JP2000315579A - Organic electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element having excellent light emitting efficiency and emitting light stably for a long time by containing quinacridone compound in a light emitting layer formed between a positive electrode and a negative electrode. SOLUTION: A compound represented by the formula I or II is contained in a light emitting layer. Light emission with high luminance can be accomplished, and especially, an organic electroluminescent element emitting yellow-red light color within a long frequency range can be provided. Even in the continuous drive or pulse, a stable characteristic can be exhibited for a long time. In the formula, one or more pairs of adjacent groups in R1-R8 and R11-R18 are mutually bound so as to form an aliphatic ring or an aromatic ring with carbon atoms in the base skeleton; a hydrogen atom in the ring may be substituted for (A) a halogen atom, an amino group, a nitro group, a cyano group, (B) a C1-18 monovalent hydrocarbon group, (C) -OR21, -COR22, -NHR23, or -NR24R25. Each of R21-R25 represents a C1-18 monovalent hydrocarbon group. A halogen atom may be substituted for a part of hydrogen atoms in the hydrocarbon group of the constituents (B), (C). For example, a compound shown by the formula III or the like is available.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence (EL) device used for a flat display, a flat light source, and the like, and more particularly, to an organic EL device having improved light emission characteristics and excellent life characteristics.

[0002]

2. Description of the Related Art With the rapid progress of technological development in the field of information communication in recent years, great expectations have been placed on flat displays instead of CRTs. Among them, EL elements have been actively studied since they are excellent in high-speed response, visibility, luminance, and the like.

At present, a practically used ZnS / Mn-based inorganic EL device has a problem that the driving voltage is as high as about 100 V and sufficient luminance cannot be obtained. On the other hand, electroluminescence using an organic fluorescent substance has been known for a long time, and much research has been conducted using an anthracene single crystal and the like.
Since the driving voltage was high and the emission luminance was low, it was not possible to develop a practical device.

[0004] However, in 1987, Kodak T
The organic EL device disclosed by Ang et al. has a two-layer laminated structure of organic thin films, can be driven at a low DC voltage of 10 V or less, has a high luminance of 1000 cd / m ^2, and has a luminous efficiency of 1.5 lm / m. W and excellent (Appl.
s. Lett. , 51, 913 (1987)).

Further, tris (8-quinolinolato) aluminum (hereinafter abbreviated as “Alq”) represented by the formula (3) is used as a host material of a light emitting layer, and a coumarin derivative or dicyanomethylene having a high fluorescence quantum yield is used. An organic EL device doped with a derivative (hereinafter abbreviated as “DCM”) has been reported (J. Appl. Phys., 6).
5, 3610 (1989)).

[0006]

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When DCM is used as a fluorescent dye, red light emission from DCM is obtained. This organic EL device emits light efficiently by doping a fluorescent dye into Alq at a low concentration, and the luminous efficiency is improved 1.5 to 2 times. This presentation demonstrated the advantages of low-voltage driving and multi-coloring by designing organic molecules compared to inorganic EL devices, and the study of many organic EL devices such as new organic materials and new cathode materials. Began to take place.

Conventionally known red light emitting layer materials include the above-mentioned DCM derivative, Neil Red (Science).
e 267, 1332 (1995)), perylene derivatives (Appl. Phys. Lett., 64, 187 (1)
993)), europium complex (Chem. Let
t. , 1267 (1991)), but they are not always satisfactory in terms of luminous efficiency and long-term stability, and development of a red luminescent material having excellent luminous efficiency and long life has been desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic EL device which has excellent luminous efficiency and can emit light stably for a long period of time. Another object of the present invention is to provide an organic EL device which can be applied to a multi-color display or a full-color display, and particularly emits yellow to red light.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the present invention relates to an organic EL device having a light-emitting layer containing an organic light-emitting substance between an anode and a cathode. Provided is an organic EL device, wherein the layer contains a compound represented by the following formula (1) or (2).

[0011]

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The above equation (1) or the above equation (2)
Wherein R ^{1 to} R ²⁰ and m and k have the following meanings. R
¹ to R ⁸ and R ¹¹ to R ¹⁸ 1 or more sets of two adjacent groups, taken together, form an aliphatic ring or an aromatic ring with the carbon atoms of the host lattice. A part or all of the hydrogen atoms of the aliphatic ring or the aromatic ring are represented by the following (A) to
It may be substituted by the atom or group of (C). (A) a halogen atom, an amino group, a nitro group or a cyano group. (B) a monovalent hydrocarbon group having 1 to 18 carbon atoms; (C) —OR ²¹ , —COR ²² , —NHR ²³ or —NR
²⁴ R ²⁵ . Here, R ^{21 to} R ²⁵ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups (B) and (C) may be substituted with a halogen atom,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom. The remaining R ^{1 to} R ⁸ and R ¹¹ to
R ¹⁸ represents the following (D) to (F). (D) a hydrogen atom, a halogen atom, an amino group, a nitro group or a cyano group. (E) a monovalent hydrocarbon group having 1 to 18 carbon atoms. ^{(F) -OR 26, -COR 27} , -NHR 28 or -NR
²⁹ R ³⁰ . However, R ²⁶ to R ³⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. Some of the hydrogen atoms of the hydrocarbon groups of (E) and (F) may be replaced by halogen atoms,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom. R ⁹ and R ¹⁰ represent the following (G) to (H). (G) a monovalent hydrocarbon group having 1 to 18 carbon atoms. (H) —OR ³¹ , —NHR ³² or —NR ³³ R ³⁴ . Here, R ^{31 to} R ³⁴ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (G) and (H) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. R ¹⁹
And R ²⁰ represent the following (I) to (J). (I) a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms. (J) -OR ^35, -NHR ³⁶ or -NR ³⁷ R ^38. However, R ^{35 to} R ³⁸ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (I) and (J) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. m and k represent 0, 1 or 2.

Further, the present invention provides an organic EL device containing 0.01 to 20 mol% of a compound represented by the formula (1) or the formula (2) in the light emitting layer. Further, the organic compound represented by the formula (1) or (2) wherein m and k are 1
An L element is provided.

Further, at least one set of two adjacent groups selected from R ^{1 to} R ⁸ and R ^{11 to} R ^{18 of the} compound represented by the formula (1) or (2) is bonded to each other. And an organic EL device in which the ring formed together with the carbon atom of the parent skeleton has a substituted or unsubstituted benzene ring structure or a substituted or unsubstituted indole ring structure. Further, an organic EL containing an 8-oxyquinoline-based complex in the light emitting layer
An element is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In an organic EL device of the present invention, a light-emitting layer containing an organic light-emitting substance sandwiched between an anode and a cathode contains a compound such as a specific quinacridone compound.
Thereby, the light emission is excellent, and stable light emission can be performed for a long time. Further, thereby, a yellow to red organic EL element applicable to multi-color display and full-color display can be obtained.

FIG. 1 is a side view of a basic example of the organic EL device of the present invention, and FIG. 2 is a side view of an application example of the organic EL device of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode,
Reference numeral 3 denotes a light emitting layer containing an organic light emitting substance, and reference numeral 4 denotes a cathode. FIG. 2 shows that a hole transport layer 5 and an interface layer 6 are provided between the anode 2 and the light emitting layer 3, and an electron transport layer 7 and an interface layer 8 are provided between the cathode 4 and the light emitting layer 3. ing.

The substrate 1 in the present invention is a support for an organic EL device, and a transparent substrate such as glass or plastic is generally used. Examples of the material for plastic include polycarbonate, polymethacrylate, and polysulfone.

On the substrate 1, a transparent electrode as the anode 2 is provided. As the transparent electrode, an indium tin oxide (ITO) thin film or a tin oxide film can be usually used.
Further, it may be made of a metal having a large work function, such as aluminum or gold, an inorganic compound conductive material such as copper iodide, or an organic compound conductive material such as poly (3-methylthiophene), polypyrrole, or polyaniline.

This anode is generally formed by a vacuum deposition method, a sputtering method, or the like. In the case of an organic compound conductive material, a solution with an appropriate binder is applied to the substrate, A thin film can be directly formed on a substrate by electrolytic polymerization. The thickness of the anode depends on the required transparency, but the visible light transmittance is 60% or more, preferably 80% or more. Usually, this film thickness is 5
About 1000 nm, preferably 10 to 500 n
m.

A light emitting layer 3 is provided on the anode 2. As the organic light-emitting substance of the light-emitting layer, a compound having a high fluorescence quantum yield, a high electron injection efficiency from the cathode 4, and a high electron mobility is effective, and a known organic light-emitting substance can be used. In the present invention, an 8-oxyquinoline-based complex,
Particularly, an 8-oxyquinoline complex represented by the formula (4) can be preferably used.

[0021]

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In the formula (4), A ^{1 to} A ⁶ represent the following (K) to (M). (K) a hydrogen atom, a halogen atom, an amino group, a nitro group or a cyano group. (L) a monovalent hydrocarbon group having 1 to 18 carbon atoms; ^{(M) -OA 7, -COA 8} , -NHA 9 or -NA ¹⁰
A ^11. However, A ^{7 to} A ¹¹ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups (L) and (M) may be substituted with a halogen atom. In the case of a cyclic structure, 1 to 3 carbon atoms constituting the ring are an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. Further, one set of two adjacent groups of A ^{1 to} A ⁶ may be bonded to each other to form an aromatic ring together with carbon atoms of the parent skeleton. The M is a metal atom, n represents an integer of 1 to 3, L is -OA ^12, A ¹² is any alkyl or aryl group, p is respectively represent an integer of 0 to 2.

The metal atom M of the 8-oxyquinoline complex includes lithium, silver, beryllium, magnesium, calcium, strontium, zinc, cadmium,
Examples include aluminum, gallium, indium, thallium, yttrium, scandium, lanthanum, lead, zirconium, manganese, and lutetium. Of these,
Beryllium, magnesium with high fluorescence quantum yield,
Complexes having aluminum, zinc or scandium as the central metal can be preferably used. Note that the above 8-
The hydrocarbon groups (L) and (M) of the oxyquinoline-based complex may be a saturated hydrocarbon group or an unsaturated hydrocarbon group.

In addition to the above, examples of the organic light emitting substance of the light emitting layer include tetraphenylbutadiene, styryl dyes,
Oxadiazole dyes and the like can be used. The thickness of such a light emitting layer 3 is usually 10 to 200 nm, preferably 20 to 80 nm.

In the present invention, the light emitting layer contains the compound represented by the formula (1) or (2) represented by the quinacridone compound. In the compound of the formula (1) or the formula (2),
R ^{1 to} R ²⁰ and m and k have the following meanings.

At least one pair of two adjacent groups represented by R ^{1 to} R ⁸ and R ^{11 to} R ¹⁸ is bonded to each other to form an aliphatic ring or an aromatic ring together with the carbon atom of the parent skeleton. Some or all of the hydrogen atoms of the aliphatic ring or aromatic ring may be substituted with the following atoms or groups (A) to (C). (A) a halogen atom, an amino group, a nitro group or a cyano group. (B) a monovalent hydrocarbon group having 1 to 18 carbon atoms; (C) —OR ²¹ , —COR ²² , —NHR ²³ or —NR
²⁴ R ²⁵ . Here, R ^{21 to} R ²⁵ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups (B) and (C) may be substituted with a halogen atom,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom.

The remaining R ^{1 to} R ⁸ and R ^{11 to} R ¹⁸ which do not form a ring represent the following (D) to (F). (D) a hydrogen atom, a halogen atom, an amino group, a nitro group or a cyano group. (E) a monovalent hydrocarbon group having 1 to 18 carbon atoms. ^{(F) -OR 26, -COR 27} , -NHR 28 or -NR
²⁹ R ³⁰ . However, R ²⁶ to R ³⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. Some of the hydrogen atoms of the hydrocarbon groups of (E) and (F) may be replaced by halogen atoms,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom.

R ⁹ and R ¹⁰ are the following (G) to (H)
Represents (G) a monovalent hydrocarbon group having 1 to 18 carbon atoms. (H) —OR ³¹ , —NHR ³² or —NR ³³ R ³⁴ . Here, R ^{31 to} R ³⁴ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (G) and (H) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom.

R ¹⁹ and R ²⁰ are represented by the following (I) to (J)
Represents (I) a hydrogen atom, a monovalent hydrocarbon group having 1 to 18 carbon atoms; (J) -OR ^35, -NHR ³⁶ or -NR ³⁷ R ^38. However, R ^{35 to} R ³⁸ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (I) and (J) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. m and k represent 0, 1 or 2.

The above (B), (C), (E),
The hydrocarbon groups of (F), (G), (H), (I) and (J) may be saturated or unsaturated. Further, an aliphatic ring or an aromatic ring may be formed.

By using these compounds, it is possible to emit light with high luminance, and in particular, it is possible to obtain an organic EL device emitting light of a long wavelength range from yellow to red. In addition, stable characteristics can be obtained over a long period of time even in continuous driving or pulse driving.

This is because the compound used in the organic EL device of the present invention has a structure capable of suppressing hydrogen bonding due to those groups when N—H and CＯO are present between the compound molecules. This is presumed to be due to the fact that the heat resistance is improved by the condensed aliphatic ring and aromatic ring structures. The suppression of intermolecular hydrogen bonding has a great effect of suppressing the decrease in brightness due to the aggregation of compound molecules, and the condensed aliphatic and aromatic ring structures enable long-term stability and long-wavelength light emission. . The use of the compounds of the formulas (1) and (2) has a considerable effect even in a small amount, but the effect is particularly high if the amount is 0.01 to 20 mol% in the light emitting layer.

This amount is particularly preferably 0.1 to 10 mol%. When the content is 0.1 mol% or more, the efficiency of energy transfer from the host material of the light emitting layer can be increased.

In particular, when the compound of the formula (1) of the present invention is used, it is preferred that both R ⁹ and R ¹⁰ are the following groups. (I ′) an alkyl group or an aryl group having 1 to 18 carbon atoms. ^{(J ') - OR 35,} -NHR 36 or -NR ³⁷ R ^38. However, R ^{35 to} R ³⁸ are an alkyl group or an aryl group having 1 to 18 carbon atoms.

By doing so, Japanese Patent Laid-Open No.
Compared to the case where a compound in which R ⁹ and R ¹⁰ are a hydrogen atom like the compound described in No. 70773, a compound having excellent suppression of reduction in luminance and long-term stability can be obtained.

Among the compounds of the formulas (1) and (2), compounds in which the condensed aromatic ring is a substituted or unsubstituted benzene ring or a substituted or unsubstituted indole ring have high fluorescence intensity and high luminous efficiency. It is preferable because an excellent organic EL element can be obtained.

In the present invention, as a method for improving the luminous efficiency of the device and at the same time enabling a full-color display, it is also possible to dope the light emitting layer with another dye material having a high fluorescence quantum yield. As such a doped dye material, a known fluorescent organic material can be used.

For example, laser dyes such as stilbene dyes, oxazole dyes, cyanine dyes, xanthene dyes, oxazine dyes, coumarin dyes, acridine dyes, anthracene derivatives, naphthacene derivatives, pentacene derivatives, pyrene derivatives, It can be widely used such as aromatic hydrocarbon-based substances such as perylene derivatives, DCM derivatives, and europium complexes. When a doped dye material is used, its concentration is preferably 0.01 to 30 mol% in the light emitting layer.

In the present invention, the anode 2 and the organic light emitting layer 3
A hole transport layer 5 can be provided between the layers as needed. As the hole transport material of the hole transport layer 5, a material having a low hole injection barrier from the anode 2 and a high hole mobility can be used.

As such a hole transporting material, a known hole transporting material can be used. For example, N, N'-diphenyl-N, N'-bis (3-
Methylphenyl) -1,1′-biphenyl-4,4′-
Aromatic diamine compounds such as diamine (hereinafter abbreviated as "TPD") and 1,1'-bis (4-di-p-tolylaminophenyl) cyclohexane;
The hydrazone compound described in 1 can be used. In addition, poly-
Polymer materials such as N-vinylcarbazole and polysilane can also be preferably used (Appl. Phys. Let.
t. , 59, 2760 (1991)).

[0041]

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Various methods such as a vacuum evaporation method, a dipping method, a spin coating method, and an LB method can be applied as a method for producing the thin film of the hole transport material. In order to produce a uniform thin film of 1 μm or less without defects such as pinholes,
A vacuum deposition method and a spin coating method are preferred.

In the case of spin coating, a binder resin that does not trap holes can be used by dissolving it in a coating solution. Examples of such a binder resin include polyether sulfone, polycarbonate, and polyester. The content of the binder resin is preferably from 10 to 50% by weight which does not decrease the hole mobility.

The material of the hole transporting layer is not limited to the above-mentioned organic substances, but may be p-type compound semiconductors such as metal chalcogenides, metal halides, metal carbides, nickel oxides, lead oxides, and copper iodides. Type hydrogenated amorphous silicon,
A p-type hydrogenated amorphous silicon carbide or the like can also be used.

The hole transport layer of such an inorganic substance can be formed by a known method such as a vacuum evaporation method, a sputtering method and a CVD method. Regardless of whether an organic substance or an inorganic substance is used, the thickness of the hole transport layer is usually from 10 to 20.
0 nm, preferably 20 to 80 nm.

In the present invention, the anode 2 and the hole transport layer 5
Between them, an interface layer 6 may be provided to prevent a leak current, reduce a hole injection barrier, improve adhesion, and the like. Examples of such an interface layer material include 4,4 ′, a derivative of triphenylamine as described in JP-A-4-308688.
4 "-tris {N- (3-methylphenyl) -N-phenylamino} triphenylamine (hereinafter" MTDAT
A "), 4,4 ', 4" -tris {N, N diphenylamino} triphenylamine (hereinafter "TDAT").
A ") or copper phthalocyanine. The film thickness when providing this interface layer is 5 to 100
nm is preferred.

The cathode 4 is provided on the organic light emitting layer 3. Various cathodes can be used, including known cathodes for organic EL devices. For example, there are a magnesium-aluminum alloy, a magnesium-silver alloy, a magnesium-indium alloy, an aluminum-lithium alloy, and aluminum.

In the present invention, the organic light emitting layer 3 and the cathode 4
An electron transporting layer 7 can be provided between the two as necessary. As the electron transporting substance of the electron transporting layer 7, a substance having a high electron affinity and a high electron mobility is required. Substances satisfying such conditions include a cyclopentadiene derivative (Japanese Patent Application Laid-Open No. 2-289675), an oxadiazole derivative (Japanese Patent Application Laid-Open No. 2-216991), a bisstyrylbenzene derivative (Japanese Patent Application Laid-Open No. 1-245087), and 4,4′-.
Diphenyldiphenyl derivatives (Japanese Unexamined Patent Publication No.
3), phenanthroline derivatives (JP-A-5-33145)
9) and triazole derivatives (JP-A-7-90260).

An interface layer 8 may be provided between the electron transporting layer 7 and the cathode 4 if necessary. By providing this interface layer, it is possible to achieve a reduction in driving voltage, an improvement in luminous efficiency, and a longer life. This interface layer has the effect of facilitating electron injection from the cathode and the effect of increasing the adhesion to the cathode.

Examples of such an interface layer material include lithium fluoride (Appl. Phys. Lett., 70, 15).
2 (1997)), alkali metal fluorides, alkaline earth metal fluorides, magnesium oxide,
There are oxides such as strontium oxide, aluminum oxide, and barium oxide. Since such an interface layer material is itself an insulator, the film thickness used is usually 5 nm or less, and it is considered that electrons can be tunnel-injected from the cathode. Preferably, it is 2 nm or less. As long as these layers function as an organic EL element, the layers themselves may be formed of a plurality of layers, or another layer may be interposed between them.

In the organic EL device of the present invention, in order to secure storage stability and driving stability in the atmosphere, it is possible to protect the device from oxygen and moisture in the atmosphere by coating a polymer film or sealing with glass. Good.

The organic EL device of the present invention is used as a full-surface light emitter, used as a backlight or a wall illumination device of a liquid crystal display device, or formed by patterning pixels.
It can be used as a display.

[0053]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 (Example) ITO was deposited on a glass substrate to a thickness of 200 nm to form an anode 2.
(Sheet resistance 7Ω / □). On this anode 2,
The following TPD (formula (5)) was formed to a film thickness of 60 by a vacuum evaporation method.
The hole transport layer 6 was formed by vapor deposition. Next, Alq (formula (3)), which is an aluminum complex of 8-oxyquinoline, and a quinacridone compound represented by the following formula (6) were co-evaporated with a different boat to a thickness of 60 nm to form a light-emitting layer 3. .

This quinacridone compound (formula (6))
A compound of the above formula (1), wherein R ³ and R ⁴ of the formula (1)
And R ⁷ and R ⁸ are each bonded to form two sets of six-membered aromatic rings, and R ⁹ and R ¹⁰ are methyl groups;
and m is 1. The remaining R ¹ , R ² , R ⁵ and R ⁶ are hydrogen atoms. At this time, the concentration of the quinacridone compound (formula (6)) in the light emitting layer was 1.0 mol%. Finally, Mg and Ag were co-deposited to form a 200-nm-thick MgAg (10: 1) cathode alloy, to fabricate an organic EL device. At this time, the degree of vacuum is 8.0 × 10 ⁻⁶ Torr.
r.

[0056]

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Example 2 (Comparative Example) An organic EL device was prepared in the same manner as in Example 1 except that the quinacridone compound represented by the following formula (7) was used instead of the quinacridone compound (formula (6)) of Example 1. Was prepared. The quinacridone (formula (7)) concentration in the light emitting layer of this device was 1.0 mol%.

[0058]

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Example 3 (Comparative Example) An organic EL was prepared in the same manner as in Example 1 except that the quinacridone compound represented by the following formula (8) was used instead of the quinacridone compound (formula (6)) of Example 1. An element was manufactured. The concentration of the quinacridone compound (formula (8)) in the light emitting layer of this device was 1.0 mol%.

[0060]

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Example 4 (Example) The same as Example 1 except that the compound of the following formula (9), which is the compound of the above formula (2), was used in place of the quinacridone compound of the first formula (formula (6)) Thus, an organic EL device was produced. The compound of the formula (9) is a compound of the above formula (2), wherein R ¹³ and R ¹⁴ and R ¹⁷ and R ^{18 of} the formula (2) are respectively bonded to each other to form two sets of six-membered aromatic rings. And R
¹⁹ and R ²⁰ are compounds wherein m is 1 and m is 1. The remaining R ¹¹ , R ¹² , R ¹⁵ and R ¹⁶ are hydrogen atoms. The concentration of the compound of the formula (9) in the light emitting layer of this device was 1.
It was 1 mol%.

[0062]

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Example 5 (Example) 1 part by weight of polyvinyl carbazole and 1 part by weight of TPD (formula (4)) were placed on the anode 2 used in Example 1 with dichloromethane 16
Using a solution dissolved in 0 parts by weight, the number of rotations was 5000 r.
This substrate was spin-coated at a thickness of 60 nm on the substrate at pm to form a hole transport layer. Next, Alq (formula (3)) and the following formula (1)
The light emitting layer 3 was formed by co-evaporating the quinacridone compound represented by the formula (0) and a boat having a thickness of 60 nm using different boats.

This quinacridone compound (formula (10))
Is a compound of the formula (1) wherein R ¹ and R ² and R ⁵ and R ^{6 in} the formula (1) are respectively bonded to form
It is a compound in which two condensed rings of a six-membered ring and a six-membered ring are formed, R ⁹ and R ¹⁰ are methyl groups, and m is 1.
The remaining R ³ , R ⁴ , R ⁷ and R ⁸ are hydrogen atoms. The concentration of the quinacridone compound (formula (10)) in the light emitting layer of this device was 1.5 mol%. Finally, an AlLi alloy (Li content: 0.07% by weight) was deposited to a thickness of 200 nm to form a cathode, whereby an organic EL device was manufactured.

[0065]

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Example 6 (Comparative Example) In place of the quinacridone compound of Example 5 (formula (10)), 4-dicyanomethylene-2- represented by the following formula (11)
Example 5 was repeated except that methyl-6-p-dimethylaminostyryl-4H-pyran (DCM1) was used.
An organic EL device was manufactured. DCM in the light emitting layer of this device
The concentration of 1 was 1.8 mol%.

[0067]

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Example 7 (Comparative Example) An organic EL device was prepared in the same manner as in Example 5 except that neal red represented by the following formula (12) was used instead of the quinacridone compound (formula (10)) of Example 5. Was prepared. The concentration of Neil Red in the light emitting layer of this device was 1.5 mol%.

[0069]

Embedded image Example 8 (Example) On the anode 2 used in Example 1, copper phthalocyanine was deposited by a vacuum deposition method to a thickness of 15 nm to form an interface layer 6. Subsequently, NPD represented by the following formula (13) was deposited to a thickness of 45 nm to form a hole transport layer 5. Next, Alq (formula (3)) and a quinacridone compound (formula (10)) were co-evaporated with a thickness of 60 nm using different boats to form a light emitting layer 3. The quinacridone compound at this time (formula (10))
Was 1.4 mol%. Next, lithium fluoride was deposited to a thickness of 0.5 nm to form an interface layer 8. Finally, A
1 is deposited to a thickness of 200 nm to form a cathode 5 to form an organic EL.
An element was manufactured.

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The luminescent color, luminous efficiency (lm / W), and driving stability of the organic EL device prepared in each of the above examples (Examples and Comparative Examples) (when driven with a constant current of 5 mA / cm ^{2 in} nitrogen) Table 1 shows the measurement results regarding the time (time) required for the initial luminance to drop to half of the original luminance.

[0071]

[Table 1]

[0072]

As described above, according to the present invention,
By using the light emitting layer containing the compound represented by the formula (1) or the formula (2), an organic EL device having high luminous efficiency and excellent life can be obtained. In particular, by using a compound represented by the formula (1) or the formula (2) as a light-emitting substance, an organic EL device that emits yellow to red light, has high luminous efficiency, and has an excellent lifetime can be obtained. The present invention can be applied to various applications within a range that does not impair the effects of the present invention.

[Brief description of the drawings]

FIG. 1 is a side view of a basic example of an organic EL device of the present invention.

FIG. 2 is a side view of an application example of the organic EL element of the present invention.

[Explanation of symbols]

 1: substrate 2: anode 3: light emitting layer 4: cathode 5: hole transport layer 6: interface layer 7: electron transport layer 8: interface layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Jun Irizawa 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in Asahi Glass Co., Ltd. (reference) 3K007 AB00 AB03 AB04 CA01 CA05 CB01 DA00 DB03 EB00 FA01

Claims (5)

[Claims] 1. An organic electroluminescence device having a light emitting layer containing an organic light emitting substance between an anode and a cathode, wherein the light emitting layer contains a compound represented by the following formula (1) or (2). An organic electroluminescence device characterized by the above-mentioned. Embedded image In addition, in the above formula (1) or the above formula (2), R ^{1 to} R ²⁰
And m and k have the following meanings. R ^{1 to} R ⁸ and R
¹¹ one or more sets of two adjacent groups to R ^18, taken together, form an aliphatic ring or an aromatic ring with the carbon atoms of the host lattice. Some or all of the hydrogen atoms of the aliphatic ring or aromatic ring may be substituted with the following atoms or groups (A) to (C). (A) a halogen atom, an amino group, a nitro group or a cyano group. (B) a monovalent hydrocarbon group having 1 to 18 carbon atoms; (C) —OR ²¹ , —COR ²² , —NHR ²³ or —NR
²⁴ R ²⁵ . Here, R ^{21 to} R ²⁵ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups (B) and (C) may be substituted with a halogen atom,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom. The remaining R ^{1 to} R ⁸ and R ¹¹ to
R ¹⁸ represents the following (D) to (F). (D) a hydrogen atom, a halogen atom, an amino group, a nitro group or a cyano group. (E) a monovalent hydrocarbon group having 1 to 18 carbon atoms. ^{(F) -OR 26, -COR 27} , -NHR 28 or -NR
²⁹ R ³⁰ . However, R ²⁶ to R ³⁰ is a monovalent hydrocarbon group having 1 to 18 carbon atoms. Some of the hydrogen atoms of the hydrocarbon groups of (E) and (F) may be replaced by halogen atoms,
In the case of a ring, 1 to 3 carbon atoms constituting the ring may be substituted with an oxygen atom, a nitrogen atom or a sulfur atom. R ⁹ and R ¹⁰ represent the following (G) to (H). (G) a monovalent hydrocarbon group having 1 to 18 carbon atoms. (H) —OR ³¹ , —NHR ³² or —NR ³³ R ³⁴ . Here, R ^{31 to} R ³⁴ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (G) and (H) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. R ¹⁹
And R ²⁰ represent the following (I) to (J). (I) a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms. (J) -OR ^35, -NHR ³⁶ or -NR ³⁷ R ^38. However, R ^{35 to} R ³⁸ are monovalent hydrocarbon groups having 1 to 18 carbon atoms. A part of the hydrogen atoms of the hydrocarbon groups of (I) and (J) may be substituted with a halogen atom, or in the case of a ring, 1 to 3 carbon atoms constituting the ring may be an oxygen atom, It may be substituted by a nitrogen atom or a sulfur atom. m and k represent 0, 1 or 2. 2. The method according to claim 1, wherein the light-emitting layer has the formula (1) or the formula (2).
The compound represented by formula (1) is contained in an amount of 0.01 to 20 mol%.
The organic electroluminescent device according to the above. 3. The organic electroluminescent device according to claim 1, wherein m and k of the compound represented by the formula (1) or (2) are 1. 4. A compound represented by the formula (1) or the formula (2), wherein at least one pair of two adjacent groups selected from R ^{1 to} R ⁸ and R ^{11 to} R ¹⁸ is bonded to each other; The organic electroluminescent device according to any one of claims 1 to 3, wherein the ring formed together with the carbon atom of the parent skeleton is a substituted or unsubstituted benzene ring structure or a substituted or unsubstituted indole ring structure. 5. The organic electroluminescent device according to claim 1, wherein said light emitting layer contains an 8-oxyquinoline-based complex.