JP2000303066A - Polymeric phosphor and polymeric luminescent element prepared by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phosphor which exhibits a strong fluorescence by selecting a phosphor which has such characteristics that it state exhibits a fluorescence in the solid; the mol.wt. is in a specific range; it contains two kinds of repeating units; the ratio of the sum of the contents of the two kinds of repeating units to the total repeating units is a specified value or higher; and the ratio of the content of one kind of the two kinds of repeating units to the sum of the contents of the two kinds is in a specified range. SOLUTION: The number average mol.wt. in terms of polystyrene is 5×104-1×108. The two kinds of repeating units are represented by formulas I and II. The sum of the contents of repeating units represented by formulas I and II is 50 mol. % or higher, and the content of repeating units represented by formula I to the sum of the contents of repeating units represented by formulas I and II is 0.1-9 mol %. In the formulas Ar1 is an arylene group having 6-60 carbon atoms in the main chain or a divalent heterocyclic group having 4-60 carbon atoms in the main chain; (m) is an integer of 1-4; X is O or S; R3 is a 5-20C alkyl, or the like; (n) is 0 or 1; Ar2 is the same as Ar1; (k) is an integer of 1-4; and (l) is 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer phosphor and a polymer light emitting device using the same (hereinafter, may be referred to as a polymer LED).

[0002]

2. Description of the Related Art Inorganic electroluminescent elements (hereinafter sometimes referred to as inorganic EL elements) using an inorganic phosphor as a light emitting material are used, for example, in a planar light source as a backlight or a display device such as a flat panel display. However, a high voltage AC was required to emit light.

In recent years, an organic electroluminescent device (hereinafter referred to as 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 for an electrophotographic photoreceptor or the like is laminated. In some cases) (JP-A-59-194393). Compared to inorganic EL elements, organic EL elements are characterized by low voltage driving, high luminance, and easy emission of many colors. Attempts have been reported [Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.) 27
Volume, page L269 (1988)], [Journal of Applied Physics (J. Appl.
s. ) 65, 3610 (1989)].

Further, apart from the organic EL device mainly using a low molecular weight organic compound, a polymer LED using a high molecular weight luminescent material is disclosed in WO901148, JP-A-3-244630, and Applied. Physics Letters (Appl. Phys. Let
t. Vol. 58, p. 1982 (1991), and the examples of WO 903148 include examples in which a soluble precursor is formed on an electrode and heat-treated to form a conjugated polymer. Poly (p-phenylenevinylene) (hereinafter sometimes referred to as PPV)
A thin film can be obtained and an element using the thin film is disclosed.

Further, JP-A-3-244630 exemplifies a conjugated polymer having a feature that it is soluble in a solvent itself and does not require heat treatment. Applied Physics Letters (Appl.
s. Lett. Vol. 58, p. 1982 (1991)
Describes a polymer light-emitting material soluble in a solvent and a polymer LED produced using the same.

[0006] Since the polymer LED can easily form an organic layer by coating, it is advantageous in increasing the area and cost as compared with the case of depositing a low-molecular phosphor.
It is considered that the film has excellent mechanical strength because it is a polymer.

Conventionally, as a polymer fluorescent substance used for these polymer LEDs, besides the above-mentioned poly (p-phenylenevinylene), polyfluorene (Japanese Journal of Applied Physics (Jpn.
Appl. Phys. ) Vol. 30, p. L1941 (19
1991)), polyparaphenylene derivatives (Advanced Materials (Adv. Mater.) Vol. 4, 36)
Page (1992)). As described above, in the polymer LED, a polymer phosphor having strong fluorescence has been demanded.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymer phosphor having strong fluorescence and a high-performance polymer LED which can be driven at a low voltage and with high efficiency by using the polymer phosphor.
Is to provide.

[0009]

The present inventors have made intensive studies in view of such circumstances, and as a result, it has been found that a polymeric fluorescent substance containing a specific repeating unit has a particularly strong fluorescence, and The present inventors have found that a high-performance polymer LED that can be driven with low voltage and high efficiency can be obtained by using a molecular phosphor, and the present invention has been achieved.

That is, the present invention provides [1] fluorescence in a solid state and a polystyrene equivalent number average molecular weight of 5 × 10 ⁴
１1 × 10 ⁸ , and the following formulas (1) and (2)
Wherein at least 50 mol% of all repeating units are present, and the total of repeating units represented by formulas (1) and (2) is The present invention relates to a polymeric fluorescent substance in which the repeating unit represented by the formula (1) is 0.1 mol% or more and 9 mol% or less.

[0011]

Embedded image ... (1) [where Ar ₁ is an arylene group containing 6 to 60 carbon atoms in the main chain, or 4 carbon atoms in the main chain. It is a divalent heterocyclic compound group consisting of at least 60 but not more than 60. When Ar ₁ has a plurality of substituents, they may be the same or different. m is an integer of 1 to 4. X represents oxygen or sulfur. R ₃ is an alkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, and 7 to 60 carbon atoms.
And a group selected from the group consisting of arylalkyl groups and heterocyclic compound groups having 4 to 60 carbon atoms. R ₁ and R ₂ are each independently a group selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, a heterocyclic compound group having 4 to 60 carbon atoms, and a cyano group. Is shown. n
Is 0 or 1. ]

[0012]

Embedded image ... (2) [where Ar ₂ is an arylene group containing 6 to 60 carbon atoms in the main chain, or 4 carbon atoms in the main chain. It is a divalent heterocyclic compound group consisting of at least 60 but not more than 60. k is an integer of 1-4. R ₆ is an alkyl group having 5 to 20 carbon atoms, 7 to
And a group selected from the group consisting of 60 arylalkyl groups. When Ar ₂ has a plurality of substituents, they may be the same or different. R
₃ and R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, and 4 to 60 carbon atoms.
And a group selected from the group consisting of a heterocyclic compound group and a cyano group. l is 0 or 1. The present invention also provides [2] a polymer light emitting device having a light emitting layer between a pair of anodes and cathodes at least one of which is transparent or translucent; The present invention relates to a polymer light emitting device contained therein.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a polymer phosphor of the present invention and a polymer LED using the same will be described in detail.
The polymer fluorescent substance of the present invention has fluorescence in a solid state, has a number average molecular weight of 5 × 10 ⁴ to 1 × 10 ⁸ in terms of polystyrene, and has a repeating structure represented by the above formulas (1) and (2). Each of which contains one or more kinds of units, wherein the total of the repeating units is 50 mol% or more of all the repeating units, and the total of the repeating units represented by the formulas (1) and (2) is represented by the formula (1) Is a polymer fluorescent substance in which the repeating unit represented by is 0.1 mol% or more and 9 mol% or less. Although it depends on the structure of the repeating unit, the content of the repeating unit represented by the formula (1) is preferably from 0.2 mol% to 8 mol%.

Ar ₁ and Ar ₂ each independently represent an arylene group containing 6 to 60 carbon atoms in the main chain, or 4 to 60 carbon atoms in the main chain. Or less heterocyclic compound groups.

Ar ₁ and Ar ₂ may be selected so as not to impair the fluorescent characteristics of the polymeric fluorescent substance. Specific examples are shown in the following chemical formulas (5), (6), (7) and (8). And divalent groups.

[0016]

Embedded image

[0017]

Embedded image

[0018]

Embedded image

[0019]

Embedded image

Here, in the case of Ar ₁ , R is hydrogen,
Or a substituent represented by -X-R ₃ but, Ar ₁ is -
The substituent represented by X-R ₃ is selected to have one to four. In the case of Ar _2, R is hydrogen, or a substituent represented by R _6, Ar ₂ is selected to have one to four substituents represented by R _6. In the example above,
Although one structural formula has a plurality of Rs, they may be the same or different, and each is independently selected. In order to increase the solubility in a solvent, it is preferable that the shape of the repeating unit including the substituent be less symmetric.

X represents oxygen or sulfur, and oxygen is particularly preferred. R ₃ is a group selected from the group consisting of an alkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, an arylalkyl group having 7 to 60 carbon atoms, and a heterocyclic compound group having 4 to 60 carbon atoms. is there.

Specific examples of the alkyl group having 5 to 20 carbon atoms include a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and a lauryl group. Groups, octyl and decyl groups are preferred.

The aryl group having 6 to 60 carbon atoms includes a phenyl group and a C ₁ -C ₁₂ alkoxyphenyl group (C ₁ -C ₁₂
Indicates that the number of carbon atoms is 1 to 12. The same applies to the following. ), C ₁ -C ₁₂ alkylphenyl group, 1-naphthyl group, 2-naphthyl group and the like, C ₁ -C ₁₂ alkoxyphenyl group, is C ₁ -C ₁₂ alkylphenyl group are preferable.

An arylalkyl group having 7 to 60 carbon atoms
Phenylmethyl group, phenylethyl group, phenyl
Propyl group, C₁~ C₁₂An alkoxyphenylmethyl group,
C₁~ C₁₂Alkoxyphenylethyl group, C₁~ C₁₂Al
Coxyphenylpropyl group, C₁~ C₁₂Alkylpheny
Methyl group, C₁~ C₁₂Alkylphenylethyl group, C ₁
~ C₁₂Alkylphenylpropyl group, naphthylmethyl
Group, naphthylethyl group, naphthylpropyl group, etc.
And C₁~ C₁₂Alkoxyphenylmethyl group, C₁~ C
₁₂Alkoxyphenylethyl group, C₁~ C₁₂Alkoxy
Phenylpropyl group, C₁~ C₁₂Alkyl phenyl meth
Group, C₁~ C₁₂Alkylphenylethyl group, C₁~ C₁₂
Alkylphenylpropyl groups are preferred.

Examples of the heterocyclic compound group having 4 to 60 carbon atoms include a thienyl group, a C ₁ -C ₁₂ alkylthienyl group, a pyrrolyl group, a furyl group, a pyridyl group, and a C ₁ -C ₁₂ alkylpyridyl group. a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyridyl group, a C ₁ -C ₁₂ alkyl pyridyl group are preferable.

R ₆ is a group selected from the group consisting of an alkyl group having 5 to 20 carbon atoms and an arylalkyl group having 7 to 60 carbon atoms.

Specific examples of the alkyl group having 5 to 20 carbon atoms include a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and a lauryl group. Groups, octyl and decyl groups are preferred.

The arylalkyl group having 7 to 60 carbon atoms includes phenylmethyl group, phenylethyl group, phenylpropyl group, C ₁ -C ₁₂ alkoxyphenylmethyl group,
C ₁ -C ₁₂ alkoxyphenyl ethyl, C ₁ -C ₁₂ alkoxy phenylpropyl, C ₁ -C ₁₂ alkylphenyl methyl group, C ₁ -C ₁₂ alkyl phenylethyl group,
C ₁ -C ₁₂ alkyl-phenylpropyl group, naphthylmethyl group, naphthylethyl group, etc. naphthyl propyl group and the like, C ₁ -C ₁₂ alkoxyphenyl methyl group, C ₁ ~
C ₁₂ alkoxyphenyl ethyl, C ₁ -C ₁₂ alkoxy phenylpropyl, C ₁ -C ₁₂ alkylphenyl methyl group, C ₁ -C ₁₂ alkyl phenylethyl group, C ₁ -C
_{A 12-} alkylphenylpropyl group is preferred.

Among the examples of R, in the substituent containing an alkyl chain, they may be linear, branched or cyclic, or a combination thereof. A 2-ethylhexyl group, a 3,7-dimethyloctyl group, a cyclohexyl group,
Examples thereof include a 4-C ₁ -C ₁₂ alkylcyclohexyl group. In order to enhance the solubility of the polymeric fluorescent substance in the solvent, it is preferable that at least one of the substituents of Ar ₁ or Ar ₂ contains a cyclic or branched alkyl chain.

In the above formula (1), n is 0 or 1.
In the above formula (2), 1 is 0 or 1.
R in the above formula (1)₁, R_TwoAnd the above equation (2)
R _Four, R_FiveIs independently hydrogen, carbon number 1-20
An alkyl group, an aryl group having 6 to 60 carbon atoms, and 4 carbon atoms
From the group consisting of heterocyclic compound groups and cyano groups
Shows the selected group.

In the case where R ₁ , R ₂ , R ₄ , and R ₅ are hydrogen or a substituent other than a cyano group, the number of carbon atoms is one.
Examples of the alkyl group to -20 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 nonyl group, a decyl group, and a lauryl group. , A pentyl group, a hexyl group, a heptyl group and an octyl group are preferred.

The aryl group having 6 to 60 carbon atoms includes a phenyl group, a C ₁ -C ₁₂ alkoxyphenyl group, a C ₁ -C ₁₂
Alkylphenyl group, 1-naphthyl group, 2-naphthyl group and the like, a phenyl group, the C ₁ -C ₁₂ alkylphenyl group are preferable.

Examples of the heterocyclic compound group having 4 to 60 carbon atoms include a thienyl group, a C ₁ -C ₁₂ alkylthienyl group, a pyrrolyl group, a furyl group, a pyridyl group, and a C ₁ -C ₁₂ alkylpyridyl group. a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyridyl group, a C ₁ -C ₁₂ alkyl pyridyl group are preferable.

The terminal group of the polymeric fluorescent substance is protected by a stable group, since if the polymerization active group remains as it is, the light emission characteristics and the life of the device may be reduced. Is preferred. Those having a conjugated bond continuous with the conjugated structure of the main chain are more preferable, and examples thereof include a structure in which the conjugated structure is bonded to an aryl group or a heterocyclic compound group via a vinylene group. Specifically, Japanese Patent Application Laid-Open No. 9-4
Substituents described in Chemical Formula 10 of JP-A-5478 are exemplified.

As a method for synthesizing the polymeric fluorescent substance, when a main chain has a vinylene group, for example, Japanese Patent Laid-Open No. 5-202
No. 355, for example. That is, Wit of a dialdehyde compound and a diphosphonium salt compound
Polymerization by tig reaction, Hec of divinyl compound and dihalogen compound or Hec of vinylhalogen compound alone
Polymerization by k reaction, Horner-Wadsworth-E of dialdehyde compound and diphosphite compound
polymerization by the Monmons method, polycondensation of a compound having two methyl halide groups by a dehydrohalogenation method, polycondensation of a compound having two sulfonium bases by a sulfonium salt decomposition method, Knoevenagel reaction of a dialdehyde compound and a diacetonitrile compound And a method such as polymerization with

When the main chain does not have a vinylene group, for example, a method of polymerizing the corresponding monomer by a Suzuki coupling reaction, a method of polymerizing with an oxidizing agent such as FeCl _3, a method of electrochemical oxidative polymerization Or a method by decomposition of an intermediate polymer having an appropriate leaving group.

The polymer fluorescent substance has the formulas (1) and (2) as long as the fluorescent properties and the charge transport properties are not impaired.
And repeating units other than those represented by. Further, the repeating units represented by the formulas (1) and (2) and other repeating units may be linked by a non-conjugated unit having an ether group, an ester group, an amide group, an imide group, or the like, The non-conjugated portion may be contained in the repeating unit. The polymeric fluorescent substance may be a random, block, or graft copolymer, or may be a polymer having an intermediate structure between them, for example, a random copolymer having a block property. . From the viewpoint of obtaining a polymeric fluorescent substance having a high quantum yield of fluorescence, a random copolymer having block properties or a block or graft copolymer is preferable to a complete random copolymer. The case where the main chain is branched and there are three or more terminal portions is also included.

Further, since light emission from a thin film is used, a polymer fluorescent substance having fluorescence in a solid state is preferably used. Examples of good solvents for the polymeric fluorescent substance include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene, mesitylene, decalin, and n-butylbenzene. Although it depends on the structure and molecular weight of the polymeric fluorescent substance, it can be usually dissolved in these solvents in an amount of 0.1% by weight or more.

The polymeric fluorescent substance has a molecular weight of 5 × 10 ⁴ to 1 × 10 ⁸ in terms of polystyrene, and the degree of polymerization thereof varies depending on the repeating structure and its ratio. In general, the total number of repeating structures is preferably from 20 to 10,000, more preferably from 30 to 1,000, from the viewpoint of film forming properties.
0, particularly preferably 50 to 5000.

When these polymer fluorescent materials are used as a light emitting material of a polymer LED, since the purity affects the light emitting characteristics, the monomer before polymerization is purified by a method such as distillation, sublimation purification, recrystallization and the like. Is preferably polymerized to
After the synthesis, it is preferable to carry out a purification treatment such as reprecipitation purification or fractionation by chromatography.

Next, the polymer LED of the present invention will be described. As the structure of the polymer LED of the present invention, in a polymer LED having a light emitting layer between electrodes composed of a pair of anodes and cathodes, at least one of which is transparent or translucent, It must be included in the layer. Further, as the polymer LED of the present invention, a polymer LED provided with an electron transport layer between the cathode and the light emitting layer, a polymer LED provided with a hole transport layer between the anode and the light emitting layer, Examples include a polymer LED in which an electron transport layer is provided between a cathode and a light emitting layer, and a hole transport layer is provided between an anode and a light emitting layer. For example, the following structures a) to d) are specifically exemplified. a) anode / light-emitting layer / cathode b) anode / hole-transport layer / light-emitting layer / cathode c) anode / light-emitting layer / electron-transport layer / cathode d) anode / hole-transport layer / light-emitting layer / electron-transport layer / cathode (Here, / indicates that the respective layers are stacked adjacently. The same applies hereinafter.)

Here, the light emitting layer is a layer having a function of emitting light, the hole transport layer is a layer having a function of transporting holes, and the electron transport layer is a layer having a function of transporting electrons. It is a layer which has. Note that the electron transport layer and the hole transport layer are collectively referred to as a charge transport layer. The light emitting layer, the hole transporting layer, and the electron transporting layer may be each independently used in two or more layers.

Further, among the charge transport layers provided adjacent to the electrodes, the charge transport layer has a function of improving the charge injection efficiency from the electrodes,
Those having the effect of lowering the driving voltage of the element are generally called a charge injection layer (hole injection layer, electron injection layer) in particular.

Further, in order to improve the adhesion to the electrode and the charge injection from the electrode, the above-mentioned charge injection layer or an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode.
A thin buffer layer may be inserted at the interface between the charge transport layer and the light emitting layer in order to improve adhesion at the interface and prevent mixing. The order and number of layers to be stacked and the thickness of each layer can be appropriately used in consideration of luminous efficiency and device life.

In the present invention, a polymer LED provided with a charge injection layer (electron injection layer, hole injection layer) includes a polymer LED provided with a charge injection layer adjacent to a cathode, and a charge LED adjacent to an anode. There is a polymer LED provided with an injection layer.
For example, the following structures e) to p) are specifically mentioned. e) anode / charge injection layer / emission layer / cathode f) anode / emission layer / charge injection layer / cathode g) anode / charge injection layer / emission layer / charge injection layer / cathode h) anode / charge injection layer / hole Transport layer / light emitting layer / cathode i) anode / hole transport layer / light emitting layer / charge injection layer / cathode j) anode / charge injection layer / hole transport layer / light emitting layer / charge injection layer / cathode k) anode / charge Injection layer / light-emitting layer / charge transport layer / cathode l) anode / light-emitting layer / electron transport layer / charge injection layer / cathode m) anode / charge injection layer / light-emitting layer / electron transport layer / charge injection layer / cathode n) anode / Charge injection layer / Hole transport layer / Emitting layer / Charge transport layer / Cathode o) Anode / Hole transport layer / Emitting layer / Electron transport layer / Charge injection layer / Cathode p) Anode / Charge injection layer / Hole transport Layer / light-emitting layer / electron transport layer / charge injection layer / cathode

As a specific example of the charge injection layer, a layer containing a conductive polymer, provided between the anode and the hole transport layer,
A layer containing a material having an ionization potential of an intermediate value between the anode material and the hole transport material contained in the hole transport layer, provided between the cathode and the electron transport layer, and included in the cathode material and the electron transport layer Examples include a layer containing a material having an electron affinity of an intermediate value between the electron transport material and the like.

When the charge injection layer is a layer containing a conductive polymer, the conductive polymer has an electric conductivity of 10 ⁻⁵ S / cm.
Above 10 is preferably ³ or less, and for decreasing leak current between light emitting pixels, 10 ^-5 S / cm or more 1
It is more preferably 0 ² or less, and further preferably 10 ^-5 S / cm or more and 10 ¹ or less. Usually, an appropriate amount of ions is doped into the conductive polymer so that the electric conductivity of the conductive polymer is 10 ⁻⁵ S / cm or more and 10 ³ or less.

The type of ions to be doped is an anion for the hole injection layer and a cation for the electron injection layer.
Examples of anions include polystyrenesulfonate, alkylbenzenesulfonate, camphorsulfonate, and the like, and examples of cations include lithium, sodium, potassium, and tetrabutylammonium. The thickness of the charge injection layer is, for example, 1 nm to 100 nm, and preferably 2 nm to 50 nm.

The material used for the charge injection layer may be appropriately selected depending on the relationship with the electrodes and the materials of the adjacent layers. Polyaniline and its derivatives, polythiophene and its derivatives, polyphenylenevinylene and its derivatives, polythienylenevinylene and its materials Examples thereof include conductive polymers such as derivatives, metal phthalocyanines (eg, copper phthalocyanine), and carbon.

The insulating layer having a thickness of 2 nm or less has a function of facilitating charge injection. Examples of the material for the insulating layer include metal fluorides, metal oxides, and organic insulating materials. Polymer LE provided with an insulating layer having a thickness of 2 nm or less
Examples of D include a polymer LED provided with an insulating layer having a thickness of 2 nm or less adjacent to a cathode, and a polymer LED provided with an insulating layer having a thickness of 2 nm or less adjacent to an anode.

Specifically, the following structures q) to ab) are exemplified. q) Anode / Insulating layer having a thickness of 2 nm or less / Emitting layer / Cathode r) Anode / Emitting layer / Insulating layer having a thickness of 2 nm or less s) Anode / Insulating layer having a thickness of 2 nm or less / Emitting layer / 2n thickness
m) Insulating layer / cathode t or less t) Anode / insulating layer / thickness 2 nm or less / hole transporting layer / light emitting layer / cathode u) Anode / hole transporting layer / luminescent layer / insulating layer / thickness 2 nm or less / cathode v A) Anode / insulating layer having a thickness of 2 nm or less / hole transporting layer / light emitting layer / insulating layer having a thickness of 2 nm or less / cathode w) anode / insulating layer having a thickness of 2 nm or less / emitting layer / electron transporting layer / cathode x) Anode / light-emitting layer / electron transport layer / insulating layer with thickness of 2 nm or less / cathode y) anode / insulating layer with thickness of 2 nm or less / light-emitting layer / electron transport layer / insulating layer with thickness of 2 nm or less / cathode z) anode / Aa) anode / hole transport layer / light emitting layer / electron transport layer / film thickness 2n; insulating layer having a thickness of 2 nm or less / hole transport layer / light emitting layer / electron transport layer / cathode
a) Insulating layer / Hole transporting layer / Emitting layer / Electron transporting layer / Insulating layer having a thickness of 2 nm or less / Cathode

When a polymer LED is prepared, by using these organic solvent-soluble polymer fluorescent materials to form a film from a solution, it is only necessary to remove the solvent by drying after coating this solution. The same method can be applied to a case where a transport material and a light-emitting material are mixed, which is very advantageous in production. As a method of forming a film from a solution, a spin coating method, a casting method, a microgravure coating method,
Coating methods such as gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, screen printing, flexographic printing, offset printing, and inkjet printing can be used.

The optimum value of the thickness of the light emitting layer depends on the polymer fluorescent substance used, and may be selected so that the driving voltage and the luminous efficiency have appropriate values. For example, it is 1 nm to 1 μm, preferably 2 nm to 500 nm,
More preferably, it is 5 nm to 200 nm.

For example, a light emitting material other than the polymeric fluorescent substance may be mixed and used in the light emitting layer. As the light emitting material, known materials can be used. Examples of low molecular compounds include naphthalene derivatives, anthracene or derivatives thereof, perylene or derivatives thereof, polymethine-based, xanthene-based, coumarin-based, and cyanine-based dyes, metal complexes of 8-hydroxyquinoline or its derivatives, and aromatic amines. , Tetraphenylcyclopentadiene or a derivative thereof, or tetraphenylbutadiene or a derivative thereof can be used.

Specifically, for example, Japanese Patent Application Laid-Open No. 57-5178
Known ones such as those described in JP-A Nos. 1 and 59-194393 can be used.

When the polymer LED of the present invention has a hole transport layer, the hole transport material used may be polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, or a polysiloxane derivative having an aromatic amine in a side chain. , Pyrazoline derivatives, arylamine derivatives,
Examples include a stilbene derivative, a triphenyldiamine derivative, polyaniline or a derivative thereof, polythiophene or a derivative thereof, poly (p-phenylenevinylene) or a derivative thereof, and poly (2,5-thienylenevinylene) or a derivative thereof.

Specifically, examples of the hole transport material include JP-A-63-70257, JP-A-63-175860, JP-A-2-135359 and JP-A-2-13536.
No. 1, JP-A-2-209988, JP-A-3-3799
No. 2, JP-A-3-152184, etc. are exemplified.

Among these, as a hole transporting material used for the hole transporting layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or Derivatives thereof, polythiophene or derivatives thereof, poly (p-phenylenevinylene)
Or a derivative thereof, or a polymer hole transporting material such as poly (2,5-thienylenevinylene) or a derivative thereof, and more preferably polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof,
A polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular-weight hole transport material, it is preferable to use the material by dispersing it in a polymer binder.

Polyvinylcarbazole or a derivative thereof can be obtained, for example, from a vinyl monomer by cation polymerization or radical polymerization.

As the polysilane or a derivative thereof,
Chemical Review (Chem. Rev.) Vol. 89,
1359 (1989), British Patent GB230019
Compounds described in No. 6 published specification are exemplified. Although the synthesis methods described above can be used as the synthesis method, the Kipping method is particularly preferably used.

Polysiloxane or its derivative has almost no hole transporting property in the siloxane skeleton structure.
Those having the structure of the low-molecular-weight hole transporting material in the side chain or main chain are preferably used. In particular, those having a hole transporting aromatic amine in the side chain or main chain are exemplified.

The method for forming the hole transport layer is not limited.
In the case of the low-molecular-weight hole transport material, a method of forming a film from a mixed solution with a polymer binder is exemplified. In the case of a polymer hole transport material, a method of forming a film from a solution is exemplified.

The solvent used for film formation from a solution is not particularly limited as long as it can dissolve the hole transport material.
As the solvent, chloroform, methylene chloride, chlorine solvents such as dichloroethane, ether solvents such as tetrahydrofuran, aromatic hydrocarbon solvents such as toluene and xylene, acetone, ketone solvents such as methyl ethyl ketone,
Ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate are exemplified.

As a method of forming a film from a solution, spin coating from a solution, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and the like. Method, screen printing method, flexographic printing method,
A coating method such as an offset printing method and an inkjet printing method can be used.

As the polymer binder to be mixed, those which do not extremely inhibit charge transport are preferable, and those which do not strongly absorb visible light are suitably used. Examples of the polymer binder include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

The optimum value of the thickness of the hole transporting layer depends on the material used, and may be selected so that the driving voltage and the luminous efficiency have appropriate values. Is necessary, and if it is too thick,
The driving voltage of the device is undesirably high. Therefore, the thickness of the hole transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

In the present invention, when the polymer LED has an electron transporting layer, known electron transporting materials can be used, such as oxadiazole derivative, anthraquinodimethane or its derivative, benzoquinone or its derivative. , Naphthoquinone or its derivative, anthraquinone or its derivative, tetracyanoanthraquinodimethane or its derivative, fluorenone derivative, diphenyldicyanoethylene or its derivative,
Examples thereof include a diphenoquinone derivative, 8-hydroxyquinoline or a metal complex of a derivative thereof, 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.

Of these, oxadiazole derivatives,
Benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, or a metal complex of 8-hydroxyquinoline or a derivative thereof is preferable, and 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,3 is preferable.
4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are more preferred.

As a method of forming the electron transport layer, a vacuum evaporation method from a powder or a method of forming a film from a solution or a molten state is used for a low molecular electron transport material, and a solution or a molten state is used for a polymer electron transport material. The method by film formation from each is exemplified. When forming a film from a solution or a molten state, a polymer binder may be used in combination.

The solvent used for film formation from a solution is not particularly limited as long as it can dissolve the electron transport material and / or the polymer binder. As the solvent, chloroform, methylene chloride, chlorine solvents such as dichloroethane, ether solvents such as tetrahydrofuran, aromatic hydrocarbon solvents such as toluene and xylene, acetone, ketone solvents such as methyl ethyl ketone, ethyl acetate, butyl acetate, Ester solvents such as ethylcellosolve acetate are exemplified.

The film forming method from the solution or molten state includes spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and the like. A coating method such as a printing method, a screen printing method, a flexographic printing method, an offset printing method, and an inkjet printing method can be used.

As the polymer binder to be mixed, those which do not extremely inhibit charge transport are preferable, and those which do not strongly absorb visible light are preferably used. Examples of the polymer binder include poly (N-vinylcarbazole), polyaniline or a derivative thereof, polythiophene or a derivative thereof, poly (p-phenylenevinylene) or a derivative thereof, poly (2,5-thienylenevinylene) or a derivative thereof, and polycarbonate. , Polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, or polysiloxane.

The optimum value of the film thickness of the electron transporting layer depends on the material used, and may be selected so that the driving voltage and the luminous efficiency have appropriate values. Necessary and too thick,
The driving voltage of the device is undesirably high. Therefore, the film thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

The substrate for forming the polymer LED of the present invention comprises:
Any material can be used as long as it can form an electrode and apply a light emitting layer, and examples thereof include glass, plastic, a polymer film, and a silicon substrate. In the case of an opaque substrate, the opposite electrode is preferably transparent or translucent.

In the present invention, the anode side is preferably transparent or translucent. As the material of the anode, a conductive metal oxide film, a translucent metal thin film or the like is used. Specifically, indium tin oxide (IT
O), zinc oxide (ZnO), tin oxide (SnO ₂ ), and other conductive films made of conductive glass (NESA, etc.), gold, platinum, silver, copper, etc., and ITO, Zn
O and SnO ₂ are preferred. Examples of the manufacturing method include a vacuum evaporation method, a sputtering method, an ion plating method, and a plating method. Further, as the anode, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used.

As the material of the cathode used in the polymer LED of the present invention, a material having a small work function is preferable. For example,
Aluminum, indium, magnesium, calcium, lithium, magnesium-silver alloy, magnesium-
Indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy,
Calcium-aluminum alloy, graphite or graphite intercalation compound is used.

As a method for producing the cathode, a vacuum deposition method, a sputtering method, a lamination method for thermocompression bonding a metal thin film, and the like are used. After producing the cathode, a protective layer for protecting the polymer LED may be attached. In order to use the polymer LED stably for a long time, it is preferable to attach a protective layer and / or a protective cover to protect the element from the outside.

As the protective layer, polymer compounds, metal oxides, metal fluorides, metal borides and the like can be used. Further, as the protective cover, a glass plate, a plastic plate having a surface subjected to low water permeability treatment, or the like can be used. Used for If the space is maintained by using the spacer, it is easy to prevent the element from being damaged. By enclosing an inert gas such as nitrogen or argon in the space, it is possible to prevent oxidation of the cathode, and furthermore, by installing a desiccant such as barium oxide in the space, the moisture adsorbed in the manufacturing process can be prevented. Can be easily prevented from damaging the element. It is preferable to take any one or more of these measures.

To obtain a planar element using the polymer LED of the present invention, a planar anode and a planar cathode may be arranged so as to overlap. Further, in order to obtain patterned light emission, a method in which a mask having a patterned window provided on the surface of the planar light emitting element is provided. A method for emitting light, one of an anode and a cathode, or both electrodes may be formed in a pattern. Further, in order to form a dot matrix element, both the anode and the cathode may be formed in a stripe shape and arranged orthogonally. By separately applying a plurality of types of polymer phosphors having different emission colors, partial color display and multi-color display can be performed.

[0081]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto. 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. Example 1 <Synthesis of polymeric fluorescent substance 1> p- (2-ethylhexyl)
2 g of bromomethylated toluene and 2-methoxy-5-
After 0.067 g of (2-ethylhexyloxy) -p-xylene dichloride was dissolved in 350 g of dry 1,4-dioxane, the mixture was degassed by bubbling with nitrogen for 15 minutes, and then the reaction solution was heated to 95 ° C. To this solution, a solution of 1.4 g of potassium tert-broxide / 20 g of dry 1,4-dioxane was added dropwise in 5 minutes. After the temperature of the solution was raised to 97 ° C., a solution of 1.2 g of potassium t-bromoxide / 15 g of dry 1,4-dioxane was added dropwise. 2 at 98 ° C
Allowed to react for hours. After the reaction, the mixture was cooled to 50 ° C.
A mixture of 4-dioxane was added for neutralization. After allowing to cool to room temperature, the reaction solution was poured into stirred ion-exchanged water. Next, the deposited precipitate was separated by filtration and washed with methanol. This was dried under reduced pressure to obtain 0.3 g of a polymer. next,
This was dissolved in tetrahydrofuran, poured into methanol, and purified by reprecipitation. The precipitate was washed with ethanol and dried under reduced pressure to obtain polymeric fluorescent substance 1.

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 1 was 6.4 × 10 ⁴ . The structure of the polymeric fluorescent substance 1 was determined by ¹ H-NMR using 2-methyl-5- (2-ethylhexyl) -p-phenylenevinylene and 2-methoxy-5- (2-ethylhexyloxy) -p-phenylene. A spectrum corresponding to an approximately 92: 8 copolymer of vinylene was obtained.

Example 2 <Synthesis of polymeric fluorescent substance 2> 2.44 g of 2,5-dioctyl-p-xylylenedibromide and 2methoxy-5- (2
-Ethylhexyloxy) p-xylylene dichloride 0.13 g was dissolved in xylene 150 g, and tert.
A solution prepared by dissolving 3.36 g of potassium butoxy in 30 g of THF was added dropwise at room temperature, followed by a reaction at room temperature for 7 hours. Next, this reaction solution was poured into methanol containing 1.8 ml of glacial acetic acid, and the resulting red precipitate was formed.
Filtered and collected.

Next, this precipitate was washed with ethanol, then repeatedly washed with a mixed solvent of ethanol / ion-exchanged water, and finally washed with ethanol. This was dried under reduced pressure to obtain 1.5 g of a polymer. Next, this polymer was dissolved in chloroform. The polymer solution was poured into methanol and purified by reprecipitation. After collecting the precipitate, it was dried under reduced pressure to obtain polymeric fluorescent substance 2.

The polystyrene-equivalent number average molecular weight of the polymeric fluorescent substance 2 was 4.0 × 10 ⁵ . The structure of the polymeric fluorescent substance 2 was determined by ¹ H-NMR to be 2,5.
A spectrum corresponding to an approximately 96: 4 copolymer of -dioctyl-p-phenylenevinylene and 2-methoxy-5- (2-ethylhexyloxy) -p-phenylenevinylene was obtained.

Example 3 <Synthesis of polymeric fluorescent substance 3> 2.44 g of 2,5-dioctyl-p-xylylenedibromide and 2methoxy-5- (2
-Ethylhexyloxy) p-xylylene dichloride (0.21 g) was dissolved in dry 1,4-dioxane (300 g), bubbled with nitrogen for 15 minutes, degassed, and then heated to 90 ° C. To this solution, a solution of 1.4 g of potassium tert-broxide / 20 g of dry 1,4-dioxane was added dropwise in 5 minutes. After the temperature of the solution was raised to 97 ° C., a solution of 1.2 g of potassium t-bromoxide / 15 g of dry 1,4-dioxane was added dropwise. The reaction was allowed to proceed at 95 ° C. for 3 hours. After the reaction, the reaction mixture was cooled to 50 ° C.
-A mixture of dioxane was added for neutralization. After allowing to cool to room temperature, the reaction solution was poured into stirred ion-exchanged water. Next, the deposited precipitate was separated by filtration and washed with ethanol. This was dried under reduced pressure to obtain 1.1 g of a polymer. next,
After dissolving this in chloroform, it was poured into methanol and purified by reprecipitation. The precipitate was washed with ethanol and dried under reduced pressure to obtain polymeric fluorescent substance 3.

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 3 was 3.6 × 10 ⁵ . The structure of the polymeric fluorescent substance 3 was determined by ¹ H-NMR to be 2,5-
Dioctyl-p-phenylenevinylene and 2-methoxy-
A spectrum corresponding to an approximately 92: 8 copolymer of 5- (2-ethylhexyloxy) -p-phenylenevinylene was obtained.

Example 4 <Synthesis of polymeric fluorescent substance 4> 2.44 g of 2,5-dioctyl-p-xylylene dibromide and 0.17 g of 2,5-dioctyloxy p-xylylene dichloride were dissolved in 150 g of xylene. After a solution obtained by dissolving 3.36 g of potassium tert-butoxy in 30 g of THF was added dropwise to the solution at room temperature, the reaction was continued at room temperature for 7 hours. Next, this reaction solution was poured into methanol containing 1.8 ml of glacial acetic acid, and the resulting red precipitate was collected by filtration. Next, the precipitate was washed with ethanol, then repeatedly washed with a mixed solvent of ethanol / ion-exchanged water, and finally washed with ethanol. This was dried under reduced pressure to obtain 1.3 g of a polymer. Next, this polymer was dissolved in chloroform. Pour this polymer solution into methanol,
It was purified by reprecipitation. After collecting the precipitate, the precipitate was dried under reduced pressure to obtain polymeric fluorescent substance 4.

The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 4 was 4.0 × 10 ⁵ . The structure of the polymeric fluorescent substance 4 was determined by ¹ H-NMR to be 2,5-
A spectrum corresponding to an approximately 96: 4 copolymer of dioctyl-p-phenylenevinylene and 2,5-dioctyloxy-p-phenylenevinylene was obtained.

Comparative Example 1 <Synthesis of polymeric fluorescent substance 5> 2-Methoxy-5- (2-ethylhexyloxy) p-xylylene dichloride
A solution of 6.72 g of tert-butoxy potassium dissolved in 30 g of THF was added dropwise at room temperature to a solution of 32 g dissolved in 300 g of THF, followed by a reaction at room temperature for 7 hours. Next, this reaction solution was poured into methanol containing 3.5 ml of glacial acetic acid, and the resulting red precipitate was collected by filtration. Next, the precipitate is washed with ethanol,
Subsequently, the substrate was repeatedly washed with a mixed solvent of ethanol / ion-exchanged water, and finally, washed with ethanol. This was dried under reduced pressure to obtain 1.3 g of a polymer. Next, this polymer was dissolved in toluene. The polymer solution was poured into methanol and purified by reprecipitation. After collecting the precipitate, the precipitate was dried under reduced pressure to obtain polymeric fluorescent substance 5.

The polystyrene-equivalent number average molecular weight of the polymeric fluorescent substance 5 was 9.9 × 10 ⁴ . The structure of the polymeric fluorescent substance 5 was determined by ¹ H-NMR to be poly (2).
-Methoxy-5- (2-ethylhexyloxy) -p
-Phenylene vinylene).

Comparative Example 2 <Synthesis of polymeric fluorescent substance 6> 2.44 g of 2,5-dioctyl-p-xylylenedibromide and 2methoxy-5- (2
-Ethylhexyloxy) p-xylylene dichloride (1.66 g) dissolved in xylene (100 g) was added with tert.
A solution obtained by dissolving 6.72 g of potassium butoxy in 30 g of THF was added dropwise at room temperature, followed by a reaction at room temperature for 7 hours. Next, this reaction solution was poured into methanol containing 3.5 ml of glacial acetic acid, and the resulting red precipitate was formed.
Filtered and collected. Next, the precipitate was washed with ethanol, then repeatedly washed with a mixed solvent of ethanol / ion-exchanged water, and finally washed with ethanol. This was dried under reduced pressure to obtain 1.7 g of a polymer. Next, this polymer was dissolved in chloroform. The polymer solution was poured into methanol and purified by reprecipitation. After collecting the precipitate, the precipitate was dried under reduced pressure to obtain polymeric fluorescent substance 6.

The polystyrene-equivalent number average molecular weight of the polymeric fluorescent substance 6 was 6.0 × 10 ⁵ . The structure of the polymeric fluorescent substance 6 was determined by ¹ H-NMR to be 2,5-
Dioctyl-p-phenylenevinylene and 2-methoxy-
A spectrum corresponding to an approximately 50:50 copolymer of 5- (2-ethylhexyloxy) -p-phenylenevinylene was obtained.

Example 5 <Measurement of Absorption Spectrum and Fluorescence Spectrum> The polymeric fluorescent substances 1 to 6 could be dissolved in chloroform.
The 0.1% chloroform solution was spin-coated on a quartz plate to form a polymer thin film. The UV-visible absorption spectrum and the fluorescence spectrum of this thin film were measured by using a self-recording spectrophotometer UV365 (manufactured by Shimadzu Corporation) and a fluorescence spectrophotometer 85, respectively.
0 (manufactured by Hitachi, Ltd.). In each polymeric fluorescent substance, the fluorescence spectrum when excited at 410 nm is plotted by taking the wave number on the horizontal axis to obtain the area.
The fluorescence intensity (relative value) was determined by dividing by the absorbance at 10 nm. As shown in Table 1, the polymeric fluorescent substances 1-4 of Examples 1-4 are the polymeric fluorescent substances 5 of Comparative Examples 1-2.
It had fluorescence stronger than 6.

[Table 1]

Example 6 <Preparation and evaluation of device>
A 100 nm thick film was formed by spin coating using a 0.4 wt% chloroform solution of the polymeric fluorescent substance 1 on a glass substrate provided with an ITO film having a thickness of 5 nm. Further, this was dried at 80 ° C. for 1 hour under reduced pressure, and then, as a cathode, calcium was vapor-deposited at 25 nm and then aluminum was vapor-deposited at 40 nm to produce a polymer LED. The degree of vacuum at the time of vapor deposition is
All were 1 to 8 × 10 ⁻⁶ Torr. By applying a voltage to the obtained device, the E-
L emission was obtained. The luminous efficiency was 3.3 cd / A.

[0096]

The polymer fluorescent substance having a specific repeating unit according to the present invention has strong fluorescence and can be suitably used as a polymer LED or a dye for laser. Further, a polymer LED using the polymer fluorescent substance has a low voltage,
High luminous efficiency. Therefore, the polymer LED can be preferably used for devices such as a curved or planar light source as a backlight, a segment type display element, and a dot matrix flat panel display.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/22 H05B 33/22 Z (72) Inventor Makoto Kitano 6 Kitahara, Tsukuba, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. F term (reference) 3K007 AB02 AB03 AB06 AB18 BA06 CA01 CA03 CA05 CA06 CB01 DA00 DB03 EB00 FA01 4J002 CE001 FD116 GP00 4J032 BA04 BA05 BA09 BA14 BB03 BB09 BC03 BC12 CA04 CA07 CA12 CA14 CA43 CA45 CA53 CA22 CB04 CD03 CE01

Claims (7)

[Claims] The compound has fluorescence in a solid state, has a polystyrene-equivalent number average molecular weight of 5 × 10 ⁴ to 1 × 10 ⁸ , and has a repeating unit represented by the following formulas (1) and (2): And at least 50 mol% of all repeating units, and the total of repeating units represented by formulas (1) and (2) is represented by the formula (1) A polymeric fluorescent substance having a unit of 0.1 mol% or more and 9 mol% or less. Embedded image ... (1) [where Ar ₁ is an arylene group containing 6 to 60 carbon atoms in the main chain, or 4 carbon atoms in the main chain. It is a divalent heterocyclic compound group consisting of at least 60 but not more than 60. When Ar ₁ has a plurality of substituents, they may be the same or different. m is an integer of 1 to 4. X represents oxygen or sulfur. R ₃ is an alkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, and 7 to 60 carbon atoms.
And a group selected from the group consisting of arylalkyl groups and heterocyclic compound groups having 4 to 60 carbon atoms. R ₁ and R ₂ are each independently a group selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, a heterocyclic compound group having 4 to 60 carbon atoms, and a cyano group. Is shown. n
Is 0 or 1. [Chemical formula 2] ... (2) [where Ar ₂ is an arylene group containing 6 to 60 carbon atoms in the main chain, or 4 carbon atoms in the main chain. It is a divalent heterocyclic compound group consisting of at least 60 but not more than 60. k is an integer of 1-4. R ₆ is an alkyl group having 5 to 20 carbon atoms,
And a group selected from the group consisting of 60 arylalkyl groups. When Ar ₂ has a plurality of substituents, they may be the same or different. R
₃ and R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 60 carbon atoms, and 4 to 60 carbon atoms.
And a group selected from the group consisting of a heterocyclic compound group and a cyano group. l is 0 or 1. ] 2. A polymer light emitting device having a light emitting layer between a pair of anodes and cathodes, at least one of which is transparent or translucent, wherein the polymer phosphor according to claim 1 is contained in said light emitting layer. A polymer light-emitting device, characterized by being included in: 3. The polymer light emitting device according to claim 2, wherein a layer containing a conductive polymer is provided between at least one electrode and the light emitting layer, adjacent to said electrode. 4. The polymer light emitting device according to claim 2, wherein an insulating layer having a thickness of 2 nm or less is provided between at least one electrode and the light emitting layer, adjacent to said electrode. 5. The polymer light emitting device according to claim 2, wherein a layer made of an electron transporting compound is provided between the cathode and the light emitting layer, adjacent to the light emitting layer. element. 6. The polymer according to claim 2, wherein a layer made of a hole transporting compound is provided between the anode and the light emitting layer, adjacent to the light emitting layer. Light emitting element. 7. A layer comprising an electron transporting compound between the cathode and the light emitting layer, adjacent to the light emitting layer, and a hole transporting layer between the anode and the light emitting layer, adjacent to the light emitting layer. The polymer light-emitting device according to any one of claims 2 to 4, wherein a layer made of a compound is provided.