JPH05190282A - Organic light emitting element - Google Patents

Abstract

PURPOSE:To improve light emitting efficiency and durability by containing a positive hole movement giving agent, electron movement giving agent, fluorescent material and singlet oxygen guencher in a light emitting layer consisting of organic material, provided between a pair of electrodes. CONSTITUTION:A light emitting layer consisting of organic material is provided between positive and negative poles. The light emitting layer contains a positive hole movement giving agent, electron movement giving agent, fluorescent material and at least one kind of singlet oxygen quencher. In an organic light emitting element, light is emitted by a positive hole, moved and given by the positive hole movement giving agent, and an electron, moved and given by the electron movement giving agent, with the fluorescent material serving as the positive hole-electron recombination center. By adding the singlet oxygenquencher, increase of an area of a nonradiative part and decrease of brightness can be suppressed. The quencher is a compound for deactivating singlet oxygen from oxygen in a singlet condition by moving energy, and as the compound thus obtained, carotenes, for instance, beta-carotene or the like and ethylene compound, for instance, tetramethyl ethylene or the like and others are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly efficient organic light emitting device having excellent durability.

[0002]

2. Description of the Related Art An organic light-emitting device is composed of an organic phosphor sandwiched between counter electrodes, and electrons injected from one electrode and holes injected from the other electrode are regenerated in a light-emitting layer. It emits light when combined. For such a device, it has been attempted to use a single crystal of an organic phosphor such as anthracene or a thin film formed by a vapor deposition method as a light emitter, but the density of holes or electrons as carriers is very high. Since it is small and the probability of excitation of functional molecules due to carrier migration or recombination is low, efficient light emission cannot be obtained, and power consumption and brightness are not satisfactory.

Further, by providing a hole injecting layer between the anode and the light emitting layer to increase the density of holes as carriers, it is possible to obtain a high luminous efficiency, as disclosed in JP-A-57-51781 and JP-A-59. -194393, JP-A-63-
It is known from 295695. Further, in JP-A-63-264692, a light emitting layer provided between a hole injecting and transporting layer and a cathode is provided with a single organic host material capable of sustaining injection of both holes and electrons and a small amount of fluorescent material. It is known that the above configuration makes it possible to control the emission wavelength in a wide range and obtain high emission efficiency.

However, in these, it is common knowledge that the durability is poor when continuously emitting light, and that the film formation is performed by the vacuum vapor deposition method, and therefore the productivity is poor. Therefore, the inventors of the present invention have disclosed a method for obtaining an organic electroluminescence device which has a high luminous efficiency and is inexpensive and easy to manufacture, in Japanese Patent Application Nos. 2-275298 and 3-511.
Proposed in No. 06. In these, an element which is inexpensive and easy to manufacture can be obtained, but the durability when continuously emitting light is not always sufficient.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a highly efficient organic electroluminescent device having excellent durability.

[0006]

Means for Solving the Problems As a result of intensive studies for improving the durability of a coating type organic electroluminescent device, the present inventors have found that a light emitting layer contains a singlet oxygen quencher. The inventors have found that a highly efficient organic electroluminescent device having excellent durability can be obtained and completed the present invention.

That is, the present invention provides an organic light emitting device having a light emitting layer made of an organic material between a pair of electrodes, wherein the light emitting layer comprises at least a hole transfer donor, an electron transfer donor and a fluorescent substance. The present invention proposes an organic light-emitting device characterized in that the light-emitting layer contains at least one kind of singlet oxygen quencher. Further, in an organic light emitting device having a light emitting layer made of an organic material between a pair of electrodes, the light emitting layer being made of at least a hole transfer donor, an electron transfer donor, and a fluorescent substance, between the anode and the light emitting layer. The present invention proposes an organic light-emitting device characterized by having a layer containing a singlet oxygen quencher on either or both of a light-emitting layer and a cathode.

The present invention will be described in detail below. The organic electroluminescence device emits light when holes injected from the anode and electrons injected from the cathode recombine in the light emitting layer, and is called a current injection type light emitting device. Such a light emitting element normally emits light under a constant current condition. However, the brightness gradually decreases even under a constant current condition. The degree of this decrease is larger as the current is larger. At the same time, a non-light emitting portion is formed with the lapse of time, and the area thereof gradually increases. Therefore, as the area of the non-light emitting portion increases, the amount of current injected into the light emitting portion substantially increases, resulting in a decrease in brightness.
That is, the deterioration is promoted, and finally the light emitting portion is lost. That is, if the non-light emitting portion is not formed or if the formation speed is slow, the light emission life of the element is extended.
However, it is totally expected that the area increase of the non-light emitting portion can be suppressed by simultaneously adding a singlet oxygen quencher or providing a layer containing a singlet oxygen quencher as in the present invention, and at the same time, a decrease in brightness can be suppressed. It was impossible.

In the organic light-emitting device of the present invention, the holes transferred and donated by the hole transfer donor and the electrons transferred and donated by the electron transfer donor emit light using the fluorescent substance as the hole-electron recombination center. It is a thing. Therefore, in order to efficiently inject and move holes, the ionization potential of the hole transfer donor is equal to or higher than the ionization potential of the fluorescent substance, and the electron affinity of the electron transfer donor is the electron affinity of the fluorescent substance. High luminous efficiency is obtained when the same as or less than. The ionization potential and electron affinity of each compound can be determined from the oxidation potential and reduction potential in the solution, and each compound can be properly combined using these as an index.

The singlet oxygen quencher includes a compound having a function as a hole transfer donor, an electron transfer donor or a fluorescent substance, and these compounds are respectively a hole transfer donor and an electron transfer donor. In order to obtain high luminous efficiency and high durability as a fluorescent substance, the combination of each compound is important as described above, and at the same time, high hole transfer ability or electron transfer ability is required. Limited by the possible singlet oxygen quenchers. However, in the method of adding a singlet oxygen quencher to the light emitting layer or providing a layer containing a singlet oxygen quencher of the present invention, there is no limitation on the singlet oxygen quencher that can be used. Therefore, both high luminous efficiency and high durability can be easily satisfied.

The organic light emitting device of the present invention has a light emitting layer made of an organic material between an anode and a cathode, and the light emitting layer comprises a hole transfer donor, an electron transfer donor, a fluorescent substance and a singlet oxygen quencher. Become. Further, a layer containing a singlet oxygen quencher may be provided between the anode and the light emitting layer, between the light emitting layer and the cathode, or both. Further, the light emitting layer may not include a singlet oxygen quencher, and a layer containing a singlet oxygen quencher may be provided between the anode and the light emitting layer, between the light emitting layer and the cathode, or both.

The light-emitting layer of the present invention may contain a polymer binder for the purpose of imparting film-forming properties, and may also contain a hole-transporting compound, an electron-transporting compound, a fluorescent substance or a singlet oxygen quenching compound. The polymer binder may also have the function of char. Further, a hole injection layer may be provided between the anode and the light emitting layer, and a hole blocking layer may be provided between the cathode and the light emitting layer. In this case, the hole injection layer and the hole blocking layer may be provided at the same time, or either one of them may be provided, and the hole injection layer or the hole blocking layer may also serve as a layer containing a singlet oxygen quencher. Good.

The singlet oxygen quencher used in the present invention is a compound capable of deactivating singlet oxygen by energy transfer from oxygen in the singlet state. Specific examples of such compounds include the following compounds. Carotene, for example, β-carotene, isosexanthene, lutein, p-438, p-
422, C ₃₀ -carotenoid, C ₃₅ -carotenoid and the like. An ethylenic compound such as tetramethylethylene,
Cyclopentene, cyclohexene, 2,5-dimethyl-
2,4-hexadiene, 1,3-cyclopentadiene,
1,3-cyclopentadiene, α-terpinene and the like. Amines such as diethylamine, triethylamine,
1,4-diazabicyclooctane (DABCO), N-
Ethylimidazole, N, N'-diphenyl-N, N '
-Di (3-methylphenyl) -1,1'-biphenyl-
Triphenylamine derivatives such as 4,4′-diamine,
Examples thereof include low molecular weight carbazole derivatives such as N-isopropylcarbazole and N-phenylcarbazole. Other examples include fused polycyclic aromatic compounds. For example, naphthalene, dimethylnaphthalene, dimethoxyanthracene, anthracene, diphenylanthracene, phenanthrene, pyrene, chrysene, perylene, coronene, tetracene, pentacene, rubrene, 3,4-
Benzofluoranthrene, 2,3-benzofluorene,
1,12-benzoperylene, 3,4-benzopyrene,
4,5-benzopyrene, 9,10-bis (4-methoxyphenyl) anthracene, 9,10-diphenylanthracene, 1-chloro-9,10-diphenylanthracene, 9-phenylanthracene, 4,5-methylenephenanthrene , Decacyclene, 1,2: 3,4-dibenzanthracene, 1,2: 5,6-dibenzanthracene, perifylene, 4,7-diphenyl-1,10
-Phenanthroline, fluoranthene, 3-methylcholanthrene, triphenylene, benzo [ghi] perylene, 4H-cyclopenta [def] phenanthrene, etc., and C1-C20 alkyl-substituted products thereof. Alternatively 1,3-diphenylisobenzofuran, 1,2,
Examples include aromatic compounds such as 3,4-tetraphenyl-1,3-cyclopentadiene and pentaphenylcyclopentadiene.

In addition to the above compounds, Nichola
sJ. Turro, “Modern Molecule
ar Photochemistry ”Chapter 14, The
Benjamin / Cummings Publics
ing Co. , Inc. (1978), and Harry
H. wasserman "Singlet Oxyg
en ”Chapter 5, Academic Press (1979),
Some compounds are exemplified as singlet oxygen quenchers.

Another example is bisdithio-α-
Examples of transition metal chelate compounds such as nickel, cobalt, or copper complexes having a diketone, bisphenyldithiol, or saltylaldehyde oxime as a ligand, as shown in JP-B-1-38680 as a singlet oxygen quencher. I can do things. Alternatively, phenols can be mentioned as another example. Examples of useful phenols include the compounds represented by the following chemical formula 1.

[0016]

[Chemical 1]

(In the formula, R1, R2, R3, R4 and R5 may be the same or different, and a hydrogen atom, C1 to C1
8 straight-chain or branched alkyl group, phenyl group (C
1 to C6 may have a linear or branched alkyl substituent),-(C1 to C6 alkylene group) -CO
O- (C1-C18 alkyl group), or-(C1-C
6 alkylene group) -OCO- (C1-C18 alkyl group). R6 is a hydrogen atom, C1 to C6 alkylcarbonyl group, C1 to C6 alkyloxy group, C1 to C
6 represents an alkenylcarbonyl group of 6 or a C1-C6 alkenyloxy group. R7 represents a C1-C8 linear or branched alkylene group. X is -CO-Y-CO
Represents-, and Y represents a phenylene group which may have an alkyl substituent. ) Further, 2,6-ditert-butylphenol,
2,4,6-treatary butylphenol,
Specific examples include 2,4,6-trinitrophenol, α-tocopherol (vitamin E), and compounds represented by the following chemical formulas 2 and 3.

In addition to the above, "Handbook of Antioxidants" by Saruwatari et al., Taiseisha (Showa 51), p. 12-42,
122-287, a phenol derivative described as an ultraviolet absorber, a light stabilizer, or an antioxidant, and "Degradation and Stabilization of Polymer Materials" CMC (1990) p. 233-25
Phenol derivatives shown as stabilizers in 3 can be mentioned.

[0019]

[Chemical 2]

[0020]

[Chemical 3]

These singlet oxygen quenchers may be used alone or in combination of two or more. The hole transfer compound used as the hole transfer donor has an ionization potential smaller than 8 eV,
1 × 10 ⁵ V / hole mobility in the electric field strength of cm ² of 1 × 10 ^{over 10} cm ² / V · sec or more compounds are used, is shown in Japanese Patent Application No. 3-51106 Specific examples Such compounds can be mentioned.

Preferably, N, N'-diphenyl-N,
Triphenylamines such as N'-di (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine,
It has hole transfer ability such as tertiary amines such as N-isopropylcarbazole and N-phenylcarbazole, pyrazoline derivatives, stilbene compounds, oxadiazoles, hydrazone compounds, phthalocyanines, condensed polycyclic aromatic compounds. Known compounds are used, and those having a function of a hole-transporting compound and a polymer binder include poly (N-vinylcarbazole), poly (4-diphenylaminophenylmethylmethacrylate), and poly (4- Examples thereof include polymers such as diphenylaminophenylmethacrylate) and polysilylenes such as poly (phenylmethylsilylene).

These hole-transporting compounds may be used alone or in combination of two or more.
The electron transfer compound used as the electron transfer donor is preferably a compound having an electron affinity of more than 0.1 eV, and specific examples thereof include compounds described in Japanese Patent Application No. 3-51106. it can. More preferably, 2- (4'-tert-butylphenyl) -5-
Oxadiazole derivatives such as (4 ″ -biphenyl) -1,3,4-oxadiazole and 2,5-bis (1-naphthyl) oxadiazole, 2- (1-naphthyl)-
An oxazole derivative such as 5-phenyloxazole,
Examples thereof include styryl compounds such as 2-styrylnaphtho [1,2-d] oxazole, vinylene compounds, diarylbutadienes such as 1,1,4,4-tetraphenylbutadiene, stilbene compounds such as stilbenes, and electron transfer compounds. As a polymer having a function as a polymer binder, there may be mentioned a polymer containing a 1,3,4-oxadiazole skeleton in its main chain or side chain.

These electron transfer donors may be used alone or in combination of two or more. The fluorescent substance used as the luminescent agent can be arbitrarily selected from dyes for dye lasers, fluorescent whitening agents, and compounds that exhibit fluorescence upon irradiation with ultraviolet rays. As a specific example, a compound as shown in Japanese Patent Application No. 3-51106 can be mentioned. Preferably phenanthrene, chrysene, coronene, rubrene, perylene,
Fused polycyclic aromatic compounds such as 9,10-diphenylanthracene and derivatives thereof, and further, for example, the following fluorescent coumarin dyes can be mentioned. 7-hydroxy-4-methylcoumarin (coumarin 4),
7-diethylamino-4-methylcoumarin (coumarin 1), 7-dimethylaminocyclopenta [c] -coumarin (coumarin 138), 1,2,4,5,3H, 6H,
10H-tetrahydro-8-methyl [1] benzopyrano [9,9a, 1-gh] quinolidin-10-one (coumarin 102), 7-amino-4-trifluoromethylcoumarin (coumarin 151), 1,2,4 , 5, 3H, 6
H, 10H-tetrahydro-9-cyano [1] benzopyrano [9,9a, 1-gh] quinolizin-10-one (coumarin 337), 1,2,4,5,3H, 6H, 1
0H-tetrahydro-9-carbo-t-butoxy [1]
Benzopyrano [9,9a, 1-gh] quinolizine-10
-One (coumarin 338), 7-ethylamino-6-methyl-4-trifluoromethylcoumarin (coumarin 30
7), 1,2,4,5,3H, 6H, 10H-tetrahydro-9-carbethoxy [1] benzopyrano [9,9
a, 1-gh] quinolidin-10-one, 7-diethylamino-3- (1-methylbenzimidazolyl) coumarin, 7-dimethylamino-4-trifluoromethylcoumarin (coumarin 152), 1,2,4,5 , 3H, 6
H, 10H-tetrahydro-9-carboxy [1] benzopyrano [9,9a, 1-gh] quinolizin-10-one (coumarin 314), 1,2,4,5,3H, 6H,
10H-Tetrahydro-9-acetyl [1] benzopyrano [9,9a, 1-gh] quinolizin-10-one (coumarin 334), 3- (2-benzimidazolyl) -7
-N, N-diethylaminocoumarin (coumarin 7),
1,2,4,5,3H, 6H, 10H-tetrahydro-
8-trifluoromethyl [1] benzopyrano [9,9
a, 1-gh] quinolidin-10-one (coumarin 1
53), 3- (2-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 7-diethylaminocoumarin, 7-diethylamino-4-trifluoromethylcoumarin, 2,3,6,7-tetrahydro-9. -(Trifluoromethyl) -1H, 5H, 11H- [1] benzopyrano [6,7,8-ij] quinolidin-11-one,
7-amino-4-methylcoumarin (coumarin 120),
4,6-dimethyl-7-ethylaminocoumarin (coumarin 2) and the like.

Alternatively, a xanthene dye may be used. A preferable example of the xanthene dye is a rhodamine dye as exemplified below. Rhodamine B, Rhodamine 6
G, Rhodamine 6G perchlorate, Rhodamine 19 perchlorate, Rhodamine 101 internal salt, Rhodamine 1
10, Rhodamine 116 Park Loreto, Rhodamine 1
23, Sulfolodamin B, Sulfolodamin 10
1, and so on.

Another preferred example of a xanthene dye is a fluorescein dye such as fluorescein, 2 ', 7'-dichlorofluorescein. Examples of other preferred phosphors are styryl dyes such as: 2- (p-dimethylaminostyryl) quinoline, 2-
(P-dimethylaminostyryl) benzoxazole,
4- (p-dimethylaminostyryl) quinoline, 2-
(P-Dimethylaminostyryl) -6-ethoxyquinoline, 2- (p-dimethylaminostyryl) benzothiazole, 2- (p-dimethylaminostyryl) naphtho [1,2-d] oxazole, 2- (p-dimethyl Aminostyryl) -3,3'-dimethyl-3H-indole, 2- (p-dimethylaminostyryl) naphtho [1,
2-d] thiazole, 4-dicyanomethylene-6- (p
-Dimethylaminostyryl) -2-methyl-4H-pyran (DCM).

These luminescent agents may be used alone or in combination of two or more. As the polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N-vinylcarbazol), polymethymethacrylate, polybutylmethacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene. , Hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose,
Curing of solvent-soluble resins such as vinyl acetate, ABS resin, polyurethane resin, phenol resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicone resin, etc. Resin can be used.

To use these as a light emitting layer, the fluorescent substance is preferably 0.01 part by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the hole transfer donor and the electron transfer donor together. And the hole transfer donor are 9 by weight.
5: 5 to 5:95 are preferred. When a singlet oxygen quencher is added to the light-emitting layer, it depends on the quenching rate constant of the singlet oxygen quencher used, but the hole transfer donor, the electron transfer donor, and the fluorescent substance are combined in a total amount of 100.
The amount of the singlet oxygen quencher is preferably 0.01 part by weight or more and 20 parts by weight or less with respect to parts by weight. If it is less than 0.01 parts by weight, the effect is small, and if it is 20 parts by weight or more, the luminous efficiency may decrease.

When a polymer binder is used, a hole transfer donor, an electron transfer donor and a fluorescent substance may be used together, or a hole transfer donor, an electron transfer donor, a fluorescent substance and a singlet oxygen quenching agent. The total amount of char is preferably 1 part by weight or less with respect to 1 part by weight. When it is used in an amount of 1 part by weight or more, the hole and electron mobility decreases, and high luminous efficiency cannot be obtained.

The thickness of the light emitting layer is 5 in each case.
It is preferably 0 A or more and 1 μm or less, and most preferably 5000 A or less. When a layer containing a singlet oxygen quencher is provided, the singlet oxygen quencher may be formed alone or, if necessary, a polymer binder may be used to form the layer. At this time, the amount of the singlet oxygen quencher is preferably 1 part by weight or more with respect to 1 part by weight of the polymer binder.

In the organic electroluminescence device of the present invention, the light emitting layer may be formed on the anode on the support and then the cathode, or vice versa. Further, if necessary, a hole injection layer or a layer containing a singlet oxygen quencher is formed on the anode, and then a light emitting layer is formed, and a hole blocking layer or a singlet oxygen quencher is further formed thereon. Layers may be formed, or vice versa.

The hole injecting layer is formed of a hole transporting compound, and is formed by using the hole transporting compound alone or, if necessary, a polymer binder. The hole blocking layer is formed of an electron-transporting compound, and is formed by using the electron-transporting compound alone or, if necessary, a polymer binder.
As the anode, a transparent or opaque conductive material formed on an insulating support is used, but when the cathode is opaque, the anode and its support must be transparent.
Preferred examples include conductive oxides such as tin oxide, indium oxide, and indium tin oxide (ITO), or gold,
Examples thereof include metals such as silver and chromium, inorganic conductive substances such as copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole and polyaniline.

Preferred cathodes are, for example, indium, silver, aluminum, lead, magnesium, lanthanum,
Examples thereof include metals such as europium and ytterbium, rare earth simple substances, and semitransparent or opaque electrodes formed by combining these. The insulating support is not particularly limited, and may be a flexible support such as polyethylene terephthalate, cellulose acetate, polycarbonate, polyvinyl chloride, or glass.

The light emitting layer, the layer containing a singlet oxygen quencher, the hole injecting layer, and the hole blocking layer may be formed by a vapor deposition method or the like. It may be formed by coating. The coating can be carried out by an ordinary well-known coating method such as a dip coating method, a spin coat method, a spray coat method and a roll coat method.

Since the organic electroluminescent device manufactured by the method of the present invention has excellent durability and high luminous efficiency, it can be used as a surface emitting light source such as a backlight of a liquid crystal display or various display devices such as a flat panel display. Can be used.

[0036]

The present invention will be described in more detail with reference to the following examples.

[0037]

Examples 1 to 8 and Comparative Example 1 ITO glass [HOYA
After ultrasonic cleaning in acetone and air-drying, UV cleaning device [P manufactured by Sen Engineering Co., Ltd.
L-10-110] for 5 minutes. On this ITO glass, poly (N-vinylcarbazole) as a hole transfer donor [Luvican M170 manufactured by BASF]
1 part by weight, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole as an electron transfer agent 0.9 part by weight, 3- (2'-benzothiazolyl)-as a fluorescent substance
A light emitting layer was formed to a thickness of 1000 A by dip coating from a 1,2-dichloroethane solution containing 0.02 part by weight of 7-diethylaminocoumarin (hereinafter abbreviated as coumarin 6). Then, as a negative electrode, magnesium and silver were vapor-deposited in an area of 0.1 cm ² through a shadow mask so that the atomic ratio of magnesium and silver was 10: 1 to define the area of the device. This light emitting device was designated as Comparative Example 1.

In addition to the above compounds, 0.02 parts by weight of a singlet oxygen quencher shown in Table 1 was added to the light emitting layer to prepare devices in the same manner as Examples 1 to 8. When a direct current voltage was applied to the device thus manufactured using ITO glass as an anode, green light was uniformly emitted over the entire surface. When each element was made to continuously emit light at a constant current density of 10 mA / cm ² under a nitrogen stream, the light emitting area gradually decreased. Table 1 shows the ratio of the light emitting area after continuous light emission for 100 hours to the first light emitting area and the light emitting luminance. As is clear from this result, by adding the singlet oxygen quencher, it is possible to suppress the reduction of the light emitting area and also the luminance.

[0039]

Example 9 Pentacene was deposited as a singlet oxygen quencher layer on an ITO glass washed in the same manner as in Example 1 at a vacuum degree of 3 × 10 ⁻⁶ Torr to a thickness of 300 A. On top of this, N, N'-diphenyl-N, N'-di (3-methylphenyl) -1, as a hole transfer donor,
1'-biphenyl-4,4'-diamine, an oxadiazole derivative represented by the following formula 4 as an electron transfer donor,

[0040]

[Chemical 4]

2- (p-diethylamino) as a fluorescent substance
Styryl) naphtho [1,2-d] thiazole was used.
3 × 10 so that each weight ratio is 1: 1: 0.01
^-6Adjust the temperature of each crucible with the vacuum degree of Thor,
Simultaneous vapor deposition on ITO glass treated as in Example 1.
Then, after providing the light emitting layer to a thickness of 1500 A,
A device was prepared and evaluated in the same manner. Initial brightness of this device
Is 120 cd / m²And the emission after 100 hours of continuous light emission
The light area is 0.85 and the brightness at that time is 68 cd / m. ²And
It was.

[0042]

Example 10 On an ITO glass washed in the same manner as in Example 1, 1 part by weight of 1,4-diazabicyclo- [2,2,2] octane and a styrenated alkyd resin [Styresol; Dainippon Ink and Chemicals, Inc.] were used. Preparation] A film consisting of 1 part by weight was applied by dip coating from a toluene solution to a thickness of 300 A, and then heated at 100 ° C. for 30 minutes to be cured to form a singlet oxygen quencher layer. On this, a light emitting layer and a negative electrode were formed in the same manner as in Comparative Example 1. The initial brightness of this device is 150
a cd / m ^2, the light emitting area after 100-hour continuous light emission luminance at that time 0.90 was 72cd / m ^2.

[0043]

[Embodiment 11] Copper phthalocyanine [manufactured by Toyo Ink Co., Ltd.] as a hole injection layer is vapor-deposited on an ITO glass washed in the same manner as in Embodiment 1 at a vacuum degree of 3 × 10 ⁻⁶ Torr to a thickness of 300 A. did. On this, 1 part by weight of poly (N-vinylcarbazole) as a hole transfer donor and 2- (4'-tert-butylphenyl) -5- as an electron transfer donor.
Example 4 using (4 ″ -biphenyl) -1,3,4-oxadiazole, coumarin 6 as the fluorescent substance and 0.02 part by weight of β-carotene as the singlet oxygen quencher. An element was manufactured in the same manner, the initial luminance of this element was 90 cd / m ² , the light emitting area after continuous light emission for 100 hours was 0.80, and the luminance at that time was 75 cd / m ^2.
It was m ² .

[0044]

[Table 1]

[0045]

Industrial Applicability The organic light emitting device of the present invention is an organic electroluminescence device having good luminous efficiency, sufficient brightness, and excellent durability.

Claims (2)

[Claims] 1. A light emitting layer made of an organic material is provided between a pair of electrodes, and the light emitting layer comprises at least a hole transfer donor, an electron transfer donor and a fluorescent substance, and the light emitting layer has at least one single layer. An organic light-emitting device comprising an oxygen quencher. 2. A light emitting layer made of an organic material is provided between a pair of electrodes, and the light emitting layer comprises at least a hole transfer donor, an electron transfer donor and a fluorescent substance, and moreover, light is emitted between the anode and the light emitting layer. An organic light-emitting device having a layer containing a singlet oxygen quencher on either or both of the layer and the cathode.