JP2005139464A - Polymeric phosphor and organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymeric phosphor which has high fluorescence quantum yield, excellent solubility in solvents, and also excellent charge transferability. <P>SOLUTION: The polymeric phosphor, which is soluble into solvents and has fluorescence in a solid state, has a polystyrene-converted number-average molecular weight of 10<SP>3</SP>to 10<SP>7</SP>and consists of repeating units shown in Formula (1). Ar3 is a bifunctional group forming a C-C bond with adjoining two vinylene groups and is selected from an aromatic compound group consisting of 6-22C atoms taking part in forming conjugated bonds, or a heterocyclic compound group of a 5 or more-membered ring consisting of 4-20C containing a hetero atom, provided that the total number of carbon atoms and nitrogen atoms present in succession in the shortest course between the two carbon atoms bonded to the adjoining two vinylene groups is even in chemical structural formulas of these groups; and Ar4 is a bifunctional group forming a C-C bond with adjoining two vinylene groups and is selected from an aromatic compound group consisting of 6-22C atoms taking part in forming conjugated bonds, or a heterocyclic compound group of a 6 or more-membered ring consisting of 4-20C containing a hetero atom, provided that the total number of atoms present in succession in the shortest course between the two carbon atoms bonded to the adjoining two vinylene groups is 1, 3 or 5 in chemical structural formulas of these groups. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescence element (hereinafter, sometimes referred to as an organic EL element) prepared using a polymeric fluorescent substance and a polymeric fluorescent substance. Specifically, the present invention relates to an organic EL device having a high light emission efficiency and a solvent-soluble polymer phosphor having strong fluorescence, which is prepared using a solvent-soluble polymer phosphor having strong fluorescence.

An inorganic electroluminescence element (hereinafter, sometimes referred to as an inorganic EL element) using an inorganic phosphor as a light emitting material is used for display devices such as a planar light source or a flat panel display as a backlight. High voltage alternating current was necessary to make it.
In recent years, Tang et al. Fabricated an organic EL device having a two-layer structure in which an organic fluorescent dye is used as a light emitting layer and an organic charge transport compound used in an electrophotographic photoreceptor or the like is laminated. A high-efficiency, high-brightness organic EL element was realized (Japanese Patent Laid-Open No. 59-194393). Compared to inorganic EL elements, organic EL elements have the advantage of being able to easily emit light of a large number of colors in addition to low voltage drive and high brightness, so there are many element structures, organic fluorescent dyes, and organic charge transport compounds. An attempt has been reported [Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.), 27, L269 (1988)], [Journal of Applied Physics (J. Appl. Phys.) 65, 3610 (1989)].

Up to now, low molecular weight organic fluorescent dyes have been generally used as the material for the light emitting layer, and as high molecular weight light emitting materials, WO90113148, JP-A-3-244630, Applied Physics. -Letters (Appl. Phys. Lett.), 58, 1982 (1991). In the examples of the specification of WO90113148, a poly-p-phenylene vinylene thin film converted into a conjugated polymer was obtained by forming a soluble precursor on an electrode and performing a heat treatment, and this was used. An EL element is disclosed.
Japanese Patent Application Laid-Open No. 3-244630 exemplifies a conjugated polymer having a feature that itself is soluble in a solvent and does not require heat treatment. Applied Physics Letters (Appl. Phys. Lett.), 58, 1982 (1991) also describes a polymer light-emitting material soluble in a solvent and an organic EL device produced using the same. However, the organic EL device produced using these materials does not necessarily have a sufficiently high luminous efficiency.

An attempt to increase the quantum yield of fluorescence of a polymer light emitting material has already been reported [Nature 356, 47 (1992)]. In the process of generating a conjugated structure from a soluble intermediate copolymer by thermal decomposition, a polymer having a conjugated structure and a nonconjugated structure is obtained by leaving the nonconjugated structure, and exhibits strong fluorescence. Here, since 5-dimethoxy-p-phenylene-methoxy-ethylene is difficult to decompose only by heat treatment, it is used to suppress the entire copolymer from being converted to a conjugated polymer by heat treatment.
On the other hand, a polymer in which a conjugated low molecule having strong fluorescence and an aliphatic hydrocarbon are connected by an ether bond exhibits blue fluorescence due to its short conjugated chain length, and a blue light emitting organic EL device can be produced using this. [Macromolecules, Vol. 26, p. 1188 (1993)].
In addition, it has been reported that an alternating copolymer of unsubstituted p-phenylene vinylene and m-phenylene vinylene has green-blue fluorescence [Vysokomolecul. Soedin. 5, 805 (1963)] was not known about the quantum yield of fluorescence and EL characteristics.
From the viewpoint of the light emission efficiency of the organic EL device, a poly-p-phenylene vinylene derivative in which a cyano group is introduced into a vinylene group has a high electron affinity and facilitates electron injection. It has been reported that an EL device can be created, which shows a high value for the proportion of photons emitted per electron. [Nature (Vol. 365, p. 628) (1993)].

However, in organic EL devices using polymers reported so far, it is necessary to form a soluble intermediate into a thin film and then convert it into a conjugated polymer structure by high-temperature heat treatment. There were restrictions on the material of the substrate. In addition, when the precursor polymer is converted into a conjugated polymer by heat treatment, the abundance ratio of the non-conjugated portion in the polymer is controlled by the heat treatment conditions, etc. There was a risk of structural changes due to heat generation of the elements under driving.
In addition, when using a polymer in which a conjugated low molecule is linked to a non-conjugated aliphatic hydrocarbon with an ether bond, the conjugated chain length, which is thought to contribute to charge transport, is short, making it difficult to transfer charges. It is expected that.
A soluble conjugated polymer does not require a high-temperature heat treatment after forming a thin film, but the quantum yield of fluorescence and the light emission efficiency of the organic EL element are not sufficient, and materials with higher these are required.
Conventionally known poly-p-phenylene vinylene derivatives in which a cyano group is introduced into a vinylene group do not necessarily improve the quantum yield of fluorescence of the polymer itself.
Polymer phosphors with excellent solubility in solvents, high fluorescence quantum yields, and excellent electrical conductivity, and high-brightness organic EL elements that can be easily prepared by coating methods using polymer phosphors It was requested.

  The object of the present invention is to provide a polymer phosphor having a high fluorescence quantum yield, excellent solubility in a solvent, and excellent charge transportability, and a high brightness that can be easily produced by a coating method using the polymer phosphor. An object of the present invention is to provide an organic EL element with high luminous efficiency.

  In view of such circumstances, the present inventors have conducted intensive studies in order to improve the light emission efficiency of an organic EL device using a polymer phosphor as a light emitting layer. As a result, a conjugated bond is formed as a main chain as a polymer phosphor. The organic EL element can be easily produced by a coating method by using a polymer phosphor containing a repeating unit having a specific structure, and the organic EL element exhibits high luminous efficiency and has a main chain. The present inventors have found that a polymer fluorescent substance having a conjugated bond and a repeating unit having a specific structure exhibits a high quantum yield of fluorescence.

〔ただし、Ａｒ₁は、隣接する基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基、ヘテロ原子を含有する炭素数４個以上２０個以下からなる六員環以上の複素環化合物基、または該芳香族化合物基もしくは複素環化合物基とビニレン基が結合した基から選ばれ、これらの基の化学構造式において隣接する２つの基と結合した２つの炭素原子の間で最短の経路に連続して存在する原子の個数が１、３または５のいずれかであるものを示す。〕

〔ただし、Ａｒ₂は、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基、ヘテロ原子を含有する炭素数４個以上２０個以下からなる五員環以上の複素環化合物基、または該芳香族化合物基もしくは複素環化合物基とビニレン基が結合した基から選ばれ、これらの基の化学構造式において隣接する２つの基と結合した２つの炭素原子の間で最短の経路に連続して存在する炭素原子および窒素原子の個数の合計が偶数であるものを示す。〕
で表わされる繰り返し単位をそれぞれ１種類以上含み、化１で示される繰り返し単位が、繰り返し単位数で全体の２〜５０％含まれ、かつ固体状態で蛍光を有し、溶媒可溶性である高分子蛍光体を含むことを特徴とする有機エレクトロルミネッセンス素子。 That is, the present invention is the invention described below.
(1) In an organic electroluminescence device having at least a light emitting layer between electrodes composed of a pair of an anode and a cathode, at least one of which is transparent or translucent, the light emitting layer has the following chemical formula 1 and chemical formula 2,

[However, Ar ₁ is a bifunctional group that forms a carbon-carbon bond with an adjacent group, and an aromatic compound group or hetero atom having 6 to 22 carbon atoms involved in the conjugated bond. The chemical structure of these groups is selected from the group consisting of a heterocyclic compound group having 6 to 20 carbon atoms and a heterocyclic compound group having 6 or more carbon atoms, or a group in which the aromatic compound group or heterocyclic compound group and vinylene group are bonded. In the formula, the number of atoms present in succession in the shortest path between two carbon atoms bonded to two adjacent groups is either 1, 3 or 5. ]

[However, Ar ₂ is an aromatic compound group having 6 to 22 carbon atoms involved in a conjugated bond, or a heterocycle having a 5-membered ring or more containing 4 to 20 carbon atoms containing a hetero atom. A ring compound group, or a group in which the aromatic compound group or heterocyclic compound group and a vinylene group are bonded, and the shortest of two carbon atoms bonded to two adjacent groups in the chemical structural formula of these groups In which the total number of carbon atoms and nitrogen atoms continuously present in the path is an even number. ]
Polymer fluorescence containing at least one type of repeating unit represented by formula (1), wherein the repeating unit represented by Chemical Formula 1 is 2 to 50% of the total number of repeating units, has fluorescence in a solid state, and is soluble in a solvent. An organic electroluminescence device comprising a body.

〔ただし、Ａｒ₃は、隣接する２つのビニレン基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基またはヘテロ原子を含有する炭素数４個以上２０個以下からなる五員環以上の複素環化合物基から選ばれ、これらの基の化学構造式において隣接する２つのビニレン基と結合した２つの炭素原子の間で最短の経路に連続して存在する炭素原子および窒素原子の個数の合計が偶数であるものを示す。Ａｒ₄は、隣接した２つのビニレン基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基またはヘテロ原子を含有する炭素数４個以上２０個以下からなる六員環以上の複素環化合物基から選ばれ、これらの基の化学構造式において隣接する２つのビニレン基と結合した２つの炭素原子の間で最短の経路に連続して存在する原子の個数が１、３または５のいずれかであるものを示す。〕
で示される繰り返し単位からなることを特徴とする高分子蛍光体。 (2) Soluble in a solvent, having fluorescence in a solid state, having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₃ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond, or Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. Ar ₄ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and represents an aromatic compound group or hetero atom having 6 to 22 carbon atoms involved in the conjugated bond. The shortest of two carbon atoms bonded to two adjacent vinylene groups in the chemical structure of these groups, which is selected from 6 to 20-membered heterocyclic compound groups having 4 to 20 carbon atoms In which the number of atoms continuously present in the route is 1, 3 or 5. ]
A polymeric fluorescent substance comprising a repeating unit represented by:

〔ただし、Ａｒ₅は、隣接する２つのビニレン基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基またはヘテロ原子を含有する炭素数４個以上２０個以下からなる五員環以上の複素環化合物基から選ばれ、これらの基の化学構造式において隣接する２つのビニレン基と結合した２つの炭素原子の間で最短の経路に連続して存在する炭素原子および窒素原子の個数の合計が偶数であるものを示す。Ａｒ₆は、隣接する２つのビニレン基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基またはヘテロ原子を含有する炭素数４個以上２０個以下からなる六員環以上の複素環化合物基から選ばれ、これらの基の化学構造式において隣接する２つのビニレン基と結合した２つの炭素原子の間に連続して存在する原子の個数が１、３または５のいずれかであるものを示す。〕
で示される繰り返し単位からなることを特徴とする高分子蛍光体。 (3) Soluble in a solvent, having fluorescence in a solid state, having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₅ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond, or Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. Ar ₆ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and represents an aromatic compound group or hetero atom having 6 to 22 carbon atoms involved in the conjugated bond. Contained between two carbon atoms bonded to two adjacent vinylene groups in the chemical structure of these groups, which are selected from a heterocyclic compound group having 6 to 20 carbon atoms and having 6 or more carbon atoms. And the number of atoms present is one of 1, 3 or 5. ]
A polymeric fluorescent substance comprising a repeating unit represented by:

〔ただし、Ａｒ₇は、隣接する２つのビニレン基と炭素−炭素結合を形成する二官能の基であり、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基またはヘテロ原子を含有する炭素数４個以上２０個以下からなる五員環以上の複素環化合物基から選ばれ、これらの基の化学構造式において隣接する２つのビニレン基と結合した２つの炭素原子の間で最短の経路に連続して存在する炭素原子および窒素原子の個数の合計が偶数であるものを示す。〕
で示される繰り返し単位からなる共重合体で、化３の繰り返し単位が全繰り返し単位の５モル％以上含まれることを特徴とする高分子蛍光体。 (4) Soluble in a solvent, having fluorescence in a solid state, having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₇ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group composed of 6 to 22 carbon atoms involved in the conjugated bond; Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. ]
A polymer phosphor comprising a repeating unit represented by the formula (1), wherein the repeating unit of Chemical Formula 3 is contained in an amount of 5 mol% or more of all repeating units.

(5) A copolymer that is soluble in a solvent, has fluorescence in a solid state, has a polystyrene-equivalent number average molecular weight of 10 ³ to 10 7, and is composed of repeating units represented by Chemical Formula 4 and Chemical Formula 5 above. A polymeric fluorescent substance, wherein the repeating unit of Chemical Formula 4 is contained in an amount of 5 mol% or more of all repeating units.

〔ここでＲ₁〜Ｒ₃₃は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基およびアルキルチオ基；炭素数６〜１８のアリール基およびアリールオキシ基；ならびに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。〕
に示す構造の少なくとも１つを含む繰り返し単位から選ばれることを特徴とする（１）記載の有機エレクトロルミネッセンス素子。 (6) The repeating unit represented by Chemical Formula 1 is

[Wherein R _{1 to} R ₃₃ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; It is a group selected from the group consisting of 4 to 14 heterocyclic compound groups. ]
The organic electroluminescence device according to (1), which is selected from repeating units containing at least one of the structures shown in (1).

(7) The Ar 3 of Chemical Formula ₃ or the Ar _{6 of} Chemical Formula ₄ contained in the polymeric fluorescent substance is selected from repeating units containing the structure represented by Chemical Formula ₆ above (2), (3), ( The polymeric fluorescent substance as described in 4) or (5).

〔ここでＸは、Ｃ−Ｒ₄₅、Ｎから選ばれた基、Ｒ₃₄〜Ｒ₄₅は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基およびアルキルチオ基；炭素数６〜１８のアリール基およびアリールオキシ基；ならびに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。〕
で表わされる繰り返し単位からなる共重合体であることを特徴とする（１）または（６）記載の有機エレクトロルミネッセンス素子。 (8) The polymeric fluorescent substance is represented by the following chemical formula 7 and chemical formula 8,

[Wherein X is a group selected from C—R ₄₅ and N, R _{34 to} R ₄₅ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; carbon A group selected from the group consisting of an aryl group and an aryloxy group having 6 to 18 carbon atoms; and a heterocyclic compound group having 4 to 14 carbon atoms. ]
The organic electroluminescent device according to (1) or (6), wherein the organic electroluminescent device is a copolymer comprising a repeating unit represented by the formula:

化３のＡｒ₄または化４のＡｒ₆が下記化１０、

〔ここでＸは、Ｃ−Ｒ₅₃、Ｎから選ばれた基、Ｒ₄₆〜Ｒ₅₃は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基およびアルキルチオ基；炭素数６〜１８のアリール基およびアリールオキシ基；ならびに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。〕
で表わされる繰り返し単位からなる共重合体であることを特徴とする（２）、（３）、（４）、（５）または（７）記載の高分子蛍光体。 (9) Ar ₃ of Chemical Formula ₃ , Ar _{5 of} Chemical Formula 4 or Ar _{7 of} Chemical Formula ₅ included in the polymeric fluorescent substance is

Ar _{4 in} Chemical Formula ₃ or Ar _{6 in} Chemical Formula ₄ is

[Wherein X is a group selected from C—R ₅₃ and N, R _{46 to} R ₅₃ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; carbon A group selected from the group consisting of an aryl group and an aryloxy group having 6 to 18 carbon atoms; and a heterocyclic compound group having 4 to 14 carbon atoms. ]
The polymeric fluorescent substance according to (2), (3), (4), (5) or (7), which is a copolymer comprising a repeating unit represented by the formula:

(10) The organic electroluminescence according to (1), (6) or (8), wherein a layer made of an electron transporting compound is provided adjacent to the light emitting layer between the cathode and the light emitting layer. element.
(11) The organic electro of (1), (6) or (8), wherein a layer made of a hole transporting compound is provided adjacent to the light emitting layer between the anode and the light emitting layer. Luminescence element.

(12) Between the cathode and the light emitting layer, adjacent to the light emitting layer, from the electron transporting compound, and between the anode and the light emitting layer, adjacent to the light emitting layer, from the hole transporting compound. The organic electroluminescent element according to (1), (6) or (8), wherein a layer is provided.
(13) In an organic electroluminescence device having at least a light emitting layer between a pair of anodes and cathodes, at least one of which is transparent or translucent, the light emitting layer is (2), (3), (4), (5) The organic electroluminescent element characterized by including the polymeric fluorescent substance as described in (7) or (9).

(14) The light emitting layer comprises the polymeric fluorescent substance according to (2), (3), (4), (5), (7) or (9), and the cathode and the light emitting layer, The organic electroluminescent device according to (13), wherein a layer made of an electron transporting compound is provided adjacent to the light emitting layer.
(15) The light-emitting layer includes the polymeric fluorescent substance according to (2), (3), (4), (5), (7) or (9), and the anode and the light-emitting layer, The organic electroluminescent device according to (13), wherein a layer made of a hole transporting compound is provided adjacent to the light emitting layer.

(16) The light-emitting layer contains the polymeric fluorescent substance according to (2), (3), (4), (5), (7) or (9), and the cathode and the light-emitting layer, A layer made of an electron transporting compound adjacent to the light emitting layer and a layer made of a hole transporting compound adjacent to the light emitting layer are provided between the anode and the light emitting layer (13). ) Organic electroluminescent device according to the above.

The organic EL device using the polymeric fluorescent substance of the present invention can be preferably used as an apparatus such as a planar light source as a backlight or a flat panel display because it is easy to produce and exhibits excellent light emission characteristics. The polymeric fluorescent substance of the present invention has strong fluorescence and is soluble in an organic solvent, and can be used as a light emitting material for an organic EL element, a dye for a dye laser, and the like.

  Hereinafter, the polymeric fluorescent substance used in the polymeric fluorescent substance and organic EL element of the present invention will be described in detail.

The polymeric fluorescent substance is a copolymer containing at least one type of repeating unit represented by Chemical Formula 1 or Chemical Formula 2 and 2 to 50% of the repeating unit represented by Chemical Formula 1 in terms of the number of repeating units. Although it depends on the structure of the repeating unit, the repeating unit represented by Chemical Formula 1 is more preferably 5 to 30% in terms of the number of repeating units.

（Ｒ₅₄ 、Ｒ₅₅は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基およびアルキルチオ基；炭素数６〜１８のアリール基およびアリールオキシ基；ならびに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。）
これらのなかで１，３−フェニレン基、ナフタレン−１，３−ジイル基、ピリジン−２，６−ジイル基、キノリン−２，４−ジイル基、ならびにそれらがビニレン基と結合したアリーレンビニレン基、およびそれらに置換基のついた基が好ましい。
さらに好ましくは、１，３−フェニレン基、ピリジン−２，６−ジイル基、ならびにそれらがビニレン基と結合したアリーレンビニレン基、およびそれらに置換基のついた基である。 In the polymeric fluorescent substance, Ar ₁ in Chemical Formula ₁ is a bifunctional group that forms a carbon-carbon bond with an adjacent group, and is an fragrance having 6 to 22 carbon atoms involved in the conjugated bond. Selected from the group consisting of an aromatic compound group, a heterocyclic compound group having 6 to 20 carbon atoms containing a heteroatom and having 6 or more carbon atoms, or a group in which the aromatic compound group or heterocyclic compound group and vinylene group are bonded. In the chemical structural formula, the number of atoms continuously present in the shortest path between two carbon atoms bonded to two adjacent groups is either 1, 3 or 5.
Specific examples include a divalent aromatic compound group represented by Chemical Formula 6 or a derivative group thereof, and an arylene vinylene group in which these groups are bonded to a vinylene group or a substituted vinylene group represented by Chemical Formula 11 below.

( _R54 and _R55 are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; and And a group selected from the group consisting of 14 heterocyclic compound groups.)
Among these, 1,3-phenylene group, naphthalene-1,3-diyl group, pyridine-2,6-diyl group, quinoline-2,4-diyl group, and arylene vinylene group in which they are bonded to vinylene group, And groups with substituents on them are preferred.
More preferred are a 1,3-phenylene group, a pyridine-2,6-diyl group, an arylene vinylene group in which they are bonded to a vinylene group, and a group having a substituent on them.

Ar ₂ in Chemical Formula ₂ includes an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond, and a 5-membered ring having 4 to 20 carbon atoms containing a hetero atom. It is selected from the above heterocyclic compound group, or a group in which the aromatic compound group or heterocyclic compound group and vinylene group are bonded, and the shortest of two carbon atoms bonded to two adjacent groups in the chemical structural formula The sum of the number of carbon atoms and nitrogen atoms present continuously in the path is an even number.
Specific examples include a divalent aromatic compound group represented by the following chemical formula 12 or a derivative group thereof, and an arylene vinylene group in which these groups and a vinylene group or a substituted vinylene group represented by chemical formula 11 are bonded.

（Ｒ₅₆ 〜Ｒ₉₀は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基およびアルキルチオ基；炭素数６〜１８のアリール基およびアリールオキシ基；ならびに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。）

(R _{56 to} R ₉₀ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; and And a group selected from the group consisting of 14 heterocyclic compound groups.)

Among these, 1,4-phenylene group, naphthalene-2,6-diyl group, anthracene-9,10-diyl group, pyridine-2,5-diyl group, 2,5-thienylene group, and these are vinylene groups Are preferably arylene vinylene groups bonded to and groups having substituents thereon.
More preferably, it is a 1,4-phenylene group, a pyridine-2,5-diyl group, a 2,5-thienylene group, an arylene vinylene group in which they are bonded to a vinylene group, and a group having a substituent on them. .
In addition, it becomes a larger repeating unit by combining said repeating unit. For example, when a 1,4-phenylene group and a 1,4-phenylene vinylene group are combined, a 4,4′-biphenylene vinylene group is obtained.

Here, the substituent is described. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group. A methyl group, an ethyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and lauryloxy group. A methoxy group, an ethoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group are preferable.
Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, a laurylthio group, and the like. A methylthio group, an ethylthio group, a pentylthio group, a hexylthio group , A heptylthio group and an octylthio group are preferable.
Examples of the aryl group include a phenyl group, a 4-C1-C12 alkoxyphenyl group (C1-C12 represents 1 to 12 carbon atoms), a 4-C1-C12 alkylphenyl group, a 1-naphthyl group, 2- Examples thereof include a naphthyl group.
A phenoxy group is illustrated as an aryloxy group.
Examples of the heterocyclic compound group include a 2-thienyl group, 2-pyrrolyl group, 2-furyl group, 2-, 3- or 4-pyridyl group.

The polymeric fluorescent substance used in the organic EL device of the present invention contains 2 to 50% of repeating units represented by Chemical Formula 1 in terms of the number of repeating units. In the polymeric fluorescent substance, the substantial conjugated chain length becomes an appropriate size, and the quantum yield of fluorescence increases. More preferably, the repeating unit represented by Chemical Formula 1 includes 5 to 30% of the total number of repeating units.

Next, the polymeric fluorescent substance of the present invention will be described.
The polymeric fluorescent substance of the present invention is a polymer soluble in a solvent, and the polymer has a number average molecular weight of 10 ³ to 10 ⁷ , and the polymer is a repeating unit represented by the chemical formula ^{3 or a} chemical formula A polymeric fluorescent substance characterized by comprising a repeating unit represented by formula 4, a copolymer of a repeating unit represented by formula 3 and a repeating unit represented by formula 5 wherein the repeating unit represented by formula 3 is all repeating units Or a copolymer of a repeating unit represented by Chemical Formula 4 and a repeating unit represented by Chemical Formula 5 wherein all the repeating units represented by Chemical Formula 4 are all repeating units. It is contained in 5 mol% or more of the polymeric fluorescent substance characterized by the above-mentioned. Here, the number average molecular weight is a polystyrene-equivalent number average molecular weight determined by gel permeation chromatography (GPC) using chloroform as a solvent.

Although it depends on the structure of the repeating unit, the repeating unit represented by Chemical Formula 3 or Chemical Formula 4 is more preferably 10 mol% or more of the total repeating units. From the viewpoint of solvent solubility, Ar ₃ and Ar ₄ of the repeating unit represented by Chemical Formula ₃ , Ar ₅ and Ar ₆ of the repeating unit represented by Chemical Formula ₄ , or Ar ₇ of the repeating unit represented by Chemical Formula ₅ One or more selected from one or more alkyl groups having 4 to 20 carbon atoms, alkoxy groups and alkylthio groups, aryl groups having 6 to 18 carbon atoms and aryloxy groups, and heterocyclic compound groups having 4 to 14 carbon atoms. It preferably has a group.

Examples of these substituents are as follows. Examples of the alkyl group having 4 to 20 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group, and a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 4 to 20 carbon atoms include a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, and the like, such as a pentyloxy group and a hexyloxy group. , A heptyloxy group and an octyloxy group are preferable.
Examples of the alkylthio group include a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decyloxy group, and a laurylthio group, and a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group are preferable.
As the aryl group, a phenyl group, a 4-C ₁ -C ₁₂ alkoxyphenyl group (C ₁ -C ₁₂ represents any one of 1 to 12 carbon atoms), 4-C ₁ -C ₁₂ alkyl Examples include a phenyl group, 1-naphthyl group, 2-naphthyl group and the like.
A phenoxy group is illustrated as an aryloxy group. Examples of the heterocyclic compound group include a 2-thienyl group, 2-pyrrolyl group, 2-furyl group, 2-, 3- or 4-pyridyl group.

  From the viewpoint of obtaining a polymeric fluorescent substance having a high fluorescence quantum yield, the polymeric fluorescent substance of the present invention needs to contain the repeating unit represented by Chemical Formula 3 or Chemical Formula 4 above. Further, the fluorescence peak corresponding to the ratio of the repeating unit represented by the chemical formula 3 and the repeating unit represented by the chemical formula 5 or the ratio of the repeating unit represented by the chemical formula 4 and the repeating unit represented by the chemical formula 5 is shown. Since the wavelength also changes, it is advantageous in that the fluorescent color can be selected.

The polymeric fluorescent substance used in the polymeric fluorescent substance of the present invention and the organic EL element of the present invention may be a random, block or graft copolymer, or a polymer having an intermediate structure thereof, For example, it may be a random copolymer having block properties. From the viewpoint of obtaining a copolymer having a high fluorescence quantum yield, a random copolymer having a block property and a block or graft copolymer are preferable to a complete random copolymer.
In addition, since the organic EL element of the present invention utilizes light emission from a thin film, the polymer fluorescent substance having fluorescence in a solid state is used.

  The polymeric fluorescent substance of the present invention and the polymeric fluorescent substance used in the organic EL device of the present invention have a bent portion in the main chain, so that it is basically not difficult to form a film by dissolving in a solvent. In order to obtain a polymer having better solubility and good film forming properties, at least one alkyl group, alkoxy group or alkylthio group having 4 to 20 carbon atoms per conjugated moiety; 6 to 18 carbon atoms It is more preferable that the aryl group or aryloxy group of the above-mentioned aryl group or aryloxy group; or an aryl group or heterocyclic compound group substituted with one or more nucleus by using a heterocyclic compound group having 4 to 14 carbon atoms as a substituent.

Examples of these substituents are as follows. Examples of the alkyl group having 4 to 20 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group, and a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 4 to 20 carbon atoms include a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, and the like, such as a pentyloxy group and a hexyloxy group. , A heptyloxy group and an octyloxy group are preferable.
Examples of the alkylthio group include a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decyloxy group, and a laurylthio group, and a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group are preferable.
Examples of the aryl group include a phenyl group, 4-C ₁ ~C ₁₂ alkoxyphenyl group (C ₁ -C ₁₂ indicates that the number of one of 1 to 12 carbon.), 4-C ₁ ~C Examples thereof include a ₁₂ alkylphenyl group, a 1-naphthyl group, and a 2-naphthyl group.
A phenoxy group is illustrated as an aryloxy group. Examples of the heterocyclic compound group include a 2-thienyl group, 2-pyrrolyl group, 2-furyl group, 2-, 3- or 4-pyridyl group.

The number of these substituents varies depending on the molecular weight of the polymer and the constitution of the repeating unit, but from the viewpoint of obtaining a highly soluble copolymer, it is more preferable that these substituents are at least one per 600 molecular weight. .
Examples of the good solvent for the polymeric fluorescent substance include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like. Although depending on the structure and molecular weight of the polymeric fluorescent substance, it can usually be dissolved in these solvents in an amount of 0.1 wt% or more.

The polymerization degree of the polymeric fluorescent substance used in the polymeric fluorescent substance of the present invention and the organic EL element of the present invention is not particularly limited as long as the molecular weight is 10 ³ to 10 ⁷ in terms of polystyrene. change. In general, the total number of repeating structures is preferably 4 to 10000, more preferably 5 to 3000, and particularly preferably 10 to 2000 from the viewpoint of film formability.

  When forming a film from a solution by using these organic solvent-soluble polymeric fluorescent substances when preparing an organic EL device, it is only necessary to remove the solvent by drying after applying this solution. The same technique can be applied even when the materials are mixed, which is very advantageous in manufacturing.

The method for synthesizing the polymeric fluorescent substance used in the organic EL device of the present invention is not particularly limited. For example, a dialdehyde compound in which two aldehyde groups are bonded to a repeating unit represented by Chemical Formula 1 and a repeating method represented by Chemical Formula 2 A Wittig reaction from a diphosphonium salt obtained from a compound having two halogenated methyl groups bonded to a unit and triphenylphosphine is exemplified.
Here, the dialdehyde compound and the diphosphonium salt can be bonded adjacent to each other, but the compounds having the same structure are not bonded adjacent to each other. Therefore, the substantial conjugated chain length of the resulting polymeric fluorescent substance can be freely adjusted by adding a dialdehyde compound in which two aldehyde groups are bonded to the repeating unit represented by Chemical Formula 2 and changing the proportion of the compound. .
As another synthesis method, a compound in which a methyl halide group is bonded to both ends of an aromatic oligomer containing a repeating unit represented by Chemical Formula 1 and two methyl halide groups are bonded to a repeating unit represented by Chemical Formula 2 Examples are dehydrohalogenation methods from compounds.
Furthermore, a sulfonium salt decomposition method for obtaining the polymeric fluorescent substance by heat treatment from an intermediate obtained by polymerizing a compound in which both ends of the aromatic oligomer containing a repeating unit represented by Chemical Formula 1 are sulfonium salts with an alkali is exemplified. .
Among these, the method by Wittig reaction is preferable in terms of reaction control and yield.

Further, the method for synthesizing the polymeric fluorescent substance of the present invention is not particularly limited. For example, Journal of Organic Chemistry (J. Org. Chem.) Vol. 25, page 813 (1959), Macromolecular A copolymer can be obtained using a method similar to the method described in Chemi (Makromol. Chem.), Vol. 74, p. 71 (1964).
That is, for example, a corresponding diacetonitrile compound, more specifically, for example, m-phenylene diacetonitrile and a corresponding dialdehyde compound, more specifically, for example, 2,5-dioctyloxyterephthalaldehyde, for example, ethyl A Knoevenagel reaction in which polymerization is performed using sodium methoxide in an alcohol / chloroform mixed solvent can be given. In order to obtain a copolymer, two or more kinds of diacetonitrile and / or two or more kinds of dialdehyde compounds may be reacted.
Furthermore, both the Wittig reaction and the Knoevenagel reaction can be carried out using lithium ethoxide or the like, so that all of these can be carried out by mixing and reacting dialdehyde compounds, diphosphonium salt compounds and diacetonitrile compounds. The copolymer is obtained.

More specifically, a method for synthesizing an arylene vinylene copolymer, which is one example of the polymeric fluorescent substance used in the organic EL device of the present invention, will be described.
For example, when an arylene vinylene copolymer is obtained by Wittig reaction, for example, first, a bis (methyl halide) compound, more specifically, for example, 2,5-dioctyloxy-p-xylylene dibromide is converted to N, A phosphonium salt is synthesized by reacting with triphenylphosphine in an N-dimethylformamide solvent, and this is combined with a dialdehyde compound containing the structure of Chemical Formula 1, more specifically, for example, isophthalaldehyde, for example, in ethyl alcohol. An arylene vinylene copolymer containing a 1,3-phenylene group is obtained by a Wittig reaction in which lithium ethoxide is condensed. At this time, if a dialdehyde compound containing the structure of Chemical Formula 2, specifically terephthalaldehyde, is added, a copolymer having a longer conjugated chain length can be obtained. In order to obtain a copolymer, two or more kinds of diphosphonium salts and / or two or more kinds of dialdehyde compounds may be reacted.
In addition, when these polymers are used as a light emitting material of an organic EL device, the purity affects the light emission characteristics, and therefore it is desirable to perform purification treatment such as reprecipitation purification and fractionation by chromatography.

Regarding the structure of the organic EL device produced using the luminescent material of the present invention, the luminescent material made of the aforementioned polymer is used in the luminescent layer provided between a pair of electrodes, at least one of which is transparent or translucent. If there is no particular limitation, a known structure is adopted.
For example, a pair of electrodes on both sides of a light emitting layer made of the polymer fluorescent material or a light emitting layer made of a mixture of the polymer fluorescent material and a charge transport material (meaning a generic name of an electron transport material and a hole transport material) And an electron transport layer containing an electron transport material between the light emitting layer and the cathode and / or a layer in which a hole transport layer containing a hole transport material is laminated between the light emitting layer and the anode. The
Further, the present invention includes a case where the light emitting layer and the charge transport layer are a single layer and a combination of a plurality of layers. Furthermore, for example, a light emitting material other than the polymeric fluorescent substance described below may be mixed and used in the light emitting layer. Moreover, it can also be set as the layer which disperse | distributed this polymeric fluorescent substance and / or charge transport material to the high molecular compound.

  A charge transport material used together with the polymer of the present invention, that is, an electron transport material or a hole transport material can be a known material, and is not particularly limited, but examples of the hole transport material include pyrazoline derivatives, arylamine derivatives, Stilbene derivatives, triphenyldiamine derivatives, and the like include oxadiazole derivatives, anthraquinodimethane and derivatives thereof, benzoquinone and derivatives thereof, naphthoquinone and derivatives thereof, anthraquinones and derivatives thereof, tetracyanoanthraquinodimethane and Examples thereof include fluorenone derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, and metal complexes of 8-hydroxyquinoline and derivatives thereof.

Specifically, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-209998, JP-A-3-37992, and JP-A-3-152184. The thing etc. which are described in the gazette are illustrated. The hole transport material is preferably a triphenyldiamine derivative, the electron transport material is preferably an oxadiazole derivative, benzoquinone and its derivative, anthraquinone and its derivative, 8-hydroxyquinoline and its metal complex, and in particular, a hole transport material. 4,4′-bis (N (3-methylphenyl) -N-phenylamino) biphenyl as the electron transport material, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1, 3,4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are preferred.
Of these, one or both of an electron transporting compound and a hole transporting compound may be used simultaneously. These may be used singly or in combination of two or more.

When a charge transport layer is provided between the light-emitting layer and the electrode, the charge transport layer may be formed using these charge transport materials.
In addition, when the charge transport material is mixed with the light emitting layer, the amount of the charge transport material varies depending on the type of the compound used, etc. It may be determined as appropriate in consideration. Usually, it is 1 to 40 weight% with respect to a luminescent material, More preferably, it is 2 to 30 weight%.

  Although it does not specifically limit as a known luminescent material which can be used with the polymeric fluorescent substance of this invention, For example, pigment | dyes, such as a naphthalene derivative, anthracene and its derivative (s), perylene and its derivative (s), a polymethine type, a xanthene type, a coumarin type, a cyanine type , Metal complexes of 8-hydroxyquinoline and its derivatives, aromatic amines, tetraphenylcyclopentadiene and its derivatives, tetraphenylbutadiene and its derivatives, and the like can be used. Specifically, for example, known ones such as those described in JP-A-57-51781 and 59-194393 can be used.

Next, a typical method for manufacturing an organic EL element using the light emitting material of the present invention will be described. As a pair of electrodes composed of an anode and a cathode, a transparent or translucent electrode is formed by forming a transparent or translucent electrode on a transparent substrate such as glass or transparent plastic.
As the material for the anode, a conductive metal oxide film, a translucent metal thin film, or the like is used. Specifically, a film (NESA etc.) made of conductive glass made of indium tin oxide (ITO), tin oxide or the like, Au, Pt, Ag, Cu or the like is used. As a manufacturing method, a vacuum deposition method, a sputtering method, a plating method, or the like is used.

  Next, a light emitting layer containing the polymer or the polymer and a charge transport material as the light emitting material is formed on the anode. Examples of the forming method include spin coating methods, casting methods, dipping methods, bar coating methods, roll coating methods and the like using melts, solutions or mixed solutions of these materials. It is particularly preferable to form a film by a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method, or a roll coating method.

The thickness of the light emitting layer is 0.5 nm to 10 μm, preferably 1 nm to 1 μm. In order to increase the current density and increase the light emission efficiency, the range of 10 to 500 nm is preferable.
In addition, when it thins by the apply | coating method, in order to remove a solvent, it is desirable to heat-dry at the temperature of 30-300 degreeC under reduced pressure or inert atmosphere, Preferably it is 60-200 degreeC.

  In addition, when the light emitting layer and the charge transport layer (which means a generic name of a hole transport layer and an electron transport layer) are laminated, the positive electrode is formed on the anode before the light emitting layer is provided by the above-described film forming method. It is preferable to form the hole transport layer and / or form the electron transport layer thereon after providing the light emitting layer.

The method for forming the charge transport layer is not particularly limited, but it can be applied by vacuum deposition from a powder state, or spin coating after being dissolved in a solution, casting, dipping, bar coating, roll coating, etc. Or a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method, a roll coating method after the polymer compound and the charge transport material are mixed and dispersed in a solution state or a molten state. it can. The polymer compound to be mixed is not particularly limited, but those that do not extremely inhibit charge transport are preferable, and those that do not strongly absorb visible light are preferably used.
Any charge transporting polymer compound can be used in the charge transport layer without being mixed with a low molecular charge transport material.

  Examples of the polymer compound include poly (N-vinylcarbazole), polyaniline and derivatives thereof, polythiophene and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, poly (2,5-thienylene vinylene) and derivatives thereof, Examples include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polysiloxane and the like. In view of easy film formation, it is preferable to use a coating method.

  The thickness of the charge transport layer needs to be at least such that no pinholes are generated. However, if the thickness is too large, the resistance of the device increases and a high driving voltage is required, which is not preferable. Therefore, the film thickness of the charge transport layer is 0.5 nm to 10 μm, preferably 1 nm to 1 μm, more preferably 5 to 200 nm.

  Next, an electrode is provided on the light emitting layer or the electron transport layer. This electrode becomes an electron injection cathode. The material is not particularly limited, but a material having a small ionization energy is preferable. For example, Al, In, Mg, Ca, Li, Mg—Ag alloy, In—Ag alloy, Mg—In alloy, Mg—Al alloy, Mg—Li alloy, Al—Li alloy, graphite thin film, and the like are used. As a method for producing the cathode, a vacuum deposition method, a sputtering method, or the like is used.

Action

  In the present invention, it is considered that the polymeric fluorescent substance is excellent as a luminescent material because it has a relatively high melting point and decomposition temperature, is thermally stable, and has a high quantum yield of fluorescence. In addition, since a light emitting layer having excellent uniformity can be easily formed by a coating method, an organic EL device having high light emission efficiency can be manufactured very easily.

１０ ： ５０ ： ４０

該高分子蛍光体１のポリスチレン換算の数平均分子量は、９．８×１０³であった。該高分子蛍光体１の構造については赤外吸収スペクトル、ＮＭＲで確認した。 Examples of the present invention are shown below, but the present invention is not limited to these.
Here, for the number average molecular weight, the number average molecular weight in terms of polystyrene was determined by gel permeation chromatography (GPC) using chloroform as a solvent.
Example 1
<Synthesis of polymeric fluorescent substance 1>
2,5-Dioctyloxy-p-xylylene dibromide was reacted with triphenylphosphine in N, N-dimethylformamide solvent to synthesize phosphonium salts. 9.56 parts by weight of the obtained phosphonium salt, 0.268 parts by weight of isophthalaldehyde, and 1.07 parts by weight of terephthalaldehyde were dissolved in ethyl alcohol. An ethyl alcohol solution containing 1.56 parts by weight of lithium ethoxide was dropped into an ethyl alcohol solution of a phosphonium salt and a dialdehyde and polymerized at room temperature for 3 hours. After standing overnight at room temperature, the precipitate was filtered off, washed with ethyl alcohol, dissolved in chloroform, and ethanol was added thereto to form a precipitate again. This was dried under reduced pressure to obtain 3.64 parts by weight of a polymer. This is called polymeric fluorescent substance 1. The repeating unit of the polymeric fluorescent substance 1 calculated from the monomer charge ratio and the molar ratio thereof are shown below.

10:50:40

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 1 was 9.8 × 10 ³ . The structure of the polymeric fluorescent substance 1 was confirmed by infrared absorption spectrum and NMR.

<Measurement of absorption spectrum and fluorescence spectrum and evaluation of quantum yield of fluorescence>
The polymeric fluorescent substance 1 polymer could be easily dissolved in chloroform. A 0.05% chloroform solution was spin-coated on a quartz plate to form a polymer thin film. The ultraviolet-visible absorption spectrum and fluorescence spectrum of this thin film were measured using a self-recording spectrophotometer UV365 manufactured by Shimadzu Corporation and a fluorescence spectrophotometer 850 manufactured by Hitachi, Ltd., respectively. For the calculation of the quantum yield of fluorescence, the fluorescence spectrum when excited at 410 nm was used. The fluorescence intensity was obtained as a relative value by dividing the area of the fluorescence spectrum plotted with the wave number on the horizontal axis and the absorbance at 410 nm. As shown in Table 1, the fluorescence intensity of the polymeric fluorescent substance 1 (relative magnitude of the quantum yield of fluorescence) was strong.

<Creation and evaluation of device>
Using a 1.0 wt% chloroform solution of the polymeric fluorescent substance 1 synthesized in Example 1 on a glass substrate with an ITO film having a thickness of 40 nm formed by sputtering, a film having a thickness of 50 nm was formed by dipping. Next, this was dried under reduced pressure for 1 hour 80 ° C., as the electron transport layer was 70nm deposited tris (8-quinolinol) aluminum (Alq ₃₎ at a rate of 0.1 to 0.2 nm / s. Finally, a magnesium-silver alloy (Mg: Ag = 9: 1 weight ratio) was vapor-deposited at 150 nm as a cathode thereon to produce an organic EL device. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less.
When a voltage of 10.5 V was applied to the device, a current with a current density of 126 mA / cm ² flowed, and yellow-green EL emission with a luminance of 1037 cd / m ² was observed. The luminous efficiency at this time was 0.82 cd / A. The brightness was almost proportional to the current density. When the current density was further increased, the maximum luminance reached 10578 cd / m ² . Further, the EL peak wavelength was 538 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of polymeric fluorescent substance 1, and EL emission from polymeric fluorescent substance 1 was confirmed.

２５ ： ５０ ： ２５

該高分子蛍光体２のポリスチレン換算の数平均分子量は、９．８×１０³であった。該高分子蛍光体２の構造については赤外吸収スペクトル、ＮＭＲで確認した。
＜吸収、蛍光スペクトルの測定、蛍光の量子収率の評価＞
実施例１と同じ方法で蛍光強度、吸収スペクトルと蛍光スペクトルのピーク波長を求めた。高分子蛍光体２の蛍光強度は、表１に示すとおり、強かった。
＜素子の作成および評価＞
高分子蛍光体１の代わりに高分子蛍光体２を用いた以外は、実施例１と同じ方法で素子を作成した。この素子に電圧１２．３Ｖを印加したところ、電流密度０．７８９ｍＡ／ｃｍ2 の電流が流れ、輝度１４．４ｃｄ／ｍ2 の緑色のＥＬ発光が観察された。この時の発光効率は、１．８３ｃｄ／Ａであった。輝度はほぼ電流密度に比例していた。また、ＥＬピーク波長は５３０ｎｍで、高分子蛍光体２の薄膜の蛍光ピーク波長とほぼ一致しており高分子蛍光体２よりのＥＬ発光が確認された。 Example 2
<Synthesis of polymeric fluorescent substance 2>
Synthesis, washing, and reprecipitation were carried out in the same manner as in Example 1 except that 0.671 parts by weight of isophthalaldehyde and 0.671 parts by weight of terephthalaldehyde were used to obtain 3.49 parts by weight of a polymer. This is called polymeric fluorescent substance 2. The repeating unit of the polymeric fluorescent substance 2 calculated from the monomer charge ratio and its molar ratio are shown below.

25:50:25

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 2 was 9.8 × 10 ³ . The structure of the polymeric fluorescent substance 2 was confirmed by infrared absorption spectrum and NMR.
<Absorption, measurement of fluorescence spectrum, evaluation of fluorescence quantum yield>
The fluorescence intensity, the absorption spectrum, and the peak wavelength of the fluorescence spectrum were determined in the same manner as in Example 1. As shown in Table 1, the fluorescence intensity of polymeric fluorescent substance 2 was strong.
<Creation and evaluation of device>
A device was prepared in the same manner as in Example 1 except that the polymeric fluorescent substance 2 was used instead of the polymeric fluorescent substance 1. When a voltage of 12.3 V was applied to the device, a current density of 0.789 mA / cm @ 2 flowed, and green EL light emission with a luminance of 14.4 cd / m @ 2 was observed. The luminous efficiency at this time was 1.83 cd / A. The brightness was almost proportional to the current density. Further, the EL peak wavelength was 530 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of the polymeric fluorescent substance 2, and EL light emission from the polymeric fluorescent substance 2 was confirmed.

５０ ： ５０

該高分子蛍光体３のポリスチレン換算の数平均分子量は、１．０×１０⁴ であった。 Comparative Example 1
<Synthesis of polymeric fluorescent substance 3>
2,5-Diheptyloxy-p-xylylene dibromide was reacted with triphenylphosphine in an N, N-dimethylformamide solvent to synthesize a phosphonium salt. 7.4 parts by weight of this phosphonium salt and 1 part by weight of terephthalaldehyde were dissolved in ethyl alcohol. An ethyl alcohol solution containing 0.9 parts by weight of lithium ethoxide was dropped into an ethyl alcohol solution of a phosphonium salt and a dialdehyde and polymerized at room temperature for 3 hours. After standing overnight at room temperature, the precipitate was filtered off, washed with ethyl alcohol, dissolved in chloroform, and ethanol was added thereto to form a precipitate again. This was dried under reduced pressure to obtain 1.5 parts by weight of a polymer. This is called polymeric fluorescent substance 3. The repeating unit of the polymeric fluorescent substance 3 calculated from the monomer charge ratio and the molar ratio thereof are shown below.

50: 50

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 3 was 1.0 × 10 ⁴ .

<Absorption, measurement of fluorescence spectrum, evaluation of fluorescence quantum yield>
The fluorescence intensity, the absorption spectrum, and the peak wavelength of the fluorescence spectrum were determined in the same manner as in Example 1. As shown in Table 1, the fluorescent intensity of the polymeric fluorescent substance 3 was weaker than that of the polymeric fluorescent substance 1 of Example 1.
<Creation and evaluation of device>
A device was prepared in the same manner as in Example 1 except that the polymeric fluorescent substance 3 was used instead of the polymeric fluorescent substance 1. When a voltage of 10.5 V was applied to this device, a current with a current density of 20.5 mA / cm ² flowed, and yellow-green EL emission with a luminance of 98.0 cd / m ² was observed. The luminous efficiency at this time was 0.48 cd / A. The brightness was almost proportional to the current density. When the current density was further increased, the maximum luminance reached 2770 cd / m ² . Further, the EL peak wavelength was approximately 550 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of polymeric fluorescent substance 3, and EL emission from polymeric fluorescent substance 3 was confirmed.

このように、実施例１の高分子蛍光体１および実施例２の高分子蛍光体２を用いて作成した有機ＥＬ素子は、比較例１の有機ＥＬ素子よりも、非常に高い発光効率を有するなど、優れたＥＬ特性を示した。

Thus, the organic EL element produced using the polymeric fluorescent substance 1 of Example 1 and the polymeric fluorescent substance 2 of Example 2 has much higher luminous efficiency than the organic EL element of Comparative Example 1. Excellent EL characteristics were exhibited.

該高分子蛍光体４のポリスチレン換算の数平均分子量は、５×１０³であった。
該高分子蛍光体４の構造については赤外吸収スペクトル及び¹Ｈ−ＮＭＲで確認した。 Example 3
<Synthesis of polymeric fluorescent substance 4>
1.95 parts by weight of 2,5-dioctyloxyterephthalaldehyde and 0.78 parts by weight of m-phenylenediacetonitrile were dissolved in a mixed solvent of 100 parts by weight of ethyl alcohol / 100 parts by weight of chloroform. To this was added 0.3 part by weight of a 28% sodium methoxide / methanol solution, and the mixture was stirred at room temperature for 6 hours, and then 200 parts by weight of ethyl alcohol was added and left at room temperature overnight. Next, the produced precipitate was separated by filtration, washed with ethyl alcohol, washed with an ethyl alcohol / water mixed solvent and further with ethyl alcohol, and dried under reduced pressure to obtain 0.5 parts by weight of a polymer. This is referred to as polymeric fluorescent substance 4. The repeating unit of polymeric fluorescent substance 4 calculated from the monomer charge ratio is shown below.

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 4 was 5 × 10 ³ .
The structure of the polymeric fluorescent substance 4 was confirmed by an infrared absorption spectrum and ¹ H-NMR.

<Measurement of absorption and fluorescence spectra and evaluation of quantum yield of fluorescence>
The fluorescence intensity, the absorption spectrum, and the peak wavelength of the fluorescence spectrum were determined in the same manner as in Example 1. The fluorescence intensity of the thin film of polymeric fluorescent substance 4 was strong as shown in Table 2.

該高分子蛍光体５のポリスチレン換算の数平均分子量は、７×１０³であった。
該高分子蛍光体５の構造については赤外吸収スペクトル及び¹Ｈ−ＮＭＲで確認した。 Comparative Example 2
<Synthesis of polymeric fluorescent substance 5>
1.95 parts by weight of 2,5-dioctyloxyterephthalaldehyde and 0.78 parts by weight of p-phenylenediacetonitrile were dissolved in a mixed solvent of 100 parts by weight of ethyl alcohol / 100 parts by weight of chloroform. To this was added 0.3 part by weight of a 28% sodium methoxide / methanol solution, and the mixture was stirred at room temperature for 6 hours, and then 200 parts by weight of ethyl alcohol was added and left at room temperature overnight. Next, the produced precipitate was separated by filtration, washed with ethyl alcohol, washed with an ethyl alcohol / water mixed solvent and further with ethyl alcohol, and dried under reduced pressure to obtain 0.5 parts by weight of a polymer. This is called polymeric fluorescent substance 5. The repeating unit of polymeric fluorescent substance 5 calculated from the monomer charge ratio is shown below.

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 5 was 7 × 10 ³ .
The structure of the polymeric fluorescent substance 5 was confirmed by an infrared absorption spectrum and ¹ H-NMR.

このように、実施例３の高分子蛍光体４は、比較例２の高分子蛍光体５よりも、薄膜状態で高い蛍光の量子効率を有するなど、優れた蛍光特性を示した。
<Absorption, measurement of fluorescence spectrum, evaluation of fluorescence quantum yield>
The fluorescence intensity, the absorption spectrum, and the peak wavelength of the fluorescence spectrum were determined in the same manner as in Example 1. The fluorescent intensity of the polymeric fluorescent substance 5 was weak as shown in Table 2.

As described above, the polymeric fluorescent substance 4 of Example 3 showed excellent fluorescence characteristics such as having a higher quantum efficiency of fluorescence in a thin film state than the polymeric fluorescent substance 5 of Comparative Example 2.

Claims (10)

It is soluble in a solvent, has fluorescence in a solid state, has a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₃ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond, or Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. Ar ₄ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and represents an aromatic compound group or hetero atom having 6 to 22 carbon atoms involved in the conjugated bond. The shortest of two carbon atoms bonded to two adjacent vinylene groups in the chemical structure of these groups, which is selected from 6 to 20-membered heterocyclic compound groups having 4 to 20 carbon atoms In which the number of atoms continuously present in the route is 1, 3 or 5. ]
A polymeric fluorescent substance comprising a repeating unit represented by: Soluble in a solvent, having fluorescence in a solid state, having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₅ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond, or Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. Ar ₆ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and represents an aromatic compound group or hetero atom having 6 to 22 carbon atoms involved in the conjugated bond. Contained between two carbon atoms bonded to two adjacent vinylene groups in the chemical structure of these groups, which are selected from a heterocyclic compound group having 6 to 20 carbon atoms and having 6 or more carbon atoms. And the number of atoms present is one of 1, 3 or 5. ]
A polymeric fluorescent substance comprising a repeating unit represented by: Soluble in a solvent, having fluorescence in a solid state, having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ ,

[However, Ar ₇ is a bifunctional group that forms a carbon-carbon bond with two adjacent vinylene groups, and an aromatic compound group composed of 6 to 22 carbon atoms involved in the conjugated bond; Selected from five-membered or higher heterocyclic compound groups having 4 to 20 carbon atoms containing heteroatoms, and having two carbon atoms bonded to two vinylene groups adjacent in the chemical structural formula of these groups The total of the number of carbon atoms and nitrogen atoms existing continuously in the shortest path is an even number. ]
A polymeric phosphor comprising a repeating unit represented by the formula (1), wherein the repeating unit of Chemical Formula 1 is contained in an amount of 5 mol% or more of all repeating units. A copolymer that is soluble in a solvent, has fluorescence in a solid state, has a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁷ , and is composed of repeating units represented by Chemical Formula 2 and Chemical Formula 3 above. The polymeric fluorescent substance characterized by including 5 mol% or more of all repeating units.

[Wherein R _{1 to} R ₃₃ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; It is a group selected from the group consisting of 4 to 14 heterocyclic compound groups. 5. The polymeric fluorescent substance according to claim 1, 2, 3 or 4, which is selected from repeating units including a structure represented by the formula: Ar ₃ of Chemical Formula 1, Ar _{5 of} Chemical Formula 2 or Ar _{7 of} Chemical Formula ₃ contained in the polymeric fluorescent substance is represented by the following chemical formula 5,

Ar _{4 in} Chemical Formula 1 or Ar ₆ in Chemical Formula 2 is

[Wherein X is a group selected from C—R ₅₃ and N, R _{46 to} R ₅₃ are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; carbon A group selected from the group consisting of an aryl group and an aryloxy group having 6 to 18 carbon atoms; and a heterocyclic compound group having 4 to 14 carbon atoms. ]
The polymeric fluorescent substance according to claim 1, wherein the polymeric fluorescent substance is a copolymer comprising a repeating unit represented by the formula: The organic light-emitting device having at least a light-emitting layer between a pair of anode and cathode electrodes, at least one of which is transparent or translucent, wherein the light-emitting layer is according to claim 1, 2, 3, 4, 5, or 6. An organic electroluminescence device comprising a polymeric fluorescent substance. A layer comprising an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer, wherein the light emitting layer comprises the polymeric fluorescent substance according to claim 1, 2, 3, 4, 5 or 6. The organic electroluminescence element according to claim 7, wherein: The light emitting layer comprises the polymeric fluorescent substance according to claim 1, and is made of a hole transporting compound adjacent to the light emitting layer between the anode and the light emitting layer. 8. The organic electroluminescence device according to claim 7, further comprising a layer. A layer comprising an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer, wherein the light emitting layer comprises the polymeric fluorescent substance according to claim 1, 2, 3, 4, 5 or 6. 8. The organic electroluminescence device according to claim 7, wherein a layer made of a hole transporting compound is provided adjacent to the light emitting layer between the anode and the light emitting layer.