JPH09111233A - Polymeric phosphor, its production and organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high molecular phosphor composed of specific ethynylene-contg. recurring units, having high fluorescence quantum yield, soluble in solvents, excellent in luminescent layer formability through its coating and the thermal stability of such luminescent layer, thus useful for, e.g. planar light sources as backlight. SOLUTION: This high molecular phosphor has the following characteristics: soluble in organic solvents; number-average molecular weight: 10<3> -10<7> ; containing at least two kinds of recurring unit selected from those of formula I [Ar1 is an aromatic group with 6-22 carbon atoms involved in conjugated bonds (Cc ) or >=5-membered heterocyclic group with 4-20C carbon atoms including heteroatoms involved in conjugated bonds (Ch ), and the total number (Cz ) of the carbon and nitrogen atoms along the shortest path between lone bonds is even], formula II (Ar2 is a 6-22Cc aromatic group or 4-20Ch >=6-membered heterocyclic group, and Cz is 1, 3 or 5) and formula III (Ar3 and Ar4 are each a 4-20Cc aromatic group or heterocyclic group; R1 is a 1-22C hydrocarbon group or 4-22C heterocyclic group; X1 and X2 are each O, S, etc.; (m) and (n) are each 0 or 1), and the sum of these recurring units account for >=50mol% of the total recurring units in the polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymeric fluorescent substance for an organic electroluminescent device (hereinafter sometimes referred to as an organic EL device), a method for producing the same, and an organic electroluminescent device produced by using the polymeric fluorescent substance. Regarding More specifically, the present invention relates to a polymeric fluorescent substance having strong fluorescence that is soluble in a solvent, a method for producing the polymeric fluorescent substance, and an organic electroluminescent device produced using the polymeric fluorescent substance.

[0002]

2. Description of the Related Art Inorganic electroluminescent devices (hereinafter, sometimes referred to as inorganic EL devices) using an inorganic phosphor as a light emitting material are used for display devices such as a planar light source as a backlight and a flat panel display. However, a high-voltage alternating current was required to emit light. Recently, Tang et al. Used organic fluorescent dye as a light emitting layer,
An organic EL element having a two-layer structure in which this and an organic charge transport compound used for an electrophotographic photoreceptor or the like are laminated is manufactured, and an organic EL element of low voltage drive, high efficiency, and high brightness is realized. (JP-A-59-194393). Compared with inorganic EL elements, organic EL elements are characterized in that they can easily emit light of many colors in addition to low voltage driving and high brightness. Therefore, many organic EL elements have a large number of elements, organic fluorescent dyes, and organic charge transport compounds. Attempts have been reported [Japanese Journal of Applied Physics (J
pn. J. Appl. Phys. ) Volume 27, L269
Page (1988)], [Journal of Applied Physics (J. Appl. Phys.) No. 65.
Vol. 3610 (1989)].

Further, as a high molecular weight light emitting material, there are hitherto disclosed WO 9013148, JP-A-3-
No. 244630, Applied Physics Letters (Appl. Phys. Lett.) Vol. 58, 1
It was proposed on page 982 (1991). WO9
In the example of the published specification of 013148, a soluble precursor was formed into a film on an electrode and heat-treated to obtain a poly-p-phenylene vinylene thin film converted into a conjugated polymer, which was used. An EL device is disclosed. Japanese Unexamined Patent Publication (Kokai) No. 3-244630 exemplifies a conjugated polymer having a characteristic that it is soluble in a solvent and does not require heat treatment. Applied Physics
Letters (Appl. Phys. Lett.) No. 58
Vol. 1982 (1991) also describes a solvent-soluble polymeric light-emitting material and an organic EL device prepared using the same. Further, US Pat. No. 5,352,906 describes poly (p-p-), which is characterized by being thermally stable.
(Phenylene acetylene) is disclosed. Further, as a method for producing poly (p-phenylacetylene), the Chemical Society of Japan (The Chem
Ill. Society of Japan, vol. 57, p. 752 (1984), discloses a method of polymerizing an aromatic diacetylene compound and an aromatic dihalogen compound in the presence of a catalyst. In US Pat. No. 5,352,906, the polymer is obtained by the same method. Chemistry Letters
On page 1727 (1987), a method for producing the polymer by electrolytic polymerization is disclosed.

However, the polymeric fluorescent substances that have been reported so far do not have sufficient quantum yield of fluorescence, their solubility in a solvent is insufficient, or only the intermediate is soluble. Therefore, it is not always easy to make the film thinner for use as a light emitting layer of an organic EL device. Organic E that can be easily prepared by a coating method using a polymeric fluorescent substance having a high quantum yield of fluorescence and sufficient solubility in a solvent
L elements are desired.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a polymeric fluorescent substance which has a high quantum yield of fluorescence and is soluble in a solvent, a method for producing the same, and a coating method using the polymeric fluorescent substance to easily form a light emitting layer. An object of the present invention is to provide an organic electroluminescence device that can be formed and has excellent light emission characteristics.

[0006]

[Means for Solving the Problems] In view of such circumstances,
The present inventors have earnestly studied a polymeric fluorescent substance that is soluble in a solvent and has a high fluorescence yield in order to easily prepare an organic EL device using a polymeric luminous substance as a light emitting layer. As a result, they have found that a polymeric fluorescent substance having a ethynylene bond as a main chain as a polymeric light emitting substance and containing a repeating unit having a specific structure exhibits a high quantum yield of fluorescence, leading to the present invention. It was

That is, the present invention [1] is a polymer soluble in an organic solvent, wherein the polymer has a number average molecular weight of 10 ³ to
10 ⁷ and the polymer contains at least two repeating units selected from the repeating units represented by the following formulas (1), (2) and (3), and the sum of these repeating units is The present invention relates to a polymeric fluorescent substance characterized by being 50 mol% or more of the repeating unit of the polymer.

[Image Omitted] -Ar ₁ -C≡C- (1)

[Image Omitted] -Ar ₂ -C≡C- (2)

Embedded image —Ar ₃ — (X ₁ ) _m —R ₁ — (X ₂ ) _n —Ar ₄ —C≡C— (3) (wherein Ar ₁ is the number of carbon atoms involved in the conjugate bond). Is an aromatic compound group consisting of 6 or more and 22 or less or a carbon number of 4 or more and 20 containing a hetero atom involved in a conjugated bond
Number selected from 5 or more-membered ring heterocyclic compound group consisting of: the shortest path between the two groups two carbon atoms in Ar ₁ bound to an adjacent Ar ₁ in the chemical structural formulas of these groups The total number of carbon atoms and nitrogen atoms existing continuously is an even number.

Ar ₂ is an aromatic compound group having 6 to 22 carbon atoms involved in a conjugated bond or 4 to 2 carbon atoms containing a hetero atom involved in a conjugated bond.
The shortest route between two carbon atoms in Ar ₂ selected from 0 or less 6-membered or more heterocyclic compound groups and bound to two groups adjacent to Ar ₂ in the chemical structural formulas of these groups. The number of carbon atoms and nitrogen atoms continuously present in 1 is 1, 3 or 5. A
Each of r ₃ and Ar ₄ is independently a group selected from the group consisting of an aromatic group having 4 to 20 carbon atoms involved in a conjugated bond or a heterocyclic compound group.
R ₁ is a hydrocarbon group having 1 to 22 carbon atoms or a heterocyclic compound group having 4 to 22 carbon atoms, X ₁ ,
-O X ₂ are each independently -, - S -, - COO- or -OCO- indicates, m, n are each independently 0 or 1. )

Further, the present invention is [2] a polymer soluble in an organic solvent, wherein the polymer has a number average molecular weight of 10 ³ to 10 ^3.
7 , the polymer contains at least two repeating units selected from repeating units represented by the following formulas (4), (5) and (6), and the sum of these repeating units is higher than By adding a halogen to the carbon-carbon double bond of the vinylene group of the polymer compound, which is 50 mol% or more of the repeating units of the molecule, and then subjecting it to dehydrohalogenation treatment,
The invention relates to the method for producing a polymeric fluorescent substance according to [1], wherein the double bond is an ethynylene bond.

Embedded image —Ar ₁ —CH═CH— (4)

Embedded image —Ar ₂ —CH═CH— (5)

Embedded image —Ar ₃ — (X ₁ ) _m —R ₁ — (X ₂ ) _n —Ar ₄ —C═C— (6) (in the formula, Ar ₁ , Ar ₂ , Ar ₃ , Ar ₄ , and R ₁ ,
X ₁ , X ₂ , m, and n are the same as defined in [1]. )

Furthermore, the present invention [3] is an organic electroluminescence device having at least a light emitting layer between an electrode composed of a pair of an anode and a cathode, at least one of which is transparent or semitransparent, wherein the light emitting layer is [1]. The present invention relates to an organic electroluminescence device including the polymer fluorescent substance described above.

The present invention also provides [4] the organic electroluminescent device according to the above [3], further comprising a layer containing an electron transporting compound between the cathode and the light emitting layer and adjacent to the light emitting layer. The present invention relates to an organic electroluminescence device characterized by the above.

The present invention also provides [5] the organic electroluminescence device according to the above [3], further comprising a layer containing a hole transporting compound between the anode and the light emitting layer and adjacent to the light emitting layer. The present invention relates to an organic electroluminescence device characterized by being provided.

The present invention also provides [6] the organic electroluminescent device according to the above [3], further comprising a layer containing an electron transporting compound between the cathode and the light emitting layer and adjacent to the light emitting layer. The present invention relates to an organic electroluminescence device, which is characterized in that a layer containing a hole transporting compound is provided between an anode and a light emitting layer adjacent to the light emitting layer.
Hereinafter, the organic EL device of the present invention will be described in detail.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The polymeric fluorescent substance of the present invention contains at least two repeating units selected from the repeating units represented by the formulas (1), (2) and (3), and The sum of the repeating units of is 50 mol% or more of the repeating units of the polymer. The remaining repeating units may include, for example, at least two repeating units selected from the repeating units represented by formula (4), formula (5), and formula (6).

The conjugated chain length of the polymeric fluorescent substance of the present invention is preferably long from the viewpoint of charge transfer, while the conjugated chain length is short from the viewpoint of obtaining a polymeric fluorescent substance having a high quantum yield of fluorescence. Since it is better, the formula (2) and / in the polymeric fluorescent substance
Alternatively, the conjugated chain length can be set to an appropriate size by appropriately selecting the amounts of the repeating unit represented by the formula (3) and the repeating unit represented by the formula (1).

In the polymeric fluorescent substance of the present invention, Ar ₁ of the formula (1) is an aromatic compound group in which the number of carbon atoms involved in the conjugated bond is 6 or more and 22 or less, or a hetero atom involved in the conjugated bond. the above 5-membered ring consisting of 20 amino having 4 or more carbon containing selected from a heterocyclic compound group, the two of Ar ₁ bonded to two neighboring groups and Ar ₁ in the chemical structural formulas of these groups The total number of carbon atoms and nitrogen atoms existing continuously in the shortest path among carbon atoms is an even number. Here, being involved in a conjugated bond means being involved in the formation of a conjugated bond, that is, forming a conjugated bond. Specific examples of Ar ₁ include a divalent aromatic compound group represented by Chemical formula 13 or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, or a group obtained by combining them.
Here, for example, in the first group having a substituent of R ₂ , R ₃ , R ₄ , and R ₅ , the carbon atoms involved in the conjugate bond are 6 carbon atoms of the benzene ring. Also, R ₆ ,
In the second group having a substituent for R ₇ and R ₈ , the carbon atoms involved in the conjugated bond are the 5 carbon atoms of the heterocycle. Further, the fifth group having a substituent of R _{13 to} R ₁₈ has 10 carbon atoms of the naphthalene ring. Furthermore, Ar ₁ bonded to two groups adjacent to Ar ₁
In the first example above, the total number of carbon atoms and nitrogen atoms existing consecutively in the shortest path between the two carbon atoms in is between the 1-position carbon atom and the 4-position carbon atom of the phenylene group. The number of carbon atoms continuously present in the shortest path is 2, and in the second example, the number is 2 in the group containing a nitrogen atom and 4 in the fifth group.

[0017]

Embedded image

(R _{2 to} R ₃₆ are each independently hydrogen,
A group selected from the group consisting of a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group, and an alkylthio group; an aryl group having 6 to 18 carbon atoms and an aryloxy group; and a heterocyclic compound group having 4 to 14 carbon atoms. Is. Among these, phenylene group, substituted phenylene group, biphenylene group, substituted biphenylene group, naphthalenediyl group, substituted naphthalenediyl group, anthracene-9,10
-Diyl group, substituted anthracene-9,10-diyl group,
Pyridine-2,5-diyl group, substituted pyridine-2,5-
A diyl group, a thienylene group or a substituted thienylene group is preferable. More preferred are a phenylene group, a biphenylene group, a naphthalenediyl group, a pyridine-2,5-diyl group, and a thienylene group.

The substituents will be described below.
Examples of the alkyl group of 1 to 20 include a methyl group, an ethyl group,
Propyl, butyl, pentyl, hexyl, hept
Butyl, octyl, decyl, lauryl, etc.
Methyl, ethyl, pentyl, hexyl,
A heptyl group and an octyl group are preferred. Also, the number of carbon atoms is 1
Examples of the alkoxy group of 20 include methoxy group and ethoxy group.
Group, propoxy group, butoxy group, pentyloxy group,
Xyloxy group, heptyloxy group, octyloxy group
Group, decyloxy group, lauryloxy group, etc.
Methoxy group, ethoxy group, pentyloxy group, hex
Syloxy group, heptyloxy group, octyloxy group
preferable. Examples of the alkylthio group include a methylthio group and an ether group.
Cylthio group, propylthio group, butylthio group, pentyl
Thio group, hexylthio group, heptylthio group, octylti
O group, decylthio group, laurylthio group and the like,
Methylthio group, ethylthio group, pentylthio group, hex
Luthio, heptylthio, and octylthio groups are preferred.
No. As the aryl group, a phenyl group, 4-C₁~ C₁₂
Alkoxyphenyl group (C ₁~ C₁₂Has 1 to 12 carbon atoms
Indicates that there is. The same applies to the following. ), 4-C₁~ C
₁₂Alkylphenyl group, 1-naphthyl group, 2-naphthyl
Examples include groups. As an aryloxy group,
A nonoxy group is exemplified. As a heterocyclic compound group,
An enyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridy
And the like.

In the polymeric fluorescent substance of the present invention, Ar ₂ of the formula (1) has 6 or more carbon atoms involved in the conjugate bond 2
It is selected from aromatic compound groups consisting of 2 or less or heterocyclic compound groups containing 6 to 20 carbon atoms containing 4 to 20 carbon atoms containing a heteroatom involved in a conjugated bond, and the chemical structural formulas of these groups 1 is the number of carbon atoms and nitrogen atoms present continuously in the shortest path between the two carbon atoms in the Ar ₂ bonded to two neighboring groups and Ar ₂ in,
It shows that it is either 3 or 5. As Ar ₂ ,
Examples thereof include a divalent aromatic compound group represented by Chemical formula 14 or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, and a group obtained by combining them. Here, for example, 1 having a substituent of R ₃₇ , R ₃₈ , R ₃₉ , and R ₄₀
In the second group, the carbon atoms involved in the conjugated bond are
It is the 6 carbon atoms of the benzene ring. In addition, R ₄₁ ,
In the second group having a substituent of R ₄₂ and R ₄₃ , the carbon atoms involved in the conjugated bond are 5 carbon atoms of the heterocycle. Further, the fifth group having a substituent of R _{48 to} R ₅₃ has 10 carbon atoms of the naphthalene ring. Furthermore, Ar ₂ bonded to two groups adjacent to Ar ₂
In the first example above, the total number of carbon atoms and nitrogen atoms existing consecutively in the shortest path between the two carbon atoms in is between the 1-position carbon atom and the 3-position carbon atom of the phenylene group. The number of carbon atoms continuously present in the shortest route is one, and in the second example, the number of nitrogen atoms is one in the group containing a nitrogen atom, and the number of carbon atoms is five in the fifth group. Will be one.

Embedded image (R _{37 to} R ₆₉ are each independently hydrogen, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group and an alkylthio group; an aryl group having 6 to 18 carbon atoms and an aryloxy group; and 4 to 4 carbon atoms. 14 is a group selected from the group consisting of heterocyclic compound groups.) Among these, a phenylene group, a substituted phenylene group, a biphenylene group, a substituted biphenylene group, a naphthalenediyl group, a substituted naphthalenediyl group, an anthracenediyl group,
A substituted anthracenediyl group, a pyridinediyl group, and a substituted pyridinediyl group are preferable. More preferably, it is a phenylene group, a biphenylene group, a naphthalenediyl group, or a pyridinediyl group.

The substituents will be described below. As the alkyl group having 1 to 20 carbon atoms, a methyl group, an ethyl group,
Propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, lauryl group and the like, methyl group, ethyl group, pentyl group, hexyl group,
A heptyl group and an octyl group are preferred. In addition, carbon number 1
Examples of the alkoxy group of 20 include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a lauryloxy group. A group, a pentyloxy group, a hexyloxy group, a heptyloxy group and an octyloxy group are preferable. Examples of the alkylthio group include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, decylthio group, and laurylthio group.
A methylthio group, an ethylthio group, a pentylthio group, a hexylthio group, a heptylthio group and an octylthio group are preferable. As the aryl group, a phenyl group, 4-C ₁ -C ₁₂
Examples thereof include an alkoxyphenyl group, a 4-C ₁ -C ₁₂ alkylphenyl group, a 1-naphthyl group and a 2-naphthyl group. Examples of the aryloxy group include a phenoxy group. Examples of the heterocyclic compound group include 2-thienyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridyl group.

Ar ₃ and Ar ₄ are each independently an arylene group having 4 to 20 carbon atoms involved in a conjugated bond or a heterocyclic compound group, and the divalent aromatic group shown in Chemical formula 7 Examples thereof include a compound group or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, and a group obtained by combining them.

R _{1 in the} above formula (3) is a hydrocarbon group having 1 to 22 carbon atoms or a heterocyclic compound group having 4 to 22 carbon atoms, and each of X ₁ and X ₂ is independently -O.
It is a group of any one of-, -S-, -COO- and -OCO-, and m and n are 0 or 1, respectively. From the viewpoint of solubility, stability and ease of synthesis, X ₁ and X ₂ in formula (3) are each independently —O—, —COO— or —OC.
O- is preferable, and -O- is more preferable.

Further, in R ₁ of the above formula (3), the hydrocarbon includes methylene group, ethylene group, propylene group,
Butylene group, pentylene group, hexylene group, heptylene group, octylene group, decylene group, laurylene group, vinylene group, phenylene group, naphthylene group, anthrylene group and the like, propylene group, butylene group, pentylene group,
Hexylene group, heptylene group, octylene group and decylene group are preferred. Examples of the heterocyclic compound group include thienylene group, furan-2,5-diyl group, pyridine-2,3-diyl group, pyridine-2,4-diyl group, pyridine-2,
Examples thereof include a 5-diyl group and a pyridine-2,6-diyl group.

The polymeric fluorescent substance used in the present invention may be a random, block or graft copolymer, or a polymer having an intermediate structure between them, for example, a random copolymer having a block property. It may be a polymer. From the viewpoint of obtaining a copolymer having a high fluorescence quantum yield, a random copolymer having a block property or a block or graft copolymer is preferable to a completely random copolymer.
The structure of the terminal of the polymeric fluorescent substance of the present invention varies depending on the synthesis method, and examples thereof include an aldehyde group and a methyl halide group. Although it may be used as it is, the terminal may be changed to another group depending on the low molecular weight compound having a functional group capable of binding by reacting with these terminal groups. The structure of the connecting portion between the terminal group and the main chain is not particularly limited, but it is preferable that a conjugated bond is formed with the main chain via the ethynylene group. The structure of these terminal groups includes a pyrenyl group,
Examples thereof include anthryl group, naphthyl group, alkoxyphenyl group, quinolyl group and pyridyl group, and pyrenyl group and anthryl group are preferable.

Since the polymeric fluorescent substance used in the present invention can have a structure having a rigid conjugated portion and a flexible connecting portion in the main chain by combining monomers, it is basically prepared by dissolving it in a solvent. Can be membrane. Further, in order to obtain a polymer having excellent solubility and good film-forming property, an alkyl group, an alkoxy group or an alkylthio group having 4 to 20 carbon atoms; an aryl group having 6 to 18 carbon atoms or An aryloxy group; or a carbon number of 4 to 14
It is more preferable that at least one aromatic-substituted or heterocyclic-compound group, which is one or more nuclei-substituted with the heterocyclic-compound group as a substituent, is contained.

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. 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, and a lauryloxy group. , A heptyloxy group and an octyloxy group. Examples of the alkylthio group include a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group and a laurylthio group, and a pentylthio group, a hexylthio group, a heptylthio group and an octylthio group are preferable. As an aryl group,
Phenyl group, 4-C ₁ -C ₁₂ alkoxyphenyl group, 4
-C ₁ -C ₁₂ alkylphenyl group, 1-naphthyl group, 2
-Naphthyl group and the like. Examples of the aryloxy group include a phenoxy group. Examples of the heterocyclic compound group include 2-thienyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridyl group.

The number of these substituents varies depending on the molecular weight of the polymer and the conjugated chain length, but from the viewpoint of obtaining a highly soluble copolymer, the number of these substituents is preferably 1 or more per 600 of the molecular weight. More preferable.

Examples of good solvents for the polymeric fluorescent substance of the present invention include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene and xylene. Although it depends on the structure and molecular weight of the polymeric fluorescent substance,
Usually, 0.1 wt% or more can be dissolved in these solvents.

The degree of polymerization of the polymeric fluorescent substance of the present invention is not particularly limited, and varies depending on the repeating structure and the ratio thereof. From the viewpoint of film formability, the total number of repeating structures is preferably 4 to 10,000, more preferably 4 to 3,000, and particularly preferably 5 to 2,000.

In the case of forming a film from a solution by using these organic solvent-soluble polymers in the production of an organic EL device, it is sufficient to remove the solvent by coating the solution and then drying it. The same method can be applied to the case where the transportation materials are mixed, which is very advantageous in manufacturing.

Examples of the method for producing the polymeric fluorescent substance of the present invention include a method of polymerizing an aromatic dihalo compound and an aromatic bisacetylene compound in the presence of a palladium catalyst, and an aromatic bis (trihalogenated methyl) compound. Examples thereof include a method of reducing and polymerizing, particularly a method of electrochemically reducing. However, these methods are not very advantageous from an industrial point of view, because the method for synthesizing the monomer is complicated and an electrolytic device is required.

The method for producing a polymeric fluorescent substance of the present invention is a polymer soluble in an organic solvent, and the number average molecular weight of the polymer is 10 ³ to 10 ⁷ , and the polymer has the above formula ( 4), at least two repeating units selected from the repeating units represented by formula (5) and formula (6), and the sum of these repeating units is 50 mol% or more of the repeating units of the polymer. After adding a halogen to the carbon-carbon double bond of the vinylene group of the polymer compound, by dehydrohalogenation treatment, the double bond is an ethynylene bond, the synthesis of the monomer is easy, Further, since an electrolytic device is not required, it is an industrially superior method as compared with the known method, and is particularly preferable.

In this case, the method of halogenation is not particularly limited, but it is preferable that the aromatic ring is not substituted with halogen. For example, a method of adding bromine in an inert organic solvent such as carbon tetrachloride under cooling is exemplified.

The method for the dehydrohalogenation treatment is not particularly limited, but a dehydrohalogenation reaction with a base is preferable. For example, a method of dehydrohalogenating with potassium hydroxide or potassium alcoholate in an alcohol solvent is exemplified.

Regarding the structure of the organic EL device of the present invention,
In the light emitting layer provided between the pair of electrodes, at least one of which is transparent or semitransparent, as long as the light emitting material comprising the polymeric fluorescent substance of the present invention is used, there is no particular limitation, and a known structure is adopted. It For example, a pair of electrodes is provided on both sides of a light emitting layer made of the polymeric fluorescent substance or a light emitting layer made of a mixture of the polymeric fluorescent substance and a charge transporting material (collective term of electron transporting material and hole transporting material). Having a structure having, further between the cathode and the light emitting layer, adjacent to the light emitting layer and containing an electron transport material, and / or between the anode and the light emitting layer, adjacent to the light emitting layer. An example is one in which a hole transport layer containing a hole transport material is laminated. The present invention also includes a case where the light emitting layer and the charge transport layer are one layer and a case where a plurality of layers are combined. Further, for example, a light emitting material other than the polymeric fluorescent substance described below may be mixed and used in the light emitting layer. Further, it is also possible to form a layer in which the polymeric fluorescent substance and / or the charge transport material is dispersed in a polymeric compound.

As the charge transporting material used with the polymeric fluorescent substance of the present invention, that is, as the electron transporting material or the hole transporting material, known materials can be used and are not particularly limited.
Examples of the hole transport material include a pyrazoline derivative, an arylamine derivative, a stilbene derivative, a triphenyldiamine derivative, poly (N-vinylcarbazole), polyaniline and its derivative, polythiophene and its derivative, poly (p-phenylenevinylene) and its derivative, Examples of the electron transport material include poly (2,5-thienylene vinylene) and its derivatives, and examples of the electron transport material include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives. , Tetracyanoanthraquinodimethane and its derivatives, fluorenone derivatives, diphenyldicyanoethylene and its derivatives, diphenoquinone derivatives, 8-hydroxyquinoline and its derivatives, metal complexes and the like.

Specifically, JP-A-63-70257, JP-A-63-175860, and JP-A-2-1353.
Nos. 59, 2-135361, 2-209
988, 3-37992, 3-152
No. 184 is exemplified. Triphenyldiamine derivatives and poly (N-vinylcarbazole) are used as hole transport materials, oxadiazole derivatives, benzoquinone and its derivatives are used as electron transport materials,
A metal complex of anthraquinone and its derivative, 8-hydroxyquinoline and its derivative is preferable, and in particular, 4,4′-bis (N (3-methylphenyl) -N-phenylamino) biphenyl, poly ( N-vinylcarbazole) is preferable, and as the electron transport material, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8- Quinolinol) aluminum is preferred. Of these, either one of the electron transporting compound and the hole transporting compound, or both of them may be used at the same time. These may be used alone,
Two or more types may be used as a mixture.

When the charge transport layer is provided between the light emitting layer and the electrode, these charge transport materials may be used to form the charge transport layer. When the charge transporting material is used in a mixture with the light emitting layer, the amount of the charge transporting material varies depending on the kind of the compound to be used. It may be determined appropriately in consideration of the situation. Usually, it is 1 to 40% by weight, more preferably 2 to 30% by weight, based on the light emitting material.

The known light emitting material that can be used with the polymeric fluorescent substance used in the present invention is not particularly limited.
For example, naphthalene derivatives, anthracene and its derivatives, perylene and its derivatives, polymethine-based, xanthene-based, coumarin-based, cyanine-based dyes, 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, JP-A-57-5
Known materials such as those described in Japanese Patent Nos. 1781 and 59-194393 can be used.

Next, a typical method for producing the organic EL device of the present invention will be described. As a pair of electrodes consisting of an anode and a cathode, the transparent or semitransparent electrode is a transparent substrate such as glass or transparent plastic on which a transparent or semitransparent electrode is formed. As the material of the anode,
A conductive metal oxide film, a semitransparent metal thin film, or the like is used. Specifically, indium tin oxide (IT
O), a film (NESA or the like) formed using conductive glass made of tin oxide, Au, Pt, Ag, Cu or the like is used. As a manufacturing method, a vacuum evaporation method, a sputtering method, a plating method, or the like is used.

Next, a light emitting layer containing the above polymeric fluorescent substance as a light emitting material is formed on this anode. Examples of the forming method include a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method and a roll coating method using a solution, a mixed solution or a molten solution of these materials. It is particularly preferable to form the 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 preferably 0.5 n
m to 10 μm, more preferably 1 nm to 1 μm.
10 to 50 to increase the current density and luminous efficiency
The range of 0 nm is preferred. In addition, when a thin film is formed by a coating method, in order to remove the solvent, it is desirable to heat-dry under reduced pressure or in an inert atmosphere at a temperature of 30 to 200 ° C., preferably 60 to 100 ° C.

When the light emitting layer and the charge transporting layer (meaning a general term for the hole transporting layer and the electron transporting layer) are laminated, the anode is formed on the anode before the light emitting layer is formed by the above film forming method. It is preferable to form a hole transporting layer on the substrate and / or to form an electron transporting layer on the light emitting layer after forming the light emitting layer.

The film formation method of the charge transport layer is not particularly limited, but it is a vacuum deposition method from a powder state, or a spin coating method after being dissolved in a solution, a casting method,
A coating method such as a dipping method, a bar coating method, a roll coating method, or a spin coating method, a casting method, a dipping method, a bar coating method in which a polymer compound and a charge transport material are mixed and dispersed in a solution state or a molten state. A coating method such as a coating method or a roll coating method can be used.
The polymer compound to be mixed is not particularly limited,
Those that do not extremely disturb the charge transport are preferable, and those that do not strongly absorb visible light are preferably used.

For example, poly (N-vinylcarbazole), polyaniline and its derivatives, polythiophene and its derivatives, poly (p-phenylenevinylene) and its derivatives, poly (2,5-thienylenevinylene) and its derivatives, polycarbonate, Examples include polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polysiloxane and the like. It is preferable to use a coating method in that the film can be easily formed.

The film thickness of the charge transport layer needs to be at least such that pinholes are not generated, but if it is too thick, the resistance of the device increases and a high driving voltage is required, which is not preferable. Therefore, the thickness of the charge transport layer is preferably 0.5 nm to 10 μm, more preferably 1 nm to 1 μm.
m, particularly preferably 5 to 200 nm.

Next, an electrode is provided on the light emitting layer or the electron transporting 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, C
a, Li, Mg-Ag alloy, In-Ag alloy, Mg-I
n alloy, Mg-Al alloy, Mg-Li alloy, Al-Li
An alloy, a graphite thin film or the like is used. As a method for manufacturing the cathode, a vacuum evaporation method, a sputtering method, or the like is used.

[0049]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Example 1 <Element structure> An example of the organic EL element of the present invention will be described.
An ITO transparent electrode, a hole transport layer, a polymer light emitting layer, an electron transport layer, and a back electrode are laminated on a glass substrate. <Synthesis of polymeric fluorescent substance 1> 2,5-dioctyloxy-
The phosphonium salt was synthesized by reacting p-xylylene dichloride with triphenylphosphine in N, N-dimethylformamide. Obtained phosphonium salt 9.55
g, isophthalaldehyde 0.67 g, and terephthalaldehyde 0.67 g were dissolved in ethyl alcohol. An ethyl alcohol solution containing 1.56 g of lithium ethoxide was added dropwise to 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 and then dissolved in chloroform. Ethanol was added to this solution for reprecipitation purification. This was dried under reduced pressure to obtain a polymer.

3.0 g of this polymer was added to 120 g of carbon tetrachloride.
Was dissolved. To this solution, 3.1 g of bromine was added to carbon tetrachloride 2
A solution dissolved in 0 g was added dropwise, followed by stirring at room temperature for 2 hours,
Bromination of the polymer was performed. After the solution was concentrated at room temperature, ethanol was added to it and the precipitate formed was recovered.
This was washed with ethanol and then dried under reduced pressure to obtain 5 g of a brominated polymer. Next, a dehydrohalogenation reaction was performed. A solution prepared by dissolving 2.73 g of the brominated polymer in 70 g of xylene was added dropwise to a solution prepared by dissolving 3.14 g of potassium tertiary butoxide in 70 g of tert-butanol and raising the temperature to 70 ° C. Subsequently, the mixture was reacted at 90 ° C. for 7 hours.
After cooling this solution, it was poured into a large amount of methanol and the formed precipitate was recovered. The precipitate was washed with ethanol. Next, this precipitate was dissolved in chloroform. Ethanol was added to this solution for reprecipitation purification. This is dried under reduced pressure to give 0.5 g of a polymer having an ethynylene group.
I got This is called polymeric fluorescent substance 1.

The polystyrene reduced number average molecular weight of the polymeric fluorescent substance 1 was 7.0 × 10 ⁴ . Here, regarding 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. The structure of the polymeric fluorescent substance 1 was confirmed by infrared absorption spectrum and NMR.

<Measurement of Fluorescence Intensity> Polymeric fluorescent substance 1 was dissolved in chloroform. The 0.4% chloroform solution was spin-coated on a quartz plate to obtain a polymer thin film. The fluorescence spectrum of this thin film was measured using a fluorescence spectrophotometer 850 manufactured by Hitachi, Ltd. To calculate the quantum yield of fluorescence,
The fluorescence spectrum when excited at 410 nm was used.
The fluorescence intensity was determined as a relative value by dividing the area of the fluorescence spectrum plotted by plotting the wave number on the horizontal axis by the absorbance at 410 nm. Table 1 shows the fluorescence intensity (relative value) of the resulting polymeric fluorescent substance 1.

<Production and Evaluation of Element> 1.0 wt% of the polymeric fluorescent substance 1 synthesized in Example 1 was deposited on a glass substrate having an ITO film with a thickness of 40 nm by sputtering.
A chloroform solution was spin-coated to form a film having a thickness of 50 nm. Then, this is depressurized to 80
After drying at 0 ° C. for 1 hour, an aluminum-lithium alloy (Al: Li = 100: 1 weight ratio) as a cathode was vapor-deposited thereon to a thickness of 150 nm 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 is applied to this element, blue-green light emission is recognized.

Example 2 <Synthesis of polymeric fluorescent substance 2> 2,5-dioctyloxy-
The phosphonium salt was synthesized by reacting p-xylylene dichloride with triphenylphosphine in N, N-dimethylformamide. 12 g of the obtained phosphonium salt
2.05 g of a dialdehyde compound obtained by reacting p-hydroxybenzaldehyde with potassium hydroxide in an ethyl alcohol solvent to give potassium phenolate, and then reacting this with 1,6-dibromune-hexane.
And 0.85 g of isophthalaldehyde were dissolved in an ethyl alcohol / chloroform mixed solvent. 1.56g
Was added dropwise to an ethyl alcohol / chloroform 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 and then dissolved in chloroform. Ethanol was added to this solution for reprecipitation purification. This was dried under reduced pressure to obtain a polymer. 5.0 g of this polymer was dissolved in 120 g of carbon tetrachloride. To this solution, 4.2 g of bromine and 20 g of carbon tetrachloride
The solution dissolved in was added dropwise and then stirred at room temperature for 2 hours to brominate the polymer. The solution was concentrated at room temperature, ethanol was added to the solution, and the formed precipitate was collected, washed with ethanol, and dried under reduced pressure to obtain 8.9 g of a brominated polymer.

Next, a dehydrohalogenation reaction was performed. 70 g of tert-butanol and 4.48 tert-butoxy potassium
A solution prepared by dissolving 4.46 g of the brominated polymer in 80 g of xylene was added dropwise to a solution in which g was dissolved and the temperature was raised to 70 ° C. Subsequently, the mixture was reacted at 90 ° C. for 7 hours. After cooling this solution, it was poured into a large amount of methanol and the formed precipitate was recovered. The precipitate was washed with ethanol.
Next, this precipitate was dissolved in chloroform. Ethanol was added to this solution for reprecipitation purification. This was dried under reduced pressure to obtain 0.9 g of a polymer having an ethynylene group. This is called polymeric fluorescent substance 2. The polystyrene reduced number average molecular weight of the polymeric fluorescent substance 2 was 2.0 × 10 ⁴ .
Here, regarding the number average molecular weight, chloroform is used as a solvent and gel permeation chromatography (G
The number average molecular weight in terms of polystyrene was determined by (PC). The structure of the polymeric fluorescent substance 2 was confirmed by infrared absorption spectrum and NMR.

<Measurement of Fluorescence Intensity> Table 1 shows the fluorescence intensity (relative value) of the polymeric fluorescent substance 2 obtained by measurement in the same manner as in Example 1.

<Production and Evaluation of Device> 1.0 wt% of the polymeric fluorescent substance 2 synthesized in Example 2 on a glass substrate having an ITO film with a thickness of 40 nm attached by sputtering.
A chloroform solution was spin-coated to form a film having a thickness of 50 nm. Then, this is depressurized to 80
After drying at 0 ° C. for 1 hour, an aluminum-lithium alloy (Al: Li = 100: 1 weight ratio) as a cathode was vapor-deposited thereon to a thickness of 150 nm 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 is applied to this element, blue light emission is recognized.

Comparative Example 1 <Synthesis of polymeric fluorescent substance 3> 70 g of tert-butyl alcohol
A solution of 6.7 g of potassium tertiary-butoxy in was heated to about 70 ° C., and 8.6 g of 2,5-dioctyloxy-p-xylylene dichloride was added to this solution.
After the solution dissolved in g was dropped, the mixture was reacted at about 90 ° C. for 7 hours. After cooling the solution, it was poured into a large amount of methanol, and a red precipitate was formed. After recovering this precipitate, it was washed with methanol, then with a mixed solvent of ethanol / water, and further with ethanol. Next,
This precipitate was dissolved in chloroform. Ethanol was added to this solution for reprecipitation purification. This was dried under reduced pressure to obtain poly (2,5-dioctyloxy-p-phenylene vinylene). 1.07 g of this polymer was added to 50 g of carbon tetrachloride.
Was dissolved. Add 1 g of bromine to 10 g of carbon tetrachloride in this solution.
The solution dissolved in was added dropwise and then stirred at room temperature for 2 hours to brominate the polymer. Ethanol was added to this solution, the formed precipitate was collected, washed with ethanol, and then dried under reduced pressure to obtain a brominated polymer. Next, a dehydrohalogenation reaction was performed. A solution of 1.02 g of the brominated polymer dissolved in 30 g of xylene was added dropwise to a solution of potassium tertiary butoxide dissolved in tert-butanol and the temperature was raised to 70 ° C. Subsequently, the mixture was reacted at 90 ° C. for 7 hours. After cooling this solution, it was poured into a large amount of methanol and the formed precipitate was recovered. The precipitate was washed with ethanol and dried under reduced pressure to give a polymer having an ethynylene group of 0.
2 g was obtained. This is called polymeric fluorescent substance 3.

The polystyrene reduced number average molecular weight of the polymeric fluorescent substance 3 was 1.8 × 10 ⁴ . Here, regarding 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. The structure of the polymeric fluorescent substance 3 was confirmed by infrared absorption spectrum and NMR.

<Measurement of Fluorescence Intensity> Table 1 shows the fluorescence intensity (relative value) of the polymeric fluorescent substance 3 obtained in the same manner as in Example 1. The fluorescent intensities of polymeric fluorescent substances 1 and 2 were strong as shown in Table 1.

[Table 1]

[0061]

INDUSTRIAL APPLICABILITY The polymeric fluorescent substance of the present invention has a high quantum yield of fluorescence and is soluble in a solvent, and is suitable as a light emitting material for an organic EL device, a dye for a dye laser, and the like. Can be used. Further, since the light emitting layer can be easily formed by the coating method, the organic EL element can be easily produced. Furthermore, since the organic EL device using the polymer light-emitting body of the present invention uses a thermally stable polymer fluorescent substance, a planar light source as a backlight,
It can be preferably used as a device such as a flat panel display.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H05B 33/14 H05B 33/14 (72) Inventor Yoshihiko Tsuchida 6 Kitahara, Tsukuba, Ibaraki Sumitomo Chemical Co., Ltd. In the company

Claims (7)

[Claims] 1. A polymer soluble in an organic solvent, wherein the polymer has a number average molecular weight of 10 ³ to 10 ⁷ , and the polymer has the following formulas (1), (2) and ( A polymeric fluorescent substance comprising at least two repeating units selected from the repeating units represented by 3), and the sum of these repeating units is 50 mol% or more of the repeating units of the polymer. Embedded image —Ar ₁ —C≡C— (1) embedded image —Ar ₂ —C≡C— (2) embedded image —Ar ₃ — (X ₁ ) _m —R ₁ — (X ₂ ) _N- Ar ₄ -C≡C- (3) (In the formula, Ar ₁ is an aromatic compound group in which the number of carbon atoms involved in the conjugated bond is 6 or more and 22 or less, or hetero involved in the conjugated bond. 20 carbon atoms containing 4 or more
Number selected from 5 or more-membered ring heterocyclic compound group consisting of: the shortest path between the two groups two carbon atoms in Ar ₁ bound to an adjacent Ar ₁ in the chemical structural formulas of these groups The total number of carbon atoms and nitrogen atoms existing continuously is an even number. Ar ₂ is an aromatic compound group having 6 to 22 carbon atoms involved in a conjugated bond or a 6-membered ring having 4 to 20 carbon atoms containing a hetero atom involved in a conjugated bond A heterocyclic compound group selected from the following, and carbon atoms present continuously in the shortest path between two carbon atoms in Ar ₂ bonded to two groups adjacent to Ar ₂ in the chemical structural formulas of these groups; The number of nitrogen atoms is 1, 3 or 5. Ar ₃ and Ar ₄ are each independently a group selected from the group consisting of an aromatic group having 4 to 20 carbon atoms involved in a conjugated bond or a heterocyclic compound group. R ₁ has 1 to 22 carbon atoms
The following hydrocarbon groups or heterocyclic compound groups having 4 or more and 22 or less carbon atoms, wherein X ₁ and X ₂ are each independently -O.
Represents-, -S-, -COO- or -OCO-, and m, n
Are independently 0 or 1. ) 2. The polymeric fluorescent substance according to claim 1, wherein the polymer is an alternating copolymer, a random copolymer or a block copolymer. 3. A polymer soluble in an organic solvent, wherein the polymer has a number average molecular weight of 10 ³ to 10 ⁷ , and the polymer has the following formulas (4), (5) and ( The carbon-carbon of the vinylene group of the polymer compound containing at least two repeating units selected from the repeating units represented by 6), and the sum of these repeating units is 50 mol% or more of the repeating units of the polymer. The method for producing a polymeric fluorescent substance according to claim 1 or 2, wherein the double bond is converted into an ethynylene bond by adding a halogen to the double bond and then subjecting it to dehydrohalogenation treatment. Embedded image —Ar ₁ —CH═CH— (4) —Ar ₂ —CH═CH— (5) —Ar ₃ — (X ₁ ) _m —R ₁ — (X _{2 ) n -Ar 4 -C = C- (} 6) ( _{wherein, Ar 1, Ar 2, Ar} 3, Ar 4, R 1,
X ₁ , X ₂ , m, and n are the same as defined in claim 1. ) 4. An organic electroluminescent device having at least a light emitting layer between a pair of electrodes consisting of an anode and a cathode, at least one of which is transparent or semitransparent,
An organic electroluminescence device, wherein the light emitting layer comprises the polymeric fluorescent substance according to claim 1 or 2. 5. The organic electroluminescent device according to claim 4, further comprising a layer containing an electron transporting compound between the cathode and the light emitting layer and adjacent to the light emitting layer. Electroluminescent device. 6. The organic electroluminescence device according to claim 4, further comprising a layer containing a hole transporting compound between the anode and the light emitting layer and adjacent to the light emitting layer. Organic electroluminescent device. 7. The organic electroluminescence device according to claim 4, further comprising a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer, and an anode and the light emitting layer. And a layer containing a hole transporting compound adjacent to the light emitting layer.