hours under reflux with heating. Then, under an argon gas stream,
9,10-Dibromoanthracene (Tokyo Kasei) 1g
And 5 ml of a toluene solution of diisobutylaluminum hydride (manufactured by Aldrich; 1 molar solution), 0.2 g of palladium dichloride triphenylphosphine complex (manufactured by Tokyo Chemical Industry), and 100 ml of tetrahydrofuran were charged into a reactor, and heated under reflux. For 4 hours.

Then, the Grignard reagent obtained above was added dropwise to the obtained reaction solution, and the mixture was reacted under heating and refluxing for 48 hours. The reaction product liquid obtained in this way is
The mixture was poured into 0 ml, and the precipitated crystals were collected by filtration. The crystals were further purified by a silica gel column to obtain 0.45 g of the desired product. FD-MS measurement of the obtained target compound showed that C ₅₄ H ₃₄ O ₂ = 714.
714 was obtained, which was identified as an aromatic hydrocarbon compound having the following chemical structure.

[0080]

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Example 2 Under an argon gas atmosphere, 1.5 g of sodium hydride and 50 ml of tetrahydrofuran were charged into a reaction vessel, and 10 g of ethylbenzoyl acetate (manufactured by Aldrich) was dissolved in 50 ml of tetrahydrofuran. Drop the solution,
After reacting for 2 hours with stirring, 12 g of p-dibromobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was further added to tetrahydrofuran 20
The solution dissolved in milliliter was dropped and reacted for 4 hours.

The obtained reaction solution was poured into water, extracted with ethyl acetate, and the extract was dried over anhydrous magnesium sulfate and concentrated with a rotary evaporator. The residue obtained here was purified by silica gel column chromatography to obtain 7 g of α- (P-bromophenyl) ethylbenzoyl acetate. Then, 5 g of aluminum chloride, 2 g of phenol, and 20 ml of methylene chloride were charged into another reactor, and the α- (P-
7 g of (bromophenyl) ethylbenzoyl acetate was added little by little, and the mixture was reacted with stirring for 4 hours.

The obtained reaction solution was poured into ice water, extracted with methylene chloride, and the extract was dried over anhydrous magnesium sulfate and concentrated by a rotary evaporator. The residue obtained here was purified by silica gel column chromatography to obtain 2.2 g of 3- (P-bromophenyl) -4-phenylcoumarin. Next, 1 g of magnesium powder and 20 g of tetrahydrofuran were added under an argon gas stream.
Milliliter was charged to the reactor, and 3 parts obtained above were added thereto.
-(P-bromophenyl) -4-phenylcoumarin 2g
Was dissolved in 20 ml of tetrahydrofuran, and the mixture was reacted for 3 hours under reflux with heating.

Then, under an argon gas flow, 4,4'-
0.7 g of dibromobiphenyl (manufactured by Tokyo Chemical Industry Co., Ltd.), 5 ml of a toluene solution of diisobutylaluminum hydride (manufactured by Aldrich Co., 1 molar solution), 0.2 g of palladium dichloride triphenylphosphine complex (manufactured by Tokyo Chemical Industry Co., Ltd.), and tetrahydrofuran 10
0 ml was charged into the reactor and reacted for 4 hours under reflux.

Then, the Grignard reagent obtained above was added dropwise to the obtained reaction solution, and the mixture was reacted under heating and refluxing for 48 hours. The reaction product liquid obtained in this way is
The mixture was poured into 0 ml, and the precipitated crystals were collected by filtration. The crystals were further purified by a silica gel column to obtain 0.5 g of the desired product. FD-MS measurement of the obtained target compound showed that C ₄₂ H ₂₆ O ₄ = 594.
On the other hand, a peak of 594 was obtained, which was confirmed to be an aromatic hydrocarbon compound having the following chemical structure.

[0086]

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Example 3 A glass substrate (size: 25 mm × 75 mm × 1.1) was used as a light-transmitting substrate of an organic EL device.
mm). On this glass substrate, a transparent anode made of indium tin oxide was provided. The transparent anode was coated to a thickness of about 750 angstroms.

Next, the glass substrate provided with the transparent anode was placed in a vacuum deposition apparatus (manufactured by Nippon Vacuum Engineering Co., Ltd.) and
The pressure was reduced to 0 ^-6 torr. Then, on this transparent anode, copper phthalocyanine was deposited to a thickness of 300 Å to form a hole injection layer. The deposition rate at this time was 2 Å / sec. Next, on this hole injection layer,

[0089]

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The above compound was deposited to a thickness of 200 Å to form a hole transport layer. The deposition rate at this time was 2 Å / sec. Then, the aromatic hydrocarbon compound obtained in Example 1 and the following

[0091]

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A compound having the thickness of 400 Å was formed by co-evaporation of the above compound. In this case, the deposition rate of the aromatic hydrocarbon compound obtained in Example 1 was set to 50 Å / sec,
The deposition rate of bis [2- (4- (N, N-diphenylamino) phenyl) vinyl] biphenyl was 1 Å / sec.

Further, on this light emitting layer,

[0094]

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The aluminum (Tris (8-quinolinol)) was deposited at a deposition rate of 2 Å / sec to form an electron transport layer. Finally, a cathode having a thickness of 2000 Å was formed on the electron transporting layer by simultaneously vapor-depositing aluminum and lithium. The aluminum deposition rate was 10 angstroms / second, and the lithium deposition rate was 0.1 angstroms / second. Organic EL obtained in this way
When the device was driven at a voltage of 6 V, the current density was:
It was 1.1 mA / cm ² and emitted blue light of 130 cd / m ² . The luminous efficiency in this case was 6.2 lumen / W.

Example 4 In Example 3, the aromatic hydrocarbon compound obtained in Example 2 was used in place of the aromatic hydrocarbon compound obtained in Example 1 used for forming the light emitting layer. Otherwise in the same manner as in Example 3, an organic EL device was manufactured. The organic EL device obtained here was also driven at a voltage of 6V. In this device, the current density is 1.1
mA / cm ² , and emitted blue light of 127 cd / m ² . The luminous efficiency in this case was 6.0 lumen / W.

Comparative Example 1 The procedure of Example 3 was repeated, except that the aromatic hydrocarbon compound obtained in Example 1 was used to form the light emitting layer.

[0098]

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An organic EL device was produced in the same manner as in Example 3, except that a known aromatic hydrocarbon compound was used as the light emitting material represented by The organic EL device obtained here was also driven at a voltage of 6V. In this element,
The current density was 1.2 mA / cm ² and 44 cd / m ²
It emitted light. And the luminous efficiency in this case is
It was 1.9 lumens / W.

Comparative Example 2 The procedure of Example 3 was repeated, except that the aromatic hydrocarbon compound obtained in Example 1 was used to form the light emitting layer.

[0101]

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An organic EL device was produced in the same manner as in Example 3, except that a known aromatic hydrocarbon compound was used as the light emitting material represented by The organic EL device obtained here was also driven at a voltage of 6V. In this element,
The current density was 1.2 mA / cm ² and 72 cd / m ²
It emitted light. And the luminous efficiency in this case is
3.1 lumen / W.

[0103]

The aromatic hydrocarbon compound of the present invention has high utility as a constituent material of an organic EL device, and an organic EL device produced by using this compound as a constituent material thereof, particularly as a material for forming a light emitting layer, Low voltage driving is possible, and high luminous efficiency is obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07D 311/12 C07D 311/12 4H049 519/00 519/00 H05B 33/14 H05B 33/14 B // C07C 13/54 C07C 13/54 13/58 13/58 13/62 13/62 13/70 13/70 C07D 333/18 C07D 333/18 333/54 333/54 C07F 7/08 C07F 7/08 C F term (Reference) 3K007 AB03 AB06 CA01 CA05 DA00 DA01 DB03 EB00 FA01 FA03 4C037 PA06 4C062 EE07 4C072 MM08 4H006 AA01 AA03 AB92 4H049 VN01 VP01 VQ08 VQ84 VR24 VU24 VU29 VW01

Claims (7)

[Claims] 1. An aromatic hydrocarbon compound represented by the following general formula [1]. Embedded image [Wherein, Ar ¹ and Ar ² each independently contain an arylene group having 6 to 20 carbon atoms which may have a substituent, or an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom. A heterocyclic ring having 4 to 30 carbon atoms, and Ar ³
And Ar ⁴ each independently represent an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryl group having 4 to 30 carbon atoms containing any of an oxygen atom, a nitrogen atom, a sulfur atom and a silicon atom. A heterocyclic ring in which Ar ³ and Ar ⁴ may be bonded to each other via a linking group to form a ring;
Represents a bonding site that forms a ring with either Ar ² or Ar ³ , and the ring is formed by a linking group containing any one of a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, and a silicon atom.
Forms a 6-membered or 6-membered ring, n is an integer of 0 to 2, m is 0
Or 1. ] 2. An organic electroluminescence device having an organic light emitting layer sandwiched between at least a pair of electrodes, comprising an aromatic hydrocarbon compound represented by the general formula [1] according to claim 1. Organic electroluminescent element. 3. The organic electroluminescent device according to claim 2, wherein the aromatic hydrocarbon compound represented by the general formula [1] according to claim 1 is mainly contained in an emission band. 4. The organic electroluminescent device according to claim 2, wherein the aromatic hydrocarbon compound represented by the general formula [1] according to claim 1 is contained in an organic light emitting layer. 5. The organic electroluminescent device according to claim 2, wherein the organic light emitting layer further contains a recombination site forming substance. 6. The method according to claim 6, wherein the substance capable of forming a recombination site has a fluorescence yield of 0.
6. The organic electroluminescent device according to claim 5, wherein the organic electroluminescent device is a fluorescent material having 3 to 1.0. 7. The organic electroluminescent device according to claim 5, wherein the recombination site forming substance is at least one compound selected from the group consisting of a styrylamine compound, a quinacridone derivative, a rubrene derivative, a coumarin derivative, and a pyran derivative. Luminescent element.