JP2003123972A - Organic light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic light emitting element having a light output of high luminance and long life with extremely high efficiency. SOLUTION: This organic light emitting element comprising at least a pair of electrodes consisting of the anode and the cathode, and one or more layers containing organic compounds put between the electrodes. At least one of the layers containing the organic compounds contains a compound represented by the following general formula [1]. (wherein X2 -X5 each represent H, a halogen atom, a nitro group, or the like, and X1 represents sulfur atom, a sulfoxide group, a sulfone group, or the like).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device, and more particularly to a device that emits light by applying an electric field to a thin film containing an organic compound.

[0002]

2. Description of the Related Art In an organic light emitting device, a thin film containing a fluorescent organic compound is sandwiched between an anode and a cathode and electrons and holes are injected from each electrode to excite excitons of the fluorescent compound. It is an element that uses the light emitted when the excitons return to the ground state.

1987 Research by Kodak Company (Appl.
Phys. Lett. 51, 913 (1987)), an anode is made of ITO, a cathode is made of a magnesium-silver alloy, an aluminum quinolinol complex is used as an electron transporting material and a light emitting material, and a triphenylamine derivative is used as a hole transporting material. A two-layer device with an applied voltage of about 10 V is 1000 cd / m ²
Some light emission has been reported. Related patents include US Pat. No. 4,539,507 and US Pat. No. 4,720,4.
32, US Pat. No. 4,885,211 and the like.

Further, it is possible to emit light from ultraviolet to infrared by changing the kind of the fluorescent organic compound, and recently, various compounds have been actively researched. For example, US Pat. No. 5,151,629, US Pat.
9,783, US Pat. No. 5,382,477, JP-A-2-247278, JP-A-3-255190, JP-A-5-202356, JP-A-9-202.
No. 878, Japanese Patent Laid-Open No. 9-227576, and the like.

Further, in addition to the organic light emitting device using the low molecular weight material as described above, an organic light emitting device using a conjugated polymer is also available at the group of Cambridge University (Nature,
347, 539 (1990)).
In this report, light emission is confirmed in a single layer by depositing polyphenylene vinylene (PPV) in a coating system.
Related patents for organic light emitting devices using conjugated polymers include US Pat. No. 5,247,190 and US Pat.
4,878, US Pat. No. 5,672,678, JP-A-4-145192, JP-A-5-247460 and the like.

As described above, the recent progress in organic light-emitting devices is remarkable, and the features thereof are that it is possible to realize a light-emitting device with high luminance, diversity of emission wavelength, high-speed response, thinness and light weight at a low applied voltage. It suggests the possibility of a wide range of applications.

However, under the present circumstances, further higher brightness light output or higher conversion efficiency is required. Further, there are still many problems in terms of durability such as deterioration with time due to long-term use and deterioration due to atmospheric gas containing oxygen or moisture. Furthermore, when considering application to full-color displays, etc., it is necessary to emit blue, green, and red light with good color purity, but this problem has not yet been sufficiently solved, especially regarding red organic light emitting devices. Hasn't got enough satisfaction.

A large number of compounds having a heterocycle have been studied as fluorescent organic compounds used in the electron transport layer and the light emitting layer. Examples include pyrrole compounds, thiophene compounds, oxazole compounds, oxadiazole compounds, thiadiazole compounds, and the like. Regarding oxazole compounds, which have relatively many reports among them, for example, JP-A-5-214335 and JP-A-9-34335
Japanese Patent Laid-Open No. 188876, Japanese Patent Application Laid-Open No. 11-345686 and the like are available, but none have been obtained that are sufficiently satisfactory in terms of emission brightness, durability and red emission.

Regarding the thiadiazole compound, for example, JP-A-5-222361 can be mentioned, but a sufficiently satisfactory emission brightness and durability and a red light emitting element have not been obtained.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and provides an organic light emitting device having an extremely high efficiency, high brightness, and long life light output. The purpose is to provide.

It is another object of the present invention to provide an organic light emitting device exhibiting a red light emission hue, which is not sufficiently satisfactory.

Another object of the present invention is to provide an organic light emitting device which is easy to manufacture and can be manufactured at a relatively low cost.

[0013]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a pair of electrodes consisting of an anode and a cathode and one or a plurality of electrodes sandwiched between the pair of electrodes. An organic light emitting device having at least a layer containing an organic compound, wherein at least one layer of the layers containing an organic compound contains a specific compound, thereby producing an organic light emitting device having higher efficiency and higher light output. The inventors have found that it is possible to complete the present invention.

That is, the organic light emitting device of the present invention is an organic light emitting device having at least a pair of electrodes consisting of an anode and a cathode and a layer containing one or a plurality of organic compounds sandwiched between the pair of electrodes. At least one of the layers containing an organic compound contains a compound represented by the following general formula [1].

[0015]

[Chemical 2]

(In the formula [1], X _{2 to} X ₅ are hydrogen atom, halogen atom, nitro group, nitrile group, substituted silyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aralkyl group, substituted Or an unsubstituted alkenyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted azomethine group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted X ₁ is a group selected from the group consisting of a substituted ether group and a substituted or unsubstituted heterocyclic group, and X ₁ is a group selected from the group consisting of sulfur atom, sulfoxide, sulfone, oxygen atom and selenium atom. )

In the organic light emitting device of the present invention, at least one of X _{2 to} X _{5 in} the above formula [1] is R ₁ CH.
An azomethine group represented by ═N— (R ₁ is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted The amino group of
It is preferably a substituted or unsubstituted carbonyl group, a substituted or unsubstituted ether group, or a substituted or unsubstituted heterocyclic group. Further, in the above formula [1], X
It is more preferable that at least one of _{2 to} X ₅ is a substituted or unsubstituted amino group.

X ₁ is a sulfur atom, sulfoxide,
Alternatively, it is preferably sulfone.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

First, the compound represented by the above general formula [1] used in the present invention will be explained.

Substituents X _{2 to} X ₅ , R in the general formula [1]
A specific example of ₁ is shown below.

Examples of the substituted silyl group include dimethylsilyl group, trimethylsilyl group, triethylsilyl group, triphenylsilyl group, ter-butyldimethylsilyl group, t
Examples include er-butyldiphenylsilyl group.

Examples of the substituted or unsubstituted alkyl group and aralkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, ter-butyl group, octyl group, benzyl group and phenethyl group.

Examples of the substituted or unsubstituted alkenyl group include vinyl group, allyl group (2-propenyl group), 1-propenyl group, iso-propenyl group and 2-butenyl group.

Examples of the substituted or unsubstituted alkoxy group include methoxy group, ethoxy group, propoxy group, 2-ethyl-octyloxy group, phenoxy group, 4-butylphenoxy group and benzyloxy group.

Examples of the substituted or unsubstituted aryl group are phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 3-chlorophenyl group, 3,5-dimethylphenyl group, triphenylamino group, biphenyl group and terphenyl group. Examples thereof include a phenyl group, a naphthyl group, an anthranyl group, a phenanthryl group, a pyrenyl group, and a ferrocenyl group.

Examples of the substituted or unsubstituted azomethine group include methylimino group, ethylimino group, phenylimino group, (4-dimethylaminophenyl) imino group and (4-dimethylaminophenyl) imino group.
(Cyanophenyl) imino group, (4-fluorophenyl)
Examples thereof include imino group, 2-pyridylimino group, 9-anthranylimino group and 1-pyrenylimino group.

Examples of the substituted or unsubstituted amino group are methylamino group, ethylamino group, dimethylamino group, diethylamino group, methylethylamino group, benzylamino group, methylbenzylamino group, anilino group, diphenylamino group and phenyl. Examples thereof include a tolylamino group and a ditolylamino group.

Examples of the substituted or unsubstituted carbonyl group include acetyl group, propionyl group, isobutyryl group, methacryloyl group, benzoyl group, naphthoyl group, anthryl group and toluoyl group.

Examples of the substituted or unsubstituted ether group include methoxymethyl group, methoxydimethylmethyl group, methoxyethyl group, ethoxymethyl group and phenoxymethyl group.

As the substituted or unsubstituted heterocyclic group,
Examples thereof include a pyridyl group, a bipyridyl group, a methylpyridyl group, a thienyl group, a terthienyl group, a propylthienyl group, a furyl group, a quinolyl group, a carbazolyl group and an N-ethylcarbazolyl group.

The substituents that X _{2 to} X ₅ and R ₁ may have include halogen atoms, nitro groups, nitrile groups, silyl groups, alkyl groups, aralkyl groups and alkenyl groups as described above. Examples thereof include alkoxy groups, aryl groups, azomethine groups, amino groups, carbonyl groups, ether groups, and heterocyclic groups, but are not limited to these.

Next, typical examples of the compound represented by the general formula [1] will be given. However, it is not limited to these compounds.

Compound No. A to e mean the following. a: X = S b: X = SO c: X = SO ₂ d: X = Se e: X = O

[0035]

[Chemical 3]

[0036]

[Chemical 4]

[0037]

[Chemical 5]

Next, the organic light emitting device of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an example of the organic light emitting device of the present invention. FIG. 1 shows a structure in which an anode 2, a light emitting layer 3 and a cathode 4 are sequentially provided on a substrate 1. The light emitting device used here is useful when it has a single hole transporting ability, an electron transporting ability and a light emitting ability by itself, or when a compound having each characteristic is mixed and used.

FIG. 2 is a sectional view showing another example of the organic light emitting device of the present invention. In FIG. 2, an anode 2, a hole transport layer 5, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. In this case, as the light emitting substance, a material having a hole transporting property, an electron transporting property, or both is used for each layer, and the light emitting substance is used in combination with a simple hole transporting substance or an electron transporting substance having no light emitting property. Useful in cases. In this case, the light emitting layer is composed of either the hole transport layer 5 or the electron transport layer 6.

FIG. 3 is a sectional view showing another example of the organic light emitting device of the present invention. FIG. 3 shows a structure in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. This separates the functions of carrier transport and light emission, and is used in combination with a compound having hole transporting property, electron transporting property, and light emitting property in a timely manner to greatly increase the degree of freedom in material selection and to increase the emission wavelength. Since various compounds having different colors can be used, it is possible to diversify the emission hue. Further, it becomes possible to effectively confine each carrier or exciton in the central light emitting layer 3 to improve the light emitting efficiency.

However, FIGS. 1 to 3 show only a very basic device structure, and the structure of the organic light emitting device using the compound of the present invention is not limited to these. For example, various layer configurations can be adopted such as providing an insulating layer at the interface between the electrode and the organic layer, providing an adhesive layer or an interference layer, and forming the hole transport layer from two layers having different ionization potentials.

The compounds represented by the general formula [1] used in the present invention are all excellent in light emitting property, electron injecting property, and electron transporting property as compared with the conventional compounds. Either form can be used.

In particular, the organic layer using the compound represented by the general formula [1] of the present invention is useful as a light emitting layer and also as an electron transporting layer.

In the organic light emitting device of the present invention, at least one kind of the compound represented by the general formula [1] is formed between the anode 2 and the cathode 4 by the vacuum deposition method or the solution coating method. The thickness of the organic layer is less than 10 μm, preferably 0.5 μm or less, more preferably 0.05 to 0.5 μm.
It is preferable to reduce the thickness to m. Further, it can be used together with the light emitting compound and the light emitting layer matrix compound which have been known so far.

In the present invention, the compound represented by the above general formula [1] is used as a constituent component of the light emitting layer and the electron transporting layer. Compounds, light emitting layer matrix compounds, electron transport compounds, charge transport polymer materials,
Luminescent polymer material (for example, compounds shown below)
Can also be used together if desired. However, of course, it is not limited to these.

[0047]

[Chemical 6]

[0048]

[Chemical 7]

[0049]

[Chemical 8]

[0050]

[Chemical 9]

[0051]

[Chemical 10]

[0052]

[Chemical 11]

In the organic light emitting device of the present invention, the layer containing the compound represented by the general formula [1] and the layer containing other organic compound are generally vacuum vapor deposition method or coating method by dissolving in a suitable solvent. To form a thin film. In particular, when the film is formed by the coating method, the film can be formed by combining with an appropriate binder resin.

The binder resin can be selected from a wide range of binder resins, such as polyvinyl carbazole resin,
Polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, acrylic resin, methacrylic resin, butyral resin, polyvinyl acetal resin,
Examples thereof include diallyl phthalate resin, phenol resin, epoxy resin, silicone resin, polysulfone resin, and urea resin, but are not limited thereto. Further, these may be used alone or as a copolymer polymer, or one or more kinds thereof may be mixed.

As the anode material, one having a work function as large as possible is preferable. For example, simple metals such as gold, platinum, nickel, palladium, cobalt, selenium and vanadium or alloys thereof, tin oxide, zinc oxide, indium tin oxide ( A metal oxide such as ITO) or zinc indium oxide can be used. In addition, conductive polymers such as polyaniline, polypyrrole, polythiophene, and polyphenylene sulfide can also be used. These electrode substances may be used alone or in combination of two or more.

On the other hand, a material having a small work function is preferable as the cathode material, such as lithium, sodium, potassium, calcium, magnesium, aluminum, indium, silver,
It can be used as a simple metal or a plurality of alloys of lead, tin, chromium and the like. It is also possible to use a metal oxide such as indium tin oxide (ITO). The cathode may have a single layer structure or a multilayer structure.

The substrate used in the present invention is not particularly limited, but an opaque substrate such as a metal substrate or a ceramic substrate, or a transparent substrate such as glass, quartz or a plastic sheet is used. Further, it is also possible to control the emitted light by using a color filter film, a fluorescent color conversion filter film, a dielectric reflection film or the like on the substrate.

A protective layer or a sealing layer may be provided on the produced element for the purpose of preventing contact with oxygen, moisture or the like. Examples of the protective layer include an inorganic material film such as a diamond thin film, a metal oxide and a metal nitride, a polymer film such as a fluorine resin, polyparaxylene, polyethylene, a silicone resin and a polystyrene resin, and a photocurable resin. To be It is also possible to cover the glass, gas impermeable film, metal, etc., and package the element itself with a suitable sealing resin.

[0059]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 An element having the structure shown in FIG. 3 was prepared.

On the glass substrate as the substrate 1, indium tin oxide (ITO) as the anode 2 is formed by sputtering 12
The film having a film thickness of 0 nm was used as a transparent conductive support substrate. This was sequentially ultrasonically cleaned with acetone and isopropyl alcohol (IPA), washed with boiling IPA, and dried. Furthermore, what was washed with UV / ozone was used as a transparent conductive support substrate.

As the hole transport material, N, N'-diphenyl-N, N'-m-tolyl-4,4'-diamino-1,
A solution adjusted to have a 1'-biphenyl (TPD) concentration of 0.5 wt% was dropped onto the anode 2, and spin coating was first performed at 500 RPM for 10 seconds and then at 1000 RPM for 1 minute. The film was formed. After this 10
The film was dried in a vacuum oven at 80 ° C. for 1 minute to completely remove the solvent in the thin film. The thickness of the formed TPD film (hole transport layer 5) was 50 nm.

Next, tris (8-quinolinolato) aluminum (Alq3) was used as the host material of the light emitting layer 3 on the hole transport layer 5, and the exemplified compound No. 3 was used as the dopant. 1a was co-evaporated to provide a 20 nm light emitting layer 3.
Co-deposition was performed while adjusting the film forming rate so that the host was 0.3 nm / sec and the dopant was 0.1 nm / sec.

Further, Alq3 was formed as the electron transport layer 6 in a film thickness of 40 nm by the vacuum evaporation method. The degree of vacuum at the time of vapor deposition of these organic layers is 4.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.1.
The condition was 3 nm / sec.

Next, using a vapor deposition material made of an aluminum-lithium alloy (lithium concentration: 1 atom%), a metal layer film having a thickness of 10 nm is formed on the above organic layer by a vacuum vapor deposition method, and further a vacuum is formed. An aluminum film having a thickness of 150 nm was provided by an evaporation method to form an aluminum-lithium alloy film (cathode 4). The degree of vacuum during vapor deposition is 1.0 x 10
^The film was formed under the conditions of ⁻⁴ Pa and a film forming rate of 1.0 to 1.2 nm / sec.

The obtained organic EL device was covered with a protective glass plate in a dry air atmosphere and sealed with an acrylic resin adhesive so that the device would not be deteriorated by adsorption of water.

The emission spectrum of the obtained device was 630 n.
Red with a peak at m
No peak around 530 nm of 3 was observed. Also,
Brightness is 150 cd / m ^{2 at} 9V, 300 cd / m at 12V
It was m ² .

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the luminance was small, from initial luminance of 110 cd / m ² to 95 cd / m ² after 72 hours.

Example 2 As the light emitting layer, the above exemplified compound No. An element was prepared and evaluated in the same manner as in Example 1 except that 1a was formed to a thickness of 20 nm by a vacuum vapor deposition method.

The emission spectrum of the obtained device is 623.
Red with a peak at nm and brightness of 9 cd at 130 cd /
It was 285 cd / m ² at m ² and 12 V.

Further, the current density is set to 250 in a nitrogen atmosphere.
It was applied for 72 hours voltage kept at mA / cm ^2, after the initial luminance 100 cd / m ² 72 hours 85cd / m ² and luminance degradation was small.

Example 3 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 2a instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 630.
It was red with a peak at nm and no peak was observed for the host material. Moreover, the brightness is 170 cd / m ² , 12 at 9V.
It was 350 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 130 cd / m ² and 115 cd / m ² after 72 hours.
And the brightness deterioration was small.

Example 4 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 2b instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 636.
It was red with a peak at nm and no peak was observed for the host material. In addition, the brightness is 180 cd / m ² , 12 at 9V.
The V value was 385 cd / m ² .

Further, the current density is set to 250 in a nitrogen atmosphere.
mA / cm ² to keep was applied for 72 hours voltage, 72 hours after the initial luminance 145cd / m ² 135cd / m ²
And the brightness deterioration was small.

Example 5 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 2c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device was 640.
It was red with a peak at nm and no peak was observed for the host material. The brightness is 195 cd / m ² , 12 at 9V.
It was 400 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 150 cd / m ² and after 72 hours was 140 cd / m ^2.
And the brightness deterioration was small.

Example 6 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 2d instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 633.
It was red with a peak at nm and no peak was observed for the host material. The brightness is 165 cd / m ² , 12 at 9V.
It was 340 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 125 cd / m ² and 105 cd / m ² after 72 hours.
And the brightness deterioration was small.

Example 7 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 2e instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 630
It was red with a peak at nm and no peak was observed for the host material. In addition, the brightness is 155 cd / m ² , 12 at 9V.
It was 330 cd / m ² at V.

Further, the current density was set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the luminance was small, from an initial luminance of 110 cd / m ² to 90 cd / m ² after 72 hours.

Example 8 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 10c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 635.
It was red with a peak at nm and no peak was observed for the host material. In addition, the brightness is 180 cd / m ² , 12 at 9V.
It was 360 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 135 cd / m ² and after 72 hours was 115 cd / m ^2.
And the brightness deterioration was small.

Example 9 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 12c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 635.
It was red with a peak at nm and no peak was observed for the host material. In addition, the brightness is 180 cd / m ² , 12 at 9V.
It was 360 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When the voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 140 cd / m ² and after 72 hours was 120 cd / m ^2.
And the brightness deterioration was small.

Example 10 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 15c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 620
It was red with a peak at nm and no peak was observed for the host material. The brightness is 195 cd / m ² , 12 at 9V.
It was 400 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When the voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was changed from 150 cd / m ² to 130 cd / m ² after 72 hours.
And the brightness deterioration was small.

Example 11 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 17c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 509
The color was orange with a peak at nm, and no peak was observed for the host material. Further, the brightness is 215 cd / m ² , 12 at 9V.
It was 420 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 170 cd / m ² and after 72 hours was 150 cd / m ^2.
And the brightness deterioration was small.

Example 12 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 19c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 600
The color was orange with a peak at nm, and no peak was observed for the host material. Moreover, the brightness is 250 cd / m ² , 12 at 9V.
It was 500 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When the voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 200 cd / m ² and after 72 hours was 185 cd / m ^2.
And the brightness deterioration was small.

Example 13 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 24c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device is 610.
It was red with a peak at nm and no peak was observed for the host material. In addition, the brightness is 9 cd, 150 cd / m ² , 12
It was 320 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the luminance was small, from initial luminance of 110 cd / m ² to 90 cd / m ² after 72 hours.

Example 14 Exemplified Compound No. A device was prepared in the same manner as in Example 1 using the exemplified compound 31c instead of 1a, and the same evaluation was performed.

The emission spectrum of the obtained device was 640.
It was red with a peak at nm and no peak was observed for the host material. Moreover, the brightness is 170 cd / m ² , 12 at 9V.
It was 350 cd / m ² at V.

Further, the current density is set to 250 in a nitrogen atmosphere.
When a voltage was applied for 72 hours while maintaining the current at mA / cm ² , the initial luminance was 135 cd / m ² and after 72 hours was 115 cd / m ^2.
And the brightness deterioration was small.

Comparative Example 1 Exemplified Compound No. A device was prepared in the same manner as in Example 1 by using a compound represented by the following structural formula instead of 1a, and the same evaluation was carried out. As a result, only an emission spectrum derived from the emission of the host material was obtained.

[0109]

[Chemical 12]

[0110]

The organic light-emitting device using the compound represented by the general formula [1] of the present invention, as shown in Examples and Comparative Examples, provides red emission which is not satisfactory so far. It also shows highly efficient energy transfer from the host material. Further, as the red light emission, high brightness light emission can be obtained at a low applied voltage, and the durability is excellent.

In particular, the organic layer using the compound represented by the general formula [1] of the present invention is useful as a light emitting layer and also as an electron transporting layer.

Further, the element can be formed by using the vacuum deposition method or the casting method, and the element having a large area can be easily prepared at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an organic light emitting device according to the present invention.

FIG. 2 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

FIG. 3 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

[Explanation of symbols]

1 substrate 2 anode 3 light emitting layer 4 cathode 5 hole transport layer 6 Electron transport layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07D 293/10 C07D 417/12 417/12 285/14 (72) Inventor Kazunori Ueno 3 Shimomaruko, Ota-ku, Tokyo Chome 30-2 Canon Inc. F-term (reference) 3K007 AB03 AB04 AB11 AB18 CA01 CB01 DA01 DB03 EB00 4C036 AD04 AD12 AD13 AD25 AD27 4C056 AA01 AB02 AC04 AD03 AE03 FA01 FB01 FC01 4C063 AA01 BB09 CC67 DD14 EE10

Claims (6)

[Claims] 1. A pair of electrodes comprising an anode and a cathode,
In an organic light emitting device having at least a layer containing one or more organic compounds sandwiched between the pair of electrodes, at least one of the layers containing the organic compound contains a compound represented by the following general formula [1]. An organic light emitting device characterized by the above. [Chemical 1] (In the formula [1], X _{2 to} X ₅ are hydrogen atom, halogen atom, nitro group, nitrile group, substituted silyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted Alkenyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or unsubstituted azomethine group, substituted or unsubstituted amino group, substituted or unsubstituted carbonyl group, substituted or unsubstituted ether A group selected from the group consisting of groups, substituted or unsubstituted heterocyclic groups, X ₁
Is a group selected from the group consisting of sulfur atom, sulfoxide, sulfone, oxygen atom and selenium atom. ) Wherein in the formula [1], among the X ₂ to X _5, at least one azomethine group (R ₁ represented by R ₁ CH = N-a substituted or unsubstituted alkyl group, a substituted Or an unsubstituted aralkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted ether group, a substituted or unsubstituted It represents a substituted heterocyclic group), The organic light emitting device according to claim 1. 3. The organic light emitting device according to claim 2, wherein in the formula [1], at least one of X _{2 to} X ₅ is a substituted or unsubstituted amino group. 4. The organic light emitting device according to claim ₁ , wherein X ₁ in the formula [1] is a sulfur atom. 5. The organic light emitting device according to claim ₁ , wherein X ₁ in the formula [1] is a sulfoxide. 6. The organic light emitting device according to claim ₁ , wherein X ₁ in the formula [1] is sulfone.