JP2009037799A - Light-emitting element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element excellent in inter-layer adhesion of multilayer sealing films, high sealing function, and of long life. <P>SOLUTION: The light-emitting element has a light-emitting layer on a base board sealed with multilayer sealing films, and at least one adhesion improving layer contained in lamination of the multilayer sealing films. It is preferable to form a multilayer sealing film with at least one first film and at least one second film laminated, and the adhesion improving layer may be formed between at least one first film and at least one second film. The first film and the second film may be organic films, respectively, or inorganic films. If they are both organic films, it is preferable to provide an inorganic film as a third film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device typified by an organic EL device (organic electroluminescence device) and a method for producing the same, and more specifically, to improve interlayer adhesion of a multilayer sealing film that seals a light emitting layer. The present invention relates to a light emitting device and a method for manufacturing the same that improve the device lifetime.

  In light emitting elements such as organic EL elements and light emitting diode display elements, a light emitting layer sandwiched between an anode and a cathode is laminated on a substrate, and a multilayer sealing film is laminated so as to cover the light emitting layer. In a conventional light emitting device, a glass substrate is used as a substrate. However, in order to meet the demands of lightening the device, improving impact resistance, increasing the area of the device, and increasing the efficiency of manufacturing, a plastic substrate is used. It has begun to be used (for example, Patent Document 1).

  The plastic substrate is flexible and can be easily obtained in a large area, and the cutting work for dividing the light emitting layer into units after the lamination is facilitated. However, the plastic substrate has higher gas and liquid permeability than the glass substrate. Display materials such as the organic EL light-emitting layer encapsulated by the substrate and the upper multilayer sealing film are easily oxidized and easily deteriorated by contact with water. Therefore, when using a plastic substrate, a lower sealing film having a high barrier property against gas and liquid is laminated on the substrate, and then a light emitting layer is laminated on the lower multilayer sealing film, and the laminated light emitting layer An upper multilayer sealing film is laminated so as to cover the surface.

  The lower sealing film is usually formed with the same configuration and the same material as the upper multilayer sealing film. These lower multilayer sealing film and upper multilayer sealing film usually have at least one inorganic film and at least one organic film, but in some cases, they may be formed by laminating only inorganic films. The number of layers is determined as necessary. In the case where the number of layers is composed of an organic film and an inorganic film, the inorganic film and the organic film are basically stacked alternately.

  Light extraction from the light emitting element may be performed from the substrate side, from the upper multilayer sealing film side, or from both the substrate side and the upper multilayer sealing film side. The type of light emitting element that extracts light from the substrate side is called a bottom emission type light emitting element, and the type of light emitting element that extracts light from the upper multilayer sealing film side is called a top emission type light emitting element. This light emitting element is called a dual emission type light emitting element. In these types of light emitting elements, the common thing to say is that the multilayer sealing film on the light extraction side needs to be transparent or translucent, and the light extraction efficiency is affected by its physical characteristics. It is. Therefore, in the conventional light emitting device, the multilayer sealing film on the light extraction side is made of a flat layer that is as transparent as possible.

Special table 2003-53745 gazette

  As is well known, when a light emitting layer in a light emitting element comes into contact with oxygen or moisture, the light emitting characteristics of the light emitting layer deteriorate in a relatively short time. Therefore, as disclosed in the prior art, the light emitting layer is sealed with a multilayer sealing film in which an organic film and an inorganic film are stacked in multiple layers.

  As described above, the multilayer sealing film is formed not only from an inorganic film having high sealing performance but also from an alternate lamination with an organic film in order to ensure flexibility in addition to the sealing performance of the film. is there. In such a multilayer sealing film composed of an organic film and an inorganic film, the adhesion at the interface between different materials (mainly the interface between the organic film and the inorganic film) tends to be insufficient. When the manufacturing process is further insufficient or over time, air (oxygen and moisture) easily enters the light emitting layer from the outside, which may shorten the device life.

  The present invention has been made in view of the above-described conventional circumstances, and its object is to provide a light-emitting element that has excellent interlayer adhesion of a multilayer sealing film, has high sealing performance, and has a long lifetime. It is in.

  In order to solve the above problems, a light-emitting device according to the present invention is a light-emitting device having a light-emitting layer on a substrate, and the light-emitting layer is sealed with a multilayer sealing film. It is characterized in that at least one adhesion improving layer is included in the lamination.

  The light-emitting device according to the present invention is a method for manufacturing a light-emitting device having a light-emitting layer on a substrate, and the light-emitting layer is sealed with a multilayer sealing film. At least one adhesion improving layer is formed.

  In the above configuration, the multilayer sealing film is formed by laminating at least one first film and at least one second film, and the at least one first film and at least one second film. It is preferable to form the adhesion improving layer between the two.

  In the above structure, both the first film and the second film may be inorganic films, the first film may be an organic film, and the second film may be an inorganic film. . Further, both the first film and the second film may be organic films. In this case, it is preferable to form at least one third film made of an inorganic film.

  In the above configuration, the adhesion improving layer may be formed using a crosslinked polymer compound, or may be formed using a silane coupling agent.

  The said structure WHEREIN: The said bridge | crosslinking polymer compound may be obtained by applying energy to a polymerizable compound, may be obtained by applying energy to two or more kinds of polymerizable compounds, or at least one kind or more of them. It may be obtained by applying energy to a mixture containing an organic compound and at least one polymerizable compound.

  In the above configuration, a polymerizable compound having eight or more crosslinking groups may be used as the polymerizable compound, and in that case, the crosslinking group is preferably an acrylate.

  As a compounding quantity of the polymeric compound with respect to the said mixture, it is preferable to set suitably in the range of 10-40 mass%.

  In the present invention, the interlayer adhesion of the multilayer sealing film is improved, which is particularly effective when a flexible substrate is used as the substrate. Further, since the sealing characteristics of the sealing film are improved, it is particularly effective when applied to an organic EL element whose light emission characteristics are likely to be deteriorated by contact with oxygen and moisture.

  Further, in the present invention, the adhesion improving layer provided during the lamination of the multilayer sealing film does not particularly deteriorate the transparency of the sealing film. Therefore, the present invention also applies to a light emitting device having a bottom emission structure. The present invention can be similarly applied to a light emitting element having a top emission structure and a light emitting element having a dual emission structure.

  The light emitting device and the manufacturing method thereof according to the present invention can improve the interlayer adhesion of the multilayer sealing layer sealing the light emitting layer of the light emitting device, thereby providing a light emitting device having a long life. There is an effect that can be.

  Below, the light emitting element concerning this invention and its manufacturing method are demonstrated in more detail. First, materials constituting the multilayer sealing layer will be described, and then materials constituting the adhesion improving layer will be described.

(Constituent material of lower and upper multilayer sealing films)
As the inorganic layer constituting the lower and upper multilayer sealing films, materials such as silicon oxide (SiO ₂ ), silicon nitride (SiN), silicon oxynitride (SiON), and aluminum oxide (Al ₂ O ₃ ) are preferably used. Used. As a method for forming the inorganic film, a known thin film forming method such as a sputtering method or a plasma CVD method can be used. In addition, in the multilayer sealing film used for this invention, the layer which consists of inorganic films is called an inorganic layer.

  On the other hand, as the organic layer constituting the lower and upper multilayer sealing films, mainly an organic monomer having a (meth) acryl group having good adhesion to the inorganic layer material, that is, a (meth) acrylic compound is polymerized. The acrylic polymer formed is preferably used. In addition, although these acrylic compounds have favorable adhesiveness with the said inorganic material among organic compounds, it is difficult to make it sufficient. Therefore, in the present invention, as described later, when the adhesion improving layer contains a silane coupling agent with high physical adhesion or when the adhesion improving layer is formed from only one kind of acrylic compound, A similar acrylic compound having 8 or more cross-linking groups and a highly cross-linkable acrylic compound capable of obtaining an effect of improving the adhesion by the close interaction between adjacent films is used. Moreover, in the multilayer sealing film used for this invention, the layer which consists of organic films is called organic layer.

  The (meth) acrylic compound is formed into a coating film by a known coating film forming method such as a solution coating method or a spray coating method, and light energy (chemical rays such as electron beam, plasma beam, ultraviolet ray) is applied to the coating film. It polymerizes by irradiating or applying thermal energy to obtain an acrylic polymer.

  The (meth) acrylic compound is not particularly limited as long as it is a compound containing one or more (meth) acrylic groups in the molecule. When there is one (meth) acryl group, higher adhesion to the inorganic film can be obtained. When the number is two or three, the crosslink density is high, and the film strength of the organic layer is higher.

  Examples of the (meth) acrylic compound include compounds having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) ) Acrylates, compounds having amino groups such as diethylaminoethyl (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloisooxyethyl succinic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, etc. It has a cyclic skeleton such as a compound having a carboxyl group, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate ( Acrylate), isoamyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol ( Acrylic monofunctional compounds such as (meth) acrylate, diethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, 1,9-nonanediol di (meth) ) Acrylate, triethylene di (meth) acrylate, PEG # 200 di (meth) acrylate, PEG # 400 di (meth) acrylate, PEG # 600 di (meth) acrylate, neo Bifunctional (meth) acrylic compounds such as bifunctional urethane (meth) acrylates, such as bifunctional epoxy (meth) acrylates, bifunctional acrylic (meth) acrylates, etc., such as ntil di (meth) acrylate and dimethylol tricyclodecane di (meth) acrylate Can be mentioned. Examples of the compound having three or more (meth) acrylic acids include dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane triacrylate, and trimethylol. An acrylic polyfunctional monomer such as propanetetraacrylate, (meth) acryl polyfunctional epoxy acrylate, (meth) acryl polyfunctional urethane acrylate, and the like can be used.

  The thickness of the organic layer and the inorganic layer constituting the lower and upper multilayer sealing films is preferably in the range of 50 to 10 μm. When the thickness is less than 50 mm, it is difficult to maintain the mechanical properties of the film well. When the thickness exceeds 10 μm, the entire film thickness is increased. In an organic EL element or the like, the light extraction efficiency from the light emitting layer is affected. In some cases.

(Material for improving the adhesion of the adhesion improving layer)
Examples of the material for improving the adhesion include a crosslinked polymer compound and a silane coupling agent as described above.
First, as the crosslinked polymer compound, a monomer compound (polymerizable compound) having a substituent capable of being polymerized by application of thermal energy or light energy and the action of a thermal polymerization initiator or a photopolymerization initiator is converted into a crosslinked polymer. The thing which was done is mentioned. A polymerizable substituent (sometimes referred to as a crosslinking group) refers to a substituent that can form a compound by forming a bond between two or more molecules by causing a polymerization reaction. Examples of such a crosslinking group include a vinyl group, an acetylene group, a butenyl group, an acrylic group, an acrylate group, an acrylamide group, a methacryl group, a methacrylate group, a methacrylamide group, a vinyl ether group, a vinylamino group, a silanol group, and a small ring ( For example, a group having a cyclopropyl group, a cyclobutyl group, an epoxy group, an oxetane group, a diketene group, an episulfide group, or the like, a lactone group, a lactam group, or a group containing a siloxane derivative.

  In addition to the above groups, combinations of groups capable of forming an ester bond or an amide bond can also be used. For example, a combination of an ester group and an amino group, an ester group and a hydroxyl group, or the like.

  Moreover, the material which shows physical adsorptivity to an interface like a silane coupling agent is also mentioned.

  Among the above materials, a monomer having a (meth) acrylate group is particularly preferable. Specific examples of the monofunctional monomer having a (meth) acrylate group include 2-ethylhexyl carbitol acrylate and 2-hydroxyethyl acrylate. Specific examples of the bifunctional monomer having a (meth) acrylate group include 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and triethylene glycol. Examples include di (meth) acrylate and 3-methylpentanediol di (meth) acrylate. Specific examples of other polyfunctional monomers having a (meth) acrylate group include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol penta (meth). Examples thereof include acrylate, dipentaerythritol hexa (meth) acrylate, and trispentaerythritol octa (meth) acrylate. Among them, a polyfunctional monomer having two or more functions, preferably five or more functions, and more preferably eight or more functions is excellent in curability and adhesion, and is preferably used. Here, the “number of functionalities” means the “number of crosslinking groups” described above. That is, the functional group of the polyfunctional monomer means a crosslinking group that the monomer has.

  In addition, about the crosslinking agent used for the said superposition | polymerization, it describes in the 17th-56th pages of a photopolymer handbook (Industry Research Society publication, 1989), for example.

  Moreover, when the above-mentioned material has a fluorine atom, the water repellent effect also acts and the barrier property of the sealing film can be improved.

  As described above, the present invention is characterized in that an adhesion improving layer is provided in the layer of the multilayer sealing film of the light emitting element. It should be noted that this technical idea enables the multilayer sealing film to be configured in addition to improving the interlayer adhesion of the multilayer sealing film. The new structure of the multilayer sealing film is that two or more organic films having different cross-linking degrees can be successively stacked with an adhesion improving layer interposed therebetween. The characteristic of this configuration is that the degree of crosslinking is high and the sealing properties are excellent, but the organic film having poor flexibility and the organic film having low degree of crosslinking and excellent flexibility but poor sealing properties are combined together to form a seal. An organic film having excellent sealing properties and flexibility can be formed in the multilayer sealing film. It is possible to obtain an organic film excellent in sealing property and flexibility by enhancing the adhesiveness of two organic films having insufficient adhesion between each other due to different degrees of cross-linking with an adhesion improving layer. it can.

  In the present invention, the material monomer when the adhesion improving layer is composed of a crosslinked polymer compound is an acrylic polymerizable compound similar to the organic film used in the conventional multilayer sealing film. As described above, those having a larger number of crosslinking groups than the acrylic polymerizable compounds used in conventional organic films are selectively used.

As described above, in the light emitting device of the present invention, a configuration in which an organic film is newly formed can be formed by providing an adhesion improving layer during the lamination of the multilayer sealing film. In addition, various combinations are possible as the laminated structure of the multilayer sealing film. As described above, when the adhesion improving layer is composed of a crosslinked polymer compound, the composition can be roughly divided into a case where one kind of polymerizable compound is cured, and an organic compound and a polymerizable compound. In some cases, a mixture with a compound or a mixture of two or more polymerizable compounds is cured. When the former is the adhesion improving layer A and the latter is the adhesion improving layer B, the following six types of the multilayer sealing film can be considered (in the present invention, the adhesion improving layer is a physical adhesion). There is also an adhesion improving layer C constituted by using a silane coupling agent which is an improving material).
(1) Inorganic film / adhesion improving layer A / inorganic film (2) Organic film / adhesion improving layer A / inorganic film (3) Organic film / adhesion improving layer A / organic film (4) Inorganic film / adhesiveness Improvement layer B / Inorganic film (5) Organic film / Adhesion improvement layer B / Inorganic film (6) Organic film / Adhesion improvement layer B / Organic film

  In the present invention, in the laminated structure of (1), (2) and (3) above, the polymerizable compound used is a substituent having an interaction with an adjacent film using a polymerizable compound having 8 or more crosslinking groups. It is preferable to increase the number to further improve the adhesion with the adjacent film.

  The light emitting device and the method for manufacturing the light emitting device according to the present invention having the above-described configuration are particularly useful when the light emitting device is an organic EL device. Also in such an organic EL element, the configuration of the multilayer sealing film described in detail above is the same. Therefore, other main components such as a substrate and a light emitting layer in the organic EL element to which the present invention can be suitably applied will be described in detail below.

(substrate)
The substrate used for the organic EL element may be any substrate that does not change when the electrode is formed and the organic layer is formed. For example, glass, plastic, polymer film, silicon substrate, or a laminate of these is used. It is done.

(Electrode and light emitting layer)
As a basic structure of the organic EL element, at least one light emitting layer is provided between an electrode composed of a pair of an anode (first electrode) and a cathode (second electrode) in which at least the cathode is transparent or translucent with light transmission. Have For the light emitting layer, a low molecular weight and / or high molecular weight organic light emitting material is used.

  In the organic EL element, examples of components around the light emitting layer include those provided between the cathode and the light emitting layer and those provided between the anode and the light emitting layer as layers other than the cathode, the anode, and the light emitting layer. Examples of the material provided between the cathode and the light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer.

  The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode, and the electron transport layer is a layer having a function of improving electron injection from the electron injection layer or the electron transport layer closer to the cathode. is there. When the electron injection layer or the electron transport layer has a function of blocking hole transport, these layers may be referred to as a hole blocking layer. Having the function of blocking hole transport makes it possible, for example, to produce an element that allows only hole current to flow, and confirm the blocking effect by reducing the current value.

  Examples of what is provided between the anode and the light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer.

  The hole injection layer is a layer having a function of improving the hole injection efficiency from the cathode, and the hole transport layer improves the hole injection from the hole injection layer or the hole transport layer closer to the anode. This is a functional layer. In addition, when the hole injection layer or the hole transport layer has a function of blocking electron transport, these layers may be referred to as an electron block layer. Having the function of blocking electron transport makes it possible, for example, to manufacture an element that allows only electron current to flow and to confirm the blocking effect by reducing the current value.

Various combinations around the light emitting layer as described above include a structure in which a hole transport layer is provided between the anode and the light emitting layer, a structure in which an electron transport layer is provided between the cathode and the light emitting layer, and a cathode and light emission. Examples include a configuration in which an electron transport layer is provided between the layers and a hole transport layer is provided between the anode and the light emitting layer. For example, the following structures a) to d) are specifically exemplified.
a) Anode / light emitting layer / cathode b) Anode / hole transport layer / light emitting layer / cathode c) Anode / light emitting layer / electron transport layer / cathode d) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (Here, / indicates that each layer is laminated adjacently. The same shall apply hereinafter.)

  Here, as described above, the light emitting layer is a layer having a function of emitting light, the hole transporting layer is a layer having a function of transporting holes, and the electron transporting layer has a function of transporting electrons. It is a layer having. The electron transport layer and the hole transport layer are collectively referred to as a charge transport layer. Two or more light emitting layers, hole transport layers, and electron transport layers may be used independently. Further, among the charge transport layers provided adjacent to the electrodes, those having a function of improving the charge injection efficiency from the electrodes and having the effect of lowering the driving voltage of the element are particularly charge injection layers (hole injection layers). , An electron injection layer).

  Furthermore, in order to improve the adhesion with the electrode or the improvement of charge injection from the electrode, the charge injection layer or the insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode, and the adhesion at the interface may be increased. In order to improve or prevent mixing, a thin buffer layer may be inserted at the interface between the charge transport layer and the light emitting layer. The order and number of layers to be laminated, and the thickness of each layer can be appropriately used in consideration of light emission efficiency and element lifetime.

Moreover, as an organic EL element provided with a charge injection layer (electron injection layer, hole injection layer), an organic EL element provided with a charge injection layer adjacent to the cathode, and a charge injection layer provided adjacent to the anode. An organic EL element is mentioned. For example, the following structures e) to p) are specifically mentioned.
e) Anode / charge injection layer / light emitting layer / cathode f) Anode / light emitting layer / charge injection layer / cathode g) Anode / charge injection layer / light emitting layer / charge injection layer / cathode h) Anode / charge injection layer / hole Transport layer / light emitting layer / cathode i) anode / hole transport layer / light emitting layer / charge injection layer / cathode j) anode / charge injection layer / hole transport layer / light emitting layer / charge injection layer / cathode k) anode / charge Injection layer / light emitting layer / charge transport layer / cathode l) anode / light emitting layer / electron transport layer / charge injection layer / cathode m) anode / charge injection layer / light emitting layer / electron transport layer / charge injection layer / cathode n) anode / Charge injection layer / hole transport layer / light emitting layer / charge transport layer / cathode o) anode / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode p) anode / charge injection layer / hole transport Layer / light emitting layer / electron transport layer / charge injection layer / cathode

(anode)
For the anode, for example, as a transparent electrode or a semitransparent electrode, a metal oxide, metal sulfide or metal thin film with high electrical conductivity can be used, and a high transmittance can be suitably used. Are appropriately selected and used. Specifically, indium oxide, zinc oxide, tin oxide, and a composite film made of conductive glass made of indium / tin / oxide (ITO), indium / zinc / oxide, etc. (NESA) Etc.), gold, platinum, silver, copper and the like are used, and ITO, indium / zinc / oxide, and tin oxide are preferable. Examples of the production method include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Further, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used as the anode.

  The film thickness of the anode can be appropriately selected in consideration of light transmittance and electrical conductivity, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, more preferably 50 nm to 500 nm. is there.

(Hole injection layer)
As described above, the hole injection layer can be provided between the anode and the hole transport layer or between the anode and the light emitting layer. Materials for forming the hole injection layer include phenylamine, starburst amine, phthalocyanine, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide and other oxides, amorphous carbon, polyaniline, polythiophene derivatives, etc. It is done.

(Hole transport layer)
Materials constituting the hole transport layer include polyvinyl carbazole or derivatives thereof, polysilane or derivatives thereof, polysiloxane derivatives having aromatic amines in the side chain or main chain, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine. Derivatives, polyaniline or derivatives thereof, polythiophene or derivatives thereof, polyarylamine or derivatives thereof, polypyrrole or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof, etc. Is exemplified.

  Among these, as a hole transport material used for the hole transport layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Polymeric hole transport materials such as polythiophene or derivatives thereof, polyarylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferred, and more preferred Is polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in a side chain or a main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

(Light emitting layer)
In the present invention, the light emitting layer is an organic light emitting layer, and usually has organic substances (low molecular compounds and high molecular compounds) that mainly emit fluorescence or phosphorescence. Further, a dopant material may be included. Examples of the material for forming the light emitting layer that can be used in the present invention include the following.

(Light-emitting layer forming material 1: dye-based material)
Examples of dye-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, and the like.

(Light emitting layer forming material 2: metal complex material)
Examples of the metal complex material include metal complexes that emit light from triplet excited states such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, azomethyls. Zinc complex, porphyrin zinc complex, europium complex, etc., which has Al, Zn, Be or the like as the central metal or rare earth metal such as Tb, Eu, or Dy, and the ligand is oxadiazole, thiadiazole, phenylpyridine, phenylbenzo Examples thereof include metal complexes having an imidazole or quinoline structure.

(Light-emitting layer forming material 3: polymer material)
Polymeric materials include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polymerized chromophores and metal complex light emitting materials. Etc.

  Examples of the material that emits blue light among the light emitting layer forming materials include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

  Examples of the light emitting layer forming material that emits green light include quinacridone derivatives, coumarin derivatives, polymers thereof, polyparaphenylene vinylene derivatives, and polyfluorene derivatives. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

  Examples of the material that emits red light among the light emitting layer forming materials include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.

(Light-emitting layer forming material 4: dopant material)
A dopant can be added to the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like.

(Electron transport layer)
As the material for forming the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquinodi. Examples include methane or derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene or derivatives thereof, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof, and the like. The

  Of these, oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof are preferred, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are more preferable.

(Electron injection layer)
As described above, the electron injection layer is provided between the electron transport layer and the cathode, or between the light emitting layer and the cathode. Depending on the type of the light emitting layer, the electron injection layer is an electron injection layer having a single layer structure of Ca layer, or a metal of group IA and IIA of the periodic table excluding Ca and having a work function of 1. It is possible to provide an electron injection layer having a laminated structure of a Ca layer and a layer formed of one or more of 5-3.0 eV metal and oxides, halides and carbonates of the metal. . Examples of metals of Group IA of the periodic table having a work function of 1.5 to 3.0 eV or oxides, halides, and carbonates thereof include lithium, lithium fluoride, sodium oxide, lithium oxide, lithium carbonate, and the like. Can be mentioned. Examples of metals of Group IIA of the periodic table excluding Ca having a work function of 1.5 to 3.0 eV or oxides, halides and carbonates thereof include strontium, magnesium oxide, magnesium fluoride, fluorine Strontium fluoride, barium fluoride, strontium oxide, magnesium carbonate and the like.

(cathode)
For the cathode, as transparent or semi-transparent electrode, metal, graphite or graphite intercalation compound, inorganic semiconductor such as ZnO (zinc oxide), ITO (indium tin oxide), IZO (indium zinc zinc oxide), etc. And conductive oxides such as strontium oxide and barium oxide. Examples of the metal include alkali metals such as lithium, sodium, potassium, rubidium and cesium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium, gold, silver, platinum, copper, manganese, titanium, cobalt, Transition metals such as nickel and tungsten; tin, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium; and alloys of two or more thereof. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, and the like. The cathode may have a laminated structure of two or more layers. Examples of this include a laminated structure of the above metals, metal oxides, fluorides, alloys thereof, and metals such as aluminum, silver, and chromium.

  Examples of the present invention will be described below. The following examples are preferred examples for explaining the present invention, and do not limit the present invention. In the following examples, an organic EL element is assumed as a light emitting element. The present invention is particularly effective in the case of an organic EL element, but is similarly effective in other light emitting elements.

  In the organic EL elements of the following examples, as described above, the electrode elements are most simply composed of only an anode and a cathode, and these are laminated on both sides of the light emitting layer to form a light emitting portion. In addition to the anode and cathode, other electrode elements such as a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer may be combined in various combinations and stacked on the light emitting layer. Thus, a light emitting part may be formed. In the following examples, the electrode elements formed on both sides of the light emitting layer are simply described, but it is obvious that the present invention can be similarly applied to any configuration of electrode elements stacked on the light emitting layer. is there. That is, after various combinations of electrode elements are laminated on the light emitting layer, a multilayer sealing film is laminated thereon. In the present invention, the light emitting layer is sealed with the multilayer sealing film means the above-described configuration.

Example 1
(Method for producing organic EL element)
A glass substrate on which ITO (transparent electrode) with a film thickness of about 150 nm formed by sputtering is patterned is washed with an organic solvent, an alkaline detergent, and ultrapure water and dried. This substrate is subjected to UV-O ₃ treatment (lyophilic treatment) using a UV-O ₃ apparatus (trade name “Model 312 UV-O ₃ Cleaning System” manufactured by Technovision Co., Ltd.).

  A suspension of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (trade name “Bytron P TP AI 4083” manufactured by HC Starck B-Tech Co., Ltd.) is filtered through a 0.5 μm filter on the ITO side of the substrate. Then, the suspension is formed into a film with a thickness of 70 nm by spin coating, and dried on the hot plate at 200 ° C. for 10 minutes in the air.

  Next, a 1.5 wt% solution of a polymer organic light-emitting material (trade name “Lumation GP1300” manufactured by Cymation Co., Ltd.) is prepared using a solvent in which xylene and anisole are mixed 1: 1. This solution is deposited to a thickness of 80 nm on a substrate on which “Bytron P” has been deposited, using spin coating.

The light emitting layer in the extraction electrode part and the sealing area part is removed, introduced into a vacuum chamber, and transferred to a heating chamber (hereinafter, the process is performed in vacuum or in nitrogen, and the device in the process is not exposed to the atmosphere. .) Next, heating is performed in a vacuum (degree of vacuum is 1 × 10 ⁻⁴ Pa or less) at a temperature of about 100 ° C. for 60 minutes.

  Thereafter, the substrate is transferred to the vapor deposition chamber, aligned with the cathode mask, and vapor-deposited so that the cathode is formed on the light emitting portion and the extraction electrode portion. The cathode heats Ba metal by a resistance heating method, deposits it at a deposition rate of about 2 mm / sec and a film thickness of 50 mm, and uses an electron beam deposition method to deposit Al at a deposition rate of about 2 mm / sec and a film thickness of 1500 mm. Vapor deposition is performed.

(Formation of organic / inorganic multilayer sealing film)
After the device is created, the substrate is transferred to a film sealing device (trade name “Guardian 200” manufactured by VITEX, USA) without being exposed to the atmosphere from the vapor deposition chamber. Align and set the mask on the substrate. Next, the substrate is moved to the inorganic film formation chamber, and aluminum oxide which is the first inorganic layer is formed by sputtering. Argon gas and oxygen gas are introduced using an Al metal target having a purity of 5N, and an aluminum oxide film is formed on the substrate. A transparent and flat aluminum oxide film having a thickness of about 60 nm is obtained.

  After forming the first inorganic layer, the inorganic layer mask is removed, replaced with an organic layer mask, and transferred to the organic film forming chamber. TPEA (trispentaerythritol octaacrylate) (manufactured by Koei Chemical Co., Ltd.), an organic monomer material (made by VITEX, trade name “Vitex Barix Resin System monomer material (Vitex 701)”) and an octafunctional acrylate as a material for improving adhesion Is added to the vaporizer, vaporized, and the monomer vapor containing the adhesion improver is ejected from the slit nozzle, and the substrate passes through the nozzle at a constant speed to achieve a uniform thickness. The monomer is attached to the substrate so that Next, the substrate to which the monomer is attached is irradiated with UV light to crosslink and cure the monomer, thereby forming a first organic layer (adhesion improving layer). The obtained film is a transparent and flat film, and the film thickness is about 1.3 μm.

After forming the first organic layer (adhesion improving layer), the substrate is transferred to the inorganic film formation chamber, and argon and oxygen are introduced, and the second oxide layer, aluminum oxide, is formed by sputtering. A transparent and flat aluminum oxide film having a thickness of about 40 nm is formed. A transparent and flat aluminum oxide film having a thickness of about 40 nm is formed. After the second inorganic layer is formed, the second organic layer (adhesion improving layer) is formed in the same manner as the first organic layer, and after the second organic layer is formed, the same as the second inorganic layer Thus, the third inorganic layer is formed. Similarly, a third organic layer (adhesion improving layer) and a fourth inorganic layer are formed to obtain a multilayer sealing film.
In the configuration of the multilayer sealing film of the above embodiment, the first inorganic layer and the second inorganic layer correspond to the first film and the second film defined in the present invention, respectively. Similarly, the relationship between the second inorganic layer and the third inorganic layer also corresponds to the first film and the second film defined in the present invention, respectively, and further, the third inorganic layer and the fourth inorganic layer The relationship with the layers also corresponds to the first film and the second film defined in the present invention, respectively. And the adhesion improvement layer (a 1st organic layer, a 2nd organic layer, and a 3rd organic layer) is formed between each inorganic layer, and the adhesiveness between each inorganic layer is improved.

(Comparative Example 1)
An organic EL device is obtained in the same manner as in Example 1 except that the adhesion improver (trispentaerythritol octaacrylate) was not added to the organic monomer material forming the organic layer in Example 1.

(Evaluation of interlayer adhesion of multilayer sealing film)
The interlayer adhesion of the multilayer sealing film of the organic EL device produced in the above Examples and Comparative Examples is evaluated by the following method.

(Evaluation methods)
An operation in which Nichiban cellophane tape is applied to the 100 squares produced by 11 lines each vertically and horizontally on the multilayer sealing film formed on the organic EL element, and peeled off at a stretch vertically. Evaluation is performed by repeating three times and measuring the number of peeled eyes.

  In the above embodiment, each organic layer of the multilayer sealing film is formed by containing a material that improves adhesion, but a material that directly improves adhesion at the interface of each inorganic layer of the multilayer sealing film is used. The adhesion improving layer may be formed between the inorganic layer and the organic layer by applying and curing the coating film.

  As described above, the light-emitting element and the manufacturing method thereof according to the present invention can improve the interlayer adhesion of the multilayer sealing layer that seals the light-emitting layer of the light-emitting element. There exists an effect that an element can be provided.

Claims (30)

A light-emitting element having a light-emitting layer on a substrate, the light-emitting layer being sealed with a multilayer sealing film,
A light emitting device comprising at least one adhesion improving layer in the multilayer sealing film.   The multilayer sealing film has at least one first film and at least one second film, and the adhesion between the at least one first film and the at least one second film. The light emitting device according to claim 1, further comprising an improvement layer.   The light emitting element according to claim 2, wherein both the first film and the second film are inorganic films.   The light-emitting element according to claim 2, wherein the first film is an organic film and the second film is an inorganic film.   3. The light emitting device according to claim 2, wherein both the first film and the second film are organic films, and further includes at least one third film made of an inorganic film.   The light-emitting element according to claim 1, wherein the adhesion improving layer contains a crosslinked polymer compound.   The light-emitting device according to claim 6, wherein the crosslinked polymer compound is obtained by applying energy to a polymerizable compound.   The light-emitting device according to claim 6, wherein the cross-linked polymer compound is obtained by applying energy to two or more kinds of polymerizable compounds.   The light-emitting element according to claim 6, wherein the crosslinked polymer compound is obtained by applying energy to a mixture containing at least one organic compound and at least one polymerizable compound.   The light-emitting element according to claim 7, wherein the polymerizable compound has eight or more cross-linking groups.   The light-emitting element according to claim 10, wherein the cross-linking group is an acrylate.   The light emitting device according to any one of claims 9 to 11, wherein the weight of the polymerizable compound is 10 to 40 when the weight of the mixture is 100.   The light-emitting element according to claim 1, wherein the adhesion improving layer contains a silane coupling agent.   The light emitting device according to claim 1, wherein the substrate is a flexible substrate.   It is an organic EL element, The light emitting element of any one of Claims 1-14 characterized by the above-mentioned. A method for producing a light emitting device having a light emitting layer on a substrate, wherein the light emitting layer is sealed with a multilayer sealing film,
A method for manufacturing a light-emitting element, comprising forming at least one adhesion improving layer in the multilayer sealing film.   The multilayer sealing film is formed by laminating at least one first film and at least one second film, and between the at least one first film and at least one second film. The method for manufacturing a light emitting device according to claim 16, wherein the adhesion improving layer is formed.   The method for manufacturing a light-emitting element according to claim 17, wherein both the first film and the second film are inorganic films.   The method for manufacturing a light-emitting element according to claim 17, wherein the first film is an organic film and the second film is an inorganic film.   18. The method for manufacturing a light emitting element according to claim 17, wherein the first film and the second film are organic films, and at least one third film made of an inorganic film is formed.   21. The method for manufacturing a light-emitting element according to claim 16, wherein the adhesion improving layer is formed using a crosslinked polymer compound.   The method for producing a light emitting device according to claim 21, wherein the crosslinked polymer compound is obtained by applying energy to a polymerizable compound.   The method for producing a light emitting device according to claim 21, wherein the crosslinked polymer compound is obtained by applying energy to two or more kinds of polymerizable compounds.   The method for producing a light emitting device according to claim 21, wherein the crosslinked polymer compound is obtained by applying energy to a mixture containing at least one organic compound and at least one polymerizable compound.   The method for producing a light-emitting element according to any one of claims 22 to 24, wherein a polymerizable compound having eight or more crosslinking groups is used as the polymerizable compound.   26. The method for manufacturing a light emitting device according to claim 25, wherein the crosslinking group is an acrylate.   27. The method for manufacturing a light-emitting element according to any one of claims 24 to 26, wherein a blending amount of the polymerizable compound with respect to the mixture is 10 to 40% by mass.   The method for manufacturing a light-emitting element according to any one of claims 16 to 27, wherein the adhesion improving layer is formed using a silane coupling agent.   The method for manufacturing a light-emitting element according to any one of claims 16 to 28, wherein a flexible substrate is used as the substrate.   30. The method for producing a light-emitting element according to any one of claims 16 to 29, wherein the light-emitting element is an organic EL element.