JP2019145631A - Organic electroluminescent element, method for producing the same, and composition for intermediate layer - Google Patents

Abstract

To provide an organic EL element capable of suppressing dissolution and penetration into a light emitting layer and a lower layer of the light emitting layer when forming an organic EL layer by a coating method.SOLUTION: The organic EL element includes: a first electrode layer 2; a hole injection transport layer 3; a light emitting layer 4; an electron injection transport layer 6; and a second electrode layer 7, laminated in this order. Between the hole injection transport layer and the light emitting layer, or between the electron injection transport layer and the light emitting layer, an intermediate layer 5 is included. The intermediate layer contains an organic material.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present disclosure relate to an organic electroluminescent device having an intermediate layer.

  The organic electroluminescence element has high visibility due to self-coloring, is an all-solid-state display unlike a liquid crystal display device, has excellent impact resistance, has a fast response speed, is less affected by temperature changes, and It attracts attention because of its advantages such as a wide viewing angle. Hereinafter, organic electroluminescence may be abbreviated as organic EL.

  The organic EL element usually has a configuration in which an organic EL layer composed of a plurality of functional layers including a base material, a first electrode layer, and a light emitting layer, and a second electrode layer are laminated in this order. Here, there are roughly two methods for forming the organic EL layer. Specific examples include a dry process method in which a film is formed by vapor deposition under vacuum and a coating method in which a film is formed by applying a composition for an organic EL layer. Among them, the coating method is attracting attention because it is excellent in terms of increasing the area of the organic EL element and increasing the productivity.

JP 2013-225678 A

  When an organic EL layer is formed by a coating method, particularly when a charge injection / transport layer such as a hole injection / transport layer or an electron injection / transport layer is formed on a light-emitting layer constituting the organic EL layer by a coating method, the charge injection / transport is performed. There is a problem that the solvent contained in the composition for forming the layer dissolves and penetrates into the light emitting layer and the lower layer of the light emitting layer and deteriorates. Therefore, for example, as shown in FIG. 2A, the substrate 1, the first electrode layer 2, the hole injection transport layer 3 (here, the hole injection layer 3a and the hole transport layer 3b), and the light emitting layer 4 When the electron injecting and transporting layer 6 (here, the electron transporting layer 6b) is formed on the light emitting layer 4 using a coating method as shown in FIG. In the solvent used in the composition constituting 6b, the electron transport layer 6b is a material that dissolves and is difficult to dissolve and penetrate into the light emitting layer 4 and the hole injection transport layer 3 that are the lower layers of the electron transport layer 6b. Is required. However, selection of a material having such characteristics is not easy, and the degree of freedom in material selection is significantly reduced.

  For example, Patent Document 1 describes that the lower layer is resinized and the solvent solubility is deteriorated so that the lower layer does not dissolve in the upper layer coating solution. On the other hand, the technique described in Patent Document 1 is not a technique of forming a charge injecting and transporting layer on a light emitting layer using a coating method. A technique for forming the charge injecting and transporting layer on the light emitting layer using a coating method is not particularly known.

  The present disclosure has been made in view of the above-described problems. When a charge injection transport layer such as a hole injection transport layer or an electron injection transport layer is formed on a light emitting layer using a coating method, the charge injection transport layer is formed. It is a main object to provide an organic EL device capable of suppressing the solvent contained in the composition for charge injecting and transporting layer constituting the solvent from being dissolved and permeated into the light emitting layer and the lower layer of the light emitting layer.

  The present disclosure is an organic EL element in which a first electrode layer, a hole injecting and transporting layer, a light emitting layer, an electron injecting and transporting layer, and a second electrode layer are laminated in this order. Provided is an organic EL device having an intermediate layer between a light emitting layer or between the electron injecting and transporting layer and the light emitting layer, wherein the intermediate layer contains an organic material.

  The present disclosure is an organic EL element manufacturing method for manufacturing an organic EL element in which a first electrode layer, a hole injection transport layer, a light emitting layer, an electron injection transport layer, and a second electrode layer are laminated in this order. A light emitting layer forming step of forming the light emitting layer, an intermediate layer forming step of forming an intermediate layer on one surface of the light emitting layer, and the hole on the surface of the intermediate layer opposite to the light emitting layer. A hole injecting and transporting layer forming step or an electron injecting and transporting layer forming step for forming the injecting and transporting layer or the electron injecting and transporting layer, wherein the intermediate layer forming step comprises: The intermediate layer is formed by coating, and the intermediate layer composition contains an organic material and a solvent. The solvent dissolves the organic material and does not dissolve the light emitting material contained in the light emitting layer. The manufacturing method of an organic EL element is provided.

  The present disclosure is an organic EL element manufacturing method for manufacturing an organic EL element in which a first electrode layer, a hole injection transport layer, a light emitting layer, an electron injection transport layer, and a second electrode layer are laminated in this order. A light emitting layer forming step of forming the light emitting layer, an intermediate layer forming step of forming an intermediate layer on one surface of the light emitting layer, and the hole on the surface of the intermediate layer opposite to the light emitting layer. A hole injecting and transporting layer forming step or an electron injecting and transporting layer forming step for forming the injecting and transporting layer or the electron injecting and transporting layer, and the intermediate layer forming step includes a composition for an intermediate layer constituting the intermediate layer. It is a step of coating to form the intermediate layer, and the intermediate layer composition contains an organic material and does not contain a solvent.

  The present disclosure is a composition constituting an intermediate layer formed between a light emitting layer constituting an organic EL element and a hole injecting and transporting layer or an electron injecting and transporting layer, and the composition contains an organic material and a solvent. And the composition for intermediate | middle layers whose said organic material is C12-C50 hydrocarbon is provided.

  The present disclosure is a composition constituting an intermediate layer formed between a light emitting layer constituting an organic EL element and a hole injecting and transporting layer or an electron injecting and transporting layer, and the composition contains an organic material, And the composition for intermediate | middle layers which does not contain a solvent and whose said organic material is a C12-C50 hydrocarbon is provided.

  The present disclosure is included in a composition for a charge injection / transport layer that forms a charge injection / transport layer when a charge injection / transport layer such as a hole injection / transport layer or an electron injection / transport layer is formed on a light emitting layer using a coating method. The organic EL element which can suppress that the solvent to be dissolved melt | dissolves and osmose | permeates the light emitting layer and the lower layer of the said light emitting layer can be provided.

It is a schematic sectional drawing which shows an example of the organic EL element of this indication. It is a schematic sectional drawing which shows an example of the conventional organic EL element.

  In this specification, when a certain configuration such as a certain member or a certain region is “above (or below)” another configuration such as another member or another region, unless otherwise limited, This includes not only when directly above (or directly below) another configuration, but also when above (or below) another configuration, i.e., another configuration above (or below) another configuration. This includes cases where elements are included.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different modes, and should not be construed as being limited to the description of the embodiments described below. Further, in order to clarify the description, the drawings may be schematically represented with respect to the width, thickness, shape, etc. of each part as compared with the embodiment, but are merely examples, and the interpretation of the present disclosure may be interpreted. It is not limited. In addition, in the present specification and each drawing, elements similar to those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description may be omitted as appropriate. Further, for convenience of explanation, the description may be made using the terms “upper” or “lower”, but the vertical direction may be reversed.

  Hereinafter, the organic EL element of the present disclosure, the method for producing the organic EL element, and the intermediate layer composition will be described.

A. Organic EL Element The organic EL element of the present disclosure includes a first electrode layer, a hole injecting and transporting layer, a light emitting layer, an electron injecting and transporting layer, and a second electrode layer laminated in this order, An intermediate layer is provided between the light emitting layer or between the electron injecting and transporting layer and the light emitting layer, and the intermediate layer contains an organic material.

The organic EL element of the present disclosure will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view illustrating an example of the organic EL element of the present disclosure. As illustrated in FIG. 1, the organic EL element 100 includes a base material 1, a first electrode layer 2, a hole injection transport layer 3 (here, a hole injection layer 3 a and a hole transport layer 3 b), and a light emitting layer 4. The intermediate layer 5, the electron injection / transport layer 6 (here, the electron injection layer 6a and the electron transport layer 6b), and the second electrode layer 7 are provided in this order, and the intermediate layer 5 contains an organic material.

  The present disclosure relates to a composition for a charge injection / transport layer constituting a charge injection / transport layer when a charge injection / transport layer such as a hole injection / transport layer or an electron injection / transport layer is formed on a light emitting layer using a coating method. There is an effect that it is possible to provide an organic EL element capable of suppressing dissolution and penetration of the solvent contained in the light emitting layer and the lower layer of the light emitting layer. Specifically, the above effect can be achieved by providing an intermediate layer between the light emitting layer and the hole injecting and transporting layer or between the light emitting layer and the electron injecting and transporting layer. Further, by using a predetermined organic material as the material included in the intermediate layer, the hole injection / transport layer can be used together with the above-described effects even when the organic material is mixed in the hole injection / transport layer or the electron injection / transport layer. Alternatively, it is possible to suppress a significant decrease in the performance of the electron injecting and transporting layer. Hereinafter, the hole injection / transport layer and the electron injection / transport layer may be referred to as a charge injection / transport layer.

  Hereinafter, the organic EL element of the present disclosure will be described for each configuration.

1. Intermediate Layer The intermediate layer in the present disclosure is configured to be disposed between the hole injecting and transporting layer and the light emitting layer or between the electron injecting and transporting layer and the light emitting layer, and to contain an organic material. In the present disclosure, when the hole injection transport layer or the electron injection transport layer is formed on the light emitting layer by a coating method by having an intermediate layer, the hole injection transport layer constituting the hole injection transport layer is formed. It can suppress that the solvent contained in the composition or the composition for electron injection transport layers which comprises an electron injection transport layer melt | dissolves and osmose | permeates a light emitting layer.

  Hereinafter, the material and physical properties of the intermediate layer will be described.

(1) Material The intermediate layer contains an organic material. The organic material is preferably a material capable of exhibiting the above-described effects due to the organic EL element having the intermediate layer, and can be appropriately selected according to the types of the light emitting layer and the charge injection / transport layer. it can. The intermediate layer may contain one type of organic material or may contain a plurality of types of organic materials. Content of the organic material contained in an intermediate | middle layer can be suitably adjusted according to the kind of organic material. The content of the organic material in the solid content of the intermediate layer is, for example, 1% by mass or more, 10% by mass or more, or 30% by mass or more. On the other hand, the content of the organic material in the solid content of the intermediate layer is, for example, 99% by mass or less, 90% by mass or less, or 70% by mass or less.

  The organic material may be a hydrocarbon. This is because, when the intermediate layer is formed on the light emitting layer using a coating method, a solvent that does not dissolve the light emitting layer can be used for the intermediate layer composition that constitutes the intermediate layer. The hydrocarbon here is an organic compound containing carbon and hydrogen and having a hydrocarbon skeleton. The content of carbon atoms and hydrogen atoms in the hydrocarbon molecule is, for example, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. Also good. The hydrocarbon molecule may be composed of only carbon atoms and hydrogen atoms, and the content of carbon atoms and hydrogen atoms in the hydrocarbon molecule may be 100% by mass.

  The hydrocarbon has, for example, 12 or more carbon atoms, 20 or more carbon atoms, or 25 or more carbon atoms. When the carbon number has the above lower limit, the following effects are obtained. That is, when the charge injection / transport layer is formed on the intermediate layer using a coating method, the dissolution of the intermediate layer by the solvent contained in the charge injection / transport layer composition constituting the charge injection / transport layer is suppressed. There is an effect that can be. On the other hand, the hydrocarbon has, for example, 50 or less carbon atoms, 45 or less carbon atoms, or 40 or less carbon atoms. By having the upper limit for the number of carbon atoms, the following effects can be obtained. That is, when the charge injecting and transporting layer is formed on the intermediate layer by using a coating method, there is an effect that the charge injecting and transporting layer composition constituting the charge injecting and transporting layer is hardly repelled by the surface of the intermediate layer.

  The hydrocarbon includes, for example, a chain hydrocarbon and a cyclic hydrocarbon depending on the bonding state of carbon. In the present disclosure, the hydrocarbon is preferably a chain hydrocarbon, and among them, a chain saturated hydrocarbon is particularly preferable. It is preferable that The chain hydrocarbon may be a straight chain hydrocarbon or a branched chain hydrocarbon. When the chain hydrocarbon is a branched chain hydrocarbon, for example, it preferably has a straight chain portion having 12 to 50 carbon atoms. Further, the hydrocarbon may be a saturated hydrocarbon or an unsaturated hydrocarbon, but is preferably a saturated hydrocarbon. Therefore, according to the present disclosure, the hydrocarbon is preferably a chain saturated hydrocarbon. When the hydrocarbon is a chain saturated hydrocarbon, the band gap of the intermediate layer can be wider than the band gap of the light emitting layer or the charge injection transport layer. Thereby, the performance fall of the organic EL element by an electric charge being trapped can be suppressed. Further, when the hydrocarbon is a chain saturated hydrocarbon, the viscosity of the intermediate layer is increased. Therefore, when the charge injecting and transporting layer is laminated by a coating method so that the light emitting layer, the intermediate layer and the charge injecting and transporting layer are in this order, the charge injecting and transporting layer composition constituting the charge injecting and transporting layer It becomes difficult to penetrate into the light emitting layer. Thereby, the performance fall of the organic EL element by the composition for electric charge injection transport layers mixing in a light emitting layer can be suppressed.

  The hydrocarbon may contain a functional group. Examples of functional groups include ester bonds, amide bonds, carboxyl groups, acid anhydrides, nitrile groups, carbonyl groups, hydroxy groups, amino groups, imino groups, ether bonds, nitro groups, halogen groups, alkyl groups, thiol groups, Examples include various polar groups such as a selenol group, a ketone group, and an aldehyde group. The functional group may be a double bond (alkene) or a triple bond (alkyne). The functional group contained in the hydrocarbon is preferably an alkyl group. This is because a decrease in performance of the organic EL element due to trapping of charges can be suppressed. The hydrocarbon may contain one type of functional group in one molecule, and may contain multiple types of functional groups in one molecule. The number of functional groups contained in the hydrocarbon can be appropriately changed as necessary. Specifically, the number of hydrocarbons and functional groups contained in one molecule is, for example, 1 or more, and may be 2 or more. On the other hand, the number of functional groups contained in the hydrocarbon and one molecule is, for example, 10 or less, and may be 8 or less.

  Specific examples of the hydrocarbon include, for example, dodecane, tridecane, undecane, tetradecane, hexadecane, heptadecane, octadecane, nonadecane, icosane, henicosan, docosan, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane, hen Triacontane, Dotriacontane, Tritriacontane, Tetratriacontane, Pentatriacontane, Hexatriacontane, Heptatriacontane, Octatriacontane, Nonatriacontane, Tetracontane, Hentetracontane, Dotetracontane, Tritetracontane, Tetratetracontane, pentatetracontane, hexatetracontane, heptatetracontane, octatetracontane, nonatetracon Emissions, include straight chain paraffin such as pentacontanoic. Other examples include olefins such as 1-dodecene, 1-tridecene, 1-undecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and the like. Other examples include isoparaffins such as 7-methyltridecane, 7-n-hexyltridecane, 9-n-hexylheptadecane, 11-n-decyldocosane, 13-n-dodecylhexacosane.

  The organic material may be a hydrocarbon oil. Here, the hydrocarbon oil in the present disclosure refers to a particularly viscous material among the above-described hydrocarbons. Specifically, a hydrocarbon having 20 to 50 carbon atoms can be defined as a hydrocarbon oil. The carbon number of the hydrocarbon oil may be 25 or more, 30 or more, or 35 or more, among others.

  Examples of the hydrocarbon oil include icosane, henicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosan, triacontan, hentria contane, dotria contane, tritria contane, tetratria contane, pentatria contane. , Hexatriacontane, heptatriacontane, octatriacontane, nonatriacontane, tetracontane, hentetracontane, dotetracontane, tritetracontane, tetratetracontane, pentatetracontane, hexatetracontane, heptatetracontane, octatetra Examples thereof include straight-chain paraffins such as Kontan, Nonatetrakontan and Pentacontane. In addition, for example, isoparaffins such as 11-n-decyl docosane and 13-n-dodecyl hexacosane can be used. Other examples include liquid paraffin, hydrogenated polyisobutene, hydrogenated polydecene, squalane, squalene, light liquid isoparaffin, heavy liquid isoparaffin, liquid isoparaffin, and α-olefin oligomer.

  The intermediate layer composition constituting the intermediate layer may contain a solvent in addition to the organic material, or may not contain a solvent. When the viscosity of the organic material is high, the former is preferable. On the other hand, in the latter case, it is possible to suppress the occurrence of problems such as penetration of the solvent in the intermediate layer composition into the light emitting layer.

  When the intermediate layer composition contains an organic material and a solvent, the organic material is preferably a material that is soluble in a solvent that does not dissolve the light emitting material contained in the light emitting layer. When the organic material is such a material, when the intermediate layer is formed on the light emitting layer by using the coating method, the organic material is dissolved in the solvent contained in the intermediate layer composition constituting the intermediate layer. Can do. On the other hand, it can suppress that the light emitting material which a light emitting layer contains with the solvent contained in the said composition for intermediate | middle layers melt | dissolves.

  Here, the solvent used for the composition for the intermediate layer constituting the intermediate layer is “does not dissolve the light emitting material contained in the light emitting layer” means that the light emitting layer is not dissolved in the solvent when the solvent contacts the light emitting layer. That means. In other words, the remaining film ratio of the light emitting layer is, for example, 70% or more with respect to the solvent contained in the intermediate layer composition. The remaining film ratio of the light emitting layer is preferably 80% or more, and more preferably 90% or more. When the remaining layer ratio of the light emitting layer is within the above range with respect to the solvent contained in the intermediate layer composition, when the intermediate layer is formed on the light emitting layer using a coating method, the intermediate layer composition It can suppress that a light emitting layer is melt | dissolved by the solvent contained.

In addition, the remaining film rate of the light emitting layer mentioned above can be measured as follows. That is, first, a quartz substrate of 25 mm × 25 mm is prepared. Next, a light emitting layer is formed on the quartz substrate. Next, when measuring the remaining film ratio of the light emitting layer, spin the target solvent, that is, the solvent contained in the composition for the intermediate layer constituting the intermediate layer, on the light emitting layer with 1 mL for 25 mm × 25 mm. Apply using coater method. The number of rotations at this time can be appropriately adjusted according to the film thickness of the intermediate layer disposed so as to be in contact with the light emitting layer. Then, the solvent apply | coated on the light emitting layer is dried on the same conditions as drying the composition for intermediate | middle layers. In this way, a light emitting layer coated with a solvent is prepared.
Here, the remaining film ratio of the light-emitting layer can be measured from the ratio of the absorbance (Abs) of the absorption maximum (λmax) of the light-emitting layer in the ultraviolet-visible absorption spectrum using an ultraviolet-visible spectrophotometer. Specifically, it can be calculated by the following formula.
([Absorbance of absorption maximum of light emitting layer after solvent application] / [absorbance of absorption maximum of light emitting layer before solvent application]) × 100 (%) = remaining film ratio (%)
Also, if the light emitting layer does not have absorption in the ultraviolet visible absorption spectrum, using an atomic force microscope (AFM) or a stylus type surface shape measuring instrument (for example, DEKTAK series, manufactured by SLOANA), The residual film ratio can be determined by directly measuring the film thickness of the light emitting layer before and after the solvent application.

  The “solvent that does not dissolve the light emitting material contained in the light emitting layer” is a solvent that does not dissolve the light emitting material or the organic material but has a property of dissolving the organic material, that is, used when forming the intermediate layer by a coating method. Is a solvent contained in the intermediate layer composition. In addition, since the solvent contained in the composition for intermediate | middle layers is described in the term of the "B. manufacturing method of an organic EL element" mentioned later, description here is abbreviate | omitted.

  Furthermore, “the organic material is soluble in a solvent that does not dissolve the light-emitting material contained in the light-emitting layer” means that the organic material is soluble in the solvent contained in the intermediate layer composition. Therefore, it is preferable to select a solvent that dissolves the organic material and does not dissolve the light emitting material as the solvent contained in the intermediate layer composition. When forming an intermediate | middle layer using the apply | coating method, it can suppress that a light emitting layer is melt | dissolved by the solvent contained in the composition for intermediate | middle layers.

  The organic material preferably has a predetermined molecular weight. The mass average molecular weight of the organic material is, for example, 300 or more, preferably 500 or more, and particularly preferably 700 or more. When the mass average molecular weight of the organic material has the above lower limit, it is included in the charge injection transport layer composition constituting the charge injection transport layer when the charge injection transport layer is formed on the intermediate layer using a coating method. Generation | occurrence | production of the malfunction that an organic material melt | dissolves in a solvent can be suppressed, and it becomes possible to fully exhibit the function as an intermediate | middle layer. On the other hand, the mass average molecular weight of the organic material is, for example, 500,000 or less, preferably 400,000 or less, and particularly preferably 300,000 or less. When the charge average transport molecular weight of the organic material has the above upper limit, the charge injection transport layer composition constituting the charge injection transport layer is formed on the intermediate layer when the charge injection transport layer is formed on the intermediate layer using a coating method. It becomes easy to apply to the surface.

  The organic material is preferably electrically inactive. This is because, in the interface region between the intermediate layer and the charge injecting and transporting layer, even when an organic material is mixed in the charge injecting and transporting layer, a significant decrease in the performance of the charge injecting and transporting layer can be suppressed. Here, being electrically inactive means, for example, that the intermediate layer has a predetermined insulating property. The predetermined insulating property of the intermediate layer is described in the section “(2) Physical properties” to be described later, and thus description thereof is omitted here.

(2) Physical property The intermediate | middle layer may have insulation of the grade which an organic EL element functions. The intermediate layer preferably has a band gap larger than that of the light emitting layer or the charge injection / transport layer, for example. Specifically, it has a band gap of 3.0 eV or more, may have a band gap of 3.25 eV or more, and may have a band gap of 3.5 eV or more. On the other hand, the intermediate layer has, for example, a band gap of 5.0 eV or less, may have a band gap of 4.75 eV or less, and may have a band gap of 4.5 eV or less.

  The HOMO energy level of the intermediate layer is preferably larger than the HOMO energy level of the light emitting layer or the charge injection / transport layer with respect to the vacuum level. The specific HOMO energy level of the intermediate layer is, for example, 5.0 eV or more, and may be 5.25 eV or more. On the other hand, the HOMO energy level of the intermediate layer is, for example, 6.5 eV or less, and may be 6.25 eV or less.

  The LUMO energy level of the intermediate layer is, for example, 1.5 eV or more with respect to the vacuum level, and may be 1.75 eV or more. On the other hand, the LUMO energy level of the intermediate layer is preferably smaller than the LUMO energy level of the light emitting layer or the charge injection transport layer. The LUMO energy level of the intermediate layer is, for example, 2.5 eV or less, and may be 2.25 eV or less with respect to the vacuum level.

  The surface of the intermediate layer is coated with the composition for hole injection / transport layer constituting the hole injection / transport layer or the electron injection / transport layer constituting the electron injection / transport layer. A transport layer is formed. In the present disclosure, it is preferable that the surface of the intermediate layer has a predetermined wettability with respect to the composition for hole injection transport layer or the composition for electron injection transport layer. For example, the contact angle when the composition for hole injection / transport layer or the composition for electron injection / transport layer is applied to the surface of the intermediate layer is, for example, 1 ° or more, and preferably 5 ° or more. On the other hand, the contact angle is, for example, 50 ° or less, and preferably 30 ° or less. The hole injection / transport layer composition or the electron injection / transport layer composition can be easily applied to the surface of the intermediate layer, and the hole injection / transport layer or the electron injection / transport layer can be easily formed.

  The thickness of the intermediate layer can be appropriately adjusted according to the type of organic material contained in the intermediate layer. The thickness of the intermediate layer is, for example, 0.5 nm or more, 1 nm or more, or 10 nm or more. On the other hand, the thickness of the intermediate layer is, for example, 200 nm or less, 100 nm or less, or 50 nm or less.

2. Light emitting layer The light emitting layer in this indication is a member located in the lower layer of an intermediate layer. The light emitting layer contains a light emitting material. Furthermore, the light emitting layer may be a coating type light emitting layer formed by a coating method. In addition, it can confirm that it is a coating type light emitting layer with the kind of light emitting material contained in a light emitting layer, for example. The light emitting material used for the coating type light emitting layer is a material that dissolves in a solvent. As such a light emitting material, for example, a high molecular material or a low molecular material can be used. Here, the polymer material refers to, for example, a material having a molecular weight of 3000 to 500,000, and the low molecular material refers to, for example, a material having a molecular weight of less than 3000.

  Examples of the light emitting material include light emitting materials such as pigment materials, metal complex materials, and polymer materials.

  Examples of dye-based materials include cyclopentadiene derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds, pyridine Examples thereof include ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

  Examples of the metal complex-based material include aluminum quinolinol complex, benzoquinolinol beryllium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, and eurobium complex. Or a metal complex having a rare earth metal such as Tb, Eu, or Dy and having a oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, or the like as a ligand.

  Furthermore, examples of the polymer material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyvinylcarbazole, polyfluorene derivatives, polyquinoxaline derivatives, and copolymers thereof. Is mentioned.

  The light emitting layer may contain a doping agent for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of the doping agent include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, quinoxaline derivatives, carbazole derivatives, fluorene derivatives, and the like. It is done.

  The thickness of the light emitting layer is not particularly limited as long as it can provide a function of emitting light by providing a recombination field between electrons and holes, and can be, for example, 1 nm or more. Moreover, it can be 500 nm or less.

  The light emitting layer may be formed in a pattern so as to have light emitting portions of a plurality of colors such as red, green, and blue. Thereby, an organic EL element capable of color display can be obtained.

3. Hole injection transport layer In the present disclosure, the hole injection transport layer may be a hole injection layer having a hole injection function, may be a hole transport layer having a hole transport function, It may have both an injection function and a hole transport function. The hole injection / transport layer may be a layer in which a hole injection layer and a hole transport layer are stacked. Further, the hole injection transport layer may be a coating type hole injection transport layer formed by a coating method. In addition, it can confirm that it is a coating type positive hole injection transport layer with the kind of positive hole injection transport material contained in a positive hole injection transport layer, for example. The hole injecting and transporting material used for the coating type hole injecting and transporting layer is a material that dissolves in a solvent. In addition, as such a hole injecting and transporting material, for example, a polymer material or a low molecular material can be used, but a polymer material is usually used. Here, the polymer material refers to, for example, a material having a molecular weight of 3000 to 500,000, and the low molecular material refers to, for example, a material having a molecular weight of less than 3000.

  As the hole injecting and transporting material used for the hole injecting and transporting layer, a known material can be used. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, polythiophene derivatives, polyaniline derivatives, polypyrrole derivatives, phenylamine derivatives, anthracene derivatives, carbazole derivatives, fluorene derivatives, distyrylbenzene derivatives, polyphenylene vinylene derivatives, porphyrin derivatives, and styrylamine derivatives. Moreover, a spiro compound, a phthalocyanine compound, a metal oxide, etc. can be illustrated.

  The thickness of the hole injecting and transporting layer is not particularly limited as long as the hole injecting function and the hole transporting function are sufficiently exhibited. For example, the hole injecting and transporting layer can be 0.5 nm or more and can be 10 nm or more. preferable. The thickness of the hole injecting and transporting layer can be 500 nm or less, and preferably 200 nm or less.

4). Electron injection transport layer In the present disclosure, the electron transport layer may be an electron injection layer having an electron injection function or an electron transport layer having an electron transport function, and both an electron injection function and an electron transport function may be used. It may have a function. The electron injection / transport layer may be a layer in which an electron injection layer and an electron transport layer are stacked. Further, the electron injecting and transporting layer may be a coating type electron injecting and transporting layer formed by a coating method. In addition, it can confirm that it is a coating type electron injection transport layer with the kind of electron injection transport material contained in an electron injection transport layer, for example. The electron injecting and transporting material used for the coating type electron injecting and transporting layer is a material that dissolves in a solvent. In addition, as such an electron injecting and transporting material, for example, a polymer material or a low molecular material can be used, but a polymer material is usually used. Here, the polymer material refers to, for example, a material having a molecular weight of 3000 to 500,000, and the low molecular material refers to, for example, a material having a molecular weight of less than 3000.

  As the electron injecting and transporting material used for the electron injecting and transporting layer, a known material can be used. For example, alkali metals, alkali metal alloys, alkali metal halides, alkaline earth metals, alkaline earth metal halides, alkaline earth metal oxides, alkali metal organic complexes, magnesium halides, An oxide, aluminum oxide, etc. are mentioned. Examples of the electron injecting / transporting material include bathocuproin, bathophenanthroline, phenanthroline derivative, triazole derivative, oxadiazole derivative, pyridine derivative, nitro-substituted fluorene derivative, anthraquinodimethane derivative, diphenylquinone derivative, thiopyran dioxide Derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane derivatives, anthrone derivatives, quinoxaline derivatives, quinolinol complexes and other metal complexes, phthalocyanine compounds, distyrylpyrazine derivatives, etc. Can be mentioned.

  Further, a metal doped layer in which an alkali metal or alkaline earth metal is doped on an electron transporting organic material may be formed, and this may be used as an electron injecting and transporting layer. Examples of the electron-transporting organic material include bathocuproin, bathophenanthroline, and phenanthroline derivatives, and examples of the metal to be doped include Li, Cs, Ba, and Sr.

  The thickness of the electron injecting and transporting layer is not particularly limited as long as the electron injecting function and the electron transporting function are sufficiently exhibited.

5. 1st electrode layer The 1st electrode layer in this indication is a member arrange | positioned at the surface side opposite to the light emitting layer of a positive hole injection transport layer. The organic EL element of the present disclosure may extract light from the first electrode layer side or may extract light from the second electrode layer side. When the organic EL element extracts light from the first electrode layer side, the first electrode layer preferably has a predetermined transparency.

  In the case where the first electrode layer has a predetermined transparency, the transparency of the first electrode layer is preferably such that the light can be transmitted through the organic EL layer and displayed. For example, the transmittance in the visible light region is preferably 80% or more, and more preferably 90% or more.

  The first electrode layer is usually an anode. As a material of the first electrode layer, a material used for a general organic EL element can be used. As the anode, for example, it is preferable that the resistance is small, and a metal material that is a conductive material is generally used, but an organic compound or an inorganic compound may be used. For the anode, a conductive material having a large work function is preferably used so that holes can be easily injected. For example, metals such as Au, Cr, and Mo; indium tin oxide called ITO, indium oxide such as indium zinc oxide, zinc oxide, and indium oxide called IZO; high conductivity such as metal-doped polythiophene Molecule and the like. These conductive materials may be used alone or in combination of two or more. When two or more types are used, layers made of each material may be stacked.

  The thickness of the first electrode layer can be adjusted as appropriate according to the application of the organic EL element and the like, and is not particularly limited.

6). Second Electrode Layer The second electrode layer in the present disclosure is a member disposed on the surface side opposite to the light emitting layer of the electron injecting and transporting layer.

  The second electrode layer is usually a cathode. As a material of the second electrode layer, a material used for a general organic EL element can be used. For the cathode, it is preferable to use a conductive material having a low work function so that electrons can be easily injected. For example, magnesium alloys such as LiF (lithium fluoride), NaF (sodium fluoride), KF (potassium fluoride), MgAg, aluminum alloys such as AlLi, AlCa, AlMg, Li, Cs, Ba, Sr, Ca, etc. Examples thereof include alloys of alkali metals and alkaline earth metals.

  The other description of the second electrode layer can be the same as the contents described in the above section “5. First electrode layer”, and thus the description thereof is omitted here.

7). Others The organic EL element of the present disclosure may have the above-described members, and may have other members as necessary. About another member, the member used for a general organic EL element is employable. For example, a base member disposed on the opposite side of the light emitting layer of the first electrode layer, a sealing member that is disposed so as to cover the organic EL element and can prevent intrusion of moisture, and the like, Examples thereof include a facing substrate disposed on the surface of the electrode layer opposite to the charge injecting and transporting layer.

(A) Base Material The base material in the present disclosure is a member that supports the first electrode layer, the hole injection transport layer, the light emitting layer, the intermediate layer, the electron injection transport layer, and the second electrode layer described above.

  The base material in the present disclosure may or may not have transparency, but when taking out light from the first electrode layer side, the base material preferably has transparency.

  In the case where the substrate has a predetermined transparency, the transparency of the substrate is preferably transparent enough to transmit light emitted from the light emitting layer and display, for example, in the visible light region. The rate is preferably 80% or more, and more preferably 90% or more. Here, the transmittance | permeability of a base material can be measured with the test method of the total light transmittance of the plastic-transparent material according to JISK7361-1.

  The base material may or may not have flexibility, and can be appropriately selected according to the use of the organic EL element, but it is preferable that the base material has flexibility. This is because flexibility can be imparted to the organic EL element of the present disclosure.

  Examples of the base material include inflexible rigid materials such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plate, or flexibility such as resin film, optical resin plate, and thin glass. Examples thereof include flexible materials. In addition, the base material in this indication may be the laminated body in which the barrier layer was formed in the resin film.

  The thickness of the base material can be appropriately selected according to the type of material used for the base material, the use of the organic EL element, and the like, for example, 0.005 mm or more, and 5 mm or less. can do.

(B) Sealing member The sealing member in this indication is a member arranged so that an organic EL element may be covered.

  Examples of the material of the sealing member in the present disclosure include radical seal materials using resins such as various acrylates such as ester acrylate, urethane acrylate, epoxy acrylate, melamine acrylate, and acrylic resin acrylate, and urethane polyester, epoxy, and vinyl ether. Examples thereof include photo-curing resins such as cation-based sealing materials using resins such as thiol-ene addition-type resin-based sealing materials, and thermosetting resins.

  About the thickness of the sealing member, it can adjust suitably according to the use etc. of the organic EL element of this indication, and is not specifically limited.

(C) Opposite base material The counter base material in the present disclosure is a member disposed on the surface of the second electrode layer opposite to the electron injecting and transporting layer.

  Since the opposing base material in this indication is a member arrange | positioned on the surface on the opposite side to the light emission surface of an organic EL element, it may have transparency and does not need to have transparency.

  Examples of the material of the counter substrate in the present disclosure include inflexible rigid materials such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plate, or resin films, optical resin plates, thin glass, and the like. Examples thereof include a flexible material having flexibility. In addition, the opposing base material in this indication may be the laminated body in which the barrier layer was formed in the resin film.

8). Application The application of the organic EL element of the present disclosure is not particularly limited, and can be applied to, for example, a display device, a lighting device, a light source, and the like. In the present disclosure, the charge injecting and transporting layer disposed on the light emitting layer can be formed by a coating method. From such a viewpoint, the organic EL element of the present disclosure can have a large area and is preferably applied to a lighting device.

B. Manufacturing method of organic EL element The manufacturing method of the organic EL element of this indication is the organic EL by which the 1st electrode layer, the positive hole injection transport layer, the light emitting layer, the electron injection transport layer, and the 2nd electrode layer were laminated | stacked in this order. A manufacturing method for manufacturing an element, comprising: a light emitting layer forming step for forming the light emitting layer; an intermediate layer forming step for forming an intermediate layer on one surface of the light emitting layer; and the light emitting layer of the intermediate layer. A hole injection / transport layer forming step or an electron injection / transport layer forming step for forming the hole injection / transport layer or the electron injection / transport layer on the opposite surface; The intermediate layer composition is formed by applying the intermediate layer composition, and the intermediate layer composition contains an organic material and a solvent, and the solvent dissolves the organic material and emits the light. It is a manufacturing method that does not dissolve the luminescent material contained in the layer. The

  The present disclosure relates to a composition for a charge injection / transport layer constituting a charge injection / transport layer when a charge injection / transport layer such as a hole injection / transport layer or an electron injection / transport layer is formed on a light emitting layer using a coating method. There is an effect that it is possible to provide an organic EL element capable of suppressing dissolution and penetration of the solvent contained in the light emitting layer and the lower layer of the light emitting layer. Specifically, the above effect can be achieved by including an intermediate layer forming step of providing an intermediate layer between the light emitting layer and the charge injecting and transporting layer. In addition, by using a predetermined organic material and solvent as a material contained in the intermediate layer composition, the charge injection / transport layer performance can be obtained even when the charge injection / transport layer is mixed with an organic material in addition to the effects described above. There is an effect that it is possible to suppress a significant decrease in the.

  Hereinafter, the manufacturing method of the organic EL element of the present disclosure will be described separately for each process.

1. Intermediate layer forming step The intermediate layer forming step in the present disclosure is a step of forming an intermediate layer on one surface of the light emitting layer. Moreover, an intermediate | middle layer formation process is a process of apply | coating the composition for intermediate | middle layers which comprises an intermediate | middle layer, and forming an intermediate | middle layer, and the composition for intermediate | middle layers contains an organic material and a solvent.

  The method for applying the intermediate layer composition constituting the intermediate layer can be appropriately selected according to the type of the intermediate layer composition, the size of the organic EL element, and the like. Specific examples of the coating method include spin coating, dipping, roll coating, casting, bar coating, blade coating, spray coating, and die coating.

  In the intermediate layer forming step, it is preferable to dry the coating film of the intermediate layer composition after applying the intermediate layer composition. For example, a hot air dryer can be used for drying. The drying temperature can be appropriately adjusted according to the material of the intermediate layer composition and the thickness of the coating film. Moreover, about drying time, it can adjust suitably according to the drying temperature, the material of the composition for intermediate | middle layers, and the thickness of a coating film.

  Since the organic material contained in the intermediate layer composition can be the same as that described in the above section “A. Organic EL element 1. Intermediate layer”, description thereof is omitted here.

  The solvent contained in the intermediate layer composition is a solvent that can dissolve the organic material. Among them, the solvent is preferably a solvent that does not dissolve the light emitting material contained in the light emitting layer. In addition, about the solubility of the organic material with respect to the said solvent, the solubility of a luminescent material, etc., since it can be made to be the same as that of the content described in the above-mentioned item of "A. Organic EL element 1. Intermediate layer", description here Omitted. Examples of such solvents include nonpolar solvents, aprotic polar solvents, and protic polar solvents. Examples of the nonpolar solvent include hexane, benzene, toluene, 1,4-dioxane, chloroform, diethyl ether, diisopropyl ether, dichloromethane and the like. Examples of the aprotic solvent include N-methylpyrrolidone, tetrahydrofuran, acetone, ethyl acetate, acetonitrile, dimethylformamide, dimethyl sulfoxide and the like. Furthermore, examples of the protic polar solvent include 1-propanol, 1-butanol, isopropyl alcohol, methanol, ethanol, 2-ethoxyethanol, and the like. 1 type may be sufficient as the solvent contained in the composition for intermediate | middle layers, and 2 or more types may be sufficient as it.

2. Light emitting layer forming step The light emitting layer forming step in the present disclosure is a step of forming a light emitting layer.

  As a method for forming the light emitting layer, a general method for forming a light emitting layer can be adopted, and for example, a wet process can be used. For example, printing method, inkjet method, die coating method, spin coating method, casting method, dipping method, bar coating method, slit coating method, blade coating method, roll coating method, gravure coating method, gravure offset printing method, flexographic printing method, Examples of the application method include a spray coating method.

3. Hole injection / transport layer forming step, electron injection / transport layer forming step In the present disclosure, the hole injection / transport layer forming step and the electron injection / transport layer forming step are performed on the surface opposite to the light emitting layer of the intermediate layer. Or it is the process of forming an electron injection transport layer. The hole injecting and transporting layer forming step is a step of forming the hole injecting and transporting layer by applying the composition for hole injecting and transporting layer constituting the hole injecting and transporting layer. On the other hand, the electron injecting and transporting layer forming step is a step of forming the electron injecting and transporting layer by applying the composition for electron injecting and transporting layer constituting the electron injecting and transporting layer.

  Since the method for applying the composition for hole injection / transport layer or the composition for electron injection / transport layer can be the same as the method for applying the composition for intermediate layer described above, description thereof is omitted here.

  The composition for a hole injecting and transporting layer or the composition for an electron injecting and transporting layer usually contains a material constituting the hole injecting and transporting layer or the electron injecting and transporting layer and a solvent. In addition, the material which comprises a positive hole injection transport layer or an electron injection transport layer changes with kinds of a positive hole injection transport layer or an electron injection transport layer. In addition, about the concrete material which comprises a positive hole injection transport layer or an electron injection transport layer, said "A. Organic EL element 3. Hole injection transport layer", "A. Organic EL element 4. Electron injection transport layer. The description is omitted here because it can be the same as that described in the section.

  The solvent used in the composition for the hole injection / transport layer or the composition for the electron injection / transport layer can be appropriately selected depending on the material constituting the hole injection / transport layer or the electron injection / transport layer. The solvent used when forming a hole injection transport layer or an electron injection transport layer is mentioned.

4). Other Steps In the present disclosure, in addition to the intermediate layer forming step, the light emitting layer forming step, the hole injecting and transporting layer forming step, and the electron injecting and transporting layer forming step described above, for example, the first electrode layer forming step, the second You may have an electrode layer formation process.
Hereinafter, the first electrode layer forming step and the second electrode layer forming step will be described.

(1) 1st electrode layer formation process In this indication, you may have the process of forming the 1st electrode layer on a substrate before a light emitting layer formation process.

  The formation method of the first electrode layer can be appropriately selected according to the configuration of the organic EL element. The first electrode layer may be formed on the entire surface of the base material, and the first electrode layer is formed in a pattern. May be. Since the specific formation method of the first electrode layer can be the same as the general electrode formation method, description thereof is omitted here.

(2) Second electrode layer formation step In the present disclosure, after the hole injection transport layer formation step and the electron injection transport layer formation step, the second electrode layer is formed on the hole injection transport layer or the electron injection transport layer. You may have a process.

  The formation method of the second electrode layer can be appropriately selected according to the configuration of the organic EL element. The second electrode layer may be formed on the entire surface of the charge injecting and transporting layer, and the second electrode layer is formed in a pattern. It may be formed. Since a specific method for forming the second electrode layer can be the same as a general electrode forming method, description thereof is omitted here.

(3) Sealing member formation process In this indication, it may have a sealing member formation process which forms a sealing member which covers an organic EL element and can prevent penetration of moisture.

  The sealing member formation process in this indication should just be a process which can form a sealing member. Examples of the method for forming the sealing member include an inkjet method, a dispenser method, a spin coating method, a die coating method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, Examples include a flexographic printing method, an offset printing method, and a screen printing method.

5. Others In the present disclosure, a method of manufacturing an organic EL element having a first electrode layer forming step, a hole injection transport layer forming step, a light emitting layer forming step, an electron injection transport layer forming step, and a second electrode layer forming step in this order In addition, it is preferable to have an intermediate layer forming step between the hole injecting and transporting layer forming step and the light emitting layer forming step or between the electron injecting and transporting layer forming step and the light emitting layer forming step. .

  Moreover, the composition which does not contain a solvent may be sufficient as the composition for intermediate | middle layers used for the manufacturing method of the organic EL element of this indication for an intermediate | middle layer formation process. That is, the manufacturing method of the organic EL element of the present disclosure manufactures an organic EL element in which a first electrode layer, a hole injection transport layer, a light emitting layer, an electron injection transport layer, and a second electrode layer are stacked in this order. A method of manufacturing, wherein a light emitting layer forming step of forming the light emitting layer, an intermediate layer forming step of forming an intermediate layer on one surface of the light emitting layer, and a surface of the intermediate layer opposite to the light emitting layer A hole injecting and transporting layer forming step for forming the hole injecting and transporting layer or the electron injecting and transporting layer, or an electron injecting and transporting layer forming step. It is a step of applying the layer composition to form the intermediate layer, and the intermediate layer composition may be a manufacturing method that contains an organic material and does not contain a solvent. In this case, the organic material contained in the intermediate layer composition is preferably in a liquid state to the extent that it can be applied. Examples of such an organic material include hydrocarbons having a predetermined number of carbon atoms. Specific carbon number is 15 or more, for example, and 18 or more may be sufficient as it. On the other hand, the carbon number is, for example, 30 or less, and may be 25 or less. In addition, about hydrocarbon, since it can be the same as that of the content described in the above-mentioned item of "A. Organic EL element 1. Intermediate layer", description here is abbreviate | omitted.

  The organic EL device manufacturing method of the present disclosure described above is configured when a charge injection / transport layer such as a hole injection / transport layer or an electron injection / transport layer is formed on the light emitting layer using a coating method. The organic EL element which can suppress that the solvent contained in the composition for charge injection transport layers to melt | dissolve and osmose | permeate into the light emitting layer and the lower layer of the said light emitting layer can be provided. Specifically, the above effect can be achieved by including an intermediate layer forming step of providing an intermediate layer between the light emitting layer and the charge injecting and transporting layer. Moreover, generation | occurrence | production of the malfunction that the solvent contained in the composition for intermediate | middle layers dissolves a light emitting layer can be suppressed with the effect mentioned above because the composition for intermediate | middle layers does not contain a solvent. Furthermore, since it is not necessary to select a solvent that dissolves the organic material and does not dissolve the light emitting material contained in the light emitting layer as the solvent for the intermediate layer composition, there is an effect that the degree of freedom of each material is increased.

C. Composition for Intermediate Layer The composition for intermediate layer of the present disclosure is a composition constituting an intermediate layer formed between a light emitting layer constituting an organic EL device and a hole injection transport layer or an electron injection transport layer. The composition contains an organic material and a solvent, and the organic material is a hydrocarbon having 12 to 50 carbon atoms.

  The present disclosure uses a predetermined intermediate layer composition to form a hole injection layer by forming an intermediate layer between a light emitting layer and a hole injecting and transporting layer or between a light emitting layer and an electron injecting and transporting layer. The effect that the solvent contained in the composition for charge injection / transport layers constituting the charge injection / transport layer such as the transport layer and the electron injection / transport layer can be prevented from dissolving and penetrating into the light emitting layer and the lower layer of the light emitting layer. Play. In addition, by using a predetermined organic material and solvent as a material included in the intermediate layer composition, in addition to the effects described above, the charge injection / transport layer performance can be improved even when the charge injection / transport layer is mixed with an organic material. There is an effect that a significant decrease can be suppressed.

  In addition, about the composition for intermediate | middle layers, it shall be the same as that of the content described in the said "A. organic EL element 1. intermediate | middle layer" and the said "B. manufacturing method of organic EL element 1. intermediate | middle layer formation process". Therefore, the description is omitted here.

  Moreover, the composition for intermediate | middle layers of this indication may be a composition which does not contain a solvent. That is, the composition for an intermediate layer of the present disclosure is a composition constituting an intermediate layer formed between a light-emitting layer constituting an organic EL device and a hole injection / transport layer or an electron injection / transport layer. The product may be a composition containing an organic material and no solvent, and the organic material is a hydrocarbon having 12 to 50 carbon atoms. In this case, the organic material contained in the intermediate layer composition is preferably in a liquid state to the extent that it can be applied. Examples of such an organic material include hydrocarbons having a predetermined number of carbon atoms. Specific carbon number is 15 or more, for example, and 18 or more may be sufficient as it. On the other hand, the carbon number is, for example, 30 or less, and may be 25 or less. In addition, about hydrocarbon, since it can be the same as that of the content described in the above-mentioned item of "A. Organic EL element 1. Intermediate layer", description here is abbreviate | omitted.

  In addition, about the effect of the said composition for intermediate | middle layers, since it can be made to be the same as that of the content described in the term of the said "B. manufacturing method of an organic EL element", description here is abbreviate | omitted.

Hereinafter, the present disclosure will be specifically described using examples and comparative examples.
In addition, unless otherwise indicated, the application | coating process and drying process in a following example and the comparative example were performed by inert gas atmosphere (oxygen concentration 1 ppm or less, moisture concentration 1 ppm or less).

[Example 1]
On a glass substrate of 25 mm × 25 mm × 0.7 mm (manufactured by Sanyo Vacuum Co., Ltd.), an ITO substrate having a thickness of 150 nm was patterned as an anode to obtain an ITO substrate. This ITO substrate was ultrasonically cleaned in the order of neutral detergent and ultrapure water, and UV ozone cleaning was performed for 10 minutes.

  On the ITO substrate, a hole injection layer was formed by applying a PEDOT-PSS thin film (thickness: 30 nm) by spin coating in the atmosphere. The PEDOT-PSS thin film was formed by applying a PEDOT-PSS solution (manufactured by Bayer, Baytron P AI 4083). After application of the solution, it was dried at 200 ° C. for 30 minutes in the air using a hot plate in order to evaporate the solvent.

  On the hole injection layer, poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4′-) which is a conjugated polymer material is used as a hole injection transport layer. (N- (4-sec-butylphenyl)) diphenylamine)] (TFB) thin film (thickness: 10 nm) was formed. The TFB thin film was formed by applying a solution in which TFB was dissolved in xylene at a concentration of 0.4 wt% by spin coating. After application of the solution, it was dried at 200 ° C. for 30 minutes using a hot plate in order to evaporate the solvent.

  Next, on the hole injecting and transporting layer, Tris [2- (p-tolyl) pyridine] iridium (III) (Ir (mppy) 3) is contained as a light emitting dopant as a light emitting layer, and Poly (N− A mixed thin film (thickness: 80 nm) containing vinylcarbazole) (PVK) and 1,3-bis [(4-tert-butylphenyl) -1,3,4-oxydiazole] phenylene (OXD-7) as a host was formed. The mixed thin film was formed by applying a solution obtained by dissolving Ir (mppy) 3, PVK, and OXD-7 at a concentration of 1.8 wt% in toluene by spin coating. The solid content in the solution was adjusted to PVK: OXD-7: Ir (mppy) 3 = 70: 20: 10 by weight ratio. After application of the solution, it was dried at 110 ° C. for 30 minutes using a hot plate in order to evaporate the solvent.

  Nonadecane was heated to 40 ° C. to be in a liquid state, and applied on the light emitting layer by a spin coating method to form an intermediate layer. After application, it was stationary until it reached room temperature. The film thickness of the intermediate layer was 10 nm.

A Tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (3TPYB) thin film (thickness: 30 nm) was formed on the intermediate layer as an electron injecting and transporting layer. The 3TPYB thin film was obtained by applying a solution dissolved in 1-butanol at a concentration of 0.5 wt% by spin coating to form a film. After application of the solution, it was dried under reduced pressure at room temperature for 30 minutes in an environment of 10 ⁻⁴ Pa.

Lithium fluoride (0.5 nm) was formed on the electron injecting and transporting layer. Subsequently, Al (thickness: 100 nm) was formed into a film as a cathode. Sodium fluoride and Al were formed by resistance heating vapor deposition in vacuum (1 × 10 ⁻⁴ Pa). After forming the cathode, it was sealed in the glove box using alkali-free glass and a UV curable epoxy adhesive.
Thereby, the organic EL element of this indication was obtained.

[Example 2]
An organic EL device was obtained in the same manner as in Example 1 except that docosan was heated to 50 ° C. to be in a liquid state and applied to the light emitting layer by spin coating to form an intermediate layer.

[Comparative example]
An organic EL device was obtained in the same manner as in Example 1 except that no intermediate layer was formed.

[Evaluation]
With respect to the organic EL elements of Examples 1 and 2 and Comparative Example, a voltage was applied between the anode and the cathode, and current efficiency at 10 mA / cm ² was measured. Further, the current was set so that the luminance was 1000 cd / m ^2, and the time (luminance half-life) during which the luminance decreased to 500 cd / m ² when the constant current was continuously applied was measured. The measurement results are shown in Table 1. The measurement results in Table 1 are relative ratios when the current efficiency and the luminance half life of the comparative example are each 100.

  As shown in Table 1, the organic EL elements of Examples 1 and 2 having an intermediate layer exhibited inferior and good characteristics as compared with the organic EL elements of Comparative Examples having no intermediate layer. As a result, the organic EL elements of Examples 1 and 2 have an intermediate layer, and thus when the composition containing the solvent is applied onto the intermediate layer, the penetration of the solvent into the light emitting layer is suppressed. This is considered to be caused by suppressing dissolution of the light emitting layer by the solvent. In addition, as shown in Table 1, the organic EL elements of Examples 1 and 2 did not deteriorate in performance due to the provision of the intermediate layer. This is considered due to the fact that the intermediate layer formed in Examples 1 and 2 is electrically inactive.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... 1st electrode layer 3 ... Hole injection transport layer 3a ... Hole injection layer 3b ... Hole transport layer 4 ... Light emitting layer 5 ... Intermediate | middle layer 6 ... Electron injection transport layer 6a ... Electron injection layer 6b ... Electron transport layer 7 ... Second electrode layer 100 ... Organic EL element

Claims (11)

The first electrode layer, the hole injecting and transporting layer, the light emitting layer, the electron injecting and transporting layer, and the second electrode layer are organic electroluminescent elements laminated in this order,
Between the hole injecting and transporting layer and the light emitting layer, or between the electron injecting and transporting layer and the light emitting layer, and having an intermediate layer,
The organic electroluminescent element in which the said intermediate | middle layer contains an organic material.   The organic electroluminescent element according to claim 1, wherein the organic material is a hydrocarbon having 12 to 50 carbon atoms.   The organic electroluminescent element according to claim 1, wherein the organic material is a hydrocarbon oil.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the intermediate layer has a band gap of 3.0 eV or more.   The organic electroluminescent element according to any one of claims 1 to 4, wherein the organic material is dissolved in a solvent that does not dissolve the light emitting material contained in the light emitting layer.   The organic light-emitting device according to claim 5, wherein the light-emitting layer has a remaining film ratio of 70% or more with respect to a solvent contained in the composition for forming the intermediate layer.   The organic electroluminescence device according to claim 1, wherein the intermediate layer is disposed between the electron injecting and transporting layer and the light emitting layer. The first electrode layer, the hole injecting and transporting layer, the light emitting layer, the electron injecting and transporting layer, and the second electrode layer are a method for producing an organic electroluminescence element for producing an organic electroluminescence element laminated in this order,
A light emitting layer forming step of forming the light emitting layer;
An intermediate layer forming step of forming an intermediate layer on one surface of the light emitting layer;
A hole injection / transport layer forming step or an electron injection / transport layer forming step of forming the hole injection / transport layer or the electron injection / transport layer on the surface of the intermediate layer opposite to the light emitting layer,
The intermediate layer forming step is a step of applying the intermediate layer composition constituting the intermediate layer to form the intermediate layer,
The intermediate layer composition contains an organic material and a solvent,
The said solvent melt | dissolves the said organic material, The manufacturing method of an organic electroluminescent element which does not melt | dissolve the luminescent material which the said light emitting layer contains. The first electrode layer, the hole injecting and transporting layer, the light emitting layer, the electron injecting and transporting layer, and the second electrode layer are a method for producing an organic electroluminescence element for producing an organic electroluminescence element laminated in this order,
A light emitting layer forming step of forming the light emitting layer;
An intermediate layer forming step of forming an intermediate layer on one surface of the light emitting layer;
A hole injection / transport layer forming step or an electron injection / transport layer forming step of forming the hole injection / transport layer or the electron injection / transport layer on the surface of the intermediate layer opposite to the light emitting layer,
The intermediate layer forming step is a step of applying the intermediate layer composition constituting the intermediate layer to form the intermediate layer,
The said composition for intermediate | middle layers contains an organic material, and does not contain a solvent, The manufacturing method of an organic electroluminescent element. It is a composition constituting an intermediate layer formed between a light emitting layer constituting an organic electroluminescence element and a hole injection transport layer or an electron injection transport layer,
The composition contains an organic material and a solvent,
The composition for intermediate | middle layers whose said organic material is a C12-C50 hydrocarbon. It is a composition constituting an intermediate layer formed between a light emitting layer constituting an organic electroluminescence element and a hole injection transport layer or an electron injection transport layer,
The composition contains an organic material and no solvent,
The composition for intermediate | middle layers whose said organic material is a C12-C50 hydrocarbon.

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