JP2003157978A - Organic electroluminescence device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescence device using fluorochrome with low driving voltage, solidity, and excellent light emitting efficiency. SOLUTION: For the organic electroluminescence device having a substrate on which, an organic layer and a negative electrode are sequentially laminated, the organic layer contains chromone group compound shown by formula (1). In the formula, R<1> -R<4> represent hydrogen atom, alkyl group, alkoxyl group, or the like, Y represents oxygen atom, or the like, Z represents direct bond, aromatic heterocycle, or the like, and n represents 0 or 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device using a specific compound useful as a fluorescent dye, and more particularly to a thin film type device that emits light by applying an electric field to an organic light emitting layer. Is.

[0002]

2. Description of the Related Art Conventionally, fluorescent dyes have been used for coloring various materials such as resins, dyes, inks, etc., but in recent years, by utilizing their fluorescent efficiency, they are used in the field of electronic devices such as thin film light emitting devices. Is being developed. Regarding fluorescent dyes, dyes having various structures and emission colors are known, but few compounds emit light with high efficiency and have excellent fastness.

4- (dicyanomethylene) -2-methyl-
It is widely known that a 6- (p-dimethylaminostyryl) -4H-pyran (hereinafter referred to as DCM) compound is used as a luminescent dye of an organic electroluminescence device (organic EL device). For example, U.S. Pat.No. 4,769,292 describes an example in which orange luminescence is obtained by using a DCM compound (DCM) having a structure represented by the following formula, and a DCM compound having a julolidine structure represented by the following formula ( An example in which red emission was obtained using DCJ) is disclosed.

[0004]

[Chemical 2]

[0005]

[Chemical 3]

Further, Japanese Patent Laid-Open No. 10-308281 discloses an example in which red fluorescence is obtained by using the following DCM compound (DCJTB).

[0007]

[Chemical 4]

Further, examples used as a luminescent dye of an organic electroluminescence device include rubrene exhibiting yellow fluorescence (JP-A-4-335087) and quinacridone exhibiting green fluorescence (US Pat. No. 5,593,788). Is widely known.

[0009]

[Chemical 5]

[0010]

[Chemical 6]

Japanese Patent Laid-Open No. 2001-115154 discloses that
For example, a fluorescent dye represented by the following formula is described, and it is described that it can be used in an organic electroluminescence device.

[0012]

[Chemical 7]

However, according to the results of our research, many compounds, such as the above-mentioned compounds, in which a chromone skeleton and an amino-substituted phenyl group are bonded by an ethylene group have weak fluorescence intensity in a solution. JP 2001-167833 A discloses the following general formula

[0014]

[Chemical 8]

An organic electroluminescent device using a compound represented by the following is described. In the invention described in the publication, luminance is improved by connecting a chromone skeleton and a benzene ring bonded thereto with a ring structure which is not aromatic to form a rigid molecular structure. In addition, JP-A-7-133
No. 482, for example, the following compound having a chromone skeleton:

[0016]

[Chemical 9]

An organic electroluminescent device using is described. However, in the case of this compound, since the ring bonded to the benzene ring bonded to the chromone skeleton is an aromatic ring, the electron donating property is low and the donor-acceptor effect in the molecule is weak. An organic EL element is required to emit light with high efficiency at a low voltage as represented by a portable small information terminal which is one of its applications. The light emitting device cannot obtain sufficient luminous efficiency, and further improvement in luminous efficiency is required. We have
Regarding these compounds, by fixing the molecular structure in a planar arrangement, it is possible to form an intramolecular structure and a donor-acceptor structure by bonding an amino group to the p-position of the phenyl group bonded to the chromone skeleton. Attention was paid to the improvement of luminous efficiency. Further, by connecting the chromone skeleton and the benzene ring with various connecting groups, for example,
It has been found that a compound that emits strong fluorescence can be obtained as compared with a compound bonded with an ethylene group, and that a compound that exhibits various emission colors in a wide wavelength range from blue to red can be easily obtained.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic electroluminescent device using a specific fluorescent dye, which has a low driving voltage and is excellent in characteristics such as robustness and luminous efficiency. .

[0019]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies based on the findings obtained previously, and found that a compound having a specific structure in which a nitrogen-substituted phenyl group is bonded is a fluorescent compound having excellent performance. The present invention has been accomplished by knowing that it is a dye. That is, the present invention is an organic electroluminescent device in which an anode, an organic layer, and a cathode are sequentially laminated on a substrate, wherein the organic layer contains a compound represented by the following general formula (I). The subject is an organic electroluminescent device that does.

[0020]

[Chemical 10]

(Where R¹~ R^FourAre each independently a hydrogen atom,
Having an alkyl group which may have a substituent, having a substituent
Shows optional alkoxy groups, halogen atoms, and cyano groups.
And R ^Five~ R^TenHas a hydrogen atom or a substituent
Represents a good alkyl group.

R ⁸ and R ⁹ may be combined to form a ring, or R ⁷ and R ⁸ and R ⁹ and R ¹⁰ may be combined to form a ring. Y is an oxygen atom or CR ¹¹ R
^And R ¹¹ and R ¹² are cyano groups or —C (=
O) OR ¹³ (wherein R ¹³ represents an alkyl group which may have a substituent).

Z has a direct bond, a thiophene ring which may have a substituent, a furan ring which may have a substituent, a pyrrole ring which may have a substituent, or a substituent. Represents a benzene ring which may be present. n represents 0 or 1. )

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
First, the compound used in the present invention will be described. The compound used in the present invention has a structure represented by the general formula (I).

In the general formula (I), when R ^{1 to} R ⁴ represent an alkyl group which may have a substituent, examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-
Propyl group, n-butyl group, i-butyl group, sec-butyl group,
Examples thereof include linear or branched alkyl groups having about 1 to 8 carbon atoms such as t-butyl group, n-pentyl group and 2-ethylhexyl group. These alkyl groups may be substituted,
Examples of the substituent include a hydroxy group, an aryl group, an alkoxy group, a halogen atom and the like, and the total number of carbon atoms of the substituted alkyl group is 1 to 15, preferably 1 to 10.

When R ^{1 to} R ⁴ represent an alkoxy group, examples thereof include an alkoxy group having 1 to 8 carbon atoms such as methoxy group, ethoxy group, propoxy group and butoxy group. These alkoxy groups may be substituted, and examples of the substituent include a hydroxy group, an aryl group, an alkoxy group, a halogen atom and the like, and the substituted alkoxy group has a total carbon number of 1 to 15, preferably 1 to 10. , And more preferably 1 to 4
Is.

When R ^{1 to} R ⁴ represent a halogen atom, specific examples thereof include a chlorine atom, a bromine atom, a fluorine atom and an iodine atom. As R ^{1 to} R ⁴ , a hydrogen atom or an alkoxy group having 1 to 4 carbon atoms is preferable. R ^{5 to} R ¹⁰
When represents an alkyl group which may have a substituent, the alkyl group includes the same functional groups as those described as the alkyl group which may have a substituent of R ^{1 to} R ^4. .

Examples of the ring formed by combining R ⁷ and R ⁸ , R ⁸ and R ⁹ , and R ⁹ and R ¹⁰ include the following.

[0029]

[Chemical 11]

(In the formula, R ¹⁶ is an arbitrary substituent, preferably a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms. In the above structure, R ⁷ and R ⁸ and R are ⁸
And R ^9, R ⁹ and R ¹⁰ is formed by bonding ring, R ⁵ to R
^It may be substituted with the group described above as ¹⁰ . ) As described above, R ⁷ and R ⁸ , R ⁸ and R ⁹ and R ⁹ and R
^The ring formed by combining ¹⁰ is preferably not an aromatic ring, and particularly preferably a saturated ring.

As R ^{5 to} R ¹⁰ and R ¹⁶ , a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferable. In addition, R
^{As 7 to} R ¹⁰ , a 5- or 6-membered saturated ring formed by bonding adjacent groups is also preferable. Y is an oxygen atom or CR
¹¹ represents R ¹² , wherein R ¹¹ and R ¹² are a cyano group or —C
(═O) OR ¹³ (wherein R ¹³ is an alkyl group which may have a substituent). Examples of R ¹³ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-
Butyl group, sec-butyl group, t-butyl group, n-pentyl group,
Examples thereof include linear or branched alkyl groups having about 1 to 8 carbon atoms such as 2-ethylhexyl group. These alkyl groups may be substituted, and examples of the substituent include a hydroxy group, an aryl group, an alkoxy group, a halogen atom, etc., and the total number of carbon atoms of the substituted alkyl group is 1 to 15, preferably 1 to 10. Is. R ¹³ is preferably an alkyl group having 1 to 4 carbon atoms.

From the viewpoint of fluorescence intensity, Y is preferably an oxygen atom. This is because, when Y is an oxygen atom, steric repulsion between Y and a hydrogen atom on the adjacent benzene ring does not occur, and twist of the conjugated system does not occur, unlike CR ¹¹ R ^12. It is thought that. Z represents a direct bond, a thiophene ring, a furan ring, a pyrrole ring, or a benzene ring, and the thiophene ring, the furan ring, the pyrrole ring, and the benzene ring may have a substituent.

Examples of the substituent which the thiophene ring, furan ring, pyrrole ring and benzene ring may have include linear or branched alkyl groups having about 1 to 8 carbon atoms.

As Z, a thiophene ring, a furan ring and a pyrrole ring are more preferred. n is 0 or 1. Representative examples of such compounds of the present invention are shown in Table 1.
The compound of the present invention is not limited to these. In Table 1, Me is a methyl group, Et is an ethyl group, ip
r represents an isopropyl group.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

The compound represented by the general formula (I) in the present invention can be produced by a known method. For example, dimethyl sulfoxide and salicylic acid ester are reacted to obtain a methylsulfinylacetophenone derivative,
Then, a method of reacting with 4-diethylaminobenzaldehyde, julolidine, a formyl body or the like, or by reacting the obtained methylsulfinylacetophenone body with acetaldehyde to obtain 2-methylchromone,
Various methods such as a method of reacting with -diethylaminobenzaldehyde or 4-diethylaminobenzaldehyde are adopted. Next, the organic electroluminescent element of the present invention will be described.

The organic electroluminescent device of the present invention is characterized by having an organic layer between an anode and a cathode which face each other, and the organic layer contains a dye comprising a compound of the general formula (I). The “organic layer” in the present invention means a layer which is located between the anode and the cathode and which is substantially made of an organic material, and these layers may contain an inorganic material as long as the performance of the present invention is not impaired. Specifically, a hole transport layer, an electron transport layer, a light emitting layer, and the like described later correspond to the “organic layer”. FIG. 1 is a cross-sectional view schematically showing a structural example of a general organic electroluminescent device used in the present invention, wherein 1 is a substrate, 2 is an anode, 4 is a hole transport layer, 5 is an electron transport layer, and 7 Represent cathodes, respectively. As the organic layer containing the compound represented by the general formula (I),
There is no particular limitation, and for example, in the device having the structure shown in FIG. 1, either the hole transport layer 4 or the electron transport layer 5 may be used. Hereinafter, the element having the structure shown in FIG. 1 will be described as an example.

The substrate 1 serves as a support for the organic electroluminescence device, and a plate of quartz or glass, a metal plate or metal foil, a plastic film or sheet, etc. is used. In particular, a glass plate and a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. When using a synthetic resin substrate, it is necessary to pay attention to the gas barrier property. If the gas barrier property of the substrate is too low, the organic electroluminescent element may deteriorate due to the outside air passing through the substrate, which is not preferable. Therefore, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

An anode 2 is provided on the substrate 1, and the anode 2 plays a role of injecting holes into the hole transport layer. This anode is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or poly. (3-
Methylthiophene), polypyrrole, polyaniline, and other conductive polymers. The anode 2 is usually formed by a sputtering method, a vacuum vapor deposition method, or the like. In the case of fine particles of metal such as silver, fine particles of copper iodide, carbon black, fine particles of conductive metal oxide, fine particles of conductive polymer, etc., they are dispersed in an appropriate binder resin solution and then placed on the substrate 1. The anode 2 can also be formed by applying to Further, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or a conductive polymer can be applied on the substrate 1 to form the anode 2 (Appl. Phys. Lett. , Volume 60, pages 2711, 1
992). The anode 2 can also be formed by stacking different materials. The thickness of the anode 2 depends on the required transparency. If transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more, in this case, the thickness is usually 5 nm, preferably 10 nm, the lower limit, The upper limit is usually 1000 nm, preferably about 500 nm. If it may be opaque, the thickness of the anode 2 may be the same as that of the substrate 1. Further, it is also possible to stack different conductive materials on the anode 2.

A hole transport layer 4 is provided on the anode 2. The conditions required for the material of the hole transport layer are that the hole injection efficiency from the anode is high and that the injected holes can be efficiently transported. For that purpose, the ionization potential is low, the transparency to visible light is high, the hole mobility is high, the stability is excellent, and impurities that serve as traps are less likely to be generated during manufacturing or use. Required. Also,
It is necessary that the material does not contain a substance that quenches the light emission of the light emitting layer. In addition to the above general requirements, when considering application for in-vehicle display, the element is required to have further heat resistance.
Therefore, a material having a Tg value of 70 ° C. or higher is desirable.

Examples of such hole transport materials include 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane and 4,4′-bis [N- (1-naphthyl) -N- Phenylamino]
Contains two or more tertiary amines represented by biphenyl 2
Starburst structure of aromatic diamine in which one or more condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Laid-Open No.5-234681), 4,4 ', 4 "-tris (1-naphthylphenylamino) triphenylamine, etc. Aromatic amine compound having (J. Lumin.,
72-74, p. 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., 217).
5, p. 1996), an aromatic triamine having a starburst structure in a derivative of triphenylbenzene (US Pat.
4,923,774), N, N'-diphenyl-N, N'-bis (3-
A compound in which a plurality of aromatic diamino groups are substituted on a pyrenyl group, such as methylphenyl) biphenyl-4,4′-diamine, an aromatic diamine having a styryl structure (Japanese Patent Laid-Open No. 4-290851), and a thiophene group for aromatic 3 Primary amine unit linked (JP-A-4-304466), starburst type aromatic triamine (JP-A-4-308688), tertiary amine linked by fluorene group (JP-A-5-25473). Gazette), triamine compound (JP-A-5-239455), bisdipyridylaminobiphenyl, N, N, N-triphenylamine derivative (JP-A-6-1972), aromatic diamine having phenoxazine structure (special Kaihei 7138562),
Diaminophenylphenanthridine derivative (JP-A-7-25
2474), silazane compounds (US Pat. No. 4,950,950).
Specification), a silanamine derivative (JP-A-6-49079), a phosphamine derivative (JP-A-6-25659),
Spiro compounds such as 2,2 ', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, 91
Vol., P. 209, 1997). These compounds may be used alone, or may be used as a mixture if necessary.

In addition to the above compounds, the material of the hole transport layer 4 is polyvinylcarbazole or polysilane (Ap).
Pl. Phys. Lett., Vol. 59, p. 2760, 1991), polyphosphazene (JP-A 5-310949), polyamide (JP-A 5-310949), polyvinyltriphenylamine (JP-A 7- 53953), a polymer having a triphenylamine skeleton (JP-A-4-133065), and a polymer in which triphenylamine units are linked by a methylene group or the like (Synthetic Metals, 55-57, 4163, 1993). ), Polymethacrylate containing aromatic amine (J. Polym.
Sci., Polym. Chem. Ed., 21: 969, 1983). The hole transport layer 4 is formed by laminating the above hole transport material on the anode 2 by a coating method or a vacuum deposition method.

In the case of the coating method, one or more hole transport materials are added, and if necessary, an additive such as a binder resin or a coatability improving agent which does not trap holes,
The solution is dissolved to prepare a coating solution, which is coated on the anode 2 by a method such as a spin coating method and dried to form a hole transport layer. Examples of the binder resin include polycarbonate, polyarylate, polyester and the like. If the addition amount of the binder resin is large, the hole mobility is lowered. Therefore, the binder resin is preferably added in a small amount.

In the case of the vacuum deposition method, the hole transport material is put in a crucible installed in a vacuum vessel, the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa by an appropriate vacuum pump, and then the crucible is heated. Then, the hole transport material is evaporated, and the hole transport layer 4 is placed on the substrate 1 on which the anode is formed, which is placed facing the crucible.
To form. The lower limit of the thickness of the hole transport layer 4 is usually 10
nm, preferably 30 nm, and the upper limit is usually 300 n
m, preferably 100 nm. In order to uniformly form such a thin film, the vacuum evaporation method is often used.

An electron transport layer 5 is provided on the hole transport layer 4. The electron transporting material used for the electron transporting layer 5 is required to have high electron injection efficiency from the cathode 7 and to be able to efficiently transport the injected electrons toward the hole transporting layer 4. For that purpose, it is required that the compound has a high electron affinity, a high electron mobility, excellent stability, and an impurity that becomes a trap and is hard to be generated during the production or the use.

As a material satisfying such a condition, an aromatic compound such as tetraphenyl butadiene (see JP-A-57 / 57)
-51781), a metal complex such as an aluminum complex of 8-hydroxyquinoline (JP-A-59-194393), a metal complex of 10-hydroxybenzo [h] quinoline (JP-A-6-32236).
2), mixed-ligand aluminum chelate complexes (Japanese Patent Laid-Open No. 5-198377, Japanese Patent Laid-Open No. 5-198378, Japanese Patent Laid-Open No. 5-198378).
No. 214332, JP-A-6-172751), cyclopentadiene derivative (JP-A-2-289675), perinone derivative (JP-A-2-289676), oxadiazole derivative (JP-A-2-216791). ), Bisstyrylbenzene derivatives (JP-A 1-245087 and JP-A 2-222484), perylene derivatives (JP-A 2-189890 and JP-A 3-791), and coumarin compounds (JP-A-2- Japanese Patent No. 191694
3-792), rare earth complexes (JP-A-1-256584), distyrylpyrazine derivatives (JP-A-2-252793), p-phenylene compounds (JP-A-3-33183),
Thiadiazolopyridine derivative (JP-A-3-37292), pyrrolopyridine derivative (JP-A-3-37293), naphthyridine derivative (JP-A-3-203982),
Bisstyrylarylene derivatives (JP-A-2-247278), metal complexes of (2-hydroxyphenyl) benzothiazole (JP-A-8-315983), silole derivatives (Chemical Society of Japan 70th Spring Annual Meeting, 2D102 and 2D1 03, 1996) etc.

The lower limit of the thickness of the electron transport layer 5 is usually 10 n.
m, preferably 30 nm, and the upper limit is usually 200 n
m, preferably 100 nm. The electron transport layer can be formed by the same method as the hole transport layer, but a vacuum deposition method is usually used. The compound represented by the general formula (I) may be doped in the hole transport layer 4 and / or the electron transport layer 5 to emit light. Further, a light emitting layer may be separately formed between the hole transporting layer 4 and the electron transporting layer 5, and the compound represented by the general formula (I) may be contained in the light emitting layer. When the hole-transporting layer 4 and / or the electron-transporting layer 5 is doped to emit light, for example, when the electron-transporting layer 5 is doped, the above-mentioned electron-transporting material serves as a host material,
When the hole transport layer 4 is doped, the hole transport material described above acts as a host material.

When the charge transporting polymer material is doped to emit light, for example, the above-mentioned polymer material as the hole transporting material is doped with the compound represented by the general formula (I). Alternatively, the above-mentioned electron transporting compound may be contained in combination with the compound. When another light emitting layer is provided between the hole transporting layer 4 and the electron transporting layer 5, the light emitting layer is:
It may be a layer containing the compound represented by the general formula (I) as a main component, or may be a layer containing a specific host material as a main component and represented by the general formula (I) with respect to the host material. It may be a layer doped with a compound. It is preferable that the host material in the light emitting layer is a compound that has both a charge transporting property and a light emitting property to some extent, is excellent in stability, and is unlikely to generate impurities serving as traps during production or use. Specifically, the hole transport material and the electron transport material may be selected from those described above, or may be appropriately selected from known light emitting layer host materials. In addition, two or more kinds of the compounds represented by the general formula (I) may be used in combination, and other fluorescent dyes may be used in combination as long as the performance of the present invention is not impaired. In this case, the compound represented by the general formula (I) can be used as a host material and another fluorescent dye can be used as a dopant. 16
As described in Japanese Patent No. 4362, it can also be used as a dopant for exciting energy transfer that assists the emission of other dopants. Examples of other fluorescent dyes that may be used in combination include perylene compound derivatives, pyrene compound derivatives, anthracene compound derivatives, coumarin compound derivatives, quinacridone compound derivatives, and naphthalic acid compound derivatives. The compound represented by the general formula (I) preferably has a form in which the main component in the layer containing the compound is a host material and the host material is doped.

The region doped with the compound represented by the general formula (I) may be the entire layer containing the compound or a part thereof, and is uniformly distributed in the thickness direction of the layer. It may be doped or may have a concentration distribution in the film thickness direction. For example, the electron transport layer 5 may be doped only near the interface with the hole transport layer 4, or conversely, may be doped near the cathode interface. The amount of the compound represented by the general formula (I) to be doped is based on the host material.
10 ⁻³ to 10% by weight is preferable, and 0.1 to 10% by weight is more preferable.

When the host material is doped with the compound represented by the general formula (I), the luminous efficiency of the device is improved. Further, this compound has a characteristic that the emission wavelength changes depending on the doped host material.
o. The emission wavelength of the chromone-based compound of 14 changes from green to yellow.

Doping of the compound represented by the general formula (I) into the electron transport layer 5 and / or the hole transport layer 4 is as follows.
It is performed at the time of forming the layer by a coating method or a vacuum deposition method according to the method for forming the layer serving as a host. Further, when the light emitting layer provided between the hole transporting layer 4 and the electron transporting layer 5 is doped with the compound represented by the general formula (I), depending on the properties of the host material of the layer, The layers can be formed according to the description. In the case of coating, for example, an electron transporting material (host material), a compound represented by the general formula (I), and, if necessary, a binder resin that does not become an electron trap or a quencher for light emission, and a leveling agent An additive such as a property improving agent is added and dissolved to prepare a coating solution, which is coated on the hole transport layer 4 by a method such as a spin coating method,
The electron transport layer 5 is formed by drying. Examples of the binder resin include polycarbonate, polyarylate, polyester and the like. The addition amount of the binder resin decreases the hole / electron mobility when it is added in a large amount.

In the case of the vacuum vapor deposition method, for example, the electron transport material is placed in a crucible placed in a vacuum vessel, the compound represented by the general formula (I) is placed in another crucible, and the inside of the vacuum vessel is placed. After evacuating to about 10 ⁻⁴ Pa with a suitable vacuum pump, each crucible is simultaneously heated and evaporated to form a layer on the substrate placed facing the crucible. As another method, a mixture of the above materials in a predetermined ratio may be evaporated using the same crucible. Hole transport layer 4
The same applies to the case of doping the light emitting layer.

The cathode 7 plays a role of injecting electrons into the electron transport layer 5. The material used for the cathode 7 may be the material used for the anode 2, but a metal having a low work function is preferable for efficient electron injection, and tin, magnesium, indium, calcium,
Suitable metals such as aluminum and silver or alloys thereof are used. As a specific example, a magnesium-silver alloy,
Examples include low work function alloy electrodes such as magnesium-indium alloy and aluminum-lithium alloy. further,
Providing an extremely thin insulating film (0.1 to 5 nm) of LiF, MgF ₂ , Li ₂ O or the like on the interface of the cathode on the organic layer side is also an effective method for improving the efficiency of the device (Appl. Phys. Lett. , 70
Volume, p. 152, 1997; JP-A-10-74586; IEEE Tran
S. Electron. Devices, 44, 1245, 1997). The film thickness of the cathode 7 is usually the same as that of the anode 2. For the purpose of protecting the cathode made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere on the cathode in order to increase the stability of the device. For this purpose,
Metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used.

In the device having the structure shown in FIG. 1, the hole transport layer 4 has a function of receiving holes from the anode 2 (hole injection) and a function of transporting the received holes to the electron transport layer 5 (hole transport). As a result, the electron transport layer 5 also has a function of transporting the electrons received from the cathode 7 to the hole transport layer 4 (electron transport).
However, in order to further improve the emission characteristics and driving stability of the device of the present invention, an electron injection layer 6 may be provided between the electron transport layer 5 and the cathode 7 as shown in FIG. 2, or shown in FIG. As described above, the anode buffer layer 3 may be provided between the anode 2 and the hole transport layer 4, and the structure may be divided into layers for each function, that is, a function-separated device.

As shown in FIGS. 2 and 3, by providing the electron injection layer 6 between the electron transport layer 5 and the cathode 7, it is possible to further improve the luminous efficiency of the device. The material used for the electron injection layer 6 is required to be capable of easily injecting electrons from the cathode and further having an electron transporting ability. As such an electron injection material, an aluminum complex of 8-hydroxyquinoline, an oxadiazole derivative (Appl. Phys. Lett., 55
Vol., P. 1489, 1989, etc.) and systems in which they are dispersed in a resin such as polymethylmethacrylate (PMMA) (Appl. Phys. Le
tt., 61, 2793, 1992), phenanthroline derivative (JP-A-5-331459), 2-t-butyl 9,10-N, N'-dicyanoanthraquinonediimine (Phys. Stat. Sol.
(a), Vol. 142, p. 489, 1994), n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide and the like.

The lower limit of the thickness of the electron injection layer 6 is usually 5 n.
m, preferably 10 nm, and the upper limit is usually 200 n
m, preferably 100 nm. Further, the anode buffer layer 3 may be inserted between the hole transport layer 4 and the anode 2 for the purpose of further improving the efficiency of hole injection and improving the adhesion of the entire organic layer to the anode. It is being done (Figure 3). By inserting the anode buffer layer 3, the driving voltage of the element in the initial stage is lowered, and at the same time, the voltage rise when the element is continuously driven with a constant current is suppressed. The conditions required for the material used for the anode buffer layer are good contact with the anode and a uniform thin film can be formed.
It is thermally stable, that is, it has a high melting point and a high glass transition temperature. The melting point is preferably 300 ° C or higher, and the glass transition temperature is preferably 100 ° C or higher. Further, it has a low ionization potential, easy hole injection from the anode, and high hole mobility.

For this purpose, porphyrin derivatives, phthalocyanine compounds (JP-A-63-295695), hydrazone compounds, alkoxy-substituted aromatic diamine derivatives, p- (9-anthryl) -N, N have hitherto been used. '-Di-p-tolylaniline, polythienylene vinylene, poly-p-phenylene vinylene, polyaniline (Appl. Phys. Lett., 64, 1
245, 1994), polythiophene (Optical Materials,
Vol. 9, p. 125, 1998), organic compounds such as star bust type aromatic triamine (JP-A-4-308688), sputtered carbon film (Synth. Met., Vol. 91, p. 73, 1997).
Year) and metal oxides such as vanadium oxide, ruthenium oxide and molybdenum oxide (J. Phys. D, Vol. 29, 2750
Page, 1996).

Examples of the low molecular weight compound which is often used as the material for the anode buffer layer include a porphine compound and a phthalocyanine compound. These compounds may have a central metal or may be metal-free. Specific examples of preferred compounds include the following compounds: Porphine 5,10,15,20-tetraphenyl-21H, 23H-porphine 5,10,15,20-Tetraphenyl-21H, 23H-porphine Cobalt (II) 5,10,15,20-Tetraphenyl-21H, 23H-porphine copper (I
I) 5,10,15,20-Tetraphenyl-21H, 23H-porphine zinc (II) 5,10,15,20-Tetraphenyl-21H, 23H-porphine vanadium (IV) oxide 5,10,15,20 -Tetra (4-pyridyl) -21H, 23H-porphine 29H, 31H-phthalocyanine copper (II) phthalocyanine zinc (II) phthalocyanine titanium phthalocyanine oxide magnesium phthalocyanine lead phthalocyanine copper (II) 4,4 ', 4'',4''' -Tetraaza-29H, 31H-phthalocyanine

The polymer compound that can be used as the material for the anode buffer layer is, for example, Japanese Patent Laid-Open No. 9-1887.
No. 56, JP 11-135262, WO 97/33193 JP, JP 10-92584 JP, JP 11-283750 JP,
Examples thereof include, but are not limited to, a polymer compound or a combination of a polymer compound and an electron-accepting compound described in JP-A-2000-36390 and JP-A-2000-150168. Also in the case of the anode buffer layer, a thin film can be formed in the same manner as the hole transport layer in the case of the low molecular weight compound, but in the case of the inorganic material, the sputtering method, the electron beam evaporation method or the plasma CVD method is further used. To be

In the case of a high molecular compound, a thin film can be formed by a usual coating method such as a spray method, a printing method, a spin coating method, a dip coating method, a die coating method or an ink jet method. Alternatively, a thin film may be formed in advance on a medium such as a film, a substrate or a roll by the thin film forming method described above, and the thin film on the medium may be thermally or pressure transferred to form the thin film. The lower limit of the thickness of the anode buffer layer 3 formed as described above is usually 3 nm, preferably 10 nm,
The upper limit is usually 100 nm, preferably 50 nm.

By providing the hole blocking layer in contact with the cathode side interface of the layer doped with the compound represented by the general formula (I), the luminous efficiency of the device can be further improved. . The hole blocking layer has a role of blocking the holes moving from the hole transporting layer from reaching the cathode, and a compound capable of efficiently transporting the electrons injected from the electron injecting layer toward the light emitting layer. Formed by. Further, in order to confine excitons generated by recombination in the light emitting layer in the light emitting layer, it is necessary to have a bandgap wider than that of the light emitting layer material. The bandgap in this case is
It is determined from the difference between the oxidation potential and the reduction potential, which is electrochemically determined, or the light absorption edge. The hole blocking layer has a function of confining both charge carriers and excitons in the light emitting layer to improve the light emission efficiency.

As a hole blocking layer material satisfying these conditions, bis (2-methyl-8-quinolinolato) (phenolato) is used.
Aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum and other mixed ligand complexes,
Bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum Metal complexes such as dinuclear metal complexes and styryl compounds such as distyrylbiphenyl derivatives (JP-A-11- 242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-
Triazole derivatives such as triazole (JP-A-7-41759)
), And phenanthroline derivatives such as bathocuproine (JP-A-10-79297).

It is also possible to stack the cathode 7, the electron transport layer 5, the hole transport layer 4, and the anode 2 in this order on the substrate, which is the reverse of the structure shown in FIG. It is also possible to provide the organic electroluminescent element of the present invention between two substrates, one of which is highly transparent. Similarly, it is also possible to stack in a structure opposite to the above-mentioned layer structure shown in FIGS. 2 and 3.

The present invention can be applied to any of a single element, an element having an arrayed structure, and a structure in which an anode and a cathode are arranged in an XY matrix. You can According to the organic electroluminescent device of the present invention, since the organic layer contains the compound represented by the general formula (1), the driving voltage is low, and the blue or red organic electric field is excellent in luminous efficiency and device stability. Luminescence is obtained.

[0067]

EXAMPLES Hereinafter, a method for synthesizing the compound represented by the general formula (I) and an organic electroluminescent device using the compound will be described more specifically with reference to Examples and Test Examples. The invention is not limited to these as long as the gist thereof is not exceeded. Example 1

[0068]

[Chemical 12]

Dimethyl sulfoxide 21.7 ml and toluene 4
2.41 g of 60% sodium hydride was added to 8.2 ml, and the mixture was reacted at 80 ° C for 1 hour. After cooling to 35 ° C., a solution of ethyl salicylate (2 g) in toluene (24 ml) was added dropwise. The mixture was cooled to room temperature over about 2 hours, and toluene was concentrated and removed. The reaction solution was added to ice water, pH was adjusted with acetic acid, extraction was performed with ethyl acetate, the organic layer was washed with water, dried and concentrated to obtain 1.9 g of pale yellow crystals. NMR,
As a result of MS analysis, 2'-hydroxy-2, which is an intermediate, was obtained.
It was confirmed to be-(methylsulfinyl) acetophenone.

A drop of piperidine was added to a solution of 0.2 g of this intermediate in 6.4 ml of toluene, and the mixture was heated to 50 ° C. 4 in this reaction solution
-Diethylaminobenzaldehyde (0.36 g) was added, and the mixture was heated under reflux for 3 hours. After completion of the reaction, the solvent was concentrated and removed, and purification by column chromatography was performed to obtain 0.16 g of yellow crystals. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 1.

M / e: 293 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.23 (t, 6H), 3.45 (q, 4H),
6.69 (s, 1H), 6.73 (d, 2H), 7.39 (t, 1H), 7.54 (d, 1H), 7.62
(t, 1H), 7.80 (d, 2H) 8.21 (d, 1H) Absorption spectrum: λmax 338 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 450 nm (excitation wavelength 254 nm, solvent: methylene chloride) Example 2

[0072]

[Chemical 13]

0.1 g of the compound obtained in Example 1 acetic anhydride
The 4 ml solution was heated to 40 ° C., 0.041 g of malononitrile was added, and the temperature was further raised to 95 ° C. and reacted for 3 hours. The solvent was distilled off, purification by column chromatography was performed, and 63 mg
Yellow crystals were obtained.

The analysis results of the obtained solid are as follows. It was confirmed that the compound had a structure of 3. m / e: 341 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.25 (t, 6H), 3.46 (q, 4H),
6.73 (d, 2H), 7.18 (s, 1H), 7.41 (t, 1H), 7.52 (d, 1H), 7.69
(t, 1H), 7.84 (d, 2H), 8.96 (d, 1H) Absorption spectrum: λmax 483 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 557 nm (excitation wavelength: 366 nm solvent: methylene chloride) Example 3

[0075]

[Chemical 14]

According to the method of Example 1, except that methyl 4-methoxysalicylate was used as the starting material for the reaction,
The reaction of the above formula was performed to obtain 0.81 g of a solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 6. m / e: 323 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.22 (t, 6H), 3.44 (q, 4
H), 3.93 (s, 3H), 6.63 (s, 1H), 6.72 (d, 2H), 6.94 (s, 1H), 6.9
5 (d, 1H), 7.78 (d, 2H), 8.12 (d, 1H) absorption spectrum: λmax 380 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 444 nm (excitation wavelength 366 nm solvent: methylene chloride) Example 4

[0077]

[Chemical 15]

0.5 g of the compound obtained in Example 3 was subjected to the reaction of the above formula according to the method of Example 2 to obtain 0.26 g of a solid. The analysis results of the obtained solid are as follows.
No. 1 It was confirmed that the compound had a structure of 7. m / e: 371 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.24 (t, 6H), 3.46 (q, 4
H), 3.96 (s, 3H), 6.70 (d, 2H), 6.95 (s, 1H), 7.00 (d, 1H), 7.1
1 (s, 1H), 7.82 (d, 2H), 8.87 (d, 1H) Absorption spectrum: λmax 472 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 547 nm (excitation wavelength: 366 nm solvent: methylene chloride) Example 5

[0079]

[Chemical 16]

Using the intermediate methylsulfinylacetophenone derivative of Example 1 and the formyl derivative of julolidine in place of 4-diethylaminobenzaldehyde, the reaction of the above formula was carried out according to the method of Example 1 to give 0.11 g.
To give a solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 9. m / e: 317 ¹ H-NMR (CDCl ₃ (δ = ppm)): 2.00 (m, 2H), 2.80 (t, 2)
H), 3.28 (t, 2H), 6.63 (s, 1H), 7.30 ~ 7.65 (m, 5H), 8.20 (d, 1
H) Absorption spectrum: λmax 401 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 481 nm (excitation wavelength 366 nm, solvent: methylene chloride) Example 6

[0081]

[Chemical 17]

The reaction of the above formula was carried out according to the method of Example 2 using 0.05 g of the compound obtained in Example 5 to obtain 11 mg of a solid. The analysis results of the obtained solid are as follows,
No. 1 in Table-1. It was confirmed that the compound had a structure of 11. m / e: 365 Absorption spectrum: λmax 506 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 595 nm (excitation wavelength: 366 nm solvent: methylene chloride) Reference Example 1 Hereinafter, the intermediates used in Examples were synthesized according to the following formula. .

[0083]

[Chemical 18]

To a solution of 4.86 g of 4-cyanophenol in 31 ml of trifluoroacetic acid, 11.44 g of hexamethylenetetramine was slowly added. After completion of the addition, heating reflux was carried out for 29 hours. After the reaction was completed, a sulfuric acid aqueous solution was added and the mixture was extracted with ethyl acetate. The organic layer was washed twice with 1N hydrochloric acid water and twice with water, and concentrated. The obtained crude product was purified by column chromatography to obtain 1.466 g of white crystals. Obtained crystal 1.28
0.7 ml of 60% perchloric acid was added to a 59 ml solution of 6 g of methanol, and a solution of 0.0854 g of vanadium pentoxide dissolved in 4.76 ml of 30% aqueous hydrogen peroxide was added dropwise under ice cooling. After completion of dropping, the reaction was continued for 1.5 hours. After completion of the reaction, water was added and the precipitated white crystals were filtered out to obtain 0.78 g. It was confirmed that this crystal was a methyl ester which was an intermediate.

Toluene 7.5 to 0.564 g of 60% sodium hydride
ml, add dimethyl sulfoxide 5 ml toluene 12.5 ml
The solution was added dropwise. The reaction was carried out at 80 ° C for 1 hour. After reaction, about
After cooling to 35 ° C, a solution of 0.5 g of the methyl ester obtained above in 7.5 ml of toluene was added dropwise, and the mixture was further reacted at 40 ° C for 2 hours. After completion of the reaction, water was added, acidified with acetic acid, and extracted with ethyl acetate. The organic layer was washed with water and concentrated to give 1.08 g of pale yellow crystals.

Example 7

[0087]

[Chemical 19]

Using 0.02 g of the compound obtained in Reference Example-1 and following the method of Example 1 and subsequently Example 2 except that the formyl form of julolidine is used instead of 4-diethylaminobenzaldehyde, the reaction of the above formula Was performed to obtain about 10 mg of solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 12. m / e: 390 Absorption spectrum: λmax 532 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 619 nm (excitation wavelength 532 nm, solvent: methylene chloride) Reference Example 2

[0089]

[Chemical 20]

According to the above formula, intermediates used in the following examples were synthesized. To 5.0 g of N, N-diethyl-p-phenyldiamine hydrochloride was added 4.58 ml of concentrated hydrochloric acid and 8.75 ml of water, and the mixture was cooled with ice.
An aqueous solution of 1.82 g of sodium nitrite was slowly added dropwise. After stirring for about 30 minutes, a solution of 2.8 g of thiophene aldehyde in 15 ml of acetone was added dropwise. After the dropping was completed, the temperature was slowly raised to room temperature, and a solution of 0.68 g of copper (II) chloride in 5 ml of water was added,
The reaction was carried out at 50 ° C for 4 hours.

After completion of the reaction, the reaction mixture was extracted with ethyl acetate, the organic layer was washed with aqueous sodium carbonate solution and concentrated. The resulting crude product was purified by column chromatography, 0.
11 g of solid was obtained. The analysis results of the obtained solid are as follows, and it could be confirmed that the compound was the target compound of the above formula.

M / e: 259 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.22 (t, 6H), 3.40 (q, 4H),
6.67 (d, 2H), 7.22 (d, 1H), 7.54 (d, 2H), 7,67 (d, 1H), 9.81
(s, 1H) absorption spectrum: λmax 413 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 518 nm (excitation wavelength 366 nm solvent: methylene chloride) Reference Example 3

[0093]

[Chemical 21]

According to the above formula, intermediates used in the following examples were synthesized. The reaction of the above formula was performed according to the method shown in Reference Example 2 except that furanaldehyde was used instead of thiophene aldehyde to obtain 0.85 g of a solid.

The analysis results of the obtained solid are as follows, and it was confirmed that the target compound of the above formula was obtained. m / e: 243 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.20 (t, 6H), 3.40 (q, 4H),
6.59 (d, 1H), 6.67 (d, 2H), 7.28 (d, 1H), 7,68 (d, 2H), 9.51
(s, 1H) Absorption spectrum: λmax 398 nm (solvent: methylene chloride) Fluorescence spectrum: λmax 494 nm (excitation wavelength: 398 nm solvent: methylene chloride) Example 8

[0096]

[Chemical formula 22]

One drop of piperidine was added to a solution of 0.023 g of 2'-hydroxy-2- (methylsulphenyl) acetophenone in 0.8 ml of toluene, and the mixture was heated to 50 ° C. To this solution was added 0.06 g of the formyl body obtained in Reference Example-2, and the mixture was heated under reflux for 3 hours. After completion of the reaction, the solvent was distilled off and the residue was purified by column chromatography to obtain 0.026 g of solid. The analysis results of the obtained solid are as follows, and
o. It was confirmed that the compound had a structure of 14. m / e: 375 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.20 (t, 6H), 3.40 (q, 4H),
6.40 (s, 1H), 6.68 (d, 2H), 7.18 (d, 1H), 7.39 (t, 1H), 7.51
(d, 1H), 7,52 (d, 2H), 7.65 (d, 1H), 7.66 (t, 1H), 8.21 (d, 1H) Absorption spectrum: λmax 433nm (solvent: methylene chloride) Fluorescence spectrum: λmax 566 nm (Excitation wavelength: 366 nm Solvent: Methylene chloride) Example 9

[0098]

[Chemical formula 23]

The reaction of the above formula was carried out according to the method of Example 8 except that the formyl body obtained in Reference Example-3 was used. Purification by column chromatography gave 0.563 g of solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 16. m / e: 359 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.21 (t, 6H), 3.42 (q, 4H),
6.61 (d, 1H), 6.71 (d, 2H), 6.80 (s, 1H), 7.20 (d, 1H), 7.40
(t, 1H), 7.49 (d, 1H), 7.62 (d, 2H), 7.68 (t, 1H), 8.22 (d, 1H) Absorption spectrum: λmax 425nm (solvent: methylene chloride) Fluorescence spectrum: λmax 560nm ( Excitation wavelength: 366 nm Solvent: methylene chloride) Example 10

[0100]

[Chemical formula 24]

Using 0.125 g of the compound obtained in Example 9, the reaction of the above formula was carried out according to the method of Example 2 to give 0.115 g.
To give a solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 17. m / e: 407 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.21 (t, 6H), 3.42 (q, 4H),
6.64 (d, 1H), 6.71 (d, 2H), 7.26 (m, 2H), 7.44 (t, 1H), 7.50
(d, 1H), 7.64 (d, 2H), 7.70 (t, 1H), 8.94 (d, 1H) Absorption spectrum: λmax 425nm (solvent: methylene chloride) Fluorescence spectrum: λmax 560nm (excitation wavelength: 366nm solvent: methylene chloride) ) Example 11

[0102]

[Chemical 25]

0.7 g of the compound of Reference Example 3 as a formyl compound
The reaction of the above formula was carried out according to the method of Example 8 except that was used to obtain 0.053 g of a solid. The analysis results of the obtained solid are as follows, and No. It was confirmed that the compound had a structure of 18. m / e: 384 ¹ H-NMR (CDCl ₃ (δ = ppm)): 1.21 (t, 6H), 3.42 (q, 4H),
6.64 (d, 1H), 6.72 (d, 2H), 6.80 (s, 1H), 7.41 (d, 1H), 7.58
(d, 1H), 7.61 (d, 2H), 7.87 (dd, 1H), 8.54 (d, 1H) Absorption spectrum: λmax 447nm (solvent: methylene chloride) Fluorescence spectrum: λmax 585nm (excitation wavelength: 447nm solvent: methylene chloride) ) Example 12

[0104]

[Chemical formula 26]

43 mL of dimethyl sulfoxide and 300 m of toluene
12 g of 60% sodium hydride was added to the solution of L, the temperature was raised from room temperature, and the mixture was stirred at 80 ° C. for 3 hours. This reaction solution is at 35 ℃
After cooling to 18.2 g of methyl 4-methoxysalicylate
Toluene solution (50 mL) was added dropwise. After dropping, the reaction solution
The mixture was stirred at 35 ° C for 3 hours. The reaction solution was poured into 400 g of ice water, the aqueous layer was separated with a separating funnel, and the water tank was neutralized with acetic acid. The resulting white solid was extracted with methylene chloride, the organic layer was washed with saturated saline, and then the solution was concentrated. The obtained solid was suspended and washed with a toluene-hexane mixed system solvent, and the precipitate was collected by filtration to obtain 21 g of a target intermediate as a white solid.

[0106]

[Chemical 27]

Then, 206 mg of 2'-hydroxy-4'-methoxy-2- (methylsulfenyl) acetophenone
Was suspended in 15 mL of toluene, 3 drops of piperidine was added, and the temperature was raised to 50 ° C. A toluene solution (7 mL) of 1.11 mg of the formyl compound obtained by a known method was added to this reaction solution, and the mixture was refluxed for 6 hours. After cooling the reaction solution, hexane 2
0 mL was added and the resulting precipitate was filtered. When the obtained solid is purified by column chromatography, it is the target compound, No. 1 in Table 1. 721 mg of the compound of structure 19 was obtained. m / e: 405 Absorption spectrum: λmax 438 nm (solvent: chloroform) Fluorescence spectrum: λmax 546 nm (excitation wavelength 438 nm, solvent: chloroform) Example 13

[0108]

[Chemical 28]

The reaction of the above formula was carried out according to the method of Example 12 using 468 mg of the formyl compound obtained by a known method. It was purified by column chromatography and is the target compound, No. 1 in Table 1. 312 mg of the compound of the structure 23 were obtained. m / e: 386 Absorption spectrum: λmax 415 nm (solvent: chloroform) Fluorescence spectrum: λmax 515 nm (excitation wavelength 415 nm solvent: chloroform) Example 14

[0110]

[Chemical 29]

According to the method of Example 12, the reaction of the above formula was carried out using 1.13 g of the formyl compound obtained by a known method. It was purified by column chromatography and is the target compound, No. 1 in Table 1. 953 mg of the compound of structure 30 are obtained. m / e: 419 Absorption spectrum: λmax 398 nm (solvent: chloroform) Fluorescence spectrum: λmax 534 nm (excitation wavelength: 398 nm solvent: chloroform) Example 15 An organic electroluminescent device having the structure shown in FIG. 3 was produced by the following method.

A glass substrate 1 on which a transparent conductive film of indium tin oxide (ITO) was deposited to a thickness of 150 nm (manufactured by Geomatec; electron beam film-formed product; sheet resistance 15 Ω) was subjected to ordinary photolithography and hydrochloric acid etching. 2 mm
The anode 2 was formed by patterning a width stripe.
The patterned ITO substrate is washed with ultrapure water, ultrasonic cleaning with a surfactant, ultrasonic cleaning with ultrapure water,
After washing in the order of washing with ultrapure water, it was dried by nitrogen blow, and finally, ultraviolet ozone washing was carried out and it was installed in a vacuum vapor deposition apparatus. After rough evacuation of the above equipment by an oil rotary pump, oil equipped with a liquid nitrogen trap until the degree of vacuum inside the equipment becomes 2.0 × 10 ⁻⁶ Torr (about 2.7 × 10 ⁻⁴ Pa) or less. It was evacuated using a diffusion pump. As a material for the anode buffer layer 3, copper phthalocyanine having the structural formula shown below is used.

[0113]

[Chemical 30]

Using a molybdenum boat, a vapor deposition rate of 0.
16nm / sec, vacuum degree 1.3 × 10 ^-6 Torr (about 1.7 × 10 ^-4 Pa),
A film having a thickness of 10 nm was formed on the anode 2. Next, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl having the structural formula shown below was used as a material for the hole transport layer 4 on the anode buffer layer.

[0115]

[Chemical 31]

[0116] was placed in a ceramic crucible and heated by a tantalum wire heater around the crucible to perform vapor deposition. The temperature of the crucible at this time was controlled in the range of 260 to 280 ° C. The degree of vacuum during vapor deposition was 1.2 × 10 ⁻⁶ Torr (about 1.6 × 10 ⁻⁴ Pa), and the hole transport layer 4 having a film thickness of 60 nm was obtained at a vapor deposition rate of 0.26 nm / sec. Next, as a material of the electron transport layer 5 (light emitting layer), an aluminum 8-hydroxyquinoline complex (E
M-1)

[0117]

[Chemical 32]

On top of the hole transport layer 4, the chromone compound (No. 14) having the structure obtained in Example 8 was placed.
Co-evaporation was performed at a ratio of 100: 1. The temperature of the crucible at this time was controlled in the range of 300 to 315 ℃ and 163 to 164 ℃, respectively. The degree of vacuum during vapor deposition is 0.9 × 10 ^-6 Torr (about 1.2 × 10 ^-4 P
a), EM-1 deposition rate is 0.23nm / sec, total film thickness is 30n
It was m.

Subsequently, the aforementioned 8-hydroxyquinoline complex of aluminum was vapor-deposited on the electron transport layer 5 as a material for the electron injection layer 6. The temperature of the crucible at this time is 296-3
Control was performed in the range of 16 ° C. The degree of vacuum during vapor deposition is 0.8 × 10 ^-6 Tor
r (about 1.1 × 10 ^-4 Pa), deposition rate is 0.23 nm / sec, and film thickness is
It was 45 nm. The substrate temperature during vacuum deposition of the electron injection layer 6 from the hole transport layer 3 was kept at room temperature.

Here, the element on which the electron injection layer 6 has been vapor-deposited is once taken out from the vacuum vapor deposition apparatus into the atmosphere, and a 2 mm wide striped shadow mask is used as a mask for cathode vapor deposition on the ITO of the anode 2. The device is attached to the device so that it is orthogonal to the stripe and placed in another vacuum deposition device, and the vacuum degree in the device is 3.0 × 10 ^-6 Torr in the same manner as the organic layer.
It was exhausted until it became less than (about 4.0 × 10 ^-4 Pa). As the cathode 7, first, magnesium fluoride (MgF ₂ ) was used in a molybdenum boat, the deposition rate was 0.05 nm / sec, and the degree of vacuum was 6.0 × 10 6.
The film was formed on the electron transport layer 7 at ⁻⁶ Torr (about 8.0 × 10 ⁻⁴ Pa) to a thickness of 1.5 nm. Next, aluminum was similarly heated with a molybdenum boat to form an aluminum layer having a film thickness of 40 nm at a vapor deposition rate of 0.44 nm / sec and a vacuum degree of 1.0 × 10 ⁻⁵ Torr (about 1.3 × 10 ⁻³ Pa). Further, copper is also heated on the molybdenum boat to increase the conductivity of the cathode, and the vapor deposition rate is 0.43 nm / sec. And the vacuum degree is 8.0 × 10 ⁻⁶ To.
The cathode 7 was completed by forming a copper layer having a thickness of 40 nm with rr (about 1.1 × 10 ⁻³ Pa). The substrate temperature at the time of vapor deposition of the above three-layer cathode 7 was kept at room temperature.

As described above, the light emission of the size of 2 mm × 2 mm
An organic electroluminescent device having an area portion was obtained. This element
The emission characteristics of the child are shown in Table-2. In Table-2, luminous effect
Rate is 100 cd / m²The value and brightness / current are the brightness-current density characteristics.
The slope of the sex, the voltage is 100 cd / m ²The values in are shown. Stable
The current density is 0.25A / cm²When driven by DC at
It was evaluated from the ratio of luminance after 0 seconds. Luminance ratio (brightness after 60 seconds
Degree / initial brightness) is "excellent" when 0.97 or higher, 0.90 or higher 0.97
Less than "good", less than 0.90 "poor". This element
Shows a bright yellow-green uniform light emission and has excellent stability.
I was there. The wavelength of the emission peak is 547 nm, and the CIE chromaticity coordinate value is x = 0.
39, y = 0.57, the chromone compound (No. 14)
Emission can be efficiently obtained by doping
It was

Comparative Example 1 An organic electroluminescence device was produced in the same manner as in Example 15 except that the chromone compound (No. 14) was not doped in the light emitting layer. The light emission characteristics of this device are shown in Table 2. This device had an emission peak at 537 nm and emitted yellowish green light and had good stability, but the driving voltage was high and the emission efficiency was low. Comparative Example 2 Instead of the chromone compound (No. 14) in the light emitting layer, dimethylquinacridone represented by the following structural formula

[0123]

[Chemical 33]

An organic electroluminescent element was produced in the same manner as in Example 15 except that the above was used. The emission characteristics of this device are shown in the table −
2 shows. This device had an emission peak at 544 nm and exhibited yellow-green emission, and was excellent in stability, but the emission start voltage and drive voltage were high, and the emission efficiency was low.

Example 16 Instead of the chromone compound (No. 14) in the light emitting layer, the chromone compound (N having the structure obtained in Example 9)
o. An organic electroluminescence device was produced in the same manner as in Example 15 except that 16) was used. Table 2 shows the emission characteristics of this device.
Shown in. This device showed bright green uniform light emission and was excellent in stability. The wavelength of the emission peak was 535 nm, and the CIE chromaticity coordinate values were x = 0.33 and y = 0.60. Therefore, luminescence could be efficiently obtained by doping the chromone-based compound (No. 16).

Comparative Example 3 Rubrene represented by the following structural formula was used in the light emitting layer instead of the chromone compound (No. 14).

[0127]

[Chemical 34]

An organic electroluminescence device was produced in the same manner as in Example 15 except that the above was used. The emission characteristics of this device are shown in the table −
2 shows. This device had an emission peak at 563 nm and emitted yellow light and had good stability, but the driving voltage was high and the emission efficiency was low. Example 17 A silanol aluminum compound represented by the following structural formula was used as a hole blocking layer between the electron transport layer 5 (light emitting layer) and the electron injection layer 6.
8-hydroxyquinoline complex

[0129]

[Chemical 35]

10 nm is vapor-deposited on the electron-injecting layer 6 to form a film of aluminum 8-hydroxyquinoline complex (EM-1) having a thickness of 35.
An organic electroluminescence device was produced in the same manner as in Example 15 except that the thickness was changed to nm. The light emission characteristics of this device are shown in Table 2. The device showed a bright yellow-green uniform emission. The wavelength of the emission peak was 550 nm, and the CIE chromaticity coordinate values were x = 0.40 and y = 0.57. Example 18 4,4′-N, N′-dicarbazolylbiphenyl represented by the following structural formula instead of aluminum 8-hydroxyquinoline complex (EM-1) as a host material for a light emitting layer

[0131]

[Chemical 36]

An organic electroluminescence device was produced in the same manner as in Example 17 except that the above was used. The emission characteristics of this device are shown in the table −
2 shows. The device showed a bright green uniform emission. The wavelength of the emission peak is 519 nm, and the CIE chromaticity coordinate value is x = 0.3.
1, y = 0.53. Therefore, the emission wavelength could be changed by changing the host material.

Example 19 Using the ITO volume glass substrate (opening insulating film ITO substrate) having the structure shown in FIG. 4, an organic electroluminescent device having the structure shown in FIG. 5 was prepared by the following method. First, in FIG. 4, indium tin oxide (I
A TO) transparent conductive film having a thickness of 160 nm deposited by a sputtering method was patterned using a normal photolithography technique and hydrochloric acid etching to form an anode ITO2 and a cathode extraction portion ITO8 at a position not in contact with the anode. On the ITO patterned substrate, an opening insulating film 10 having an insulating film opening 9 of 2 mm × 2 mm is provided on the anode ITO2 by using a normal photoresist, and the opening insulating film ITO having the structure shown in FIG. The substrate 11 was created. Next, the opening insulating film ITO substrate 11 is washed with ultrapure water, ultrasonic cleaning with a surfactant, ultrasonic cleaning with ultrapure water,
After washing with water in the order of ultrapure water, it was dried with nitrogen blow. Finally, ultraviolet ozone cleaning was performed. Next, a solution having the following composition is prepared, and the washed opening insulating film ITO substrate 11 is spin-coated under the following conditions and dried to have a thickness of 20 nm.
The anode buffer layer solution coating film was formed. (Anode buffer layer solution composition) Cyclohexanone 10 ml Polymer compound 1 130 mg Electron-accepting compound 1 13 mg Spinner rotation speed 1500 rpm Spinner rotation time 30 seconds (polymer compound 1) A homopolymer consisting only of the following repeating units, weight average Molecular weight (required) is 46,700
Is.

[0134]

[Chemical 37]

(Electron Accepting Compound 1) A compound represented by the following structural formula.

[0136]

[Chemical 38]

Since the anode buffer layer solution coating film is formed on almost the entire surface of the opening insulating film ITO substrate 11, the anode buffer layer solution coating film formed around the opening insulating film 10 was wiped off with chloroform. . Then 10
It was dried at 0 ° C. for 1 hour to form an anode buffer layer 3 having a thickness of 45 nm. Next, with respect to the opening insulating film ITO substrate 11 on which the anode buffer layer 3 is formed, a mask is provided so that an organic layer is not deposited on the anode ITO 2 other than the insulating opening 9 and the cathode extraction portion ITO 8, and vacuum deposition is performed. Installed in the device. After rough evacuation of the above equipment with an oil rotary pump, the degree of vacuum in the equipment was 2.0 × 10 ^-6 Torr (about 2.7 × 10 ^-4
Pa) was evacuated using an oil diffusion pump equipped with a liquid nitrogen trap until below. Next, as a material of the hole transport layer 4 on the anode buffer layer 3, the following structural formula is used.
4,4'-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl

[0138]

[Chemical Formula 39]

[0139] was placed in a ceramic crucible and heated by a tantalum wire heater around the crucible to perform vapor deposition. The temperature of the crucible at this time was controlled in the range of 270 to 280 ° C. The degree of vacuum during vapor deposition was 1.2 × 10 ⁻⁶ Torr (about 1.6 × 10 ⁻⁴ Pa), and the hole transport layer 4 having a film thickness of 40 nm was obtained at a vapor deposition rate of 0.16 nm / sec. Next, as a material for the electron transport layer 5 (light emitting layer), EM-1 and the chromone-based compound (No. 19) having the structure obtained in Example 12 were deposited on the hole transport layer 4 by 100 Co-deposition was performed at a ratio of 1: 1. The temperature of the crucible at this time was controlled within the ranges of 265-270 ° C and 160-162 ° C, respectively. The degree of vacuum during vapor deposition is 0.9 × 10 ^-6 Torr (about 1.2 × 10 ^-4 Pa), EM-1
Had a vapor deposition rate of 0.12 nm / sec and a total film thickness of 30 nm. Subsequently, the above-mentioned EM-1 was deposited on the electron transport layer 5 as a material of the electron injection layer 6. The temperature of the crucible at this time is
The temperature was controlled in the range of 270 to 290 ° C. The degree of vacuum during vapor deposition is 0.8 x 1
0 ^-6 Torr (about 1.1 × 10 ^-4 Pa), vapor deposition rate is 0.17 nm / sec,
The film thickness was 30 nm. Next, the element on which the electron injection layer 6 has been vapor-deposited is once taken out of the vacuum vapor deposition apparatus into the atmosphere, and at least the anode IT outside the opening insulating film 10 is exposed.
The cathode is masked against O2 so that it is not vapor-deposited, and it is installed in another vacuum vapor deposition device, and the vacuum degree in the device is 3.0 × 10 ^-6 Torr (about 4.0 × 10 ^-4 Pa) or less like the organic layer. I evacuated until. First, as a cathode 7, lithium fluoride (LiF) was used in a molybdenum boat, a vapor deposition rate of 0.07 nm / sec, a vacuum degree of 3.0 × 10 ⁻⁶ Torr (about 4.0 × 10 ⁻⁴ Pa), and a film thickness of 0.5 nm. Then, a film was formed on the electron injection layer 6. Next, aluminum is similarly heated with a molybdenum boat to obtain a vapor deposition rate of 0.45n.
m / sec, vacuum degree 6.0 × 10 ^-6 Torr (approximately 8 × 10 ^-4 Pa) and film thickness 80n
An aluminum layer of m was formed and the cathode 7 was completed. As described above, an organic electroluminescent device having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The light emission characteristics of this device are shown in Table 2. This device showed a bright yellow-green uniform light emission and was excellent in stability. The emission peak wavelength is 53
9 nm, CIE chromaticity coordinate value is x = 0.37, y = 0.5
It was 8.

Example 20 An organic electroluminescent device was prepared in the same manner as in Example 19 except that EM-1 and the chromone compound (No. 19) were co-deposited on the light emitting layer 5 at a ratio of 100: 2.3. It was made. The chromone-based compound (No.
The temperature of the crucible of 19) was controlled in the range of 173-175 ° C.
The light emission characteristics of this device are shown in Table 2. This device showed a bright yellow-green uniform light emission and was excellent in stability. The wavelength of the emission peak is 545 nm, and the CIE chromaticity coordinate value is x =
It was 0.40 and y = 0.57.

Example 21 Example 19 was repeated except that the chromone compound (No. 30) having the structure obtained in Example 14 was used in the light emitting layer 5 instead of the chromone compound (No. 19). An organic electroluminescence device was produced in the same manner as in. At this time, the temperature of the crucible of the chromone compound (No. 30) was controlled at 238 ° C. The light emission characteristics of this device are shown in Table 2. This device showed bright green uniform light emission and was excellent in stability. The emission peak wavelength is 528
nm, CIE chromaticity coordinate value is x = 0.34, y = 0.58
Met. Example 22 The following structural formula was used in place of EM-1 in the light emitting layer 5.

[0142]

[Chemical 40]

A point using the compound shown in FIG.
A silanolaluminum 8-hydroxyquinoline complex (Chemical Formula 3) is used as a hole blocking layer between the (light emitting layer) and the electron injection layer 6.
Example 5 except that the electron-injecting layer 6 has a thickness of 20 nm and the thickness of the aluminum 8-hydroxyquinoline complex (EM-1) of the electron injection layer 6 is 20 nm.
An organic electroluminescence device was produced in the same manner as in 9. The light emission characteristics of this device are shown in Table 2. The device showed a bright blue-green uniform emission. The wavelength of the emission peak is 499 nm,
The CIE chromaticity coordinate values were x = 0.27 and y = 0.47. Therefore, by changing the host material, it was possible to obtain an element in which the emission wavelength was changed.

[0144]

[Table 4]

[0145]

INDUSTRIAL APPLICABILITY The present invention provides an organic electroluminescent device having excellent stability and capable of efficiently obtaining high-luminance light emission, and by changing the host material of the light emitting layer, the emission wavelength in a wide wavelength range. Can be changed,
A light emitting material for an organic electroluminescent device is provided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an organic electroluminescence device.

FIG. 2 is a schematic cross-sectional view showing another example of the organic electroluminescence device.

FIG. 3 is a schematic cross-sectional view showing another example of the organic electroluminescent element.

FIG. 4 is a schematic cross-sectional view of an ITO glass substrate used for an organic electroluminescence device.

FIG. 5 is a schematic cross-sectional view showing the layer structure of the organic electroluminescent element created in Example 19.

[Explanation of symbols]

1 substrate 2 Anode ITO 3 Anode buffer layer 4 Hole transport layer 5 Electron transport layer 6 Electron injection layer 7 cathode 8 Cathode extraction part ITO 9 Insulating film opening 10 Opening insulating film 11 Opening insulating film ITO substrate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07D 455/04 C07D 455/04 C09K 11/06 635 C09K 11/06 635 // C09B 57/00 C09B 57 / 00 N PZ (72) Inventor Kyoko Endo 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Prefecture, Mitsubishi Chemical Co., Ltd. (Reference) 3K007 AB02 AB03 AB06 AB11 DB03 4C062 EE59 FF65 4C063 AA01 CC75 CC92 DD79 EE10 4C064 AA12 CC01 DD04 FF01 GG07 HH04 4H056 DD04 DD12 DD15 DD16 DD29 EA13 EA16 FA05

Claims (4)

[Claims] 1. An anode, an organic layer, and a cathode are provided on a substrate.
In an organic electroluminescent device that is sequentially stacked, the organic
The layer contains a compound represented by the following general formula (I)
An organic electroluminescent device characterized by: [Chemical 1] (In the formula, R¹~ R^FourEach independently have a hydrogen atom and a substituent.
Optionally substituted alkyl group and optionally substituted alkyl group
Rucoxy group, halogen atom, cyano group, R ^Five~ R
^TenIs a hydrogen atom or optionally substituted alkyl
Represents a group. Also, R⁸And R⁹Are connected to form a ring
Good and R⁷And R⁸, R⁹And R^TenEach combine to form a ring
It may be formed. Y is an oxygen atom or CR¹¹R¹²
Represents R¹¹And R¹²Are each independently a cyano group or
Is -C (= O) OR¹³(However, R¹³Has a substituent
Represents a good alkyl group. ) Represents. Z is a direct bond or substitution
Thiophene ring which may have a group, which has a substituent
Optionally furan ring, optionally substituted pyrrole
Represents a ring or a benzene ring which may have a substituent.
You n represents 0 or 1. ) 2. R ⁷ and R ⁸ , R ⁸ and R in the general formula (I).
The organic electroluminescent device according to claim 1, wherein when ⁹ or R ⁹ and R ¹⁰ are combined to form a ring, the ring is not an aromatic ring. 3. Z in general formula (I) is a thiophene ring which may have a substituent, a furan ring which may have a substituent, or a pyrrole which may have a substituent. It is a ring, The organic electroluminescent element of Claim 1 or 2 characterized by the above-mentioned. 4. A layer in which an electron transport material and / or a hole transport material is used as a host material as one of the organic layers, and the host compound is doped with a compound represented by the general formula (I). The organic electroluminescent device according to claim 1, which comprises: