JP4823601B2 - Polymer light emitting material, organic electroluminescence element, and display device - Google Patents

Description

  The present invention relates to a polymer light-emitting material, an organic electroluminescence element, and a display device. More specifically, the present invention relates to a polymer light-emitting material comprising a polymer having a structural unit derived from an iridium complex, which can obtain high-luminance green to blue light with high luminous efficiency and can achieve a long lifetime, and uses thereof About.

In recent years, material development has been actively conducted in order to expand applications of organic electroluminescence elements (also referred to as organic EL elements in the present specification).
For example, a heterocyclic iridium-containing complex (see Patent Document 1) is disclosed as a green to blue phosphorescent low molecular weight compound.

  However, in the case of forming a light emitting layer by a vacuum vapor deposition method with a low molecular compound, the film thickness tends to be non-uniform and it is difficult to increase the area of the device. In addition, when a low molecular compound is dispersed in a host polymer to form a dope-type light emitting material, a light emitting layer can be formed by a coating method or the like, but the thermal stability of the element is poor, and phase separation or Prone to segregation. Therefore, such an element has a problem that the maximum reached luminance is low and the driving life is short.

  On the other hand, a polymer light-emitting material having a structural unit derived from an iridium complex coordinated with a phenylpyridine derivative and a structural unit derived from a carbazole derivative is disclosed as a material exhibiting green to blue light emission. (See Patent Documents 2 and 3).

  In such a polymer light emitting material, a light emitting layer can be formed by applying a solution containing the material, the manufacturing process of the organic EL element can be simplified and the area can be increased, and a stable element can be manufactured. it can.

However, the polymer light emitting material has a problem of short life.
In order to realize full-color display, it is necessary to use materials that emit red, green, and blue monochromatic lights, which are the three primary colors (RGB), but the light in the green to blue region is high. There has also been a problem that a polymer light emitting material that emits light efficiently has not been obtained yet.
JP2005-2053 JP 2003-206320 A JP 2002-293830 A

  An object of the present invention is to provide a high-luminance green to blue light with high luminous efficiency and a long-life polymer light-emitting material. Another object of the present invention is to provide an organic EL element and a display device that can simplify the manufacturing process and realize a large area.

As a result of earnest research to solve the above problems, the present inventors,
In order to complete the present invention, it is found that a polymer light emitting material comprising a polymer having a structural unit derived from a specific iridium complex can provide high luminance green to blue light with high luminous efficiency and a long lifetime. It came.

  That is, the present invention is summarized as follows.

[1] A polymer light emitting material comprising a polymer having a structural unit derived from an iridium complex represented by the following general formula (1).

(Wherein R ¹ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an optionally substituted phenyl group, and R ^{2 to} R ⁹ each independently represent a hydrogen atom, cyano, A group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, and L represents a bidentate ligand of a monovalent anion having a polymerizable functional group.

[2] The polymer light-emitting material according to the above [1], wherein L is a bidentate ligand represented by the following general formula (2) or (3).

(In the formula, R ¹⁰ has the same meaning as R ² in the above formula (1), and X ¹ and X ² each independently represent a polymerizable substituent.)

[3] The polymer further has a structural unit derived from at least one polymerizable compound selected from the group consisting of a hole-transporting polymerizable compound and an electron-transporting polymerizable compound. The polymer light-emitting material according to the above [1] or [2].

[4] In the organic electroluminescence device including one or more organic polymer layers sandwiched between an anode and a cathode, at least one of the organic polymer layers may include the above-mentioned [1] to [3]. An organic electroluminescence device comprising the polymer light-emitting material according to any one of the above.

  [5] An image display device using the organic electroluminescence element according to [4].

  [6] A surface-emitting light source using the organic electroluminescence device according to [4].

  According to the present invention, high-luminance green to blue light can be obtained with high luminous efficiency, and a long-life polymer light-emitting material can be provided. In addition, according to the present invention, it is possible to provide an organic EL element and a display device that can simplify the manufacturing process and realize a large area.

Hereinafter, the present invention will be specifically described.
<Polymer having a structural unit derived from an iridium complex>
The polymer light-emitting material according to the present invention comprises a polymer having a structural unit derived from a specific iridium complex, and the polymer polymerizes a monomer containing the iridium complex represented by the above formula (1). Obtained. In the present invention, the iridium complex monomers may be used singly or in combination of two or more. In this specification, the polymer includes a homopolymer of the complex and a copolymer of two or more of the complexes.

  In the polymer light emitting material, since the monomer of the iridium complex is polymerized, light emission via the triplet excited state of the iridium complex can be obtained. That is, when the polymer light emitting material is used for the light emitting layer of the organic EL element, light emission from a triplet excited state which is usually difficult to use can be obtained with high efficiency.

Since the iridium complex represented by the above formula (1) is coordinated by a ligand having a specific heterocyclic structure, a polymer light-emitting material having a high lifetime and a long lifetime can be obtained.
In the above formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group which may have a substituent.

  Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, amyl group, hexyl group, octyl group, and decyl group. (The hydrogen atom in the alkyl group may be substituted with a halogen atom).

  Examples of the substituent that the phenyl group may have include a halogen atom and a linear or branched alkyl group having 1 to 10 carbon atoms (the hydrogen atom in the alkyl group is substituted with a halogen atom). Or the like).

Of these, R ¹ is preferably a hydrogen atom, an ethyl group, or a phenyl group.
R ^{2 to} R ⁹ each independently represent a hydrogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

Examples of the alkyl group having 1 to 10 carbon atoms are the same as those for R ^1.
Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a t-butoxy group, a hexyloxy group, a 2-ethylhexyloxy group, and a decyloxy group. (The hydrogen atom in the alkoxy group may be substituted with a halogen atom).

Among these, as R < ² > -R < ⁹ >, a hydrogen atom, a cyano group, and a methoxy group are respectively independently preferable.
Among these, as R ^{1 to} R ⁹ , green to blue light is emitted with high efficiency and a long-life polymer light emitting material is obtained. Therefore, R ^{1 to} R ⁹ = hydrogen atom (the following formula (4 −1)); R ¹ = phenyl group, R ^{2 to} R ⁹ = hydrogen atom (following formula (4-2)); R ¹ = ethyl (Et) group, R ^{2 to} R ⁹ = hydrogen atom (following formula ( 4-3)); R ¹ = phenyl group, R ⁴ = cyano group, R ² , R ³ , R ^5-
R ⁹ = hydrogen atom (following formula (4-4)); and R ¹ = phenyl group, R ³ = cyano group, R ⁷ = methoxy (MeO) group, R ² , R ⁴ , R ⁵ , R ⁶ , R ^{A combination of 8} and R ⁹ = hydrogen atom (the following formula (4-5)) is preferable.

L represents a monovalent anionic bidentate ligand having a polymerizable functional group.
Examples of the bidentate ligand of the monovalent anion include, for example, a compound having a structure in which one hydrogen ion is eliminated and a conjugated structure including two coordination sites can be monovalent anionic as a whole. A compound in which one ion is eliminated to form a monovalent anion; or a nonionic coordination site such as a pyridine ring, a carbonyl group, or an imine group and a hydrogen ion such as a hydroxyl group or a carboxyl group are present in the molecule. And a compound having a moiety capable of becoming a monovalent anionic coordination site. In addition, the said ligand may have a substituent, As this substituent, it does not specifically limit, A halogen atom, a cyano group, a C1-C10 alkyl group, C1-C10 Examples thereof include an alkoxy group or a phenyl group which may have a substituent.

L has a polymerizable functional group, but preferably has one such functional group. Thereby, the structural unit derived from the iridium complex can form a side chain in the polymer.
The polymerizable functional group may be any of radical polymerizable, cationic polymerizable, anionic polymerizable, addition polymerizable, and condensation polymerizable functional groups. Of these, the radical polymerizable functional group is preferable because the production of the polymer is easy.

  Examples of the polymerizable functional group include urethane (meth) acrylate groups such as allyl group, alkenyl group, acrylate group, methacrylate group, methacryloyloxyethyl carbamate group, vinylamide group, and derivatives thereof. Of these, alkenyl groups are preferred.

  More specifically, L preferably has the functional group as a substituent represented by the following general formulas (A1) to (A12). Among these, the substituents represented by the following formulas (A1), (A5), (A8), and (A12) are more preferable because functional groups can be easily introduced into the iridium complex.

  As L, a bidentate ligand represented by the above formula (2) or (3) is preferably used. Since these ligands form a five-membered or six-membered ring structure including two atoms when two coordination sites are coordinated to one iridium atom, the ligands are stably coordinated to the atoms. it can.

X ¹ in the above formula (2) and X ² in the above formula (3) each independently represent a substituent having a polymerizable functional group. The substituent is not particularly limited in addition to having a polymerizable functional group, and may have an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or phenyl optionally having a substituent. Group and the like.

As said polymerizable functional group, it is synonymous with the polymerizable functional group in L in said Formula (1), and its preferable range is also the same.
More specifically, X ¹ and X ² are more preferably substituents represented by the above formulas (A1) to (A12), respectively. Among these, the substituents represented by the above formulas (A1), (A5), (A8), and (A12) are more preferable because the functional group can be easily introduced into the iridium complex.

R ¹⁰ in the above formula (2) has the same meaning as R ² in the above formula (1). Of these, a methyl group is preferred.
Among the iridium complexes represented by the above formula (1), specifically, since green to blue light is emitted with high efficiency and a long-life polymer light emitting material is obtained, the following formula (5-1) ) And (5-2) are particularly preferred.

The iridium complex represented by the above formula (1) is produced, for example, as follows. First, a ligand having a heterocyclic structure and sodium hexachloroiridate (0.5 equivalent) are reacted in 2-methoxyethanol (Nonoyama's method (Bull. Chem. Soc. Jpn. 1794, 47, 767.)). Subsequently, the obtained reaction product and a bidentate ligand (2 equivalents) having a polymerizable functional group are heated in 2-ethoxyethanol together with sodium carbonate, and then purified to obtain an iridium complex. (Lamansky et al. Method (Inorg. Chem. 2001, 40, 1704.)). The bidentate ligand having a polymerizable functional group can be obtained by a known method.

  The weight average molecular weight of the polymer is preferably 1,000 to 2,000,000, and more preferably 5,000 to 1,000,000. The molecular weight in this specification means the polystyrene conversion molecular weight measured using GPC (gel permeation chromatography) method. It is preferable for the molecular weight to be in this range since the polymer is soluble in an organic solvent and a uniform thin film can be obtained.

The polymer may be any of a random copolymer, a block copolymer, and an alternating copolymer.
The polymerization method of the polymer may be any of radical polymerization, cationic polymerization, anionic polymerization, and addition polymerization, but radical polymerization is preferred.
<Copolymer having a structural unit derived from a carrier transportable polymerizable compound>
The polymer used in the present invention preferably further has a structural unit derived from at least one polymerizable compound selected from the group consisting of a hole-transporting polymerizable compound and an electron-transporting polymerizable compound. . The polymer is at least one polymer selected from the group consisting of a hole transporting polymerizable compound and an electron transporting polymerizable compound together with one or more iridium complex monomers. It is obtained by copolymerizing a monomer containing a functional compound. In the present specification, the hole transport polymerizable compound and the electron transport polymerizable compound are also collectively referred to as a carrier transport polymerizable compound.

  That is, the polymer light-emitting material includes a structural unit derived from one or more hole transportable polymerizable compounds together with a structural unit derived from one or more iridium complexes, or one or more It is preferably made of a copolymer having a structural unit derived from two or more kinds of electron-transporting polymerizable compounds. In such a polymer light emitting material, holes and electrons are efficiently recombined on the structural unit derived from the iridium complex, so that high light emission efficiency is obtained.

  In addition, the polymer light-emitting material includes a structural unit derived from one or more hole transportable polymerizable compounds together with a structural unit derived from one or more iridium complexes, and one or more structural units. More preferably, it is made of a copolymer having a structural unit derived from two or more kinds of electron-transporting polymerizable compounds. In the polymer light emitting material, holes and electrons are recombined more efficiently, so that higher luminous efficiency is obtained and high maximum luminance is also obtained. Moreover, the polymer light emitting material has all the functions of light emitting property, hole transporting property, and electron transporting property, and an organic EL device can be produced without blending other organic materials. For this reason, while the manufacturing process of an organic EL element is further simplified, the organic EL element which is thermally stable and excellent in durability is obtained.

  The hole-transporting polymerizable compound and the electron-transporting polymerizable compound are not particularly limited, in addition to having the polymerizable functional group, and known carrier-transporting compounds are used.

  The polymerizable compound preferably has one polymerizable functional group. Thereby, the structural unit derived from the polymerizable compound can form a side chain in the polymer.

  The polymerizable functional group may be any of radical polymerizable, cationic polymerizable, anionic polymerizable, addition polymerizable, and condensation polymerizable functional groups. Of these, the radical polymerizable functional group is preferable because the production of the polymer is easy.

As said polymerizable functional group, it is synonymous with the polymerizable functional group in L in said Formula (1), and its preferable range is also the same.
More specifically, the polymerizable compound more preferably has the functional group as a substituent represented by the formulas (A1) to (A12).

  As the hole transport polymerizable compound, specifically, compounds represented by the following general formulas (E1) to (E6) are preferable, and since the carrier mobility in the copolymer is high, the following formula (E1) The compound represented by (E3) is more preferable.

  As the electron transport polymerizable compound, specifically, compounds represented by the following general formulas (E7) to (E14) are preferable, and since the carrier mobility in the copolymer is high, the following formula (E7) The compounds represented by (E12) to (E14) are more preferred.

  In the above formulas (E1) to (E14), compounds in which the substituents represented by the above formula (A1) are replaced with the substituents represented by the above general formulas (A2) to (A12) are also preferably used. However, a compound having a substituent represented by the above formulas (A1) and (A5) is particularly preferable because a functional group can be easily introduced into the polymerizable compound.

  Among these, as the hole transport polymerizable compound, the compound represented by any one of the above formulas (E1) to (E3), and as the electron transport polymerizable compound, the above formula (E7), It is particularly preferable to copolymerize the compound represented by any one of (E12) to (E14) in combination with the iridium complex. Such a polymer light-emitting material is desirable because it has high durability and luminous efficiency, and also has a maximum ultimate luminance. In this case, the use of the above formula (5-1) or (5-2) as the iridium complex further increases the luminous efficiency, extends the lifetime, and increases the maximum attainable luminance. preferable.

The polymerizable compound represented by the above formulas (E1) to (E14) can be produced by a known method.
The copolymer may further have a structural unit derived from another polymerizable compound. Examples of the other polymerizable compounds include compounds having no carrier transport properties such as (meth) acrylic acid alkyl esters such as methyl acrylate and methyl methacrylate, and styrene and derivatives thereof. It is not limited.

  Moreover, it is preferable that the weight average molecular weights of the said copolymer are 1,000-2,000,000, and it is more preferable that it is 5,000-1,000,000. When the molecular weight is within this range, the copolymer is soluble in an organic solvent, and a uniform thin film can be obtained.

The copolymer may be any of a random copolymer, a block copolymer, and an alternating copolymer.
In the copolymer, the number of structural units derived from the iridium complex is m, and the number of structural units derived from a carrier transporting compound (derived from a hole transporting polymerizable compound and / or an electron transporting polymerizable compound). When the total number of structural units) is n (m, n represents an integer of 1 or more), the ratio of the number of structural units derived from the iridium complex to the total number of structural units, that is, the value of m / (m + n) is It is preferably in the range of 0.001 to 0.5, and more preferably in the range of 0.001 to 0.2. When the value of m / (m + n) is in this range, an organic EL element having high luminous efficiency with high carrier mobility and low influence of concentration quenching can be obtained.

The copolymerization method may be any of radical polymerization, cationic polymerization, anionic polymerization, and addition polymerization, but radical polymerization is preferred.
<Organic EL device>
The polymer light-emitting material according to the present invention is preferably used as a material for an organic EL device. The organic EL element includes one or more organic polymer layers sandwiched between an anode and a cathode, and at least one of the organic polymer layers includes the polymer light emitting material. The polymer light emitting material according to the present invention has an advantage that a light emitting layer can be formed by a simple coating method. In addition, the polymer light-emitting material has a structural unit derived from a hole-transporting polymerizable compound and a structural unit derived from an electron-transporting polymerizable compound together with a structural unit derived from the iridium complex. When it consists of, an organic EL element can be created, without mix | blending another organic material. For this reason, the manufacturing process can be further simplified, and an element having high stability and durability can be obtained.

  An example of the configuration of the organic EL element according to the present invention is shown in FIG. 1, but the configuration of the organic EL element according to the present invention is not limited to this. In FIG. 1, a hole transport layer (3), a light emitting layer (4) and an electron transport layer (5) are arranged in this order between an anode (2) and a cathode (6) provided on a transparent substrate (1). Provided. In the organic EL device, for example, either 1) a hole transport layer / light emitting layer or 2) a light emitting layer / electron transport layer may be provided between the anode (2) and the cathode (6). In addition, 3) a layer containing a hole transport material, a light emitting material, an electron transport material, 4) a layer containing a hole transport material, a light emitting material, 5) a layer containing a light emitting material, an electron transport material, 6) Only one layer may be provided. Further, two or more light emitting layers may be stacked.

In the above, the organic polymer layer containing the polymer light-emitting material according to the present invention can be used as a light-emitting layer having both hole transport properties and electron transport properties.
Each of the above layers may be formed by mixing a polymer material or the like as a binder. Examples of the polymer material include polymethyl methacrylate, polycarbonate, polyester, polysulfone, and polyphenylene oxide.

  In addition, the light emitting material, the hole transport material, and the electron transport material used for each of the above layers may be formed independently, or may be formed by mixing materials having different functions. In the light emitting layer in the organic EL device according to the present invention, in addition to the polymer light emitting material according to the present invention, other hole transport materials and / or electron transport materials are included for the purpose of supplementing the carrier transport property of the light emitting layer. It may be. Such a transport material may be a low molecular compound or a high molecular compound.

  Examples of the hole transport material forming the hole transport layer or the hole transport material mixed with the light emitting layer include TPD (N, N′-dimethyl-N, N ′-(3-methylphenyl) -1,1 ′. -Biphenyl-4,4'diamine); α-NPD (4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl); m-MTDATA (4,4 ', 4' '- Low molecular weight triphenylamine derivatives such as tris (3-methylphenylphenylamino) triphenylamine); polyvinylcarbazole; a polymer compound obtained by polymerizing a triphenylamine derivative by introducing a polymerizable functional group; polyparaphenylene vinylene; Fluorescent light emitting polymer compounds such as polydialkylfluorene can be used. Examples of the polymer compound include a polymer compound having a triphenylamine skeleton disclosed in JP-A-8-157575. The hole transport materials may be used singly or in combination of two or more, or different hole transport materials may be laminated and used. The thickness of the hole transport layer depends on the conductivity of the hole transport layer and cannot be generally limited, but is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. .

  Examples of the electron transport material forming the electron transport layer or the electron transport material mixed with the light emitting layer include quinolinol derivative metal complexes such as Alq3 (aluminum trisquinolinolate), oxadiazole derivatives, triazole derivatives, and imidazole derivatives. And low molecular compounds such as triazine derivatives and triarylborane derivatives; and polymer compounds obtained by introducing a polymerizable substituent into the above low molecular compounds. Examples of the polymer compound include poly PBD disclosed in JP-A-10-1665. The electron transport materials may be used singly or in combination of two or more, or different electron transport materials may be laminated and used. The thickness of the electron transport layer depends on the conductivity of the electron transport layer and cannot be generally limited, but is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. .

  Further, a hole block layer may be provided adjacent to the cathode side of the light emitting layer for the purpose of suppressing holes from passing through the light emitting layer and efficiently recombining holes and electrons in the light emitting layer. Good. In order to form the hole block layer, known materials such as triazole derivatives, oxadiazole derivatives, and phenanthroline derivatives can be used.

  A buffer layer may be provided between the anode and the hole transport layer or between the anode and the organic layer stacked adjacent to the anode in order to relax the injection barrier in hole injection. In order to form the buffer layer, known materials such as copper phthalocyanine, a mixture of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) can be used.

  An insulating layer having a thickness of 0.1 to 10 nm is provided between the cathode and the electron transport layer or between the cathode and the organic layer laminated adjacent to the cathode in order to improve the electron injection efficiency. May be. In order to form the insulating layer, known materials such as lithium fluoride, magnesium fluoride, magnesium oxide, and alumina can be used.

  As an anode material used for the organic EL device according to the present invention, for example, a known transparent conductive material such as a conductive polymer such as ITO (indium tin oxide), tin oxide, zinc oxide, polythiophene, polypyrrole, and polyaniline is used. Can do. The surface resistance of the electrode formed of the transparent conductive material is preferably 1 to 50Ω / □ (ohm / square). The thickness of the anode is preferably 50 to 300 nm.

  Examples of the cathode material used in the organic EL device according to the present invention include alkali metals such as Li, Na, K, and Cs; alkaline earth metals such as Mg, Ca, and Ba; Al; MgAg alloys; AlLi, AlCa, and the like. A known cathode material such as an alloy of Al and an alkali metal can be used. The thickness of the cathode is preferably 10 nm to 1 μm, more preferably 50 to 500 nm. When a highly active metal such as an alkali metal or alkaline earth metal is used as the cathode, the thickness of the cathode is preferably 0.1 to 100 nm, more preferably 0.5 to 50 nm. In this case, a metal layer that is stable to the atmosphere is laminated on the cathode for the purpose of protecting the cathode metal. Examples of the metal forming the metal layer include Al, Ag, Au, Pt, Cu, Ni, and Cr. The thickness of the metal layer is preferably 10 nm to 1 μm, more preferably 50 to 500 nm.

  As the substrate of the organic EL device according to the present invention, an insulating substrate transparent to the emission wavelength of the light emitting material can be used. Besides glass, transparent plastics such as PET (polyethylene terephthalate) and polycarbonate are used. Can be used.

  Examples of the film formation method of the hole transport layer, the light emitting layer, and the electron transport layer include a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ink jet method, a spin coating method, a printing method, a spray method, and a dispenser method. Can be used. In the case of a low molecular compound, resistance heating vapor deposition or electron beam vapor deposition is preferably used, and in the case of a polymer material, an ink jet method, a spin coating method, or a printing method is suitably used.

  In the case of forming a light emitting layer using the polymer light emitting material according to the present invention, an inkjet method, a spin coating method, a dip coating method, or a printing method can be preferably used, so that the manufacturing process can be simplified.

  In addition, as a method for forming the anode material, for example, an electron beam evaporation method, a sputtering method, a chemical reaction method, a coating method, or the like is used. As a method for forming the cathode material, for example, a resistance heating evaporation method, An electron beam evaporation method, a sputtering method, an ion plating method, or the like is used.

The organic EL device according to the present invention is suitably used in an image display device as a matrix or segment pixel by a known method. The organic EL element is also suitably used as a surface light source without forming pixels.
<Application>
The polymer light-emitting material and organic EL device according to the present invention are suitably used for display devices, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, optical communications, and the like. It is done.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
[Example]
[Synthesis Example 1] Synthesis of Iridium Complex (5-1) Synthesis was performed as shown in Scheme 1 below. Compound (a1) 0.52 g (2.7 mmol) and sodium hexachloroiridate 0.70 g (1.3 mmol) were heated to reflux in 2-methoxyethanol for 24 hours. The obtained precipitate (b) was washed with ethanol and then heated in 2-ethoxyethanol for 15 hours together with 0.50 g (2.3 mmol) of compound (c1) and 0.30 g (2.8 mmol) of sodium carbonate. Refluxed. The obtained compound was filtered and washed with water, ethanol, ether and hexane. The residue was purified by silica gel chromatography (developing solvent: methylene chloride) and sublimated to obtain an iridium complex represented by the above formula (5-1).

Identification data of the complex (5-1) are as follows.
Elemental analysis: Calculated (C ₄₀ H ₃₃ IrN ₄ O ₂ ) C, 60.51; H, 4.19; N, 7.06. Found C, 60.27; H, 4.30; N, 7.28.
Mass spectrometry (FAB +): 794 (M ⁺ )
Abs (CH ₂ Cl ₂ ): 410 nm
PL (CH ₂ Cl ₂ ): 500 nm

[Synthesis Example 2] Synthesis of Iridium Complex (5-2) Instead of 0.52 g (2.7 mmol) of Compound (a1), a compound represented by the following formula (a2) (described in JP-A-2005-2053) 0.80 g (2.6 mmol) was used, and 0.55 g (2) of the compound represented by the following formula (c2) was used instead of 0.50 g (2.3 mmol) of compound (c1). The iridium complex represented by the above formula (5-2) was obtained in the same manner as in Synthesis Example 1 except that.

Identification data of the complex (5-2) are as follows.
Elemental analysis: Calculated (C ₅₆ H ₄₀ IrN ₇ O ₅ ) C, 62.09; H, 3.72; N, 9.05. Found C, 61.88; H, 3.80; N, 9.26.
Mass spectrometry (FAB +): 1083 (M ⁺ )
Abs (CH ₂ Cl ₂ ): 400 nm
PL (CH ₂ Cl ₂ ): 480 nm

[Example 1] Synthesis of copolymer (I) In a sealed container, 80 mg of the complex (5-1), 460 mg of the compound represented by the above formula (E2), and 460 mg of the compound represented by the above formula (E7) were added. And dehydrated toluene (9.9 ml) was added. Subsequently, a toluene solution (0.1 M, 198 μl) of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the freeze degassing operation was repeated 5 times. It sealed in vacuum and stirred at 60 ° C. for 60 hours. After the reaction, the reaction solution was dropped into 500 ml of acetone to obtain a precipitate. Further, reprecipitation purification with toluene-acetone was repeated twice, followed by vacuum drying at 50 ° C. overnight to obtain a copolymer (I).

The weight average molecular weight (Mw) of the copolymer (I) was 71500. The value of m / (m + n) was 0.030.
[Example 2] Synthesis of copolymer (II) A copolymer (II) was obtained in the same manner as in Example 1 except that the complex (5-2) was used instead of the complex (5-1). It was.

The value of m / (m + n) was 0.026.
[Example 3] Production of organic EL element and evaluation of EL emission characteristics A substrate with ITO (manufactured by Nippon Electric Co., Ltd.) was used. This was a substrate in which two ITO (indium tin oxide) electrodes (anodes) having a width of 4 mm were formed in one stripe on one surface of a 25 mm square glass substrate.

  First, poly (3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (manufactured by Bayer Co., Ltd., trade name “BYTRON P”) on the above-mentioned ITO-attached substrate under conditions of a rotation speed of 3500 rpm and a coating time of 40 seconds. Then, it was applied by spin coating. Then, it dried for 2 hours at 60 degreeC under pressure reduction with the vacuum dryer, and formed the anode buffer layer. The film thickness of the obtained anode buffer layer was about 50 nm. Next, 90 mg of copolymer (I) was dissolved in 2910 mg of toluene (special grade, manufactured by Wako Pure Chemical Industries, Ltd.), and this solution was filtered with a filter having a pore size of 0.2 μm to prepare a coating solution. Next, the coating solution was coated on the anode buffer layer by spin coating under the conditions of a rotation speed of 3000 rpm and a coating time of 30 seconds. After the application, it was dried at room temperature (25 ° C.) for 30 minutes to form a light emitting layer. The film thickness of the obtained light emitting layer was about 100 nm.

  Next, the substrate on which the light emitting layer was formed was placed in a vapor deposition apparatus. Next, calcium and aluminum were co-evaporated at a weight ratio of 1:10, and two cathodes having a width of 3 mm were formed in a stripe shape so as to be orthogonal to the extending direction of the anode. The film thickness of the obtained cathode was about 50 nm.

Finally, lead wires (wirings) were attached to the anode and the cathode in an argon atmosphere, and four organic EL elements measuring 4 mm in length and 3 mm in width were produced. A voltage was applied to the organic EL element to emit light using a programmable DC voltage / current source (TR6143, manufactured by Advantest Corporation). The emission luminance was measured using a luminance meter (BM-8, manufactured by Topcon Corporation).

The produced organic EL device showed blue-green light emission, the maximum light emission external quantum efficiency was 6.1%, and the maximum luminance was 29000 cd / m ² . In addition, when the current value was kept constant at an initial luminance of 100 cd / m ² and current was continuously supplied to emit light forcibly, it was 3400 hours until the luminance was reduced to half.
[Example 4]
An organic EL device was produced in the same manner as in Example 3 except that the copolymer (II) was used instead of the copolymer (I), and the emission color and the like were measured.

The produced organic EL device showed blue light emission, the maximum light emission external quantum efficiency was 5.0%, and the maximum luminance was 3700 cd / m ² . In addition, when the initial luminance was 100 cd / m ² , the current value was kept constant, the current was continuously supplied and the light was continuously emitted, and when it was forcibly deteriorated, it took 850 hours until the luminance was reduced to half.

FIG. 1 is a cross-sectional view of an example of an organic EL element according to the present invention.

Explanation of symbols

1: Glass substrate 2: Anode 3: Hole transport layer 4: Light emitting layer 5: Electron transport layer 6: Cathode

Claims (5)

A polymer light-emitting material comprising a polymer having a structural unit derived from an iridium complex represented by the following general formula (1).

(Wherein R ¹ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an optionally substituted phenyl group, and R ^{2 to} R ⁹ each independently represent a hydrogen atom, cyano, Represents a group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, wherein L is a bidentate ligand of a monovalent anion having a polymerizable functional group, represented by the following general formula ( It is a bidentate ligand represented by 2) or (3) .)

(Wherein R ¹⁰ has the same meaning as R ² in the formula (1), X ¹ and X ² are each independently a substituent having a polymerizable functional group, and represented by the following formula (A1) It is a substituent represented by any one of (A12) .)

The polymer is further claim 1, characterized in that it comprises structural units derived from at least one polymerizable compound selected from the group consisting of hole transport polymerizable compounds and electron transport polymerizable compound polymer light-emitting material according to. An organic electroluminescent device comprising one or more layers of the organic polymer layer sandwiched between an anode and a cathode, at least one layer of the organic polymer layer, polymer light-emitting material according to claim 1 or 2 An organic electroluminescence device comprising: The image display apparatus using the organic electroluminescent element of Claim 3 . The surface emitting light source using the organic electroluminescent element of Claim 3 .

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