JP2002235076A - Transition metal complex and light emission element material comprising the same, and light emission element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light emission element material which can be used for obtaining light emission elements capable of emitting light in high brightness, to provide the light emission element using the same, and to provide a new transition metal complex which can be used as the light emission element material. SOLUTION: The light emission element material comprises a transition metal complex comprising one or more isonitrile ligands and iridium, ruthenium or rhodium. The transition metal complex is preferably represented by formula 1 [M is indium, ruthenium or rhodium; R11 and R12 are each a substituent; n11 and n12 are each an integer of 0 to 4; L11 is a monovalent ligand]. The light emission element is characterized in that one or more layers among a light emission layer or a plurality of organic compound layers disposed between a pair of electrodes contain the light emission element material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting device which emits light by converting electric energy into light, and more particularly to a display device, a display, a backlight, an electrophotograph, an illumination light source, a recording light source, an exposure light source, a reading light source, a sign, The present invention relates to a light emitting element that can be suitably used for a signboard, an interior, an optical communication device, and the like. Further, the present invention relates to a light emitting device material used for the light emitting device and a novel transition metal complex that can be used as the light emitting device material.

[0002]

2. Description of the Related Art At present, research and development on various display elements are being actively conducted, and among them, an organic electroluminescent (EL) element has attracted attention because it can emit light with high luminance at a low voltage. For example, a light emitting device having an organic thin film formed by vapor deposition of an organic compound is known (Applied Physics Letters, 51, 913, 1987). This light emitting device has a structure in which an electron transporting material (tris (8-hydroxyquinolinato) aluminum complex (Alq)) and a hole transporting material (amine compound) are laminated, and is much larger than a conventional single-layer device. Shows improved light emission characteristics.

[0003] Orthometalated iridium complexes (Ir
(ppy) ₃ : Tris-Ortho-Metalated Complex of Iridium (I
II) A green light-emitting device having improved light-emitting characteristics by utilizing light emission from with 2-Phenylpyridine) has been reported (Applied Physics Letters, 75, 4 (1999)).
This device has an external quantum yield of 8%, which exceeds the external quantum yield of 5%, which has been regarded as the limit of the conventional device. However, improvements in light emission luminance, durability, and light emission color are required. ing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting element material used for obtaining a light emitting element capable of emitting light of high luminance and having excellent durability, a light emitting element using the same, and the light emitting element. To provide new transition metal complexes that can be used as medical materials, optical brighteners, photographic materials, UV-absorbing materials, laser dyes, dyes for color filters, color conversion filters, optical recording materials, etc. It is.

[0005]

As a result of intensive studies in view of the above-mentioned objects, the present inventors have found that a light-emitting element using a transition metal complex having a specific structure as a material for a light-emitting element can emit light with high luminance. And found that it has excellent durability,
The present invention has been made.

[0006] The material for a light emitting device of the present invention is characterized by comprising a transition metal complex containing an isonitrile ligand and a transition metal selected from the group consisting of iridium, ruthenium and rhodium.

The above transition metal complex is preferably represented by the following general formula (2).

Embedded image In the general formula (2), M is iridium, ruthenium or rhodium, R ²¹ represents a substituent, L ²¹ represents a ligand, X ²¹
Represents a counter ion. n21 represents an integer of 0 to 5;
And n23 represents an integer of 0 to 3.

The light-emitting device of the present invention has a light-emitting layer or a plurality of organic compound layers including the light-emitting layer between a pair of electrodes, and at least one of the light-emitting layer and the plurality of organic compound layers is the material for the light-emitting device. It is characterized by containing. The layer containing the light emitting element material is particularly preferably formed by a coating process.

The transition metal complex of the present invention has the following general formula:
It is characterized by being represented by (1).

Embedded image In the general formula (1), M is iridium, ruthenium or rhodium, R ¹¹ , R ¹² and R ¹³ each represent a substituent, n11
And n12 each represents an integer of 0 to 4, L ¹¹ represents a monovalent ligand. The transition metal complex can be used as a material for a light emitting device, and can be applied to medical uses, optical brighteners, photographic materials, UV absorbing materials, laser dyes, dyes for color filters, color conversion filters, optical recording materials, and the like.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [1] Material for Light Emitting Device The material for a light emitting device of the present invention comprises a transition metal complex containing an isonitrile ligand and a transition metal. The transition metal complex may include a plurality of transition metal atoms, that is, may be a so-called binuclear complex. In this case, the plurality of transition metal atoms may be the same or different. At least one of the transition metals is selected from the group consisting of iridium, ruthenium and rhodium, but may contain other metal ions at the same time. The transition metal atom is preferably iridium or ruthenium, more preferably iridium.

The transition metal complex used in the present invention may have another ligand in addition to the isonitrile ligand. Other ligands are not particularly limited. For example, Photoc by H. Yersin
hemistry and Photophysics of Coordination Compound
s ", Springer-Verlag (1987), Akio Yamamoto," Organic Metal Chemistry-Fundamentals and Applications-", and ligands described in Shokabosha (1982) can be used. Among them, halogen ligands (such as chlorine ligands), nitrogen-containing heterocyclic ligands (such as bipyridyl-based ligands, phenanthroline-based ligands, and phenylpyridine-based ligands), diketone ligands, and nitrile ligands Ligands, CO ligands, phosphorus ligands (phosphine-based ligands, phosphite-based ligands, phosphinine-based ligands, etc.), and carboxylic acid ligands (acetate-based ligands, etc.) preferable.

The transition metal complex may contain a plurality of kinds of ligands, but is preferably one to three kinds, more preferably one.
Or it contains two kinds of ligands.

The transition metal complex may be a neutral complex or an ionic complex having a counter ion. Counterion is not particularly limited, but is preferably an alkali metal ion, alkaline earth metal ions, halogen ions, perchlorate ion, PF ₆ ion, an ammonium ion (tetramethylammonium ion, etc.), borate ion or phosphonium ion, and more preferably a perchlorate ion or PF ₆ ion. The transition metal complex is preferably a neutral metal complex.

The transition metal complex used in the present invention is preferably represented by the following general formula (2), more preferably the following general formula:
It is represented by (1).

[0015]

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[0016]

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The general formula (2) will be described below. General formula
In (2), M is iridium, ruthenium or rhodium, R ²¹ has the same meaning as R ¹¹ described below, and the preferred range is also the same. L ²¹ represents a ligand, and examples of the ligand include:
Examples of the “other ligand” other than the above-mentioned isonitrile ligand include those described above. L ²¹ is preferably a halogen ligand (eg, a chlorine ligand), a nitrogen-containing heterocyclic ligand (eg, a bipyridyl-based ligand, a phenanthroline-based ligand, a phenylpyridine-based ligand), or a diketone ligand. , Nitrile ligand, CO ligand, phosphorus ligand (phosphine-based ligand, phosphite-based ligand, phosphinine-based ligand, etc.),
Or a carboxylic acid ligand (acetic acid ligand or the like). X ²¹ represents a counter ion. The counter ion X ²¹ is not particularly limited,
Preferably an alkali metal ion, alkaline earth metal ions, halogen ions, perchlorate ion, PF ₆ ion, an ammonium ion (tetramethylammonium ion, etc.), borate ion or phosphonium ion, more preferably perchlorate ion or PF ₆ It is an ion.

N21 represents an integer of 0 to 5, preferably an integer of 1 to 3. When n21 is 2 or more, a plurality of L ²¹ may be different even in the same. n22 represents an integer of 1 to 6, and is preferably an integer of 1 to 4. n22 is 2
At this time, the plurality of isonitrile ligands may be the same or different. n23 represents an integer of 0 to 3;
Or 1 is preferred. When n23 is 2 or 3, a plurality of X ²¹ may be different even in the same. n21, n2
It is preferable that 2 and n23 are a combination such that the transition metal complex used as the material for a light emitting device of the present invention becomes a neutral complex.

The general formula (1) will be described below. General formula
In (1), M is iridium, ruthenium or rhodium, and R ¹¹ , R ¹² and R ¹³ each represent a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 3 carbon atoms).
0, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, for example, methyl group, ethyl group, isopropyl group, t-butyl group, n-octyl group, n-decyl group, n-hexadecyl Group, cyclopropyl group, cyclopentyl group,
A cyclohexyl group or the like, an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, particularly preferably having 2 to 10 carbon atoms, for example, a vinyl group, an allyl group,
A butenyl group, a 3-pentenyl group and the like, an alkynyl group (preferably having a carbon number of 2 to 30, more preferably a carbon number of 2 to 20, particularly preferably a carbon number of 2 to 10, for example, a propargyl group, a 3-pentynyl group and the like) ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, for example, a phenyl group, a p-methylphenyl group, a naphthyl group, an anthryl group, a phenanthryl) Group, pyrenyl group, etc.), an amino group (preferably having 0 to 0 carbon atoms)
30, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, for example, an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, a diphenylamino group, a ditolylamino group, etc.) An alkoxy group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, particularly preferably having 1 to 10 carbon atoms, for example, a methoxy group, an ethoxy group, a butoxy group, a 2-ethylhexyloxy group, etc.) An aryloxy group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, for example, a phenyloxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, etc. ), A heteroaryloxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, a pyridyloxy group, Oxy group, pyrimidyloxy group, quinolyloxy group, etc.), acyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, acetyl group, benzoyl group, formyl Group, pivaloyl group, etc.), alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, particularly preferably having 2 to 12 carbon atoms,
For example, a methoxycarbonyl group, an ethoxycarbonyl group or the like, an aryloxycarbonyl group (preferably having 7 to 30 carbon atoms, more preferably having 7 to 20 carbon atoms, particularly preferably having 7 to 12 carbon atoms, such as a phenyloxycarbonyl group ), An acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 2 carbon atoms)
10, for example, an acetoxy group, a benzoyloxy group, etc.), an acylamino group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms).
For example, acetylamino group, benzoylamino group, etc., alkoxycarbonylamino group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, particularly preferably having 2 to 12 carbon atoms, for example, methoxycarbonyl An amino group), an aryloxycarbonylamino group (preferably having 7 to 30, more preferably 7 to 20, and particularly preferably having 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group), a sulfonylamino Groups (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, particularly preferably having 1 to 12 carbon atoms, such as a methanesulfonylamino group and a benzenesulfonylamino group), and a sulfamoyl group (preferably having a carbon number of 1). 0-30, more preferably 0-20 carbon atoms, particularly preferably 0-12 carbon atoms, such as sulfamoyl group, Rusurufamoiru group, dimethylsulfamoyl group, and phenyl sulfamoyl groups), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms
For example, a carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, a phenylcarbamoyl group or the like), an alkylthio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms)
And a arylthio group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, such as a phenylthio group), Arylthio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, a pyridylthio group, a 2-benzimidisolylthio group, a 2-benzoxazolylthio group; Group, 2-benzthiazolylthio group, etc.), sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 3 carbon atoms)
20, particularly preferably 1 to 12 carbon atoms, for example, mesyl group, tosyl group, etc., sulfinyl group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms) Such as a methanesulfinyl group and a benzenesulfinyl group), a ureido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms; Ureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 30 carbon atoms, more preferably 1 to 3 carbon atoms)
20, particularly preferably having 1 to 12 carbon atoms, for example, a diethylphosphoramide group, a phenylphosphoramide group, etc., a hydroxy group, a mercapto group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) ), A cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, Hetero atoms include a nitrogen atom, an oxygen atom, a sulfur atom and the like, and may be an aliphatic heterocyclic group or a heteroaryl group, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a thienyl group,
Piperidyl group, morpholino group, benzoxazolyl group,
A benzimidazolyl group, a benzthiazolyl group, a carbazolyl group, an azepinyl group, etc.), a silyl group (preferably having 3 to 40 carbon atoms, more preferably having 3 to 30 carbon atoms, particularly preferably having 3 to 24 carbon atoms, for example, a trimethylsilyl group, Triphenylsilyl group, etc.), phosphino group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 12 carbon atoms, for example, dimethylphosphino group, diphenylphosphino group, etc.)
And the like. These substituents may be further substituted, and the substituents may combine with each other to form a ring structure.

R ¹¹ is preferably an alkyl group or an aryl group. R ¹¹ may combine with L ¹¹ to form a chelating ligand. R ¹² and R ¹³ are each preferably an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, a fluorine atom or a substituted amino group, and more preferably an alkyl group or a fluorine atom.

L ¹¹ represents a monovalent ligand, preferably a halogen ligand, a sulfonic acid ligand, a carboxylic acid ligand,
It is an alkoxy ligand or a nitrile ligand. Also n11
And n12 each represent an integer of 0 to 4.

The transition metal complex used in the present invention preferably has a low molecular weight, but may be a so-called oligomer or polymer having a repeating unit. When the compound is an oligomer or a polymer, examples thereof include a high molecular weight compound in which the residue represented by the general formula (1) is bonded to the polymer main chain (for example, a phenylpyridine ligand in the general formula (1), R ¹¹
Or a high molecular weight compound in which L ¹¹ is bonded to the polymer main chain),
High molecular weight compounds having a skeleton represented by the general formula (1) in the main chain (for example, a phenylpyridine ligand in the general formula (1), R ¹¹
Or L ¹¹ is a high molecular weight compound contained in the polymer backbone), and the like, the weight average molecular weight (polystyrene equivalent) is preferably 1000 to 5000000, more preferably 2000 to 100000
0, particularly preferably from 3000 to 100,000. Here, the polymer may be a homopolymer, may be a copolymer with another monomer, if it is a copolymer, may be a random copolymer, may be a block copolymer .

The material for a light emitting device of the present invention comprising a transition metal complex may function as a hole injection material, a hole transport material, a light emitting material, an electron transport material, an electron injection material, etc. You may have them together. The material for a light emitting device of the present invention is preferably used as a light emitting material or a charge transport material. Hereinafter, specific examples of the transition metal complex used in the present invention are shown, but they do not limit the present invention.

[0024]

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[0025]

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[0026]

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The transition metal complex used in the present invention can be synthesized by various methods. For example, it can be obtained by mixing a ligand or a dissociated product thereof with a transition metal compound at room temperature or lower or while heating. In the case of heating, a method of heating with microwaves other than ordinary heating is also effective. If necessary, a solvent (halogen-based solvent, alcohol-based solvent, ether-based solvent, water, etc.) or a base (which may be an inorganic base or an organic base, such as sodium methoxide, potassium t-butoxide, Triethylamine, potassium carbonate, etc.).

[2] Light Emitting Element The light emitting element of the present invention has a light emitting layer or a plurality of organic compound layers including the light emitting layer between a pair of electrodes (anode and cathode). At least one of the light emitting layer and the plurality of organic compound layers contains the light emitting element material of the present invention described above. There is no particular limitation on the system, driving method, utilization form, and the like of the light emitting element of the present invention, but it is preferable that the light emitting element material of the present invention be used as a light emitting material or a charge transporting material. As a typical light emitting element, an organic EL (electroluminescence) element can be cited.

The method for forming the layer containing the material for a light emitting device of the present invention is not particularly limited, and includes a resistance heating evaporation method, an electron beam method, a sputtering method, a molecular lamination method, a coating method, and the like.
Methods such as an ink jet method, a printing method, and a transfer method can be used. Among them, the resistance heating vapor deposition method and the coating method are preferable from the viewpoint of the characteristics of the device and the production. The layer containing the light emitting element material is particularly preferably formed by a coating process.

The light emitting device of the present invention may include a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a protective layer, and the like, in addition to the light emitting layer. May be provided. As described above, the light emitting device material of the present invention may be contained in any of these layers, and is preferably contained in the light emitting layer or the charge transport layer. Hereinafter, each layer will be described in detail.

(A) Anode The anode supplies holes to the hole injection layer, the hole transport layer, the light emitting layer and the like. Materials for forming the anode include metals,
An alloy, a metal oxide, an electrically conductive compound, a mixture thereof, or the like can be used, and a material having a work function of 4 eV or more is preferably used. Specific examples include metals (gold, silver, chromium, nickel, etc.) and conductive metal oxides (tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO)
Etc.), mixtures or laminates of these metals and conductive metal oxides, inorganic conductive substances (copper iodide, copper sulfide, etc.), organic conductive materials (polyaniline, polythiophene, polypyrrole, etc.) Laminates and the like are mentioned. The anode is preferably made of a conductive metal oxide, and the productivity,
ITO is particularly preferred from the viewpoint of high conductivity, transparency and the like.

The method for forming the anode may be appropriately selected according to the material used. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating evaporation method, a chemical reaction method (such as a sol-gel method), and indium tin oxide A method such as application of a dispersion can be used. By performing a treatment such as washing on the anode, the driving voltage of the light-emitting element can be reduced or the luminous efficiency can be increased. For example, in the case of an anode made of ITO, UV-ozone treatment, plasma treatment and the like are effective. The sheet resistance of the anode is preferably several hundreds Ω / □ or less. The thickness of the anode can be appropriately selected according to the material, but is usually preferably from 10 nm to 5 μm, more preferably from 50 nm to 1 μm.
More preferably, it is particularly preferably 100 to 500 nm.

The anode is usually formed on a substrate made of soda lime glass, non-alkali glass, transparent resin or the like. In the case of a glass substrate, it is preferable to use an alkali-free glass in order to reduce ions eluted from the glass. When a soda lime glass substrate is used, it is preferable to previously form a barrier coat such as silica on the surface thereof. The thickness of the substrate is not particularly limited as long as it is sufficient to maintain mechanical strength, but in the case of a glass substrate, it is usually 0.2 mm or more, preferably 0.7 mm or more.
mm or more.

(B) Cathode The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer and the like. As the material of the cathode, metals, alloys, metal halides, metal oxides, electrically conductive compounds, mixtures thereof, and the like can be used. Adhesion with an adjacent layer such as a light emitting layer, ionization potential, and stability can be used. Etc. may be selected in consideration. Specific examples include alkali metals (Li, Na, K, etc.) and their fluorides and oxides, alkaline earth metals (Mg, Ca, etc.) and their fluorides and oxides, gold,
Alloys and mixed metals containing silver, lead, aluminum, sodium and potassium, alloys and mixed metals containing lithium and aluminum, alloys and mixed metals containing magnesium and silver, rare earth metals (such as indium and ytterbium), and mixtures thereof No. The cathode is preferably made of a material having a work function of 4 eV or less; aluminum, an alloy or a mixed metal containing lithium and aluminum,
Alternatively, it is more preferable to use an alloy or a mixed metal containing magnesium and silver.

The cathode may have a single-layer structure made of the above-described material, or may have a laminated structure including a layer made of the above-described material. For example, aluminum / lithium fluoride,
A laminated structure of aluminum / lithium oxide or the like is preferred.
The cathode can be formed by an electron beam method, a sputtering method, a resistance heating evaporation method, a coating method, or the like. In the case of a vapor deposition method, a material can be vapor-deposited alone or two or more materials can be vapor-deposited simultaneously. When an alloy electrode is formed, a plurality of metals can be formed by simultaneous evaporation, or an alloy prepared in advance may be evaporated. The sheet resistance of the cathode is preferably several hundreds Ω / □ or less.
The thickness of the cathode can be appropriately selected according to the material,
It is preferably from 10 nm to 5 μm, more preferably from 50 nm to 1 μm, particularly preferably from 100 nm to 1 μm.

(C) Hole Injection Layer and Hole Transport Layer The materials used for the hole injection layer and the hole transport layer have a function of injecting holes from the anode, a function of transporting holes, and a material injected from the cathode. Any function that has any of the functions of blocking electrons may be used. Specific examples thereof include carbazole, triazole, oxazole, oxadiazole,
Imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin -Based compounds, polysilane-based compounds, poly (N-vinylcarbazole), aniline-based copolymers, conductive polymer oligomers such as thiophene oligomers and polythiophenes, organic silanes, derivatives thereof, carbon films, materials for light emitting devices of the present invention And the like.

The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the above-mentioned materials, or a multilayer structure composed of a plurality of layers having the same composition or different compositions. Good. As a method for forming the hole injection layer and the hole transport layer, a vacuum evaporation method, an LB method, a method in which the above material is dissolved or dispersed in a solvent and coated (spin coating, casting, dip coating, etc.), An ink jet method, a printing method, a transfer method and the like are used. In the case of the coating method,
A coating solution may be prepared by dissolving or dispersing the above materials together with a resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, and polybutadiene. , Poly (N-vinylcarbazole), hydrocarbon resin,
Ketone resin, phenoxy resin, polyamide, ethyl cellulose, polyvinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin,
Epoxy resin, silicon resin and the like can be used. The thickness of the hole injection layer and the hole transport layer is not particularly limited, but is usually 1
It is preferably from 5 nm to 5 μm, more preferably from 5 nm to 1 μm, and particularly preferably from 10 to 500 nm.

(D) Light Emitting Layer When an electric field is applied to the light emitting device, holes injected from an anode, a hole injection layer or a hole transporting layer, a cathode,
The electrons injected from the electron injection layer or the electron transport layer are recombined to emit light. The material forming the light emitting layer has a function of receiving holes from an anode or the like when an electric field is applied, a function of receiving electrons from a cathode or the like, a function of transferring electric charges, and a function of emitting light by providing a field for recombination of holes and electrons. Is not particularly limited as long as it can form a layer having The material of the light-emitting layer may emit light from either a singlet exciton or a triplet exciton, and examples thereof include benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, and naphthalene. Phthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, pyrazine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compound, metal complex (8-quinolinol Derivative metal complexes, rare earth complexes, etc.), polymer light emitting materials (polythiophene, polyphenylene, polyphenylene vinylene, etc.), organic silanes, derivatives thereof, and the light emitting element material of the present invention are used. It can be.

The method for forming the light-emitting layer is not particularly limited, and includes a resistance heating evaporation method, an electron beam method, a sputtering method, a molecular lamination method, a coating method (spin coating method, casting method,
Dip coating method), inkjet method, printing method, LB
Method, transfer method and the like can be used. Among them, the resistance heating evaporation method and the coating method are preferred. The thickness of the light emitting layer is not particularly limited, and is usually preferably 1 nm to 5 μm, and preferably 5 nm.
The thickness is more preferably from 1 to 1 μm, and particularly preferably from 10 to 500 nm.

(E) Electron injection layer and electron transport layer The material forming the electron injection layer and the electron transport layer has a function of injecting electrons from the cathode, a function of transporting electrons, and a barrier against holes injected from the anode. What is necessary is just to have any of the functions. Specific examples include aromatic rings such as triazole, oxazole, oxadiazole, imidazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, naphthalene and perylene. Anhydrides, phthalocyanines, metal complexes (metal complexes of 8-quinolinol derivatives, metal phthalocyanines, metal complexes having benzoxazole or benzothiazole as ligands), organic silanes, derivatives thereof of the present invention Light emitting element materials and the like.

The electron injection layer and the electron transport layer may have a single-layer structure composed of one or more of the above-mentioned materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. Examples of the method for forming the electron injection layer and the electron transport layer include a vacuum evaporation method, an LB method, a method of dissolving or dispersing the above materials in a solvent and coating (a spin coating method, a casting method, a dip coating method, etc.), and an ink jet method. , A printing method, a transfer method and the like are used. In the case of the coating method,
The coating material may be prepared by dissolving or dispersing the above materials together with the resin component. As the resin component, the same one as in the case of the hole injection layer and the hole transport layer described above can be used.
The thickness of the electron injection layer and the electron transport layer is not particularly limited, but is usually preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 to 500 nm.

(F) Protective Layer The protective layer has a function of preventing moisture, oxygen, and the like that promotes device deterioration from entering the device. Metals (In, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni
Etc.), metal oxides (MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, Ni
O, CaO, BaO, Fe ₂ O ₃ , Y ₂ O ₃ , TiO ₂ etc.), metal fluorides (MgF ₂ , LiF, AlF ₃ , CaF ₂ etc.), nitrides (SiN, SiN _x O)
_y, etc.), polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene A copolymer obtained by copolymerizing a monomer mixture containing at least one comonomer, a fluorinated copolymer having a cyclic structure in a copolymer main chain,
A water-absorbing substance having a water absorption of 1% or more and a moisture-proof substance having a water absorption of 0.1% or less can be used.

The method for forming the protective layer is not particularly limited, and may be a vacuum deposition method, a sputtering method, a reactive sputtering method,
MBE (molecular beam epitaxy) method, cluster ion beam method, ion plating method, plasma polymerization method (high frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, Printing method, transfer method and the like can be applied.

[0044]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Comparative Example 1 40 mg of poly (N-vinylcarbazole) and 12 mg of PBD (2- (4-
Biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole) and 1 mg of the following compound A were dissolved in 2.5 ml of dichloroethane, and the resulting solution was placed on a washed substrate. An organic layer was formed by spin coating (1500 rpm, 20 sec). The thickness of the obtained organic layer was 98 nm. Next, a mask patterned so as to have a light emitting area of 4 mm × 5 mm is set on the obtained organic layer, and magnesium and silver (magnesium: silver = 10: 1 (molar ratio)) are co-deposited in a vapor deposition apparatus at 50 nm. Then, silver was further evaporated to a thickness of 50 nm to produce a light-emitting device of Comparative Example 1. To the obtained light-emitting element, a DC constant voltage is applied using Toyo Technica's “Source Measure Unit 2400” to emit light, and the emission luminance is measured by Topcon's “Brightness Meter BM-8”.
It measured using. As a result, green light was emitted, the highest luminance was 3300 cd / m ² , and the lowest driving voltage (the lowest driving voltage at which light emission was obtained) was 11 V. When the light emitting device was left in the air for one day and measured again, the highest luminance was 41.
It was 0 cd / m ² .

[0046]

[Formula 10]

Example 1 A transition metal complex (1-2) was synthesized as follows.

[Formula 11] 3.5 g of 2- (4-fluorophenyl) -pyridine and 5 g of K ₃ Ir
50 ml of 2-methoxyethanol and 30 ml of water were added to Cl ₆ and stirred under reflux. After stirring for 6 hours, the mixture was cooled to room temperature, and the precipitated yellow solid was separated by filtration to obtain 3.4 g of compound a. Subsequently, 20 ml of chloroform was added to 0.2 g of the compound a, and 0.06 ml of tC ₄ H ₉ NC was further added. The solution was stirred under reflux for 4 hours and cooled to room temperature. This was purified by silica gel column chromatography (developing solvent: chloroform), and then recrystallized from chloroform / hexane to give a solution of 0.1.
1 g of the transition metal complex (1-2) was obtained. FAB-MS spectrum (pos
i 655, 620, 572, 535) to confirm the formation of complex (1-2).

A light emitting device of Example 1 was prepared in the same manner as in Comparative Example 1 except that the transition metal complex (1-2) obtained as described above was used in place of Compound A. The light emission luminance of the obtained light emitting device was measured in the same manner as in Comparative Example 1 above. As a result, blue-green light was obtained. The maximum luminance was 3500 cd / m ² and the minimum drive voltage was 10 V. When the light-emitting element was left in the air for one day and measured again, the highest luminance was 3000 cd / m ² .

Example 2 A light emitting device was prepared in the same manner as in Comparative Example 1 using the transition metal complex (1-23) in place of the compound A. As a result, a red light emitting device having high luminance and high durability was obtained. did it.

Example 3 A light-emitting device was prepared in the same manner as in Comparative Example 1 except that 1 mg of the compound A was replaced with a mixture of the transition metal complexes (1-1) and (1-25). A durable blue-green light emitting element was obtained.

Example 4 A washed ITO substrate was placed in a vapor deposition apparatus, and TPD (N, N′-diphenyl-N, N′-di (m-tolyl) -benzidine) was vapor-deposited to a thickness of 40 nm.
On this, the following compound B and the transition metal complex (1-2) were co-evaporated at a ratio (mass ratio) of 9: 1 to 20 nm, and then the following azole compound C was evaporated to a thickness of 40 nm to form an organic thin film. Next, a mask patterned so as to have a light emitting area of 4 mm × 5 mm is set on the obtained organic thin film, and magnesium and silver (magnesium: silver = 10: 1 (mass ratio)) in a vapor deposition apparatus.
Was co-evaporated to a thickness of 50 nm, and silver was further evaporated to a thickness of 50 nm to produce a light-emitting element of Example 4. As a result of measuring the light emission luminance of the obtained light emitting device in the same manner as in Comparative Example 1, blue-green light was obtained,
The highest luminance was 2400 cd / m ² .

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[0053]

As described in detail above, the light emitting device using the light emitting device material of the present invention can emit light with high luminance, is excellent in durability, and can be obtained by appropriately selecting the light emitting device material. Various emission colors are possible. Therefore, the light emitting device of the present invention is a display device, a display, a backlight, an electrophotograph, an illumination light source, a recording light source, an exposure light source, a reading light source,
It can be suitably used for signs, signs, interiors, optical communication devices, and the like. Further, the transition metal complex forming the material for the light emitting device of the present invention is applied to medical uses, fluorescent brighteners, photographic materials, UV absorbing materials, laser dyes, color filter dyes, color conversion filters, optical recording materials, and the like. It is possible.

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Claims (5)

[Claims] 1. A light-emitting element material comprising an isonitrile ligand and a transition metal complex containing a transition metal selected from the group consisting of iridium, ruthenium and rhodium. 2. The material for a light-emitting element according to claim 1, wherein the transition metal complex is represented by the following general formula (2). Embedded image In the general formula (2), M is iridium, ruthenium or rhodium, R ²¹ represents a substituent, L ²¹ represents a ligand, X ²¹
Represents a counter ion. n21 represents an integer of 0 to 5;
And n23 represents an integer of 0 to 3. 3. A light-emitting element having a light-emitting layer or a plurality of organic compound layers including the light-emitting layer between a pair of electrodes, wherein at least one of the light-emitting layer and the plurality of organic compound layers is one or more. A light-emitting device comprising the light-emitting device material described in 1 above. 4. The light-emitting element according to claim 3, wherein the layer containing the light-emitting element material is a layer formed by a coating process. 5. A transition metal complex represented by the following general formula (1). Embedded image In the general formula (1), M is iridium, ruthenium or rhodium, R ¹¹ , R ¹² and R ¹³ each represent a substituent, n11
And n12 each represents an integer of 0 to 4, L ¹¹ represents a monovalent ligand.