JP2000007604A - Distyrylarylene derivative and organic electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound capable of realizing improvements in an light generation efficiency and a low driving voltage, and useful as a light generating material for an organic electroluminescence element and also as a positive hole transporting material. SOLUTION: This styrylarylene derivative is a compound of formula I [An is a divalent group consisting of a (substituted) condensed ring containing at least 3 rings; Ar1 and Ar2 are each a single bond, a 6-30C arylene or a polyarylene; R1 to R4 are each H, a 6-30C aryl or a polyaryl; wherein R1 to R4 are each at least triply substituted with an amino or oxy substituent, or substituted to either R1 or R2, or substituted to R3 or R4; and the above substituents are a 1-30C alkyl, a 1-30C alkoxy, a 6-18C aryloxy or the like and are allowed to be substituted singly or plurally], e.g. a compound of formula II. A light generating layer is constituted by the above compound and a re-combined site-forming material such as 4,4'-bis[2- 4-(N,N-diphenylamino)- phenyl}vinyl]biphenyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distyrylarylene derivative as a novel styryl compound, and an organic electroluminescent device (hereinafter, referred to as an organic EL device) using the distyrylarylene derivative.

[0002]

2. Description of the Related Art EL (electroluminescence) elements utilizing electroluminescence have characteristics of good visibility due to self-emission and excellent impact resistance because they are completely solid. It is used for backlights of liquid crystal displays, flat light sources, and the like. The EL devices that are currently mainly put into practical use are inorganic dispersion-type EL devices. This inorganic dispersion type EL element has a capacity of several tens of volts, 10 kHz.
Since an AC voltage of z or more is required, the driving circuit is complicated.

On the other hand, an organic thin film EL element requires a driving voltage of 1
In recent years, studies have been actively conducted to reduce the voltage to about 0 V and emit light with high luminance.
L-elements have been developed. The basic element configuration of the organic thin film EL element is a transparent electrode / light-emitting layer / back (opposite) electrode. As described above, the light-emitting layer may be a single layer, but the balance between the electron transporting property and the hole transporting property is poor, so that the performance is enhanced by forming the organic compound layer into multiple layers (CW
Tang and SAVan Slyke, Appl.Phys, Lett., Vol. 51, pp. 9
13-915 (1987); JP-A-63-264692). The element configuration of this stacked organic thin film EL element is, for example, a transparent electrode /
It is a hole injection layer / light emitting layer / back electrode, and holes can be efficiently injected into the light emitting layer by the hole injection layer.

[0004]

In the method of forming an organic compound layer such as a light emitting layer and a hole injection layer into multiple layers, each layer must be sequentially formed by a vacuum deposition method or the like, so that it takes time to manufacture the device. Take it. Further, since each layer must be formed in a uniform and thin film form, the material of the organic compound layer is required to have excellent thin film properties, and there is a problem that usable materials are limited. For example, even if the luminous efficiency is high, a material having poor thin film properties cannot be adopted as a luminescent material.

In order to solve such a problem, there has been proposed an organic EL device in which a light emitting layer is constituted by an organic compound having both properties of a hole transporting ability and an electron transporting ability (Japanese Patent Laid-Open Publication No. Hei. No. 21070). However, Japanese Patent Laid-Open No. 2-2
The organic compound disclosed in Japanese Patent No. 1070 has a thin film property, but has poor heat resistance and low luminous efficiency, and even if this organic compound is used, sufficient performance as a display element cannot be obtained.

[0006] In recent years, there has been an increasing demand for organic EL elements to have lower driving voltages for use as portable information equipment. For this reason, attempts have been made to lower the drive voltage by improving the hole injection layer and the hole transport layer, but satisfactory results have not been obtained.

An object of the present invention is to provide a distyryl arylene derivative and an organic electroluminescent device which can realize an improvement in luminous efficiency and a lower driving voltage.

[0008]

Means for Solving the Problems As a result of intensive studies by the present inventors to achieve the above object, the present inventors have found that an electron transporting group and a hole transporting group are arranged in the same molecule in a well-balanced manner. Thus, it was found that an organic EL device having high luminous efficiency can be obtained with only one layer made of this compound. Based on this finding, as a result of further investigation, it was found that an amino group or an oxy substituent was arranged in the compound molecule as a group for efficiently injecting and transporting holes, and at least three groups for electron transport were provided. It has been found that a divalent group consisting of a substituted or unsubstituted fused ring containing a ring is promising. In addition, when these amino groups or oxy substituents and a divalent group comprising a substituted or unsubstituted condensed ring containing at least three rings are contained in one molecule of the compound, the ionization potential is reduced and the efficiency is reduced. It has been found that holes can be well injected and a low driving voltage can be achieved. The present invention has been completed based on these findings.

Specifically, the present invention relates to a compound represented by the general formula [I]:

[0010]

Embedded image

(In the formula, An represents a divalent group comprising a substituted or unsubstituted fused ring containing at least three rings.
Ar ₁ and Ar ₂ each independently represent any one of a single bond, arylene having 6 to 30 carbon atoms, and polyarylene which is an aggregate of arylene. R _{1 to} R ₄ independently represent any one of hydrogen, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and a polyaryl group which is an aggregate of the aryl groups. R ₁ to R ₄ is an amino group or a substituent, for either is at least trisubstituted or more, or, R ₁
And R ₂ , or R ₃ and R ₄ . Here, the substituent is a group having 1 carbon atom.
An alkyl group having from 30 to 30, an alkoxy group having from 1 to 30 carbon atoms,
Represents an aryloxy group having 6 to 18 carbon atoms, an aryl group having 6 to 20 carbon atoms, an amino group, a cyano group, a nitro group, a hydroxyl group, or a halogen atom. These substituents may be single or plurally substituted. The present invention provides a distyrylarylene derivative represented by the following formula:

Here, single substitution means, for example, when Ar ₁ is phenylene, one methyl group is substituted as a substituent, and plural substitution means, for example, when phenylene has three methyl groups. And four or four phenylene groups are substituted with one methyl group and one ethyl group.

The distyrylarylene derivative of the present invention represented by the above general formula [I] is effective as a constituent material of an organic EL device. That is, the organic EL device of the present invention includes the distyrylarylene derivative represented by the general formula [I], and a pair of electrodes sandwiching the distyrylarylene derivative.

That is, since the compound represented by the general formula [I] (distyrylarylene derivative) generally has an ionization energy of less than about 5.7 eV, a suitable anode metal or anode compound is selected as an electrode (anode). Then, an element that can relatively easily inject holes can be obtained. Also,
Since the distyrylarylene derivative of the present invention has an electron affinity greater than about 2.8 eV, if an appropriate cathode metal or cathode compound is selected as an electrode (cathode), it is relatively easy to inject electrons, and it is relatively easy to inject electrons. The hole transport capacity is also excellent. Further, since the compound represented by the general formula (I) has strong fluorescence in a solid state, it is formed at the time of recombination of an electron and a hole in the compound or its aggregate or a crystal of the compound. High ability to convert excited state to light.

For this reason, by using the distyryl arylene derivative represented by the general formula [I] as a constituent material of the organic compound layer of the organic EL device, excellent luminous efficiency can be obtained even with a single layer and low voltage can be obtained. Can be realized.
Therefore, an excellent device performance can be obtained with a single layer even if the device configuration is not multilayered, so that the device can be easily manufactured.

Although the structure of the organic EL element has various modes, it is basically based on the structure in which a light emitting layer is sandwiched between the above-mentioned pair of electrodes (anode and cathode), and the above-mentioned distyryl is used as a constituent material of the light emitting layer. It is desirable to use an arylene derivative.

The distyrylarylene derivative may be used alone as the light-emitting layer. However, in order to further enhance the luminous efficiency, the light-emitting layer preferably contains a substance for forming a recombination site together with the distyrylarylene derivative. Here, the recombination site forming substance is a substance (sometimes called a dopan) that positively provides a place where electrons and holes injected from both electrodes are recombined with each other, or an electron and a positive electrode. It refers to a substance that does not generate recombination itself with the pores but provides a place where light is emitted when recombination energy is propagated. That is, the recombination site-forming substance is a substance that has a relatively high fluorescence quantum yield added to supplement the emission luminance in the light-emitting layer when the emission luminance in the light-emitting layer is poor only by using the molecular compound alone. By adding a forming substance, electrons and holes can be recombined intensively near the center of the light-emitting layer, so that emission luminance can be increased.

As described above, the substance for forming a recombination site is preferably made of a material having a high fluorescence quantum yield, and specifically, a fluorescent material having a fluorescence yield in the range of 0.3 to 1.0. It is desirable that it be made of at least one selected from the following. As a fluorescent material satisfying such a range of the fluorescence quantum yield, a styrylamine-based compound, a quinacridone derivative, a rubrene derivative, a coumarin derivative, and a pyran derivative can be employed. That is, any of these fluorescent materials may be used alone, or two or more of them may be used in combination as the recombination site forming substance.

A hole transport layer may be interposed between the above-mentioned light emitting layer and the electrode, if necessary, and a distyryl arylene derivative may be used as a constituent material of the hole transport layer.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION <1> Distyrylarylene Derivative In the general formula [I], specific examples of An include a divalent group composed of anthracenediyl, tetracenediyl and pyrene, a divalent group composed of perylene, A divalent group composed of triphenylene and a divalent group composed of coronene are preferred. Particularly preferred is anthracenediyl.

In the general formula [I], Ar ₁ and Ar ₂ each independently represent a single bond, a group having 6 to 3 carbon atoms.
0 arylene and polyarylene which is an aggregate of arylene. These arylenes and polyarylenes may be substituted or unsubstituted. If the number of carbon atoms of the arylene is less than 6, the desired arylene cannot be formed. If the number of carbon atoms exceeds 30, the synthesis takes time and the deposition may be difficult. As arylene, for example, phenylene, biphenylene, naphthylene, terphenylene, anthracenediyl, quarterphenylene, tetracenediyl,
Alternatively, the following groups may be mentioned.

[0022]

Embedded image

The polyarylene is a group in which arylene having 6 to 30 carbon atoms is combined and linked, and specifically, diphenylanthracenediyl, binaphthylene,
Bianthracendiyl, Bianthril terphenylene,
Dibiphenylanthracenediyl, a group represented by the following chemical formula 4, and a group linked by combining the groups represented by the chemical formula 4

[0024]

Embedded image

In the general formula [I], R _{1 to} R ₄ are each independently hydrogen, substituted or unsubstituted carbon atoms having 6 to 3 carbon atoms.
0 represents an aryl group or a polyaryl group that is an aggregate of aryl groups. Specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a terphenyl group, an anthranyl group, a styryl group, and a styrylphenyl group.

Further, R _{1 to} R ₄ in the general formula [I] are desirably at least three or more, particularly preferably four or more, by an amino group or an oxy substituent. Even when R _{1 to} R ₄ are not totally substituted by 3 or more by amino group or oxy substituent, R ₁ and R ₂ are substituted with R ₁ and R ₂ or R ₃
And only needs to be replaced with R _4.

Here, as the amino group, for example, NH
_Two groups, an alkylamino group, an arylamino group and the like can be employed. The alkylamino group has the general formula (II)

[0028]

Embedded image

(Wherein, R ₅ and R ₆ each represent an alkyl group having 1 to 6 carbon atoms). Examples of the alkyl group in the general formula [II] include a methyl group, an ethyl group, a propyl group, and a butyl group. An arylamino group has the general formula (III)

[0030]

Embedded image

(Wherein, Ar ₃ and Ar _{4 each} have 6 to ₃ carbon atoms)
Represents an aryl group of 0, which may be substituted or unsubstituted. ).

Examples of the oxy substituent include groups bonded via oxygen, such as an alkoxy group and an aryloxy group. The alkoxy group has the general formula (IV)

[0033]

[Image Omitted] R ₇ -O- ... [IV]

(In the formula, R ₇ represents an alkyl group having 1 to 30 carbon atoms.) Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. An aryloxy group has the general formula (V)

[0035]

Embedded image Ar ₅ —O—... [V]

(Wherein, Ar ₅ represents an aryl group having 6 to 30 carbon atoms or a polyaryl group which is an aggregate of aryl groups, and these may be substituted or unsubstituted). You.

As specific examples of the distyrylarylene derivative represented by the general formula [I], styryl compounds represented by the following chemical formulas [1] to [38]
Compounds [1] to [38] in some cases). Note that the present invention is not limited to these.

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image

[0041]

Embedded image

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image

<2> Organic EL element (1) Element structure of organic EL element Organic EL using the distyryl arylene derivative of the present invention
The element basically has an element structure in which a light emitting layer which is an organic compound layer is sandwiched between a pair of electrodes (anode and cathode), and if necessary, a hole injection layer and a hole transport layer Organic compound layers such as an electron injection layer, an electron transport layer, an organic semiconductor layer, an electron barrier layer, and an adhesion improving layer can be interposed between the light emitting layer and the electrode.

As a specific device configuration of such an organic EL device, the following representative configuration can be given.
The organic EL device of the present invention is not limited to this. Anode / light-emitting layer / cathode anode / hole-transport layer / light-emitting layer / cathode anode / hole-injection layer / hole-transport layer / light-emitting layer / cathode anode / hole-injection layer / hole-transport layer / light-emitting layer / electron transport Layer / cathode anode / hole injection layer / hole transport layer / emission layer / electron transport layer / electron injection layer / cathode anode / emission layer / electron injection layer / cathode anode / organic semiconductor layer / emission layer / cathode anode / organic Semiconductor layer / Electron barrier layer / Emitting layer / Cathode Anode / Hole injection layer / Emitting layer / Adhesion improving layer / Cathode

It is preferable that the organic compound layer and the electrode are supported on a substrate, regardless of the element configuration. As the substrate, a substrate conventionally used for an EL element may be appropriately used. For example, a substrate made of glass, transparent plastic, quartz, or the like can be used.

The distyryl arylene derivative represented by the above general formula [I] is effective as a light emitting material and a hole transporting material in an organic EL device. The distyrylarylene derivative to be used is used as a constituent material of at least one of the light emitting layer and the hole transport layer.

(2) Light-Emitting Layer The light-emitting layer is formed by thinning a distyrylarylene derivative represented by the general formula [I] by a known method such as a vapor deposition method, a spin coating method and a casting method. It is preferable to use a molecular deposition film. Here, a molecular deposited film is a thin film formed by depositing a distyrylarylene derivative of the general formula (I) from a gaseous state,
A thin film formed by solidifying the compound from a solution state or a liquid phase state, for example, a vapor-deposited film. The molecular deposition film is usually distinguished from a thin film (molecule accumulation film) formed by the LB method.

When the vapor deposition method cannot be applied,
As disclosed in JP-A-59-194393, etc., after dissolving a binder such as a resin and a distyrylarylene derivative of the general formula (I) in a solvent to form a solution, the solution is spin-coated or the like. The light-emitting layer can be formed by thinning. The thickness of the light-emitting layer formed using the distyrylarylene derivative is not particularly limited and may be appropriately set in practice, but is usually 5 nm to 5 μm.
Is set in the range.

(3) Recombination Site Forming Material It is preferable that at least one of the recombination region and the light emitting region of the organic EL device contains a recombination site forming material. Since the recombination region and the light-emitting region are usually light-emitting layers, it is desirable that the light-emitting layer contain a recombination site-forming substance. When layers other than the light emitting layer, the hole injection layer, the electron injection layer, the electron transport layer, the organic semiconductor layer, the electron barrier layer, the adhesion improving layer, and the like are involved in recombination and light emission, these layers are used. It is also preferable to contain a recombination site forming substance.

It is preferable that the recombination site-forming substance is contained at a ratio of 0.1 to 10% by weight with respect to each layer. That is, if the amount of the recombination site-forming substance is less than 0.1% by weight, the effect of the recombination site-forming substance may not be sufficiently exerted. If the amount exceeds 10% by weight, quenching may occur due to association between the recombination site-forming substances. In some cases, a sufficient effect cannot be obtained due to a phenomenon. The content of the recombination site-forming substance is preferably in the range of 0.3 to 4% by weight, more preferably 0.8 to 3% by weight, from the viewpoint of extending the life of the device and increasing the efficiency. is there. When the recombination site forming substance is a material that is difficult to quench the concentration, 10 to 90%
It may be used in a proportion of% by weight. As such a recombination site-forming substance, there is a polyarylenevinylene derivative in which an alkyl group having 6 or more carbon atoms or alkyloxy group substitution is introduced into a repeating unit.

The substance for forming a recombination site has a fluorescence yield of 0.5.
It is desirable that the material be at least one selected from fluorescent materials in the range of 3 to 1.0. Specifically, any one of a styrylamine compound, a quinacridone derivative, a rubrene derivative, a coumarin derivative, and a pyran derivative is used alone. Or two or more kinds can be used in combination. As the fluorescent material, a polyarylenevinylene derivative among conjugated polymers is preferable.
To 50 alkyl groups, alkoxy group-substituted polyarylene, and vinylene derivatives are preferred. Specific examples of the fluorescent material include compounds represented by the following formulas [51] to [61].

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

It is preferable that the fluorescent material is selected in consideration of the coloring properties of the light emitting layer and the like. For example, when a blue color is desired, it is preferable to use perylene (Pe) represented by the formula [53], an amino-substituted distyryl arylene derivative represented by the formula [51], and the like. Can be BCzVBi represented by the formula [52], DPAVBi represented by the formula [54], and the like. When a green color is desired, it is preferable to use a quinacridone derivative, a coumarin derivative of C540 represented by the above formula [55], and the like. As the quinacridone derivative, QN1 represented by the formula [56] and the above formula [55] 5
7] and the like. When a yellow color is desired, it is preferable to use a rubrene (Rb) derivative represented by the above formula [58]. Further, when an orange or red-orange color is desired, DCM1 represented by the formula [59] or D1 represented by the formula [60] is used.
It is preferable to use a dicyanomethylpyran derivative such as CM2.

The method for incorporating such a fluorescent material into the light-emitting layer or the like is not particularly limited. For example, co-evaporation in which a material (host material) constituting the organic compound layer such as the light-emitting layer and the fluorescent material are simultaneously deposited. It is preferable to adopt the method. In the co-evaporation method, separate evaporation sources (boats) each containing a host material and a fluorescent material are prepared, and heat evaporation is performed at the same time.

(4) Electrode It is preferable that the anode of the organic EL element is formed using an electrode material having a large work function (4 eV or more). As the electrode material, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like can be adopted. Specifically, a metal such as Au,
Conductive transparent materials such as InZnO, ITO, SnO ₂ , ZnO and the like can be mentioned. The anode can be manufactured by forming a thin film using such an electrode material by a method such as evaporation or sputtering. The thickness of the anode may be appropriately set according to the material, but is usually selected in the range of 10 nm to 1 μm, and preferably in the range of 10 to 200 nm. Further, the sheet resistance as an electrode is preferably several hundred Ω / □ or less.

The cathode has a small work function (4 eV or less).
It is preferable to use an electrode material. As the electrode material, metals, alloys, electrically conductive compounds, mixtures thereof, and the like can be employed. Specifically, sodium, sodium-potassium alloy, magnesium, lithium, magnesium: copper alloy, Al / Al ₂ O ₃ , Indium, Al:
Li alloy etc. are mentioned. The cathode can be formed by forming a thin film using such an electrode material by a method such as vapor deposition or sputtering. Further, the sheet resistance as an electrode is preferably several hundred Ω / □ or less, and the film thickness is usually
It is selected in the range of 10 nm to 1 μm, preferably 50
２００200 nm.

In the organic EL device, since the anode and the cathode are provided so as to sandwich the light-emitting layer, at least one of the anode and the cathode is transparent in order to extract light efficiently. Alternatively, it is preferably translucent. When light emission is extracted through the electrodes as described above, it is desirable that the transmittance be greater than 10%.

(5) Production of Organic EL Device A method for producing an organic EL device of the present invention will be described for an organic EL device having an anode / light-emitting layer / cathode element structure. First, a thin film made of a desired anode electrode material is formed on an appropriate substrate by a method such as vapor deposition or sputtering to form an anode. At this time, the anode is 10 nm-1.
The film is formed to have a thickness of μm, preferably 10 to 200 nm.

Thereafter, a thin film made of a distyrylarylene derivative represented by the general formula [I] as a light emitting material is laminated on the anode to form a light emitting layer. As a method of forming the light emitting layer, for example, a spin coating method, a casting method,
Although there is a vapor deposition method and the like, a vapor deposition method is preferable because a uniform film is easily obtained and a pinhole is hardly generated. When the vapor deposition method is adopted, the vapor deposition conditions may be set according to the type of the organic compound that is the constituent material of the light emitting layer, the target crystal structure or association structure of the molecular deposition film, and generally, the vapor deposition source (boat ) Heating temperature 50 ~ 400 ℃, degree of vacuum 10 ^-5 ~
It can be set appropriately within the range of 10 ⁻³ Pa, a deposition rate of 0.01 to 50 nm / sec, a substrate temperature of −50 ° C. to + 300 ° C., and a film thickness of 5 nm to 5 μm.

When the light-emitting layer contains a recombination site-forming substance, it is preferable to form the light-emitting layer by vapor-depositing the recombination site-forming substance on the anode simultaneously with the distyrylarylene derivative (co-evaporation method). .

After forming the light emitting layer, a thin film made of a cathode electrode material is formed on the light emitting layer by a method such as vapor deposition or sputtering to a thickness of 10 nm to 1 μm, preferably 50 to 200 nm. Then, a cathode is formed to obtain an organic EL element. In the production of this organic EL element, the production order of the film was reversed, and the cathode,
It is also possible to laminate the light emitting layer and the anode in this order.

When another organic compound layer such as a hole transporting layer is interposed between the light emitting layer and the electrode, similarly to the light emitting layer, for example, a spin coating method, a casting method, a vapor deposition method or the like is used. Each layer may be formed, and it is particularly preferable to use an evaporation method.

The organic EL of the present invention thus obtained
In the device, the anode has a positive polarity and the cathode has a negative polarity of 1 to 30 V.
When the DC voltage is applied, light emission can be observed from the transparent or translucent electrode side. Even if a voltage is applied with the polarity reversed, no current flows, and no light emission occurs. When an AC voltage is applied, the anode is + and the cathode is-
It emits light only when the state is reached. The AC waveform applied at this time is arbitrary.

[0069]

Next, the present invention will be described with reference to specific examples. Example 1 25 mm × 75 mm as a transparent support substrate
An ITO (indium tin oxide) electrode having a film thickness of 100 nm was prepared on a glass substrate having a size of × 1.1 mm.
After ultrasonic cleaning for 5 minutes, the substrate was washed with pure water for 5 minutes and again with isopropyl alcohol for 5 minutes. Next, the washed transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus (manufactured by Nippon Vacuum Engineering Co., Ltd.). In addition, two molybdenum resistance heating boats disposed in a vacuum chamber of a vacuum evaporation apparatus are each provided with a compound [1] as a luminescent material.
200 mg and 4,4'-bis [2- {4-
200 mg of (N, N-diphenylamino) phenyl @ vinyl] biphenyl (DPAVBi) were separately charged.

Next, the inside of the vacuum chamber is set to 1 × 10 ⁻⁴ Pa
After reducing the pressure, the two boats were simultaneously heated to evaporate the compound [1] and DPAVBi at the same time, and a 400 nm-thick mixed light emitting layer was deposited on the transparent support substrate.
The mixing ratio (weight ratio) in this mixed light emitting layer was compound [1]: DPAVBi = 40: 1.

Thereafter, the transparent support substrate was taken out of the vacuum chamber, a stainless steel mask was set in the vacuum chamber, and the taken-out substrate was again fixed to the substrate holder. In addition, molybdenum boats have Al: L
An i-alloy (Li; 5 atomic%) was charged, and the pressure in the vacuum chamber was reduced again to 1 × 10 ⁻⁴ Pa. Then, Al:
Li alloy is deposited at a deposition rate of 1.0 nm / sec.
l: Li alloy electrode prepared, ITO electrode / light emitting layer / A
1: An organic EL device comprising a Li alloy electrode was obtained.

The organic EL device obtained in this manner is provided with an IT
A light emission test was performed by applying a voltage of 8 V using the O electrode as an anode and the Al: Li alloy electrode as a cathode. As a result, uniform blue light emission was obtained. Table 1 shows the results. That is, the initial performance is such that the current density is 2.1 mA / cm at an applied voltage of 10 V.
² , the luminance was 100 cd / m ² , and the luminous efficiency was 1.5 lm / W. When this device was driven at a constant current of 100 cd / m ^{2 in a} nitrogen stream, the half-life at which the luminance became 50 cd / m ² was 1000 hours or more.

[0073]

[Table 1]

[Examples 2 to 9] In Example 1,
An organic EL device was prepared in the same manner as in Example 1 except that the materials shown in Table 1 were used as the light emitting material and the recombination site forming material constituting the light emitting layer, and a light emission test was performed. Table 1 shows the results.

Example 10 In Example 1, the compound [18] was used as the luminescent material, and the polyphenylene derivative (BuEH-PPV) represented by the formula [61] was used as the recombination site-forming substance. An organic EL device was obtained in the same manner as in Example 1 except that the light emitting layer was formed by spin coating. That is, compound [18] which is a light emitting material and B which is a recombination site forming substance
uEH-PPV was accommodated in a container and uniformly dissolved using toluene to obtain a coating solution. In addition, BuEH-PPV
Was 60% by weight of the coating solution. Then, the washed IT
The coating liquid was applied on a transparent substrate with O using a spin coater, and then heated and dried to form a light emitting layer having a thickness of 95 nm. A cathode was formed on the light emitting layer in the same manner as in Example 1, and an organic EL device of Example 10 was manufactured. A light emission test was performed in the same manner as in Example 1. Table 1 shows the results.

From Table 1, it can be seen that by forming an organic EL device using the distyrylarylene derivative of the present invention represented by the general formula [I], excellent luminous efficiency was obtained even with a single-layer structure having only a luminescent layer. It can be seen that the driving at a low voltage can be realized.

Example 11 In Example 11, the distyrylarylene derivative of the present invention was used as a hole transporting material, and the ITO electrode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / Al : An experiment for producing an organic EL device comprising a Li alloy electrode. That is, an organic EL device was obtained in the same manner as in Example 1 except that a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer were formed as follows. .

That is, 4,4 ′ as a hole injection material
-Bis- (N, N-di- (3-tolyl) amino)-
4 "-phenyl-triphenylamine (TAPTP
A) 500 mg of a compound [1] as a hole transport material
200 mg and 4,4'-bis (2,2
2-diphenylvinyl) biphenyl (DPVBi) 20
0 mg and 4,4'-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] biphenyl (DPAVB) represented by the formula [54] as a recombination site-forming substance
i) 200 mg of tris (8-
(Hydroxyquinoline) aluminum (AlQ) 100m
g were placed separately in five molybdenum resistance heating boats.

Then, the inside of the vacuum chamber is set to 1 × 10 ⁻⁴ Pa
After reducing the pressure, the boat containing TAPPTA was heated to evaporate TAPPTPA, and a 60-nm-thick hole injection layer was laminated on the ITO film on the transparent substrate. Next, the boat containing the compound [1] was heated to deposit the compound [1] on the hole injection layer, thereby forming a hole transport layer having a thickness of 40 nm. Subsequently, the DPVBi-containing boat and the DPAVBi-containing boat are simultaneously heated and evaporated, and the DPVBi and DPAVBi film thickness 40n is formed on the hole transport layer.
m mixed light emitting layer (DPVBi: DPAVBi = 40: 1)
Weight ratio). Thereafter, the boat containing ALQ was heated and evaporated, and a 20-nm-thick electron injection layer was formed on the mixed light emitting layer.

The transparent substrate on which each layer was formed in this manner was taken out of the vacuum chamber, and an Al: Li alloy electrode was formed on the electron injection layer in the same manner as in Example 1 to obtain the organic substrate of Example 11. An EL device was obtained.

When a voltage of 8 V was applied to the obtained organic EL device using the ITO electrode as the anode and the Al: Li alloy electrode as the cathode, a light emission test was carried out. As a result, uniform blue light emission was obtained. Table 2 shows the results. That is, the initial performance is
At an applied voltage of 7.5 V, the current density was 1.8 mA / cm ² , the luminance was 100 cd / m ² , and the luminous efficiency was 2.3 lm / W.
When this element was driven with a constant current in a nitrogen stream at an initial luminance 100 cd / m ^2, the half-life in which the luminance becomes 50 cd / m ² was more than 2000 hours.

[0082]

[Table 2]

[Examples 12 and 13] An organic EL device was manufactured in the same manner as in Example 11 except that the materials shown in Table 2 were used as the hole transporting material, and a light emission test was performed. went. Table 2 shows the results.

Table 2 shows that the distyryl arylene derivative of the present invention represented by the general formula [I] has an excellent hole transporting function and can be effectively used as a hole transporting material.

[0085]

As described above, according to the present invention,
By constituting an organic EL element using the distyrylarylene derivative represented by the general formula [I], excellent luminous efficiency can be obtained and driving at a low voltage can be realized. Therefore, since excellent performance can be obtained even with a single layer, the element configuration can be simplified. Further, the distyrylarylene derivative represented by the general formula [I] can be used not only as a light emitting material of an organic EL device but also as a hole transport material.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/14 H05B 33/14 B 33/22 33/22 DF Term (Reference) 3K007 AB03 AB04 AB06 CA01 CB01 DA00 DB03 EB00 FA01 FA03 4H006 AA01 AA03 AB78 AB91 AB92 GP03 GP06

Claims (7)

[Claims] 1. A compound of the general formula [I] (Wherein, An represents a divalent group consisting of a substituted or unsubstituted fused ring containing at least three rings. Ar ₁ and Ar ₂ each independently represent a single bond, 6 to 30 carbon atoms.
And polyarylene which is an aggregate of arylene. R _{1 to} R ₄ each independently represent hydrogen, substituted or unsubstituted C 6 to C 3,
0 represents an aryl group or a polyaryl group that is an aggregate of aryl groups. R _{1 to} R ₄ are
It is at least three-substituted, substituted with R ₁ and R ₂ , or substituted with R ₃ and R ₄ by an amino group or an oxy substituent. Here, the substituent means an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an aryl group having 6 to 20 carbon atoms, an amino group, a cyano group. , A nitro group, a hydroxyl group or a halogen atom. These substituents may be single or plurally substituted. A distyryl arylene derivative represented by). 2. An organic electroluminescent device, comprising: the distyrylarylene derivative according to claim 1; and a pair of electrodes sandwiching the distyrylarylene derivative. 3. The organic electroluminescence device according to claim 2, wherein the distyryl arylene derivative is used as a constituent material of a light emitting layer. 4. The organic electroluminescence device according to claim 3, wherein the light emitting layer contains a recombination site forming substance. 5. The organic electroluminescence device according to claim 4, wherein the recombination site forming substance is made of at least one selected from fluorescent materials having a fluorescence yield in a range of 0.3 to 1.0. An organic electroluminescence device characterized by the following. 6. The organic electroluminescence device according to claim 5, wherein the fluorescent material is a styrylamine-based compound, a quinacridone derivative, a rubrene derivative, a coumarin derivative, or a pyran derivative. 7. The organic electroluminescence device according to claim 2, wherein the distyryl arylene derivative is used as a constituent material of a hole transport layer.