JPH06100857A - Organic electroluminescent element - Google Patents

Abstract

PURPOSE:To obtain the subject element excellent in film thinness and capable of high-luminance emission by incorporating a diolefin compound of a specified formula. CONSTITUTION:This organic electroluminescent element(EL element) is obtained by using a diolefin compound of formula I [wherein Ar<1> and Ar<2> are each (substituted)6-20 C aryl; Ar<2> is (substituted)6-20 C arylene; R<2> is H, (substituted)6-20 C aryl or 1-6 C alkyl; and R<1> and R<2> may be combined with each other to form a (substituted)saturated five-or six-membered ring, and the substituents include 1-6 C alkyl, 1-6 C alkoxyl, 6-18 C aryloxyl, phenyl, NH2, CN, NO2 and halogen, provided that each of the above groups may have one or more of these substituents] (e.g. a compound of formula II). This EL element is excellent in film thinness and capable of high-luminance emission, so that it can be used in various industrial fields.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence device (organic EL device), and more particularly, to an organic EL device composed of a diolefin compound which has excellent thin film properties and enables high-luminance light emission.

[0002]

2. Description of the Related Art EL devices utilizing electroluminescence have the characteristics that they are self-luminous and therefore highly visible, and because they are completely solid-state devices, they are excellent in impact resistance. It is used for thin display devices, liquid crystal display backlights, flat light sources, and so on. The EL element currently put into practical use is a dispersion type EL element. This dispersion type EL device has several tens of volts and 10 kHz.
Since the above AC voltage is required, the drive circuit is complicated. On the other hand, since the organic thin film EL element can reduce the driving voltage to about 10 V and emits light with high brightness, research has been actively conducted in recent years, and many organic thin film EL elements have been developed (CWTang and SAVAN Slyke, Appl.Phys.L
ett., vol.51, pp.913-915 (1987); JP-A-63-264.
629 publication). These organic thin film EL devices are a laminated type of transparent electrode / hole injection layer / light emitting layer / back electrode, and holes can be efficiently injected into the light emitting layer by the hole injection layer. In the structure of the organic thin film EL device, there is an organic EL thin film device using a tetraphenylbutadiene compound derivative in the light emitting layer (Japanese Patent Laid-Open Nos. 59-194393 and 4-96990). However, even if they have a low applied voltage and emit light with high brightness, there is a problem in manufacturing the device because the luminescent material crystallizes quickly and has a short life. Further, a styryl compound is generally used in the light emitting layer (European Patent Publication No. 0388768),
It has been clarified that a uniform amorphous thin film is easily formed on these.

[0003]

Therefore, the present inventors have
As a result of extensive studies to solve the above problems, a diolefin compound obtained by molecularly designing a compound having both the characteristics of a tetraphenylbutadiene compound derivative and a styryl compound was used for an organic EL device, and thus a thin film property was obtained. It was found that an excellent EL device can be provided.

The present invention has been completed based on such findings. That is, the present invention has the general formula (I)

[0005]

[Chemical 2]

(In the formula, Ar ¹ and R ¹ each represent a substituted or unsubstituted aryl group having 6 to 20 carbon atoms,
Ar ² represents a substituted or unsubstituted arylene group having 6 to 20 carbon atoms. R ² represents a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. Here, even if R ¹ and R ² are the same,
Further, they may be different from each other, and may be bonded to a substituted group to form a substituted or unsubstituted saturated five-membered ring or a substituted or unsubstituted saturated six-membered ring. Here, as the substituent, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, a phenyl group, an amino group, a cyano group, a nitro group, a hydroxyl group or halogen. Indicates. These substituents may be single or multiple. The organic electroluminescent element containing the diolefin compound represented by these is provided.

The present invention is an organic EL device containing a diolefin compound represented by the general formula (I). here,
In the general formula (I), Ar ¹ and R ¹ are, for example, phenyl group, naphthyl group, biphenyl group, terphenyl group, anthrylyl group, phenanthryl group, pyrenyl group,
It is an aryl group having 6 to 20 carbon atoms represented by a perenyl group and the like. These aryl groups may be substituted or unsubstituted, and may be mono-substituted or plural-substituted. Also,
Ar ² is, for example, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms represented by a phenylene group, a naphthylene group, a biphenylene group, a terphenylene group, an anthracenediyl group, a pyrenediyl group and the like. These arylene groups may be substituted or unsubstituted, and may be mono-substituted or plural-substituted. R ² is a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms (for example, phenyl group, naphthyl group, biphenyl group, terphenyl group, anthryl group, phenanthryl group, pyrenyl group, perylenyl group, etc.), An alkyl group having 1 to 6 carbon atoms (eg, methyl group, ethyl group, n-propyl group, i-
Propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, i-pentyl group, t-pentyl group, neopentyl group, n-hexyl group, i-hexyl group and the like). . Here, as the substituent, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group,
n-butyl group, i-butyl group, sec-butyl group, t-
Butyl group, i-pentyl group, t-pentyl group, neopentyl group, n-hexyl group, i-hexyl group and other alkyl groups having 1 to 6 carbon atoms, methoxy group, ethoxy group, propoxy group, i-propoxy group, Carbon number such as butyloxy group, i-butyloxy group, sec-butyloxy group, i-pentyloxy group, t-pentyloxy group, n-hexyloxy group and the like, phenoxy group, naphthyloxy group, etc. And 6 to 18 aryloxy groups, phenyl groups, amino groups, cyano groups, nitro groups, hydroxyl groups or halogens. Also, R ¹ and R
^{The two} may be the same or different from each other, and may combine with a substituting group to form a substituted or unsubstituted saturated five-membered ring or a substituted or unsubstituted saturated six-membered ring.

The diolefin compound represented by the above general formula (I) can be produced by various known methods. Specifically, this diolefin compound can be easily produced from the following documents. NPBuu-Hoi, TBLoo, and NDXuong, J.Chem.Soc., 3964
(1957) Bertoniere, Rowland, and Griffin, J.Org.Chem.Vol 36, N
o.20,294 (1971) Z.Yang, HJ Geise, Synthetic Metals, 47 (1992) 111-132 H.-H.Hoerhold, M.Helbig, Materials Science Forum Vol
ts.62-64 (1990), pp.411-417 Specific examples (1) to (29) of the diolefin compound used in the present invention are shown below, but the present invention is not limited thereto. Absent.

[0009]

[Chemical 3]

[0010]

[Chemical 4]

[0011]

[Chemical 5]

[0012]

[Chemical 6]

[0013]

[Chemical 7]

[0014]

[Chemical 8]

The diolefin compound represented by the general formula (I) of the present invention thus obtained is effective as a light emitting material in an EL device. When the diolefin compound is used as the light emitting layer, it can be formed by thinning the diolefin compound of the general formula (I) by a known method such as a vapor deposition method, a spin coating method, or a casting method. It is particularly preferable to use a molecular deposition film. Here, the molecular deposition film is a thin film formed by depositing the compound from a gas phase state, or a film formed by solidifying from a solution state or a liquid phase state of the compound, for example, a vapor deposition film or the like. Although shown, this molecular deposition film can be generally distinguished from a thin film (molecular cumulative film) formed by the LB method. Further, the light emitting layer is disclosed in JP-A-59-19439.
As disclosed in Japanese Patent No. 3 or the like, a binder such as a resin and the compound are dissolved in a solvent to form a solution, which can be formed into a thin film by a spin coating method or the like. The thickness of the light emitting layer thus formed is not particularly limited and may be appropriately selected depending on the circumstances, but is usually selected in the range of 5 nm to 5 μm.

The light emitting layer in this EL element is (1) injection in which holes can be injected by the anode or the hole injection transport layer and electrons can be injected by the cathode or electron injection layer when an electric field is applied. Function, (2) transport function to move the injected charges (electrons and holes) by the force of the electric field, (3) provide a field for recombination of electrons and holes inside the light emitting layer, and connect this to light emission It has functions. It should be noted that there may be a difference between the ease with which holes are injected and the ease with which electrons are injected, and the transport capacity represented by the mobility of holes and electrons may be large or small. It is preferable to transfer the electric charges of. The compound represented by the general formula (I) used for the light emitting layer generally has an ionization energy of 6.0e.
Since it is smaller than about V, holes can be relatively easily injected by selecting an appropriate anode metal or anode compound. Further, since the electron affinity is larger than about 2.8 eV, if an appropriate cathode metal or cathode compound is selected, it is relatively easy to inject electrons and the electron and hole transporting ability is excellent. Furthermore, since the solid-state fluorescence is strong, it has a large ability to convert the excited state formed at the time of recrystallization of electrons and holes of the compound or its associated body or crystal into light.

The EL device using the compound of the present invention may have various constitutions. Basically, the light emitting layer is sandwiched between a pair of electrodes (anode and cathode). A hole injecting and transporting layer and an electron injecting layer may be interposed if necessary. The intervening method includes mixing into the polymer and simultaneous adhesion. Specifically, (1) anode / light emitting layer / cathode, (2) anode / hole injection layer (hole injection / transport layer) / light emitting layer / cathode, (3) anode / hole injection layer (hole injection / transport). layer)
Examples of the structure include / light emitting layer / electron injection layer / cathode and (4) anode / light emitting layer / electron injection layer / cathode. The hole injecting layer (hole injecting and transporting layer) and the electron injecting layer are not always necessary, but the presence of these layers further improves the light emitting performance. Further, it is preferable that all of the elements having the above-mentioned constitution are supported by a substrate, and there is no particular limitation on the substrate, and the elements conventionally used for EL elements such as glass, transparent plastic, quartz and the like are used. Any thing can be used.

As the anode in this EL element, a material having a high work function (4 eV or more), metal, alloy, electrically conductive compound or a mixture thereof as an electrode material is preferably used. Specific examples of such an electrode material include A
Examples thereof include metals such as u and dielectric transparent materials such as CuI, ITO, SnO ₂ , and ZnO. The anode can be prepared by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. When the emitted light is taken out from this electrode, it is desirable that the transmittance is higher than 10%, and the sheet resistance as an electrode is preferably several hundred Ω / □ or less. The film thickness depends on the material, but is usually 10 nm to 1 μm, preferably 10 nm to 1 μm.
It is selected in the range of 200 nm.

On the other hand, as the cathode, a material having a low work function (4 eV or less), an alloy, an electrically conductive compound or a mixture thereof as an electrode material is used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, Al / AlO ₂ , indium and the like. The cathode can be produced by forming a thin film of these electrode substances 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 10 nm.
To 1 μm, preferably 50 to 200 nm. In this EL element, it is convenient that either the anode or the cathode is transparent or semi-transparent to allow the emitted light to pass therethrough, so that the emission efficiency of the emitted light is good.

The EL device using the compound of the present invention has various configurations as described above, and the hole injecting layer (hole injecting and transporting layer) in the EL device of the above (2) or (3) is used. ) Is a layer composed of a hole transfer compound, and has a function of transferring holes injected from the anode to the light emitting layer,
By interposing this hole injecting and transporting layer between the anode and the light emitting layer, many holes are injected into the light emitting layer with a lower electric field. In addition, the electrons injected from the cathode or the electron injection layer into the light emitting layer are accumulated near the interface in the light emitting layer due to the electron barrier existing at the interface between the light emitting layer and the hole injecting and transporting layer, and the EL element emits light. E with improved efficiency and excellent light emission performance
Let it be an L element.

The hole transport compound used in the hole injecting and transporting layer is disposed between two electrodes to which an electric field is applied, and when holes are injected from the anode, the holes are appropriately emitted. A compound which can be transmitted to, for example, 10 ⁴ to 10 ⁶ V
At least 10 ^-6 cm ² / (V
A hole mobility of (sec) is preferable. The hole transporting compound is not particularly limited as long as it has the above-mentioned preferable properties, and is conventionally used as a charge transporting material for holes in photoconductive materials and the hole of EL elements. Any known material can be selected and used from the known materials used for the injecting and transporting layer.

Examples of the charge transport material include triazole derivatives (described in US Pat. No. 3,112,197), oxadiazole derivatives (US Pat. No. 3,1).
89,447, etc.), imidazole derivatives (described in Japanese Patent Publication No. 37-16096, etc.), polyarylalkane derivatives (US Pat. No. 3,61).
5,402, 3,820,989, 3,5
42,544, Japanese Patent Publication No. 45-555, 5
1-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55-108667, and JP-A-55-15695.
No. 3, JP-A-56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. Nos. 3,180,729, 4,278,746 and JP-A-55-55). No. 88064, 55-8806.
5 gazette, the same 49-105537 gazette, the same 55-51.
086, 56-80051, 56-8
No. 8141, No. 57-45545, No. 54-
No. 112637, No. 55-74546, etc.), phenylenediamine derivatives (U.S. Pat. No. 3,615,044, Japanese Patent Publication Nos. 51-10105, 46-3712, 47). No. 25336, JP-A No. 54-53435, and No. 54-1105.
No. 36, No. 54-119925, etc.), arylamine derivatives (US Pat. No. 3,567,4).
No. 50, No. 3,180,703, No. 3,24
No. 0,597, No. 3,658,520, No. 4,2
32,103, 4,175,961, 4,012,376, JP-B-49-35702, 39-27577, and JP-A-55-1442.
No. 50, No. 56-119132, No. 56-2
2437 gazette, those described in West German Patent No. 1,110,518 etc.), amino-substituted chalcone derivatives (described in US Pat. No. 3,526,501 etc.), oxazole derivatives (US patent Nos. 3,257,203), styrylanthracene derivatives (described in JP-A-56-46234), fluorenone derivatives (described in JP-A-54-110837). ), Hydrazone derivatives (US Pat. No. 3,71
7,462, JP-A-54-59143, JP-A-55-52063, JP-A-55-52064,
55-46760, 55-85495, 57-11350 and 57-148749.
Those described in JP-A-62-110363 and JP-A-61-2284.
No. 51, No. 61-14642, No. 61-72.
255, 62-47646, 62-3.
6674, 62-10652, and 62-
No. 30255, No. 60-93445, No. 60
-94462, 60-174749, 60-175052, etc.) and the like.

These compounds can be used as a hole transfer compound, and the porphyrin compounds shown below (those described in JP-A-63-295695)
And aromatic tertiary amine compounds and styrylamine compounds (U.S. Pat. No. 4,127,412, JP-A-53-53)
27033, 54-58445, 54.
No. 149634, No. 54-64299, No. 55-79450, No. 55-144250, No. 56-119132, No. 61-29555.
8 gazette, the same 61-98353 gazette, the same 63-295.
No. 695, etc.), and it is particularly preferable to use the aromatic tertiary amine compound.

Representative examples of the porphyrin compound include:
Porphyrin; 5,10,15,20-tetraphenyl-21H, 23H-porphyrin copper (II); 5,10,
15,20-Tetraphenyl-21H, 23H-porphyrin zinc (II); 5,10,15,20-Tetrakis (pentafluorophenyl) -21H, 23H-porphyrin; Silicon phthalocyanine oxide; Aluminum phthalocyanine chloride; Phthalocyanine (metal free) ); Dilithium phthalocyanine; copper tetramethyl phthalocyanine; copper phthalocyanine; chromium phthalocyanine; zinc phthalocyanine; lead phthalocyanine; titanium phthalocyanine oxide; magnesium phthalocyanine; copper octamethyl phthalocyanine.
Further, as typical examples of the aromatic tertiary compound and the styrylamine compound, N, N, N ′, N′-tetraphenyl- (1,1′-biphenyl) -4,4′-diamine;
N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1'-biphenyl] -4,4'-diamine; 2,2-bis (4-di-p-tolylamino) Phenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-tetra-p-tolyl- (1,1'-biphenyl) -4,
4'-diamine; 1,1-bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p- Tolylaminophenyl) phenylmethane; N, N′-diphenyl-N, N′-di (4-methoxyphenyl)-(1,1′-biphenyl)
-4,4'-diamine; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,
4'-bis (diphenylamino) quadriphenyl;
N, N, N-tri (p-tolyl) amine; 4- (di-p
-Tolylamine) -4 '-[4 (di-p-tolylamine) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylamino Stilbene; N-
Examples include phenylcarbazole.

The hole injecting and transporting layer in the EL device may be composed of a single layer composed of one or more of these hole transporting compounds, or a hole composed of a compound different from the layer. It may be a stack of injecting and transporting layers. On the other hand, the electron injecting layer (electron injecting and transporting layer) in the EL device having the above-mentioned configuration (3) is made of an electron transfer compound and has a function of transferring the electrons injected from the cathode to the light emitting layer. There is. There is no particular limitation on such an electron transfer compound, and any compound can be selected and used from conventionally known compounds. Preferred examples of the electron transfer compound include:

[0026]

[Chemical 9]

Nitro-substituted fluorenone derivatives such as

[0028]

[Chemical 10]

Thiopyran dioxide derivatives such as

[0030]

[Chemical 11]

Diphenylquinone derivatives such as those described in "Polymer Preprints, Japan", Volume 37, No. 3, page 681 (1988), or the like.

[0032]

[Chemical 12]

Compounds such as [Journal of Applied Physics, Vol. 27,
Those described on page 269 (1988), etc., and anthraquinodimethane derivatives (JP-A-57-149259, JP-A-58-55450, JP-A-61-22515).
No. 1, gazette 61-233750, gazette 63-10.
4061) and fluorenylidene methane derivatives (JP-A-60-69657 and 61).
Those described in JP-A-143764, JP-A-61-148159, etc.) and anthrone derivatives (JP-A-61-2).
No. 25151, No. 61-233750, etc.) Further, the following general formula (II) or (III)

[0034]

[Chemical 13]

(In the formula, Ar ^{3 to} Ar ⁵ and Ar ⁷ each independently represent a substituted or unsubstituted aryl group, and Ar ⁶
Represents a substituted or unsubstituted arylene group. ) And an electron transfer compound represented by. Here, examples of the aryl group include a phenyl group, naphthyl group, biphenyl group, anthranyl group, perylenyl group, and pyrenyl group, and examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthracenylene group, a perylenylene group, and a pyrenylene group. Etc. Moreover, as a substituent, a C1-C10 alkyl group, a C1-C10 alkoxy group, a cyano group, etc. are mentioned. The compound represented by the general formula (II) or (III) is preferably one capable of forming a thin film. Specific examples of the compound represented by the general formula (II) or (III) include:

[0036]

[Chemical 14]

[0037]

[Chemical 15]

[0038]

[Chemical 16]

And the like.

"Appl. Phys. Lett." Volume 55, 148
Oxadiazole derivatives disclosed on page 9 (1989) can be mentioned. Note that the hole injecting and transporting layer and the electron injecting layer are layers having any of an injecting property, a transporting property, and a barrier property for electrification, and in addition to the above-mentioned organic materials, crystallinity of Si-based, SiC-based, CdS-based, etc. It is also possible to use an inorganic material such as an amorphous material. The hole injecting and transporting layer and the electron injecting layer using the organic material can be formed in the same manner as the light emitting layer, and the hole injecting and transporting layer and the electron injecting layer using the inorganic material are formed by the vacuum deposition method or the sputtering. However, it is preferable to use the vacuum vapor deposition method for the same reason as in the case of the light emitting layer regardless of whether organic or inorganic materials are used.

Next, an example of a suitable method for producing an EL device using the compound of the present invention will be described for each device having each constitution. EL consisting of the above-mentioned anode / light-emitting layer / cathode
Explaining the method of manufacturing the device, first, a thin film made of a desired electrode material, for example, a material for an anode, is vapor-deposited or sputtered on a suitable substrate so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. After forming a positive electrode by a method such as the above, a thin film of a diolefin compound represented by the general formula (I), which is a light emitting material, is formed thereon, and a light emitting layer is provided. As a method for thinning the light emitting material, there are, for example, a spin coating method, a casting method, a vapor deposition method and the like, but the vapor deposition method is preferable from the viewpoint that a uniform film is easily obtained and pinholes are not easily generated. . When this vapor deposition method is used for thinning the light emitting material, the vapor deposition conditions generally differ depending on the type of organic compound used in the light emitting layer used, the target crystal structure of the molecular deposited film, the association structure, etc. Boat heating temperature 50-40
0 ° C., vacuum degree 10 ⁻⁵ to 10 ⁻³ Pa, vapor deposition rate 0.01 to 5
0 nm / sec, substrate temperature −50 to + 300 ° C., film thickness 5
It is desirable to appropriately select in the range of nm to 5 μm. Next, after forming this light emitting layer, a thin film made of a substance for the cathode is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 50 to 200 nm. By providing, a desired EL element can be obtained. In the production of this EL element, it is possible to reverse the production order and produce the cathode, the light emitting layer and the anode in this order.

A hole injecting and transporting material is provided between the pair of electrodes,
In the case of an element composed of an anode / a light emitting layer / a cathode, which is sandwiched between electrodes in a form of a mixture of a light emitting material and an electron injecting material, a manufacturing method is, for example, a suitable substrate and an anode material. A thin film made of, and applied with a solution containing a hole injecting and transporting material, a light emitting material, an electron injecting material, a binder such as polyvinylcarbazole, or a thin film is formed from this solution by a dip coating method to form a light emitting layer. And a thin film made of a cathode material is formed thereon. Here, an element material which is a material of the light emitting layer may be further vacuum-deposited on the produced light emitting layer, and a thin film made of a substance for a cathode may be formed thereon. Alternatively, a hole injecting and transporting material, an electron injecting material and a light emitting material are simultaneously vapor deposited to form a light emitting layer,
You may form a thin film which consists of materials for cathodes on it.

Next, a method of manufacturing an EL element composed of anode / hole injecting / transporting layer / light emitting layer / cathode will be described. First, an anode is formed in the same manner as in the case of the EL element, and then it is formed thereon. A thin film made of a hole transfer compound is formed by a spin coating method or the like to provide a hole injection layer. The conditions at this time may be the same as the conditions for forming the thin film of the light emitting material. Next, a desired EL element is obtained by sequentially providing a light emitting layer and a cathode on the hole injecting and transporting layer in the same manner as in the case of manufacturing the EL element. Also in the fabrication of this EL element, it is possible to reverse the fabrication order and fabricate the cathode, the light emitting layer, the hole injecting and transporting layer, and the anode in this order. Further, a method of manufacturing an EL element composed of anode / hole injecting / transporting layer / light emitting layer / electron injecting layer / cathode will be described. First, in the same manner as in the case of manufacturing the EL element, an anode and a hole injecting / transporting layer are formed. After sequentially providing a layer and a light emitting layer, a thin film made of an electron transfer compound is formed on the light emitting layer by a spin coating method or the like to provide an electron injection layer, and then a cathode is provided on the light emitting layer of the EL device. A desired EL element can be obtained by providing the EL element in the same manner as in the case of manufacturing. Also in the production of this EL element, the order of production may be reversed, and the anode, the electron injection layer, the light emitting layer, the hole injection transport layer, and the anode may be produced in this order.

The organic EL of the present invention thus obtained
When a DC voltage is applied to the device, a voltage of about 1 to 30 V is applied with the positive polarity of the anode and the negative polarity of the cathode, and light emission can be observed from the transparent or semitransparent electrode side. Moreover, even if a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the − state. In addition,
The waveform of the alternating current applied may be arbitrary.

[0045]

EXAMPLES The present invention will be described in more detail with reference to synthesis examples and examples. Synthesis example 1

[0046]

[Chemical 17]

5.0 g of diphenylchloromethane (0.025
50 ml of a tetrahydrofuran solution of (mol) in an argon gas atmosphere at 0 ° C. with magnesium 1.0 g (.
(041 mol) over 1 hour. At this time, the reaction product became a yellow suspension. After stirring for 2 hours as it is,
50 ml of a tetrahydrofuran solution containing 3.0 g (0.01 mol) of 1,4-dibenzoylbenzene was stirred at 0 ° C. for 3 days.
It was added dropwise over 0 minutes. After further stirring for 4 hours, the reaction product became a yellowish green suspension. The obtained reaction product was put into 50 g of ice, extracted with 50 ml of methylene chloride, and the solvent was distilled off to obtain a pale yellow powder. The light yellow powder and 12 ml of formic acid were refluxed and stirred at 130 ° C. for 10 minutes, allowed to cool, and then poured into 50 g of ice to give 50 methylene chloride.
As a result of extraction with milliliter and purification with a silica gel column, 1.0 g of a yellow powder was obtained. I of the obtained yellow powder
As a result of R measurement, ν _{C = C} = 1598, 1500 cm ^-1 . As a result of mass spectrometry, it was m / Z = 586 (M ⁺ ). Further Elemental analysis (() calculated value), as _{C 46 H 34 C: 94.23%} (94.16%) H: was 5.77% (5.84%). In addition, proton nuclear magnetic resonance ( ¹ H-NMR,
Standard: tetramethylsilane (TMS), solvent: CDCl
₃ ) As a result of the measurement, δ was 7.0 to 7.5 ppm (m, 34H, aromatic ring H). From the above, the target diolefin compound (1)
It was confirmed that was synthesized.

Synthesis Example 2 A diolefin compound (1 was prepared in the same manner as in Synthesis Example 1 except that benzyl bromide was used instead of diphenylchloromethane.
4) was obtained. The physical properties of the obtained compound are shown in Table 1.

Synthesis Example 3 A diolefin compound (12) was obtained in the same manner as in Synthesis Example 1 except that α-bromoethylbenzene was used instead of diphenylchloromethane. The physical properties of the obtained compound are shown in Table 1.

Synthesis Example 4 A diolefin compound (9) was obtained in the same manner as in Synthesis Example 1 except that 1,4-dibenzoylbenzene was replaced with 4,4'-dibenzoylbiphenyl. The physical properties of the obtained compound are shown in Table 1.

[0051]

[Table 1]

Example 1 A glass substrate having a thickness of 100 nm (25 mm × 75 mm × 1.1 m)
m, made by HOYA) was used as the transparent support substrate. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol for 5 minutes, immersed in isopropyl alcohol for cleaning, and further cleaned with a UV ion cleaner (manufactured by Samco International). This transparent support substrate was dried with dry nitrogen gas, fixed on a substrate holder of a commercially available vapor deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.), and placed on a resistance heating boat made of molybdenum to produce N, N'-bis (3-methylphenyl). ) -N, N'-diphenyl-
[1,1'-biphenyl] -4,4'-diamine (TP
D) (200 mg) was added, and 1,4-bis (1,2-diphenylvinyl) benzene represented by the compound (1) obtained in Synthesis Example 1 was added to another molybdenum boat (200 mg).
Put it in another molybden boat, and then add the 2- (4-
Biphenylyl) -5- (4-t-butylphenyl)-
2,3,4-oxadiazole (t-BuPBD)
00 mg was put and it attached to the vacuum evaporation system. Then, the vacuum layer was depressurized to 4 × 10 ⁻⁶ Pa, and then the heating boat containing TPD was energized to heat it to 250 ° C.
The film thickness is 5 by vapor deposition on a transparent supporting substrate at 0.1 to 0.3 nm / sec.
A 0 nm hole injection transport layer was provided. Then, the heating boat containing 1,4-bis (1,2-diphenylvinyl) benzene was energized to heat up to 220 ° C., and the vapor deposition rate was 0.1.
A light emitting layer having a film thickness of 60 nm was provided by vapor deposition on the hole injecting and transporting layer at 1 to 0.3 nm / sec. Furthermore, t-BuPB
The heating boat containing D was energized and heated to 160 ° C., and vapor-deposited on the light emitting layer at a vapor deposition rate of 0.1 to 0.4 nm / sec to form an electron injection layer having a film thickness of 20 nm. The substrate temperature during vapor deposition was room temperature. Next, the vacuum chamber was opened, a mask made of stainless steel was placed on the electron injection layer, while 3 g of magnesium was placed in a resistance heating boat made of molybdenum, and indium was placed in another resistance heating filament, and the vacuum chamber was again set. Was reduced to 2 × 10 ⁻⁶ Pa, and a boat containing magnesium was energized to deposit magnesium at a deposition rate of 4 to 7 nm / sec. At the same time, indium was heated and vapor-deposited at a vapor deposition rate of 0.2 to 0.3 nm / sec to form a counter electrode made of the mixture of magnesium and indium, and an intended EL device was produced. A DC voltage of 10 V was applied using the ITO electrode of this device as an anode and the counter electrode made of a mixture of magnesium and indium as a cathode. When a current density of 35 milliamperes / cm ² was applied, blue green light with a peak wavelength of 488 nm was emitted. Got The brightness at this time was 250 cd / m ² .

Examples 2 to 4 Devices were prepared in the same manner as in Example 1 except that the compounds used in Example 1 were replaced with the compounds obtained in Synthesis Examples 2 to 4.
The results obtained are shown in Table 2.

[0054]

[Table 2]

Further, as a comparative example, the organic EL devices obtained in Examples 1 to 4 and an unsubstituted tetraphenylbutadiene compound (1,1,4,4-tetraphenyl-1,3-butadiene) were used as a light emitting layer. An optical microscope observation was performed to confirm the difference in the thin film property from the organic EL device used. The organic EL device used here was manufactured in the same manner as in Example 1.
As a result, the organic EL devices of Examples 1 to 4 were slowly crystallized, and no crystallization was observed for one month. On the other hand, the tetraphenylbutadiene compound used as the light emitting layer in the comparative example was crystallized within a few days after the device was formed. Therefore, it was confirmed that the thin film property of the present invention was excellent.

[0056]

As described above, the EL device using the diolefin compound of the present invention has excellent thin film properties and enables high-luminance light emission. Therefore, the present invention provides an organic EL device,
It can be used in various industrial fields.

Claims (3)

[Claims] 1. A compound represented by the general formula (I): (Wherein, Ar ¹ and R ¹ each represent a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, Ar ² represents a substituted or unsubstituted arylene group having 6 to 20 carbon atoms. Also, R ² Represents a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, wherein R ¹ and R ² may be the same or different from each other, May form a substituted or unsubstituted saturated five-membered ring or a substituted or unsubstituted saturated six-membered ring, wherein the substituent is an alkyl group having 1 to 6 carbon atoms, An alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, a phenyl group,
Indicates an amino group, cyano group, nitro group, hydroxyl group or halogen. These substituents may be single or multiple. ) An organic electroluminescence device containing a diolefin compound represented by the formula (1). 2. The diolefin compound according to claim 1,
An organic electroluminescence device sandwiched between a pair of electrodes. 3. An organic electroluminescence device, wherein the light emitting layer comprises the diolefin compound according to claim 1.