JP3258690B2 - Organic light emitting device - Google Patents

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 has an organic phosphor sandwiched between opposing electrodes. Electrons injected from one electrode and holes injected from the other electrode are regenerated in the light-emitting layer. It emits light when combined. For such devices, the use of a single crystal of an organic phosphor such as anthracene or a thin film formed by a vapor deposition method as an illuminant has been attempted, but the density of holes or electrons as carriers is extremely low. Because of its small size and low probability of excitation of functional molecules due to carrier movement or recombination, efficient light emission cannot be obtained, and it is not satisfactory in terms of power consumption and luminance.

Further, it is disclosed in JP-A-57-51781 and JP-A-59-51781 that high hole emission efficiency can be obtained by providing a hole injection layer between the anode and the light emitting layer to increase the density of holes as carriers. -194393, JP-A-63-
No. 2,956,955. Further, in JP-A-63-264692, a light emitting layer provided between a hole injecting / transporting layer and a cathode is composed of a single organic host material capable of sustaining both hole and electron injection and a small amount of fluorescent material. It has been known that the light emission wavelength can be controlled in a wide range and high light emission efficiency can be obtained.

[0004] However, in these, the durability is poor when continuous light emission is performed, and it is common sense that the film is formed by a vacuum deposition method, and therefore, the productivity is poor. Therefore, the present inventors have proposed a method for obtaining an organic light-emitting element having high luminous efficiency, being inexpensive and easy to manufacture, as disclosed in Japanese Patent Application No. Hei 2-2 / 1990.
No. 75298 and Japanese Patent Application No. 3-51106. In these, devices which are inexpensive and easy to manufacture are obtained, but the durability when continuously emitting light is not always sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly efficient organic electroluminescent device having excellent durability.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to improve the durability of a coating type organic electroluminescent device, and as a result, by including a singlet oxygen quencher in a light emitting layer, The inventors have found that a highly efficient organic light-emitting device having excellent durability can be obtained, and completed the present invention. That is, the present invention has a light emitting layer made of an organic material between a pair of electrodes, and the light emitting layer is made of at least a hole transfer donor, an electron transfer donor, and a fluorescent substance. An organic light-emitting device, wherein at least one of the donor and the fluorescent substance is a singlet oxygen quencher.

Hereinafter, the present invention will be described in detail. The organic light emitting element 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 element. Such a light emitting element usually emits light under a constant current condition. However, the brightness gradually decreases even under a constant current condition. The degree of this decrease is greater as the current is greater. At the same time, a non-light-emitting portion is formed with the passage of time, and the area thereof gradually increases. Accordingly, as the area of the non-light-emitting portion increases, the amount of current injected into the light-emitting portion substantially increases, so that the luminance is reduced, that is, the deterioration is promoted, and finally the light-emitting portion disappears. That is, if a non-light-emitting portion cannot be formed or the speed at which the non-light-emitting portion can be formed is low, the light-emitting life of the element is prolonged. However, it has been completely unpredictable that the use of a singlet oxygen quencher as at least one of the essential components as in the present invention can suppress an increase in the area of the non-light-emitting portion and a decrease in luminance at the same time. .

The organic light-emitting device of the present invention has a light-emitting layer made of an organic substance between an anode and a cathode, and the light-emitting layer is composed of a hole-transporting compound as a hole-transfer donor and an electron as an electron-transfer donor. It comprises a mobile compound and a fluorescent substance as a luminescent agent, and uses a singlet oxygen quencher for any of them. Further, the light-emitting layer may contain a polymer binder for the purpose of imparting a film-forming property, and the polymer binder also functions as a hole-transport compound, an electron-transfer compound or a fluorescent substance. May be.

Further, the organic light emitting device of the present invention may have a hole injection layer between the anode and the light emitting layer, and a hole blocking layer between the cathode and the light emitting layer. In this case, a hole injection layer and a hole blocking layer may be provided simultaneously, or one of them may be provided. The singlet oxygen quencher in the present invention is:
A compound that can deactivate singlet oxygen by transferring energy from singlet oxygen.

Specific examples of such compounds include the following compounds. Carotenes such as β-carotene, isoseaxanthen, lutein, p-438, p-422, C ₃₀ -carotenoids,
Such as carotenoids - C _35. Ethylenic compounds 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)-
Triphenylamine derivatives such as 1,1'-biphenyl-4,4'-diamine; and low molecular weight carbazole derivatives such as N-isopropylcarbazole and N-phenylcarbazole.

Another example is a condensed polycyclic aromatic compound. 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
-Dibenzoanthracene, 1,2: 5,6-dibenzoanthracene, periphenylene, 4,7-diphenyl-
1,10-phenanthroline, fluorancene, 3-methylcholanthrene, triphenylene, benzo [ghi]
Perylene, 4H-cyclopenta [def] phenanthrene, and the like, and C1 to C20 alkyl substituents thereof.
Or 1,3-diphenylisobenzofuran, 1,
Aromatic compounds such as 2,3,4-tetraphenyl-1,3-cyclopentadiene and pentaphenylcyclopentadiene;

In addition to the above compounds, Nichola
sJ. Turro, “Modern Molecular
ar Photochemistry ”Chapter 14, The The
Benjamin / Cummings Publis
ing Co. , Inc. (1978), and Harry
H. Wasserman "Singlet Oxyge
There are also compounds exemplified as singlet oxygen quenchers in Chapter n, Chapter 5, Academic Press (1979).

To give another example, bisdithio-α-
Transition metal chelate compounds such as nickel, cobalt or copper complexes having a ligand of diketone, bisphenyldithiol or salicylaldehyde oxime, such as those shown as a singlet oxygen quencher in Japanese Patent Publication No. 38680/1989. Can do things. Alternatively, phenols can be mentioned as another example. Useful phenols include compounds represented by the following formula 1.

[0014]

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(Wherein R1, R2, R3, R4, and R5 may be the same or different, and include a hydrogen atom, C1 to C1
8 linear or branched alkyl groups and phenyl groups (C
1-C6 linear or branched alkyl substituents may be present),-(C1-C6 alkylene group) -CO
O- (C1-C18 alkyl group) or-(C1-C18
6 alkylene group) -OCO- (C1-C18 alkyl group). R6 is a hydrogen atom, a C1-C6 alkylcarbonyl group, a C1-C6 alkyloxy group, a C1-C6
6 represents an alkenylcarbonyl group or a C1 to C6 alkenyloxy group. R7 represents a C1 to C8 linear or branched alkylene group. X is -CO-Y-CO
And Y represents a phenylene group which may have an alkyl substituent. ) Further, 2,6-di-tert-butylphenol,
2,4,6-treater tert-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, "Antioxidant Handbook" by Saruwatari et al., Taiseisha (1971), p. 12-42,
Phenol derivatives which are shown as ultraviolet absorbers, light stabilizers or antioxidants, and "Deterioration and stabilization of polymer materials", CMC (1990) P.122-287. Phenol derivatives shown as stabilizers in pp. 233-253 can be mentioned.

[0017]

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[0018]

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These singlet oxygen quenchers may be used alone or in combination of two or more. The hole-transporting compound used as a hole-transfer donor has an ionization potential of less 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 Can be mentioned.

Preferably, compounds known to have a hole-transporting ability, such as pyrazoline derivatives, stilbene compounds, oxadiazoles, hydrazone compounds, phthalocyanines, and condensed polycyclic aromatic compounds, are used. Polymers such as poly (N-vinylcarbazole), poly (4-diphenylaminophenylmethyl methacrylate), poly (4-diphenylaminophenyl methacrylate), And polysilylene such as (phenylmethylsilylene).

Among the singlet oxygen quencher, N, N 'is preferably used as a hole transfer donor.
-Diphenyl-N, N'-di (3-methylphenyl)-
Triphenylamines such as 1,1'-biphenyl-4,4'-diamine, N-isopropylcarbazole, N
-Tertiary amines such as phenylcarbazole. These hole-transporting compounds may be used alone,
Two or more thereof may be used in combination, and the hole transfer donor may also serve as a singlet oxygen quencher.

As the electron transfer compound used as the electron transfer donor, a compound having an electron affinity of more than 0.1 eV is preferable.
No. 06, for example. Preferably, oxa such as 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-oxadiazole and 2,5-bis (1-naphthyl) oxadiazole Diazole derivatives, oxazole derivatives such as 2- (1-naphthyl) -5-phenyloxazole, styryl compounds such as 2-styrylnaphtho [1,2-d] oxazole, vinylene compounds, 1,1,
1,3,4-oxadiazole skeletons such as diarylbutadienes such as 4,4-tetraphenylbutadiene, and stilbene compounds such as stilbene, which have both functions of an electron transfer compound and a polymer binder; And a polymer containing in a main chain or a side chain.

Among the singlet oxygen quencher, those which can be preferably used as the electron transfer donor include, 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-dibenzoanthracene, 1,2: 5,6-dibenzoanthracene, periphenylene, 4,7-diphenyl-1,10-phenanthroline, fluorancene, 3-methylcholanthrene, Fused polycyclic aromatic compounds such as triphenylene, benzo [ghi] perylene, 4H-cyclopenta [def] phenanthrene, and C1-C20 alkyl-substituted products thereof, or 1,3-diphenylisobenzofuran;
It is an aromatic compound such as 1,2,3,4-tetraphenyl-1,3-cyclopentadiene and pentaphenylcyclopentadiene.

These electron transfer donors may be used alone or in combination of two or more, and the electron transfer donor may also function as a singlet oxygen quencher. As the fluorescent substance used as the luminescent agent, any of a dye for dye laser, a fluorescent whitening agent, or a compound that emits fluorescence by ultraviolet irradiation can be used. As a specific example, Japanese Patent Application No. 3-51106
And the following fluorescent coumarin dyes. 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] quinolizin-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] quinolidine-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] quinolinidin-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] quinolizin-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] quinolizin-11-one,
7-amino-4-methylcoumarin (coumarin 120),
4,6-dimethyl-7-ethylaminocoumarin (coumarin 2).

Alternatively, a xanthene dye may be used. A preferred 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 perchlorate, rhodamine 1
23, Sulfolodamine B, Sulfolodamine 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 fluorescent materials 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).

Among the singlet oxygen quencher, those which can be preferably used as a fluorescent substance as a luminescent agent include, 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-dibenzoanthracene, 1,2,5,6-dibenzoanthracene, periphenylene, 4,7-diphenyl-1,10
-Condensed polycyclic aromatic compounds such as phenanthroline, fluorancene, 3-methylcholanthrene, triphenylene, benzo [ghi] perylene, 4H-cyclopenta [def] phenanthrene, and C1 to C2 thereof;
0 alkyl-substituted product, or 1,3-diphenylisobenzofuran, 1,2,3,4-tetraphenyl-1,3
-Aromatic compounds such as cyclopentadiene and pentaphenylcyclopentadiene.

These luminescent agents may be used alone or in combination of two or more, and the luminescent agent may also function as a singlet oxygen quencher. As the polymer binder, polyvinyl chloride, polycarbonate
Polystyrene, poly (N-vinyl carbazole),
Polymethyl methacrylate, polybutyl methacrylate,
Solvent-soluble resins such as polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, phenol resin, xylene resin,
Curable resins such as petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin and silicone resin can be used.

In the organic electroluminescence device of the present invention, the holes transferred by the hole transfer donor, the holes transferred and the electrons transferred by the electron transfer donor emit light using the fluorescent substance as a hole-electron recombination center. Is what you do. Therefore, in order to efficiently inject and move holes, the ionization potential of the hole transfer donor is equal to or greater 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. When it is the same or lower, high luminous efficiency is obtained. The ionization potential and electron affinity of each compound can be determined from the oxidation potential and reduction potential in the solution, and the compounds can be appropriately combined using the potential as an index. Therefore,
For example, a fluorescent substance having an electron transfer donating ability can be used as an electron transfer donor depending on a combination with another compound, or can be used as a luminescent agent in another case.

In order to form a light emitting layer using a hole transfer donor, an electron transfer donor, and a fluorescent substance, the fluorescent substance is added in an amount of 0.1 part by weight based on 100 parts by weight of the hole transfer donor and the electron transfer donor. The amount is preferably from 01 to 20 parts by weight, and the weight ratio of the electron transfer donor to the hole transfer donor is preferably from 95: 5 to 5:95. If the fluorescent substance is less than 0.01 parts by weight, high luminous efficiency cannot be obtained because the amount of the fluorescent substance is small,
If the amount is more than 20 parts by weight, high luminous efficiency cannot be obtained due to concentration quenching of the fluorescent substance.

When a polymer binder is used, the total amount of the hole transfer donor, the electron transfer donor, and the fluorescent substance is preferably 1 part by weight or less based on 1 part by weight. If it is used in an amount of 1 part by weight or more, the mobility of holes and electrons decreases, and high luminous efficiency cannot be obtained. In any case, the thickness of the light emitting layer is preferably from 50 ° to 1 μm, and most preferably 5000 μm.
Å The following is preferred.

In the organic electroluminescent device of the present invention, a light-emitting layer may be formed on an anode on a support, and then a cathode may be formed, or vice versa. If necessary, a hole injection layer may be formed on the anode, a light emitting layer may be formed, and then a hole blocking layer may be formed thereon, or vice versa. The hole injection layer is formed of a hole-transporting compound, and is formed using a single hole-transporting compound or, if necessary, a polymer binder.

The hole blocking layer is formed of an electron transfer compound, and is formed using a single electron transfer compound or, if necessary, a polymer binder. As the anode, a transparent or opaque conductive material formed on an insulating support is used. When the cathode is opaque, the anode and its support need to be transparent. Preferred examples include tin oxide, indium oxide, and indium tin oxide (IT
O) and the like; metals such as gold, silver and chromium; inorganic conductive substances such as copper iodide and copper sulfide; and conductive polymers such as polythiophene, polypyrrol and polyaniline. .

Preferred as the cathode are, for example, indium, silver, aluminum, lead, magnesium, lanthanum,
Metals such as europium and ytterbium, rare earth elements alone, and translucent or opaque electrodes formed by combining them are exemplified. 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 hole injection layer, and the hole blocking layer may be formed by a vapor deposition method or the like, or may be formed by applying a binder using a solution as necessary. Coating methods include dip coating, spin coating, spray coating,
The coating can be performed by an ordinary well-known coating method such as a roll coating 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 light source such as a backlight of a liquid crystal display or various display devices such as a flat panel display. it can.

[0036]

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

[0037]

Example 1 ITO glass [manufactured by HOYA CORPORATION] was subjected to ultrasonic cleaning in acetone and air-dried, and then an ultraviolet cleaning apparatus [PL-10-110 manufactured by Sen Engineering Co., Ltd.]
For 5 minutes. On this ITO glass, poly (N-vinylcarbazole) [BASF
Luvican M170] 1 part by weight, 0.12 parts by weight of perylene as a singlet oxygen quencher while being an electron transfer donor, and 3- (2′-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6) as a fluorescent substance ) A light emitting layer was formed to a thickness of 1000 ° by dip coating from a 1,2-dichloroethane solution containing 0.02 parts by weight. Then, as a cathode, magnesium and silver were vapor-deposited on a 0.1 cm ² area through a shadow mask so that the atomic ratio of magnesium and silver was 10: 1 to define the area of the device.

When a DC voltage was applied to the device thus manufactured using ITO glass as an anode, green light was emitted uniformly over the entire surface. This device was subjected to 10 mA / cm
^When light was continuously emitted at a constant current density of ² , the initial luminance was 200 cd / m ² , the emission area after continuous light emission for 100 hours was 0.8, and the luminance at that time was 140 cd / m ² .

[0039]

Comparative Example 1 In Example 1, perylene, which is an electron transfer donor and a singlet oxygen quencher, was replaced with 2,
A device was prepared in the same manner as in Example 1, except that 0.9 parts by weight of 5-bis (1-naphthyl) -1,3,4-oxadiazole was used as an electron transfer donor. The device was continuously illuminated at a constant current density of 10 mA / cm ² under a nitrogen stream, and the initial luminance was 200 cd / m ^2.
The device emitted green light, but the emission area after continuous light emission for 100 hours was 0.3, and the luminance at that time was 20 cd / m ² .

As is apparent from the results, by using the singlet oxygen quencher, a decrease in the light emitting area and a decrease in the luminance can be suppressed.

[0041]

Example 2 1 part by weight of poly (N-vinylcarbazole) as a hole transfer donor and 2,5-
Bis (1-naphthyl) -1,3,4-oxadiazole (0.9 parts by weight) was used in the same manner as in Example 1 using rubrene (0.02 parts by weight) as a singlet oxygen quencher at the same time as a fluorescent substance. An element was manufactured. When evaluated in the same manner as in Example 1, this element was found to have an initial luminance of 300 cd / m ^2.
The light emission area after continuous light emission for 100 hours was 0.85, and the luminance at that time was 150 cd / m ² .

[0042]

Example 3 1 part by weight of poly (N-vinylcarbazole) as a hole transfer donor, 0.12 parts by weight of perylene as a singlet oxygen quencher at the same time as an electron transfer donor, and at the same time as a fluorescent material A device was produced in the same manner as in Example 1, except that 0.02 parts by weight of rubrene was used as the oxygen quencher. When evaluated in the same manner as in Example 1, this device emitted yellow light at an initial luminance of 300 cd / m ² , had a light emitting area of 0.95 after continuous light emission for 100 hours, and had a luminance of 200 cd / m ² at that time. Was.

[0043]

Example 4 N, N'-diphenyl-N, N'-NH-diphenyl-N, N'-
Di (3-methylphenyl) -1,1'-biphenyl-
4,4′-diamine, an oxadiazole derivative of the following formula 4 as an electron transfer donor,

[0044]

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As a fluorescent substance, 2- (p-diethylaminostyryl) naphtho [1,2-d] thiazole was used.
Adjust the temperature of each crucible with a vacuum of ^-6 Torr,
A device was prepared and evaluated in the same manner as in Example 1, after vapor-depositing simultaneously on the ITO glass treated in the same manner as in Example 1 and providing a light emitting layer with a thickness of 1500 mm . This element has the initial brightness
There emitted green light at 120cd / m ^2, 100 hours luminance at the light emitting area thereof at 0.80 after continuous light emission 48 cd /
m ² .

[0046]

The organic light emitting device of the present invention is an organic electroluminescent device having good luminous efficiency, sufficient luminance and excellent durability.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-37886 (JP, A) JP-A-3-105896 (JP, A) JP-A-2-250292 (JP, A) JP-A-2- 291696 (JP, A) JP-A-4-212286 (JP, A) JP-A-61-55185 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 33 / 00-33 / 28

Claims (2)

(57) [Claims] [Claim 1 further comprising a light-emitting layer made of an organic material between a pair of electrodes, the light emitting layer is a mixture of at least a hole mobile donors and electron transfer donors fluorescent substance, the hole moving donors
Is the ionization potential of the fluorescent substance.
An electron transfer donor that is the same as or more noble than a char
Has an electron affinity equal to or less than the electron affinity of the fluorescent substance.
, And the organic light emitting device characterized by the hole moving donors, at least one of the electron transfer donors or fluorescent material is a singlet oxygen quencher. 2. The method according to claim 1, wherein the amount of the electron transfer donor is small.
At least a singlet oxygen quencher
The organic light emitting device according to claim 1.