JP2000226573A - Organic luminescent material and organic electroluminescent device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an organic luminescent material affording high emission luminance and new luminescent color, and to obtain an organic electroluminescent device using the above material. SOLUTION: This organic luminescent material is an organic polynuclear metal complex compound having a plurality of central metal atoms and ligands coordinated on the central metal atoms; wherein the ligand to be used is an organic polynuclear metal complex compound containing a <=5C nitrogen-contg. aromatic ring with the nitrogen atom as coordinated atom, an organoboron complex compound with the nitrogen atom in the nitrogen-contg. aromatic ring bound to the boron atom, or an organoboron complex compound with an electron-accepting phenyl group as ligand.

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 material used for an organic electroluminescence device, and an organic electroluminescence device using the same.

[0002]

2. Description of the Related Art A display panel provided with an electroluminescent element has high visibility and excellent display capability.
It has the feature that high-speed response is also possible.

In recent years, reports have been made on organic electroluminescent devices using an organic compound as a light-emitting material (for example, Applied Physics Letters, Vol. 51, p. 913, 1987 (Applied Physics).
ics Letters, 51, 1987, p. 91
3. )). In this report, C.I. W. Tang et al. Disclose an organic electroluminescent device having a structure in which an organic light emitting layer and a charge transport layer are stacked. In this report, a tris (8-quinolinol) aluminum complex (hereinafter referred to as Alq) having both high luminous efficiency and electron transport ability as a luminescent material is described.
To obtain an excellent organic electroluminescent device. Also, Journal of Applied Physics, Vol. 65, p. 3610, 1989 (J
ownnal Applied Physics,
65, 1989, p. No. 3610) discloses that Alq forming an organic light emitting layer has a coumarin derivative or DCM1 (Eastm).
It has been reported that an element doped with a fluorescent dye such as an anionic (Chemicals) is manufactured, and the emission color is changed by selecting the dye, and that the luminous efficiency is increased as compared with undoped.

At present, much research and development has been carried out following the above-mentioned research, and chelate metal complexes having a fluorescent property, electron transporting organic molecules and hole transporting organic molecules have been developed and studied as new device materials.

[0005]

However, in the organic electroluminescence device, in order to increase the luminous efficiency or to obtain a new luminescent color for color display,
Further, there is a problem that a new organic light emitting material is required.

[0006] In order to solve the above-mentioned conventional problems, it is a first object of the present invention to provide an organic light emitting material which gives a high light emission luminance and a new light emission color.

It is a second object of the present invention to provide an organic electroluminescent device that provides high emission luminance and a new emission color.

[0008]

In order to achieve the first object, a first organic light-emitting material of the present invention is an organic light-emitting material comprising an organic polynuclear metal complex compound, wherein the organic polynuclear metal complex is an organic light-emitting material. The compound has a plurality of central metals and a ligand coordinated to the central metal, wherein the ligand includes a nitrogen-containing aromatic ring having 5 or less carbon atoms, and the nitrogen of the nitrogen-containing aromatic ring is a coordinating atom. It is characterized by the following. In the first organic light emitting material,
Since a plurality of central atoms of the organic polynuclear metal complex compound and a nitrogen atom as a coordination atom form a strong bond, the compound is stable even at a high temperature such as during vapor deposition. Therefore, according to the first organic light-emitting material, an organic light-emitting material giving high light emission luminance can be obtained. In the first organic light-emitting material, an organic light-emitting material that gives a new luminescent color can be obtained by changing the ligand.

In the first organic light-emitting material, the nitrogen-containing aromatic ring contains at least two nitrogen atoms, and the two nitrogen atoms are bonded to the plurality of central metals, whereby the plurality of central metals and the plurality of central metals are linked to each other. It is preferred that the ligand forms a metal-containing cyclic bond structure. According to the above configuration,
Since the organic polynuclear metal complex compound has a stable metal-containing cyclic bond structure formed by a bridge ligand having a nitrogen-containing aromatic ring and a central metal, the compound is particularly stable even at a high temperature such as during vapor deposition. Therefore, according to the above configuration, it is possible to obtain an organic light emitting material that gives a particularly high luminance.

The second organic light emitting material of the present invention is an organic light emitting material comprising an organic boron complex compound, wherein the organic boron complex compound contains a nitrogen-containing aromatic ring having 5 or less carbon atoms, Is bonded to boron. In the second organic light emitting material, since the bond between nitrogen and boron is strong, the material is stable even at a high temperature such as during vapor deposition. Therefore, according to the second organic light emitting material, an organic light emitting material that provides high light emission luminance can be obtained. In the second organic light-emitting material, an organic light-emitting material that gives a new light-emitting color can be obtained by changing the type of the ligand-containing nitrogen-containing aromatic ring.

In the first and second organic light emitting materials,
The nitrogen-containing aromatic ring preferably has a cyclic structure equivalent to the cyclic structure of at least one selected from pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole and oxadiazole. . These aromatic rings have strong aromaticity and conjugated electrons are delocalized, and form a strong bond with the central metal, so that a stable metal complex compound can be formed.

In the first organic light-emitting material, it is preferable that the central metal of the organic polynuclear metal complex compound is boron (boron has a semimetallic property and may be classified as a nonmetal. However, they are treated here as metals classified into Group III). The organic boron complex compound has a strong bond between the small atomic radius boron and the organic ligand and is extremely stable thermally, so it exists particularly stably even at high temperatures such as during vapor deposition, and is an excellent fluorescent light-emitting thin film. Can be formed.

In the first organic light emitting material, it is preferable that the organic polynuclear metal complex compound has a pyrazaball structure. By using an organic polynuclear metal complex compound having a pyrazaball structure, an excellent organic light emitting material which is chemically stable and has high fluorescence luminance can be obtained. Further, an organic boron complex compound having a pyrazaball structure is preferable as an organic light emitting material that emits light in a blue wavelength range.

In the first organic light-emitting material, the organic polynuclear metal complex compound is preferably 4,4,8,8-tetrakis (1H-pyrazol-1-yl) pyrazaball. 4,4,8,8-tetrakis (1H-pyrazole-
1-yl) pyraza ball has six pyrazole rings coordinated to boron, and is preferable as an organic light emitting material. 4,
4,8,8-Tetrakis (1H-pyrazol-1-yl) pyraza ball is an organic light-emitting material that emits blue-violet light and is a host of light-emitting materials that have a light emission peak in the visible light emission wavelength range from purple to red. It is very effective as a component and is preferable as an organic light emitting material showing high luminous efficiency. 4,4,8,8-tetrakis (1H-pyrazole-
1-yl) pyraza balls can be used as an excellent light-emitting material in place of Alq, which is essential for an organic light-emitting device.

The third organic luminescent material of the present invention is characterized by comprising an organic boron complex compound having an electron-accepting phenyl group as a ligand. This organic boron complex compound forms a metal complex compound that has a strong bond between boron having a small atomic radius and an electron-accepting phenyl group and is extremely stable thermally, and exists stably even at a high temperature such as during vapor deposition. Therefore,
According to the third organic light-emitting material, an organic light-emitting material giving high light emission luminance can be obtained. In the third organic light-emitting material, an organic light-emitting material that gives a new luminescent color can be obtained by changing the ligand.

In order to achieve the second object, an organic electroluminescence device according to the present invention comprises a hole injecting electrode, an electron injecting electrode, and an electrode between the hole injecting electrode and the electron injecting electrode. And a light-emitting layer disposed in the organic electroluminescence device, wherein the light-emitting layer contains any of the first to third organic light-emitting materials. Since the organic electroluminescent element contains the organic light emitting material of the present invention, an organic electroluminescent element that provides high emission luminance and a novel emission color can be obtained.

In the organic electroluminescence device, the light emitting layer preferably further contains at least one compound selected from a compound having a nitrogen-containing aromatic ring having 5 or less carbon atoms and a polycyclic aromatic hydrocarbon derivative. When the light-emitting layer contains these compounds, these compounds act as a guest of the organic polynuclear metal complex compound serving as a host, so that light emission is increased in luminance and various luminescent colors are obtained.

In the above organic electroluminescence device, the light emitting layer preferably further contains a compound having one cyclic structure selected from an anthracene ring and a phenanthrene ring. When the light emitting layer further contains the above compound, the peak wavelength of light emission can be changed. In particular, when the light-emitting layer contains an organic boron complex compound, an organic electroluminescence device having high luminous efficiency near a blue wavelength (440 to 475 nm) can be obtained.

In the above organic electroluminescent device, the light emitting layer preferably contains an organic polynuclear metal complex compound having a pyrazaball structure and at least one selected from diphenylanthracene and a diphenylanthracene derivative. When the light-emitting layer contains diphenylanthracene or a diphenylanthracene derivative, an organic electroluminescent device having high luminous efficiency near a blue wavelength (430 to 475 nm) can be obtained.

In the above-mentioned organic electroluminescence device, the light-emitting layer is composed of pyrrole, imidazole, pyrazole,
It is preferable to further include a compound having a cyclic structure equal to the cyclic structure of at least one selected from triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole and oxadiazole. These compounds have aromaticity and delocalized conjugated electrons, and emit fluorescent light of various colors.
Therefore, by including the compound in the light-emitting layer,
Organic electroluminescent devices having various emission colors can be obtained.

In the organic electroluminescence device, the compound contained in the light emitting layer preferably has a photoluminescence peak of 580 nm or more and 680 nm or less. Photoluminescence peak is 580n
By containing a compound having a size of m or more and 680 nm or less, an organic electroluminescence device having a red emission color can be obtained.

[0022]

An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 In Embodiment 1, an organic light emitting material comprising an organic polynuclear metal complex compound having a ligand having nitrogen as a coordinating atom in a nitrogen-containing aromatic ring will be described.

The organic light-emitting material of Embodiment 1 is an organic light-emitting material comprising an organic polynuclear metal complex compound, wherein the organic polynuclear metal complex compound comprises a plurality of central metals and a ligand coordinated to the central metal. And the ligand includes a nitrogen-containing aromatic ring having 5 or less carbon atoms, and the nitrogen of the nitrogen-containing aromatic ring is used as a coordination atom.

In the organic light-emitting material, examples of the nitrogen-containing aromatic ring having 5 or less carbon atoms include pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole and oxadiazole. A nitrogen-containing aromatic ring having the same cyclic structure as the cyclic structure having the same. The hetero-condensed polycyclic ring in which an aromatic ring is condensed with a nitrogen-containing aromatic ring having 5 or less carbon atoms, such as carbazole and benzimidazole, is also included in the nitrogen-containing aromatic ring having 5 or less carbon atoms of the present invention. Has the same action as a ring.
These nitrogen-containing aromatic rings have strong aromaticity and delocalized conjugated electrons, act as ligands to form strong covalent metal chelate bonds, and form stable metal complex compounds . Further, the metal complex compound having a nitrogen-containing aromatic ring as a ligand as described above often forms a complex conformational structure, and often takes various molecular aggregation forms as a molecular aggregation structure.

In the above organic light emitting material, the metal element used as the central metal of the organic polynuclear metal complex compound includes:
One metal element selected from Be, Mg, Ca, B, Al and Ga is desirable.

Among the above organic polynuclear metal complex compounds, an organic boron complex compound in which the central metal is boron has a strong bond between boron having a small atomic radius and an organic ligand, and is a metal complex which is extremely thermally stable. Since the compound is formed and exists particularly stably even at a high temperature such as during vapor deposition, it is particularly preferable as a light emitting material.

In the above organic light emitting material, the nitrogen-containing aromatic ring of the ligand contains at least two nitrogen atoms,
It is preferable that the central metal and the ligand form a cyclic structure by coordinating one nitrogen atom to a plurality of central metals.

In the above-mentioned organic polynuclear metal complex compound of the organic light emitting material, an example in which the central metal is boron and two borons are cross-linked by a cross-linking ligand,
Formula (1) shows the structural formula.

[0030]

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(Where R ₁ and R ₂ in the formula are bridging ligands having a nitrogen-containing aromatic ring containing at least two nitrogen atoms, and the nitrogen atom in the nitrogen-containing aromatic ring is used as a coordinating atom. In the formula, R ₃ , R ₄ , R ₅ and R ₆ are each pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole, oxadiazole and derivatives thereof. Wherein the nitrogen atom in the nitrogen-containing aromatic ring is a ligand.) In the organic polynuclear metal complex compound of the formula (1), boron is cross-linked by the cross-linking ligands R ₁ and R ₂ . To form an annular structure. Note that R _{3 to} R ₆ in the formula (1) are examples,
Other ligands may be used (similar in formula 2).

As an example of the organic boron complex compound of the formula (1), the structural formula of an organic boron complex compound having a pyrazaball structure in which the bridging ligands R ₁ and R ₂ are pyrazole is shown in the formula (2).

[0033]

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(In the formula, R ₃ , R ₄ , R ₅ and R ₆ are the same as those in the formula 1.) The dashed line A in the formula (2) indicates a pyraza ball structure. The pyrazaball structure is a very stable structure in which two pyrazoles cross-link two borons as a cross-linking ligand to form a cyclic structure. The present invention also includes an organic light emitting material comprising an organic boron complex compound having a halopyrazaball structure using halopyrazole obtained by substituting halogen such as fluorine or chlorine for pyrazole having a pyrazaball structure as a ligand.

An example of an organoboron complex compound having a pyrazaball structure is represented by the following formula (3):
4,8,8-tetrakis (1H-pyrazol-1-yl) pyrazaball (hereinafter referred to as PPZB).

[0036]

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According to the organic light-emitting material described in the first embodiment, an organic light-emitting material that gives high light emission luminance and a new light emission color can be obtained.

Embodiment 2 In Embodiment 2, another example of the organic light emitting material of the present invention will be described.

The organic light emitting material of Embodiment 2 is made of an organic boron complex compound having an electron-accepting phenyl group as a ligand.

As an organic boron complex compound having an electron-accepting phenyl group as a ligand, there is, for example, one represented by the structural formula (4).

[0041]

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(Wherein R _{7 to} R ₉ each independently represent an electron-accepting phenyl group.) Examples of the electron-accepting phenyl group include halogen, cyano, nitro and carbonyl, which are electron-accepting groups. And a phenyl group substituted with a group. In these, an electron-accepting aromatic ring serves as a ligand to form a stable organic boron complex compound, thereby forming an excellent fluorescent light emitting thin film.

Examples of the organic boron complex compound having a phenyl group substituted with halogen as a ligand include an organic boron complex salt having a tetrakis (halophenyl) borate structure. As an example of the organic boron complex salt having a tetrakis (halophenyl) borate structure, potassium tetrakis (4-chlorophenyl) borate represented by the following formula (5) is given.

[0044]

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As the halogen element used for the tetrakis (halophenyl) borate, fluorine is the most electron-accepting and chemically stable, and examples thereof include magnesium tetrakis (4-fluorophenyl) borate.

According to the organic light-emitting material described in the second embodiment, an organic light-emitting material that provides high light emission luminance and a new light emission color can be obtained.

Embodiment 3 In Embodiment 3, an example of the organic electroluminescent device of the present invention will be described.

Referring to FIG. 1, an organic electroluminescence device 10 of the present invention comprises a transparent substrate 11, a hole injection electrode 12, a hole transport layer 13, and a light emitting layer 14 sequentially laminated on the transparent substrate 11. , An electron transport layer 15, and an electron injection electrode 16. Although FIG. 1 shows the light emitting device 10 including the electron transport layer, the light emitting layer 14 may be an organic electroluminescent device 10a (see FIG. 2) which also serves as the electron transport layer. Further, the organic electroluminescence device of the present invention may include a conductive polymer layer, a charge injection layer, and the like.

For the transparent substrate 11, for example, glass can be used.

The hole injection electrode 12 is an electrode for injecting holes, and is made of a conductive material having a high work function.
When light is extracted from the hole injection electrode 12 side, a translucent material is used for the hole injection electrode 12, and for example, ITO (Indium Tin Oxide) is used.

The hole transporting layer 13 is a layer for transporting holes to the light emitting layer 14. The hole transport layer 13 includes, for example, N, N′-bis (3-methylpheny).
l) -N, N'-diphenyl- (1,1'-bi
phenyl) -4,4'-diamine (hereinafter T
An aromatic polyamine represented by PD) or a heterocyclic fused polycyclic compound containing a nitrogen element or a sulfur element can be used.

The light emitting layer 14 is a layer that emits light by the injected electrons and holes. In the organic electroluminescence device 10a shown in FIG. 2, the light emitting layer 14 also functions as an electron transport layer.

The light emitting layer 14 contains the organic light emitting material described in the first or second embodiment. In the organic electroluminescence device 10 shown in FIG. 1, the thickness of the light emitting layer 14 is, for example, 30 nm to 80 nm. Further, in the organic electroluminescence device 10a shown in FIG.
The thickness of the light emitting layer 14 is, for example, 5 nm to 25 nm. In the organic electroluminescence device 10a, when an organic boron complex compound is used for the light emitting layer 14 and a metal electrode is used for the electron injection electrode 16, the interface between the light emitting layer 14 and the electron injection electrode 16 is stabilized. As a result, a highly reliable organic electroluminescent device can be obtained.

The light emitting layer 14 preferably contains at least one compound selected from a compound having a nitrogen-containing aromatic ring having 5 or less carbon atoms and a polycyclic aromatic hydrocarbon derivative. By doping these compounds into the light-emitting layer 14, organic light-emitting devices having various emission colors can be obtained.

As the polycyclic aromatic hydrocarbon derivative doped into the light emitting layer 14, a polycyclic aromatic hydrocarbon derivative having one cyclic structure selected from an anthracene ring and a phenanthrene ring can be used.

Specific examples of the polycyclic aromatic hydrocarbon derivative doped into the light emitting layer 14 include rubrene, decacyclene, diphenylanthracene, dibenzoanthracene, pentacene, dibenzopentacene, bisphenylethynylanthracene, bisphenylethynylnaphthacene. And derivatives of pentaphenylcyclopentadiene and tetraphenylcyclopentadiene, and alkyl-substituted, alkoxy-substituted, and halogen-substituted products thereof.

When an organic boron complex compound having a pyraza-ball structure is used for the light emitting layer 14, an organic electroluminescent device having a particularly high luminance can be obtained by doping diphenylanthracene or a derivative thereof as a polycyclic aromatic hydrocarbon derivative. can get. As a combination of these, for example, a combination in which a light emitting layer made of PPZB is doped with 9,10-bis (4-methoxyphenyl) anthracene is preferable.

Compounds having a nitrogen-containing aromatic ring having 5 or less carbon atoms which are doped into the light emitting layer 14 include, for example, pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole and oxazole. A compound having a cyclic structure equal to the cyclic structure of one selected from diazoles is exemplified. By doping the fluorescent layer 34 with a nitrogen-containing aromatic ring-containing compound having a photoluminescence peak wavelength of 580 nm or more and 680 nm or less, an organic electroluminescence device that emits red light can be obtained.

The electron transport layer 15 is a layer for transporting electrons to the light emitting layer 14. As the electron transport layer 15, for example, Alq can be used.

The electron injection electrode 16 is an electrode for injecting electrons. For the electron injection electrode 16, a conductive material having a low work function is used. For example, a metal thin film containing an alkali metal or an alkaline earth metal is used as the electron injection electrode 16. When light is extracted from the hole injection electrode 12 side, it is preferable to use a metal thin film having a high reflectance for the electron injection electrode 16. Electrode for electron injection 16
For example, an Mg-Ag alloy, a Ca-Ag alloy, an Al-based alloy, or the like can be used. As the Al-based alloy, Al-Li alloy, Li-Al-Zn alloy,
A Ca-Al alloy, a Mg-Al alloy, a Sn-Al-Li alloy, a Bi-Al-Li alloy, an In-Al-Li alloy, or the like can be used.

In the organic electroluminescent elements 10 and 30a of the third embodiment, the hole injection electrode 12
By applying a forward voltage to the electron injection electrode 16, the light emitting layer 14 can emit light.

Next, an example of a method for manufacturing the organic electroluminescence device 10 will be described with reference to FIG. First, the hole injection electrode 12 is formed on the transparent substrate 11 by, for example, a sputtering method. afterwards,
On the hole injection electrode 12, the hole transport layer 13, the light emitting layer 14,
The electron transport layer 15 is sequentially formed by, for example, an evaporation method. Then, the organic electroluminescent element 10 can be manufactured by forming the electron injection electrode 16 by, for example, a sputtering method or an evaporation method.

In the organic electroluminescent elements 10 and 30a of the third embodiment, the light emitting layer 14 contains the light emitting material of the present invention described in the first or second embodiment. Therefore, according to the organic electroluminescent elements 10 and 30a, an organic electroluminescent element that provides high emission luminance and a new emission color can be obtained. Furthermore, since the luminescent material of the present invention is stable even at high temperatures, a highly reliable organic electroluminescent device can be obtained.

[0064]

Embodiments of the present invention will be described below.

Example 1 In Example 1, an example in which the organic electroluminescence device 10 shown in FIG. 1 was manufactured will be described.

In Example 1, the transparent substrate 11 was a glass substrate (1 mm thick), the hole injection electrode 12 was ITO, the hole transport layer 13 was TPD (80 nm thick), and the light emitting layer 14 was PP.
ZB (film thickness: 20 nm, manufactured by Aldrich, product number 3
9418-1), the electron transport layer 15 is made of Alq (film thickness 50n).
m), an aluminum thin film (thickness: 180 nm) containing 1.7% by weight of lithium was used as an electron injection electrode.

ITO was formed by a sputtering method, and TPD, PPZB and Alq were formed by a vapor deposition method at a vapor deposition rate of 0.1 nm / sec. The lithium-containing aluminum thin film was formed by a vapor deposition method. Thus, a double hetero organic electroluminescent device was formed.

When a direct current voltage was applied to the organic electroluminescent element and the emission characteristics thereof were measured, the organic electroluminescence element showed a violet (425 nm) emission and 8 mA when 6 V was applied.
/ Cm ² , and a luminance of ²⁰ cd / m ² was obtained.

(Embodiment 2) In Embodiment 2, an example in which the organic electroluminescence element 10a shown in FIG. 2 is manufactured will be described.

The second embodiment is the same as the first embodiment except that the electron transport layer 15 is not provided and the light emitting layer 14 is different from the first embodiment.

The light-emitting layer 14 of the organic electroluminescence device of Example 2 was prepared by adding 9,10-bis (4-
(Methoxyphenyl) anthracene doped with 20 wt% (film thickness: 50 nm), and formed by an evaporation method.

A direct current voltage was applied to the organic electroluminescent device of Example 2 to measure its light emission characteristics. The result was blue (peak wavelength: 455 nm, half width: 94 nm).
And a current of 9 mA / cm ² flowed by application of 8 V, and a luminance of 350 cd / m ² was obtained.

Thin film samples of PPZB and 9,10
When the photoluminescence of a thin film sample of -bis (4-methoxyphenyl) anthracene was measured, PP
ZB showed a photoluminescence peak at 400 nm, and 9,10-bis (4-methoxyphenyl) anthracene showed a photoluminescence peak at 455 nm. Therefore, when Examples 1 and 2 are compared, organic electroluminescence is obtained by doping 9,10-bis (4-methoxyphenyl) anthracene having a photoluminescence peak on the longer wavelength side than PPZB into PPZB. It was found that the emission peak of the device could be shifted to the longer wavelength side.

Embodiment 3 In Embodiment 3, another example of the organic electroluminescence device 10a shown in FIG. 2 will be described. The organic electroluminescent element of the third embodiment differs from the organic electroluminescent element of the second embodiment only in the light emitting layer 14, and a duplicate description will be omitted.

The light emitting layer 14 of the organic electroluminescence device of Example 3 was made of 4,4,8,8-tetrakis (1
H-pyridazin-1-yl) pyrazaball (film thickness 50 n)
m) and was formed by an evaporation method.

A direct current voltage was applied to the organic electroluminescence device of Example 3 to measure its light emission characteristics. The result was blue (peak wavelength: 465 nm, half width: 104 nm).
m), and a current of 12 mA / cm ² flowed when 8 V was applied, and a luminance of 230 cd / m ² was obtained.

Fourth Embodiment In a fourth embodiment, another example of the organic electroluminescence element 10a shown in FIG. 2 will be described. The organic electroluminescent element of the fourth embodiment differs from the organic electroluminescent element of the second embodiment only in the light-emitting layer 14, and a duplicate description will be omitted.

The light emitting layer 14 of the organic electroluminescence device of Example 4 was made of 4,4,8,8-tetrakis (1
(H-benzimidazol-1-yl) pyraza ball (film thickness 50 nm) and formed by an evaporation method.

When a direct current voltage was applied to the organic electroluminescent device of Example 4 to measure the light emission characteristics thereof, blue (peak wavelength: 470 nm, half width: 110 nm) was obtained.
m), and a current of 16 mA / cm ² flowed when 8 V was applied, and a luminance of 260 cd / m ² was obtained.

Embodiment 5 In Embodiment 5, another example of the organic electroluminescence element 10a shown in FIG. 2 will be described. The organic electroluminescent element of Example 5 is different from the organic electroluminescent element of Example 2 only in the hole transport layer 13 and the light emitting layer 14, and therefore, the duplicated description will be omitted.

The hole transport layer 13 of the organic electroluminescence device of Example 5 was made of rubrene (5, 6, 11, 1).
TP doped with 3% 2-tetraphenylnaphthacene)
D (thickness: 70 nm) and formed by an evaporation method.

The light emitting layer of the organic electroluminescence device of Example 5 was made of PPZB (film thickness: 50 nm) doped with pentaphenylcyclopentadiene by 15 wt%, and was formed by a vapor deposition method.

A direct current voltage was applied to the organic electroluminescence device of Example 5 to measure its light emission characteristics. The result was blue (peak wavelength: 465 nm, half width: 110 nm).
m), and a current of 5 mA / cm ² flowed by application of 8 V, and a luminance of 65 cd / m ² was obtained.

(Embodiment 6) In Embodiment 6, another example of the organic electroluminescence element 10a shown in FIG. 2 will be described. The organic electroluminescent element of the sixth embodiment differs from the organic electroluminescent element of the second embodiment only in the light emitting layer 14, and a duplicate description will be omitted.

The light emitting layer of the organic electroluminescence device of Example 6 was made of PPZB (50 nm thick) doped with 4 wt% of dibenzopentacene, and was formed by an evaporation method.

A direct current voltage was applied to the organic electroluminescence device of Example 6 to measure its light emission characteristics. The result was red (peak wavelength: 600 nm, half width: 120 nm).
m), and a current of 17 mA / cm ² flowed when 8 V was applied, and a luminance of 170 cd / m ² was obtained.

(Embodiment 7) In Embodiment 7, another example of the organic electroluminescence element 10a shown in FIG. 2 will be described. The organic electroluminescent element of the seventh embodiment differs from the organic electroluminescent element of the second embodiment only in the light emitting layer 14, and a duplicate description will be omitted.

The light emitting layer of the organic electroluminescence device of Example 7 was composed of 2,4-bis (5,6-diphenyl-
1,2,4-triazin-3-yl) pyridine was added for 30w.
It is made of PPZB (thickness: 50 nm) doped with t% and formed by an evaporation method.

When a direct current voltage was applied to the organic electroluminescent device of Example 7 to measure the light emission characteristics, the organic electroluminescent device was found to be clear (peak wavelength: 590 nm, half width: 105 nm).
m), and a current of 12 mA / cm ² flowed when 8 V was applied, and a luminance of 240 cd / m ² was obtained.

Although the embodiments of the present invention have been described with reference to the examples, the present invention is not limited to the above embodiments, but can be applied to other embodiments based on the technical idea of the present invention. .

[0091]

As described above, according to the organic light-emitting material of the present invention, an organic light-emitting material that provides high light emission luminance and a new light emission color can be obtained.

Further, the organic electroluminescence device of the present invention contains the organic light emitting material of the present invention. Therefore, according to the organic electroluminescence device of the present invention, an organic electroluminescence device that provides high emission luminance and a new emission color can be obtained. Further, in the organic electroluminescence device of the present invention, the emission luminance and the emission color can be changed by changing the compound to be doped.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one example of an organic electroluminescence device of the present invention.

FIG. 2 is a cross-sectional view illustrating another example of the organic electroluminescence element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10, 10a Organic electroluminescent element 11 Transparent substrate 12 Electrode for hole injection 13 Hole transport layer 14 Light emitting layer 15 Electron transport layer 16 Electrode for electron injection

Claims (13)

[Claims] 1. An organic light-emitting material comprising an organic polynuclear metal complex compound, wherein the organic polynuclear metal complex compound has a plurality of central metals and a ligand coordinated to the central metal. Is an organic light-emitting material comprising a nitrogen-containing aromatic ring having 5 or less carbon atoms, wherein nitrogen of the nitrogen-containing aromatic ring is used as a coordinating atom. 2. The nitrogen-containing aromatic ring contains at least two nitrogen atoms, and the two nitrogen atoms are bonded to the plurality of central metals so that the plurality of central metals and the ligand form a metal-containing ring. The organic light emitting material according to claim 1, which forms a bonding structure. 3. An organic light emitting material comprising an organic boron complex compound, wherein the organic boron complex compound contains a nitrogen-containing aromatic ring having 5 or less carbon atoms, and nitrogen of the nitrogen-containing aromatic ring is bonded to boron. An organic light-emitting material, characterized in that: 4. A cyclic structure in which the nitrogen-containing aromatic ring is equivalent to a cyclic structure of at least one selected from pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine, oxazole and oxadiazole. The organic light-emitting material according to claim 2, comprising: 5. The organic light emitting material according to claim 2, wherein the organic polynuclear metal complex compound has a pyrazaball structure. 6. The method according to claim 1, wherein the organic polynuclear metal complex compound is 4,4,4.
The organic light-emitting material according to claim 5, which is 8,8-tetrakis (1H-pyrazol-1-yl) pyrazaball. 7. An organic light-emitting material comprising an organic boron complex compound having an electron-accepting phenyl group as a ligand. 8. An electrode for hole injection, an electrode for electron injection,
An organic electroluminescence device comprising: a hole-injection electrode and a light-emitting layer disposed between the electron-injection electrode, wherein the light-emitting layer comprises the organic light-emitting material according to claim 4. An organic electroluminescent device, comprising: 9. The organic electroluminescent device according to claim 8, wherein the light emitting layer further includes at least one compound selected from a compound containing a nitrogen-containing aromatic ring having 5 or less carbon atoms and a polycyclic aromatic hydrocarbon derivative. . 10. The organic electroluminescence device according to claim 8, wherein the light emitting layer further includes a compound having one cyclic structure selected from an anthracene ring and a phenanthrene ring. 11. The organic electroluminescent device according to claim 8, wherein the light emitting layer includes the organic polynuclear metal complex compound according to claim 5, and at least one selected from diphenylanthracene and a diphenylanthracene derivative. 12. The light-emitting layer according to claim 1, wherein the light-emitting layer comprises pyrrole, imidazole, pyrazole, triazole, pyridine, pyridazine, pyrazine, pyrimidine, triazine, tetrazine,
The organic electroluminescent device according to claim 8, further comprising a compound having a cyclic structure equal to a cyclic structure of at least one selected from oxazole and oxadiazole. 13. The compound according to claim 1, wherein a peak of photoluminescence is 580 nm or more and 680 nm or less.
3. The organic electroluminescent device according to 2.