WO2011105141A1

WO2011105141A1 - Organic electroluminescent component and method of manufacturing same

Info

Publication number: WO2011105141A1
Application number: PCT/JP2011/051079
Authority: WO
Inventors: 雄史小野; 邦雅檜山
Original assignee: コニカミノルタホールディングス株式会社
Priority date: 2010-02-23
Filing date: 2011-01-21
Publication date: 2011-09-01
Also published as: JPWO2011105141A1; JP5960047B2

Abstract

Disclosed is a flexible organic electroluminescent component with high luminous efficiency, long life and high-temperature storage stability as well as excellent operational stability when folded. The organic electroluminescent component is comprised of a first electrode, an organic compound layer containing at least one layer of light-emitting layer composed of organic compounds, a second electrode, and a flexible sealing member, disposed above a flexible supporting substrate in that order. The organic electroluminescent component is adhesively sealed and possesses a thermally conductive layer and a sealing adhesive disposed in that order between the second electrode and the flexible sealing member. The second electrode is silver or a silver alloy where silver is the principal constituent.

Description

Organic electroluminescence device and method for manufacturing the same

The present invention relates to an organic electroluminescence device and a method for producing the same, and more specifically, a flexible organic electroluminescence device having high luminous efficiency, long life, excellent storage stability at high temperature, and excellent driving stability during bending, and It relates to the manufacturing method.

Demand for surface light emitting devices with low power consumption and small volume has increased, and electroluminescent devices (hereinafter abbreviated as “EL devices”) are attracting attention as one of such surface light emitting devices. Such EL elements are roughly classified into inorganic electroluminescent elements (hereinafter referred to as “inorganic EL elements”) and organic electroluminescent elements (hereinafter referred to as “organic EL elements”) depending on the materials used.

Here, the inorganic EL element generally applies a high electric field to the light emitting portion, accelerates electrons in the high electric field to collide with the light emission center, thereby exciting the light emission center to emit light. On the other hand, the organic EL element injects electrons and holes from the electron injection electrode and the hole injection electrode, respectively, into the light emitting layer, and combines the injected electrons and holes in the light emitting layer. Light is emitted when the organic material returns to the ground state from the excited state in the excited state, and there is an advantage that it can be driven at a lower voltage than the inorganic EL element. Taking advantage of the fact that it emits light on its surface, it is expected as a thin display and lighting application. In particular, development of flexible organic EL elements suitable for mass production is expected.

Organic EL elements are weak against moisture and oxygen and are generally sealed for the purpose of preventing them from moisture and oxygen. Sealing is classified into casing type sealing (can sealing) and close contact type sealing (solid sealing), but solid sealing is preferable from the viewpoint of thinning. Moreover, when producing a flexible organic EL element, since sealing is also required for the sealing member, solid sealing is preferable.

固体 Solid sealing is gaining sufficient sealing performance due to technological advances. However, while can sealing makes it easy to put a desiccant, solid sealing makes it difficult. Furthermore, in the case of solid sealing, since there is moisture brought in by the sealing adhesive, the actual situation is that the influence of moisture is greater than that in can sealing. In particular, the difference in sealing performance becomes large during high temperature storage or high temperature high humidity storage.

In order to increase the efficiency of the organic EL panel, the reflectivity of the reflective electrode is better. In particular, when a light extraction member such as a light diffusion sheet or a microlens sheet is used, if the reflectance of the reflective electrode is high, it is effective for improving the light emission efficiency. A common reflective electrode is aluminum. Silver is an example of a higher reflectivity material than aluminum, but silver is known to be largely affected by deterioration factors such as water, oxygen, or heat and lack stability. In particular, ion migration may occur due to moisture, and silver may diffuse into the organic layer, resulting in a short circuit. Therefore, an organic EL element using silver instead of aluminum is required to have a high level of sealing performance. As stabilization of silver, a method of forming an alloy with another metal and stabilizing it is known. However, in order to obtain a higher reflectance than aluminum, it is necessary to make silver 90 atomic% or more. In that range, deterioration due to water and oxygen is larger than aluminum.

When producing a flexible organic EL device with high luminous efficiency, it is preferable to combine a high reflectance cathode and solid sealing. However, when organic EL elements using silver or a silver alloy mainly composed of silver as a reflective electrode are solid-sealed, the device may be short-circuited or dark spots may be generated due to the residual moisture of the sealing adhesive. There was a problem. In addition, silver or silver-based silver alloys have high thermal conductivity, whereas adhesives used for solid sealing have extremely low thermal conductivity, and heat generated from the organic EL element is not easily released by driving. As a result, the temperature of the organic EL element rises, causing a problem that silver ion migration is accelerated. Further, it has been found that a flexible organic EL element using silver as a reflective electrode has low driving stability during bending.

Patent Document 1 describes that when an active metal such as moisture or oxygen is used as an electrode material, a cap layer that protects the metal is laminated. However, when a flexible substrate is used, driving when bending is performed. It was found that the stability was low.

JP-A-10-261491

The present invention has been made in view of the above problems, and its purpose is to provide a flexible organic electroluminescence device having high luminous efficiency, long life, excellent high-temperature storage stability, and excellent driving stability during bending. Is to provide.

The above object of the present invention is achieved by the following configuration.

1. In the organic electroluminescence element having a first electrode, an organic compound layer including at least one light emitting layer made of an organic compound, a second electrode, and a flexible sealing member in this order on a flexible support substrate, An organic electroluminescence element having a heat conductive layer and a sealing adhesive in this order between two electrodes and the flexible sealing member and sealed tightly, wherein the second electrode is made of silver or silver An organic electroluminescence element characterized by being a silver alloy having a main component.

2. 2. The organic electroluminescence according to 1, wherein a light extraction member is provided between the flexible support substrate and the second electrode or on the opposite side of the flexible support substrate from the first electrode. element.

3. 3. The organic electroluminescence device as described in 1 or 2 above, wherein the sealing adhesive has a water content of 0.01 to 300 ppm.

4. 4. The organic electroluminescence device according to any one of 1 to 3, wherein the heat conductive layer is made of a metal.

5. 5. The organic electroluminescence device according to any one of 1 to 4, wherein the silver content of the second electrode is 90 atomic percent or more.

6. In the manufacturing method of the organic electroluminescent element which has a 1st electrode, the organic compound layer which contains at least 1 light emitting layer which consists of an organic compound, a 2nd electrode, and the flexible sealing member in this order on a flexible support substrate. The organic electroluminescence device is disposed between the second electrode and the flexible sealing member in this order, and a heat conductive layer and a sealing adhesive are arranged in this order, and the sealing adhesive is used for tightly sealing. It is a method, Comprising: The said 2nd electrode is silver or the silver alloy which has silver as a main component, The manufacturing method of the organic electroluminescent element characterized by the above-mentioned.

7. 7. The method for producing an organic electroluminescent element according to 6 above, wherein the moisture content of the sealing adhesive is dried to 300 ppm or less.

According to the present invention, it was possible to provide a flexible organic electroluminescence device having high luminous efficiency, long life, excellent high-temperature storage stability, and excellent driving stability during bending.

A cross-sectional schematic diagram showing a configuration of an organic electroluminescence element having a first electrode, an organic compound layer, a second electrode, a heat conductive layer, a sealing adhesive, and a flexible sealing member in this order on a flexible support substrate. FIG.

As a result of intensive studies on improving luminous efficiency using a silver or silver alloy electrode while satisfying high-temperature storage stability and driving stability in the flexible organic EL element, the present inventors have made a second electrode. By providing a heat conductive layer and a sealing adhesive between the flexible sealing member and the flexible sealing member, it is possible to improve luminous efficiency using silver or silver alloy electrodes while satisfying high temperature storage stability and driving stability As a result, the inventors have found out that the present invention can be achieved.

In this configuration, a heat conductive layer having a high thermal conductivity is laminated on the second electrode, and heat dissipation is promoted, so that the temperature rise of the organic EL element is alleviated and silver diffusion is suppressed. Further, the diffusion of silver is suppressed by the heat conduction layer mitigating the influence of the residual moisture of the sealing adhesive. Furthermore, it has been found that the driving stability at the time of bending is improved by adopting this configuration.

Hereinafter, the details of the mode for carrying out the present invention will be described.

<< Structure of organic electroluminescence element >>
FIG. 1 is a schematic cross-sectional view showing the configuration of the organic EL device of the present invention. The organic EL device of the present invention includes a first electrode 2, an organic compound layer 3 including at least one light emitting layer made of an organic compound, a second electrode 4, a heat conductive layer 5, a sealing, on a flexible support substrate 1. Adhesive 6 and flexible sealing member 7 in this order.

Specific examples of preferred configurations are shown below, but the present invention is not limited thereto.

(I) Flexible support substrate / first electrode / light emitting layer / electron transport layer / second electrode / thermal conductive layer / sealing adhesive / flexible sealing member (ii) flexible support substrate / first 1 electrode / hole transport layer / light emitting layer / electron transport layer / second electrode / thermal conductive layer / sealing adhesive / flexible sealing member (iii) flexible support substrate / first electrode / hole Transport layer / light emitting layer / hole blocking layer / electron transport layer / second electrode / thermal conductive layer / sealing adhesive / flexible sealing member (iv) flexible support substrate / first electrode / hole Transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / second electrode / thermal conductive layer / sealing adhesive / flexible sealing member (v) flexible support substrate / first Electrode / anode buffer layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / second electrode / heat conducting layer / adhesive for sealing / flexible sealing member.

[Flexible support substrate]
The flexible support substrate according to the present invention is not particularly limited as long as it has flexibility, and it may be transparent or opaque.

Examples of the opaque flexible support substrate include metal plates / films such as aluminum and stainless steel, opaque resin substrates, ceramic substrates, and the like.

When extracting light from the flexible support substrate side, the substrate is preferably transparent. Examples of the transparent substrate preferably used include flexible thin film glass and transparent resin film. A particularly preferred substrate is a resin film.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfone , Polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, cycloolefin resin such as Arton (manufactured by JSR) or Appel (manufactured by Mitsui Chemicals), etc. .

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C., measured by a method according to JIS K 7129-1992) It is preferable that the relative humidity (90 ± 2)% RH) is a barrier film of 1 × 10 ⁻³ g / (m ² · 24 h) or less, and further measured by a method according to JIS K 7126-1987. The oxygen permeability is 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, and the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is 1 × 10 ⁻ A high barrier film of ³ g / (m ² · 24 h) or less is preferable.

In order to obtain a high barrier film, the material for forming the barrier film formed on the surface of the resin film may be any material that has a function of suppressing intrusion of water or oxygen that causes panel deterioration. Silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

(Method for forming barrier film)
The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

[First electrode]
As the first electrode (anode) in the present invention, an electrode material made of a metal, an alloy, an electrically conductive compound and a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material capable of forming a transparent conductive film such as IDIXO (In ₂ O ₃ —ZnO) may be used.

For the first electrode, a thin film may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not so high (100 μm As described above, a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used.

When taking out light emission from the first electrode, it is desirable to make the transmittance larger than 10%, and the sheet resistance as the first electrode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

[Organic compound layer]
The organic compound layer in the present invention has a configuration in which functional layers made of various organic compounds, such as a hole injection / transport layer / light emitting layer / electron injection / transport layer, are laminated as necessary. Most simply, it has a structure consisting only of a light emitting layer.

(Hole injection / transport layer)
Examples of organic compound materials used for the hole injection / transport layer include phthalocyanine derivatives, heterocyclic azoles, aromatic tertiary amines, polyvinyl carbazole, polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT: PSS), and the like. A polymer material such as a conductive polymer is used.

(Light emitting layer)
Examples of the light emitting material or host compound used for the light emitting layer include carbazole-based materials such as 4,4′-dicarbazolylbiphenyl and 1,3-dicarbazolylbenzene, (di) azacarbazoles, Examples thereof include low molecular materials typified by pyrene-based materials such as 1,3,5-tripyrenylbenzene, and polymer materials typified by polyphenylene vinylenes, polyfluorenes, polyvinyl carbazoles, and the like. Among these, a low molecular weight material having a molecular weight of 10,000 or less is preferably used as the light emitting material or the host compound.

The light emitting layer may contain about 0.1 to 20% by mass of a dopant compound. Examples of the dopant compound include known fluorescent dyes such as perylene derivatives and pyrene derivatives, and phosphorescent dyes such as tris ( Complex compounds such as ortho-metalated iridium complexes represented by 2-phenylpyridine) iridium, bis (2-phenylpyridine) (acetylacetonato) iridium, bis (2,4-difluorophenylpyridine) (picolinato) iridium, etc. Can be mentioned.

(Electron injection / transport layer)
Examples of the electron injecting / transporting layer material include metal complex compounds such as 8-hydroxyquinolinate lithium and bis (8-hydroxyquinolinato) zinc, and the following nitrogen-containing five-membered ring derivatives. That is, oxazole, thiazole, oxadiazole, thiadiazole or triazole derivatives are preferred. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-thiadiazole, 1,4-bis [2- (5-phenyl) Asiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

As the organic compound material used for these light emitting layers and each functional layer, a material having a polymerization reactive group such as a vinyl group in the molecule is used, and a cross-linked / polymerized film is formed after film formation to form each functional layer. May be.

In addition, an injection layer may be formed between the electrode and the organic layer in order to reduce the drive voltage and improve the light emission luminance as necessary. The injection layer includes a hole injection layer (anode buffer layer) and a cathode buffer layer (electron injection layer).

(Anode buffer layer (hole injection layer))
As the anode buffer layer (hole injection layer), phthalocyanine buffer layer typified by copper phthalocyanine, oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polyaniline (emeraldine), polythiophene, etc. Examples thereof include a polymer buffer layer using molecules.

(Cathode buffer layer (electron injection layer))
The cathode buffer layer (electron injection layer) is a metal buffer layer typified by strontium, aluminum, calcium or magnesium, an alkali metal compound buffer layer typified by lithium fluoride, or an alkaline earth metal typified by magnesium fluoride. Examples thereof include a compound buffer layer and an oxide buffer layer typified by aluminum oxide. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 5 nm, depending on the material. The injection layer may be a single layer or a plurality of layers.

In the organic EL device of the present invention, the injection layer adjacent to the second electrode is preferably a metal buffer layer, more preferably calcium or magnesium, and still more preferably calcium.

In the organic EL device of the present invention, each functional layer may be formed by a vacuum method, a dry method such as a sputtering method, or may be formed by a wet method such as a coating method or a printing method.

[Second electrode]
The second electrode in the present invention is silver or a silver alloy containing silver as a main component, preferably silver or a silver alloy having a silver content of 90 atomic percent or more, and a silver content of 95 atomic percent or more. More preferably, it is an alloy. The second electrode can be formed by a method such as vapor deposition or sputtering.

(Thermal conduction layer)
The heat conductive layer in the present invention is a layer having a heat conductivity larger than that of the sealing adhesive, preferably the heat conductivity is 1 W / (m · K) or more, more preferably 10 W / ( m · K) or more, more preferably 100 W / (m · K) or more. The thermal conductivity of the heat conductive layer in the present invention is preferably 100 W / (m · K) or more higher than the heat conductivity of the sealing adhesive.

The material used for the heat conductive layer according to the present invention is a material containing a metal such as metal, metal oxide, or metal oxide, but is preferably a metal such as aluminum, copper, or gold, more preferably Aluminum.

The thickness of the heat conductive layer according to the present invention is 20 nm to 50 μm, preferably 50 nm to 1 μm, more preferably 100 nm to 500 nm.

The heat conductive layer according to the present invention may be a single layer or a multilayer structure of two or more layers. The second electrode can be formed by a method such as vapor deposition or sputtering.

[Sealant for sealing]
As the sealing adhesive according to the present invention, a thermosetting adhesive, an ultraviolet curable resin, or the like can be used, but preferably a thermosetting adhesive such as an epoxy resin, an acrylic resin, or a silicone resin, more preferably moisture resistant. It is an epoxy thermosetting adhesive resin that is excellent in water resistance and water resistance and has little shrinkage during curing.

The water content of the sealing adhesive according to the present invention is preferably from 0.01 to 300 ppm, more preferably from 0.01 to 200 ppm, and most preferably from 0.01 to 100 ppm.

The moisture content may be measured by any method. For example, a volumetric moisture meter (Karl Fischer), an infrared moisture meter, a microwave transmission moisture meter, a heat-dry weight method, GC / MS, IR, DSC (Differential scanning calorimeter) and TDS (temperature programmed desorption analysis). Further, using a precision moisture meter AVM-3000 (manufactured by Omnitech) or the like, moisture can be measured from a pressure increase caused by evaporation of moisture, and moisture content of a film or solid film can be measured.

In the present invention, the water content of the sealing adhesive can be adjusted by, for example, placing it in a nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 1 ppm or lower and changing the time. Further, it can be dried in a vacuum state of 100 Pa or less while changing the time. Further, the sealing adhesive can be dried only with an adhesive, but can also be placed in advance on a flexible sealing member and dried.

[Flexible sealing member]
Examples of the flexible sealing member include stainless steel, aluminum, magnesium alloy and other metals, polyethylene terephthalate, polycarbonate, polystyrene, nylon, polyvinyl chloride, and the like, and composites thereof, glass and the like. In particular, in the case of a resin film, it is possible to use a laminate of gas barrier layers such as aluminum, aluminum oxide, silicon oxide, and silicon nitride as in the case of the flexible support substrate. The gas barrier layer can be formed by sputtering, vapor deposition or the like on both sides or one side of the flexible sealing member before molding the flexible sealing member, or after sealing, the gas barrier layer can be formed on the both sides or one side of the sealing member by the same method. May be formed. Also in this case, the oxygen permeability is 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is 1 × It is preferably 10 ⁻³ g / (m ² · 24 h) or less.

The flexible sealing member may be a film laminated with a metal foil such as aluminum. As a method for laminating the polymer film on one side of the metal foil, a generally used laminating machine can be used. As the adhesive, polyurethane-based, polyester-based, epoxy-based, acrylic-based adhesives and the like can be used. You may use a hardening | curing agent together as needed. A hot melt lamination method, an extrusion lamination method and a coextrusion lamination method can also be used, but a dry lamination method is preferred.

If the metal foil is formed by sputtering or vapor deposition, or is formed from a fluid electrode material such as a conductive paste, the polymer foil is used as a base material and the metal foil is formed on the substrate. May be.

[Sealing]
When close sealing (solid sealing) is performed, as the flexible sealing member, for example, a 50 μm thick PET (polyethylene terephthalate) laminated with an aluminum foil (30 μm thick) is used. Using this as a flexible sealing member, it is uniformly applied to the aluminum surface using a dispenser, a sealing adhesive is placed in advance, the resin substrate 1 and the sealing member 5 are aligned, and then both are crimped together. (0.1 to 3 MPa), tightly bonded and bonded (adhered) at a temperature of 80 to 180 ° C., and tightly sealed (solid sealed).

Heating or pressure bonding time varies depending on the type, amount, and area of the sealing adhesive, but temporary bonding is performed at a pressure of 0.1 to 3 MPa, and the heat curing time is 5 seconds to 10 minutes at a temperature of 80 to 180 ° C. Select within the range.

It is preferable to use a heated pressure-bonding roll because pressure bonding (temporary bonding) and heating can be performed simultaneously, and internal voids can be eliminated at the same time.

Also, as a method for forming the adhesive layer, a dispenser, a coating method such as roll coating, spin coating, screen printing method, spray coating, or the like can be used depending on the material.

Solid sealing is a form of covering with a cured resin with no space between the flexible sealing member and the organic EL element substrate as described above.

(Light extraction member)
In the present invention, it is preferable to have a light extraction member between the flexible support substrate and the second electrode or on the opposite side of the flexible support substrate from the first electrode.

Examples of the light extraction member used in the present invention include a prism sheet, a lens sheet, and a diffusion sheet. Further, a diffraction grating or a diffusion structure introduced into an interface that causes total reflection or any medium may be used.

Normally, in an organic EL device that emits light from a flexible support substrate, a part of the light emitted from the light emitting layer causes total reflection at the interface between the flexible support substrate and air, and light is lost. Problem occurs. In order to solve this problem, the surface of the flexible support substrate is processed into a prism or lens shape, or the prism sheet, the lens sheet, and the diffusion sheet are pasted on the surface of the flexible support substrate, whereby total reflection is achieved. To improve the light extraction efficiency.

In order to increase the light extraction efficiency, a method of introducing a diffraction grating or a method of introducing a diffusion structure in an interface or any medium that causes total reflection is known.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

Example << Preparation of organic EL element >>
[Production of Organic EL Element 1]
<Production of gas barrier flexible film>
As a flexible film (flexible support substrate), a polyethylene naphthalate film (a film made by Teijin DuPont Co., Ltd., hereinafter abbreviated as PEN) is formed on the entire surface on the side where the first electrode is formed. Using an atmospheric pressure plasma discharge treatment apparatus having the structure described above, an inorganic gas barrier film made of SiOx is continuously formed on a flexible film so as to have a thickness of 500 nm, and an oxygen permeability of 0.001 ml / ^(m 2 · day) or less, to produce a water vapor permeability of 0.001 g ^/ (m 2 · day) or less of the gas barrier of the flexible film.

<Formation of first electrode layer>
A 120 nm thick ITO (indium tin oxide) film was formed by sputtering on the prepared gas barrier flexible film, and patterned by photolithography to form a first electrode layer. The pattern was such that the light emitting area was 50 mm ² .

<Formation of hole injection transport layer>
The ITO substrate after patterning was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. On this substrate, poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated at 3000 rpm for 30 seconds. After forming into a film by the method, it was dried at 130 ° C. for 1 hour to provide a hole injection transport layer having a thickness of 30 nm.

<Formation of light emitting layer>
A gas barrier flexible film having a hole injecting and transporting layer formed under a nitrogen atmosphere in accordance with JIS B9920, with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or lower, and an oxygen concentration of 0.8 ppm. Moved to the glove box. In the glove box, the following light emitting layer coating solution was formed by spin coating at 2000 rpm for 30 seconds, and then dried at 120 ° C. for 30 minutes to provide a light emitting layer having a thickness of 40 nm.

(Preparation of light emitting layer forming coating solution)
The host compound HA 1.0 g and the dopant compounds DA 100 mg, DB 0.2 mg, and DC 0.2 mg were dissolved in 100 g of toluene to prepare a light emitting layer coating solution.

<Formation of electron transport layer>
Next, on the gas barrier flexible film on which the light emitting layer was formed, the following electron transport layer coating solution was formed by spin coating at 2000 rpm for 30 seconds, and then dried at 120 ° C. for 30 minutes. An electron transport layer having a thickness of 35 nm was provided.

(Preparation of coating solution for electron transport layer)
For the electron transport layer, EA was dissolved in 2,2,3,3-tetrafluoro-1-propanol to obtain a 0.75% by mass solution as a coating solution for the electron transport layer.

<Formation of electron injection layer>
Next, an electron injection layer was formed on the formed electron transport layer. First, the substrate was put into a vacuum chamber and the pressure was reduced to 5 × 10 ⁻⁴ Pa. In advance, potassium fluoride prepared in a tantalum vapor deposition boat was heated in a vacuum chamber and laminated to a thickness of 2 nm. Subsequently, 1 nm of calcium prepared in advance in a tantalum vapor deposition boat was laminated in a vacuum chamber to form an electron injection layer.

<Formation of second electrode>
Subsequently, using the silver as the second electrode forming material under a vacuum of 5 × 10 ⁻⁴ Pa on the formed electron injection layer except for the portion that becomes the extraction electrode on the first electrode, A mask pattern was formed by vapor deposition so that the light emission area was 50 mm square, and a second electrode having a thickness of 100 nm was laminated.

<Formation of heat conduction layer>
Next, aluminum is used as the heat conductive layer material under a vacuum of 5 × 10 ⁻⁴ Pa on the formed second electrode, and the same mask pattern as that of the second electrode is formed. A conductive layer was laminated.

(Cutting)
The gas barrier flexible film formed up to the heat conductive layer was moved again to the nitrogen atmosphere, and the gas barrier flexible film was cut into a prescribed size.

(Sealing)
Then, the flexible sealing member was adhere | attached using the commercially available roll laminating apparatus, and the organic EL element 1 of this invention was manufactured.

As a flexible sealing member, a polyethylene terephthalate (PET) film (12 μm thickness) is bonded to a flexible aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) with a thickness of 30 μm (two-component reactive type). (Urethane type adhesive)) (adhesive layer thickness 1.5 μm) was used.

A thermosetting adhesive as a sealing adhesive was uniformly applied to the aluminum surface with a thickness of 20 μm along the adhesive surface (shiny surface) of the aluminum foil using a dispenser. This was dried under a vacuum of 100 Pa or less for 12 hours. Furthermore, it moved to a nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, dried for 12 hours or longer, and adjusted the water content of the sealing adhesive to 100 ppm or lower.

As the thermosetting adhesive, an epoxy adhesive mixed with the following (A) to (C) was used.

(A) Bisphenol A diglycidyl ether (DGEBA)
(B) Dicyandiamide (DICY)
(C) Epoxy adduct-based curing accelerator After that, a flexible film formed by applying a gas barrier flexible film formed up to the heat conductive layer and a sealing adhesive so as to have a layer structure as shown in FIG. The stop member was closely adhered and arranged, and was closely sealed using a pressure roll at a pressure roll temperature of 120 ° C., a pressure of 0.5 MPa, and an apparatus speed of 0.3 m / min.

<Preparation of organic EL element 2>
In the production of the organic EL element 1, a silver alloy formed by co-evaporating the second electrode so that silver is 97.4 atomic%, palladium is 0.91 atomic%, and copper is 1.69 atomic%; Except that, the organic EL element 2 of the present invention was produced in the same manner.

<Preparation of organic EL element 3>
In the production of the organic EL element 2, the organic EL element 3 of the present invention was produced in the same manner except that the conditions for drying the sealing adhesive applied to the flexible sealing member were changed as follows. The drying was carried out in a nitrogen atmosphere having a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, and dried for about 4 hours, so that the moisture content of the sealing adhesive was adjusted to 200 to 300 ppm.

<Preparation of organic EL element 4>
In the production of the organic EL element 2, the organic EL element 4 of the present invention was produced in the same manner except that the electron injection layer was formed to be 2 nm of potassium fluoride and then formed to be 1 nm of magnesium.

<Preparation of organic EL element 5>
In the production of the organic EL element 1, the organic EL element 5 of the comparative example was produced in the same manner except that the second electrode was aluminum and the heat conductive layer was not provided.

<Preparation of organic EL element 6>
In the production of the organic EL element 1, the organic EL element 6 of the comparative example was produced in the same manner except that the heat conductive layer was not provided.

<Preparation of organic EL element 7>
In the production of the organic EL element 1, the second electrode is a silver alloy formed by co-evaporation so that silver is 97.4 atomic%, palladium is 0.91 atomic%, and copper is 1.69 atomic%. The organic EL element 7 of the comparative example was produced in the same manner except that the heat conductive layer was not provided.

<< Evaluation of organic EL elements >>
The following evaluation was performed about the produced organic EL element.

<External extraction quantum efficiency>
When a constant current of ^2.5 mA / cm ² is applied to the organic EL element in which the light diffusion film (MTN-W1) manufactured by Kimoto Co., Ltd. is pasted on the light extraction surface of the organic EL element via an adhesive layer External extraction quantum efficiency (%) was measured. For the measurement, a spectral radiance meter CS-2000 (manufactured by Konica Minolta Sensing) was used, the luminance in all directions was measured, and the external extraction quantum efficiency was calculated. The external extraction quantum efficiency was expressed as a relative value with the organic EL element 5 as 100.

(Rectification ratio)
The current value when a voltage of +3.5 V was applied to the organic EL element was measured. Subsequently, the current value when a voltage of −3.5 V was applied was measured. The rectification ratio was calculated by dividing the current value at + 3.5V by the current value at -3.5V, and evaluated according to the following criteria.

A: Rectification ratio of 1000 or more (level at which driving is stable)
○: Incidence rate of 500 or more and less than 1000 (slightly inferior but at a level where there is no practical problem)
Δ: Incidence rate of 100 or more and less than 500 (inferior level with practical problems)
×: Incidence rate less than 100 (very inferior, practically problematic level)
Next, as one index of high-temperature storage stability, the organic EL device was stored at 85 ° C. for 300 hours, and the rectification ratio was similarly evaluated.

(Spot)
A voltage of 4 V was applied to the organic EL element to emit light, and the organic EL element was photographed with a microscope (MS-804 manufactured by Moritex Co., Ltd., lens MP-ZE25-200). The photographed image was visually observed to check the situation of black spots. The light emitting surface was divided into 100, and the black spot generation ratio was calculated from the number of black spots generated and evaluated according to the following criteria.

A: Black spot generation rate 0% (no black spots are generated)
○: Black spot generation rate of 1% or more and less than 5% Δ: Black spot generation rate of 5% or more and less than 10% X: Black spot generation rate of 10% or more After storage for hours, the sunspots were evaluated in the same manner.

Table 1 shows the evaluation results.

<Evaluation method for continuous drive stability>
The organic EL element was wound around a cylinder with a radius of 5 cm, and continuously driven for 300 hours in a bent state, and the rectification ratio and black spot were compared with those before continuous driving by the above method. The driving condition was set to a current value of 4000 cd / m ² at the start of continuous driving. The residual luminance was expressed as a relative value with the organic EL element 5 as 100.

Table 2 shows the evaluation results.

From Tables 1 and 2, it can be seen that the organic EL of the present invention has a higher external extraction quantum efficiency than that of the comparative example, a long lifetime, excellent high-temperature storage stability, and excellent driving stability during bending.

DESCRIPTION OF SYMBOLS 1 Flexible support substrate 2 1st electrode 3 Organic compound layer 4 2nd electrode 5 Heat conductive layer 6 Adhesive for sealing 7 Flexible sealing member

Claims

In the organic electroluminescence element having a first electrode, an organic compound layer including at least one light emitting layer made of an organic compound, a second electrode, and a flexible sealing member in this order on a flexible support substrate, An organic electroluminescence element having a heat conductive layer and a sealing adhesive in this order between two electrodes and the flexible sealing member and sealed tightly, wherein the second electrode is made of silver or silver An organic electroluminescence element characterized by being a silver alloy having a main component.
2. The organic electro luminescence device according to claim 1, further comprising a light extraction member between the flexible support substrate and the second electrode or on the opposite side of the flexible support substrate from the first electrode. Luminescence element.
3. The organic electroluminescence device according to claim 1, wherein the sealing adhesive has a water content of 0.01 to 300 ppm.
4. The organic electroluminescence element according to claim 1, wherein the heat conductive layer is made of a metal.
The organic electroluminescence device according to any one of claims 1 to 4, wherein a silver content of the second electrode is 90 atomic percent or more.
In the manufacturing method of the organic electroluminescent element which has a 1st electrode, the organic compound layer which contains at least 1 light emitting layer which consists of an organic compound, a 2nd electrode, and the flexible sealing member in this order on a flexible support substrate. The organic electroluminescence device is disposed between the second electrode and the flexible sealing member in this order, and a heat conductive layer and a sealing adhesive are arranged in this order, and the sealing adhesive is used for tightly sealing. It is a method, Comprising: The said 2nd electrode is silver or the silver alloy which has silver as a main component, The manufacturing method of the organic electroluminescent element characterized by the above-mentioned.
The method for producing an organic electroluminescent element according to claim 6, wherein the moisture content of the sealing adhesive is dried to 300 ppm or less.