JPH0688072A - Organic electroluminescent element - Google Patents

Abstract

PURPOSE:To improve the thinness of films and adhesion to a cathode by sandwiching an electroluminescent element made up of a specific org. compd. between an anode and a cathode. CONSTITUTION:An electroluminescent element made up of at least one layer of a heterocyclic styryl compd. of the formula [wherein A is C or N; R<1> and R<2> are each H or they combine with each other to form an (un)satd.arom. or heterocyclic ring condensed with a heterocyclic ring; Ar<1> and Ar<2> are each (substd.) 6-20C aryl or (substd.) 5-18C heterocyclic; substituting groups are each 1-6C alkyl, 1-6C alkoxy, 6-18C aryloxy, phenyl, nitro, cyano, amino, hydroxyl, or halogen provided they may combine with each other to form an (unsatd.) 5- or 6-membered ring; and Ar<3> is (substd.) arylene or a single bond] is sandwiched between an anode having a sheet resistance of several hundreds of OMEGA/mm or lower, a film thickness of 10nm to 1mum, and a transmission of 10% or higher and a cathode having a sheet resistance of several hundreds of OMEGA/mm or lower and a film thickness of 10nm to 1mum.

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. More specifically, the present invention relates to an organic electroluminescence device having excellent thin film properties and cathode adhesion.

[0002]

2. Description of the Related Art Electroluminescence element (hereinafter abbreviated as EL element) has high visibility due to self-luminous property, and has excellent impact resistance because it is a completely solid state element. have. Current,
An EL element that is put to practical use is a dispersion type EL element.
This is one in which an alternating voltage is applied to the light emitting layer in which the fluorescent material is dispersed to emit light, but it is necessary to apply an alternating voltage of several tens of volts and 10 kHz or more, and the driving circuit thereof is complicated. In recent years, organic compounds have been used as light emitting layer materials.
An organic EL device that can be driven by a DC voltage of about 0 V has been developed (CWTong and SAVanSlyke, Appl. Phys. Lett., Vo
l.51, pp.913-915 (1987). These organic EL elements are
It is a laminated type of transparent electrode / hole injection layer / light emitting layer / back electrode, and the film thickness between the electrodes must be 1 μm or less. Therefore, depending on the compound used for the light emitting layer, there is a problem that pinholes are likely to occur and the productivity is low. In order to prevent this pinhole, the thin film property of the device has become very important. In addition, an element structure in which an electron injection layer is provided as necessary to improve the light emitting property is disclosed. For example, an electron injection layer using an aluminum chelate complex (Japanese Patent Application Laid-Open No. Hei 3)
No. 163186 and No. 3-163187) or an electron injection layer using an oxadiazole derivative (Appl. Phys. Lett., Vol. 55 (1989), pp. 1489, JP-A-3).
-35083 and 3-35084). In such an electron injection layer, the adhesion to the cathode and the thin film property of itself are important, but there is a problem with the thin film property, and uniform light emission is not obtained. In addition, a light emitting material using a compound containing an aromatic heterocycle (Japanese Patent Application Laid-Open No. Hei.
No. 103571), the adhesive property is excellent, but the thin film property is inferior.

[0003]

Therefore, the inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks of the prior art and to develop an organic electroluminescent device having improved adhesion to the cathode and excellent thin film properties. It was As a result, they have found that the above object can be sufficiently achieved by introducing two aromatic rings at the vinyl terminal of a compound containing an aromatic heterocycle to disturb the regularity of molecular stacking. The present invention has been completed based on such findings.

That is, according to the present invention, in an electroluminescent device composed of one or more layers of organic compound sandwiched between an anode and a cathode, at least one organic compound is represented by the general formula (I).

[0005]

[Chemical 2]

(Wherein A represents a carbon atom or a nitrogen atom, R ¹ and R ² are both hydrogen atoms, a saturated or unsaturated aromatic ring in which both are bonded to form a heterocycle, or a saturated or unsaturated aromatic ring). Represents a saturated heterocycle, Ar ¹ and A
r ² represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted heterocyclic ring having 5 to 18 carbon atoms. Here, 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, a nitro group, a cyano group, an amino group, a hydroxyl group or halogen. Indicates an atom. Further, these substituents may be the same or different, and the substituents may be bonded to each other to form a saturated or unsaturated five-membered ring or six-membered ring. Ar ³ may be a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a single bond. ) A heterocycle-containing styryl compound represented by the formula (1) is provided.

The present invention is a heterocycle represented by the general formula (I)
The contained styryl compound is used as a constituent component of the organic EL device.
This component is sandwiched between the anode and cathode of the organic EL device.
As a material for a layer that has been
It constitutes an EL element. Where Ar¹and
Ar²Is a substituted or unsubstituted aryl having 6 to 20 carbon atoms.
Group (eg phenyl group, naphthyl group, biphenyl
Group, terphenyl group, anthracenyl group, pyrenyl group
Or a heterocyclic group having 5 to 18 carbon atoms (for example,
For example, pyridyl group, quinolyl group, carbazolyl group, oxa
Diazolyl group). These are single substitutions
Or a plurality of them may be substituted. Also, Ar³Is replaced
Or an unsubstituted arylene group having 6 to 20 carbon atoms (for example,
For example, phenylene group, naphthylene group, biphenylene group,
-Phenylene group, anthracenediyl group, pyrenediyl group
Group) or a single bond. With the above substituents
Is an alkyl group having 1 to 6 carbon atoms (for example, methyl
Group, ethyl group, n-propyl group, i-propyl group, n-
Butyl group, i-butyl group, sec-butyl group, t-butyl group
Group, i-pentyl group, t-pentyl group, neopentyl group
Group, n-hexyl group, i-hexyl group, etc.), carbon number 1
~ 6 alkoxy groups (eg methoxy, ethoxy
Group, propoxy group, i-propoxy group, butyloxy
Group, i-butyloxy group, sec-butyloxy group, i
-Pentyloxy group, t-pentyloxy group, n-hexyl
Siloxy group), aryloxy having 6 to 18 carbon atoms
Groups (eg, phenoxy group, naphthyloxy group, etc.),
Phenyl group, nitro group, cyano group, amino group (amine,
Dimethylamine, diethylamine, diphenylamine, etc.
Etc.) indicates a hydroxyl group or a halogen atom and is
Or a plurality of them may be substituted. Also, the general formula
Heterocycle of heterocycle-containing styryl compound represented by (I)
Is A, R ¹And R²Various structures shown below by
Can be mentioned. (1) When A is a carbon atom R¹= R²= H

[0008]

[Chemical 3]

When R ¹ and R ² are condensed or saturated aromatic rings

[0010]

[Chemical 4]

When R ¹ and R ² are condensed or saturated heterocyclic rings

[0012]

[Chemical 5]

(2) When A is a nitrogen atom, R ¹ = R ² = H

[0014]

[Chemical 6]

When R ¹ and R ² are condensed or unsaturated aromatic rings

[0016]

[Chemical 7]

When R ¹ and R ² are condensed or saturated heterocyclic rings

[0018]

[Chemical 8]

As the organic compound represented by the general formula (I) containing the above heterocycle, various compounds can be mentioned, for example,

[0020]

[Chemical 9]

[0021]

[Chemical 10]

[0022]

[Chemical 11]

[0023]

[Chemical 12]

[0024]

[Chemical 13]

[0025]

[Chemical 14]

[0026]

[Chemical 15]

[0027]

[Chemical 16]

[0028]

[Chemical 17]

[0029]

[Chemical 18]

[0030]

[Chemical 19]

[0031]

[Chemical 20]

And the like. The heterocyclic styryl compound represented by the general formula (I) has two olefin moieties (= C = CH-) in one molecule. Due to the geometrical isomerism of the olefin moiety, the heterocyclic styryl compound represented by the general formula (I) is roughly classified into a combination of cis and trans isomers, and the heterocyclic styryl compound of the present invention may be any of them. Well, it may be a mixture.

The organic compound represented by the above general formula (I) can be produced by a conventional method, preferably by the Arbusow-Michaelis reaction. This Arbusow-Michael
The is reaction consists of the following reactions. First, the following general formula

[0034]

[Chemical 21]

(In the formula, X represents a halogen atom, and R ¹ ,
R ² , A and Ar ³ are the same as above. ) And a halomethyl compound represented by the following general formula

[0036]

[Chemical formula 22]

By reacting a trialkyl phosphite or triphenyl phosphite represented by the formula (wherein R represents an alkyl group having 1 to 4 carbon atoms or a phenyl group), general formula (II)

[0038]

[Chemical formula 23]

(Wherein R, R ¹ , R ² , A and Ar ³
Is the same as above. ) The phosphonate ester represented by The resulting phosphonate ester was treated with the compound of the general formula (III) in the presence of a base.

[0040]

[Chemical formula 24]

The organic compound represented by the general formula (I) can be obtained by the coupling reaction with the ketone represented by the formula (wherein Ar ¹ and Ar ² are the same as above). As the reaction solvent used here, hydrocarbons, alcohols and ethers are preferably used. Specifically, methanol; ethanol; isopropanol;
Butanol; 2-methoxyethanol; 1,2-dimethoxyethane; bis (2-methoxyethyl) ether; dioxane; tetrahydrofuran; toluene; xylene;
Dimethyl sulfoxide; N, N-dimethylformamide; N-methylpyrrolidone; 1,3-dimethyl-2-imidazolidinone and the like. Of these, tetrahydrofuran and dimethyl sulfoxide are preferable. As the condensing agent, caustic soda, caustic potash, sodium amide, sodium hydride, n-butyllithium, sodium methylate and alcoholates such as potassium t-butoxide are preferable, and n-butyllithium and potassium t-butoxide are particularly preferable. . The reaction temperature cannot be uniquely determined depending on the type and conditions of the reaction raw materials used, but usually a wide range from room temperature to about 100 ° C. can be selected, and room temperature is particularly preferable.

The heterocycle-containing styryl compound of the present invention thus obtained (hereinafter referred to as "styryl compound")
Can be effectively used as a material for an EL element capable of emitting light with high brightness at a low voltage. The styryl compound of the present invention has excellent electrode adhesion and thin film properties,
Uniform light emission is obtained as a whole. Furthermore, this styryl compound has the advantage that even if it is heated to the vapor deposition temperature, a uniform amorphous thin film can be formed without decomposition or deterioration, and pinholes do not form. As described above, the styryl compound represented by the general formula (I) of the present invention is used for various constituent layers, and is particularly effective as a light emitting layer (or an electron injecting and transporting layer) in an EL device. First, the light emitting layer will be described. This light emitting layer can be formed by thinning the compound of the general formula (I) by a known method such as a vapor deposition method, a spin coating method, or a casting method. However, 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 the gas phase state, or a film formed by solidifying from the solution state or liquid phase state of the compound, for example, a vapor deposition film, etc. Can be distinguished from a thin film (molecular cumulative film) formed by the LB method. Further, as disclosed in JP-A-59-194393, etc., the light-emitting layer is prepared by dissolving a binder such as a resin and the compound in a solvent to form a solution, which is then spin-coated. For example, it can be formed into a thin film. The thin film of the light emitting layer thus formed is not particularly limited and can be appropriately selected depending on the situation, but is usually 5 nm to 5 μm.
It is selected in the range of. The light emitting layer in this EL element is
(1) An injection function capable of injecting holes from the anode or the hole injecting and transporting layer and applying electrons from the cathode or the electron injecting and transporting layer when an electric field is applied, (2) injected charges (electrons And (hole) are moved by the force of an electric field, and (3) a field for recombination of electrons and holes is provided inside the light-emitting layer, and this is used as a light-emitting function.
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 charges. Since the compound represented by the general formula (I) used for the light emitting layer generally has an ionization energy of less than about 6.0 eV, 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 modes. Basically, the light emitting layer is sandwiched between a pair of electrodes (anode and cathode). A hole injecting / transporting layer or an electron injecting / transporting layer may be interposed as necessary. As the intervening method, there are mixing into the polymer and simultaneous vapor deposition. Specifically, (1) anode / light emitting layer / cathode, (2) anode / hole injection / transport layer / light emitting layer / cathode,
(3) Anode / hole injecting / transporting layer / light emitting layer / electron injecting / transporting layer / cathode can be mentioned. The hole injecting and transporting layer and the electron injecting and transporting layer are not always necessary, but the presence of these layers further improves the light emitting performance. Further, in the element having the above structure, it is preferable that all are supported by a substrate, and the substrate is not particularly limited,
What is conventionally used for EL elements, for example, those made of glass, transparent plastic, quartz or the like can be used. As the anode in this EL element, a material having a large work function (4 eV or more), a metal, an alloy, an electrically conductive compound or a mixture thereof as an electrode substance is preferably used. Specific examples of such an electrode material include a metal such as Au and a dielectric transparent material 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 the electrode is preferably several hundred Ω / mm or less. Further, the film thickness depends on the material, but is usually 10 nm to 1 μm, preferably 10 to 20.
It is selected in the range of 0 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 substance 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. The sheet resistance as an electrode is preferably several hundred Ω / mm 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 constitutions as described above, and the hole injecting and transporting layer in the EL device having the constitution (2) or (3) is
A layer composed of a hole-transporting compound, which has a function of transferring holes injected from the anode to the light-emitting layer, and 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 at a low electric field, and further,
The electrons injected from the cathode or the electron injecting and transporting layer into the light emitting layer are accumulated near the interface in the light emitting layer due to the barrier of electrons existing at the interface between the light emitting layer and the hole injecting and transporting layer, and the luminous efficiency is improved. The device has excellent light emitting performance. The hole transporting 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 hole transporting compound is appropriately transferred to the light emitting layer. It is preferable that the compound has a hole mobility of at least 10 ⁻⁶ cm ² / V · second when an electric field of 10 ⁴ to 10 ⁶ V / cm is applied. 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 following porphyrin compounds (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.

As a typical example of the porphyrin compound,
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-
4,4'-diaminobiphenyl; N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diaminobiphenyl; 2,2-bis (4-di-p-tolylamino) Phenyl) propane; 1,1-bis (4-di-p
-Tolylaminophenyl) cyclohexane; N, N,
N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl; 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) -4,4'-diaminobiphenyl; 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-diphenylaminostilbene; N-phenylcarbazole and the like.

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 injection layers. On the other hand, the electron injecting and transporting layer in the EL device having the structure (3) is composed of an electron transfer compound,
It has a function of transmitting electrons injected from the cathode to the light emitting layer. 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:

[0050]

[Chemical 25]

A nitro-substituted fluorenone derivative such as

[0052]

[Chemical formula 26]

Thiopyran dioxide derivatives such as

[0054]

[Chemical 27]

Diphenylquinone derivatives such as ["Polymer Preprints, Japan"
Volume 37, No. 3, 681 (1988), etc.], or

[0056]

[Chemical 28]

Compounds such as [Journal of Applied Physics (J.Apply.Phys.)] 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.). In addition, the following general formulas (IV) and (V)

[0058]

[Chemical 29]

(In the formula, Ar ^{4 to} Ar ⁶ and Ar ⁸ each independently represent an aryl group, and Ar ⁷ represents an arylene group. These aryl groups and arylene groups may or may not be substituted. May be used). Here, examples of the aryl group include a phenyl group, naphthyl group, biphenyl group, anthranyl group, perylenyl group, pyrenyl group, and the like, and examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthracenylene group, a perylenylene group, Examples thereof include a pyrenylene group. Moreover, as a substituent, a C1-C10 alkyl group, a C1-C10 alkoxy group, a cyano group, etc. are mentioned. The compounds represented by the general formulas (IV) and (V) are preferably those capable of forming a thin film. Specific examples of the compounds represented by the general formulas (IV) and (V) include:

[0060]

[Chemical 30]

[0061]

[Chemical 31]

[0062]

[Chemical 32]

And the like. Note that the hole injecting and transporting layer and the electron injecting and transporting layer are layers having any of an electron injecting property, a transporting property, and an obstacle property.
It is also possible to use a crystalline or non-crystalline material such as a system type, a SiC type, a CdS type. The hole injecting and transporting layer and the electron injecting and transporting 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 and transporting layer using the inorganic material can be formed by the vacuum deposition method, the sputtering, etc. However, it is preferable to form it by the vacuum vapor deposition method for the same reason as in the case of the light emitting layer regardless of whether organic or inorganic material is used.

[0064]

The present invention will be described in more detail with reference to Synthesis Examples, Examples and Comparative Examples. The invention is in no way limited by these examples. Synthesis example 1

[0065]

[Chemical 33]

5.0 g (0.015 mol) of 2,3-bis (bromomethyl) quinoxaline (manufactured by Aldrich) and 10 ml of triethyl phosphite were placed in a three-necked flask, the oil bath temperature was 100 ° C., and the temperature inside the flask was 80. ~ 8
The mixture was heated and stirred at 4 ° C for 2 hours. After cooling, the grayish white precipitate is removed.
-Washed with 100 ml of hexane and dried under reduced pressure. As a result, 6.7 g (quantitative) of off-white powder (A) was obtained. The melting point of this off-white powder (A) was 91 to 93 ° C. The measurement results of the proton nuclear magnetic resonance ( ¹ H-NMR) spectrum of the obtained off-white powder (A) are shown below. ¹ H-NMR (solvent: CDCl ₂ , standard: tetramethylsilane (TMS)) δ (ppm) = 7.5-8.1 (m, 4H: H of quinoxaline skeleton) δ (ppm) = 3.9- 4.5 (q, 8H: ethoxy) δ (ppm) = 3.9 ( d, 4H: -CH 2 -, J = 12
Hz) δ (ppm) = 1.4 (t, 12H: ethoxy group) Next, 1.3 g (3.02 ×) of the phosphonate ester of (A).
10 ^-3 mol) and benzophenone 1.2 g (6.58 × 10 ^-3)
(Mol) was suspended in 50 ml of dimethyl sulfoxide (DMSO) at room temperature under an argon gas stream. 0.6 g of potassium t-butoxide (5.35 x 10
^-3 mol) was added, the reaction solution immediately exhibited a reddish brown suspension. After stirring at room temperature for 8 hours, ice 50 gh
e, and extracted with 100 ml of methylene chloride. The methylene chloride phase was dried over potassium carbonate and purified by a silica gel column to give a yellow eluate. After removing the solvent of the obtained eluate, acetone:
Recrystallization was carried out with n-hexane = 1: 9 (volume / volume). As a result, 0.3 g of white needle crystals (yield: 22%) were obtained. The melting point of the obtained white needle crystal is 152 to 1
It was 53 ° C. Further, as a result of mass spectrometry of the obtained white needle-like crystals, only a peak of m / Z = 486 was obtained,
It was confirmed that (B) (hereinafter abbreviated as DPVQ) was synthesized. The measurement results of the obtained DPVQ absorption spectrum (in DMF) are shown below. 270 nm (2.4 × 10 ⁴ cm ^-1 · mol ⁻¹ · liter) 300 nm (2.5 × 10 ⁴ cm ⁻¹ · mol ⁻¹ · liter) 360 nm (1.3 × 10 ⁴ cm ⁻¹ · mol ^{−) 1} liter)

Synthesis Examples 2 to 6 The compound species shown in Table 1 were synthesized in the same manner as in Synthesis Example 1 except that benzophenone was changed to the corresponding ketone.

Synthesis Example 7 Table 1 (Synthesis Example 1) was repeated except that the phosphonate ester of (A) used in Synthesis Example 1 was replaced with the phosphonate ester of 6,7-dimethylquinoxaline shown below. ) And () were synthesized.

[0069]

[Chemical 34]

[0070]

[Table 1]

[0071]

[Table 2]

Synthesis Example 8

[0073]

[Chemical 35]

[0074]

[Chemical 36]

2.0 g of 4,4'-dimethylbenzyl (8.3
× 10^-3Mol), N-bromosuccinimide (NBS)
3.0 g (0.0168 mol) and benzoyl peroxide 0.1
4g (5.8 × 10^-FourMol) to 100 milliliters of carbon tetrachloride
Suspended in tor. Return this for 2 hours at an external temperature of 100 ° C
It was stirred by flowing. After leaving it overnight, the formed yellow precipitate is removed with methanol.
1.7g yellow powder after washing twice with 100ml
(C) was obtained (yield: 50%). Of this yellow powder (C)
The melting point was 196-197 ° C. Yellow powder obtained
(C)¹The measurement results of the H-NMR spectrum are shown below.
You ¹ 1 H-NMR (solvent: CDCl₂, Standard: Tetramethyl
Silane (TMS)) δ (ppm) = 7.4 to 8.0 (q, 8H: H of aromatic ring) δ (ppm) = 4.5 (q, 4H: methyl bromide group) Then, (C) 1.6 g (4.0 × 1)
0^-3Mol) and 0.5 g of o-phenylenediamine (4.6 x 1)
0^-3Mol) in 70 ml of acetic acid at 80 ° C
The mixture was heated and stirred for 30 minutes. After the reaction was completed, the white precipitate obtained
Was washed twice with 50 ml of water, and the silica gel column was washed.
As a result of purification (developing solution: methylene chloride) at
1.8 g (yield: 96%) of powder (D) was obtained. Obtained
The melting point of the white powder was 172-173 ° C. Got
Nuclear magnetic resonance of the white powder (D) (¹H-NM
R) The measurement result of the spectrum is shown below.¹ 1 H-NMR (solvent: CDCl₂, Standard: Tetramethyl
Silane (TMS)) δ (ppm) = 8.3 (m, 12H: quinoxaline skeleton
And H of aromatic ring) δ (ppm) = 4.5 (s, 4H: methyl bromide group) 1.8 g (3.8 x 10) of obtained (D)^-3Mol) to phosphorus
Add 12 ml of triethyl acid and add 3 at internal temperature of 85 ℃.
The mixture was heated and stirred for hours. After standing overnight, the white precipitate obtained was n
-Light yellow powder as a result of washing with 50 ml of hexane
The powder (E) 1.4g (yield: 64%) was obtained. Got
The melting point of the pale yellow powder was 129 to 131 ° C. Got
Of pale yellow powder (E)¹Measurement of 1 H-NMR spectrum
The results are shown below.¹ 1 H-NMR (solvent: CDCl₂, Standard: Tetramethyl
Silane (TMS)) δ (ppm) = 8.3 to 7.0 (m, 12H: quinoxaline
H of skeleton and aromatic ring) δ (ppm) = 4.1 (q, 8H: ethoxy group) δ (ppm) = 3.2 (d, 4H: -CH)₂P, J = 16
Hz) δ (ppm) = 1.3 (t, 12H: ethoxy group) 1.4 g (2.6 × 10) of the obtained phosphonate ester (E)
^-3Mol), benzophenone 1.0 g (5.5 × 10^-3Guinea pig
And potassium-t-butoxide 0.6 g (5.3 × 1)
0^-3Mol) to 50 ml of dimethyl sulfoxide
Suspended. This at room temperature under an argon gas atmosphere
The mixture was stirred under reflux for 3 hours. After leaving it overnight, methanol is added to the crime liquid.
50 ml was added and the deposited precipitate was collected by filtration. Shi
Purification (developing solution: methylene chloride) is performed on the Rica gel column.
Then, the desired fraction is added to acetone / n-hexane.
Recrystallize with the mixed solution to obtain 0.9 g of yellow powder (F).
Obtained (yield: 37%). The melting point of this yellow powder (F) is
The temperature was 198 to 199 ° C. Of the obtained yellow powder (F)
¹The measurement results of the 1 H-NMR spectrum are shown below. ¹ 1 H-NMR (solvent: CDCl₂, Standard: Tetramethyl
Silane (TMS)) δ (ppm) = 6.7 to 8.2 (m, 34H: aromatic ring, quino
Xaline ring and -H of = C = HC) Further, as a result of mass spectrometry of the obtained yellow powder, m / Z = 6.
Only 38 peaks were obtained, and (F) (DPVPQ) was
I confirmed that it was made.

Synthesis Example 9 The compound species shown in Table 1 () was synthesized in the same manner as in Synthesis Example 8 except that benzophenone was changed to 4,4'-dimethylbenzophenone.

[0077]

[Table 3]

Example 1 On a glass substrate of 25 mm × 75 mm × 1.1 mm (HO
YA, NA40) with 100 n of ITO by vapor deposition
The film having a thickness of m (made by HOYA, corresponding to the anode) was used as a transparent support substrate. This substrate was ultrasonically cleaned in isopropyl alcohol for 5 minutes and further in pure water for 5 minutes, and then dried by blowing nitrogen, and a UV ozone cleaning device (U
V300, manufactured by Samco International Laboratories Inc.)
Was washed at a substrate temperature of 150 ° C. for 20 minutes. On this transparent support substrate, fixed to a substrate holder of a commercially available vacuum deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.), 200 mg of Cu-coordinated phthalocyanine (hereinafter abbreviated as CuPc) was put in a molybdenum resistance heating boat, In another molybdenum resistance heating boat, N'-bis (3-methylphenyl) -N, N'-diphenyl (1,1'-biphenyl) -4,4'-diamine (hereinafter abbreviated as TPD (p)). 200 mg of 4,4'-bis (2,2-diphenylvinyl) biphenyl (hereinafter abbreviated as DPVBi) in another resistance heating boat made of molybdenum.
mg was added, and the inside of the vacuum chamber was depressurized to 1 × 10 −4 Pa.
Then, the boat containing CuPc was heated to about 350 ° C., and CuPc was vapor-deposited on the ITO film at a vapor deposition rate of 0.1 to 0.3 nm / sec to form a CuPc layer having a thickness of 20 nm. At this time, the temperature of the substrate was room temperature. Without removing this from the vacuum tank, the boat containing TPD (p) is heated to about 250 ° C., and the deposition rate is 0.1 to 0.3 n.
TPD (p) was vapor-deposited on the CuPc layer at a rate of m / sec to form a TPD (p) layer having a film thickness of 40 nm. The substrate temperature at this time was room temperature. The two layers, the CuPc layer and the TPD (p) layer thus provided, correspond to the hole transport layer. Next, heat the boat containing DPVBi to about 240 ° C,
DP on the TPD (p) layer at a deposition rate of 0.1 to 0.3 nm / sec.
VBi was vapor-deposited to form a light emitting layer having a thickness of 40 nm. Next, the transparent support substrate on which the three organic layers were formed was taken out from the vacuum layer, a stainless steel mask was placed on the light emitting layer, and the substrate was again fixed to the substrate holder. Moreover, 2,3-bis (2,2-diphenylvinyl) quinoxaline obtained in Synthesis Example 1 (hereinafter,
Abbreviated as DPVQ. ) Was put in a vacuum chamber. Next, a resistance heating boat made of molybdenum containing 1 g of a magnesium ribbon and a basket made of tungsten containing 500 mg of a silver wire were attached to a vacuum chamber. afterwards,
The vacuum chamber was evacuated to 1 × 10 ⁻⁴ Pa. After depressurization, DPV
Heat the boat containing Q by heating it to 216 ° C.
The vapor deposition rate is 0.1 to 0.3 nm / sec.
An electron injecting and transporting layer having a film thickness of 20 nm was provided. Next, the tungsten basket containing the silver wire is energized to deposit silver at a vapor deposition rate of 0.1 nm / sec, and at the same time, the boat containing the magnesium ribbon is energized to deposit vapor rates of 1.4 to 2.
Magnesium was vapor deposited at 0 nm / sec. A 200-nm-thick magnesium-silver layer (corresponding to the cathode) was formed on the DPVQ layer by this binary vapor deposition. As described above, the target organic EL element (ITO / CuPc / TPD
(P) / DPVBi / DPVQ / Mg: Ag) was obtained. As a result of applying a voltage of 10 V to the obtained organic EL device, a current of 3.5 mA / cm ² was flown and a high-intensity blue light emission of 60 cd / m ² was observed. At this time, the luminous efficiency is
It was 0.5 lumen / W. In addition, from the measurement result of the fluorescence spectrum, the peak wavelength of emission is 474 nm, and
It was confirmed that the light was emitted from PVBi. This element is 100c
It was made to emit light with a brightness of d / m ² and was observed using a brightness meter (CS-100, manufactured by Minolta Camera Co., Ltd.). There was no non-light emitting region or light emission unevenness).

Examples 2 to 8 Instead of the DPVQ used as the electron injecting and transporting layer, the second
Organic EL devices were prepared and evaluated in the same manner as in Example 1 except that the compounds shown in the table were used and the heating boat temperature during vapor deposition was changed as shown in Table 2. The results obtained are shown in Table 2.

Comparative Example 1 Instead of the DPVQ used as the electron injecting and transporting layer, the second
Organic EL devices were prepared and evaluated in the same manner as in Example 1 except that the compounds shown in the table were used and the heating boat temperature during vapor deposition was changed as shown in Table 2. The results obtained are shown in Table 2.

Comparative Example 2 An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the electron injecting and transporting layer was not used and the cathode was directly attached to the light emitting material DPVBi. The results obtained are shown in Table 2.

[0082]

[Table 4]

* Evaluation of uniformity ∘: Uniform light emission was observed in the observation region immediately after the device was manufactured and after one day. Δ: The observation area shows uniform light emission immediately after the element is manufactured, but after one day, there is a non-light emission area having a diameter of 10 μm or less or uneven light emission. X: There is a non-light emitting region having a diameter of 10 μm or less or uneven light emission in the observation region immediately after the element is manufactured or even after one day.

As shown in Comparative Example 1, in the case of using SQ as the electron injecting and transporting layer, the adhesion of the cathode metal is good, but since the thin film property of SQ itself is inferior, crystallization occurs over time. And the uniformity of light emission is poor. Further, as is clear from Comparative Example 2, the element in which the cathode metal is directly attached on the DPVBi of the light emitting material has a good thin film property of the light emitting material, but the adhesion of the metal is very poor, and thus the uniformity of light emission is high. Inferior to

Example 9 A hole injecting and transporting layer was formed in the same manner as in Example 1. Next, DPVPQ200m of Synthesis Example 8 set first
290 by energizing the molybdenum resistance heating boat containing g
It heated up to (degreeC) and vapor-deposited on the said hole injection transport layer at vapor deposition rate of 0.1-0.3 nm / sec, and formed the light emitting layer with a film thickness of 40 nm. Next, the obtained transparent supporting substrate having the hole injecting and transporting layer formed thereon was taken out from the vacuum layer, a stainless steel mask was placed on the hole injecting and transporting layer, and the hole was again fixed to the substrate holder. Next, a resistance heating boat made of molybdenum containing 1 g of a magnesium ribbon and a basket made of tungsten containing 500 mg of a silver wire were attached to a vacuum chamber.
Next, the tungsten basket containing the silver wire is energized to deposit silver at a vapor deposition rate of 0.1 nm / sec, and at the same time, the boat with a magnesium ribbon is energized to deposit magnesium at a vapor deposition rate of 1.4 nm / sec. It was A 150-nm-thick magnesium-silver layer (corresponding to the cathode) was formed on the DPVPQ layer by this binary vapor deposition. As described above, the target organic EL element (ITO / CuPc /
TPD / DPVPQ / Mg: Ag) was obtained. As a result of applying a voltage of 10 V to the obtained organic EL device, 13 m
A / cm ² current flows, 50 cd / m ² Greenish B
Lue emission was observed. At this time, the luminous efficiency is 0.12.
It was lumen / W. In addition, from the measurement result of the fluorescence spectrum, the peak wavelength of emission is 485 nm, and the DPV
It was confirmed that the light was emitted from PQ. This element is 50 cd / m
^When light was emitted at a luminance of ² and observed using a luminance meter (CS-100, manufactured by Minolta Camera Co., Ltd.), it was observed that the observation area had uniform light emission immediately after the element was formed and after one day had elapsed (diameter of 10 μm or more There was no light emitting region or uneven light emission.).

[0086]

As described above, the organic EL device of the present invention is
By using the heterocyclic styryl compound, it is possible to have excellent adhesiveness with a metal and thin film property, and also excellent light emission uniformity. Therefore,
The organic EL element of the present invention is expected to be effectively used as various elements such as an organic EL element.

Claims (3)

[Claims] 1. In an electroluminescent device composed of one or more layers of organic compound sandwiched between an anode and a cathode, the organic compound constituting at least one layer is represented by the general formula (I): (In the formula, A represents a carbon atom or a nitrogen atom, R ¹ and R ² are both hydrogen atoms, a saturated or unsaturated aromatic ring in which both are bonded to form a heterocycle, or a saturated or unsaturated heterocycle. Ar ¹ and Ar ² represent a substituted or unsubstituted aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted heterocyclic ring having 5 to 18 carbon atoms.
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, a nitro group, a cyano group, an amino group, a hydroxyl group or a halogen atom. . Further, these substituents may be the same or different, and the substituents may be bonded to each other to form a saturated or unsaturated five-membered ring or six-membered ring. Ar ³ is a substituted or unsubstituted C 6 to C 20
May be an arylene group or a single bond. ) A heterocycle-containing styryl compound represented by the formula (1). 2. The organic electroluminescence device according to claim 1, wherein the compound represented by the general formula (I) is used as a constituent component of the light emitting layer. 3. The organic electroluminescence device according to claim 1, wherein the compound represented by the general formula (I) is used as a constituent component of the electron injecting and transporting layer.