JP2007031680A - Polymeric luminescent material and organic electroluminescence element using the polymeric luminescent material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymeric luminescent material which exhibits a high luminous efficiency and a long lifetime, to provide an organic EL element producible by a simplified process and capable of realizing area enlargement, and to provide a display device. <P>SOLUTION: The polymeric luminescent material comprises a polymer having structural units each derived from a metal complex containing an iridium atom or a platinum atom. More particularly, the polymeric luminescent material further comprises structural units each derived from at least one polymerizable compound selected from a hole-transporting polymerizable compound and an electron-transporting polymerizable compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polymer light-emitting material, an organic electroluminescence element using the light-emitting material, and a display device using the element. More specifically, the present invention relates to a polymer light-emitting material comprising a polymer having a structural unit derived from a metal complex, which emits light with high efficiency and can achieve a long life, and uses thereof.

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, an iridium complex having a biphenyl-based ligand (see Patent Document 1) is disclosed as a phosphorescent low-molecular compound, and an iridium complex is incorporated in poly (N-vinylcarbazole) (PVK). Dispersed doped light emitting materials (Non-Patent Document 1) and the like are also disclosed. In this doped light emitting material, an external light emission quantum efficiency of about 4% is obtained.

  However, the above materials have been required to be further improved in terms of luminous efficiency. In addition, since the complex is dispersed in the host polymer, the doped light emitting material is inferior in thermal stability and easily causes phase separation or segregation. Accordingly, there is a problem that a long-life organic EL element cannot be manufactured.

  On the other hand, for example, Patent Document 2 discloses a polymer light emitting material having a structural unit derived from an iridium complex coordinated with a phenylpyridine derivative. In such a polymer light-emitting material, a light-emitting layer can be formed by applying an organic solvent or a water solution containing the light-emitting material, thereby simplifying the manufacturing process of the organic EL element and increasing the area of the element. At the same time, a stable element can be manufactured.

However, the polymer light-emitting material has a short lifetime, and development of a polymer light-emitting material having a longer lifetime has been desired for practical use.
JP 2003-308978 A JP 2003-342325 A Jpn. J. et al. Appl. Phys. , 39, L828 (2000)

  An object of the present invention is to provide a polymer light-emitting material having high luminous efficiency and having a long lifetime. 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,
It has been found that a polymer light emitting material comprising a polymer having a structural unit derived from a specific metal complex can provide a long lifetime with high luminous efficiency, and has completed the present invention.

  That is, the present invention is summarized as follows.

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

(In the formula, M represents a metal atom having a coordination number n (n represents an integer of 4 to 6), and P and Q are each independently an aromatic group optionally having a substituent. It is a hydrocarbon group or an aromatic heterocyclic group which may have a substituent. P and Q constitute a bidentate ligand, and P and Q form a condensed ring. L ₁ is an i-dentate ligand having a polymerizable substituent (i represents a ligand conformation number and represents an integer of 1 to 4), and L ₂ is j is a ligand (where j represents the number of ligands and represents an integer of 1 to 3), X represents an anion or a counter ion of a cation, and a represents 1 or 2 represents an integer of 2, b represents an integer of 0 to 3, c represents an integer of 0 to 3, satisfies the relationship of n = 2 × a + i × 1 + j × b, and P, Q, L ₂ And X, when there are a plurality of each, May be the same or different.)

  [2] The polymer light-emitting material according to the above [1], wherein M is an iridium atom or a platinum atom.

[3] The above M is characterized in that a bidentate ligand composed of P and Q, L ₁ , and L ₂ have a bonding system of 5 coordination 16 electrons or 6 coordination 18 electrons. The polymer light-emitting material according to the above [1] or [2].

  [4] The polymer further includes 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] to [3].

  [5] In an 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 [4]. An organic electroluminescence device comprising the polymer light-emitting material according to any one of the above.

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

  [7] A surface-emitting light source using the organic electroluminescence element according to [5].

  According to the polymer light-emitting material of the present invention, it is possible to provide an organic EL element and a display device that can achieve high luminous efficiency and long life, simplify the manufacturing process, and realize a large area.

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

  In the polymer light emitting material, since the metal complex monomer is polymerized, light emission via the triplet excited state of the metal 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.

In the metal complex represented by the above formula (1), M represents a metal atom having a coordination number n. n represents an integer of 4 to 6, and n is preferably 5 or 6.
M is not particularly limited. For example, Pd, Pt, Ru, Zn, Mg, Sn, Pb, Al, Cd, Si, Ge, Ba, Sr, Be, Sc, Ti, Zr, Hf, Nb, Ta , Co, Rh, Ir, Ni, V, Cu, Ag, Ca, Hg, Mn, Fe and the like.

Of these, iridium atoms or platinum atoms are preferred because high luminous efficiency can be obtained.
P and Q are each independently an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. Constitutes a ligand. P and Q may form a condensed ring.

  Examples of the aromatic hydrocarbon group which may have a substituent include a phenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a 3-chlorophenyl group, a 3,5-dimethylphenyl group, and a diphenylaminophenyl group. Group, biphenyl group, terphenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, tolyl group, sulfophenyl group, halogen-substituted naphthyl group and the like.

  Examples of the aromatic heterocyclic group which may have a substituent include a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, an isothiazolyl group, an isoxazolyl group and the like, a 5-membered ring heterocyclic group, a pyranyl group, a pyridyl group Group, pyrazinyl group, pyrimidinyl group, pyridazinyl group and other six-membered heterocyclic groups, bipyridyl group, methylpyridyl group, tertenyl group, propylthienyl group, isobenzofuranyl group, indolizinyl group, isoindolyl group, indolyl group, indazolyl group , Purinyl group, indolinyl group, isoindolinyl group, chromenyl group, quinolidinyl group, isoquinolyl group, quinolyl group, phthalazinyl group, naphthyridinyl group, quinazolinyl group, carbazolyl group, N-ethylcarbazolyl group, thianthenyl group, phenanthridinyl group Perimidinyl group And the like.

The substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, and a tert-butyl group. Alkyl group such as octyl group, benzyl group, phenethyl group or aralkyl group; alkenyl group such as vinyl group, allyl group (2-propenyl group), 1-propenyl group, iso-propenyl group, 2-butenyl group; methoxy group Alkoxy groups such as ethoxy group, propoxy group, 2-ethyl-octyloxy group, phenoxy group, 4-butylphenoxy group, benzyloxy group; acetyl group, propionyl group, isobutyryl group, methacryloyl group, benzoyl group, naphthoyl group, Carbonyl groups such as anthroyl group and toluoyl group; methylamino group, ethylamino group, dimethyl Amino group such as amino group, diethylamino group, methylethylamino group, benzylamino group, methylbenzylamino group, anilino group, diphenylamino group, phenyltolylamino group, ditolylamino group; halogen; azo group; aryl group as described above A heterocyclic group or a condensed ring.

  Examples of the condensed ring that may be formed by P and Q include benzo, naphtho, anthra, and acenaphtho, and may include heterocycles such as furo, imidazo, pyrido, quino, and thieno. .

  Of these, as the bidentate ligand composed of P and Q, specifically, a biphenyl ligand and a phenanthrene ligand are preferable. By having such a bidentate ligand, a long lifetime is obtained with high luminous efficiency.

a represents an integer of 1 to 2, and when there are a plurality of P and Q, they may be the same as or different from each other.
L ₁ is an i-dentate ligand having a polymerizable substituent (where i represents the number of ligands and represents an integer of 1 to 4). L ₁ may be a monodentate ligand (i = 1) or a polydentate ligand (i = 2 to 2).
4), but monodentate, bidentate and tridentate ligands (i = 1 to 3) are preferred. In the above formula (1), the arrow indicates that L ₁ is monodentate or multidentate and is coordinated to M.

  Examples of the ligand include a hydroxyl group; an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a 2-ethyl-octyloxy group, a phenoxy group, a 4-butylphenoxy group, and a benzyloxy group; a phenyl group, 4 -Methylphenyl group, 4-ethylphenyl group, 3-chlorophenyl group, 3,5-dimethylphenyl group, triphenylamino group, biphenyl group, terphenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, tolyl group Aryl groups such as sulfophenyl group and halogen-substituted naphthyl group; five-membered heterocyclic groups such as thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, pyranyl group, pyridyl group, pyrazinyl Group, pyrimidinyl group, pyridazinyl group, etc. Group, bipyridyl group, methylpyridyl group, tertienyl group, propylthienyl group, isobenzofuranyl group, indolizinyl group, isoindolyl group, indolyl group, indazolyl group, purinyl group, indolinyl group, isoindolinyl group, chromenyl group, quinolidinyl group, isoquinolyl group Group, quinolyl group, phthalazinyl group, naphthyridinyl group, quinazolinyl group, carbazolyl group, N-ethylcarbazolyl group, thiantenyl group, phenanthridinyl group, perimidinyl group and the like; triphenylphosphino group, trimethylphosphine Phosphino groups such as fino group and triethylphosphino group; amino group, methylamino group, ethylamino group, dimethylamino group, diethylamino group, methylethylamino group, benzylamino group, methylbenzylamino group, anili Group, diphenylamino group, a phenyl tolyl amino group, an amino group such as diethylamino group; beta-diketones (2,4 pentanedione, etc. ethyl acetoacetate), etc. beta-diketonate group obtained by removing one proton are exemplified by. Moreover, the azo group which combined the said substituent arbitrarily may be sufficient.

  The ligand may have a substituent in addition to the polymerizable substituent, and the substituent is not particularly limited. For example, P and Q may have a substituent. Examples of the substituent are the same as those of the group.

Of these, as L ₁ , a triphenylphosphino group, a trimethylphosphino group, and a β-diketonate group are preferable.
The polymerizable substituent is not particularly limited in addition to having a polymerizable functional group moiety. For example, the substituent which is the same as the substituent which P and Q may have, and has a polymerizable functional group moiety is exemplified.

  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.

When the polymerizable functional group is an alkenyl group, L ₁ preferably has a polymerizable substituent represented by the following formulas (A1) to (A12).

Among these, the substituents represented by the above formulas (A1), (A5), and (A7) are more preferable because a polymerizable substituent can be easily introduced into the metal complex.
L ₂ is a j-dentate ligand (where j represents the number of ligands and represents an integer of 1 to 3).
L ₂ may be a monodentate ligand (i = 1) or a polydentate ligand (i = 2 to 3).
In the above formula (1), the arrow indicates that L ₂ is monodentate or multidentate and is coordinated to M.

Examples of the ligand include halogen ions such as fluorine and chlorine, thiocyanate ions, and the same ligands as L ₁ . The ligand may have a substituent, and the substituent is not particularly limited, and examples thereof include the same substituents as those which P and Q may have. It is done.

Of these, L ₂ is preferably a halogen ion, a thiocyanate ion, a hydroxyl group, a triphenylphosphino group, a trimethylphosphino group, or a β-diketonate group.

b represents an integer of 0 to 3, and when there are a plurality of L _{2 s} , they may be the same as or different from each other.
Note that L ₂ may be an oxygen atom bonded to M by a double bond instead of the bidentate ligand described above.

X represents an anion or a cation counterion.
Examples of the anion include F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , O ₂ ⁻ , (O ₂ ) ²⁻ , (O ₂ ) ⁻ , (OH) ⁻ , (SH) ⁻ , and (SO ₄ ). ) ^2- , NH ₂ ⁻ , N ³⁻ , (CN) ⁻ , (NCO) ⁻ , (NCS) ⁻ , (NO ₂ ) ⁻ , (OAc) ⁻ , (ClO ₄ ) ⁻ , (SbO ₄ ) ⁻ , (Im) ⁻ , (BF ₄ ) ^{− and the} like, and examples of the cation include, but are not limited to, K ⁺ , Na ⁺ , NH ₄ ⁺ and Li ^+. A counter ion may be used.

c represents an integer of 0 to 3, and when there are a plurality of X, they may be the same as or different from each other.
Further, the coordination number n of the metal atom M and the conformation number and number of each ligand satisfy the relationship of n = 2 × a + i × 1 + j × b.

M is preferably a bidentate ligand composed of P and Q, L ₁ , and L _2, and employs a bonding scheme of five-coordinate 16 electrons or six-coordinate 18 electrons. Thereby, a stable and long-life polymer light emitting material can be obtained.

  Specific examples of the metal complex represented by the above formula (1) include complexes represented by the following formulas (A) to (O), but are not limited to these complexes. Here, Y represents a polymerizable substituent having a polymerizable functional group, Ph represents a phenyl group, and Me represents a methyl group.

Among these, the complex represented by the above formulas (A), (B), and (O) is preferable because long lifetime is obtained with high luminous efficiency.
The metal complex represented by the above formula (1) can be produced 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 transport polymerizable compound and an electron transport polymerizable compound together with one or more monomers of the metal complex. 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 two or more hole transport polymerizable compounds together with a structural unit derived from one or more metal 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 metal complex, so that high light emission efficiency is obtained.

  In addition, the polymer light-emitting material includes a structural unit derived from one or two or more hole transport polymerizable compounds together with a structural unit derived from one or more metal complexes. 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 can be 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 can further be simplified, the organic EL element which was 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 substituent, and known ones are used.
The polymerizable substituent is not particularly limited in addition to having a polymerizable functional group moiety. For example, the substituent which is the same as the substituent which P and Q may have, and has a polymerizable functional group moiety is exemplified.

  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.

When the polymerizable functional group is an alkenyl group, the polymerizable compound is represented by the formula (A1) to
It preferably has a polymerizable substituent represented by (A12).
As the hole transport polymerizable compound, specifically, compounds represented by the following formulas (E1) to (E6) are preferable, and since the carrier mobility in the copolymer is high, the following formula (E1) to The compound represented by (E3) is more preferable.

  Specifically, the electron transporting polymerizable compound is preferably an electron transporting compound represented by the following formulas (E7) to (E14), and has a high carrier mobility in the copolymer. The compounds represented by E7) and (E12) to (E14) are more preferable.

  In the carrier transportable polymerizable compounds represented by the above formulas (E1) to (E14), the substituent represented by the above formula (A1) is represented by the above formulas (A2) to (A12). A compound substituted for a substituent is also preferably used, but a compound having a substituent represented by the above formulas (A1) and (A5) is particularly preferred because a polymerizable substituent can be easily introduced into the polymerizable compound.

  Among these, the copolymer is derived from the compound represented by any one of the above formulas (E1) to (E3) as the structural unit derived from the metal complex and the hole transport polymerizable compound. It is particularly preferable to have the structural unit to be used and the structural unit derived from the compound represented by any of the above formulas (E7) and (E12) to (E14) as the electron transporting polymerizable compound. A polymer light emitting material made of such a copolymer is desirable because of its high durability and high luminous efficiency. In this case, the use of the complex represented by the above formula (A) or (O) as the metal complex provides a long-life polymer light-emitting material with high luminance and higher luminous efficiency. preferable.

The carrier transportable polymerizable compounds represented by the above formulas (E1) to (E14) can be produced by a known method.
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 metal complex is x, 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 y (x and y are integers of 1 or more), the ratio of the number of structural units derived from the metal complex to the total number of structural units, that is, the value of x / (x + y) 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 x / (x + y) is within this range, an organic EL device having high luminous efficiency and 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. 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 metal 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) a single layer of the light emitting material 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. The light emitting layer in the organic EL device according to the present invention also includes other hole transport materials and / or electron transport materials in addition to the polymer light emitting material according to the present invention for the purpose of supplementing the carrier transport property of the light emitting layer. You may go out. 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); polyvinyl carbazole; a polymer compound obtained by polymerizing the triphenylamine derivative by introducing a polymerizable substituent; 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.

  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 used, so that the manufacturing process can be simplified.

  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). 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 can be used. 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. As a film forming method of the cathode material, for example, a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, or the like 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.

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>
A polymer light emitting material according to the present invention and an organic EL device using the polymer light emitting material are a display element, a display, a backlight, an electrophotography, an illumination light source, a recording light source, an exposure light source, a reading light source, a sign, a signboard, It is suitably used for interior and optical communication.

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 (1-1)

(1) Synthesis of diphenyl (4-vinylphenyl) phosphine 20 ml of dehydrated THF was added to 341 mg (14 mmol) of magnesium, and 10 ml of a THF solution of 2.70 g (15 mmol) of 4-bromostyrene was added dropwise to prepare a Grignard reagent. To the obtained solution, 10 ml of a THF solution of 2.50 g (11 mmol) of chlorodiphenylphosphine was added dropwise and stirred at room temperature for 1.5 hours. After distilling off the solvent under reduced pressure, the residue was purified by silica gel column chromatography and recrystallized from a hexane solution to obtain 2.30 g (8.3 mmol) of diphenyl (4-vinylphenyl) phosphine.
(2) Synthesis of iridium complex (1-1) 10 ml of 1,2-dichloroethane was added to a mixture of 0.20 g (0.29 mmol) of bis (cyclooctadiene) dichlorodiiridium and 0.090 g (0.59 mmol) of biphenylene. In addition, the mixture was heated to reflux for 4 hours. To the obtained reaction mixture, 0.10 g (0.38 mmol) of triphenylphosphine and 2.30 g (8.3 mmol) of diphenyl (4-vinylphenyl) phosphine were added and heated to reflux for 10 minutes. Subsequently, after distilling off the solvent under reduced pressure, 0.05 g (0.07 mmol) of an iridium complex (1-1) was obtained by recrystallization from a dichloromethane-hexane mixed solution.
[Synthesis Example 2] Synthesis of iridium complex (1-2)

(1) Synthesis of 6- (4-vinylphenyl) -2,4-hexanedione 1.23 g (60% in oil) (31 mmol) of sodium hydride was weighed under a nitrogen atmosphere, and 60 ml of dry tetrahydrofuran was added thereto. In addition, it was cooled to 0 ° C. with an ice bath. To this suspension, a mixed solution of 2.5 g (24 mmol) of acetylacetone and 1 ml of hexamethylphosphoric triamide was added dropwise to obtain a colorless precipitate. After stirring at 0 ° C. for 10 minutes, 17.5 ml (28 mmol) of n-butyllithium in hexane (1.6 M) was added dropwise to dissolve the precipitate, and the mixture was further stirred at 0 ° C. for 20 minutes. To the obtained pale yellow solution, 4.0 g (26 mmol) of 4-vinylbenzyl chloride was added dropwise, the reaction solution was returned to room temperature and stirred for 20 minutes, and diluted hydrochloric acid was added to acidify the aqueous layer. The organic layer was washed with a saturated aqueous sodium chloride solution and dried over magnesium sulfate, and then the solvent was distilled off with an evaporator. Purification by silica gel column chromatography gave 3.0 g (14 mmol) of 6- (4-vinylphenyl) -2,4-hexanedione.
(2) Synthesis of iridium complex (1-2) 10 ml of 1,2-dichloroethane was added to a mixture of 0.20 g (0.29 mmol) of bis (cyclooctadiene) dichlorodiiridium and 0.090 g (0.59 mmol) of biphenylene. In addition, the mixture was heated to reflux for 4 hours. To the obtained reaction mixture, 0.20 g (0.76 mmol) of triphenylphosphine was added and heated to reflux for 10 minutes. Next, after distilling off the solvent under reduced pressure, 0.10 g (0.94 mmol) of sodium carbonate, 0.20 g (0.92 mmol) of 6- (4-vinylphenyl) -2,4-hexanedione and 10 ml of THF were added. And heated to reflux for 2 hours. Subsequently, after distilling off the solvent under reduced pressure, purification by silica gel column chromatography (eluent: dichloromethane) gave 0.10 g (0.09 mmol) of an iridium complex (1-2).
Example 1 Synthesis of Copolymer (2-1) 80 mg of iridium complex (1-1), polymerizable compound (E2) 460 mg, and polymerizable compound (E7) 460 mg were placed in a sealed container, 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 acetone (500 ml) to obtain a precipitate. Further, reprecipitation purification with toluene-acetone was repeated twice, followed by vacuum drying at 50 ° C. overnight to obtain the desired copolymer (2-1).
[Example 2] Synthesis of copolymer (2-2) A copolymer (2-2) was prepared in the same manner as in Example 1 except that the iridium complex (1-2) was used instead of the iridium complex (1-1). 2-2) was obtained.
[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 the copolymer (2-1) 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, in an argon atmosphere, lead wires (wiring) were attached to the anode and the cathode, and four organic EL elements measuring 4 mm long × 3 mm wide 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 exhibited red light emission, the maximum light emission external quantum efficiency was 5.1%, and the maximum luminance was 300 cd / m ² .
[Example 4] Preparation of organic EL device and evaluation of EL emission characteristics Organic matter was obtained in the same manner as in Example 3 except that copolymer (2-2) was used instead of copolymer (2-1). An EL element was produced, and the emission color and emission luminance were measured. The produced organic EL device exhibited orange light emission, the maximum light emission external quantum efficiency was 5.6%, and the maximum luminance was 1050 cd / m ² .

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 (7)

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

(In the formula, M represents a metal atom having a coordination number n (n represents an integer of 4 to 6), and P and Q are each independently an aromatic group optionally having a substituent. It is a hydrocarbon group or an aromatic heterocyclic group which may have a substituent. P and Q constitute a bidentate ligand, and P and Q form a condensed ring. L ₁ is an i-dentate ligand having a polymerizable substituent (i represents a ligand conformation number and represents an integer of 1 to 4), and L ₂ is j is a ligand (where j represents the number of ligands and represents an integer of 1 to 3), X represents an anion or a counter ion of a cation, and a represents 1 or 2 represents an integer of 2, b represents an integer of 0 to 3, c represents an integer of 0 to 3, satisfies the relationship of n = 2 × a + i × 1 + j × b, and P, Q, L ₂ And X, when there are a plurality of each, May be the same or different.)   The polymer light-emitting material according to claim 1, wherein M is an iridium atom or a platinum atom. The M is a bidentate ligand composed of P and Q, L ₁ , and L _2, and adopts a bonding scheme by five-coordinate 16 electrons or six-coordinate 18 electrons. 3. The polymer light emitting material according to 1 or 2.   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 1 to 3.   In the organic electroluminescent element including one or two or more organic polymer layers sandwiched between an anode and a cathode, at least one layer of the organic polymer layer includes a high layer according to any one of claims 1 to 4. An organic electroluminescence device comprising a molecular light emitting material.   The image display apparatus using the organic electroluminescent element of Claim 5. A surface-emitting light source using the organic electroluminescence element according to claim 5.

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