CN100531485C - Organic electroluminescent element, method for preparing organic electroluminescent element, and electrode film - Google Patents

Abstract

An organic electroluminescent element comprising a transparent electrode layer, an organic material layer including an organic light-emitting material layer, an opaque electrode layer, an insulating layer, and a metal layer successively formed in the stated order on the surface of a transparent substrate and resin films. Since intrusion of moisture into the light-emitting element is suppressed, the organic electroluminescent element exhibits excellent durability.

Description

Organic electroluminescent element, method for preparing organic electroluminescent element, and electrode film

field of invention

The invention relates to an organic electroluminescent element, a method for preparing the organic electroluminescent element and an electrode film.

Background of the invention

An organic electroluminescent element has a basic structure that sequentially includes a transparent electrode layer, a light-emitting organic material layer, and an opaque electrode layer on the surface of a transparent glass substrate. The transparent electrode layer is an anode (positive electrode) layer. The transparent electrode layer typically comprises a transparent conductive material such as ITO (indium oxide doped with tin). The opaque electrode layer comprising a metallic material such as Mg-Ag alloy is the cathode (negative electrode) layer.

The organic electroluminescent element is a light-emitting element, which injects holes from the anode layer and electrons from the cathode layer into the light-emitting organic material layer, and makes holes and electrons recombine in the light-emitting organic material layer to form electron hole excitation. pairs and deactivates the electron-hole excited pairs, thereby emitting light. Light generated from the light-emitting organic material layer is emitted through the transparent glass substrate.

It has been proposed that a hole transport layer be disposed between the light-emitting organic material layer and the anode layer to improve the injection efficiency of holes into the light-emitting organic material layer. It has also been proposed that an electron transport layer can be arranged between the organic material layer and the cathode layer to improve the injection efficiency of electrons into the light-emitting organic material layer. By increasing the injection efficiency, the hole transport layer and the electron transport layer each have a function of improving the emission efficiency of the organic electroluminescent element. The hole transport layer and the electron transport layer each contain an organic material. As mentioned above, an organic electroluminescence element generally comprises an organic material layer disposed between an anode layer and a cathode layer. The organic material layer includes at least one light-emitting organic material layer.

The cathode layer of the organic electroluminescence element contains an active metal material having a small work function (generally 4 eV or less) that efficiently injects electrons into the organic material layer. Therefore, when the cathode layer comes into contact with moisture or oxygen, degradation of the cathode layer occurs. If moisture or oxygen in the air permeates into the organic electroluminescent element, the degradation of the cathode layer causes problems such as reduction in brightness of the light emitting element, and separation between the cathode layer and the organic layer. Separate regions in the light-emitting element cannot emit light.

Conventional electroluminescent elements are placed in an airtight space that isolates them from the outside air (sealed). The air-tight space is closed with a glass substrate on which a light-emitting element is formed, and the glass plate is fixed around the substrate with a moisture-impermeable glue (hereinafter referred to as a sealing glass plate). It has been proposed to place a layer of hygroscopic material on the inner surface of the sealed glass pane to absorb the moisture remaining in the space after sealing.

Japanese Patent Provisional Publication No. 2000-260562 discloses a hygroscopic film comprising an alkaline earth metal oxide. The publication describes that a moisture-absorbing film provided on the inner surface of the sealing glass plate can prevent moisture from penetrating into the organic electroluminescent element.

Japanese Patent Provisional Publication No. 2003-144830 discloses a desiccant containing an organometallic compound. The publication describes that the moisture-absorbing material provided on the inner surface of the sealing glass plate prevents the penetration of moisture into the organic electroluminescent element. The hygroscopic material layer is formed by dissolving a desiccant in an organic solvent to prepare a solution, applying the solution on the inner side surface of the sealing glass plate and drying it.

Japanese Patent Provisional Publication No. 2002-100469 discloses a method of preventing moisture from penetrating into a light emitting element. The method includes, for example, forming an organic electroluminescence element on a resin substrate, provided that an inorganic barrier film is disposed between the substrate and the element, and the surface is covered with an inorganic passivation film. More specifically, a silicon nitride oxide film is used as an inorganic barrier film, and a silicon nitride film is used as an inorganic passivation film.

invention disclosure

Problems solved by the present invention

The method of attaching each sealing glass plate to the organic electroluminescent element to avoid the penetration of moisture into the light-emitting element (described above) has the disadvantage of low productivity of the light-emitting element. The method of covering the surface of an organic electroluminescence element with an inorganic passivation film also has a disadvantage of low productivity of light emitting elements because a thick inorganic passivation film should be used to obtain low moisture permeability similar to a sealing glass plate.

The object of the present invention is to provide an organic electroluminescent element which prevents moisture from penetrating into a light emitting element, and a high-efficiency method for producing an organic electroluminescent element.

Another object of the present invention is to provide an electrode film that can be used to efficiently manufacture an organic electroluminescence element that prevents moisture from penetrating into a light-emitting element.

The present invention provides an organic electroluminescent element which sequentially comprises a transparent electrode layer, an organic material layer including a light-emitting organic material layer, an opaque electrode layer, an insulating layer, a metal layer and Resin film.

Hereinafter, the organic electroluminescent element having the above structure is referred to as a first organic electroluminescent element. Preferred embodiments of the first electroluminescent element are described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating layer has a thickness of 10-1,000 nm.

(3) Another metal layer is provided on the surface of the resin film.

(4) Another insulating layer and another metal layer are disposed between the opaque electrode and the insulating layer. Other insulating layers and other metal layers are arranged sequentially from the opaque electrode layer.

(5) The insulating layer contains a hygroscopic material.

(6) The hygroscopic material layer is disposed between the insulating layer and the metal layer.

(7) The hygroscopic material contains an alkaline earth metal oxide.

The present invention also provides a method for preparing an organic electroluminescent element, the method comprising the steps of: preparing an electrode substrate and an electrode film, the electrode substrate includes a transparent electrode layer on the surface of a transparent substrate, and the electrode film is formed on a resin film A metal layer, an insulating layer, and an opaque electrode layer are sequentially included on the surface, provided that an organic material layer comprising a light-emitting organic material layer is disposed on the surface of at least one of the transparent electrode layer and the opaque electrode layer; The electrode film is placed on the electrode substrate while being between the transparent electrode layer and the opaque electrode layer; the electrode substrate and the electrode film are pressed while heating the organic material layer to soften it, thereby attaching the electrode film to the electrode substrate .

Hereinafter, the above method of producing an organic electroluminescence element is referred to as a first production method. The first production method of the preferred embodiment is described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating layer has a thickness of 10-1,000 nm.

(3) Another metal layer is provided on the back surface of the resin film.

(4) Another metal layer and another insulating layer are disposed between the insulating layer and the opaque layer. Other metal layers and other insulating layers are arranged sequentially from this insulating layer.

(5) The insulating layer contains a hygroscopic material.

(6) A hygroscopic material layer is disposed between the metal layer and the insulating layer.

(7) The hygroscopic material layer contains an alkaline earth metal oxide.

The present invention further provides an electrode film comprising a metal layer, an insulating layer and an opaque electrode layer in this order on the surface of the resin film.

The electrode film having the above structure is hereinafter referred to as a first electrode film. Preferred embodiments of the first electrode film are described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating layer has a thickness of 10-1,000 nm.

(3) Another metal layer is provided on the back surface of the resin film.

(4) Another metal layer and another insulating layer are disposed between the insulating layer and the opaque layer. Other metal layers and other insulating layers are arranged sequentially from this insulating layer.

(5) The insulating layer contains a hygroscopic material.

(6) A hygroscopic material layer is disposed between the metal layer and the insulating layer.

(7) The hygroscopic material layer contains an alkaline earth metal oxide.

The present invention further provides a rolled electrode film obtained by rolling the first electrode film into a roll.

Hereinafter, the rolled electrode film having the above structure will be referred to as a first rolled electrode film.

Furthermore, the present invention provides an organic electroluminescent element comprising, on the surface of a transparent substrate, a transparent electrode layer, an organic material layer including a light-emitting organic material layer, an opaque electrode layer, a resin film, and a metal layer.

The organic electroluminescent element having the above structure is referred to herein as a second organic electroluminescent element. Preferred embodiments of the second organic electroluminescence element are described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating moisture-absorbing material layer is disposed between the opaque electrode layer and the resin film.

(3) An insulating layer and a hygroscopic material layer are disposed between the opaque electrode layer and the resin film. The insulating layer and the hygroscopic material layer are sequentially arranged from the opaque electrode layer.

(4) The insulating material contains an alkaline earth metal oxide.

The present invention also provides a method for preparing an organic electroluminescent element, the method comprising the following steps: preparing an electrode substrate and an electrode film, the electrode substrate comprising a transparent electrode layer on the surface of the transparent substrate, and the electrode film comprising a resin film on the surface The opaque electrode layer and the metal layer on the back of the resin film, provided that an organic material layer including a light-emitting organic material layer is disposed on the surface of at least one of the transparent electrode layer and the opaque electrode layer; after the organic material layer is disposed on The electrode film is placed on the electrode substrate while being between the transparent electrode layer and the opaque electrode layer; the electrode substrate and the electrode film are pressed while the organic material layer is heated to soften it, thereby attaching the electrode film to the electrode substrate .

Hereinafter, the above method of producing an organic electroluminescence element is referred to as a second production method. Preferred embodiments of the second production method are described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating hygroscopic material layer is disposed between the resin film and the opaque electrode layer.

(3) A hygroscopic material layer and an insulating layer are disposed between the resin film and the opaque electrode layer. The hygroscopic material layer and the insulating material layer are sequentially provided from the resin film.

(4) The hygroscopic material includes alkaline earth metal oxides.

The present invention further provides an electrode film comprising an opaque electrode layer on the surface of the resin film and a metal layer on the back of the resin film.

The electrode film having the above structure is hereinafter referred to as a second electrode film. Preferred embodiments of the second electrode film are described below.

(1) The metal layer has a thickness of 10-500 nm.

(2) The insulating hygroscopic material layer is disposed between the resin film and the opaque electrode layer.

(3) A hygroscopic material layer and an insulating layer are disposed between the resin film and the opaque electrode layer. The hygroscopic material layer and the insulating material layer are sequentially provided from the resin film.

(4) The hygroscopic material includes alkaline earth metal oxides.

The present invention further provides a rolled electrode film obtained by rolling the second electrode film into a roll.

Hereinafter, the rolled electrode film having the above structure is referred to as a second rolled electrode film.

In this specification, the term "transparent" means that the transmittance of visible light is 60% or higher, preferably 70% or higher. The term "opaque" means that the transmittance of visible light is 30% or less, preferably 20% or less.

Effect of the present invention

The electrode film of the present invention has a basic structure that sequentially includes a metal layer, an insulating layer and an opaque electrode layer on the surface of the resin film. In the electrode film of the present invention, the metal layer prevents moisture from penetrating into the resin film. Moreover, since the metal layer has excellent flexibility, the electrode film can be rolled into a roll. Since the durability of the organic electroluminescent element is improved by preventing moisture from penetrating into the light emitting element, the organic electroluminescent element can be produced with high efficiency using an electrode film or a rolled electrode film. The durability of the organic electroluminescent element can be further improved by preparing an insulating material from a hygroscopic material, or disposing a layer of a hygroscopic material between a metal layer and an insulating layer, so that the moisture remaining in the light-emitting element is absorbed and removed by the hygroscopic material. .

Best Mode for Carrying Out the Invention

The first organic electroluminescence (hereinafter referred to as EL) of the present invention sequentially comprises an organic material layer including a light-emitting organic material layer, an opaque electrode layer, an insulating layer, a metal layer and a resin film on the surface of a transparent substrate. The transparent electrode layer of the organic EL element is usually an anode (positive electrode) layer, and the opaque electrode layer is usually a cathode (negative electrode) layer. The invention is described below by reference to an embodiment having a transparent anode layer and an opaque cathode layer.

FIG. 1 is a cross-sectional view showing a structural example of a first organic EL element. The first organic EL element 11 sequentially includes an anode (transparent electrode) layer 15, an organic material layer including a light-emitting organic material layer, a cathode (opaque electrode) layer 25, an insulating layer 24, a metal layer 23, and a resin on the surface of a transparent substrate 12. film22. The organic material layer of the organic EL element includes a hole transport layer 16 and a light-emitting organic material layer 17 . The light generated in the light-emitting organic material layer 17 is emitted from the light-emitting element through the transparent substrate 12 . Arrow 10 shown in FIG. 1 indicates the direction in which light is emitted.

A substrate with low moisture permeability was used as the transparent substrate 12 . Examples of the transparent substrate 12 include ceramic substrates such as glass substrates and resin substrates (or resin films) subjected to moisture-repellent treatment. Examples of moisture-repellent treatment for resin substrates include forming a low-moisture-permeable film on the surface of a resin film. Examples of the low moisture permeability film include a silicon oxide film, a silicon nitride film, a silicon nitride oxide film, and a metal film. In the case of using a metal film, the thickness of the film should be controlled so that the film transmits visible light so that light generated in the light-emitting organic material layer is emitted from the light-emitting element. Therefore, a metal film used as a low water permeability film preferably has a thickness not greater than several nanometers.

The periphery of the organic EL element is subjected to a moisture-repellent treatment to prevent moisture from penetrating into the light-emitting element from the periphery. Examples of the moisture-repelling treatment include a method of forming a low moisture-permeable resin layer on the periphery of the organic EL element. The resin layer with low moisture permeability can be formed by coating a resin and drying the coated resin at room temperature, or drying the resin by irradiating the periphery of the light emitting element with ultraviolet rays. Examples of resins include epoxy resins and acrylic resins. The resin used for the moisture-repelling treatment may be the same resin contained in the adhesive used to attach the sealing glass plate to the conventional organic EL element (described above).

The organic EL element 11 is characterized in that the insulating layer 24 , the metal layer 23 and the resin film 22 are provided on the surface of the cathode layer 25 . The insulating layer 24 is located between the surface of the cathode layer 25 and the metal layer. The metal layer contains a metal material and has low moisture permeability. The metal layer 23 is provided on a surface through which light generated in the light-emitting organic material layer of the organic EL element 11 is not emitted. In other words, the metal layer is disposed outside the light-tight cathode layer 25 . The metal layer 23 can prevent moisture from penetrating into the light emitting element from the cathode layer 25 . Another metal layer other than the above-mentioned metal layer 23 may be formed on the surface of the resin film 22 (a surface different from the surface on which the metal layer 23 is provided) to prevent moisture from permeating from the cathode layer 25 into the light-emitting element.

The electrode film used to prepare the organic EL element shown in Fig. 1 will be described below.

FIG. 2 is a cross-sectional view showing an example of the structure of a first electrode film used to manufacture the organic EL element shown in FIG. 1 . The first electrode film 21 sequentially includes a metal layer 23 , an insulating layer 24 and a cathode (opaque electrode) layer 25 on the surface of the resin film 22 .

Examples of the resin film 22 include polyester films (such as polyethylene terephthalate films), polycarbonate films, polyimide films, polyethersulfone films, polyetherimide films, polyethylene sulfide films, Polysulfone film, polyether ether ketone film, polyamide film, polymethyl methacrylate film, polyethylene naphthalate film, polyarylate film and cycloolefin polymer film.

The resin film 22 preferably has a thickness of 3-1,000 μm, more preferably 10-500 μm, most preferably 10-300 μm.

The metal layer 23 contains a metal material. This metallic material has low moisture permeability and excellent flexibility. In the first electrode film 22, the metal layer 23 prevents moisture from permeating through the resin layer. Since the metal layer 23 is bendable, the electrode film 21 can be wound into a roll. Another metal layer other than the metal layer 23 may be provided on the back of the resin film 22 (a surface different from the surface on which the metal layer 23 is provided) in order to prevent moisture from permeating through the resin film 22 .

Examples of metal materials for the metal layer 23 include gold, silver, copper, aluminum, titanium, palladium, platinum, and alloys containing at least one of the above metal materials.

Examples of a method of forming the metal layer 23 include a dry forming method such as a vacuum deposition method or a spray coating method, and a wet forming method such as a gravure printing method or a doctor blade coating method.

The metal layer 23 has a thickness of preferably 5-500 nm, more preferably 10-500 nm. The thickness is adjusted so that no cracks are formed when the electrode film 21 is wound into a roll.

The insulating layer disposed between the metal layer 23 and the cathode layer 25 prevents electrical communication between the metal layer and the cathode. In the case where two or more cathode layers (eg cathode layer strips) are formed on the surface of the insulating layer, the insulating layer prevents an open circuit caused by electrical communication between the cathode layer and the metal layer 23 .

The material used for the insulating layer may be a known insulating material. Examples of insulating materials include metal oxide materials such as TiO ₂ , Al ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , SiO ₂ or Si ₃ N ₄ , and irradiated by heat radiation or by light (preferably ultraviolet rays) at room temperature Hardened resin material. Examples of resin materials include epoxy resins and acrylic resins.

Examples of methods of forming insulating layer 24 include dry forming methods such as vacuum deposition or spray coating, and wet forming methods such as screen printing, gravure printing, or inkjet printing.

The insulating layer 24 has a thickness preferably in the range of 10-1,000 nm. The thickness of the insulating layer is adjusted in accordance with the hardness of the material of the insulating layer so that no cracks are formed when the electrode film 21 is wound into a roll. The thickness of the insulating layer is more preferably in the range of 10-500 nm, further preferably in the range of 10-180 nm, and most preferably in the range of 10-150 nm.

The material and thickness of the cathode layer are the same as those of conventional organic EL elements. The material and thickness are described below.

An adhesive layer is provided between the resin film 22 and the metal layer 23 to improve the adhesive force therebetween. An insulating material forming the insulating layer 24 may be used as a material forming the adhesive layer. The preferred range of thickness of the adhesive layer is the same as that of the insulating layer 24 .

Fig. 3 is a sectional view showing another example of the thin film structure of the first electrode of the present invention. Except that another metal layer 33 and another insulating layer 34 are arranged between the insulating layer 24 and the cathode (opaque electrode) layer 25, the structure of the electrode film 31 shown in FIG. 3 is the same as that of the electrode film shown in FIG. 2 . The other metal layer 33 and the other metal layer 34 are sequentially arranged by the insulating layer 24 . As shown in FIG. 3, the two metal layers 23, 24 provided in the electrode film 31 prevent moisture or oxygen from penetrating into the organic EL element.

Fig. 9 is a sectional view showing another example of the thin film structure of the first electrode of the present invention. The electrode film 91 shown in FIG. 9 includes a metal layer 23 , a hygroscopic material layer 29 , an insulating layer 24 and a cathode layer 25 on the surface of the resin film 22 in sequence. Except that the hygroscopic material layer 29 is disposed between the metal layer 23 and the insulating layer 24 , the structure of the electrode film 91 is the same as that of the electrode 21 shown in FIG. 2 .

As the material of the hygroscopic material layer 29, known hygroscopic materials capable of being molded into layers can be used. Representative examples of hygroscopic materials include oxides of alkaline earth metals (Ca, Sr, Ba, Ra, Be, Mg) disclosed in Japanese Patent Provisional Publication No. 2000-260562, and organometallic compounds such as octanoic acid disclosed in Japanese Patent Provisional Publication No. 2003-144830. Alumina (aluminum oxide octylate).

Examples of methods of forming the hygroscopic material layer 29 from alkaline earth metal oxides include an electron beam deposition method and a spraying method. The spraying method preferably uses targets made of alkaline earth metal peroxides. The hygroscopic material layer is preferably a strontium oxide (SrO) layer formed by a spray coating method using strontium peroxide (SrO ₂ ) as a target.

Examples of methods of forming the hygroscopic material layer 29 from an organometallic compound include methods of coating or printing with a solution in which an organometallic compound such as aluminum oxide caprylate is dissolved in an organic solvent such as toluene or xylene.

Another hygroscopic material is a mixture of desiccant and resinous material.

For example, Japanese Patent Provisional Publication No. 2001-345175 discloses a method for producing an organic EL element, the method comprising coating the surface of a sealed glass plate with a mixture of a solid powder desiccant and a resin material to form a layer, and using a sealant having a layer of the mixture glass plate. The publication further describes mixing and dispersing BaO (desiccant) powder in a liquid silicone rubber capable of being hardened, and coating a sealing glass plate with the suspension according to the doctor blade method.

Japanese Patent Provisional Publication No. 2001-57287 discloses an organic EL element in which a sealing plate has a layer of a mixture of a desiccant and a resin material. The publication further describes a method of coating sealed glass panels with a mixture of _CaH2 (drying agent) and liquid silicone rubber capable of hardening to form a layer of the mixture.

The electrode film of the present invention can be prepared by the following method: In the same method as in the above disclosure, on the surface of the metal layer formed on the resin film, for example, a hygroscopic material layer is formed, and the hygroscopic material layer contains a mixture of a desiccant and a resin material, Then an insulating layer and a cathode layer are formed.

The hygroscopic material layer 29 has a thickness of preferably 100 μm or less, more preferably in the range of 0.1-30 μm.

The organic EL element prepared with the electrode film 91 having the hygroscopic material layer 29 has excellent durability because the metal layer 23 prevents moisture from penetrating into the light-emitting element through the resin layer 22, and the hygroscopic material layer 29 bonds the electrode film to the electrode Moisture remaining in the light-emitting element behind the substrate is absorbed. A light-emitting element can be efficiently produced using an electrode film having a hygroscopic material layer, whereas a conventional organic EL element is prepared by forming a hygroscopic material layer on a sealed glass plate and sealing each element with a glass plate.

In the case where the hygroscopic material is an insulating material, the insulating layer may be made of an insulating hygroscopic material without providing the hygroscopic material layer 29 in the electrode film 91 . Examples of insulating hygroscopic materials include alkaline earth metal oxides disclosed in Japanese Patent Provisional Publication No. 2000-260562, and organometallic compounds disclosed in Japanese Patent Provisional Publication No. 2003-144830.

In the case where the insulating layer 24 is made of an insulating hygroscopic material, the insulating layer 24 has a thickness of preferably 100 μm or less, and more preferably in the range of 0.1-30 μm.

Fig. 4 shows an example of the structure of the first rolled electrode film of the present invention. The rolled electrode film 20 shown in FIG. 4 is obtained by rolling the electrode film 21 into a roll. The electrode film 21 sequentially includes a metal layer 23 , an insulating layer 24 and a cathode layer 25 on the surface of the resin film 22 . By rolling the electrode film 21 into a roll, the cathode layer 25 is kept out of contact with the air, thereby preventing degradation of the cathode layer 25 .

The rolled electrode film 20 is prepared by rolling the electrode film 21 into a roll, preferably under reduced pressure or in an atmosphere of inert gas (such as nitrogen) to prevent degradation of the cathode layer 25 . The rolled electrode film 20 as a whole is packaged under reduced pressure or filled with an inert gas while being packaged.

As shown in FIG. 4 , the metal layer 23 is preferably provided on the surface of the outermost resin film 20 of the rolled electrode film 20 . In the rolled electrode film 20 shown in FIG. 4 , the film as a whole is rolled up, and the outermost roll is wrapped with a metal layer 23 . Therefore, by wrapping the outermost roll (for example, the last roll) of the rolled film with the metal layer 23, moisture can be prevented from penetrating into the rolled electrode film 20 from the outermost roll, thereby more effectively preventing the degradation of the cathode layer. On two or more outer rolls of the rolled electrode film 20, a metal layer may be provided on the surface of the resin film.

The electrode film is preferably rolled up with a tension of 2.5×10 ⁵ -4.0×10 ⁷ N/m ² to prevent moisture from penetrating into the rolled electrode film 20 from the side of the roll. After rolling the film while applying tension to the surface of the resin film, adjacent electrode films are attached to each other, thereby more effectively preventing moisture from penetrating into the roll electrode film from the side of the roll.

The electrode film 21 is preferably rolled around a core tube (made of paper, resin or metal) to form a roll. The core tube is preferably made of metal, or the surface of the core tube is preferably wrapped with a metal film to prevent moisture from penetrating into the rolled electrode film through the core tube. The core tube has a diameter preferably in the range 30-300 mm, more preferably in the range 50-200 mm, and most preferably in the range 70-175 mm.

A method of producing an organic EL element using the first electrode film will be described below. The organic EL element is prepared by disposing a first electrode thin film on an electrode substrate which sequentially includes a transparent anode layer and an organic material layer including a light-emitting organic material layer on the surface of a transparent substrate, while placing The organic material layer is arranged between the cathode layer and the anode layer and made to adhere to each other.

Fig. 5 shows an example of a method of producing the organic EL element of the present invention (first production method). In the first preparation method shown in FIG. 5 , an electrode substrate 51 comprising an anode (transparent electrode) layer 55 and an organic material layer 56 sequentially on the surface of a glass substrate (transparent substrate) 52 is prepared first. And prepare the rolled electrode film 20 shown in FIG. 4 . In FIG. 5 , the metal layer and the insulating layer are omitted from the roll electrode film 20 .

The electrode substrate 51 is provided on the substrate transfer film 50 . The electrode substrate 51 stack and the electrode film 21 pass between a pair of heated rolls 57 a , 57 b while disposing the organic material layer 56 between the anode layer 55 and the cathode layer 25 . The electrode substrate 51 laminate and the electrode thin film are pressed and heated on heated rolls 57a, 57b. The organic material layer 56 is heated and softened so that the electrode thin film 21 is attached to the electrode substrate 51 . As a result, an organic EL element 58 was produced. An organic EL element that prevents moisture from penetrating into the light-emitting element can be continuously and efficiently produced using the roll electrode film 20 without using a conventional sealing glass plate. For one light-emitting element, two or more organic EL elements produced continuously can be cut into one. As above, the periphery of the element is subjected to a moisture-repellent treatment.

Fig. 6 shows another example of the production method of the organic EL element of the present invention (first production method). In the preparation method shown in FIG. 6 , the rolled electrode substrate 60 and the rolled electrode film 20 shown in FIG. 4 are first prepared. The rolled electrode substrate 60 is obtained by rolling up an electrode substrate including a transparent electrode layer 65 and an organic material layer 66 in this order on the surface of a transparent film (transparent substrate) 62 . In FIG. 6 , the metal layer and the insulating layer are omitted from the roll electrode film 20 .

A resin film (described above) having a low moisture permeability film can be used as the transparent film 62 of the electrode substrate 61 .

The stack of electrode substrates 61 and the electrode film 21 are passed between a pair of heated rolls 57 a , 57 b while disposing an organic material layer 66 between the anode layer 56 and the cathode layer 25 . The electrode substrate 61 laminate and the electrode thin film are pressed and heated on the heating rolls 57a, 57b. The organic material layer 66 is heated and softened so that the electrode thin film 21 is attached to the electrode substrate 61 . As a result, an organic EL element 58 was produced. An organic EL element that prevents moisture from penetrating into the light-emitting element can be manufactured continuously and efficiently by using the roll electrode film 20 without using a conventional sealing glass plate. For one light-emitting element, two or more organic EL elements produced continuously can be cut into one. The periphery of the element is subjected to a moisture-repellent treatment.

The second organic EL element of the present invention will be described below. The second organic EL element sequentially includes a transparent electrode layer, an organic material layer including a light-emitting organic material layer, an opaque electrode layer, a resin film, and a metal layer on a transparent substrate surface. The second organic EL element is described below by referring to an embodiment having a transparent anode layer and an opaque cathode layer.

Fig. 7 is a cross-sectional view showing an example of the structure of a second organic EL element. The second organic EL element 71 sequentially includes an anode (transparent electrode) layer 15, an organic material layer including a light-emitting organic material layer, a cathode (opaque electrode) layer 25, a resin film 22, and a metal layer 23 on a transparent substrate surface. The organic material layers of the organic EL element 71 include a hole transport layer 16 and a light-emitting organic material layer 17 .

The structure of the organic EL element shown in FIG. 7 is the same as that of the organic EL element shown in FIG. The structure of the organic EL element shown in Fig. 1 is the same. In the structure of the organic EL element shown in FIG. 7 , the resin 22 electrically insulates the metal layer 23 from the cathode layer 25 . Therefore, an insulating layer is unnecessary.

In the organic EL element 71, a metal layer is provided on the resin film in order to prevent moisture from permeating through the cathode 25 into the light emitting element. The metal layer is provided on a surface from which light generated in the light-emitting organic material layer of the light-emitting element is not emitted, in other words, on a surface that does not require light transmission.

FIG. 8 is a sectional view showing an example of the structure of a second electrode film used to manufacture the organic EL element shown in FIG. 7 . The electrode film 81 includes a cathode (opaque electrode) on the surface of the resin film 22 and a metal layer 23 on the back of the resin film. By rolling up the second electrode film 81, a second rolled electrode film can be obtained.

A method of manufacturing an organic EL element using a second electrode film (second manufacturing method) will be described below. An organic EL element can be produced by, for example, disposing a second electrode thin film on an electrode substrate that sequentially includes an anode (transparent electrode) layer, and an organic layer including a light-emitting organic material layer on a transparent substrate surface. The material layer, and the organic material layer is arranged between the anode layer and the cathode layer, and the electrode film is attached to the electrode substrate. The second manufacturing method can be performed in the same manner as the first manufacturing method except that the second electrode film is used. According to the second method, in the same manner as the first method, an organic EL element that prevents moisture from penetrating into the light-emitting element can be continuously and efficiently produced.

Fig. 10 is a sectional view showing another example of the film structure of the second electrode of the present invention. The electrode film 101 shown in FIG. 10 includes a hygroscopic material layer 29, an insulating layer 24, a cathode layer 25 on the surface of the resin film 22, and a metal layer on the back of the resin film. The structure of the resin film 101 is the same as that of the electrode film 81 shown in FIG. The hygroscopic material layer 29 and the insulating layer 24 are provided in order from the resin film. The material and method for preparing the hygroscopic material layer 29 of the electrode film shown in FIG. 10 are the same as those of the electrode film 81 shown in FIG. 8 .

The organic EL element prepared using the electrode film 101 having the hygroscopic material layer 29 shown in FIG. 10 had the same improved durability as the element prepared using the electrode film 91 shown in FIG. In the organic EL element, the metal layer 23 prevents moisture from permeating through the resin film 22 into the light-emitting element. Moreover, the hygroscopic material layer 29 can absorb moisture remaining in the light-emitting element after the electrode film is attached to the electrode substrate. Therefore, degradation of the electrode layer 25 is effectively suppressed, so that durability can be improved. Using an electrode film having a layer of a hygroscopic material, an organic EL element can be produced efficiently.

As described in relation to the electrode film 91 shown in FIG. 9, the insulating layer 24 may be formed with a hygroscopic material layer instead of the hygroscopic material layer 29 forming the electrode film 101 shown in FIG.

The layered structure and materials of the anode layer, organic material layer and cathode layer in the organic EL element of the present invention are described below. The anode layer, the organic material layer and the anode layer can be prepared in the same manner as in known organic EL elements.

The organic material layer of the organic EL element includes one layer or two or more layers including at least one light-emitting organic material layer. As described above, a hole transport layer may be disposed between the light-emitting organic material layer and the anode layer to improve the light-emitting performance of the organic EL element. An electron transport layer can also be disposed between the organic material layer and the cathode layer to improve light emission performance. Examples of the layered structure of the organic EL element of the present invention are described below.

An example of the layered structure of the first organic EL element is explained below.

(a) Transparent substrate/anode layer/light emitting organic material layer/cathode layer/insulating material layer/metal layer/resin film

(b) Transparent substrate/anode layer/hole transport layer/light-emitting organic material layer/cathode layer/insulating layer/metal layer/resin film

(c) Transparent substrate/anode layer/light emitting organic material layer/electron transport layer/cathode layer/insulating layer/metal layer/resin film

(d) Transparent substrate/anode layer/hole transport layer/light emitting organic material layer/electron transport layer/cathode layer/insulating layer/metal layer/resin film.

An example of the layered structure of the second organic EL element is explained below.

(a) Transparent substrate/anode layer/light emitting organic material layer/cathode layer/resin film/metal layer

(b) Transparent substrate/anode layer/hole transport layer/light-emitting organic material layer/cathode layer/resin film/metal layer

(c) Transparent substrate/anode layer/light emitting organic material layer/electron transport layer/cathode layer/resin film/metal layer

(d) Transparent substrate/anode layer/hole transport layer/light emitting organic material layer/electron transport layer/cathode layer/resin film/metal layer.

In addition to the hole transport layer and the electron transport layer, various layers (such as a hole transport layer that can be provided between the anode layer and the organic material layer, or an electron transport layer that can be provided between the cathode layer and the organic material layer) can also be used. transport layer) is provided between the anode layer and the cathode layer in the organic EL element to improve the light emission characteristics of the light emission element or the like. The materials forming the layers will be described in more detail later.

In the preparation of the organic EL element of the present invention by attaching an electrode film having a cathode electrode layer to an electrode substrate having an anode electrode layer, an organic material layer including a light-emitting organic material layer may be provided on the surface of the anode layer or the cathode layer s surface. Also, the organic material layer may be divided into two layers along an interface parallel to the surface plane of the layer. One of the two divided layers may be provided on the surface of the anode layer while the surface resulting from the separation is provided as the uppermost surface, and the other layer may be provided on the surface of the cathode layer while the surface resulting from the separation is provided as top surface. The organic material layer having a certain space in the thickness direction may be divided along the interface between the layers. It is also possible to divide the organic material layer along a plane parallel to the surface plane of the layer (for example in the case of layered structure (a) described above the light-sensitive organic material layer can be divided along a plane parallel to the surface plane).

Simultaneously with bonding the electrode film to the electrode plate, the organic material layer provided on the surface of at least one of the anode layer and the cathode layer is heated to soften. If the heating temperature is very high, the thickness of the softened layer varies greatly while the electrode film is attached to the electrode plate. If the heating temperature is very low, it is difficult to make the electrode plate and the electrode film firmly adhere to each other. The temperature at which the layer of organic material is heated is preferably within the range of ±25°C of the glass transition temperature (Tg) at which the layer is softened (Tg±25°C), and more preferably within the range of ±20°C of the glass transition temperature (Tg±20°C). ℃).

The anode layer contains a metal with a large work function (4eV or greater), a conductive compound, or a mixture thereof. Examples of metals used for the anode layer include ITO (indium oxide doped with tin) and IZO (indium tin oxide).

The anode layer has a thickness of usually 1 μm or less, preferably 200 nm or less. The anode layer has an electrical resistance preferably less than several hundred Ω/square. Examples of methods of forming the anode layer include a vacuum deposition method, a direct current (DC) spray method, a radio frequency (RF), a spin coating method, a casting method, an LB method, a melt-sol method, and a spray method.

Examples of materials for the hole transport layer include tetraarylbenzidine compounds, aromatic amines, pyrazolone derivatives, and benzo[9,10]phenanthrene derivatives.

The hole transport layer has a thickness preferably in the range of 2-200 nm. Examples of methods of forming the hole transport layer include a vacuum deposition method, a spin coating method, a casting method, an LB method, and a printing method.

An electron acceptor may be added to the hole transport layer to increase the mobility of holes. Examples of electron acceptors include metal halides, Lewis acids, and organic acids. It is known to add electron acceptors to hole transport layers.

The light-emitting organic material layer may be made of a light-emitting organic material and a carrier-transporting (hole-transporting, electron-transporting, or amphoteric-transporting) organic material (hereinafter referred to as a host material) added with a small amount of the light-emitting organic material. The emission color of the organic EL element can be easily determined by selecting a light-emitting organic material for the light-emitting organic material layer.

In the case where the light-emitting organic material layer is made of a light-emitting organic material, the light-emitting organic material preferably exhibits excellent film-forming properties, and the formed layer is preferably stable. Examples of the light-emitting organic material layer include metal complexes such as Alq ₃ (tris-(8-hydroxyquinolinato)aluminum, polyphenylenevinylene (PVV) derivatives, and polyfluorene-derived A small amount of light-emitting organic material is used with the host material. Therefore, another light-emitting organic material such as a fluorescent dye, which can hardly form a stable thin layer by itself, can be used with the host material. Examples of fluorescent materials include Coumarin, DCM derivatives, quinacridone, perylene, and rubrene. Examples of matrix materials include the aforementioned Alq ₃ , TPD (triphenylhydrazine), electron-transporting oxadiazole derivatives (PBD), and polycarbonate Ester copolymer and polyvinyl carbazole. In the case where the light-emitting organic material layer is made of a light-emitting organic material, a small amount of another light-emitting organic material such as a fluorescent dye can be added to the layer to adjust the intensity of the emitted light color.

The light-emitting organic material layer has a thickness of 200 nm or less to emit light of practical brightness. The light-emitting organic material layer can be formed in the same manner as the hole transport layer.

Examples of materials for the electron transport layer are electron transport materials including heterocyclic tetracarboxylic anhydrides such as nitrofluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene 3-pentene-1- Alkyne derivatives, carbodiimides, fluorenylidene methane derivatives, anthraquinone dimethanes (dimethanes), anthrone derivatives, oxadiazole derivatives, quinoline derivatives, quinoxaline derivatives, perylene derivatives , pyridine derivatives, pyrimidine derivatives and stilbene derivatives. Aluminum quinolate complexes such as tris-(8-quinolinolato)aluminum (Alq) can also be used as electron transport materials.

The electron transport material layer has a thickness preferably in the range of 5-300 nm. The electron transport layer can be formed in the same manner as the hole transport layer.

The cathode layer may be formed of a metal having a small work function (4 eV or less), an alloy composition, a conductive compound, or a mixture thereof. Examples of materials for the cathode layer include metals such as Al, Ti, In, Na, K, Mg, Li, Cs, Rb, rare earth metals, and alloy compositions such as Na-K alloys, Mg-Ag alloys, Mg-Cu alloys , Al-Li alloy.

The cathode layer has a thickness of usually 1 μm or less, and preferably 200 nm or less. The cathode layer has an electrical resistance preferably less than several hundred Ω/square. The cathode layer can be formed in the same manner as the anode layer.

A hole injection layer may be disposed between the anode layer and the organic material layer. An electron injection layer may also be provided between the cathode layer and the organic material layer. The injection layer has a function of injecting many charges (holes or electrons) from the electrode layer to the organic material layer. The injection layer has a function of smoothing the rough surface of the electrode layer or lowering the driving voltage of the organic EL element.

A representative example of the material for the hole injection layer is copper phthalocyanine (CuPc), and a representative example of the material for the electron injection layer is an alkali metal compound such as LiF (lithium fluoride). The hole injection layer is also called an anode buffer layer, and the electron injection layer is also called a cathode buffer layer.

Example 1

Run the reel PET film (film width: 25cm, thickness: 0.1mm) on the rotating reel drive wheel, and then use a magnetron spraying device to form a thin titanium dioxide film (insulation layer, thickness 20nm) on the running PET film .

Silver is used as a spraying target and argon is used as a spraying gas to form a thin silver film. Titanium is used as a spraying target, and a mixed gas of argon and oxygen is used as a spraying gas to form a thin titanium dioxide film.

The film run was stopped and a metal mask was placed on the surface of the thin titania film. A magnetron spraying device was used to form a thin (thickness: 200nm) Mg-Ag alloy film. A thin Mg-Ag alloy film is formed using the Mg-Ag alloy as a target and argon as a spray gas. The metal mask was removed from the formed strip of thin Mg-Ag alloy thin film (cathode layer), which was stretchable in the longitudinal direction of the film. Electrode thin films were thus prepared.

The prepared electrode film was rolled up on a rotating wheel while a tension of 1.37×10 ⁶ N/m ² was applied thereto under reduced pressure to prepare a rolled electrode film. The prepared film had such a structure that the metal layer was provided on the surface of the PET film which was the outermost roll of the roll electrode film. This structure can prevent the penetration of moisture through the outermost rolled surface of the rolled electrode film.

Example 2

The glass plate on which the strips of ITO thin film (transparent anode layer) were formed was washed. Using a rotary sprayer, spraying at 3,500 rpm for 30 seconds, the surface of the ITO film was coated with a coating solution for forming a hole transport layer (PEDOT/PSS solution, available from Bayer AG Leverlusen). The coated film was dried in an oven at 130° C. under reduced pressure for 1 hour to form a hole transport layer having a thickness of 50 nm.

A light-emitting organic material layer (Green K, available from American Dye Source) was dissolved in xylene to prepare a 1.5 wt% solution as a coating solution for forming the light-emitting organic material layer. Using a rotary sprayer, in the same manner as forming the hole transport layer, the surface of the hole transport layer was coated with the prepared coating solution for forming a light-emitting organic material layer to form a light-emitting organic material having a thickness of 50 nm. layer.

While disposing the organic material layer (hole transport layer and light-emitting organic material layer) between the anode layer and the cathode layer, the electrode film prepared in Example 1 was placed on the surface on which the light-emitting organic material layer was formed . The electrode layers are arranged such that the electrode layer strips cross each other. The laminated glass plate and electrode film were passed through two heated rollers at a predetermined temperature of 140°C to soften the light-emitting organic material layer. The plate and the film are combined to prepare an organic electroluminescence element.

Example 3

Run the reel of PET film on the rotating reel drive wheel. With magnetron spraying device, with the same method as in embodiment 1, form thin titanium dioxide film (thickness: 30nm), thin silver film (metal layer, thickness: 20nm) on the PET film of operation, then thin titanium dioxide film ( insulating layer, thickness: 30 nm).

The film run was stopped and a metal mask was placed on the surface of the thin titania film. A magnetron spraying device was used to form a thin (thickness: 160 nm) ITO film. The thin ITO film is formed by using ITO as the spraying target and the mixed gas of argon and oxygen as the spraying gas. The metal mask was removed from the formed strip of thin ITO film (transparent anode layer), which was stretchable in the longitudinal direction of the film.

A thin ITO film was coated with the coating solution used to form the hole transport layer used in Example 2 according to the gravure method. The coated film was dried to form a hole transport layer having a thickness of 50 nm. According to the gravure coating method described above, the surface of the hole transport layer was coated with the coating solution for forming the light-emitting organic material layer used in Example 2. The coated film was dried to form a light-emitting organic material layer having a thickness of 50 nm. Thus, an electrode substrate was prepared.

In the same manner as in the preparation of the electrode film in Example 1, the prepared electrode substrate was rolled up to prepare a rolled electrode substrate. The rolled electrode has a structure in which a metal layer is provided on the surface of the outermost rolled metal thin film. This structure can prevent the penetration of moisture through the outer surface of the rolled electrode substrate.

While disposing the organic material layer (hole transport layer and light-emitting organic material layer) between the anode layer and the cathode layer, the electrode thin film prepared in Example 1 was placed on the prepared electrode substrate. The electrode layers are arranged such that the electrode layer strips cross each other. The layered glass electrode plate and electrode film were passed through two heated rollers at a predetermined temperature of 140°C to soften the light-emitting organic material layer. The plate and the film are combined to prepare an organic electroluminescence element.

Example 4

Run the reel of PET film on the reel rotating drive wheel. With a magnetron spraying device, with the same method as in Example 1, a thin silver film (metal layer, thickness: 100nm), a thin strontium oxide (SrO) layer (hygroscopic material layer, Thickness: 1 μm), then a thin titanium dioxide film (insulating layer, thickness: 20 nm).

Sintered strontium peroxide (SrO ₂ ) powder is used as a spraying target and oxygen as a spraying gas to form a thin strontium oxide film.

A thin Mg-Ag film strip (anode layer, thickness: 200 nm) was formed on the thin titanium oxide layer in the same manner as in Example 1 for forming the electrode film. The formed electrode film was rolled up in the same manner as in Example 1 for preparing the rolled electrode film.

The electrode film was attached to the electrode substrate in the same manner as in Example 2 except that the prepared roll electrode film was used.

Example 5

Run the reel of PET film on the reel rotating drive wheel. A thin (thickness: 100 nm) silver film (metal layer) was formed on the surface of the running PET film in the same manner as in Example 1 using a magnetron spraying apparatus.

The prepared web film was placed on the winding tool in the dry box. According to the microgravure method, the film was coated with a 48 wt % solution of octanoic acid alumina having the formula shown below in xylene while the film was being rolled up with a winding tool. The solution was dried to form a hygroscopic material layer having a thickness of 30 μm. The film is wound up on a winding tool to form a web of film.

A roll of film with a layer of hygroscopic material is run on the roll rotating drive wheels. A thin carbon dioxide film (insulating layer, thickness: 20 nm) was formed on the surface of the hygroscopic material layer of the running film using a magnetron spraying device. Thin Mg-Ag film strips (cathode layer, thickness: 200 nm) were formed through a metal mask to prepare an electrode film. Thin Mg-Ag is stretchable along the axial direction of the film. In the same manner as in Example 1, the prepared electrode film was rolled up to prepare a rolled electrode film.

Except for using the prepared roll electrode film, the electrode film was attached to the electrode substrate in the same manner as in Example 2 to prepare an organic electroluminescence element.

Example 6

A thin silver film (metal layer) was formed on the surface of the PET film in the same manner as in Example 1 using a magnetron spraying apparatus. The film with the thin silver film was taken out from the magnetron spraying device, and the surface of the silver layer was coated with a solution containing a thermosetting acrylic resin according to the microgravure method. The solution is dried, and the resin is heated to harden. A hardened resin layer (insulating layer) was formed to have a thickness of 500 nm. Mg-Ag thin film strips were formed on the insulating layer in the same manner as in Example 1 for preparing the electrode thin film. In addition to using the prepared electrode thin film, the electrode thin film was attached to the electrode substrate to prepare an organic electroluminescence element.

Brief description of the drawings

Fig. 1 is a sectional view showing a structural example of a first organic electroluminescence element of the present invention.

Fig. 2 is a sectional view showing a structural example of the first electrode film of the present invention. The thin film is used to prepare the organic electroluminescent element shown in FIG. 1 .

Fig. 3 is a sectional view showing another example of the thin film structure of the first electrode of the present invention.

Fig. 4 is a sectional view showing an example of the structure of the first rolled electrode film of the present invention.

Fig. 5 is an example illustrating a method (first method) of producing the organic electroluminescence element of the present invention.

Fig. 6 is another example illustrating a method (first method) of producing the organic electroluminescent element of the present invention.

Fig. 7 is a cross-sectional view showing an example of the structure of a second organic electroluminescence element of the present invention.

Fig. 8 is a sectional view showing an example of the thin film structure of the second electrode of the present invention.

Fig. 9 is a sectional view showing another example of the thin film structure of the first electrode of the present invention.

Fig. 10 is a sectional view showing another example of the film structure of the second electrode of the present invention.

parts list

11 Organic electroluminescence element

12 transparent substrate

15 anode layer

16 hole transport layer

17 Light-emitting organic material layer

20 roll electrode film

21 electrode film

22 resin film

23 metal layer

24 insulation layer

25 cathode layer

29 Hygroscopic material layer

31 electrode film

33 metal layer

34 insulation layer

50 substrate transfer film

51 electrode substrate

52 transparent substrate

55 anode layer

56 organic material layer

57a heated roll

57b heating roll

58 Organic electroluminescent elements

59 Arrow indicating the direction of the transmission electrode film

60 roll electrode substrate

61 electrode substrate

62 resin film

65 anode layer

66 organic material layers

68 Organic electroluminescence element

71 Organic electroluminescence element

81 electrode film

91 electrode film

101 electrode film

Claims (3)

1. The method for preparing organic electroluminescent element, described method comprises the following steps: preparing a positive electrode substrate, the positive electrode substrate comprising a transparent substrate, a transparent positive electrode formed on the transparent substrate, and a light-emitting organic material layer formed on the positive electrode; A roll of negative electrode film comprising an outer resin film, a metal layer formed on the resin film, and an inner opaque negative electrode layer formed on the metal layer via an insulating layer is prepared, the roll of negative electrode film The film is wound around a metal core tube or a core tube wrapped with a metal film at a tension of 2.5×10 ⁵ -4.0×10 ⁷ N/m ² in a vacuum or an inert gas atmosphere; Unwind the negative electrode film from the roll; disposing the expanded negative electrode film on the positive electrode substrate, with the proviso that the negative electrode layer is disposed on the light emitting organic material layer; and The negative electrode film was pressed against the positive electrode substrate using heated rollers, thereby attaching the negative electrode film to the positive electrode substrate. 2. The method of claim 1, wherein the negative electrode layer is formed of a metal having a work function of 4 eV or less. 3. The method of claim 1, wherein the negative electrode layer is formed of Mg-Ag.

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