JP3228301B2 - Organic electroluminescence device - Google Patents

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 particularly, the present invention is a heterocyclic ring-containing styryl compound of the thin film resistance and cathodic deposition with excellent electroluminescent element <br/> Contact Keru for electron injection transport and
The present invention relates to an organic electroluminescence device using the same.

[0002]

2. Description of the Related Art Electroluminescent devices (hereinafter abbreviated as EL devices) are characterized by high visibility due to self-emission and excellent impact resistance due to being a completely solid device. have. Current,
An EL element used in practice is a dispersion-type EL element.
In this method, an AC voltage is applied to a light emitting layer in which phosphors are dispersed to emit light. However, it is necessary to apply an AC voltage of several tens of V and 10 kHz or more, and the driving circuit is complicated. In recent years, organic compounds have been
Organic EL devices that can be driven with a DC voltage of about 0 V have been developed (CWTong and SAVan Slyke, Appl. Phys. Lett., Vo
l.51, pp.913-915 (1987). These organic EL elements are
It is a laminated type of a transparent electrode / a hole injection layer / a light emitting layer / a back electrode, and the film thickness between the electrodes needs to be 1 μm or less. Therefore, there is a problem that a pinhole is easily generated depending on the compound used for the light emitting layer, and the productivity is low. In order to prevent this pinhole, the thin film property of the element has become very important. Further, an element configuration in which an electron injection layer is provided as necessary to improve light emission is disclosed. For example, an electron injection layer using an aluminum chelate complex (Japanese Unexamined Patent Application Publication No.
163186 and 3-163187) or an electron injection layer using an oxadiazole derivative (Appl. Phys. Lett., Vol. 55 (1989), pp. 1489, Japanese Unexamined Patent Publication No.
-35083 and 3-35084). In such an electron injection layer, adhesion to the cathode and its own thin film property are important, but there is a problem in the thin film property, and uniform light emission has not been obtained. Further, a light emitting material using a compound containing an aromatic heterocyclic ring (Japanese Patent Laid-Open No.
-103571) is excellent in adhesion but inferior in thin film properties.

[0003]

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

[0004] The present invention includes an anode and an organic compound for your Keru electron injecting and transporting the light emitting element including an organic compound one or more layers interposed between the cathode
Has the general formula (I)

[0005]

Embedded image

(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 heterocyclic ring, or a saturated or unsaturated 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 means 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. Indicates an atom. These substituents may be the same or different, and the substituents may be combined with each other to form a saturated or unsaturated 5- or 6-membered ring. Ar ³ may be a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a single bond. The present invention provides a heterocyclic-containing styryl compound represented by the formula:

According to the present invention, a heterocyclic-containing styryl compound represented by the general formula (I) is used as a component for injecting and transporting electrons in an organic EL device. This constituent component becomes a material of a layer sandwiched between the anode and the cathode of the organic EL element, and constitutes the organic EL element as one or more layers. Here, Ar ¹ and Ar ² represent a substituted or unsubstituted aryl group having 6 to 20 carbon atoms (eg, phenyl, naphthyl, biphenyl, terphenyl, anthracenyl, pyrenyl, etc.), or It represents a heterocyclic group of Formulas 5 to 18 (for example, a pyridyl group, a quinolyl group, a carbazolyl group, an oxadiazolyl group, and the like). They are,
It may be single substituted or plural substituted. Ar ³ represents a substituted or unsubstituted arylene group having 6 to 20 carbon atoms (for example, a phenylene group, a naphthylene group, a biphenylene group, a terphenylene group, an anthracenediyl group, a pyrenidiyl group, etc.), or may be a single bond. . Examples of the substituent include an alkyl group having 1 to 6 carbon atoms (eg, 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, etc.), carbon number 1 to 6 alkoxy groups (e.g., methoxy, ethoxy, propoxy, i-propoxy,
A butyloxy group, an i-butyloxy group, a sec-butyloxy group, an i-pentyloxy group, a t-pentyloxy group, an n-hexyloxy group, etc., and an aryloxy group having 6 to 18 carbon atoms (for example, phenoxy group, naphthyloxy) A phenyl group, a nitro group, a cyano group, an amino group (amine, dimethylamine, diethylamine, diphenylamine, etc.), a hydroxyl group or a halogen atom, which may be monosubstituted or plurally substituted.
The heterocycle of the heterocycle-containing styryl compound represented by the general formula (I) may have various structures shown below depending on A, R ¹ and R ² . (1) When A is a carbon atom When R ¹ = R ² = H

[0008]

Embedded image

When R ¹ and R ² are a condensed saturated or unsaturated aromatic ring

[0010]

Embedded image

When R ¹ and R ² are a condensed saturated or unsaturated heterocyclic ring

[0012]

Embedded image

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

[0014]

Embedded image

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

[0016]

Embedded image

When R ¹ and R ² are condensed saturated or unsaturated heterocycles

[0018]

Embedded image

As the organic compound represented by the general formula (I) containing the above heterocyclic ring, various compounds can be mentioned.

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

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) can be roughly classified into a combination of a cis-form and a trans-form, but the heterocyclic styryl compound of the present invention may be any of them. They may be mixed.

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

[0034]

Embedded image

(Wherein X represents a halogen atom, and R ¹ ,
R ² , A and Ar ³ are the same as described above. ) And the following general formula

[0036]

Embedded image

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

[0038]

Embedded image

Wherein R, R ¹ , R ² , A and Ar ³
Is the same as above. Is obtained. The obtained phosphonic acid ester is reacted with a compound of the formula (III) in the presence of a base.

[0040]

Embedded image

(Wherein Ar ¹ and Ar ² are the same as those described above), whereby an organic compound represented by the general formula (I) can be obtained by a coupling reaction. 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;
Dimethyl sulfoxide; N, N-dimethylformamide; N-methylpyrrolidone; 1,3-dimethyl-2-imidazolidinone. Among them, tetrahydrofuran and dimethyl sulfoxide are preferred. As the condensing agent, sodium hydroxide, potassium hydroxide, sodium amide, sodium hydride, n-butyllithium, sodium methylate and an alcoholate such as potassium-t-butoxide are preferable, and n-butyllithium and potassium-t-butoxide are particularly preferable. . The reaction temperature cannot be unambiguously determined depending on the type and conditions of the reaction raw materials to be used, but it can be selected from a wide range from room temperature to about 100 ° C., and room temperature is particularly preferred.

The thus obtained heterocyclic-containing styryl compound of the present invention (hereinafter referred to as styryl compound).
Can be effectively used as a material for an EL device capable of emitting light with high luminance at a low voltage. The styryl compound of the present invention has excellent electrode adhesion and thin film properties,
Uniform light emission can be obtained as a whole. Further, this styryl compound has the advantages that a uniform amorphous thin film can be formed without decomposition or deterioration even when heated to a vapor deposition temperature, and that pinholes are not generated. As already mentioned, the general formula (I) styryl compound represented by the present invention, as initially an electron injection transport layer, but used for various constituent layers, in particular also as a luminescent layer in the EL element <br /> It is effective. First, the light-emitting layer will be described first.
The light-emitting layer, such as vapor deposition, spin coating, by a known method such as casting method, a compound of general formula (I) can be shape formed by thinning, it is preferable that the particular molecular deposit film . Here, the molecular deposition film is a thin film formed by depositing the compound from a gaseous state or a film formed by solidifying the compound from a solution state or a liquid phase state. As shown, this molecular deposition film can be generally distinguished from a thin film (molecule accumulation film) formed by the LB method. The light emitting layer is disclosed in
As disclosed in JP-A-9-194393 and the like,
After a binder such as a resin and the compound are dissolved in a solvent to form a solution, the solution can be formed into a thin film by a spin coating method or the like to form a solution. There is no particular limitation on the thin film of the light emitting layer formed in this way, and it can be appropriately selected according to the situation, but is usually selected in the range of 5 nm to 5 μm. The light emitting layer in this EL element is:
(1) When an electric field is applied, the anode or the hole injection / transport layer can inject holes, and the cathode or the electron injection / transport layer can inject electrons. (2) The injected charge (electrons) (3) transporting electrons and holes by the force of an electric field, and (3) providing a field for recombination of electrons and holes in the light-emitting layer, which is used to emit light.
Note that there may be a difference between the ease of injecting holes and the ease of injecting electrons, and the transport ability 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 in the light emitting layer generally has an ionization energy of less than about 6.0 eV, it is relatively easy to inject holes if an appropriate anode metal or anode compound is selected. Further, since the electron affinity is higher than about 2.8 eV, if an appropriate cathode metal or cathode compound is selected, it is relatively easy to inject electrons, and also excellent in the ability to transport electrons and holes. Further, since the solid-state fluorescence is strong, the ability to convert an excited state formed at the time of recrystallization of electrons and holes of the compound or its aggregate or crystal, to light is large.

The EL device using the compound of the present invention has various configurations. Basically, the light emitting layer and the electron injection / transport layer are sandwiched between a pair of electrodes (anode and cathode). And if necessary, a hole injection transport layer, etc.
The it is sufficient to intervention. Methods of interposition include mixing into a polymer and simultaneous vapor deposition. Specifically it can be mentioned (1) anode / light emitting layer / electron injection transport layer / cathode, (2) positive electrode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode configuration, such as. The hole injecting and transporting layer is not necessarily required, but the presence of these layers further improves the light emitting performance. In addition, in the device having the above-described structure, it is preferable that each of the devices is supported by a substrate, and the substrate is not particularly limited, and is made of a material conventionally used in an EL device, such as glass, transparent plastic, or quartz. Can be used. As the anode in this EL element, a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more) as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au, CuI, ITO, SnO ₂ , Z
A dielectric transparent material such as nO is used. The anode can be produced by forming a thin film from these electrode substances by a method such as vapor deposition or sputtering. When light is extracted from this electrode, the transmittance is set to 1
It is desirable to make it larger than 0%, and the sheet resistance as an electrode is preferably several hundred Ω / mm or less. Further, the film thickness depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

On the other hand, as the cathode, a metal, an alloy, an electrically conductive compound having a small work function (4 eV or less), and a mixture thereof as an electrode material are used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, a magnesium / copper mixture, Al / AlO ₂ , and indium. The cathode can be manufactured 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 / mm or less, and the film thickness is usually 10 nm.
To 1 μm, preferably in the range of 50 to 200 nm. In this EL device, it is convenient that one of the anode and the cathode is transparent or translucent because it transmits light, so that the efficiency of extracting light is good.

The constitution of the EL device using the compound of the present invention has various modes as described above, and the hole injecting / transporting layer in the EL device having the constitution (2 ) has a hole transporting property. A layer made of a compound, having a function of transmitting holes injected from the anode to the light-emitting layer, and interposing the hole-injection / transport layer between the anode and the light-emitting layer, so that a lower electric field is applied. Many holes are injected into the light-emitting layer, and the electrons injected into the light-emitting layer from the cathode or the electron-injection / transport layer are scattered by an electron barrier present at the interface between the light-emitting layer and the hole-injection / transport layer. An element having excellent light-emitting performance, for example, being accumulated near the interface in the layer and improving the light-emitting efficiency. The hole transport compound used in the hole injection transport layer is disposed between two electrodes to which an electric field is applied, and when holes are injected from an anode,
Compounds capable of appropriately transmitting the holes to the light-emitting layer, for example, those having a hole mobility of at least 10 ⁻⁶ cm ² / V · sec when an electric field of 10 ⁴ to 10 ⁶ V / cm is applied. It is suitable. There is no particular limitation on such a hole transporting compound as long as it has the above preferable properties.
As the photoconductive material, any one can be selected from those commonly used as a charge transporting material for holes and known materials used for a hole injecting and transporting layer of an EL device.

As the charge transporting material, for example, a triazole derivative (as described in US Pat. No. 3,112,197) and an oxadiazole derivative (US Pat.
89,447), imidazole derivatives (described in JP-B-37-16096, etc.), polyarylalkane derivatives (US Pat. No. 3,611)
5,402, 3,820,989, 3,5
No. 42,544, Japanese Patent Publication No. 45-555, 5
1-110983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55-108667, and JP-A-55-15695.
Nos. 3 and 56-36656), pyrazoline derivatives and pyrazolone derivatives (U.S. Pat. Nos. 3,180,729 and 4,278,746; No. 88064, 55-8806
No. 5, No. 49-105537, No. 55-51
Nos. 086 and 56-80051 and 56-8
Nos. 8141 and 57-45545 and 54-
And phenylenediamine derivatives (U.S. Pat. No. 3,615,404, JP-B-51-10105, JP-B-46-3712, and JP-A-47-47). JP-A-25-25336, JP-A-54-53435, JP-A-54-1105
Nos. 36 and 54-119925) and arylamine derivatives (U.S. Pat. No. 3,567,4).
50, 3,180,703, 3,24
Nos. 0,597, 3,658,520 and 4,2
No. 32,103, No. 4,175,961, No. 4,012,376, JP-B-49-35702, JP-A-39-27577, and JP-A-55-1442.
Nos. 50, 56-119132 and 56-2
No. 2437, West German Patent No. 1,110,518, etc.), amino-substituted chalcone derivatives (U.S. Pat. No. 3,526,501) and oxazole derivatives (U.S. Pat. No. 3,526,501). No. 3,257,203), styrylanthracene derivatives (described in JP-A-56-46234, etc.), and fluorenone derivatives (described in JP-A-54-110837). ), Hydrazone derivatives (US Pat. No. 3,71
No. 7,462, JP-A-54-59143, JP-A-55-52063, JP-A-55-52064,
JP-A-55-46760, JP-A-55-85495, JP-A-57-1350, and JP-A-57-148749.
And stilbell derivatives (JP-A-61-210363, JP-A-61-2284).
No. 51, No. 61-14642, No. 61-72
Nos. 255, 62-47646, 62-3
Nos. 6,674, 62-10652, 62-
Nos. 30255, 60-93445, 60
-94462, JP-A-60-174747, JP-A-60-175052) and the like.

These compounds can be used as a hole transporting compound. The following porphyrin compounds (those described in JP-A-63-295695) are shown below.
And aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412;
Nos. 27033, 54-58445, 54
Nos. 149634, 54-64299, 55-79450, 55-144250, 56-119132, and 61-29555.
No. 8, No. 61-98353, No. 63-295
No. 695), particularly, the aromatic tertiary amine compound is preferably used.

Representative examples of the porphyrin compound include:
Porphyrin; 5,10,15,20-tetraphenyl-21H, 23H-porphyrin copper (II);
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;
Representative examples of the aromatic tertiary compound and styrylamine compound include 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'-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 one or more of these hole transporting compounds, or may be a hole transporting compound of a different kind from the layer. It may be a laminate of injection layers. On the other hand, the electron injecting / transporting layer in the EL device of the present invention has the general formula (I) or the general formula (I)
And has a function of transmitting electrons injected from the cathode to the light emitting layer. General
There is no particular limitation on the electron transfer compound other than the formula (I) , and any compound can be selected from conventionally known compounds. Preferred examples of the electron transfer compound include:

[0050]

Embedded image

Nitro-substituted fluorenone derivatives such as

[0052]

Embedded image

Thiopyran dioxide derivatives such as

[0054]

Embedded image

Diphenylquinone derivatives [“Polymer Preprints, Japan”
Vol. 37, No. 3, page 681 (1988) etc.], or

[0056]

Embedded image

[Journal of Applied Physics], vol. 27,
269 (1988)] and anthraquinodimethane derivatives (JP-A-57-149259, JP-A-58-55450, and 61-22515).
No. 1, No. 61-233750, No. 63-10
4061), fluorenylidenemethane derivatives (JP-A-60-69657 and JP-A-60-69657).
143,768, 61-148159, etc.), anthrone derivatives (JP-A-61-2).
25151, 61-233750, etc.). In addition, the following general formulas (IV) and (V)

[0058]

Embedded image

(Wherein, 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 be substituted or unsubstituted. May be mentioned.). Here, the aryl group includes a phenyl group, a naphthyl group, a biphenyl group, an anthranyl group, a perylenyl group, a pyrenyl group and the like, and the arylene group includes a phenylene group, a naphthylene group, a biphenylene group, an anthracenylene group, a perylenylene group, And a pyrenylene group. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a cyano group. The compounds represented by the general formulas (IV) and (V) are preferably those which can form a thin film. Specific examples of the compounds represented by the general formulas (IV) and (V) include:

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

And the like. 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.
A crystalline or non-crystalline material such as a SiC-based, SiC-based, or CdS-based material can also be used. The hole injecting and transporting layer and the electron injecting and transporting layer using an organic material can be formed in the same manner as the light emitting layer. The hole injecting and transporting layer and the electron injecting and transporting layer using an inorganic material can be formed by vacuum evaporation, sputtering, or the like. However, it is preferable to use a vacuum evaporation method for any of the organic and inorganic materials for the same reason as for the light emitting layer.

[0064]

Now, the present invention will be described in further detail with reference to Synthesis Examples, Examples and Comparative Examples. The present invention is not limited by these examples. Synthesis Example 1

[0065]

Embedded image

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, and the oil bath temperature was 100 ° C. and the temperature in the flask was 80. ~ 8
The mixture was heated and stirred at 4 ° C for 2 hours. After standing to cool, an off-white precipitate
-Washed with 100 ml of hexane and dried under reduced pressure. As a result, 6.7 g (quantitative) of an off-white powder (A) was obtained. The melting point of the 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 to 8.1 (m, 4H: H of quinoxaline skeleton) δ (ppm) = 3.9 to 4.5 (q, 8H: ethoxy group) δ (ppm) = 3.9 (d, 4H: —CH ₂ —, J = 12
Hz) δ (ppm) = 1.4 (t, 12H: ethoxy group) Then, 1.3 g of the phosphonate (A) (3.02 ×
10 ⁻³ mol) and 1.2 g of benzophenone (6.58 × 10 ⁻³⁾
Mol) was suspended in 50 ml of dimethyl sulfoxide (DMSO) at room temperature under an argon gas flow. 0.6 g of potassium tert-butoxide (5.35 × 10
^-3 mol), the reaction solution immediately turned into a red-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 with a silica gel column to give a yellow eluate. After removing the solvent of the obtained eluate, acetone:
Recrystallization was performed with n-hexane = 1: 9 (volume / volume). As a result, 0.3 g (yield: 22%) of white needle crystals was obtained. The melting point of the obtained white needle-like crystals was 152 to 1
53 ° C. In addition, as a result of mass analysis of the obtained white needle-like crystals, a peak of only m / Z = 486 was obtained,
(B) (hereinafter abbreviated as DPVQ) was confirmed to be synthesized. The measurement results of the absorption spectrum (in DMF) of the obtained DPVQ are shown below. ^{270nm (2.4 × 10 4 cm -1} · mol -1 · ^{l) 300nm (2.5 × 10 4 cm} -1 · mol -1 · ^{l) 360nm (1.3 × 10 4 cm} -1 · mol - ¹ liter)

Synthesis Examples 2 to 6 Compounds 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 was prepared in the same manner as in Synthesis Example 1 except that the phosphonate ester of (A) used in Synthesis Example 1 was replaced with the following phosphonate ester of 6,7-dimethylquinoxaline. ) And () were synthesized.

[0069]

Embedded image

[0070]

[Table 1]

[0071]

[Table 2]

Synthesis Example 8

[0073]

Embedded image

[0074]

Embedded image

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 torr. Return it at 100 ° C for 2 hours
The mixture was stirred with flowing. After standing overnight, the yellow precipitate
1.7 g of yellow powder after washing twice with 100 ml
(C) was obtained (yield: 50%). This yellow powder (C)
Melting point was 196-197 ° C. Yellow powder obtained
(C)¹The measurement results of the H-NMR spectrum are shown below.
You. ¹ H-NMR (solvent: CDCl_Two, 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 × 1)
0^-3Mol) is suspended in 70 ml of acetic acid and
The mixture was heated and stirred for 30 minutes. After completion of the reaction, the resulting white precipitate
Was washed twice with 50 ml of water, and the silica gel column was used.
Purification (developing solution: methylene chloride) resulted in white
1.8 g (yield: 96%) of powder (D) was obtained. Obtained
The melting point of the white powder was 172 to 173 ° C. Get
Nuclear magnetic resonance of the white powder (D)¹H-NM
R) The spectrum measurement results are shown below.¹ H-NMR (solvent: CDCl_Two, Standard: tetramethyl
Silane (TMS)) δ (ppm) = 8.3 (m, 12H: quinoxaline skeleton and
And H of the aromatic ring) δ (ppm) = 4.5 (s, 4H: methyl bromide group) 1.8 g (3.8 × 10) of the obtained (D)^-3Mol) to phosphorus
12 ml of triethyl acid was added, and the mixture was heated to
The mixture was heated and stirred for hours. After standing overnight, the resulting white precipitate
-As a result of washing with 50 ml of hexane,
1.4 g (yield: 64%) of powder (E) was obtained. Got
The melting point of the pale yellow powder was 129 to 131 ° C. Get
Of pale yellow powder (E)¹Measurement of H-NMR spectrum
The results are shown below.¹ H-NMR (solvent: CDCl_Two, 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_TwoP, J = 16
Hz) δ (ppm) = 1.3 (t, 12H: ethoxy group) 1.4 g of the obtained phosphonate (E) (2.6 × 10
^-3Mol), 1.0 g of benzophenone (5.5 × 10^-3Guinea pig
0.6 g of potassium tert-butoxide (5.3 × 1
0^-3Mol) to 50 ml of dimethyl sulfoxide
Suspended. At room temperature under argon gas atmosphere
The mixture was stirred under reflux for 3 hours. After leaving overnight, methanol
50 ml was added, and the deposited precipitate was collected by filtration. Shi
Purification (developing solution: methylene chloride) using a Ricagel column
After that, the target fraction is acetone / n-hexane
The mixture was recrystallized to give 0.9 g of yellow powder (F).
Was obtained (yield: 37%). The melting point of this yellow powder (F) is
198-199 ° C. Of the obtained yellow powder (F)
¹The measurement results of the H-NMR spectrum are shown below. ¹ H-NMR (solvent: CDCl_Two, Standard: tetramethyl
Silane (TMS)) δ (ppm) = 6.7 to 8.2 (m, 34H: aromatic ring, quino
Xaline ring and -H of = C = HC) Also, as a result of mass spectrometry of the obtained yellow powder, m / Z = 6
Only 38 peaks were obtained, and (F) (DPVPQ)
It was confirmed that it was done.

Synthesis Example 9 Compounds shown in Table 1 were 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), 100n of ITO by evaporation method
A film having a thickness of m (made by HOYA, corresponding to an anode) was used as a transparent support substrate. The substrate was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol and further for 5 minutes in pure water, and then dried by blowing nitrogen thereto.
V300, manufactured by Samco International Laboratories)
Was performed at a substrate temperature of 150 ° C. for 20 minutes. On this transparent support substrate, a substrate holder of a commercially available vacuum evaporation apparatus (manufactured by Japan Vacuum Engineering Co., Ltd.) was fixed, and 200 mg of Cu-coordinated phthalocyanine (hereinafter abbreviated as CuPc) was placed in a molybdenum resistance heating boat. To another molybdenum resistance heating boat, N′-bis (3-methylphenyl) -N, N′-diphenyl (1,1′-biphenyl) -4,4′-diamine (hereinafter abbreviated as TPD (p)) ), And 4,4'-bis (2,2-diphenylvinyl) biphenyl (hereinafter abbreviated as DPVBi) in another molybdenum resistance heating boat.
mg, and the pressure in the vacuum chamber was reduced to 1 × 10 −4 Pa.
Thereafter, the boat containing CuPc was heated to about 350 ° C., and CuPc was deposited on the ITO film at a deposition rate of 0.1 to 0.3 nm / sec to form a 20-nm-thick CuPc layer. At this time, the temperature of the substrate was room temperature. Without taking this out of the vacuum chamber, the boat containing the TPD (p) was heated to about 250 ° C., and the deposition rate was 0.1 to 0.3 n.
TPD (p) was vapor-deposited on the CuPc layer at m / sec to provide a TPD (p) layer having a thickness of 40 nm. At this time, the substrate temperature was room temperature. The two layers of the CuPc layer and the TPD (p) layer thus provided correspond to a hole transport layer. Next, heat the boat containing DPVBi to about 240 ° C,
DP is deposited on the TPD (p) layer at a deposition rate of 0.1 to 0.3 nm / sec.
VBi was deposited by vapor deposition to provide a light emitting layer with a thickness of 40 nm. Next, the transparent support substrate on which the three organic layers were formed was taken out of the vacuum layer, and a stainless steel mask was placed on the light-emitting layer and fixed again to the substrate holder. In addition, a molybdenum resistance heating boat was used to prepare the 2,3-bis (2,2-diphenylvinyl) quinoxaline (hereinafter, referred to as “synthesis”) obtained in Synthesis Example 1.
Abbreviated as DPVQ. ) Was placed in a vacuum chamber. Next, a molybdenum resistance heating boat containing 1 g of magnesium ribbon and a tungsten basket containing 500 mg of silver wire were attached to the vacuum chamber. afterwards,
The pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. After decompression, DPV
Energize the boat with Q and heat it to 216 ° C,
The above light emitting layer was deposited at a deposition rate of 0.1 to 0.3 nm / sec.
An electron injection transport layer having a thickness of 20 nm was provided. Then, silver is deposited at a deposition rate of 0.1 nm / sec by supplying electricity to a tungsten basket containing silver wires, and at the same time, a deposition rate of 1.4 to 2.
Magnesium was deposited at 0 nm / sec. By this dual simultaneous vapor deposition, a 200 nm-thick magnesium-silver layer (corresponding to a cathode) was formed on the DPVQ layer. 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 flowed, and blue light emission with a high luminance of 60 cd / m ² was observed. At this time, the luminous efficiency is
It was 0.5 lumen / W. From the measurement result of the fluorescence spectrum, the emission peak wavelength was 474 nm, and D
Light emission from PVBi was confirmed. This element is 100c
The light was emitted at a luminance of d / m ² and observed using a luminance meter (CS-100, manufactured by Minolta Camera Co., Ltd.). There was no non-light-emitting region or uneven light emission as described above).

Examples 2 to 8 Instead of the DPVQ used as the electron injecting and transporting layer, the second
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the compounds shown in the table were used and the temperature of the heating boat at the time of vapor deposition was changed as shown in Table 2. Table 2 shows the obtained results.

COMPARATIVE EXAMPLE 1 Instead of DPVQ used as an electron injecting and transporting layer, a second
An organic EL device was prepared and evaluated in the same manner as in Example 1 except that the compounds shown in the table were used and the temperature of the heating boat at the time of vapor deposition was changed as shown in Table 2. Table 2 shows the obtained results.

Comparative Example 2 An organic EL device was manufactured and evaluated in the same manner as in Example 1 except that a cathode was directly attached to DPVBi as a light emitting material without using an electron injection / transport layer. Table 2 shows the obtained results.

[0082]

[Table 4]

* Evaluation of uniformity ：: Uniform light emission was observed in the observation region immediately after the device was manufactured or after one day. Δ: Uniform light emission was observed in the observation region immediately after the device was manufactured, but after one day, there was a non-light-emitting region with a diameter of 10 μm or less or uneven light emission. ×: The observation region has a non-light emitting region having a diameter of 10 μm or less or uneven light emission even immediately after the device is manufactured, even after one day.

As shown in Comparative Example 1, the one using SQ as the electron injecting / transporting layer has good adhesion of the cathode metal, but is inferior in the thin film property of the SQ itself, and thus crystallizes with time. As a result, the uniformity of light emission is poor. Further, as is apparent from Comparative Example 2, the element in which the cathode metal was directly provided on the light emitting material DPVBi had good thin film properties of the light emitting material, but had very poor adhesion of the metal, so that uniformity of light emission was obtained. Is inferior to

[0085]

[0086]

As described above, the present invention provides
By using a heterocyclic-containing styryl compound, it is possible to obtain an organic EL device having excellent properties of adhesion to a metal and thin film properties and excellent uniformity of light emission . Therefore, the organic EL element of the present invention is expected to be effectively used as various elements such as an organic EL element.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-103571 (JP, A) JP-A-2-252793 (JP, A) JP-A-4-103688 (JP, A) JP-A-3-103 33184 (JP, A) JP-A-3-231970 (JP, A) JP-A-2-247278 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09K 11/06 CA ( STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A positive electrode and the organic compound for the electron injecting and transporting Keru <br/> Contact to the electroluminescent element formed with an organic compound one or more layers sandwiched between the cathode, the general formula (I) [ Formula 1 (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 heterocyclic ring, or a saturated or unsaturated heterocyclic ring, Ar ¹ and Ar ^{2 each} 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 means 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. . These substituents may be the same or different, and the substituents may be combined with each other to form a saturated or unsaturated 5- or 6-membered ring. Ar ³ is a substituted or unsubstituted C 6-20 carbon atom
May be an arylene group or a single bond. ) A heterocyclic-containing styryl compound represented by the formula:
object. 2. The organic electroluminescent device according to claim 1, wherein the compound represented by the general formula (I) is used as a component of the electron injecting and transporting layer.