JPH1077467A - Production of organic electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for commercially producing an organic electroluminescence element having a large area on a large scale. SOLUTION: This method is an improved method for the production of an organic electroluminescence element having a luminescent layer between an anode and a cathode which is formed on a surface of a polymer film and is transparent or translucent. This method comprises producing continuously a film of a luminescent material containing a luminescent polymer which has recurring units represented by the formula: -Ar-CR=CR'- wherein Ar is a divalent aromatic hydrocarbon group or a heterocyclic group each having from 4 to 20 carbon atoms participating in conjugated bonding, and each of R and R' independently represents a member selected from the group consisting of a hydrogen atom, a 1-20C alkyl group, a 6-20C aryl group, a 4-20C heterocyclic group and cyano group, in an amount of 50 mole % or more based on the total recurring units in the polymer, and which has a number average molecular weight of 10<3> to 10<7> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic electroluminescent device (hereinafter, sometimes referred to as an organic EL device) formed using a polymeric fluorescent substance.

[0002]

2. Description of the Related Art An inorganic EL device using an inorganic phosphor as a light emitting material (hereinafter sometimes referred to as an inorganic EL device).
Are used in, for example, a planar light source as a backlight or a display device such as a flat panel display, but a high-voltage AC is required to emit light. In recent years, Ta
ng et al. prepared an organic EL device having a two-layer structure in which an organic fluorescent dye was used as a light-emitting layer, and an organic charge-transporting compound used for an electrophotographic photoreceptor or the like was laminated (JP-A-59-194393). No.). Organic EL elements are inorganic E
Compared to the L element, many attempts have been reported on the element structure, organic fluorescent dyes, and organic charge transport compounds because they have characteristics that light emission of many colors can be easily obtained in addition to low voltage driving, high luminance, and the like. [Japanese Journal of Applied Physics (Jpn. J. App.
l. Phys. ) Vol. 27, p. L269 (1988)
Year)], [Journal of Applied Physics (J. Appl. Phys.) 65, 3610 (1989)].

Heretofore, low-molecular-weight organic fluorescent dyes have been generally used as a material for the light-emitting layer.
Examples of the high molecular weight light emitting material include WO901148, JP-A-3-244630, and Applied Physics Letters (Appl. Phys. Le).
tt. Vol. 58, p. 1982 (1991). Examples of WO 903148 discloses that a poly (p-phenylenevinylene) thin film converted into a conjugated polymer can be obtained by forming a soluble precursor on an electrode and performing a heat treatment. The EL element used is disclosed. Also, Japanese Patent Application Laid-Open No. 3-244
No. 630 exemplifies a conjugated polymer which is soluble in a solvent itself and does not require heat treatment. Applied Physics Letters (A
ppl. Phys. Lett. Vol. 58, p. 1982 (1991) also describes a polymer light-emitting material soluble in a solvent and an organic EL device prepared using the same. Also, a flexible organic EL device has been reported. For example, JP-A-6-124785 discloses that an electrode made of a transparent conductive film is formed on a polymer film as a substrate, and this electrode is used as an anode, and a light emitting layer made of an organic compound is provided between the electrode and an opposing cathode. There is disclosed a flexible organic EL device obtained by providing a single layer or a plurality of layers. This conventionally known organic EL element achieved high luminous efficiency by reducing the number of protrusions on the ITO of the polymer film substrate. Also, [Nature
re) Vol. 357, p. 477 (1992)], a poly (2-methoxy, luminous polymer) is formed on a polyester film formed by using polyaniline as a transparent conductive film.
A solution of 5- (2′-ethyl-hexoxy) -1,4-phenylenevinylene (hereinafter sometimes referred to as MEH-PPV) is applied by a spinner, and then a calcium cathode is evaporated under vacuum to obtain a flexible organic material. EL devices are reported.

[0004] However, many organic electroluminescent devices reported so far have a drawback that they are easily broken and have poor impact resistance because glass is used as a substrate in the production thereof.

Also, a method for manufacturing a flexible organic EL device manufactured by vapor deposition using an organic compound which is a low molecular dye described in the above-mentioned prior art document as a light emitting material, a light emitting polymer ME
A method of manufacturing a flexible organic EL element, which is formed and formed by a spinner coating method using H-PPV as a light-emitting material, requires a high manufacturing cost to form a film on a large-area polymer film. However, it is a disadvantageous process for industrialization such that the characteristics of the element are not stable due to technical difficulty.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to use a flexible polymer film as a substrate and to use a polymer fluorescent substance without impairing the characteristics of high brightness, high luminous efficiency and low drive voltage. Another object of the present invention is to provide a manufacturing method capable of industrially mass-producing a large-area organic electroluminescence element at low cost.

[0007]

In view of such circumstances, the present inventors have intensively studied a method of manufacturing an organic EL device using a polymer phosphor as a light emitting layer and a polymer film as a substrate. As a result, by continuously forming a light emitting layer containing a polyarylenevinylene polymer fluorescent substance, a flexible organic EL device can be obtained stably, and a large area light emitting layer can be easily manufactured. Therefore, they have found that a large-area organic EL element can be obtained by an inexpensive process, and have reached the present invention.

That is, the present invention relates to [1] a method for producing an organic electroluminescent device having at least a light-emitting layer between a transparent or semi-transparent anode and a cathode showing conductivity formed on the surface of a polymer film; The repeating unit represented by the following formula (1) is replaced with 5
The present invention relates to a method for producing an organic electroluminescent device, comprising a step of continuously forming a light emitting layer containing a polymer light emitting material containing 0 mol% or more and having a number average molecular weight in terms of polystyrene of 10 ³ to 10 ^7. .

-Ar-CR = CR'- (1) [where Ar has 4 carbon atoms participating in a conjugated bond.
An arylene group or a heterocyclic compound group consisting of at least 20 and at most 20. R and R ′ each independently represent a group selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heterocyclic compound having 4 to 20 carbon atoms, and a cyano group. . Further, the present invention provides [2] a method for producing an organic electroluminescent device having at least a light-emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film; ] A method of manufacturing an organic electroluminescent device, comprising the steps of continuously forming a light-emitting layer containing a polymer light-emitting material and forming a cathode in this order.

The present invention also provides [3] a method for producing an organic electroluminescent device having at least a light emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film; A step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent or translucent anode showing conductivity on the surface,
[1] A method for manufacturing an organic electroluminescent device, comprising a step of continuously forming a light-emitting layer containing a polymer light-emitting body according to [1] and a step of forming a cathode in this order of time. The present invention also provides [4] a method for producing an organic electroluminescent element having at least a light-emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film; A step of continuously forming a light-emitting layer containing the polymer light-emitting body according to the description,
The present invention relates to a method for manufacturing an organic electroluminescence device having a step of continuously forming an electron transport layer and a step of forming a cathode in this order. Further, the present invention provides [5] a method for producing an organic electroluminescent device having at least a light-emitting layer between a transparent or translucent anode and a cathode exhibiting conductivity formed on the surface of a polymer film; A step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent or translucent anode shown on the surface, continuously forming a light emitting layer containing the polymer light emitting body according to [1]. The present invention relates to a method for manufacturing an organic electroluminescence element, which includes a step of forming a film, a step of continuously forming an electron transport layer, and a step of forming a cathode in this order.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an organic EL device according to the present invention will be described in detail. Examples of the organic EL device obtained by the present invention include those having at least a light-emitting layer between a transparent or translucent anode or cathode having conductivity formed on the surface of a polymer film. The polymer film is used as a substrate in an organic EL device. The light-emitting layer contains a polymer light-emitting material containing the repeating unit represented by the formula (1) in an amount of 50 mol% or more of all the repeating units and having a polystyrene equivalent number average molecular weight of 10 ³ to 10 ^7. It is characterized by. Organic EL of the present invention
The method for manufacturing an element includes a step of continuously forming a light-emitting layer containing the polymer light-emitting body (Invention [1]). Further, the method for producing an organic EL device of the present invention comprises:
(1) The step of continuously forming a light-emitting layer containing a polymer light-emitting material according to (1) and the step of forming a cathode are sequentially performed in this order (Invention [2]). That is, the method is characterized in that a step of continuously forming the light emitting layer and a step of forming the cathode are chronologically provided in this order.

Further, the organic EL device obtained by the present invention includes at least a hole transport layer and a light emitting layer between a conductive transparent or translucent anode and a cathode formed on the surface of a polymer film. And the like. The method for producing an organic EL device of the present invention comprises a step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent or translucent anode exhibiting conductivity, [1] A step of continuously forming a light emitting layer containing the polymer light emitting body described above and a step of forming a cathode are provided in this order (invention [3]). At this time, it is preferable that the hole transport layer is adjacent to the light emitting layer. Further, as the organic EL device obtained according to the present invention, an organic EL device having at least a light emitting layer and an electron transport layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film. No. The method for producing an organic EL device of the present invention includes a step of continuously forming a light-emitting layer containing the polymer light-emitting material according to [1], a step of continuously forming an electron transport layer,
And a step of forming a cathode film in this order of time (Invention [4]). At this time, the electron transporting layer is preferably adjacent to the light emitting layer.

Further, the organic EL device obtained according to the present invention includes at least a hole transport layer and a light emitting layer between a transparent or translucent conductive anode formed on the surface of a polymer film and a cathode. And those having an electron transport layer. The method for producing an organic EL device of the present invention comprises a step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent or translucent anode exhibiting conductivity, [1] A step of continuously forming a light-emitting layer containing the polymer light-emitting body described above, a step of continuously forming an electron transport layer, and a step of forming a cathode. [5]).

Further, in any of the above cases, the method for forming the polymer light emitting layer includes a method of continuously forming a film by coating using a melt, solution or mixture of the material of the light emitting layer. Is preferred. In the inventions [3] to [5], it is preferable that a polymer film having a transparent or translucent anode having conductivity on the surface is supplied by a roll. In the invention [3] or [5],
It is preferable that the step of continuously forming the hole transport layer from the solution and the step of coating the polymer light emitting layer from the solution are continuous. In any of the above cases, a long polymer film having a transparent or translucent electrode showing conductivity on the surface is supplied by a roll, and forms a layer covering a part of the transparent or translucent electrode. It is preferable to have a step of performing

In the present invention, the method for continuously coating the polymer light-emitting layer from a solution may be any method capable of continuously forming a uniform thin film. Examples of the method include microgravure coating, gravure coating, and bar coating. A method selected from the group consisting of a coating method, a roll coating method, a wire bar coating method, a dip coating method, a screen printing method, a flexographic printing method and an offset printing method is preferred.

The thickness of the light emitting layer is preferably 1 nm.
１1 μm, more preferably 2 nm to 500 nm. In order to increase the light emission efficiency by increasing the current density, the thickness is preferably in the range of 5 to 200 nm. In the case where the light-emitting layer is thinned by a coating method, in order to remove the solvent, after forming the light-emitting layer, under reduced pressure or an inert atmosphere,
Preferably from 30 to 300 ° C., more preferably from 60 to 3 ° C.
It is desirable to heat and dry at a temperature of 00 ° C.

In the present invention, the method of continuously coating the hole transport layer and the electron transport layer from a solution also includes the method of continuously coating the light emitting layer from a solution.
Further, one or both of an electron transporting compound and a hole transporting compound may be used in the light emitting layer at the same time. These may be used alone or as a mixture of two or more. 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 luminescent material. Also,
Microgravure coating method after mixing and dispersing the polymer compound and the charge transport material in a solution state or a molten state,
A gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a screen printing method, a flexographic printing method, and an offset printing method can be used. As the polymer compound 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. Alternatively, a film may be formed by a vacuum deposition method from a powder state.

The thickness of the hole transport layer is required to be at least such that pinholes do not occur. However, if the thickness is too large, the resistance of the device increases and a high drive voltage is required, which is not preferable. Therefore, the thickness of the hole transport layer is preferably 1 nm to 1 μm, more preferably 2 nm to 500 n.
m, particularly preferably 5 to 200 nm.

The thickness of the electron transport layer is required to be at least such that no pinholes are generated. However, if the thickness is too large, the resistance of the device increases, and a high drive voltage is required, which is not preferable. Therefore, the thickness of the electron transport layer is preferably 1 nm to 1 μm, more preferably 2 nm to 500 μm.
nm, particularly preferably 5 to 200 nm.

An insulating layer may be provided before or after forming these organic layers. Examples of the material of the insulating layer include light-curing resins, thermosetting resins, organic materials such as polycarbonate and polyethersulfone, and inorganic materials such as Al ₂ O ₃ and SiO ₂ , which need to be formed during continuous coating. In some cases, a photocurable resin or a thermosetting resin that can be formed by coating and curing in a short time is more preferable. Further, the present invention includes a single light emitting layer and a charge transporting layer and a combination of a plurality of layers. Further, the insulating layer and the hole transport layer may be continuously formed.

As the coating method in the present invention, the microgravure coating method, the gravure coating method, and the flexographic printing method are more preferable, and the microgravure coating method and the gravure coating method are particularly preferable.
Microgravure coating is most preferred. Coating by a microgravure coating method or a gravure coating method is preferable because a large-area polymer film can be coated in a short time, and as a result, a low-cost manufacturing method becomes possible. Further, according to the coating method, a thin film having a thickness of 1 μm or less can be formed with high accuracy, so that a coating method suitable for a method of manufacturing an organic electroluminescence element which requires precise control of the coating film thickness is required. It is a construction method.

The method for controlling the coating thickness of the organic layer is to control the depth of the coating roll when coating the solution on the polymer film, and to control the organic material used for the polymer light emitting material and the charge transport layer. It is performed by controlling the amount of the solution, or by controlling the concentration of the organic light emitting material or the organic material used for the charge transport layer. The depth of the coating roll is preferably 5 to 300 μm,
5-200 μm is more preferable, and 5-150 μm is particularly preferable. The solution concentration of the organic material used for the polymer light emitting layer and the charge transport layer is preferably 0.1 to 20% by weight, and 0.1 to 20% by weight.
1-5% by weight is more preferred.

Next, the solvent used for coating will be described. Examples of good solvents for the polymeric fluorescent substance include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like, and preferably methylene chloride and toluene. When laminated on the hole transport layer, it is preferable to dissolve the polymeric fluorescent substance with a solvent having low solubility of the hole transport organic material. In the case where an electron transporting layer is laminated on the light emitting layer formed of the polymeric fluorescent substance, the solvent for dissolving the electron transporting organic material preferably has low solubility of the polymeric fluorescent substance. In addition, when a previously applied layer can be insolubilized by a heat or light crosslinking method or a method of converting a soluble intermediate into an insoluble polymer by heat or light after coating, the layer is more easily laminated. be able to.

Next, members used in the method for manufacturing an organic EL device of the present invention will be described. In the present invention, the polymer material used for the polymer film as the substrate is not particularly limited as long as the film can be formed,
A polymer material having high transparency, relatively high solvent resistance and relatively high heat resistance is preferable. Polymer materials satisfying such conditions include polyether sulfone (PES), polyethylene terephthalate (PET), and polycarbonate (P
C), polyether ether ketone (PEEK), polyvinyl fluoride (PFV), polyacrylate (PA),
Polypropylene (PP), polyethylene (PE), amorphous polyolefin, or a fluorine-based resin;
Polyether sulfone (PES), polyethylene terephthalate (PET), polycarbonate (PC), and polyacrylate (PA) are preferred. In order to increase flexibility, films obtained from these polymer materials are preferably as thin as possible as long as mechanical strength is maintained. The thickness of the polymer film is preferably 1 μm or more.
It is 1 mm, more preferably 2 μm to 1000 μm, particularly preferably 10 μm to 200 μm. A gas barrier organic or inorganic material film may be laminated on the polymer film.

In the present invention, as a material of the anode formed on the surface of the polymer film, a conductive metal oxide film, a translucent metal thin film or the like is used. Specifically, a film formed using a conductive glass made of indium tin oxide (ITO), ZnO, tin oxide (SnO ₂ ), or the like, or gold, platinum, silver, copper, or the like is used. tin oxide (ITO), ZnO, tin oxide (SnO ₂₎ is preferred. Examples of the manufacturing method include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Further, an organic transparent conductive film such as polyaniline may be used as the anode.

The polymeric fluorescent substance contained in the light emitting layer of the organic EL device according to the present invention is polyarylene vinylene or a derivative thereof, and contains the repeating unit represented by the above formula (1) in an amount of 50 mol% or more of all the repeating units. It is a polymer. Although it depends on the structure of the repeating unit, it is preferable that the repeating unit represented by the formula (1) accounts for 70% or more of all the repeating units. The polymeric fluorescent substance can be obtained by using a divalent aromatic compound group or a derivative thereof, a divalent heterocyclic compound group or a derivative thereof, or a combination thereof as a repeating unit other than the repeating unit represented by the formula (1). May be included. Further, the repeating unit represented by the formula (1) or another repeating unit may be linked by a non-conjugated unit having an ether group, an ester group, an amide group, an imide group, or the like, A non-conjugated moiety may be included.

In the polymeric fluorescent substance of the present invention, Ar in the formula (1) is an arylene group or a heterocyclic compound group having from 4 to 20 carbon atoms participating in a conjugate bond. And a divalent aromatic compound group or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, or a group obtained by combining them.

[0027]

Embedded image (R _{1 to} R ₉₂ each independently represent hydrogen, carbon number 1 to 2
0 alkyl, alkoxy and alkylthio groups;
An aryl group and an aryloxy group having 6 to 18 carbon atoms;
And a group selected from the group consisting of heterocyclic compound groups having 4 to 14 carbon atoms. )

Of these, phenylene, substituted phenylene, biphenylene, substituted biphenylene, naphthalenediyl, substituted naphthalenediyl, anthracene-9,10-diyl, substituted anthracene-9,10
-Diyl, pyridine-2,5-diyl, substituted pyridine-2,5-diyl, thienylene or substituted thienylene are preferred. More preferably, a phenylene group,
Biphenylene group, naphthalenediyl group, pyridine-2,
It is a 5-diyl group or a thienylene group.

R and R 'in the formula (1) are hydrogen or cyano
When the case of a substituent other than is described,
Examples of the alkyl group 20 include a methyl group, an ethyl group,
Pill, butyl, pentyl, hexyl, heptyl
Group, octyl group, decyl group, lauryl group, etc.
Methyl, ethyl, pentyl, hexyl,
A butyl group and an octyl group are preferred. As an aryl group
Is a phenyl group, 4-C₁~ C₁₂Alkoxyphenyl group
(C ₁~ C₁₂Indicates that the number of carbon atoms is 1 to 12. Less than
The same applies to the bottom. ), 4-C ₁~ C₁₂Alkylphenyl
Group, 1-naphthyl group, 2-naphthyl group and the like.
You.

From the viewpoint of solvent solubility, Ar of the formula (1)
Is selected from the group consisting of one or more alkyl groups having 4 to 20 carbon atoms, alkoxy groups and alkylthio groups, aryl groups and aryloxy groups having 6 to 18 carbon atoms, and heterocyclic compound groups having 4 to 14 carbon atoms. It is preferred that the compound has a group.

The following are examples of these substituents. 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 decyloxy group, and a laurylthio 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 alkoxyphenyl group, 4-C _{1 ~C 12} alkyl phenyl group, 1-naphthyl group, 2-naphthyl groups. Examples of the aryloxy group include a phenoxy group. Examples of the heterocyclic compound group include a 2-thienyl group, a 2-pyrrolyl group, a 2-furyl group, a 2-, 3- or 4-pyridyl group, and the like. The number of these substituents varies depending on the molecular weight of the polymeric fluorescent substance and the structure of the repeating unit, but from the viewpoint of obtaining a polymeric fluorescent substance having high solubility, these substituents are one or more per 600 molecular weight. Is preferred. The method for synthesizing the polymeric fluorescent substance used in the present invention is not particularly limited.
The method described in JP-A No. 2355 is cited.

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, such as a random copolymer having a block property. It may be united. 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.
In addition, since light emission from a thin film is used, a polymer fluorescent substance having fluorescence in a solid state is preferably used.

As a good solvent for the polymeric fluorescent substance,
Examples include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like.
Although it depends on the structure and molecular weight of the polymeric fluorescent substance, it can be generally dissolved in these solvents in an amount of 0.1% by weight or more.

The polymeric fluorescent substance of the present invention has a molecular weight of 10 ³ to 10 ⁷ 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 4 to 10,000, more preferably from 5 to 3000, and particularly preferably from 10 to 2000, from the viewpoint of film formability.

When these polymer fluorescent materials are used as a light emitting material of an organic EL device, their purity affects the light emitting characteristics. Therefore, after synthesis, purification treatment such as reprecipitation purification, fractionation by chromatography, etc., may be required. preferable.

When a film is formed from a solution by using these organic solvent-soluble polymeric phosphors when preparing an organic EL device, 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.

In the present invention, known light-emitting materials that can be used together with the polymeric fluorescent substance are not particularly limited. Examples thereof include naphthalene derivatives, anthracene or its derivatives, perylene or its derivatives, polymethine, xanthene, coumarin, and cyanine. Pigments such as system, 8
-A metal complex of hydroxyquinoline or a derivative thereof,
Aromatic amine, tetraphenylcyclopentadiene or a derivative thereof, or tetraphenylbutadiene or a derivative thereof can be used. Specifically, for example, JP-A-57-51781 and JP-A-59-1
Known ones such as those described in Japanese Patent No. 94393 can be used.

Further, for example, a light emitting material described below other than the polymeric fluorescent substance may be mixed and used in the light emitting layer. Further, a layer in which the polymeric fluorescent substance and / or the charge transporting material is dispersed in a polymeric compound may be used.

In the present invention, known charge transporting materials, that is, electron transporting materials or hole transporting materials used together with the polymeric fluorescent substance can be used, and pyrazoline derivatives and arylamine derivatives can be used as the hole transporting materials. , Stilbene derivatives, triphenyldiamine derivatives, and the like. Examples of the electron transporting material include oxadiazole derivatives, anthraquinodimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, and tetracyanoanthraquino. Examples thereof include dimethane or a derivative thereof, a fluorenone derivative, diphenyldicyanoethylene or a derivative thereof, a diphenoquinone derivative, and a metal complex of 8-hydroxyquinoline or a derivative thereof. Specifically, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, and 2-209988
JP, 3-37992, and 3-152184
And the like described in Japanese Patent Application Laid-Open Publication No. H10-26095.

Among them, a triphenyldiamine derivative is used as a hole transporting material used in the light emitting layer, an oxadiazole derivative is used as an electron transporting material used in the light emitting layer,
Benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, or a metal complex of 8-hydroxyquinoline or a derivative thereof is preferable. Particularly, as a hole transporting material, 4,4′-bis (N (3-methylphenyl) -N- Phenylamino) biphenyl, as an electron transporting material, 2- (4-biphenylyl) -5- (4-t-
(Butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are preferred. Among them, one or both of the electron transporting compound and the hole transporting compound may be used simultaneously. These may be used alone or as a mixture of two or more.

In the present invention, as the hole transporting material used for the hole transporting layer, known materials can be used, and low molecular weight pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, etc. Poly (N-vinylcarbazole), polyaniline and its derivatives, polythiophene and its derivatives, poly (p-
Phenylenevinylene) and its derivatives, poly (2,5
-Thienylenevinylene) and its derivatives can be used. Although a low-molecular-weight hole transport material may be used alone,
It may be used as a mixture with a transparent polymer compound. Examples of the polymer compound used include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane. As a solvent for dissolving the hole transport layer in the case of applying using a solution, it is preferable that the solvent has low solubility with respect to the polymeric fluorescent substance of the light emitting layer.

As the electron transporting material used together with the polymeric fluorescent substance of the present invention, known materials can be used. Examples of the electron transporting material include oxadiazole derivatives, anthraquinodimethane or its derivatives, benzoquinone or its derivatives. , Naphthoquinone or its derivative, anthraquinone or its derivative, tetracyanoanthraquinodimethane or its derivative, fluorenone derivative,
Examples include diphenyldicyanoethylene or a derivative thereof, a diphenoquinone derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof. Specifically, JP-A-63-70257 and JP-A-63-175860
JP-A-2-135359, JP-A-2-13536
No. 1, No. 2-209988, No. 3-37992, and No. 3-152184 are exemplified.

In the present invention, the electron transporting material used for the electron transporting layer is preferably an oxadiazole derivative, benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, or a metal complex of 8-hydroxyquinoline or a derivative thereof. As the material, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are preferable.

A microgravure coating method, a gravure coating method, a bar coating method after mixing and dispersing the polymer compound and the charge transport material in a solution state or a molten state,
Roll coating, wire bar coating, dip coating, screen printing, flexographic printing, and offset printing can be used. As the polymer compound to be mixed, those that do not extremely inhibit charge transport are preferable,
In addition, those that do not have strong absorption for visible light are preferably used. Examples of the polymer compound 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. ,
Examples thereof include polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

Further, in order to form a light emitting pattern or to make etching for forming an electrode unnecessary,
It is preferable to provide an insulating layer before or after forming these organic layers. Examples of the material of the insulating layer include light-curing resins, thermosetting resins, organic materials such as polycarbonate and polyethersulfone, and inorganic materials such as Al ₂ O ₃ and SiO ₂ , which need to be formed during continuous coating. In some cases, a photocurable resin or a thermosetting resin that can be formed by coating and curing in a short time is more preferable.

Next, as the material of the cathode used in the present invention, a material having a small ionization energy is preferable. For example, aluminum, indium, magnesium, calcium, lithium, magnesium-silver alloy, magnesium-indium alloy, lithium-aluminum alloy, lithium-silver alloy, lithium-indium alloy, calcium-aluminum alloy, graphite thin film and the like are used. As a method for manufacturing the cathode, a vacuum evaporation method, a sputtering method, a lamination method of thermocompression bonding a metal thin film, or the like is used. After the cathode is formed, a protective layer for protecting the organic EL device may be provided.

[0048]

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> 2,5-dioctyloxy-
p-Xylylene dibromide was reacted with triphenylphosphine in N, N-dimethylformamide solvent to synthesize a phosphonium salt. 47. The obtained phosphonium salt
75 parts by weight and 6.7 parts by weight of terephthalaldehyde were dissolved in ethyl alcohol. An ethyl alcohol solution containing 5.8 parts by weight of lithium ethoxide was added dropwise to an ethyl alcohol solution of a phosphonium salt and dialdehyde, and polymerized at room temperature for 3 hours. After leaving overnight at room temperature,
The precipitate was separated by filtration, washed with ethyl alcohol, dissolved in chloroform, and ethanol was added thereto to reprecipitate. This was dried under reduced pressure to obtain 8.0 parts by weight of a polymer. This is called polymeric fluorescent substance 1. The repeating units of polymeric fluorescent substance 1 calculated from the charged ratio of the monomers and the molar ratios thereof are shown below.

Embedded image The molar ratio of the two repeating units is 1: 1 and the two repeating units are linked alternately. The polymeric fluorescent substance 1
The number average molecular weight in terms of polystyrene is 1.0 × 10 ⁴
Met. The structure of the polymeric fluorescent substance 1 was confirmed by an infrared absorption spectrum and NMR.

<Preparation and evaluation of element>
Polymer fluorescent substance 1 was applied to a polyethylene terephthalate film substrate with an ITO film having a length of 50 m, a thickness of 125 μm, and a surface resistivity of 300 Ω (trade name TCF, KB300N-125, transparent conductive film, manufactured by Oike Industry Co., Ltd.). A 0 wt% toluene solution was formed to a thickness of 50 nm over a width of 300 mm and a length of 30 m by a microgravure method using a multi-purpose coater (manufactured by Yasui Seiki Co., Ltd.). After the film formation, the film thickness distribution in the film coating direction and the film width direction was within ± 5%.

[0050] Further, 0.1 after this and the coated film was dried under reduced pressure for 1 hour 80 ° C., as the electron transporting layer, tris (8-quinolinol) aluminum _(hereinafter sometimes referred to as Alq _3.) 35 nm at a rate of 0.2 nm / s
Evaporated. On top of this, a lithium-aluminum alloy
An organic EL device was prepared by vapor deposition at 0 nm. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less. When a voltage of 8 V was applied to this element, the current density was 24.3.
A current of mA / cm ² flows, and a luminance of 212.4 cd / m ²
Of yellow-green EL was observed. The luminous efficiency at this time was 0.88 cd / A (0.34 lm / W), and even when the substrate was wound around a rod having a diameter of 2 cm, almost no non-light-emitting portion (dark spot) was generated. Further, the luminance after storage in a nitrogen atmosphere for one day was almost proportional to the current density, and did not decrease much from the initial efficiency. In addition, the EL peak wavelength was 540 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of the polymer fluorescent substance 1, and EL emission from the polymer fluorescent substance 1 was confirmed.

Example 2 <Preparation and evaluation of element> A width of 330 mm, a length of 50 m,
100μm thick, surface resistivity 70Ω (Sumilite FST, transparent conductive film, manufactured by Sumitomo Bakelite Co., Ltd.)
1349), a 1.0 wt% methylene chloride solution of polyvinyl carbazole was first applied to the polyethersulfone film substrate with an ITO film by a microgravure method using a multi-purpose coater (manufactured by Yasui Seiki Co., Ltd.), and then continuously. A 1.0 wt% toluene solution of polymeric fluorescent substance 1 was applied. As a result, a polyethersulfone film substrate with an ITO film was formed to have a thickness of 50 nm over a width of 300 mm and a length of 30 m, and further formed thereon a polymeric fluorescent substance 1 having a 50 nm-thick organic layer having a two-layer structure. Was done. After the film formation, the film thickness distribution in the film coating direction and the film width direction was within ± 5%.

Further, the coated film was dried under reduced pressure at 80 ° C. for 1 hour, and then tris (8-quinolinol) aluminum (Alq3) was used as an electron transporting layer in the range of 0.1 to 0.1.
35 nm was deposited at a rate of 2 nm / s. On top of that, a 40 nm thick lithium-aluminum alloy is deposited to
An element was manufactured. The degree of vacuum during evaporation is 8 × 10
^-6 Torr or less. When a voltage of 8 V was applied to this device, a current having a current density of 1.76 mA / cm ² flowed and yellow-green EL emission with a luminance of 115.4 cd / m ² was observed. The luminous efficiency at this time is 6.5 cd / A (2.
5 lm / W), and even when the substrate was wound around a rod having a diameter of 2 cm, almost no non-light-emitting portion (dark spot) was generated. Further, the luminance after storage in a nitrogen atmosphere for one day was almost proportional to the current density, and did not decrease much from the initial efficiency. In addition, the EL peak wavelength was 540 nm, which substantially coincided with the fluorescence peak wavelength of the thin film of the polymer fluorescent substance 1, and EL emission from the polymer fluorescent substance 1 was confirmed.

Comparative Example 1 <Preparation and evaluation of device> A polyethylene terephthalate film substrate with an ITO film having a thickness of 125 μm and a surface resistivity of 300Ω (transparent conductive film tetraite TCF, KB300N-125 manufactured by Oike Industry Co., Ltd.) was A4 size. The film was cut into a film having a thickness of 50 nm using a 1.0 wt% toluene solution of the polymeric fluorescent substance 1 and using a bar coater. After the film formation, the area where the coating could be performed uniformly with the naked eye was about 15 cm square. The film thickness distribution in the film coating direction and the film width direction in the region where the coating was performed uniformly was ± 5% or less. Further, after drying the coated film at 80 ° C. for 1 hour under reduced pressure, tris (8-quinolinol) aluminum (Alq3) was added as an electron transporting layer to a thickness of 0.1%.
35 nm was deposited at a rate of 1 to 0.2 nm / s. A 40 nm thick lithium-aluminum alloy was deposited thereon to produce an organic EL device. The degree of vacuum at the time of vapor deposition was 8 × 10 ⁻⁶ Torr or less. A voltage of 8 V is applied to this element.
Was applied, a current having a current density of 23.5 mA / cm ² flowed, and yellow-green EL emission with a luminance of 202.6 cd / m ² was observed. The luminous efficiency at this time is 0.81 cd /
A (0.31 lm / W), and even when the substrate was wound around a rod having a diameter of 2 cm, almost no non-light-emitting portion (dark spot) was generated. Further, the luminance after storage in a nitrogen atmosphere for one day was almost proportional to the current density, and did not decrease much from the initial efficiency. The EL peak wavelength is 540 nm.
As a result, the fluorescence peak wavelength of the thin film of the polymeric fluorescent substance 1 was substantially the same, and EL emission from the polymeric fluorescent substance 1 was confirmed.

As described above, by the continuous coating in Examples 1 and 2, polyethylene terephthalate (PE)
T) or polyethersulfone (PES) as a base material can easily and continuously apply a uniform light-emitting layer film.
In addition, this organic EL device has a fertility that cannot be obtained with a device using a glass substrate, and a uniform film can be easily obtained over a wide area as compared with the batch-type coating method described in the comparative example. Therefore, it is a process suitable for industrialization, such as stable element characteristics and low manufacturing cost.

[0055]

According to the method for manufacturing an organic electroluminescence device of the present invention, since the light emitting layer is formed by continuous coating, coating of a large area can be performed in a short time and industrially low cost. Process. Further, the organic electroluminescent device obtained by the present invention has a high impact resistance because the substrate is a flexible polymer film, and even if the organic EL device is bent or twisted while emitting light,
Its EL characteristics, namely high brightness, high luminous efficiency, long life,
The characteristic of a low driving voltage does not decrease. Therefore, the organic EL element can be preferably used as a device having a curved or planar light source as a backlight, a flat panel display, or the like.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus used in a method for manufacturing an organic electroluminescence element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hole transport material solution 2 ... Light emitting material solution 3 ... Microgravure coater 4 ... Polymer film with ITO 5 ... Dryer 6 ... Bobbin 7 ... Roll 8 ···container

Claims (10)

[Claims] 1. A conductive film formed on a surface of a polymer film.
Indicating at least between a transparent or translucent anode and cathode
Manufacture of an organic electroluminescence device having a light emitting layer
In the manufacturing method, a repeating unit represented by the following formula (1)
Is contained in an amount of at least 50 mol% of all repeating units,
Number average molecular weight of 10^Three-10 ⁷Polymer
Having a step of continuously forming a light emitting layer including a light body
Of organic electroluminescence device characterized by the following
Method. (1) wherein Ar has 4 carbon atoms involved in a conjugated bond
Arylene group or heterocyclization consisting of at least 20 and at most 20
It is a compound group. R and R 'each independently represent hydrogen, carbon
An alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms
Group, a heterocyclic compound having 4 to 20 carbon atoms and a cyano group
A group selected from the group consisting of: ] 2. A method for producing an organic electroluminescence device having at least a light emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film. A method for manufacturing an organic electroluminescent device, comprising: a step of continuously forming a light emitting layer including a light emitting body; and a step of forming a cathode. 3. A method for producing an organic electroluminescent device having at least a light-emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film. 2. A step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent anode on the surface, and a step of continuously forming a light emitting layer containing the polymer light emitting body according to claim 1. And a step of forming a cathode film in this order of time. 4. A method for producing an organic electroluminescent device having at least a light-emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film. Manufacturing an organic electroluminescent device, comprising a step of continuously forming a light emitting layer including a light emitting body, a step of continuously forming an electron transport layer, and a step of forming a cathode in this order of time. Method. 5. A method for producing an organic electroluminescent device having at least a light emitting layer between a transparent or translucent anode and a cathode showing conductivity formed on the surface of a polymer film. 2. A step of continuously forming a hole transport layer on the anode side of a polymer film having a transparent anode on the surface, and a step of continuously forming a light emitting layer containing the polymer light emitting body according to claim 1. And a step of continuously forming an electron transport layer and a step of forming a cathode in this order. 6. The method for producing an organic electroluminescent device according to claim 1, wherein the polymer light emitting layer is applied from a melt or a solution. 7. The method for producing an organic electroluminescent device according to claim 3, wherein a polymer film having a transparent or translucent anode having conductivity on its surface is supplied by a roll. . 8. The method according to claim 3, wherein the step of continuously forming the hole transport layer from the solution and the step of coating the polymer light emitting layer from the solution are continuous. A method for manufacturing an organic electroluminescence element. 9. A process in which a long polymer film having a transparent or translucent electrode showing conductivity on its surface is supplied by a roll, and a step of forming a layer covering a part of the transparent or translucent electrode is provided. The method for manufacturing an organic electroluminescence device according to claim 1, wherein: 10. A coating selected from the group consisting of microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, screen printing, flexographic printing, and offset printing. The method for producing an organic electroluminescent device according to any one of claims 1 to 9, wherein the polymer light emitting layer is continuously coated from a solution by a method.