JP2006265144A - Metal complex compound and organic electroluminescent element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element having high luminous efficiency with long life and provide a metal complex compound that can realize these merits. <P>SOLUTION: In a metal complex compound having a specific structure and an organic electroluminescent device that has at least a monolayer or multiple layers of organic thin film layers between the cathode and the anode, at least one layer in the organic thin film layers is the organic electroluminescent device including the metal complex compounds as a single or multiple components. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel metal complex compound and an organic electroluminescence device using the same, and more particularly, to a long-life organic electroluminescence device having high emission luminance and high emission efficiency and a novel metal complex compound that realizes the same. is there.

  In an organic electroluminescence element (hereinafter, electroluminescence may be abbreviated as EL), a fluorescent substance emits light by recombination energy of holes injected from an anode and electrons injected from a cathode by applying an electric field. It is a self-luminous element utilizing the principle of Eastman Kodak's C.I. W. Tang et al. Reported on a low-voltage driven organic EL element using a stacked element (CW Tang, SA Vanslyke, Applied Physics Letters, 51, 913, 1987, etc.). Since then, researches on organic EL elements using organic materials as constituent materials have been actively conducted. Tang et al. Use tris (8-quinolinolato) aluminum for the light emitting layer and a triphenyldiamine derivative for the hole transporting layer. The advantages of the stacked structure are that it increases the efficiency of hole injection into the light-emitting layer, blocks the electrons injected from the cathode, increases the generation efficiency of excitons generated by recombination, and generates in the light-emitting layer For example, confining excitons. As in this example, the organic EL device has an element structure of a hole transport (injection) layer, an electron transporting light emitting layer, or a hole transport (injection) layer, a light emitting layer, an electron transport (injection) layer. The three-layer type is well known. In such a stacked structure element, the element structure and the formation method are devised in order to increase the recombination efficiency of injected holes and electrons.

As light emitting materials, metal complex compounds such as tris (8-quinolinolato) aluminum complex, light emitting materials such as coumarin derivatives, tetraphenylbutadiene derivatives, bisstyrylarylene derivatives, oxadiazole derivatives and the like are known. It is reported that light emission in the visible region from red to red is obtained, and realization of a color display element is expected (for example, Patent Document 1, Patent Document 2, Patent Document 3 and the like).
In recent years, it has been proposed to use a phosphorescent material, which is a metal complex compound, in addition to a fluorescent material in the light emitting layer of an organic EL element (Non-patent Document 1). In this way, high emission efficiency is achieved by utilizing the singlet and triplet excited states of the phosphorescent material in the light emitting layer of the organic EL element. When electrons and holes are recombined in an organic EL device, it is considered that singlet excitons and triplet excitons are generated at a ratio of 1: 3 due to the difference in spin multiplicity. If the light emitting material is used, it can be considered that the light emission efficiency is 3 to 4 times that of an element using only fluorescence. In such an organic EL device, an anode, a hole transport layer, an organic light emitting layer, an electron transport layer (hole blocking layer), and an electron transport are sequentially arranged so that the triplet excited state or triplet exciton is not quenched. A structure in which layers are stacked such as a layer and a cathode has been used, and a host compound and a phosphorescent compound have been used in an organic light emitting layer (Patent Documents 4 and 5).

  In addition, examples of metal complex compounds in which aluminum, beryllium, zinc, magnesium, or the like is used as a central metal have been reported (for example, Patent Document 6, Patent Document 7, and Patent Document 8). These are used not only as light emitting materials but also as carrier transport materials, particularly as electron transport materials (Non-patent Document 2). However, these are excellent in electron transport properties, but their life and luminous efficiency are not sufficient, and further improvement is required.

JP-A-8-239655 Japanese Patent Laid-Open No. 7-183561 JP-A-3-200289 US Pat. No. 6,097,147 International Publication No. WO01 / 41512 Japanese Patent Laid-Open No. 10-308279 JP-A-11-149983 JP 2000-357588 A M.M. A. Baldo, et al. , Appl. Phys. Lett. , 75, 4 (1999) Supervised by Junji Kido, “Organic EL materials and displays”, CMC (2001)

  An object of the present invention is to provide an organic EL element having high luminous efficiency and a long lifetime, and a material for an organic EL element that realizes the organic EL element.

  As a result of intensive studies in order to solve the above problems, the present inventors have used a metal complex compound represented by the following general formula (I) or (II) as a material for an organic EL device, thereby improving luminous efficiency. It has been found that an organic EL device having a high lifetime and a long lifetime can be produced. The present invention has been completed based on such findings.

  That is, the present invention provides an organic electroluminescence device in which a single organic layer or a plurality of organic thin film layers including at least a light emitting layer is sandwiched between a cathode and an anode. ) Or (II) An organic electroluminescent device containing a metal complex compound having a specific structure represented by (II) alone or as a component of a mixture is provided.

Moreover, this invention provides the ligand compound represented by the following general formula (III) which is a ligand of the metal complex compound of the said general formula (I) or (II).

  The organic EL device using the metal complex compound of the present invention for the organic thin film layer has high luminous efficiency, high luminance and long life, particularly when the metal complex compound of the present invention is used as a light emitting material.

  In the organic electroluminescence device in which one or more organic thin film layers including at least a light emitting layer are sandwiched between a cathode and an anode, at least one of the organic thin film layers has the general formula (I) or ( An organic electroluminescence device containing a metal complex compound having a specific structure represented by II) alone or as a component of a mixture is provided.

In the formula, R ^{1 to} R ¹² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 nuclear carbon atoms, a substituted or unsubstituted aryl group having 5 to 50 nuclear carbon atoms, substituted or unsubstituted. An aralkyl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 50 nuclear carbon atoms, a substituted or unsubstituted alkoxyl group having 1 to 50 nuclear carbon atoms, a substituted or unsubstituted nuclear carbon number 5-50 aryloxy group, substituted or unsubstituted arylamino group having 5-50 carbon atoms, substituted or unsubstituted alkylamino group having 1-20 carbon atoms, substituted or unsubstituted 4-4 carbon atoms 50 heterocyclic groups, cyano groups, or halogen atoms.
Adjacent ones of R ^{1 to} R ⁴ , R ^{5 to} R ⁸ , and R ^{9 to} R ¹² may be bonded to each other to form a substituted or unsubstituted cyclic structure.
In the general formula (I), m is an integer of 1 to 3, and n is an integer of 0 to 2. In general formula (II), m is 1-4.
L is an auxiliary ligand, a substituted or unsubstituted aryl group having 5 to 50 nuclear carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear carbon atoms, or a substituted or unsubstituted nuclear carbon number 4 ˜50 heterocyclic groups.
M is an element contained in Group 1, Group 2, Group 9, Group 10, Group 11, Group 12, or Group 13 of the Periodic Table.

Examples of the alkyl group represented by R ^{1 to} R ¹² in the general formulas (I) and (II) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a s-butyl group, a t-butyl group, and a pentyl group. Hexyl group, heptyl group, octyl group, stearyl group, 2-phenylisopropyl group, trichloromethyl group, trifluoromethyl group, benzyl group, α-phenoxybenzyl group, α, α-dimethylbenzyl group, α, α-methyl Examples include phenylbenzyl group, α, α-ditrifluoromethylbenzyl group, triphenylmethyl group, α-benzyloxybenzyl group and the like.
Examples of the aryl group represented by R ^{1 to} R ¹² and L in the general formulas (I) and (II) include a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, and 4-ethylphenyl. Group, biphenyl group, 4-methylbiphenyl group, 4-ethylbiphenyl group, 4-cyclohexylbiphenyl group, terphenyl group, 3,5-dichlorophenyl group, naphthyl group, 5-methylnaphthyl group, anthryl group, pyrenyl group, etc. Can be mentioned.

Examples of the aralkyl group of R ^{1 to} R ¹² in the general formulas (I) and (II) include a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a 1-phenylisopropyl group, a 2-phenylisopropyl group, Phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, 2-β-naphthylisopropyl group, 1-pyrrolylmethyl group, 2- (1-pyrrolyl) ethyl group, p- Methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group, p Bromobenzyl group, m-bromobenzyl group, o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl Group, p-aminobenzyl group, m-aminobenzyl group, o-aminobenzyl group, p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group, o-Cyanobenzyl group, 1-hydroxy-2-phenylisopropyl group, 1-chloro-2-phenylisopropyl group and the like can be mentioned.

Examples of the cycloalkyl group represented by R ^{1 to} R ¹² in the general formulas (I) and (II) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a bicyclo group. A heptyl group, a bicyclooctyl group, a tricycloheptyl group, an adamantyl group and the like can be mentioned. A cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a bicycloheptyl group, a bicyclooctyl group and an adamantyl group are preferable.
Examples of the alkoxyl group of R ^{1 to} R ¹² include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, various pentyloxy groups, and various hexyloxy groups. Groups and the like.
The general formula (I) and (II) in R ¹ to R ¹² and L aryloxy group include phenoxy group, tolyloxy group, naphthyloxy group and the like.

Examples of the arylamino group of R ^{1 to} R ¹² in the general formulas (I) and (II) include a diphenylamino group, a ditolylamino group, a dinaphthylamino group, and a naphthylphenylamino group.
Examples of the alkylamino group of R ^{1 to} R ¹² in the general formulas (I) and (II) include a dimethylamino group, a diethylamino group, and a dihexylamino group.
Examples of the heterocyclic group of R ^{1 to} R ¹² and L in the general formulas (I) and (II) include imidazole, benzimidazole, pyrrole, furan, thiophene, benzothiophene, oxadiazoline, indoline, carbazole, pyridine, Residues such as quinoline, isoquinoline, benzoquinone, pyrarodine, imidazolidine, piperidine, hydroxyquinoline derivative, phenylpyridine derivative and the like can be mentioned.
As a halogen atom of R < ¹ > -R < ¹² > in general formula (I) and (II), a fluorine atom, a chlorine atom, a bromine atom etc. are mentioned, for example.

Moreover, as a substituent of each group represented by R < ¹ > -R < ¹² > and L in the said general formula (I) and (II), a C1-C10 alkyl group and a C1-C10 alkoxy group are preferable, A C1-C10 alkyl group is more preferable. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, cyclopentyl group, n-hexyl group, and cyclohexyl group are included. Particularly preferred.

  M in the general formulas (I) and (II) is an element included in Group 1, Group 2, Group 9, Group 10, Group 11, Group 12, or Group 13 of the periodic table, preferably Li, Be, Ir, Pt, Cu, Zn, or Al, particularly preferably Pt, Zn, or Al.

  Specific examples of the metal complex compound having a specific structure represented by the general formula (I) or (II) are shown below, but are not limited to these exemplified compounds.

The organic EL element of the present invention will be described in detail below.
(1) Configuration of Organic EL Element A typical configuration example of the organic EL element used in the present invention is shown below. Of course, the present invention is not limited to this.
(1) Anode / hole transport layer / light emitting layer / cathode
(2) Anode / light emitting layer / electron transport layer / cathode
(3) Anode / hole transport layer / light emitting layer / electron transport layer / cathode
(4) Anode / hole transport layer / light emitting layer / adhesion improving layer / cathode
(5) Anode / insulating layer / hole transporting layer / light emitting layer / electron transporting layer / cathode
(6) Anode / hole transport layer / light emitting layer / electron transport layer / insulating layer / cathode
(7) Anode / inorganic semiconductor layer / insulating layer / hole transporting layer / light emitting layer / insulating layer / cathode
(8) Structures of anode / insulating layer / hole transporting layer / light emitting layer / electron transporting layer / insulating layer / cathode can be mentioned. Of these, the structure of (3), (5) or (6) is preferably used.
The metal complex compound of the present invention may be used in any of the organic layers described above, but is preferably contained as a light-emitting material, an electron injection material, or an electron transport material in these constituent elements. Particularly preferred is the case where it is contained in the light emitting layer. The amount to be contained is selected from 30 to 100 mol%.

(2) Translucent substrate The organic EL device of the present invention is produced on a translucent substrate. Here, the translucent substrate is a substrate that supports the organic EL element, and is preferably a smooth substrate that has a light transmittance of 50% or more in the visible region with a wavelength of 400 to 700 nm.
Specifically, a glass plate, a polymer plate, etc. are mentioned. Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

(3) Anode The anode of the organic thin film EL element plays a role of injecting holes into the hole transport layer or the light emitting layer, and it is effective to have a work function of 4.5 eV or more. Specific examples of the anode material used in the present invention include indium tin oxide alloy (ITO), indium zinc oxide alloy (IZO), tin oxide (NESA), gold, silver, platinum, copper, and the like. Moreover, you may use these alloys and laminated bodies.
The anode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.
Thus, when light emission from the light emitting layer is taken out from the anode, it is preferable that the transmittance of the anode for light emission is greater than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. Although the film thickness of the anode depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

(4) Light emitting layer The light emitting layer of an organic EL element has the following functions. That is,
(1) Injection function: Function that can inject holes from the anode or hole injection layer when an electric field is applied, and can inject electrons from the cathode or electron injection layer
(2) Transport function: Function to move injected charges (electrons and holes) by the force of electric field
(3) Light-emitting function: Provides a field for recombination of electrons and holes, and has a function to connect this to light emission. However, there may be a difference between the ease of hole injection and the ease of electron injection, and the transport capability represented by the mobility of holes and electrons may be large or small. It is preferable to move the charge.

As a method for forming the light emitting layer, for example, a known method such as an evaporation method, a spin coating method, or an LB method can be applied. The light emitting layer is particularly preferably a molecular deposited film.
Here, the molecular deposited film is a thin film formed by deposition from a material compound in a gas phase state or a film formed by solidifying from a material compound in a solution state or a liquid phase state. Can be classified from a thin film (accumulated film) formed by the LB method according to a difference in an agglomerated structure and a higher-order structure and a functional difference resulting therefrom.
Further, as disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, and then this is thinned by a spin coating method or the like. In addition, a light emitting layer can be formed.
In the present invention, a known light emitting material other than the light emitting material comprising the metal complex compound of the present invention may be contained in the light emitting layer as desired, as long as the object of the present invention is not impaired. A light emitting layer containing another known light emitting material may be stacked on a light emitting layer containing a light emitting material made of a metal complex compound.

  Examples of the light emitting material or doping material that can be used in the light emitting layer together with the metal complex compound of the present invention include naphthalene, phenanthrene, rubrene, anthracene, tetracene, pyrene, perylene, chrysene, decacyclene, coronene, tetraphenylcyclopentadiene, pentaphenylcyclopentaene. Fused polycyclic aromatic compounds such as pentadiene, fluorene, spirofluorene, 9,10-diphenylanthracene, 9,10-bis (phenylethynyl) anthracene, 1,4-bis (9′-ethynylanthracenyl) benzene, and the like Derivatives, organometallic complexes such as tris (8-quinolinolato) aluminum, bis- (2-methyl-8-quinolinolato)-(4-phenylphenolato) aluminum, phthalocyanine derivatives, porphyrin derivatives, Arylamine derivatives, styrylamine derivatives, stilbene derivatives, coumarin derivatives, pyran derivatives, oxazone derivatives, benzothiazole derivatives, benzoxazole derivatives, benzimidazole derivatives, pyrazine derivatives, cinnamic acid ester derivatives, diketopyrrolopyrrole derivatives, acridone derivatives, Examples thereof include, but are not limited to, quinacridone derivatives.

(5) Hole injection and transport layer The hole transport layer is a layer that assists hole injection into the light emitting layer and transports it to the light emitting region, and has a high hole mobility. As such a hole injection and transport layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable. Further, when an electric field is applied with a hole mobility of, for example, 10 ⁴ to 10 ⁶ V / cm, At least 10 ⁻⁴ cm ² / V · sec is preferable. As the compound used for the hole transport layer and the injection layer, any of those conventionally used as a charge transport material for holes in optical transmission materials and known compounds used for the hole injection layer of EL elements can be used. Can be selected and used. However, most of the compounds used in the hole transport layer and the injection layer that have been used so far have a small ionization energy of 5.5 eV or less, but the above-mentioned hydrocarbon-based light-emitting materials usually have an ionization energy of 5. Since it is as large as 6 to 5.8 eV, it is necessary to use a material having a particularly high ionization energy and close to the ionization potential of the material used for the light emitting layer as the material for the hole transport layer and injection layer used in the present invention. The difference in ionization potential between the hole transport layer / injection layer material and the material used for the light emitting layer is preferably 0.2 eV or less, more preferably 0.1 eV or less. The material to be used is not particularly limited as long as it has the above preferable properties, and any material can be selected and used from the compounds described below.

  Specific examples include, for example, triazole derivatives (see US Pat. No. 3,112,197), oxadiazole derivatives (see US Pat. No. 3,189,447, etc.), imidazole derivatives (Japanese Patent Publication No. 37-16096). Polyarylalkane derivatives (US Pat. Nos. 3,615,402, 3,820,989, 3,542,544, JP-B-45-555). 51-10983, JP-A-51-93224, 55-17105, 56-4148, 55-108667, 55-156953, 56-36656 Patent Publication etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. Nos. 3,180,729 and 4,278,746) JP, 55-88064, 55-88065, 49-105537, 55-51086, 56-80051, 56-88141, 57-45545. Gazette, 54-112737, 55-74546, etc.), phenylenediamine derivatives (US Pat. No. 3,615,404, JP-B 51-10105, 46-3712, 47-25336, JP-A 54-53435, 54-110536, 54-1119925, etc.), arylamine derivatives (US Pat. No. 3,567,450), 3,180,703, 3,240,597, 3,658,520, 4,232,1 No. 3, No. 4,175,961, No. 4,012,376, JP-B No. 49-35702, No. 39-27577, JP-A No. 55-144250 56-119132, 56-22437, West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501, etc.), Oxazole derivatives (disclosed in US Pat. No. 3,257,203, etc.), styryl anthracene derivatives (see JP 56-46234 A, etc.), fluorenone derivatives (see JP 54-110837 A, etc.) ), Hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143, 55-52063, 55-52064). No. 55-46760, No. 55-85495, No. 57-11350, No. 57-148799, JP-A-2-311591, etc.), Stilbene derivatives (JP-A 61-61). No. 210363, No. 61-228451, No. 61-14642, No. 61-72255, No. 62-47646, No. 62-36674, No. 62-10652, No. 62- 30255, 60-94455, 60-94462, 60-174749, 60-175052, etc.), silazane derivatives (US Pat. No. 4,950,950) , Polysilanes (JP-A-2-204996), aniline copolymers (JP-A-2-282263), JP-A-1 Conductive polymer oligomers disclosed in 211399 JP can (particularly thiophene oligomer).

The hole transport layer may be provided with a separate hole injection layer to further assist hole injection. As the material for the hole injection layer, the same material as that for the hole transport layer can be used, but a porphyrin compound (disclosed in Japanese Patent Laid-Open No. 63-295965), an aromatic tertiary amine compound, and Styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 54-149634, 54-64299, 55-79450 No. 55-144250, No. 56-119132, No. 61-295558, No. 61-98353, No. 63-295695, etc.), Hexaazaphenylene derivatives (Special Table 2003) 519432) can also be used.
Further, for example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule. (Hereinafter abbreviated as NPD), and 4,4 ′, 4 ″ -tris (N- (3−3) in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. And methylphenyl) -N-phenylamino) triphenylamine (hereinafter abbreviated as MTDATA).

In addition to aromatic dimethylidin compounds, inorganic compounds such as p-type Si and p-type SiC can also be used as the material for the hole injection layer.
The hole injection and transport layer can be formed by thinning the above-described compound by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. The thickness of the hole injection or transport layer is not particularly limited, but is usually 5 nm to 5 μm. As long as this hole injection and transport layer contains the compound of the present invention in the hole transport zone, it may be composed of one or more of the above materials, or the hole injection, A layer in which a hole injection / transport layer made of a compound different from the transport layer is laminated may be used.
The organic semiconductor layer is also a part of the hole transport layer, which is a layer that assists hole injection or electron injection into the light emitting layer, and preferably has a conductivity of 10 ⁻¹⁰ S / cm or more. It is. As a material for such an organic semiconductor layer, a conductive oligomer such as a thiophene-containing oligomer, an arylamine oligomer disclosed in JP-A-8-193191, a conductive dendrimer such as an arylamine dendrimer, or the like is used. Can do.

(6) Electron injection and transport layer The electron transport layer is a layer that assists the injection of electrons into the light emitting layer and has a high electron mobility.
In organic EL, since emitted light is reflected by an electrode (in this case, a cathode), it is known that light emitted directly from the anode interferes with light emitted via reflection by the electrode. In order to efficiently use this interference effect, the electron transport layer is appropriately selected with a film thickness of several nanometers to several micrometers, but particularly when the film thickness is large, 10 ⁴ to 10 ⁶ V / It is desirable that the electron mobility is at least 10 ⁻⁵ cm ² / Vs or more when an electric field of cm is applied. As the material used for the electron transport layer, various compounds as described below can be used, but many of the compounds for the electron transport layer that have been used so far have an affinity level of about 3.0 eV. In the present invention, in order to reduce the voltage, it is necessary to make the electron barrier remarkably small by making the affinity levels of the materials used for the electron transport layer and the light emitting layer close to each other. Therefore, as the material for the electron transport layer used in the present invention, it is necessary to select a material having an affinity level close to the affinity level (about 2.6 to 2.8 eV) of the hydrocarbon-based light emitting material. The difference in affinity level between the materials used for the electron transport layer and the light emitting layer is preferably 0.2 eV or less, more preferably 0.1 eV or less. The compound used for the electron transport layer is not particularly limited as long as it has the above-mentioned preferable properties, and can be selected from the compounds described below.

Specific examples thereof include a metal complex of 8-hydroxyquinoline or a derivative thereof. Specific examples of the metal complex of 8-hydroxyquinoline or its derivative include metal chelate oxinoid compounds containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline).
For example, tris (8-quinolinolato) aluminum (Alq) described in the light emitting material can be used as a material for the electron injection layer.

（式中、Ａｒ¹、Ａｒ²、Ａｒ³、Ａｒ⁵、Ａｒ⁶、及びＡｒ⁹はそれぞれ置換もしくは無置換のアリール基を示し、それぞれ互いに同一であっても異なっていてもよい。またＡｒ⁴、Ａｒ⁷、及びＡｒ⁸は置換もしくは無置換のアリーレン基を示し、それぞれ同一であっても異なっていてもよい） On the other hand, examples of the oxadiazole derivative include electron transfer compounds represented by the following general formula.

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁵ , Ar ⁶ , and Ar ⁹ each represent a substituted or unsubstituted aryl group, and may be the same or different from each other. Ar ⁴ , Ar ⁷ and Ar ⁸ represent a substituted or unsubstituted arylene group, which may be the same or different.

Examples of the aryl group in the above formula include a phenyl group, a biphenyl group, an anthranyl group, a perylenyl group, and a pyrenyl group. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthranylene group, a peryleneylene group, and a pyrenylene group. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a cyano group. This electron transfer compound is preferably a thin film-forming compound.
Specific examples of the electron transfer compound include the following.

Further, a nitrogen-containing heterocyclic derivative represented by the following general formula (3A) or (3B) is also suitable as an electron transporting material.

{Wherein A ^{1 to} A ³ are a nitrogen atom or a carbon atom, and R is a substituted or unsubstituted aryl group having 6 to 60 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 60 carbon atoms. , An alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. n is an integer of 0 to 5, and when n is an integer of 2 or more, a plurality of R may be the same or different from each other.
A plurality of adjacent R groups may be bonded to each other to form a substituted or unsubstituted carbocyclic aliphatic ring or a substituted or unsubstituted carbocyclic aromatic ring. Ar ¹⁰ is a substituted or unsubstituted aryl group having 6 to 60 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 60 carbon atoms, Ar ¹¹ is a hydrogen atom, an alkyl having 1 to 20 carbon atoms A group, a haloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 60 carbon atoms. is there.
(However, any one of Ar ¹⁰ and Ar ¹¹ is a substituted or unsubstituted condensed ring group having 10 to 60 carbon atoms, or a substituted or unsubstituted hetero condensed ring group having 3 to 60 carbon atoms.)
L ¹ and L ² are each a single bond, a substituted or unsubstituted condensed ring having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic ring having 3 to 60 carbon atoms, or a substituted or unsubstituted fluorenylene group. }

A nitrogen-containing heterocyclic derivative represented by the following general formula (4) is suitable as an electron transport material (Japanese Patent Application No. 2003-004139).
HAr-L ¹ -Ar ¹ -Ar ² (4)
(In the formula, HAr is a substituted or unsubstituted nitrogen-containing heterocycle having 3 to 40 carbon atoms, and L ¹ is a single bond, a substituted or unsubstituted arylene group having 6 to 60 carbon atoms, substituted or unsubstituted. A heteroarylene group having 3 to 60 carbon atoms or a substituted or unsubstituted fluorenylene group, Ar ¹ is a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and Ar ² is A substituted or unsubstituted aryl group having 6 to 60 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 60 carbon atoms.)

（式中、Ｘ及びＹは、それぞれ独立に炭素数１から６までの飽和もしくは不飽和の炭化水素基、アルコキシ基、アルケニルオキシ基、アルキニルオキシ基、ヒドロキシ基、置換もしくは無置換のアリール基、置換もしくは無置換のヘテロ環又はＸとＹが結合して飽和又は不飽和の環を形成した構造であり、Ｒ₁₃ 〜Ｒ₁₆は、それぞれ独立に水素、ハロゲン、置換もしくは無置換の炭素数１から６までのアルキル基、アルコキシ基、アリールオキシ基、パーフルオロアルキル基、パーフルオロアルコキシ基、アミノ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アゾ基、アルキルカルボニルオキシ基、アリールカルボニルオキシ基、アルコキシカルボニルオキシ基、アリールオキシカルボニルオキシ基、スルフィニル基、スルフォニル基、スルファニル基、シリル基、カルバモイル基、アリール基、ヘテロ環基、アルケニル基、アルキニル基、ニトロ基、ホルミル基、ニトロソ基、ホルミルオキシ基、イソシアノ基、シアネート基、イソシアネート基、チオシアネート基、イソチオシアネート基もしくはシアノ基又は隣接した場合には置換もしくは無置換の環が縮合した構造である。） An electroluminescent device using a silacyclopentadiene derivative represented by the following general formula as an electron transporting material has also been proposed (Japanese Patent Laid-Open No. 09-087616).

(Wherein X and Y are each independently a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group, an alkenyloxy group, an alkynyloxy group, a hydroxy group, a substituted or unsubstituted aryl group, It is a structure in which a substituted or unsubstituted hetero ring or X and Y are combined to form a saturated or unsaturated ring, and R _{13 to} R ₁₆ are each independently hydrogen, halogen, substituted or unsubstituted carbon number 1 To 6 alkyl groups, alkoxy groups, aryloxy groups, perfluoroalkyl groups, perfluoroalkoxy groups, amino groups, alkylcarbonyl groups, arylcarbonyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, azo groups, alkylcarbonyloxy Group, arylcarbonyloxy group, alkoxycarbonyloxy group, aryloxy Carbonyloxy group, sulfinyl group, sulfonyl group, sulfanyl group, silyl group, carbamoyl group, aryl group, heterocyclic group, alkenyl group, alkynyl group, nitro group, formyl group, nitroso group, formyloxy group, isocyano group, cyanate group , An isocyanate group, a thiocyanate group, an isothiocyanate group or a cyano group, or, when adjacent, a substituted or unsubstituted ring is condensed.)

（式中、Ｒ₁₇〜Ｒ₂₄およびＺ₂は、それぞれ独立に、水素原子、飽和もしくは不飽和の炭化水素基、芳香族基、ヘテロ環基、置換アミノ基、置換ボリル基、アルコキシ基またはアリールオキシ基を示し、Ｘ₁、Ｙ₁およびＺ₁は、それぞれ独立に、飽和もしくは不飽和の炭化水素基、芳香族基、ヘテロ環基、置換アミノ基、アルコキシ基またはアリールオキシ基を示し、Ｚ₁とＺ₂の置換基は相互に結合して縮合環を形成してもよく、ｎは１〜３の整数を示し、ｎが２以上の場合、Ｚ₁は異なってもよい。但し、ｎが１、Ｘ₁、Ｙ₁およびＲ₁₈がメチル基であって、Ｒ₂₄が水素原子または置換ボリル基の場合、およびｎが３でＺ₁がメチル基の場合を含まない。） An electroluminescent device using a borane derivative represented by the following general formula as an electron transport material has also been proposed (Japanese Patent Publication No. 2000-040586).

(Wherein R _{17 to} R ₂₄ and Z ₂ are each independently a hydrogen atom, a saturated or unsaturated hydrocarbon group, an aromatic group, a heterocyclic group, a substituted amino group, a substituted boryl group, an alkoxy group or an aryl group) X ₁ , Y ₁ and Z ₁ each independently represents a saturated or unsaturated hydrocarbon group, aromatic group, heterocyclic group, substituted amino group, alkoxy group or aryloxy group; The substituents of ₁ and Z ₂ may be bonded to each other to form a condensed ring, n represents an integer of 1 to 3, and when n is 2 or more, Z ₁ may be different, provided that n 1, X ₁ , Y ₁ and R ₁₈ are methyl groups, R ₂₄ is a hydrogen atom or a substituted boryl group, and n is 3 and Z ₁ is a methyl group.

［式中、Ｑ¹及びＱ²は、それぞれ独立に下記一般式（６）で表される配位子

｛式中、環Ａ¹及びＡ²は、置換もしくは無置換の互いに縮合した６員アリール環構造である｝
を表し、Ｌはハロゲン原子、置換もしくは未置換のアルキル基、置換もしくは未置換のシクロアルキル基、置換もしくは未置換のアリール基、置換もしくは未置換の複素環、−ＯＲ¹
｛Ｒ¹は水素原子、置換もしくは未置換のアルキル基、置換もしくは未置換のシクロアルキル基、置換もしくは未置換のアリール基、置換もしくは未置換の複素環基である。｝
又は−Ｏ−Ｇａ−Ｑ³（Ｑ⁴）
｛Ｑ³及びＱ⁴はＱ¹及びＱ²と同じ意味を表す。｝
で示される配位子を表す。］ An organic gallium compound represented by the following general formula (5) has also been proposed as an electron injection material (Japanese Patent Laid-Open No. 10-088121).

Wherein Q ¹ and Q ² are each independently a ligand represented by the following general formula (6)

{Wherein rings A ¹ and A ² are substituted or unsubstituted 6-membered aryl ring structures fused together}
L represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocycle, —OR ¹
{R ¹ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. }
Or -O-Ga-Q ³ (Q ⁴ )
{Q ³ and Q ⁴ represent the same meaning as Q ¹ and Q ² . }
Represents a ligand represented by ]

Residues of the general formula (6) represented by Q ¹ to Q ⁴ is 8-hydroxyquinoline, is quinoline residue such as 2-methyl-8-hydroxyquinoline, but not limited thereto.
Rings A ¹ and A ² represented by the general formula (6) are substituted or unsubstituted aryl rings or heterocyclic structures bonded to each other. This metal complex has strong properties as an n-type semiconductor and has a large electron injection capability. Furthermore, since the generation energy at the time of complex formation is also low, the bond between the metal of the formed metal complex and the ligand is strengthened, and the fluorescence quantum efficiency as a light emitting material is also increased. Specific examples of the substituents of the rings A ¹ and A ² that form the ligand of the general formula (6) include chlorine, bromine, iodine, halogen atoms of fluorine, methyl group, ethyl group, propyl group, Substituted or unsubstituted alkyl groups such as butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, trichloromethyl group, phenyl group, naphthyl group, 3-methyl A substituted or unsubstituted aryl group such as phenyl group, 3-methoxyphenyl group, 3-fluorophenyl group, 3-trichloromethylphenyl group, 3-trifluoromethylphenyl group, 3-nitrophenyl group, methoxy group, n- Butoxy group, t-butoxy group, trichloromethoxy group, trifluoroethoxy group, pentafluoropropoxy group, 2,2,3,3-tetrafluoro Substituted or unsubstituted alkoxy groups such as lopropoxy group, 1,1,1,3,3,3-hexafluoro-2-propoxy group, 6- (perfluoroethyl) hexyloxy group, phenoxy group, p-nitrophenoxy Group, p-t-butylphenoxy group, 3-fluorophenoxy group, pentafluorophenyl group, substituted or unsubstituted aryloxy group such as 3-trifluoromethylphenoxy group, methylthio group, ethylthio group, t-butylthio group, Substituted or unsubstituted alkylthio groups such as hexylthio group, octylthio group, trifluoromethylthio group, phenylthio group, p-nitrophenylthio group, pt-butylphenylthio group, 3-fluorophenylthio group, pentafluorophenylthio Substitution of 3-group, 3-trifluoromethylphenylthio group, etc. Or an unsubstituted arylthio group, cyano group, nitro group, amino group, methylamino group, diethylamino group, ethylamino group, diethylamino group, dipropylamino group, dibutylamino group, diphenylamino group, or other mono- or disubstituted amino group Group, acylamino group such as bis (acetoxymethyl) amino group, bis (acetoxyethyl) amino group, bisacetoxypropyl) amino group, bis (acetoxybutyl) amino group, hydroxyl group, siloxy group, acyl group, methylcarbamoyl group, dimethyl group A carbamoyl group such as a carbamoyl group, an ethylcarbamoyl group, a diethylcarbamoyl group, a propylcarbamoyl group, a butylcarbamoyl group, and a phenylcarbamoyl group, a cycloalkyl group such as a carboxylic acid group, a sulfonic acid group, an imide group, a cyclopentane group, and a cyclohexyl group Kill group, phenyl group, naphthyl group, biphenyl group, anthranyl group, phenanthryl group, fluorenyl group, pyrenyl group and other aryl groups, pyridinyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, triazinyl group, indolinyl group, quinolinyl group, acridinyl Group, pyrrolidinyl group, dioxanyl group, piperidinyl group, morpholidinyl group, piperazinyl group, triatinyl group, carbazolyl group, furanyl group, thiophenyl group, oxazolyl group, oxadiazolyl group, benzoxazolyl group, thiazolyl group, thiadiazolyl group, benzothiazolyl Groups, triazolyl groups, imidazolyl groups, benzoimidazolyl groups, and heterocyclic groups such as pranyl groups. Moreover, the above substituents may combine to form a further 6-membered aryl ring or heterocyclic ring.

  In a preferred embodiment of the present invention, there is an element containing a reducing dopant in an electron transporting region or an interface region between a cathode and an organic layer. Here, the reducing dopant is defined as a substance capable of reducing the electron transporting compound. Accordingly, various materials can be used as long as they have a certain reducibility, such as alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metals. At least selected from the group consisting of oxides, alkaline earth metal halides, rare earth metal oxides or rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, rare earth metal organic complexes One substance can be preferably used.

  More specifically, preferable reducing dopants include Na (work function: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2.16 eV) and Cs (work function: 1 .95 eV), at least one alkali metal selected from the group consisting of Ca (work function: 2.9 eV), Sr (work function: 2.0 to 2.5 eV), and Ba (work function: 2.52 eV). Particularly preferred are those having a work function of 2.9 eV or less, including at least one alkaline earth metal selected from the group consisting of: Of these, a more preferred reducing dopant is at least one alkali metal selected from the group consisting of K, Rb and Cs, more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and the addition of a relatively small amount to the electron injection region can improve the light emission luminance and extend the life of the organic EL element. Further, as a reducing dopant having a work function of 2.9 eV or less, a combination of these two or more alkali metals is also preferable. Particularly, a combination containing Cs, for example, Cs and Na, Cs and K, Cs and Rb, A combination of Cs, Na and K is preferred. By including Cs in combination, the reducing ability can be efficiently exhibited, and by adding to the electron injection region, the emission luminance and the life of the organic EL element can be improved.

In the present invention, an electron injection layer composed of an insulator or a semiconductor may be further provided between the cathode and the organic layer. At this time, current leakage can be effectively prevented and the electron injection property can be improved. As such an insulator, it is preferable to use at least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides. If the electron injection layer is composed of these alkali metal chalcogenides or the like, it is preferable in that the electron injection property can be further improved. Specifically, preferable alkali metal chalcogenides include, for example, Li ₂ O, K ₂ O, Na ₂ S, Na ₂ Se, and Na ₂ O, and preferable alkaline earth metal chalcogenides include, for example, CaO, BaO. , SrO, BeO, BaS, and CaSe. Further, preferable alkali metal halides include, for example, LiF, NaF, KF, LiCl, KCl, and NaCl. Examples of preferable alkaline earth metal halides include fluorides such as CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ and BeF ₂ , and halides other than fluorides.

  Further, as a semiconductor constituting the electron transport layer, an oxide containing at least one element of Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg, Si, Ta, Sb, and Zn. , Nitrides or oxynitrides, or a combination of two or more thereof. Moreover, it is preferable that the inorganic compound which comprises an electron carrying layer is a microcrystal or an amorphous insulating thin film. If the electron transport layer is composed of these insulating thin films, a more uniform thin film is formed, and pixel defects such as dark spots can be reduced. Examples of such inorganic compounds include the alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides described above.

(7) Cathode As the cathode, those having a work function (4 eV or less) metal, an alloy, an electrically conductive compound and a mixture thereof as an electrode material are used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / silver alloy, aluminum / aluminum oxide, aluminum / lithium alloy, indium, and rare earth metals.
The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.
Here, when light emitted from the light emitting layer is taken out from the cathode, it is preferable that the transmittance with respect to the light emitted from the cathode is larger than 10%.
The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

(8) Insulating layer Since organic EL applies an electric field to an ultra-thin film, pixel defects are likely to occur due to leakage or short-circuiting. In order to prevent this, it is preferable to insert an insulating thin film layer between the pair of electrodes.
Examples of materials used for the insulating layer include aluminum oxide, lithium fluoride, lithium oxide, cesium fluoride, cesium oxide, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, aluminum nitride, titanium oxide, silicon oxide, and oxide. Examples include germanium, silicon nitride, boron nitride, molybdenum oxide, ruthenium oxide, and vanadium oxide.
A mixture or laminate of these may be used.

(9) Preparation Example of Organic EL Element An anode, a light emitting layer, a hole injection layer as necessary, and an electron injection layer as necessary are formed by the materials and methods exemplified above, and an organic layer is formed by forming a cathode. An EL element can be manufactured. Moreover, an organic EL element can also be produced from the cathode to the anode in the reverse order.
Hereinafter, an example of manufacturing an organic EL device having a structure in which an anode / a hole transport layer / a light emitting layer / an electron injection layer / a cathode are sequentially provided on a translucent substrate will be described.

First, a thin film made of an anode material is formed on a suitable light-transmitting substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. Next, a hole transport layer is provided on the anode. As described above, the hole transport layer can be formed by a vacuum deposition method, a spin coating method, a casting method, an LB method, or the like, but it is easy to obtain a homogeneous film and pinholes are not easily generated. From the point of view, it is preferable to form by vacuum deposition. When forming a hole transport layer by vacuum deposition, the deposition conditions vary depending on the compound used (material of the hole transport layer), the crystal structure of the target hole injection layer, the recombination structure, etc. The source temperature is preferably selected from the range of 50 to 450 ° C., the degree of vacuum of 10 ⁻⁷ to 10 ⁻³ Torr, the deposition rate of 0.01 to 50 nm / second, the substrate temperature of −50 to 300 ° C., and the thickness of 5 nm to 5 μm. .

An inorganic compound layer is formed from several nm to several tens of nm on this hole transport material. This inorganic compound layer can be formed by various methods, and specifically, vacuum deposition, sputtering, electron beam deposition, and the like. When an inorganic compound layer is formed by vacuum deposition, the deposition conditions vary depending on the compound used (the material of the hole transport layer), the crystal structure of the target hole transport layer, the recombination structure, etc. It is preferable to appropriately select the temperature within a range of 500 to 1000 ° C., a degree of vacuum of 10 ⁻⁷ to 10 ⁻³ Torr, a deposition rate of 0.01 to 50 nm / second, a substrate temperature of −50 to 300 ° C., and a film thickness of 1 nm to 20 nm.
By repeating the formation of the hole transport layer and the inorganic compound layer in this order and multilayering the hole transport layer, the organic EL layer can be thickened to several tens to several μm. The repeating unit is not particularly limited but is preferably 2 to 10 times.

  Next, the formation of the light emitting layer on the hole transport layer is also performed by thinning the organic light emitting material by a method such as vacuum deposition, sputtering, spin coating, or casting using a desired organic light emitting material. However, it is preferably formed by a vacuum deposition method from the standpoint that a homogeneous film is easily obtained and pinholes are not easily generated. In the case of forming a light emitting layer by a vacuum vapor deposition method, the vapor deposition conditions vary depending on the compounds used, but can generally be selected from the same condition range as the hole transport layer.

Next, an electron transport layer is provided on the light emitting layer. As with the hole transport layer and the light emitting layer, it is preferable to form by a vacuum evaporation method because it is necessary to obtain a homogeneous film. Deposition conditions can be selected from the same condition ranges as the hole transport layer and the light emitting layer.
Moreover, it is also possible to make an electron carrying layer multilayer by forming an inorganic compound layer similarly to a positive hole transport layer. By making the electron transport layer multi-layered, the organic EL layer can be thickened to several tens to several μm. The repeating unit is not particularly limited but is preferably 2 to 10 times.

Finally, an organic EL element can be obtained by laminating a cathode.
The cathode is made of metal, and vapor deposition or sputtering can be used. However, vacuum deposition is preferred to protect the underlying organic layer from damage during film formation.
It is preferable that the organic EL device described so far is manufactured from the anode to the cathode consistently by a single vacuum.

The formation method of each layer of the organic EL element of the present invention is not particularly limited. Conventionally known methods such as vacuum deposition and spin coating can be used. The organic thin film layer containing the compound represented by the general formula (I) or (II) used in the organic EL device of the present invention is formed by a vacuum evaporation method, a molecular beam evaporation method (MBE method) or a solution dissolved in a solvent. It can be formed by a known method such as a dipping method, a spin coating method, a casting method, a bar coating method, or a roll coating method.
The film thickness of each organic layer of the organic EL device of the present invention is not particularly limited. Generally, if the film thickness is too thin, defects such as pinholes are likely to occur. Conversely, if it is too thick, a high applied voltage is required and the efficiency is deteriorated. Therefore, the range of several nm to 1 μm is usually preferable.
When a direct current voltage is applied to the organic EL element, light emission can be observed by applying a voltage of 5 to 40 V with the anode as + and the cathode as -polarity. In addition, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when alternating voltage is applied, uniform light emission is observed only when the anode has a positive polarity and the cathode has a negative polarity. The waveform of the alternating current to be applied may be arbitrary.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a following example, unless the summary is exceeded.

[Synthesis Examples] Str. Synthesis of (1) (1) Synthesis of 9-picolinoylfluorene synthesized in two steps as follows: A 500 mL three-necked flask was purged with nitrogen and 13.465 g of potassium t-butoxide dissolved in 100 mL of tetrahydrofuran (THF) ( 120 mmol), 8.310 g (50 mmol) of fluorene dissolved in 30 mL of THF was added and stirred for 30 minutes, then 9.072 g (60 mmol) of picolinic acid ethyl ester dissolved in 20 mL of THF was added, and heated to reflux at 70 ° C. for 24 hours. .
As a post-treatment, 100 mL of water and ether were added, neutralized with 10 mL (120 mmol) of 12M hydrochloric acid, the ether layer was taken out, and the aqueous layer was extracted twice with 100 mL of ether. These ether layers were combined, and 100 mL Washed twice with water. Then, it dried with the saturated salt solution and magnesium sulfate, the solvent was removed, and it vacuum-dried. Recrystallization was performed with 130 mL of ethanol to obtain 11.5 g of the target product (yellow solid, yield 85%). m. p. 123-124 ° C

(2) Str. Synthesis of (1) A 100 mL three-necked flask was purged with degassed nitrogen, and 2.731 g (10 mmol) of 9-picolinoylfluorene dissolved in 30 mL of THF was added. ) And heated to reflux at 70 ° C. for 24 hours. After completion of the reaction, the produced red-orange precipitate was filtered to obtain 1.5 g of a red solid (yield 25%). By measuring ¹ H-NMR spectrum (FIG. 1) and FAB-MS (Fast atom bombardment mass spectrometry, fast atom bombardment ion mass spectrum), Str. Identified as (1).

[Example 1]
A transparent electrode made of indium tin oxide having a thickness of 120 nm was provided on a glass substrate having a size of 25 × 75 × 1.1 mm. After this glass substrate was cleaned by irradiating ultraviolet rays and ozone, the substrate was placed in a vacuum deposition apparatus.
As the hole transport layer, N, N′-di (naphthalen-1-yl) -N, N′-diphenylbenzidine was deposited to a thickness of 80 nm. Next, the compound Str. (1) was deposited to a thickness of 40 nm.
Next, tris (8-hydroxyquinolinato) aluminum was deposited to a thickness of 20 nm as an electron injection layer. Next, lithium fluoride was evaporated to a thickness of 1 nm, and then aluminum was evaporated to a thickness of 150 nm. This aluminum / lithium fluoride serves as the cathode. In this way, an organic EL device was produced.
Next, when an energization test was performed on the device, red light emission with a light emission efficiency of 2.2 cd / A and 220 cd / m ² was obtained at a current density of 10 mA / cm ² . When a DC continuous current test was performed at an initial luminance of 500 cd / m ² , the luminance half time was 1,000 hours or more.

[Example 2]
In Example 1, compound Str. Instead of (1), Str. An organic EL element was produced using (2).
When an energization test was performed on this device, red light emission with a light emission efficiency of 2.0 cd / A and 200 cd / m ² was obtained at a current density of 10 mA / cm ² . When a direct current continuous current test was performed at an initial luminance of 500 cd / m ² , the luminance half time was 1,000 hours or more.

[Comparative Example 1]
In Example 1, compound Str. An organic EL device was produced using a zinc phthalocyanine complex instead of (1).
When this device was subjected to a current test, blue light emission with a light emission efficiency of 1.0 cd / A and 100 cd / cm ² was obtained at a current density of 10 mA / cm ² . When a DC continuous energization test was performed at an initial luminance of 500 cd / m ² , the luminance half time was as short as 100 hours. This is presumably because the zinc phthalocyanine complex was associated.

  As can be seen from the above results, when the metal complex compound is used in the present invention for the light emitting material of the organic EL device, the red light emitting device has a remarkable effect of high efficiency and long life.

  As described above in detail, the organic EL device using the metal complex compound of the present invention exhibits various emission hues and high heat resistance. In particular, the metal complex compound of the present invention is used as a light emitting material of the organic EL device. When used, it has a long lifetime with high light emission luminance and high light emission efficiency. For this reason, the organic EL element of the present invention has high practicality and is useful as a light source such as a flat light emitter of a wall-mounted television and a backlight of a display. It can also be used as a hole injection / transport material for organic EL devices, and further as a charge transport material for electrophotographic photoreceptors and organic semiconductors. Such an effect of the organic EL device of the present invention is remarkably exhibited particularly in a red light emitting device.

The compound Str. It is a figure which shows the < ¹ > H-NMR spectrum of (1).

Claims (10)

The metal complex compound represented by the following general formula (I).

[In General Formula (I), R ^{1 to} R ¹² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 nuclear carbon atoms, or a substituted or unsubstituted aryl group having 5 to 50 nuclear carbon atoms. Substituted or unsubstituted aralkyl group having 6 to 50 nuclear carbon atoms, substituted or unsubstituted cycloalkyl group having 5 to 50 nuclear carbon atoms, substituted or unsubstituted alkoxyl group having 1 to 50 nuclear carbon atoms, substituted or unsubstituted Substituted aryloxy group having 5 to 50 nuclear carbon atoms, substituted or unsubstituted arylamino group having 5 to 50 nuclear carbon atoms, substituted or unsubstituted alkylamino group having 1 to 20 nuclear carbon atoms, substituted or unsubstituted It is a heterocyclic group having 4 to 50 nuclear carbon atoms, a cyano group, or a halogen atom.
Adjacent ones of R ^{1 to} R ⁴ , R ^{5 to} R ⁸ , and R ^{9 to} R ¹² may be bonded to each other to form a substituted or unsubstituted cyclic structure.
m is an integer of 1 to 3, and n is an integer of 0 to 2.
L is an auxiliary ligand, a substituted or unsubstituted aryl group having 5 to 50 nuclear carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nuclear carbon atoms, or a substituted or unsubstituted nuclear carbon number 4 ˜50 heterocyclic groups.
M is an element of Group 1, Group 2, Group 9, Group 10, Group 11, Group 12, or Group 13 of the Periodic Table. ] The metal complex compound of Claim 1 represented by the following general formula (II).

[In General Formula (II), R < ¹ > -R < ¹² > and M are the same as the above, and m is 1-4. ]   In the general formula (I) or (II), M is an element of lithium (Li), beryllium (Be), iridium (Ir), platinum (Pt), copper (Cu), zinc (Zn), or aluminum (Al). The metal complex compound according to claim 1 or 2.   The metal complex compound according to claim 1, which is a material for organic electroluminescence.   In the organic electroluminescent element in which the organic thin film layer which consists of the organic thin film layer which consists of a single layer or multiple layers which has at least a light emitting layer between the cathode and the anode is sandwiched, at least one layer of the organic thin film layer contains the metal complex compound according to claim 1 or 2. An organic electroluminescence device contained alone or as a component of a mixture.   The organic electroluminescence device according to claim 5, wherein the organic thin film layer has a light emission band, and the metal complex compound is contained in the light emission band.   The organic electroluminescent element according to claim 5, wherein the metal complex compound is contained in the light emitting layer.   The organic electroluminescence device according to claim 5, wherein the organic thin film layer has an electron injection layer and / or an electron transport layer, and the metal complex compound is an electron injection material and / or an electron transport material. A ligand compound of a metal complex compound represented by the following general formula (III).

The ligand compound according to claim 9, which is a ligand of the metal complex compound according to claim 1.

Images