JP2010045222A - Organic electric field light emitting device, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electric field light emitting device which has a prolonged element life. <P>SOLUTION: For example, the organic electric field light emitting device is constituted by stacking a transparent electrode 12 (positive electrode), a hole injection layer 14, a hole transport layer 16 (second organic compound layer), an intermediate layer 18A, a light emitting layer 20 (first organic compound layer), and a back electrode 24 (negative electrode) in order on a transparent insulator substrate 10. Then the intermediate layer 18A disposed between the hole transport layer 16 and light emitting layer 20 contains a material (for example, a hole transport material) forming the hole transport layer 16 and a material (for example, a light emitting material) forming the light emitting layer 20. The intermediate layer is not limited as above, but may be provided between other organic compound layers, for example, between an electron transport layer and the light emitting layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent element and a display device.

  An organic electroluminescent element (hereinafter referred to as an organic electroluminescent element) has an organic compound layer provided between an anode and a cathode as electrodes, and a voltage is applied between both electrodes to inject holes and electrons into the organic compound layer. The charge injection type light emitting element emits light by recombination of these charges (carriers). The element structure is such that one or more organic compound element layers are sandwiched between both electrodes. Organic electroluminescent devices are self-luminous devices, and active research is being conducted with the aim of applying them to thin large-screen displays that can be driven with high brightness and low voltage.

  Organic electroluminescent elements are classified into elements using low molecular weight materials and elements using polymer materials in terms of the characteristics of organic compounds and the manufacturing process. Low molecular weight materials are mainly formed using a dry process such as a vacuum deposition method. This dry process is advantageous in that it is easy to produce a laminated structure, to easily adjust the film formation rate, and to enable the application of RGB color elements using a mask. In addition, in low molecular weight materials, dye doping is generally performed on the light emitting layer by co-evaporation to improve luminance, light emission efficiency, color purity, and the like (see Patent Documents 1 to 3).

On the other hand, in a polymer material, a wet process such as a spin coating method, an ink jet method, or a printing method can be applied, a film can be formed in the atmosphere, and a large-scale facility is not required. In addition, since low-temperature film formation is possible and material selectivity is widened, realization of a flexible display or the like is expected by forming a film on plastic (see Patent Document 4).
JP 2000-315583 A JP 2001-244079 A JP 2003-229272 A JP 2006-133573 A

  The subject of this invention is providing the organic electroluminescent element which extended the element lifetime compared with the case where an organic compound layer is directly laminated | stacked not via a specific intermediate | middle layer.

The above problem is solved by the following means. That is,
According to the invention of claim 1,
A pair of electrodes consisting of an anode and a cathode, at least one of which is transparent or translucent,
A first organic compound layer disposed between the pair of electrodes;
A second organic compound layer disposed between the pair of electrodes;
It is disposed between the first organic compound layer and the second organic compound layer, and includes a material constituting the first organic compound layer and a material constituting the second organic compound layer. The middle layer,
An organic electroluminescent device comprising:

According to the invention of claim 2,
The first organic compound layer is a light emitting layer;
The second organic compound layer is a charge transport layer;
The intermediate layer is an intermediate layer configured to include a material constituting the light emitting layer and a material constituting the charge transport layer,
The organic electroluminescent element according to claim 1.

According to the invention of claim 3,
The organic electroluminescence device according to claim 1 or 2, arranged in at least one of a matrix shape and a segment shape,
Driving means for driving the organic electroluminescent element;
A display device comprising:

According to the first aspect of the present invention, the device life is extended as compared with the case where the organic compound layer is directly laminated without using a specific intermediate layer.
According to the second aspect of the present invention, the device life is extended as compared with the case where a specific intermediate layer is provided between other organic compound layers.
According to the invention of claim 3, display defects based on the element lifetime of the organic electroluminescent element are suppressed over a long period of time compared with the case where an organic electroluminescent element in which an organic compound layer is directly laminated without using a specific intermediate layer is used. The

  Embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same function throughout all the drawings, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a schematic configuration diagram illustrating an organic electroluminescent element according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating an organic electroluminescent device according to another embodiment. FIG. 3 is a schematic configuration diagram illustrating an organic electroluminescent device according to another embodiment.

  As shown in FIG. 1, the organic electroluminescent device 100 according to this embodiment includes a transparent electrode 12 (anode), a hole injection layer 14, a hole transport layer 16 (second organic compound) on a transparent insulator substrate 10. Layer), the intermediate layer 18A, the light emitting layer 20 (first organic compound layer), and the back electrode 24 (cathode) are sequentially laminated. The intermediate layer 18 </ b> A disposed between the hole transport layer 16 and the light emitting layer 20 constitutes the material (for example, hole transport material) constituting the hole transport layer 16 and the light emitting layer 20. And a material (for example, a light emitting material).

  The organic electroluminescent device 100 according to the present embodiment is not limited to the above configuration, and as shown in FIG. 2, for example, on a transparent insulator substrate 10, a transparent electrode 12 (anode), a hole injection layer 14, a light emitting layer. 20 (first organic compound layer), intermediate layer 18B, electron transport layer 22 (second organic compound layer), and back electrode 24 (cathode) are sequentially laminated. In the case of this embodiment, the intermediate layer 18B disposed between the electron transport layer 22 and the light emitting layer 20 includes a material (for example, an electron transport material) constituting the electron transport layer 22 and the light emitting layer 20. And a material (for example, a light emitting material).

  Of course, as shown in FIG. 3, the organic electroluminescent device 100 according to the present embodiment has a transparent electrode 12, a hole injection layer 14, a hole transport layer 16, an intermediate layer 18 </ b> A, light emission on a transparent insulator substrate 10. The layer 20, the intermediate layer 18B, the electron transport layer 22, and the back electrode 24 are sequentially stacked. And it is good also as intermediate | middle layer 18A, 18B of the structure similar to FIG.1 and FIG.2.

  On the other hand, the display device according to the present embodiment is connected to the organic electroluminescent element 100 and a pair of electrodes (transparent electrode 12 and back electrode 24) of the organic electroluminescent element 100, and a DC voltage is applied between the pair of electrodes. The thing provided with the voltage application apparatus 30 (voltage application means) for applying as a drive means is mentioned.

As a method for driving the organic electroluminescent element 100 using the voltage application device 30, for example, a direct current voltage of 4 mA to 20 V and a current density of 1 mA / cm ^{2 to} 200 mA / cm ² is applied between a pair of electrodes. As a result, the organic electroluminescent device 100 emits light.

  In addition, the organic electroluminescent element 100 according to the present embodiment has been described with respect to the configuration of the minimum unit (one pixel unit). For example, the one pixel unit (organic electroluminescent element) is at least one of a matrix shape and a segment shape. It is applied to the arranged display device. When the organic electroluminescent elements 100 are arranged in a matrix, the electrodes may be arranged in a matrix, or both the electrodes and the organic compound layer may be arranged in a matrix. Moreover, when arrange | positioning the organic electroluminescent element 100 in a segment form in this embodiment, the aspect which arrange | positions only an electrode in a segment form may be sufficient, and the aspect which arrange | positions both an electrode and an organic compound layer in a segment form. There may be.

  In addition, as a driving method of the display device according to the present embodiment, a conventionally known technique, for example, a plurality of row electrodes and column electrodes are arranged, and the row electrodes are scanned according to image information corresponding to each row electrode while being scanned. Simple matrix driving in which electrodes are driven collectively, active matrix driving using pixel electrodes arranged for each pixel, and the like are used.

  In the organic electroluminescent device 100 according to any of the above embodiments, the first organic compound layer such as the light emitting layer 20 and the second organic compound layer such as the charge transport layer (the hole transport layer 16 and the electron transport layer 22), Intermediate layers 18A and 18B are provided between the two. And these intermediate | middle layers 18A and 18B are comprised including the material which comprises a 1st organic compound layer, and the material which comprises a 2nd organic compound layer. That is, the intermediate layers 18A and 18B are mixed layers of two materials. By providing the intermediate layers 18A and 18B having this configuration, it is considered that the electrical barrier generated between the first organic compound layer and the second organic compound layer is reduced. For this reason, the device life is extended as compared with the case where the organic compound layer is directly laminated without using the specific intermediate layers 18A and 18B. That is, for example, an element in which the generation / expansion of a non-light emitting region (dark spot) is suppressed and the initial luminance half-life is extended is obtained. As a result, the display device according to the present embodiment suppresses display defects based on the element lifetime of the organic electroluminescent element over a long period of time.

  In particular, by providing the intermediate layers 18A and 18B between the light emitting layer 20 as the first organic compound layer and the charge transport layer (the hole transport layer 16 and the electron transport layer 22) as the second organic compound layer, It is considered that charge trapping generated at the interface between the light emitting layer 20 and the charge transport layer is suppressed and the charge injection property is improved. For this reason, compared with the case where a specific intermediate layer is provided between other organic compound layers, the generation / expansion of a non-light emitting region (dark spot) is suppressed and the device life is extended.

  Here, in the intermediate layers 18A and 18B, the mixing ratio of the material constituting the first compound layer and the material constituting the second compound layer is preferably in the range of 7: 3 to 3: 7 by weight ratio. Is preferably in the range of 3: 2 to 2: 3.

  Of course, other than between the light emitting layer 20 and the charge transport layer (the hole transport layer 16 and the electron transport layer 22), for example, between other organic compound layers such as between the hole injection layer 14 and the hole transport layer 16, An intermediate layer containing a mixture of both materials may be provided.

  Next, it demonstrates in detail with the manufacturing method of the organic electroluminescent element which concerns on this embodiment.

  FIG. 4 is a process diagram showing a method for manufacturing an organic electroluminescent device according to this embodiment. In addition, about the manufacturing method of the organic electroluminescent element which concerns on this embodiment, it shows about the manufacturing method of the organic electroluminescent element which has a layer structure shown in FIG.

First, as shown in FIG. 4A, a transparent insulator substrate 10 is prepared. Here, the transparent insulator substrate 10 is preferably a transparent substrate for taking out light emission, and a glass substrate, a plastic film substrate, or the like is used. Here, the term “transparent” means that the light transmittance in the visible region is 10% or more, and the transmittance is preferably 75% or more. The insulating property means that the volume resistivity is 10 ¹³ Ωcm or more. The same applies hereinafter.

  Next, as shown in FIG. 4B, a transparent electrode 12 is formed on the transparent insulator substrate 10. The transparent electrode 12 is transparent in order to extract emitted light in the same manner as the transparent insulator substrate 10 and preferably has a high work function for injecting holes. For example, an oxide film (for example, indium tin oxide (ITO)) is preferable. , Tin oxide (NESA), indium oxide, zinc oxide, or the like) or metal film (eg, gold, platinum, palladium, or the like) is preferably used. The transparent electrode 12 is formed by, for example, a vapor deposition method or a sputtering method.

  Next, as shown in FIG. 4C, the hole injection layer 14 is formed on the transparent insulator substrate 10 on which the transparent electrode 12 is formed. Examples of the hole injection material constituting the hole injection layer 14 include MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine), copper phthalocyanine, polyaniline, PEDOT / PSS ( Polyethylene dioxythiophene / polystyrene sulfonate) or mixtures thereof are preferably used.

  Here, the hole injection layer 14 is formed by using a coating liquid containing a hole injection material and a solvent for dissolving or dispersing the hole injection material, for example, by forming the film using a spin coating method, a dip method, or the like. Is done.

  Next, as shown in FIG. 4D, the hole transport layer 16 is formed on the transparent insulator substrate 10 on which the hole injection layer 14 is formed. As the hole transport material constituting the hole transport layer 16, a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an aryl hydrazone derivative, a porphyrin-based compound, or the like is desirably used as the hole transport material. . Particularly preferred specific examples include the following exemplary compounds (I-1) to (I-6). In (I-1) to (I-6), n represents an integer of 1 or more.

  Here, the hole transport layer 16 is formed by using a coating liquid containing a hole transport material and a solvent for dissolving or dispersing the hole transport material, and forming the film by, for example, a spray method or an electrospray method. . Of course, the hole transport layer 16 may be formed by film formation using a spin coating method, a dip method or the like.

  Next, as shown in FIG. 4E, an intermediate layer 18A is formed on the transparent insulator substrate 10 on which the hole transport layer 16 is formed. The material composing the intermediate layer 18A is a mixed material of the material composing the hole transport layer 16 (for example, hole transport material) and the material composing the light emitting layer 20 (for example, light emitting material).

  Here, the intermediate layer 18A is formed by using a coating liquid containing a hole transport material and a light emitting material and a solvent for dissolving or dispersing them, and for example, forming the film by a spray method or an electrospray method. The

  Next, as shown in FIG. 4F, the light emitting layer 20 is formed on the transparent insulator substrate 10 on which the intermediate layer 18A is formed. Examples of the light-emitting material constituting the light-emitting layer 20 include compounds that exhibit a higher fluorescence quantum yield in a solid state than other states, and examples thereof include a low-molecular light-emitting material and a polymer light-emitting material. Examples of the low-molecular light-emitting material include chelate-type organometallic complexes, polynuclear or condensed aromatic ring compounds, perylene derivatives, coumarin derivatives, styrylarylene derivatives, silole derivatives, oxazole derivatives, oxathiazole derivatives, or oxadiazole derivatives. Examples of the polymer light emitting material include polyparaphenylene derivatives, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyacetylene derivatives. Preferable specific examples include the following compounds (II-1) to (II-17), but are not limited thereto.

In the compounds (II-1) to (II-17), Ar is a substituted or unsubstituted phenyl group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings. Represents a monovalent condensed aromatic hydrocarbon having 2 or more and 10 or less substituted or unsubstituted aromatic rings, or a substituted or unsubstituted monovalent aromatic heterocyclic ring.
In the compounds (II-1) to (II-17), X represents a substituted or unsubstituted divalent aromatic group. Specifically, X is a substituted or unsubstituted phenylene group, a substituted or unsubstituted divalent polynuclear aromatic hydrocarbon having 2 to 10 aromatics, a substituted or unsubstituted aromatic group having 2 to 10 aromatics. A divalent condensed ring aromatic hydrocarbon, a substituted or unsubstituted divalent aromatic heterocyclic ring, or a substituted or unsubstituted divalent aromatic group containing at least one aromatic heterocyclic ring.
In compounds (II-1) to (II-17), n and x represent an integer of 1 or more, and y represents 0 or 1.

  The polynuclear aromatic hydrocarbon, condensed aromatic hydrocarbon, and aromatic heterocycle are not particularly limited. In addition, the polynuclear aromatic hydrocarbon, the condensed aromatic hydrocarbon, and the aromatic heterocycle in the present embodiment mean specifically defined as follows.

That is, the “polynuclear aromatic hydrocarbon” represents a hydrocarbon in which 2 to 10 aromatic rings composed of carbon and hydrogen are present and the rings are bonded to each other through a carbon-carbon bond. Specific examples include biphenyl and terphenyl.
“Condensed aromatic hydrocarbon” refers to a hydrocarbon in which two or more aromatic rings composed of carbon and hydrogen are present and the rings share a pair of carbon atoms. Specifically, naphthalene, anthracene, phenanthrene, fluorene, or the like can be given.
“Aromatic heterocycle” refers to an aromatic ring containing elements other than carbon and hydrogen. The aromatic heterocyclic ring includes both those in which an aromatic ring is substituted with a heterocyclic ring and those in which a heterocyclic ring is substituted with an aromatic ring. In addition, for the heterocyclic ring, the number of atoms (Nr) constituting the ring skeleton is preferably Nr = 5 and / or 6. Further, the type and number of atoms other than carbon atoms (heterogeneous atoms) constituting the ring skeleton are not particularly limited. For example, a sulfur atom, a nitrogen atom, an oxygen atom, a selenium atom, or a silicon atom is preferably used. Two or more types and / or two or more heteroatoms may be contained in the ring skeleton. In particular, as a heterocyclic ring having a 5-membered ring structure, thiophene, pyrrole, furan, selenophene, and silole, or a heterocyclic ring in which the 3- and 4-position carbons of the compound are replaced with nitrogen are preferably used. Pyridine is desirably used as the heterocyclic ring.

When each group selected as a structure representing Ar or X has a substituent, examples of the substituent include a hydrogen atom, an alkyl group, an alkoxyl group, an aryl group, an aralkyl group, a substituted amino group, and a halogen atom. .
The alkyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a tertiary butyl group.
As an alkoxyl group, a C1-C10 thing is desirable, for example, a methoxy group, an ethoxy group, a propoxy group, or an isopropoxy group etc. are mentioned.
As the aryl group, those having 6 to 20 carbon atoms are desirable, and examples thereof include a phenyl group and a toluyl group.
As the aralkyl group, those having 7 to 20 carbon atoms are desirable, and examples thereof include a benzyl group and a phenethyl group.
Examples of the substituent of the substituted amino group include an alkyl group, an aryl group, and an aralkyl group, and specific examples are as described above.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among them, a fluorine atom is desirable.
A substituted or unsubstituted phenyl group, a substituted or unsubstituted aromatic monovalent aromatic hydrocarbon having 2 to 10 carbon atoms, and a substituted or unsubstituted monovalent aromatic heterocyclic ring are the same as described above. .

  When the light emitting material is a low molecular light emitting material, the light emitting layer 20 is preferably configured to include a binder resin. The light emitting layer 20 may be doped (doped) with a dye compound different from the light emitting material as a guest material in the light emitting material for the purpose of improving the durability of the organic electroluminescent device or improving the light emitting efficiency. The ratio of the addition (doping) of the dye compound in the light emitting layer 20 is, for example, about 0.001 wt% to 40 wt%, desirably about 0.001 wt% to 10 wt%. As the coloring compound used for this addition (doping), an organic compound that has good compatibility with the light emitting material and does not hinder the formation of a good thin film of the light emitting layer is used, and preferably 4-dicyanmethylene-2 -Methyl-6- (p2dimethylaminostyryl) -4H-pyran (DCM) derivative, quinacridone derivative, rubrene derivative, porphyrin or the like is used. Preferable specific examples include, but are not limited to, the following compounds (III-1) to (III-5).

  Here, the light emitting layer 20 uses a coating liquid containing a light emitting material, other additives (for example, a dye compound) and a solvent for dissolving or dispersing them, and for example, this is formed by a spray method or an electrospray method. Formed by. Of course, the light emitting layer 20 may be formed by forming a film using a spin coating method, a dip method or the like. However, in the case where a low molecular light emitting material is used as the light emitting material, the coating liquid includes a binder resin.

  Next, as shown in FIG. 4G, the intermediate layer 18B is formed on the transparent insulator substrate 10 on which the light emitting layer 20 is formed. The material composing the intermediate layer 18B is a mixed material of the material composing the light emitting layer 20 (for example, light emitting material) and the material composing the electron transport layer 22 (for example, electron transporting material).

  Here, the intermediate layer 18B is formed by using a coating liquid containing a light emitting material and a hole transport material and a solvent for dissolving or dispersing them, and for example, forming the film by a spray method or an electrospray method. The

  Next, as shown in FIG. 4H, the electron transport layer 22 is formed on the transparent insulator substrate 10 on which the intermediate layer 18B is formed. Examples of the electron transport material constituting the electron transport layer 22 preferably include an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, or a fluorenylidenemethane derivative. Preferred specific examples include, but are not limited to, the following compounds (IV-1) to (IV-3).

  Here, the electron transport layer 22 is formed by using a coating liquid containing an electron transport material and a solvent for dissolving or dispersing the electron transport material, and forming the film by, for example, a spray method or an electrospray method. Of course, the electron transport layer 22 may be formed by film formation using a spin coating method, a dip method or the like.

  Next, as shown in FIG. 4I, the back electrode 24 is formed on the transparent insulator substrate 10 on which the electron transport layer 22 is formed. The back electrode 24 is made of a metal having a low work function in order to inject electrons, and particularly preferably includes magnesium, aluminum, silver, indium, or an alloy thereof. The back electrode 24 is formed by, for example, vapor deposition or sputtering.

Although not shown, a protective layer may be formed on the back electrode 24 in order to prevent further deterioration of the element due to moisture or oxygen. Specific materials for the protective layer include metals (In, Sn, Pb, Au, Cu, Ag, Al, etc.), metal oxides (MgO, SiO ₂ , TiO ₂ etc.), or resins (polyethylene resin, Polyurea resin or polyimide resin). For the formation of the protective layer, for example, a vapor deposition method, a sputtering method, a plasma polymerization method, a CVD method, or a coating method is applied.

  In the method of manufacturing the organic electroluminescent element according to the present embodiment described above, the hole transport layer 16, the intermediate layer 18A, the light emitting layer 20, the intermediate layer 18B, and the electron transport layer 22 are sprayed with a coating liquid in a mist form. It is preferable to form a film continuously by a spray method or an electrospray method.

  Specifically, for example, the hole transport layer 16 is formed by spraying the coating liquid with a nozzle 40 that sprays the coating liquid for forming the hole transport layer 16 (see FIG. 4D). At this time, the nozzle 40 and the transparent insulator substrate 10 are relatively moved to form the hole transport layer 16 in a specific region. This operation is the same for the formation of other layers.

  Next, without ending spraying of the coating liquid for forming the hole transport layer 16 by the nozzle 40, the spraying area by the nozzle 40 (area where the mist-like coating liquid contacts the coating surface) is overlapped. The intermediate layer 18A is formed by spraying the coating liquid with the nozzle 42 that sprays the coating liquid for forming the light emitting layer 20 (see FIG. 4E). That is, the intermediate layer 18 </ b> A is formed by spraying the coating liquid containing the hole transport material with the nozzle 40 and spraying the coating liquid containing the light emitting material with the nozzle 42. By adjusting the spray amount of each coating solution, the mixing ratio of both the upper layer and lower layer constituent materials constituting the intermediate layer 18A is adjusted.

  Next, the spraying of the coating liquid for forming the hole transport layer 16 by the nozzle 40 is terminated, while the spraying of the coating liquid for forming the light emitting layer 20 by the nozzle 42 is continued, whereby the light emitting layer 20. (See FIG. 4F).

  Next, without ending the spraying of the coating liquid for forming the light emitting layer 20 by the nozzle 42, the electrons are overlapped with the spraying area (the area where the mist-like coating liquid is in contact with the coating surface) by the nozzle 44. The intermediate layer 18B is formed by spraying the coating liquid with a nozzle 44 that sprays the coating liquid for forming the transport layer 22 (see FIG. 4G). That is, the intermediate layer 18 </ b> B is formed by spraying the coating liquid containing the light emitting material with the nozzle 42 and spraying the coating liquid containing the electron transport material with the nozzle 44. By adjusting the spray amount of each coating solution, the mixing ratio of both the upper layer and lower layer constituent materials constituting the intermediate layer 18B is adjusted.

  Next, spraying of the coating liquid for forming the light emitting layer 20 by the nozzle 42 is terminated, while spraying of the coating liquid for forming the electron transport layer 22 by the nozzle 44 is continued, whereby the electron transport layer 22 is continued. (See FIG. 4H).

    As described above, in the method of spraying the coating liquid for forming each layer in a mist (spray method, electrospray method, etc.), the raw material organic materials (light emitting material, charge transport material, etc.) constituting each layer are dissolved in a solvent or The dispersed coating liquid is ejected from the nozzle in the form of a mist. Here, when a volatile organic solvent is applied as the solvent, the organic solvent volatilizes in the process in which the mist-like coating liquid reaches the surface to be coated, and particles composed of the raw material organic material are formed. . That is, since the particles in which the organic solvent is volatilized, that is, the dried particles reach the surface to be coated, dissolution of the lower layer (organic compound layer including the intermediate layer) is suppressed, while the target layer ( An organic compound layer including an intermediate layer) is formed. Here, the volatility means that the boiling point is 200 ° C. or less.

  When forming the intermediate layers 18A and 18B in a spraying method (spray method, electrospray method, etc.) of the coating liquid, the spray amount of the two types of coating liquids to be sprayed is changed to You may form so that an interface may not be formed. Specifically, for example, after spraying the coating liquid for forming the lower layer to form the lower layer, the spraying of the coating liquid for forming the upper layer is started while spraying the coating liquid, and the spray amount Gradually increasing the spray amount of the coating liquid for forming the lower layer, and finally forming the intermediate layers 18A and 18B only as the spray of the coating liquid for forming the upper layer, Spraying of the coating liquid for forming the upper layer is continued to form the upper layer. Accordingly, the intermediate layers 18A and 18B have compositions in which the ratio of the coating liquid (raw material organic material) for forming the lower layer and the coating liquid (raw material organic material) for forming the upper layer is continuously inclined in the thickness direction. (Gradient composition), and the formation of a clear interface between the upper and lower layers and the intermediate layers 18A and 18B is suppressed.

  A technique (spray method, electrospray method, etc.) for spraying the coating liquid in a mist form makes it easy to obtain a desired film thickness, the apparatus configuration is simple and inexpensive, and cost reduction is realized. Moreover, in the method of spraying the coating liquid in the form of a mist, a target layer (an organic compound layer including an intermediate layer) can be formed continuously and efficiently by combining two or more nozzles.

  The method of spraying the coating liquid in the form of a mist may be adopted for forming only the intermediate layers 18A and 18B, and the other layers may be formed by a spin coating method, a dip method or the like.

  On the other hand, the film formation method for forming the intermediate layers 18A and 18B is not limited to the method (spray method or electrospray method) of spraying the coating liquid in a mist form, but a so-called mist (mist) of the coating liquid is used. You may employ | adopt the mist method which produces | generates and deposits this. In this mist method, for example, different coating liquids (in this embodiment, a coating liquid for forming the light emitting layer 20 and a coating liquid for forming a charge transporting layer (hole transporting layer 16 or electron transporting layer)) are used. ) From the mist generation source in which each coating liquid is injected into the carrier gas to form mist, and the steps to agitate and mix the mist supplied from the plurality of mist generation sources through the mist conveyance pipes The step of irradiating the surface to be coated (the substrate on which the lower layer is formed) with the agitated mist from a mist irradiation nozzle to form a mist deposition film (intermediate layers 18A and 18B), and drying the mist deposition film A process. In this mist method, it is preferable to charge the misted coating liquid when the misted coating liquid is transported from the mist generation source to the transport pipe. Further, the mist irradiation nozzle has a metal mesh filter, and a voltage is applied between the metal mesh filter and a surface to be coated (a holding member for holding an object to be coated (a substrate on which a lower layer is formed)) for irradiation. The mist may be accelerated by an applied voltage.

As a film forming apparatus applied to the mist method as described above, for example, as shown in FIG.
Different coating liquids (in this embodiment, a coating liquid for forming the light emitting layer 20 and two kinds of coating liquids for forming the charge transporting layer (the hole transporting layer 16 or the electron transporting layer)) are transported gases. Mist forming means 52A and 52B for injecting and forming a mist of each coating liquid;
Coating liquid supply means 53A, 53B (for example, comprising a pump, a flow rate control valve and a flow rate measuring device not shown) for supplying a coating liquid to the mist forming means 52A, 52B;
Carrier gas supply means 56A, 56B for transporting the mist formed by the mist forming means 52A, 52B to the mist transport pipes 54A, 54B;
A mist stirring tank 58 for stirring and mixing the mist of each coating solution supplied by the mist transport pipes 54A and 54B;
A mist irradiation nozzle 60 for irradiating the object to be coated 10A with the mist of each of the mixed coating solutions;
A heater 62 for heating the workpiece 10A;
And a holding member 64 for fixing the object to be coated 10A.
In addition, the mist stirring tank 58, the mist irradiation nozzle 60, the heater 62, and the holding member 64 are disposed in a film forming chamber 66 that includes a housing having a gas discharge port 66A.
The coating liquid supply means 53A and 53B are connected to storage containers 55A and 55B for storing the coating liquid, and the coating liquid is supplied to the mist forming means 52A and 52B as needed by the coating liquid supply means 53A and 53B. It is comprised so that.

  Here, in the mist forming means 52A and 52B, the mist of each coating liquid is formed by spraying into the carrier gas from a nozzle (not shown). As the mist forming means 52A and 52B, there are those using a spray method or those using an ultrasonic vibrator by a piezo. Preferably, those using an ultrasonic vibrator made of a piezo are used. In the mist forming means 52A and 52B, the mist formation amount is adjusted and the mist diameter is set to 0.5 μm or more and 30 μm or less, for example, depending on the viscosity of the coating liquid, the surface tension, the vibration frequency of the ultrasonic vibrator, and the like.

  Further, in the mist formation process by the mist forming means 52A and 52B, the mist may be charged simultaneously with the mist formation. As a method for charging, for example, a method is adopted in which an electrode is installed at the center of a nozzle (not shown) for generating mist of the mist forming means 52A, 52B and a voltage is applied. The formed mist of the coating solution floats in the carrier gas and is transferred to the mist stirring tank 58 through the mist transfer pipes 54A and 54B. Gases such as nitrogen, argon and helium are sent as carrier gases from the carrier gas supply means 56A and 56A to the mist forming means 52A and 52A. The carrier gas supply means 56A and 56B include, for example, a gas cylinder, a gas pressure regulator, a gas flow rate controller, and the like.

  The mist of the coating liquid formed in the mist forming means 52A and 52B is supplied to the mist stirring tank 58 through the mist transport pipes 54A and 54A by the transport gas. In the mist stirring tank 58, convection is caused by the supplied carrier gas, and mists of different coating liquids are stirred and mixed. At this time, since the mists of different coating solutions are charged to the same polarity, they repel each other and are mixed while being agglomerated by stirring. A heating source such as a heater may be installed in the mist stirring tank 58. Since a part of the solvent constituting the mist is evaporated by a heating source such as a heater and the concentration of the raw material organic material of the coating liquid is increased, a desired film thickness can be easily obtained in a relatively short time.

  The mist of the coating liquid stirred in the mist stirring tank 58 passes through the opening provided in the direction of the coating target 10A (coating surface) of the mist stirring tank 58, that is, the coating target 10A through the mist irradiation nozzle 60. Is injected into. The mist irradiation nozzle 60 is preferably composed of a metal mesh filter, and mist larger than the opening hole diameter of the metal mesh filter is collected here, so that it functions as a so-called misrefiner for reducing the particle size distribution of the mist. . Further, by applying a voltage between the mist irradiation nozzle 60 and the holding member 64 so that the holding member 64 becomes a counter charge of the charging mist, the mist of the charged coating liquid sprayed from the mist irradiation nozzle 60 is applied. Is accelerated by the electric field. Therefore, the deposition rate of the coating liquid mist on the object to be coated 10A is controlled, the coating liquid mist is accelerated to obtain a desired film thickness in a short time, and the coating liquid mist deposition rate is lowered to achieve flatness. A good film can be obtained.

  In the mist method, for example, the particle size of the mist of the coating solution is preferably 0.5 μm or more and 30 μm or less, and this increases the ratio of the surface area to the mist volume of the coating solution, which is lower than the boiling point of the solvent in the atmosphere. The solvent tends to vaporize at temperature. Therefore, by heating the object to be coated 10A with the heater 62, the solvent evaporates at the same time as the mist of the coating liquid adheres to the object to be coated 10A and dissolves in the lower layer (organic compound layer). While suppressing, the film (layer) is laminated. Further, by depositing a mist-like coating liquid (raw material organic material) on the object to be coated 10A, it is easy to obtain an arbitrary film thickness, and the configuration of the manufacturing apparatus is not more expensive than the vacuum evaporation machine, and is relatively inexpensive Is something. Further, by combining a plurality of mist generating sources, formation of mixed layers (intermediate layers 18A and 18B) in which different coating liquids are mixed continuously and efficiently is realized.

  In the mist method, when the intermediate layers 18A and 18B are formed, the deposition rates of the mists of the two coating solutions may be changed so as not to form an interface between the upper layer and the lower layer. Specifically, for example, after the mist of the coating liquid for forming the lower layer is introduced into the mist stirring tank 58 and irradiated from the mist irradiation nozzle 60 to form the lower layer, the mist of the coating liquid is continuously applied. While introducing into the mist stirring tank 58, the mist of the coating liquid for forming the upper layer is gradually introduced and mixed into the mist stirring tank 58 from a mist transport pipe different from the former, and the mist of the coating liquid is continuously mixed. Is applied to the object to be coated 10A (lower layer) to form an intermediate mixed layer. Next, the mist of the coating liquid for forming the lower layer in the mist stirring tank 58 is gradually reduced, and the mist of the coating liquid (raw material organic material) for forming the lower layer in the mist of the coating liquid to be irradiated is reduced. The ratio is decreased, and the intermediate layers 18A and 18B are formed with the composition of the irradiation mist only as the mist of the coating solution for forming the upper layer, and the upper layer is formed as it is. Accordingly, the intermediate layers 18A and 18B have compositions in which the ratio of the coating liquid (raw material organic material) for forming the lower layer and the coating liquid (raw material organic material) for forming the upper layer is continuously inclined in the thickness direction. (Gradient composition), and the formation of a clear interface between the upper and lower layers and the intermediate layers 18A and 18B is suppressed.

  In the above mist method, the case where the intermediate layers 18A and 18B are formed using two types of coating liquids has been described. Of course, the method is applied to the case where other layers are formed using one type of coating liquid. May be. Thereby, the intermediate layers 18A and 18B and other layers (the light emitting layer 20 and the charge transport layer) are continuously and efficiently formed.

  Here, in the technique of spraying the coating liquid in the form of a mist or the mist method of generating and depositing a mist of the coating liquid (mist), the solvent of the coating liquid used is a raw material organic material (light emitting material) , A charge transporting material, etc.) and a volatile organic solvent as described above. Typical examples of the organic solvent include 2-methyl-1-propanol, benzene, toluene, tetrahydrofuran and the like.

  The film thickness of each layer formed by the method of spraying the coating liquid in the form of a mist or the mist method of generating a mist (mist) of the coating liquid and depositing it is 0.5 nm or more and 1000 nm or less, for example, Desirably, it is 10 nm or more and 500 nm or less.

  The following examples illustrate the invention. In addition, this invention is not limited only by these Examples.

[Example A]
In this example, an example in which an organic electroluminescent element is manufactured using a spray method as described below will be described.

(Example A1)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulator substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the substrate surface with ultraviolet rays / ozone (UV / O ₃ ), 3,4-ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is applied by spin coating at 3000 rpm for 60 seconds to form a film. A hole injection layer having a thickness of 10 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of the following compound A [weight average molecular weight Mw = 5.0 × 10 ⁴ ] is applied by spraying onto the substrate on which the hole injection layer is formed. A 50 nm hole transport layer was formed.
Next, a 0.8 wt% monochlorobenzene solution of the following compound A and a 0.8 wt% monochlorobenzene solution of the following compound B [weight average molecular weight Mw = 6 × 10 ⁴ ] are simultaneously sprayed from different nozzles, respectively. An intermediate layer having a film thickness of 15 nm is applied on the substrate on which the hole transport layer is formed (the spray amount ratio (weight ratio) of each solution (coating solution) is the following compound A: the following compound B = 1: 1). Formed.
Next, a 50 nm light emitting layer was formed on the intermediate layer by applying a 0.8 wt% toluene solution of the following compound B by a spray method.
Next, the substrate is transferred to a vacuum evaporation apparatus, and LiF is deposited to a thickness of 5 nm. Subsequently, after forming a Ca film with a thickness of 30 nm, Al was vapor-deposited to 150 nm, and these laminates were used as back electrodes.
Finally, glass sealing was performed to obtain an organic electroluminescent element. When the cross section of each organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example A2)
On the hole transport layer made of the compound A formed in the same manner as in Example A1, a 0.8% monochlorobenzene solution of the compound A and the following compound C weight average molecular weight Mw = 7.0 × 10 ⁴ ] A 0.8 wt% monochlorobenzene solution of the above is simultaneously applied from different nozzles by a spray method (the spray amount ratio (weight ratio) of each solution (coating solution) is the above compound A: the following compound C = 1: 1) An intermediate layer having a thickness of 15 nm was formed.
Next, a 50 nm light emitting layer was formed on the intermediate layer by spray coating a 0.8 wt% monochlorobenzene solution of the following compound C.
Next, a back electrode was formed in the same manner as in Example A1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example A3)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulator substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the substrate surface with ultraviolet rays / ozone (UV / O ₃ ), 3,4-ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) was applied by spin coating at 3000 rpm for 60 seconds to form a film. A hole injection layer having a thickness of 10 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of Compound A was applied by a spray method to form a 50 nm hole transport layer.
Next, a 0.8% monochlorobenzene solution of Compound C was applied by a spray method to form a 50 nm light emitting layer.
Next, a 0.8% monochlorobenzene solution of the compound C and a 0.8 wt% monochlorobenzene solution of the following compound D are simultaneously applied from different nozzles to the substrate on which the light emitting layer is formed by spraying ( The spray amount ratio (weight ratio) of each solution (coating liquid) was the compound C: the following compound D = 1: 1, thereby forming an intermediate layer having a film thickness of 15 nm.
Next, an electron transport layer having a thickness of 10 nm was formed by applying a 0.8 wt% monochlorobenzene solution of the following compound D by a spray method.
Next, a back electrode was formed in the same manner as in Example A1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example A4)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulator substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the surface of the substrate with ultraviolet rays / ozone (UV / O ₃ ), a 1.0 wt% toluene solution of polyaniline is applied onto the substrate by a spray method to form a hole injection layer having a thickness of 5 nm. Formed.
Next, a 1.0 wt% toluene solution of polyaniline and a 0.8 wt% toluene solution of compound A were simultaneously applied from different nozzles by a spray method, and applied onto the substrate on which the hole injection layer was formed. (The spray amount ratio (weight ratio) of each solution (coating solution) was polyaniline: compound A = 0.3: 1) to form an intermediate layer having a thickness of 10 nm.
Next, a hole transport layer having a thickness of 40 nm was formed on the intermediate layer by applying a 0.8 wt% toluene solution of the compound A by a spray method.
Next, a 0.8 wt% toluene solution of the compound C was applied by a spray method to form a light emitting layer having a thickness of 50 nm.
Next, a back electrode was formed in the same manner as in Example A1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Comparative Example A1)
On the PEDOT / PSS hole injection layer formed in the same manner as in Example A1, a 0.8 wt% monochlorobenzene solution of Compound A was applied by spin coating and baked at 130 ° C. for 30 minutes in a nitrogen atmosphere. As a result, a hole transport layer was formed.
Thereafter, a 0.8 wt% monochlorobenzene solution of the compound B was applied by a spin coating method and baked at 130 ° C. for 30 minutes in a nitrogen atmosphere to form a light emitting layer.
Next, a back electrode was formed in the same manner as in Example A1, and sealed with glass to obtain an organic electroluminescent element.
When the cross section of the element was observed, it was confirmed that the hole transport layer of Compound A was dissolved by applying a monochlorobenzene solution of Compound B.

(Comparative Example A2)
In Example A1, an organic electroluminescent element was produced in the same manner as in Example 1 except that no intermediate layer was formed between the hole transport layer and the light emitting layer. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Evaluation)
The luminance half-life of the produced organic electroluminescent device was measured. Table 1 shows the relative luminance half-life when the luminance half-life of Comparative Example A1 is 1.

Note that the luminance half-life (the time from the initial luminance to the luminance halving) is set so that the initial luminance is 50 cd / m ^2, and the time until the luminance is halved from the initial value by constant current driving is the luminance. The half life (hr) was used.

  As shown in Table 1, the lifetimes of Examples A1, A2, A3, A4 and Comparative Example A2 formed by the spray method are 3 to 5 times longer than Comparative Example A1 formed by the spin coating method. became. Moreover, about Example A1, A2, A3, A4 which formed the intermediate | middle layer, the lifetime became long rather than the comparative example A2 which did not form an intermediate | middle layer.

[Example B]
In this example, an example in which an organic electroluminescent element is manufactured using a mist method as described below is shown.

(Example B1)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulating substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the substrate surface with ultraviolet rays / ozone (UV / O ₃ ), 3,4-ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is applied by spin coating at 3000 rpm for 60 seconds to form a film. A hole injection layer having a thickness of 10 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of the compound A [weight average molecular weight Mw = 5.0 × 10 ⁴ ] is made into a mist and irradiated onto the entire surface of the substrate on which the hole injection layer is formed from the mist irradiation nozzle. As a result, a hole transport layer having a thickness of 50 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of the compound A and a 0.8 wt% monochlorobenzene solution of the compound B [weight average molecular weight Mw = 6.0 × 10 ⁴ ] are respectively used as different mist generation sources. After being converted into mist, introduced into a mist stirring tank and stirred and mixed (mixing ratio (weight ratio) of each solution (coating solution): Compound A: Compound B = 1: 1), hole transport from the mist irradiation nozzle An intermediate layer having a thickness of 15 nm was formed by irradiating the entire surface of the substrate on which the layer was formed.
Next, on the intermediate layer, a 0.8 wt% monochlorobenzene solution of the compound B was misted and irradiated with mist to form a 50 nm light emitting layer.
Next, the substrate is transferred to a vacuum evaporation apparatus, and LiF is deposited to a thickness of 5 nm. Subsequently, after forming a Ca film with a thickness of 30 nm, Al was vapor-deposited to 150 nm, and these laminates were used as back electrodes.
Finally, glass sealing was performed to obtain an organic electroluminescent element. When the cross section of the organic layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example B2)
A 0.8% monochlorobenzene solution of the compound A and the compound C [weight average molecular weight Mw = 7.0 × 10 ⁴ ] on the hole transport layer of the compound A formed by the same method as in Example B1. The 0.8% monochlorobenzene solution of each was misted at different mist generation sources, introduced into a mist stirring tank, stirred and mixed (the mixing ratio (weight ratio) of each solution (coating solution) was the above compound A) : Compound C = 1: 1), an intermediate layer having a film thickness of 15 nm was formed by irradiating one surface from a mist irradiation nozzle.
Next, a 0.8% monochlorobenzene solution of Compound C was misted on the intermediate layer and irradiated to form a 50 nm light emitting layer.
Next, a back electrode was formed in the same manner as in Example B1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example B3)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulator substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the substrate surface with ultraviolet rays / ozone (UV / O ₃ ), 3,4-ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is applied by spin coating at 3000 rpm for 60 seconds to form a film. A hole injection layer having a thickness of 10 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of Compound A was made into a mist, and a hole transport layer having a thickness of 50 nm was formed by irradiating the entire surface of the substrate on which the hole injection layer was formed from a mist irradiation nozzle.
Next, a 0.8% monochlorobenzene solution of the compound C was misted and irradiated onto the substrate from a mist irradiation nozzle to form a 50 nm light emitting layer.
Next, the 0.8% monochlorobenzene solution of the compound C and the 0.8 wt% monochlorobenzene solution of the compound D are misted in different mist generation sources, introduced into a mist stirring tank, and stirred and mixed. (Spraying amount ratio (weight ratio) of each solution (coating solution): Compound C: Compound D = 1: 1), and then irradiating the entire surface of the substrate on which the light emitting layer is formed from the mist irradiation nozzle. An intermediate layer having a thickness of 15 nm was formed.
Next, a 0.8 wt% monochlorobenzene solution of the compound D was misted and irradiated onto the substrate from a mist irradiation nozzle to form an electron transport layer having a thickness of 10 nm.
Next, a back electrode was formed in the same manner as in Example B1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Example A4)
A substrate on which a ITO electrode (transparent electrode) was patterned in a strip shape having a width of 2 mm was prepared on a glass substrate (transparent insulator substrate), and this was washed with a neutral detergent, acetone, and isopropyl alcohol.
Next, after cleaning the surface of the substrate with ultraviolet rays / ozone (UV / O ₃ ), a 1.0 wt% toluene solution of polyaniline is misted and irradiated onto the substrate to form a hole injection layer having a thickness of 5 nm. did.
Next, a 1.0 wt% toluene solution of polyaniline and a 0.8 wt% toluene solution of compound A are misted in different mist generation sources, introduced into a mist stirring tank, and stirred and mixed ( The spray amount ratio (weight ratio) of each solution (coating solution) is polyaniline: compound A = 0.3: 1), and the film is formed by irradiating the entire surface of the substrate on which the hole injection layer is formed from the mist irradiation nozzle. An intermediate layer having a thickness of 10 nm was formed.
Next, a hole transport layer having a thickness of 40 nm was formed on the intermediate layer by applying a 0.8 wt% toluene solution of the compound A by a spray method.
Next, a 0.8 wt% toluene solution of the compound C was misted and irradiated onto the substrate from a mist irradiation nozzle to form a 50 nm light emitting layer.
Next, a back electrode was formed in the same manner as in Example A1, and sealed with glass to obtain an organic electroluminescent element. When the cross section of the organic compound layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Comparative Example B1)
On the PEDOT / PSS hole injection layer formed in the same manner as in Example B1, a 0.8 wt% monochlorobenzene solution of Compound A was applied by spin coating, and baked at 130 ° C. for 30 minutes in a nitrogen atmosphere. As a result, a hole transport layer was formed.
Thereafter, a 0.8 wt% monochlorobenzene solution of the compound B was applied by a spin coating method and baked at 130 ° C. for 30 minutes in a nitrogen atmosphere to form a light emitting layer.
Next, a back electrode was formed in the same manner as in Example B1, and sealed with glass to obtain an organic electroluminescent element.
When the cross section of the element was observed, it was confirmed that the hole transport layer of Compound A was dissolved by applying a monochlorobenzene solution of Compound B.

(Comparative Example B2)
In Example B1, an organic electroluminescent element was produced in the same manner as in Example B1, except that no intermediate layer was formed between the hole transport layer and the light emitting layer. When the cross section of the organic layer of the obtained organic electroluminescent element was observed, each interface was clearly confirmed.

(Evaluation)
The luminance half-life of the produced organic electroluminescent device was measured. Table 2 shows the relative luminance half-life when the luminance half-life of Comparative Example B1 is 1.

  As shown in Table 2, the lifetimes of Examples B1, 2, 3, 4 and Comparative Example B2 formed with mist were 3 to 5 times longer than those of Comparative Example B1 formed by spin coating. . Moreover, about Example B1, 2, 3, 4 which formed the intermediate | middle layer, the lifetime became longer than comparative example B2 which did not form an intermediate | middle layer.

It is a schematic block diagram which shows the organic electroluminescent element which concerns on embodiment. It is a schematic block diagram which shows the organic electroluminescent element which concerns on other embodiment. It is a schematic block diagram which shows the organic electroluminescent element which concerns on other embodiment. It is process drawing which shows the manufacturing method of the organic electroluminescent element which concerns on embodiment. It is a schematic block diagram which shows the film-forming apparatus applied to a mist method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transparent insulator board | substrate 10A To-be-coated object 12 Transparent electrode 14 Hole injection layer 16 Hole transport layer 18A, 18B Intermediate | middle layer 20 Light emitting layer 22 Electron transport layer 24 Back electrode 30 Voltage application apparatus 40, 42, 44 Nozzle 52A, 52B Mist forming means 53A, 53B Coating liquid supply means 54A, 54B Mist transport pipes 55A, 55B Storage containers 56A, 56B Transport gas supply means 58 Mist stirring tank 60 Mist irradiation nozzle 62 Heater 64 Holding member 66 Film forming chamber 66A Gas outlet 100 Organic electroluminescent device

Claims (3)

A pair of electrodes consisting of an anode and a cathode, at least one of which is transparent or translucent,
A first organic compound layer disposed between the pair of electrodes;
A second organic compound layer disposed between the pair of electrodes;
It is disposed between the first organic compound layer and the second organic compound layer, and includes a material constituting the first organic compound layer and a material constituting the second organic compound layer. The middle layer,
An organic electroluminescent device comprising: The first organic compound layer is a light emitting layer;
The second organic compound layer is a charge transport layer;
The intermediate layer is an intermediate layer configured to include a material constituting the light emitting layer and a material constituting the charge transport layer,
The organic electroluminescent element according to claim 1. The organic electroluminescence device according to claim 1 or 2, arranged in at least one of a matrix shape and a segment shape,
Driving means for driving the organic electroluminescent element;
A display device comprising:

Images