JP2003282270A - Organic electroluminescent device and display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device attaining the improvement of luminance and durability at the same time, and to provide a display using the same and having high luminance and a long life. <P>SOLUTION: This organic electroluminescent device is characterized in including, at least, one type of compounds expressed by a general formula (1). (In the formula, Z expresses n valence bond group or a simple bond, Ar expresses bivalent arylene group, R<SB>1</SB>-R<SB>8</SB>express hydrogen atom or substituted group respectively. The n expresses integer not less than 2 and not more than 6. Among R<SB>1</SB>-R<SB>8</SB>, adjoining substituted groups may be mutually condensed and formed into a ring. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence (hereinafter abbreviated as organic EL) element and a display device using the same. More specifically, the present invention relates to an organic electroluminescence element excellent in emission luminance and the organic electroluminescence element. It is the display device used.

[0002]

2. Description of the Related Art An electroluminescent display (ELD) is used as a light emitting type electronic display device.
There is. Examples of the ELD constituent elements include an inorganic electroluminescent element and an organic electroluminescent element. The inorganic electroluminescent device is
Although it has been used as a flat light source, a high alternating voltage is required to drive a light emitting element. An organic electroluminescence device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and electrons and holes are injected into the light emitting layer to recombine to generate excitons. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several V to several tens of V. Therefore, it has a wide viewing angle and high visibility, and since it is a thin-film type complete solid-state element, it is attracting attention from the viewpoints of space saving, portability, and the like.

However, as an organic EL element for practical use in the future, it is desired to develop an organic EL element which emits light with high brightness efficiently and with lower power consumption.

Various organic EL devices have been reported so far. For example, Appl. Phys. Lett. , V
ol. 51, 913, or JP-A-59-1943.
93, a combination of a hole injection layer and an organic light emitting layer, a combination of a hole injection layer and an electron injection transport layer described in JP-A-63-295695, Jpn.
Journal of Applied Physic
s, vol. 127, No. No. 2, pp. 269-271, a combination of a hole transfer layer, a light emitting layer and an electron transfer layer is disclosed. However, a device with higher brightness is required, and further improvement in energy conversion efficiency and emission quantum efficiency is expected.

It has also been pointed out that the light emission life is short. The cause of such deterioration in luminance over time has not been completely clarified, but the electroluminescent element during light emission decomposes the organic compound itself that constitutes the thin film due to the light emitted by itself and the heat generated at that time, and It has been pointed out that the factors derived from the organic compound that is the organic EL device material, such as the crystallization of the organic compound in the above.

[0006] Further, at present, electron transport materials have little knowledge and, in combination with the use of antibonding orbitals, no useful high performance electron transport materials have been found for practical use. is there. For example, a research group at Kyushu University has a 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4 which is an oxadiazole derivative.
-Oxadiazole (t-BuPBD) and other oxadiazole dimer derivative 1,3-bis (4-t-butylphenyl-1,3,4-) having improved thin film stability
Oxadizolyl) biphenylene (OXD-1), 1,3
-Bis (4-t-butylphenyl-1,3,4-oxadizolyl) phenylene (OXD-7) (Jpn. JA
ppl. Phys. vol. 31 (1992), p. 1
812) is proposed. In addition, a research group at Yamagata University has produced a white light emitting device by using a triazole-based electron transport material having an excellent electron blocking property (Science, 3 March 1995, Vo.
l. 267, p. 1332). Furthermore, JP-A-5-33
1459 describes that a phenanthroline derivative is useful as an electron transport material.

However, the conventional electron transport material has a problem that the light emitting element is broken because the thin film forming ability is low and the crystallization easily occurs, and the element performance that can be practically used cannot be expressed.

As an organic electroluminescent material for solving these problems, in JP-A-9-87616, JP-A-9-194487, and JP-A-2000-186094, a compound containing a silicon atom in the molecule is used as a light emitting material or an electron transporting material. Although examples of use are described, it was not sufficient to achieve both emission efficiency and emission life.

On the other hand, a method has been reported in which the light emitting layer is composed of a host compound and a small amount of a phosphor to achieve improvement in light emitting efficiency. For example, Japanese Patent No. 3093
In Japanese Patent No. 796, a stilbene derivative, a distyrylarylene derivative or a trisstyrylarylene derivative is doped with a small amount of a phosphor to achieve improvement of emission brightness and prolongation of device life. A device having an organic light-emitting layer in which a trace amount of a phosphor is doped with a host compound of 8-hydroxyquinoline aluminum complex (Japanese Patent Laid-Open No. 63-2).
No. 64692), an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a quinacridone dye is doped therein (Japanese Patent Laid-Open Publication No. HEI 3-301).
No. 255190) is known. As mentioned above,
By doping the phosphor with high fluorescence quantum yield,
The emission brightness is improved as compared with the conventional device.

However, the light emission from the above-mentioned trace amount of the doped phosphor is the light emission from the excited singlet, and when the light emission from the excited singlet is used, the generation ratio of the singlet excitons and the triplet excitons is generated. Is 1: 3, the probability of generating luminescent excited species is 25%, and the light extraction efficiency is about 20%.
_Therefore , the limit of the external extraction quantum efficiency (η _ext ) is set to 5%. However, an organic EL device using phosphorescence emission from Princeton University to excited triplet has been reported (MA Baldo et al., Nature.
e, vol. 395, pp. 151-154 (1998))
Since then, research on materials exhibiting phosphorescence at room temperature has become active (for example, MA Baldoet a.
l. , Nature, Volume 403, No. 17, 750-75
3 pages (2000), US Pat. No. 6,097,147, etc.). When the excited triplet is used, the upper limit of the internal quantum efficiency becomes 100%, so that in principle, the luminous efficiency is up to 4 times higher than that of the excited singlet, and it is possible to obtain almost the same performance as a cold cathode tube. It can also be applied to applications and is drawing attention.

It is needless to say that the host when the phosphorescent compound is used as a dopant is required to have an emission maximum wavelength in a region shorter than the emission maximum wavelength of the phosphorescent compound, but other requirements should be satisfied. I understand that there are conditions.

The 10th Internet
nal Workshop on Inorganic
and Organic Electrolumine
Science (EL '00, Hamamatsu) has made some reports on phosphorescent compounds. For example, I
Kai et al. use a hole-transporting compound as a host for a phosphorescent compound. In addition, M. E. Tampson et al. Use various electron-transporting materials as a host of a phosphorescent compound by doping them with a novel iridium complex. Furthermore, Tsutsui et al. Obtained high luminous efficiency by introducing a hole blocking layer. The hole blocking layer is structurally the same as the electron transport layer used in a normal organic EL element, but its function is that of holes that leak from the light emitting layer to the cathode side rather than the electron transport function. It is named as a hole blocking layer because it has a strong function of blocking movement, and can be interpreted as a kind of electron transport layer.

Therefore, in the present application, the hole block layer is also referred to as an electron transport layer, and the material (hole blocker) used in that layer is also referred to as an electron transport material.

Regarding the host compound of the phosphorescent compound,
For example, C.I. Adachi et al. , Appl. P
hys. Lett. , 77, 904 (2000
However, it is necessary to take a new approach from the viewpoint of the properties required for the host compound to obtain a high-brightness organic electroluminescent device.

However, in any of the reports, it is the current situation that the structure capable of improving both the emission brightness of the device and the durability is not obtained.

[0016]

SUMMARY OF THE INVENTION Therefore, the present invention has been made for the purpose of improving the emission brightness and durability of the device by using a phenylpyridine compound having a specific structure. By using a phenylpyridine compound as a host compound for phosphorescence emission, or by using a phenylpyridine compound as an electron transport material (hole blocker), an organic electroluminescence device that achieves both improved emission brightness and durability It is intended to provide a long-life display device using the same, which has high emission brightness.

[0017]

The above objects of the present invention have been achieved by the following constitutions.

1. An organic electroluminescence device comprising at least one compound represented by the general formula (1).

2. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (2).

3. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (3).

4. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (4).

5. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (5).

6. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (6).

7. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (7).

8. 2. The organic electroluminescence device according to item 1, wherein the compound represented by the general formula (1) is a compound represented by the general formula (8).

9. The electron transport layer has the above general formula (1) to
An organic electroluminescence device comprising at least one compound selected from the compounds represented by (8).

10. The light emitting layer has the general formula (1) to
An organic electroluminescence device comprising at least one compound selected from the compounds represented by (8).

11. In an organic electroluminescent device having a light emitting layer containing a host compound and a phosphorescent compound, the host compound is represented by the general formula (1) to
An organic electroluminescence device comprising at least one compound selected from the compounds represented by (8).

12. 12. The organic electroluminescence device as described in 11 above, wherein the phosphorescent compound is an iridium compound, an osmium compound or a platinum compound.

13. 12. The organic electroluminescence device according to the above item 11, wherein the phosphorescent compound is an iridium compound.

14. A display device comprising the organic electroluminescence element according to any one of 1 to 13 above.

The present invention will be described in detail below. First, the compound represented by formula (1) will be described.

In the general formula (1), the n-valent linking group represented by Z is not particularly limited, but is preferably Z _{1 to} Z ₆ in the general formulas (2) to (7). It is a linking group represented.

In the general formula (1), R _{1 to} R ₈ each represent a hydrogen atom or a substituent, and the substituent is, for example, an alkyl group (eg, methyl group, ethyl group, i-group).
Propyl group, hydroxyethyl group, methoxymethyl group,
Trifluoromethyl group, t-butyl group, cyclopentyl group, cyclohexyl group, benzyl group, etc.), alkenyl group (for example, vinyl group, propenyl group, styryl group, etc.),
Alkynyl group (eg ethynyl group etc.), aryl group (eg phenyl group, naphthyl group, p-tolyl group, p
-Chlorophenyl group, etc.), an alkyloxy group (for example,
Methoxy group, ethoxy group, i-propoxy group, butoxy group etc.), aryloxy group (eg phenoxy group etc.), alkylthio group (eg methylthio group, ethylthio group, i-propylthio group etc.), arylthio group (eg, Phenylthio group etc.), halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom etc.), amino group (eg dimethylamino group, methylamino group, diphenylamino group etc.), cyano group, nitro group, hetero group A cyclic group (for example, a pyrrole group, a pyrrolidyl group, a pyrazolyl group,
Imidazolyl group, pyridyl group, benzimidazolyl group,
Benzothiazolyl group, benzoxazolyl group, etc.) and the like. As the aromatic group, the above aryl group and heteroaryl group (for example, a pyrrole group, a pyrazolyl group,
Imidazolyl group, pyridyl group, benzimidazolyl group,
Benzothiazolyl group, benzoxazolyl and the like). Adjacent substituents may be condensed with each other to form a ring.

In the above general formulas (2) to (7), R _a
To R _f each represent a hydrogen atom or a substituent, and specific examples thereof have the same meanings as R _{1 to} R ₈ .

In the above general formulas (1) to (7), Ar
The divalent arylene group represented by is a residue obtained by removing two hydrogen atoms or substituents from any position of any aromatic compound, and the arylene group is composed of a hydrocarbon. Or a heterocycle containing a heteroatom,
It may be condensed.

In the general formula (8), the m-valent arylene group represented by Ar ₁ is a residue obtained by removing m hydrogen atoms or substituents from any position of any aromatic compound. The arylene group may be composed of a hydrocarbon, a heterocycle containing a hetero atom, or a condensed ring.

Each of the compounds represented by the general formulas (1) to (8) according to the present invention is a compound having strong fluorescence in a solid state, has an excellent electroluminescent property, and is effectively used as a light emitting material. it can. In addition, since the excellent electron injecting property and electron transporting property from the metal electrode are very excellent, the compound according to the present invention is used as an electron in an element using another light emitting material or the compound according to the present invention as a light emitting material. When used as a transportation material or hole blocker, it exhibits excellent luminous efficiency.

Specific examples of the compounds represented by the general formulas (1) to (8) are listed below, but the invention is not limited thereto.

[0040]

[Chemical 21]

[0041]

[Chemical formula 22]

[0042]

[Chemical formula 23]

[0043]

[Chemical formula 24]

[0044]

[Chemical 25]

[0045]

[Chemical formula 26]

The above-mentioned compound according to the present invention can be easily synthesized according to a known synthetic method, but can be synthesized more easily by the synthetic route shown below.

[0047]

[Chemical 27]

The above reaction is based on Organic Letter magazine, Vo.
l. 3, No. 16, p2579-2581 (2001
Year).

Further, the inventors of the present invention have conducted extensive studies on the host compound of the phosphorescent compound, and as a result, when the organic electroluminescence device was produced by using the phenylpyridine compound according to the present invention as the host compound, It has been found that the emission brightness and lifetime of the device are improved.

The host compound in the present invention is a compound having the highest mixing ratio (mass ratio) in the light emitting layer composed of two or more kinds of compounds, and the other compounds are called dopant compounds. For example, the light emitting layer is composed of two kinds of compound A and compound B, and the mixing ratio thereof is A: B = 10:
If it is 90, compound A is a dopant compound and compound B is a host compound. Furthermore, if the light emitting layer is composed of three kinds of compound A, compound B and compound C, and the mixing ratio is A: B: C = 5: 10: 85, compound A and compound B are dopant compounds, Compound C is the host compound.

From the above definition, the phosphorescent compound according to the present invention is a kind of dopant compound.

The phosphorescent compound according to the present invention is a compound in which light emission from excited triplet is observed, and the phosphorescent quantum yield is a compound of 0.001 or more at 25 ° C.
It is preferably 0.01 or more. More preferably 0.1
That is all.

The above-mentioned phosphorescence quantum yield can be measured by the method described on page 398 of Spectroscopy II of 4th edition Experimental Chemistry Course 7 (1992 edition, Maruzen). The phosphorescence quantum yield in a solution can be measured using various solvents, and the phosphorescent compound used in the present invention may be any phosphorescent compound as long as the above phosphorescence quantum yield is achieved.

A complex compound containing a metal of Group VIII in the periodic table of elements is preferable, and more preferably,
It is an iridium, aluminum, or platinum complex compound, more preferably an iridium complex compound.

Specific examples of the phosphorescent compound used in the present invention are shown below, but the invention is not limited thereto. These compounds are described, for example, in Inorg. Che
m. 40, 1704-1711, and the like.

[0056]

[Chemical 28]

[0057]

[Chemical 29]

[0058]

[Chemical 30]

In another embodiment, in addition to the host compound and the phosphorescent compound, at least one fluorescent compound having a fluorescence maximum wavelength in a region longer than the maximum wavelength of light emitted from the phosphorescent compound is used. It may be included. in this case,
By the energy transfer from the host compound and the phosphorescent compound, electroluminescence as an organic EL device can obtain light emission from the fluorescent compound. Preferred as the fluorescent compound is
It has a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 0.1 or more, and particularly preferably 0.3 or more.
Specifically, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squaryl dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes , Polythiophene dyes, rare earth complex phosphors, and the like. The fluorescence quantum yield as used herein can also be measured by the method described on page 362 (1992, Maruzen) of Spectroscopy II of the Fourth Edition Experimental Chemistry Course 7.

The constituent elements of the organic electroluminescent element of the present invention will be described below.

In the present invention, preferred specific examples of the layer structure of the organic EL element are shown below, but the present invention is not limited thereto.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / hole blocking Layer / electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer /
Hole blocking layer / electron transport layer / cathode buffer layer / cathode As the anode in the organic EL device, those having a high work function (4 eV or more) metal, alloy, electrically conductive compound and a mixture thereof as an electrode substance are preferable. Used. Specific examples of such an electrode material include metals such as Au, CuI, indium tin oxide (ITO), and Sn.
Conductive transparent materials such as O ₂ and ZnO are mentioned. Also,
An amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. The anode may be formed into a thin film by a method such as vapor deposition or sputtering of these electrode substances, and a pattern of a desired shape may be formed by a photolithography method, or if pattern accuracy is not required (100 μm or more). Pattern), a pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material. When the emitted light is taken out from this anode, it is desirable that the transmittance is higher than 10%, and the sheet resistance as the anode is several hundred Ω /
□ The following is preferable. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

On the other hand, as the cathode, a metal having a low work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, or a mixture thereof is used as an electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum /
Examples thereof include aluminum oxide (Al ₂ O ₃ ) mixture, indium, lithium / aluminum mixture, and rare earth metal. Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than that, from the viewpoint of electron injecting property and durability against oxidation, for example,
Magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium /
Aluminum mixtures, aluminum and the like are suitable. The cathode can be produced by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. The sheet resistance of the cathode is several hundred Ω / □
The following is preferred, and the film thickness is usually selected in the range of 10 to 1000 nm, preferably 50 to 200 nm. In order to transmit the emitted light, it is convenient that either the anode or the cathode of the organic EL element is transparent or semi-transparent and the emission brightness is improved.

Next, an injection layer, a hole transport layer, an electron transport layer,
The light emitting layer and the like will be described. The injection layer is provided as necessary, and has an electron injection layer and a hole injection layer, and is present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above. You may let me.

The injection layer is a layer provided between the electrode and the organic layer for the purpose of lowering the driving voltage and improving the light emission brightness, and refers to "an organic EL element and its industrial front line (November 30, 1998).
Nihon TS Co., Ltd.) ", Volume 2, Chapter 2," Electrode Materials "(Pages 123-166),
There are a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

The anode buffer layer (hole injection layer) is described in JP-A Nos. 9-45479, 9-260062 and 8-2.
The details are also described in 88069 and the like, and specific examples thereof include a phthalocyanine buffer layer represented by copper phthalocyanine, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, polyaniline (emeraldine) and polythiophene. And a polymer buffer layer using a conductive polymer.

The cathode buffer layer (electron injection layer) is described in JP-A Nos. 6-325871, 9-17574 and 10-.
The details are also described in No. 74586 and the like, specifically, metal buffer layers typified by strontium and aluminum, alkali metal compound buffer layers typified by lithium fluoride, and alkali typified by magnesium fluoride. Examples thereof include an earth metal compound buffer layer and an oxide buffer layer typified by aluminum oxide.

The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 100 nm, although it depends on the material.

As described above, the blocking layer is provided as necessary in addition to the basic constituent layers of the organic compound thin film. For example, JP-A-11-204258 and 11-2.
There is a hole blocking (hole blocking) layer described on page 237 of No. 04359 and "organic EL device and its forefront of industrialization" (published on Nov. 30, 1998, NTS Co., Ltd.).

The hole blocking layer is an electron transporting layer in a broad sense, and is made of a material having a function of transporting electrons and having a significantly small ability to transport holes, and is capable of blocking holes while transporting electrons. Can improve the recombination probability of electrons and holes.

On the other hand, the electron blocking layer is, in a broad sense, a hole transporting layer, and is made of a material having a function of transporting holes and having a very small ability to transport electrons, and blocks electrons while transporting holes. By doing so, the recombination probability of electrons and holes can be improved.

The hole transport layer is made of a material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer.

The hole transport layer and the electron transport layer can be provided as a single layer or a plurality of layers. The light-emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron-transporting layer, or the hole-transporting layer. The light-emitting portion is adjacent to the light-emitting layer even in the light-emitting layer. It may be the interface with the layer.

The material used for the light emitting layer (hereinafter referred to as the light emitting material) is preferably an organic compound or complex which emits fluorescence or phosphorescence, and is appropriately selected from the known materials used for the light emitting layer of organic EL devices. It can be selected and used. Such a light emitting material is mainly an organic compound, and depending on a desired color tone, for example, Macromol. S
ynth. , 125, pp. 17-25, and the like.

The light emitting material may have a hole transporting function and an electron transporting function in addition to the light emitting performance, and most of the hole transporting material and the electron transporting material can also be used as the light emitting material.

The light emitting material may be a polymer material such as p-polyphenylene vinylene or polyfluorene, and a polymer material in which the light emitting material is introduced into a polymer chain or the light emitting material is a polymer main chain. May be used.

This light emitting layer can be formed by forming the above compound by a known thin film forming method such as a vacuum vapor deposition method, a spin coating method, a casting method and an LB method.
The thickness of the light emitting layer is not particularly limited, but is usually 5n.
It is selected in the range of m to 5 μm. The light emitting layer may have a single layer structure composed of one or more kinds of these light emitting materials, or a laminated structure composed of a plurality of layers having the same composition or different compositions. In a preferred embodiment of the organic EL device of the present invention, the light emitting layer is composed of two or more kinds of materials,
At least one of them is the compound according to the present invention.

Further, this light emitting layer is disclosed in JP-A-57-517.
As described in Japanese Patent Publication No. 81-81, after the light emitting material is dissolved in a solvent together with a binder such as a resin to form a solution,
This can be formed into a thin film by a spin coating method or the like. The thickness of the light emitting layer thus formed is not particularly limited and may be appropriately selected depending on the situation, but is usually in the range of 5 nm to 5 μm.

As described above, when there are two or more kinds of materials for the light emitting layer, the main component is called host and the other components are called dopant. The mixing ratio of the dopant is preferably 0.1% or more and less than 15% by mass.

The host compound of the light emitting layer is preferably an organic compound or complex, and in the present invention, the maximum fluorescence wavelength is preferably shorter than that of the dopant.

As the host compound, any of known compounds used for organic EL devices can be selected and used, and most of the hole-transporting materials and electron-transporting materials described later are used as the light-emitting layer host compound. Can also be used as

A polymer material such as polyvinylcarbazole or polyfluorene may be used, and a polymer material in which the host compound is introduced into the polymer chain or the host compound is used as a polymer main chain may be used. .

As the host compound, a compound having a hole transporting ability and an electron transporting ability and having a high Tg (glass transition temperature) is preferable.

The hole transport layer is made of a material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer may be a single layer or a plurality of layers.

The hole transport material is not particularly limited,
Conventionally, in an optical transmission material, an arbitrary material is selected and used from materials conventionally used as charge injection / transport materials for holes and known materials used in hole injection layers and hole transport layers of EL elements. be able to.

The hole transport material has any of hole injection or transport and electron barrier properties, and may be either an organic substance or an inorganic substance. For example, triazole derivative, oxadiazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, oxazole derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative. Examples thereof include derivatives, silazane derivatives, aniline-based copolymers, and conductive polymer oligomers, especially thiophene oligomers.

As the hole transport material, the above-mentioned materials can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds are N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'.
-Diphenyl-N, N'-bis (3-methylphenyl)
-[1,1'-biphenyl] -4,4'-diamine (T
PD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-
Tetra-p-tolyl-4,4'-diaminobiphenyl;
1,1-bis (4-di-p-tolylaminophenyl)-
4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-
Di-p-tolylaminophenyl) phenylmethane; N,
N'-diphenyl-N, N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ',
N'-Tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) ) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N,
N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and further described in US Pat. No. 5,061,569. Having two fused aromatic rings in the molecule, such as 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308.
No. 688, three triphenylamine units are linked in a starburst type 4,4 ′,
4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) and the like can be mentioned.

Further, it is also possible to use a polymer material in which these materials are introduced into the polymer chain, or where these materials are used as the polymer main chain.

Inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injecting material and the hole transporting material.

Further, in the present invention, the hole transporting material of the hole transporting layer is preferably a compound having a shorter maximum fluorescence wavelength and a higher Tg than the compound used for the light emitting layer.

This hole transport layer contains the above hole transport material,
For example, it can be formed by forming a thin film by a known method such as a vacuum vapor deposition method, a spin coating method, a casting method, an inkjet method, an LB method. The thickness of the hole transport layer is not particularly limited, but is usually 5 to 5000 n.
It is about m. The hole transport layer may have a single-layer structure composed of one or more of the above materials.

The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, the electron injection layer and the hole blocking layer are also included in the electron transport layer. The electron transport layer may be a single layer or a plurality of layers.

Further, the electron-transporting layer used as required may have a function of transmitting the electrons injected from the cathode to the light-emitting layer, and the material thereof is any of conventionally known compounds. One can be selected and used.

Materials used for this electron transport layer (hereinafter, referred to as
Examples of the electron transport material) include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic acid anhydrides such as naphthaleneperylene, carbodiimides, fluorenylidene methane derivatives, anthraquinodimethane and Examples thereof include anthrone derivative and oxadiazole derivative. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as the electron transport material.

Further, it is also possible to use a polymer material in which these materials are introduced into a polymer chain or where these materials are used as a polymer main chain.

Further, metal complexes of 8-quinolinol derivatives, for example, tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-).
Quinolinol) aluminum, tris (2-methyl-8)
-Quinolinol) aluminum, tris (5-methyl-)
8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metal of these metal complexes is In, Mg, Cu, Ca, Sn, Ga or Pb.
The metal complex replaced with can also be used as an electron transport material. In addition, metal-free or metal phthalocyanine, or those whose terminal is substituted with an alkyl group, a sulfonic acid group, or the like can be preferably used as the electron transport material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as the electron transporting material, and like the hole injecting layer and the hole transporting layer, it is an inorganic material such as n-type-Si or n-type-SiC. Semiconductors can also be used as electron transport materials.

As with the compound used in the hole transport layer, the compound used in the electron transport layer is a compound having a shorter maximum fluorescence wavelength and a higher Tg than the compound used in the light emitting layer. preferable.

The substrate preferably used in the organic EL device of the present invention is not particularly limited in the kind of glass, plastic, etc., and is not particularly limited as long as it is transparent.
As the substrate preferably used, for example, glass, quartz,
A light transmissive resin film can be mentioned. A particularly preferable substrate is a resin film that can give flexibility to the organic EL element.

Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide, polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide,
Polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (C
Examples thereof include a film made of AP) and the like.

An inorganic or organic coating or a hybrid coating of both may be formed on the surface of the resin film.

In the organic electroluminescent device of the present invention, the efficiency of extracting light emitted to the outside at room temperature is 1
% Or more, and more preferably 2% or more. Here, the external extraction quantum efficiency (%) = organic E
The number of photons emitted outside the L element / the number of electrons flown into the organic EL element × 100.

Further, a hue improving filter such as a color filter may be used in combination. The display device of the present invention is composed of at least two kinds of organic EL elements having different emission maximum wavelengths, and a suitable example for producing the organic EL element will be described. As an example, a method for producing an organic EL device consisting of anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described. First, on an appropriate substrate,
A thin film of the desired electrode material, eg, the anode material,
It is formed by a method such as vapor deposition or sputtering to have a film thickness of less than or equal to μm, preferably 10 to 200 nm,
Make an anode. Next, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, which are element materials, are formed thereon.
An organic compound thin film for the hole blocking layer is formed.

As a method for thinning the organic compound thin film, there are spin coating method, casting method, ink jet method, vapor deposition method, printing method and the like as described above, but it is easy to obtain a uniform film and pinholes are not formed. Because it is difficult to generate,
A vacuum deposition method or a spin coating method is particularly preferable. Further, a different film forming method may be applied for each layer. When the vapor deposition method is used for film formation, the vapor deposition conditions generally differ from the boat heating temperature of 50 to 4 although it varies depending on the type of compound used and the like.
50 ° C, vacuum degree 10 ^-6 to 10 ^-2 Pa, vapor deposition rate 0.01
˜50 nm / sec, substrate temperature −50 to 300 ° C., film thickness 0.
It is desirable to appropriately select in the range of 1 nm to 5 μm.

After forming these layers, a thin film made of a substance for the cathode is formed thereon and has a thickness of 1 μm or less, preferably 50 to 200 n.
A desired organic EL element can be obtained by forming a film having a thickness in the range of m by a method such as vapor deposition or sputtering and providing a cathode. In the production of this organic EL element, it is preferable to consistently produce from the hole injection layer to the cathode by one-time evacuation, but it is also possible to take out in the middle and apply a different film forming method. In that case, it is necessary to consider that the work should be performed in a dry inert gas atmosphere.

In the display device of the present invention, since the shadow mask is provided only when the light emitting layer is formed and the other layers are common, patterning of the shadow mask or the like is unnecessary, and the vapor deposition method, the cast method, the spin coating method, the ink jet method are formed on one surface. The film can be formed by a method, a printing method, or the like.

When patterning only the light emitting layer, the method is not limited, but the vapor deposition method, the ink jet method and the printing method are preferable. When the vapor deposition method is used, patterning using a shadow mask is preferable.

It is also possible to reverse the order of production to produce a cathode, an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, a hole injection layer and an anode in this order.

When a DC voltage is applied to the thus obtained multicolor display device, the anode is + and the cathode is-.
When a voltage of about 2 to 40 V is applied as the polarity of, light emission can be observed. Moreover, even if a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the − state. The waveform of the alternating current applied may be arbitrary.

The display device of the present invention can be used as a display device, a display, and various light emitting sources. By using three kinds of organic EL elements of blue, red, and green light emission in a display device and a display, full-color display is possible.

Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a teletext display, and an information display in a car. In particular, it may be used as a display device for reproducing still images and moving images,
When used as a display device for moving image reproduction, either a simple matrix (passive matrix) system or an active matrix system may be used as a driving system.

As the light emission source, home lighting, interior lighting, backlight for clock and liquid crystal, billboard advertisement, traffic light,
Examples thereof include a light source for an optical storage medium, a light source for an electrophotographic copying machine, a light source for an optical communication processor, a light source for an optical sensor, and the like, but are not limited thereto.

Further, the organic EL element of the present invention may be used as an organic EL element having a resonator structure. Examples of the purpose of using the organic EL element having such a resonator structure include, but are not limited to, a light source for an optical storage medium, a light source for an electrophotographic copying machine, a light source for an optical communication processor, a light source for an optical sensor. Not something to do. Moreover, you may use it for the said use by making a laser oscillation.

[0114]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 << Preparation of Organic EL Element >> ITO on glass as an anode
After patterning was performed on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) on which (indium tin oxide) was formed to a thickness of 150 nm, the transparent support substrate provided with this ITO transparent electrode was ultrasonicated with i-propyl alcohol. After cleaning and drying with dry nitrogen gas, UV ozone cleaning was performed for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD was put in a resistance heating boat made of molybdenum, and 200 mg of Comparative Compound 1 was put in another resistance heating boat made of molybdenum. 200 mg of bathocuproine (BCP) was put in a resistance heating boat made of molybdenum, and 200 mg of Alq ₃ was put in another resistance heating boat made of molybdenum, which was attached to a vacuum vapor deposition apparatus.

Next, the vacuum chamber was decompressed to 4 × 10 ⁻⁴ Pa, and the heating boat containing α-NPD was energized to heat it, and the transparent support substrate was deposited at a deposition rate of 0.1 to 0.3 nm / sec. Was evaporated to a thickness of 50 nm to form a hole transport layer.
The substrate temperature during vapor deposition was room temperature.

Next, the heating boat containing the comparative compound 1 was energized and heated, and the vapor deposition rate was 0.1 to 0.3 nm /
A light emitting layer having a film thickness of 30 nm was provided in sec. Furthermore, BCP
The heating boat containing the is heated by energizing, the film thickness 10n
m hole blocking layer was provided. Further, the heating boat containing Alq ₃ is energized and heated, and the deposition rate is 0.1 to 0.3.
An electron transport layer having a film thickness of 20 nm was provided at nm / sec.

Next, the vacuum chamber was opened, and a rectangular perforated mask made of stainless steel was placed on the electron injection layer, while 3 g of magnesium was placed in a resistance heating boat made of molybdenum.
0.5 g of silver was placed in a tungsten vapor deposition basket, the vacuum chamber was decompressed again to 2 × 10 ⁻⁴ Pa, and a boat containing magnesium was energized to deposit a vapor deposition rate of 1.5 to 2.
Magnesium was vapor-deposited at 0 nm / sec. At this time, the silver basket is heated at the same time, and the deposition rate is 0.1 nm / s.
Organic EL element OLED1-1 for comparison shown in Table 1 was prepared by vapor-depositing silver by ec to obtain a cathode made of the mixture of magnesium and silver.

Then, the above organic EL element OLED1-1
In the same manner as described above, except that the comparative compound 1 was changed to each compound shown in Table 1, and the organic EL device OLED1
-2-1-10 was produced. The emission color of each organic EL element was from blue to green.

[0120]

[Chemical 31]

[0121]

[Chemical 32]

<< Evaluation of Organic EL Element >> Each of the organic EL elements produced as described above was subjected to 1 hour in a dry nitrogen gas atmosphere at a temperature of 23 ° C.
Continuous lighting was carried out by applying a 0 V DC voltage, and the emission brightness (cd / m ² ) at the start of lighting and the time at which the brightness was reduced to half were measured. The light emission brightness is represented by a relative value when the light emission brightness of the organic EL element OLED1-1 is 100, and the time when the brightness is reduced to half is the organic electroluminescence element OLED1.
It was expressed as a relative value with the time at which the emission luminance of -1 was halved as 100. The emission brightness (cd / m ² ) was measured using CS-1000 manufactured by Minolta.

Table 1 shows the results obtained as described above.

[0124]

[Table 1]

As is clear from Table 1, in the organic EL device using the compound according to the present invention, the emission brightness at the start of lighting and the time until the emission brightness is reduced to half are improved as compared with the comparative example. I understand.

Example 2 The same as in Example 1 except that a light emitting layer having a film thickness of 30 nm, which was obtained by evaporating the exemplary compound 24 of the present invention and DCM2 at a mass ratio of 100: 1, was used. Then, the organic electroluminescence element OLED2-
1 was produced. The organic EL element OLED2- produced above
When a direct current voltage of 10 V was applied to the sample No. 1 in a dry nitrogen gas atmosphere at a temperature of 23 degrees, red light emission was obtained.

In the production of the organic electroluminescence element OLED2-1, DCM2 is replaced by Qd2.
Alternatively, by substituting BCzVBi, green or blue light emission was obtained, respectively.

[0128]

[Chemical 33]

Example 3 << Fabrication of Organic EL Element >> ITO on glass as an anode
After patterning was performed on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) on which (indium tin oxide) was formed to a thickness of 150 nm, the transparent support substrate provided with this ITO transparent electrode was ultrasonicated with i-propyl alcohol. After cleaning and drying with dry nitrogen gas, UV ozone cleaning was performed for 5 minutes. This transparent supporting substrate was fixed to a substrate holder of a commercially available vacuum evaporation system, while 200 mg of m-MTDATA was put in a resistance heating boat made of molybdenum and 200 mg of DPVBi was put in another resistance heating boat made of molybdenum. 200 BCP for molybdenum resistance heating boat
mg was put and it attached to the vacuum evaporation system.

Next, the vacuum chamber was evacuated to 4 × 10 ⁻⁴ Pa, and then the heating boat containing m-MTDATA was energized to heat it, and the transparent support substrate was deposited at a deposition rate of 0.1 to 0.3 nm / sec. Vapor-deposited with a film thickness of 25 nm, and then DPVB
The heating boat containing i is energized and heated to deposit a film having a thickness of 20 nm at a deposition rate of 0.1 to 0.3 nm / sec,
A light emitting layer was provided. The substrate temperature during vapor deposition was room temperature.

Next, the heating boat containing the BCP is energized and heated, and the vapor deposition rate is 0.1 to 0.3 nm / sec.
Then, an electron transport layer having a film thickness of 30 nm was provided.

Then, the vacuum chamber was opened, a rectangular perforated mask made of stainless steel was placed on the electron transport layer, while 3 g of magnesium was placed in a molybdenum resistance heating boat,
0.5 g of silver was placed in a tungsten vapor deposition basket, the vacuum chamber was decompressed again to 2 × 10 ⁻⁴ Pa, and a boat containing magnesium was energized to deposit a vapor deposition rate of 1.5 to 2.
Magnesium is vapor-deposited at 0 nm / sec, and at the same time, a silver basket is heated at a vapor deposition rate of 0.1 nm / se.
The organic EL element OLE for comparison was prepared by vapor-depositing silver by using c to obtain a cathode made of the mixture of magnesium and silver.
D3-1 was produced.

In the production of the organic EL device OLED3-1, the organic electroluminescence device OLE was prepared in the same manner except that BCP was replaced with each compound shown in Table 2.
D3-2-12 was produced.

[0134]

[Chemical 34]

<< Evaluation of Organic EL Element >> Each of the organic EL elements prepared as described above was subjected to 1
Continuous lighting was carried out by applying a 0 V DC voltage, and the emission brightness (cd / m ² ) at the start of lighting and the time at which the brightness was reduced to half were measured. The light emission brightness is represented by a relative value when the light emission brightness of the organic EL element OLED3-1 is 100, and the time when the brightness is halved is the organic electroluminescence element OLED3.
It was expressed as a relative value with the time at which the emission luminance of -1 was halved as 100. Luminance (cd / m ² ) is Minolta CS-
It was measured using 1000. The emission color of all the organic EL devices was blue.

[0136]

[Table 2]

As is clear from Table 2, the organic EL device using the compound according to the present invention has improved emission luminance at the start of lighting, emission efficiency and the time required for reducing the luminance by half, as compared with the comparative example. In particular, it can be seen that the time required for the brightness to decrease to half is improved.

Example 4 The cathode of the organic EL element OLED3-11 manufactured in Example 3 was replaced with Al, and lithium fluoride was vapor-deposited to a film thickness of 0.5 nm between the electron transport layer and the cathode to form the cathode. An organic EL device OLE was similarly prepared except that a buffer layer was provided.
D4-1 was produced.

The organic EL element OLED4-1 produced above
The emission luminance (cd / m ² ) at the start of lighting and the half-decay time of the luminance were measured in the same manner as in Example 3 to find that the organic electroluminescent device O
Relative comparison with the LED 3-1 revealed that the emission luminance 214 and the time 405 for halving the luminance were 405. In addition, the organic EL element OL
As for the EDs 3-3 to 10 and 3-12, as a result of introducing the cathode buffer layer in the same manner as in the organic EL element OLED4-1, it was confirmed that the effect was further exerted.

Example 5 In the light emitting layer of each organic EL element produced in Example 3,
From DPVBi Alq ₃ or Alq ₃ and DCM respectively
Each organic electroluminescence device was prepared in the same manner except that 2 was changed to a light emitting layer vapor-deposited at a mass ratio of 100: 1, and the light emission luminance at the start of lighting (cd /
m ² ) and the time required for the luminance to decrease by half were measured. As a result, as in Example 3, the organic EL device using the compound according to the present invention in the electron transport layer was compared with Comparative Example (Organic EL Device 3-
1, 3-2), the emission luminance at the start of lighting (cd /
m ² ), and improvement in the time required for the brightness to decrease by half were confirmed.

When Alq ₃ was used for the light emitting layer, green light emission was obtained, and in the light emitting layer in which Alq ₃ and DCM2 were co-evaporated at 100: 1, red light emission was obtained.

Example 6 << Preparation of Organic EL Element >> Organic EL Element OLED6-1
6-8 was produced according to the method described below.

As the anode, 100 mm × 100 mm × 1.
After patterning was performed on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) in which ITO (Indium Tin Oxide) was formed in a film thickness of 150 nm on a 1 mm glass substrate, this I
The transparent supporting substrate provided with the TO transparent electrode is ultrasonically cleaned with isopropyl alcohol and dried with dry nitrogen gas, and then U
V ozone cleaning was performed for 5 minutes.

This transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation system, while 200 mg of α-NPD was put in a resistance heating boat made of molybdenum and 200 mg of CBP was put in another resistance heating boat made of molybdenum. In another molybdenum resistance heating boat, bathocuproine (BC
P) in an amount of 200 mg and another compound molybdenum resistance heating boat in which 100 mg of the exemplified compound Ir-1 (phosphorescent compound) is placed.
Put it into another molybdenum resistance heating boat and Alq
200 mg of ₃ was put and attached to a vacuum vapor deposition apparatus.

Then, after depressurizing the vacuum chamber to 4 × 10 ^-4 Pa, the heating boat containing α-NPD was energized for heating, and vapor deposition was carried out on the transparent supporting substrate at a vapor deposition rate of 0.1 nm / sec. A hole transport layer having a film thickness of 45 nm was provided. further,
The heating boat containing CBP and Ir-1 is energized and heated, and vapor deposition rates of 0.1 nm / sec and 0.01, respectively.
A film thickness of 20 by co-evaporating on the hole transport layer at nm / sec.
nm emission layer was provided. The substrate temperature during vapor deposition was room temperature. Further, the heating boat containing BCP is energized and heated, and is vapor-deposited on the light-emitting layer at a vapor deposition rate of 0.1 nm / sec to provide an electron-transporting layer having a film thickness of 10 nm and also serving as a hole blocking layer. It was On top of that, the heating boat containing Alq ₃ is further energized and heated, and the vapor deposition rate is 0.
An electron injection layer having a thickness of 40 nm was further provided by vapor deposition on the electron transport layer at 1 nm / sec. The substrate temperature during vapor deposition was room temperature.

Next, LiF was deposited to a film thickness of 0.5 nm and A
l is vapor-deposited with a film thickness of 110 nm to form a cathode,
Element OLED6-1 was produced.

In the production of the above organic EL element OLED6-1, instead of CBP as the host compound of the light emitting layer,
Except that each compound shown in Table 3 was used,
Organic EL elements OLED6-2 to 6-12 were produced.

[0148]

[Chemical 35]

<< Evaluation of Organic EL Element >> With respect to the organic EL elements OLED6-1 to 6-12 produced as described above, the emission luminance and the emission lifetime were evaluated. Each organic EL device was measured at 23 ° C. under a dry nitrogen gas atmosphere and at the time of applying a DC voltage of 9 V, the emission brightness and the half-life of the brightness (emission life) were measured. The light emission luminance is represented by a relative value when the light emission luminance of the organic EL element OLED6-1 is 100, and the time for which the luminance is reduced by half is also represented by a relative value when the organic EL element OLED6-1 is 100. Is shown in Table 3. Regarding the emission brightness (cd / m ² ), Minolta CS-1
000 was used for measurement. In each organic EL element, a current started to flow at an initial drive voltage of 3 V, and green emission was emitted from the phosphorescent compound that is the dopant of the light emitting layer.

[0150]

[Table 3]

As is clear from Table 3, the organic EL device using the compound according to the present invention as a host compound has a higher emission brightness and a longer emission life as compared with the comparative example. We were able to confirm that it was useful.

Further, in each of the organic EL devices prepared above, the exemplified compound Ir- was used instead of the phosphorescent compound Ir-1.
11 or Ir-9 was used to produce each organic EL element, and the same evaluation was performed. As a result, the same effect as above was obtained. A device using the exemplified compound Ir-11 emitted blue light, and a device using the exemplified compound Ir-9 emitted red light.

Example 7 << Fabrication of Organic EL Element >> Organic E fabricated in the above Example 6
In the L element OLED 6-1, B used in the electron transport layer
Organic EL elements OLED7-1 to 7-1 were produced in the same manner except that CP was changed to each compound shown in Table 4.

<< Evaluation of Organic EL Element >> With respect to the organic EL elements OLED7-1 to 7-1-11 produced above and the organic EL element OLED6-1 produced in Example 6, the emission luminance and the emission lifetime were evaluated. Each organic EL element was measured at 23 ° C. under a dry nitrogen gas atmosphere and at the time when a DC voltage of 9 V was applied, the emission luminance and the half-life time of the luminance. The emission brightness is 100 times that of the organic EL element OLED6-1.
It is expressed as a relative value when the
The L element OLED 6-1 was expressed as a relative value when 100 was set, and the obtained results are shown in Table 4. The emission brightness (c
d / m ² ) was measured using CS-1000 manufactured by Minolta, and the obtained results are shown in Table 4. In each organic EL element, a current started to flow at an initial drive voltage of 3 V, and green emission was emitted from the phosphorescent compound that is the dopant of the light emitting layer.

[0155]

[Table 4]

As is clear from Table 4, each organic EL device using the compound according to the present invention in the electron transport layer (hole blocking layer) has higher emission brightness and longer emission life than the comparative examples. Therefore, it was found that the organic EL device was very useful.

Furthermore, each organic EL element 7-1 produced as described above
~ 7-11, instead of the phosphorescent compound Ir-1,
Each organic EL element was produced using the exemplified compound Ir-11 or Ir-9, and the same evaluation was performed. As a result, the same effect as described above was obtained. A device using the exemplified compound Ir-11 emitted blue light, and a device using the exemplified compound Ir-9 emitted red light.

Example 8 The active matrix full-color display device shown in FIG. 1 was prepared by arranging the red, green, and blue light emitting organic electroluminescent elements produced in Example 6 side by side on the same substrate.

FIG. 1 shows only a schematic view of the display portion of the manufactured full-color display device. That is, on the same substrate, a wiring portion including a plurality of scanning lines 5 and data lines 6 and a plurality of pixels 3 arranged in parallel (pixels whose emission color is a red region, a green region pixel, a blue region pixel, etc.) are arranged. The scanning lines 5 and the plurality of data lines 6 of the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern, and the pixels 3 are located at the orthogonal positions.
(Not shown in detail). The plurality of pixels 3
Are driven by an active matrix method in which an organic EL element corresponding to each emission color, a switching transistor which is an active element, and a drive transistor are provided, and when a scanning signal is applied from the scanning line 5, the data line is driven. An image data signal is received from 6 and light is emitted according to the received image data. In this way, each red, green,
Full-color display is possible by appropriately arranging blue pixels in parallel. FIG. 2 is a circuit diagram for one pixel.

By driving the above-mentioned full-color display device, a clear full-color moving image display with high brightness was obtained.

[0161]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to improve the emission brightness and durability of a device by using a phenylpyridine compound having a specific structure, and use the phenylpyridine compound as a host compound for phosphorescent emission, or By using a phenylpyridine compound as an electron transport material (hole blocker), it is possible to provide an organic electroluminescence device having both improved emission brightness and durability and a display device using the same, which has high emission brightness and has a long life. I was able to.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a display device including an organic EL element of the present invention.

FIG. 2 is a circuit diagram showing an example of a circuit per image of the organic EL element of the present invention.

[Explanation of symbols]

1 glass substrate 2 wiring section 3 pixels 5 scan lines 6 data lines 7 power line 10 Organic electroluminescence device 11 switching transistors 12 drive transistor 13 capacitors 101 display

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 11/06 660 C09K 11/06 660 690 690 H05B 33/14 H05B 33/14 B (72) Inventor Inoue Sachio 3-9-18, Kunimi, Aoba-ku, Sendai-shi, Miyagi Prefecture (72) Inventor Shuichi Oi 8-6-10, Nagamachi, Taihaku-ku, Sendai-shi, Miyagi Prefecture (72) Shoichi Takayama 4 Yawata, Aoba-ku, Sendai-shi, Miyagi Prefecture 7th-5th F-term (reference) 3K007 AB02 AB11 DB03

Claims (14)

[Claims] 1. An organic electroluminescence device comprising at least one compound represented by the following general formula (1). [Chemical 1] [In the formula, Z represents an n-valent linking group or a simple bond,
Ar represents a divalent arylene group, and R _{1 to} R ₈ each represent a hydrogen atom or a substituent. n represents an integer of 2 or more and 6 or less. Among R _{1 to} R ₈ , adjacent substituents may be condensed with each other to form a ring. ] 2. The compound represented by the general formula (1) is
It is a compound represented by the following general formula (2), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 2] [In the formula, Z ₁ is And n represents a substituent of 2 or more and 6 or less. At least two of R _{a to} R _e are And a plurality of the substituents may be the same or different. Of R _{a to} R _e , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent, and adjacent substituents may be condensed with each other to form a ring. Ar represents a divalent arylene group, R _{1 to} R ₈
Each represents a hydrogen atom or a substituent. Of R _{1 to} R ₈ ,
Adjacent substituents may be condensed with each other to form a ring. ] 3. The compound represented by the general formula (1) is
It is a compound represented by the following general formula (3), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 5] [In the formula, Z ₂ is And n represents a substituent of 2 or more and 6 or less. At least two of R _{a to} R _f are And a plurality of the substituents may be the same or different. Of R _{a to} R _f , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent, and adjacent substituents may be condensed with each other to form a ring. Ar represents a divalent arylene group, R _{1 to} R ₈
Each represents a hydrogen atom or a substituent. Of R _{1 to} R ₈ ,
Adjacent substituents may be condensed with each other to form a ring. ] 4. The compound represented by the general formula (1) is
It is a compound represented by the following general formula (4), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 8] [In the formula, Z ₃ is And n represents a substituent of 2 or more and 6 or less. At least two of R _{a to} R _f are And a plurality of the substituents may be the same or different. Of R _{a to} R _f , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent, and adjacent substituents may be condensed with each other to form a ring. Ar represents a divalent arylene group, R _{1 to} R ₈
Each represents a hydrogen atom or a substituent. Of R _{1 to} R ₈ ,
Adjacent substituents may be condensed with each other to form a ring. ] 5. The compound represented by the general formula (1),
It is a compound represented by the following general formula (5), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 11] [In the formula, Z ₄ is And n represents 2 or 3. At least two of R _{a to} R _c are And a plurality of the substituents may be the same or different. Of R _{a to} R _c , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent. Further, Ar represents a divalent arylene group, and R _{1 to} R ₈ each represent a hydrogen atom or a substituent. Among R _{1 to} R ₈ , adjacent substituents may be condensed with each other to form a ring. ] 6. The compound represented by the general formula (1):
It is a compound represented by the following general formula (6), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 14] [In the formula, Z ₅ is And n represents 2 or 3. At least two of R _{a to} R _c are And a plurality of the substituents may be the same or different. Of R _{a to} R _c , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent. Further, Ar represents a divalent arylene group, and R _{1 to} R ₈ each represent a hydrogen atom or a substituent. Among R _{1 to} R ₈ , adjacent substituents may be condensed with each other to form a ring. ] 7. The compound represented by the general formula (1) is
It is a compound represented by the following general formula (7), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 17] [In the formula, Z ₆ is And n represents 2 or 3. At least two of R _{a to} R _d are And a plurality of the substituents may be the same or different. Of R _{a to} R _d , those which are not the above substituents each represent a hydrogen atom or an arbitrary substituent, and adjacent substituents may be condensed with each other to form a ring. Ar represents a divalent arylene group, R _{1 to} R ₈
Each represents a hydrogen atom or a substituent. Of R _{1 to} R ₈ ,
Adjacent substituents may be condensed with each other to form a ring. ] 8. The compound represented by the general formula (1):
It is a compound represented by the following general formula (8), The organic electroluminescent element of Claim 1 characterized by the above-mentioned. [Chemical 20] [In the formula, Ar ₁ represents an m-valent arylene group, and R _{1 to} R ₈
Each represents a hydrogen atom or a substituent. n represents an integer of 2 or more and 6 or less. Among R _{1 to} R ₈ , adjacent substituents may be condensed with each other to form a ring. ] 9. The electron transport layer comprises the compound represented by the general formula (1) to
An organic electroluminescence device comprising at least one compound selected from the compounds represented by (8). 10. The light-emitting layer has the general formulas (1) to (8).
An organic electroluminescence device comprising at least one compound selected from compounds represented by: 11. An organic electroluminescent device having a light emitting layer containing a host compound and a phosphorescent compound, wherein the host compound is one of the compounds represented by the general formulas (1) to (1).
An organic electroluminescence device comprising at least one compound selected from the compounds represented by (8). 12. The organic electroluminescence device according to claim 11, wherein the phosphorescent compound is an iridium compound, an osmium compound or a platinum compound. 13. The organic electroluminescence device according to claim 11, wherein the phosphorescent compound is an iridium compound. 14. A display device comprising the organic electroluminescence element according to claim 1. Description: