Method for manufacturing an organic electroluminescent element and organic electroluminescent element

Abstract

To provide a manufacturing method of an organic electroluminescent element by a wet type film production, in which an electric conduction characteristic of a functional layer formed in a bank is not largely modulated from the electric conduction characteristic of an original material.SOLUTION: A manufacturing method of an organic electroluminescent element, comprises the steps of, in order: forming a structure patterned by a photo-lithography method by applying a photosensitive composition A onto a substrate including a patterned electrode layer; applying a functional component B onto the substrate having the structure; and obtaining a functional film by vaporizing an organic solvent of the functional component B by drying. The photosensitive composition A is a component containing at least one kind of high-performance material containing a fluorine atom, and the functional component B is a component containing at least one kind of electronic acceptability chemical compound containing a fluorine atom and at least one kind of organic solvent, in which Ra satisfies 17.0 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an organic electroluminescent element, and to an organic electroluminescent element manufactured using the said manufacturing method. [Background technology]

[0002] While the common method for manufacturing organic electroluminescent devices involves depositing organic materials into thin films using vacuum deposition and then stacking them, in recent years, research has been actively pursuing wet deposition methods, which involve coating and stacking organic materials in solution, as a manufacturing method with superior material utilization efficiency.

[0003] In the manufacturing of organic electroluminescent devices, particularly organic EL displays, by wet film deposition, a method has been investigated in which each pixel is partitioned by a partition called a bank, and an ink, which is an organic electroluminescent device forming composition, is printed onto a minute region within the bank using methods such as inkjet printing to form the functional film that constitutes the organic electroluminescent device.

[0004] However, in organic electroluminescent devices in which structures such as banks exist adjacent to the functional layer, the functional layer interacts with the bank material, preventing the material from exhibiting its inherent performance. Generally, organic electroluminescent devices manufactured within a bank have the problem of having lower performance compared to organic electroluminescent devices without a bank (Patent Document 1).

[0005] The performance of an organic electroluminescent device (OLED) can vary due to various factors, but generally, the external quantum efficiency ηext is expressed by the following equation (1), using the electron-hole balance factor γ, the generation efficiency χ of excitons that can contribute to light emission, the internal quantum efficiency φ of the light-emitting layer, and the light extraction efficiency ηоut, which represents the proportion of light that escapes to the outside of the OLED. (Shizuka Tokito, Chihaya Adachi, Hideyuki Murata, "Organic EL Displays", Ohmsha, 2004) ηext = γ × χ × φ × ηout (1) In this context, the carrier balance factor γ represents the degree to which the number of holes coming from the anode and the number of electrons coming from the cathode are in agreement, and is an important factor in determining the luminescence efficiency of an organic electroluminescent device.

[0006] In organic electroluminescent devices, the functional layer that comes into contact with and interacts with the bank is susceptible to electrical traps due to the inclusion of impurities, for example, which can easily alter its electrical conductivity. This can cause the carrier balance factor γ, represented by equation (1), to change, leading to a decrease in luminescence efficiency.

[0007] Thus, organic electroluminescent devices that include a functional layer adjacent to the bank have the problem that their electrical conductivity characteristics can easily change due to various factors, which degrades the performance of the organic electroluminescent device. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 6535977 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a method for manufacturing an organic electroluminescent element by wet film deposition in which the electrical conductivity characteristics of the functional layer coated in the bank do not change significantly from the original electrical conductivity characteristics of the material. Another object of the present invention is to provide an organic electroluminescent element manufactured by the above manufacturing method. [Means for solving the problem]

[0010] The inventors discovered that an electron-accepting compound containing fluorine atoms in an organic electroluminescent element formation composition interacts with a fluorine component in a liquid-repellent bank, significantly altering the electrical conductivity of the functional layer from the material's inherent properties. They also found that the compatibility between the electron-accepting compound and the organic solvent in the composition is crucial for resolving this issue. Through diligent investigation, they discovered that using a composition such that the semi-empirical solubility Ra of the electron-accepting compound and the organic solvent in a three-dimensional space according to Hansen's solubility parameter is 17.0 or less suppresses voltage fluctuations when manufacturing an organic electroluminescent element including a functional layer adjacent to the bank. Ra = [4 × (Ds - Dd)] 2 +(Ps-Pd) 2 +(Hs-Hs) 2 ] 1 / 2 And, (Ds, Ps, Hs) are the dispersion, polarity, and hydrogen bonding terms of the Hansen solubility parameter of an organic solvent. (Dd, Pd, Hd) are the dispersion, polarity, and hydrogen bonding terms of the Hansen solubility parameter for electron-accepting compounds.

[0011] In other words, the present invention has the following configuration.

[0012] [1] A step of applying a liquid-repellent photosensitive composition A onto a substrate having a patterned electrode layer, and forming a patterned structure by photolithography, A step of applying a functional composition B containing an organic solvent onto a substrate having the aforementioned structure, A method for manufacturing an organic electroluminescent element, comprising the steps of: volatilizing the organic solvent of the functional composition B by drying to obtain a functional film, in this order, The photosensitive composition A is a composition comprising at least one functional material containing a fluorine atom, The functional composition B is a composition comprising at least one electron-accepting compound containing a fluorine atom and at least one organic solvent. The Hansen solubility parameters (dispersion term: Ds, polarity term: Ps, hydrogen bonding term: Hs) of at least one organic solvent contained in the functional composition B, In relation to the relationship between the Hansen solubility parameter (dispersion term: Dd, polarity term: Pd, hydrogen bonding term: Hd) of at least one electron-accepting compound containing the fluorine atom included in the functional composition B, Solubility Ra = [4 × (Ds - Dd)] (including empirical rules) 2 +(Ps-Pd) 2 +(Hs-Hs) 2 ] 1 / 2 It is characterized by satisfying the condition that is 17.0 or less. A method for manufacturing an organic electroluminescent element. [2] The method for producing an organic electroluminescent element according to [1], characterized in that the content of the organic solvent that satisfies the relationship of Ra is 30% by mass or more relative to the entire functional composition B. [3] A method for producing an organic electroluminescent element according to [1] or [2], characterized in that the content of the electron-accepting compound containing the fluorine atom is 0.01% by mass or more relative to the entire functional composition B. [4] A method for producing an organic electroluminescent element according to any one of [1] to [3], characterized in that the electron-accepting compound containing the fluorine atom is a compound having a crosslinkable substituent. [5] The method for producing an organic electroluminescent element according to [4], characterized in that the crosslinkable substituent is a substituent selected from substituents containing a benzocyclobutene ring, a naphthocyclobutene ring, or an oxetane ring, a vinyl group, an acrylic group, or a styryl group which may have an alkyl substituent. [6] A method for manufacturing an organic electroluminescent element according to any one of [1] to [5], characterized in that the drying is vacuum drying, and in the vacuum drying, the time until the vapor pressure of the organic solvent having the lowest vapor pressure among the organic solvents that satisfy the relationship Ra is reached is 10 seconds or more and 600 seconds or less. [7] An organic electroluminescent element manufactured by any one of the methods described in [1] to [6]. [Effects of the Invention]

[0013] The manufacturing method of the present invention suppresses the deviation of the electrical conductivity characteristics of the layer (functional layer) containing an electron-accepting compound with fluorine atoms, which is formed by the functional material B coated in the bank, from the original electrical conductivity characteristics of the electron-accepting compound. As a result, it is possible to manufacture an organic electroluminescent element without degrading the performance inherently possessed by the functional layer. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional diagram showing an example of the structure of the organic electroluminescent element of the present invention. [Modes for carrying out the invention]

[0015] Hereinafter, embodiments for carrying out the present invention will be described with reference to the figures and other drawings. The embodiments described below are just one embodiment for illustrating the present invention and are not intended to be interpreted as limiting the present invention, and not all configurations described in each embodiment are necessarily essential for solving the problems of the present invention. In this specification, when the expression "~" is used, it is used to include the numerical values ​​or physical properties before and after it.

[0016] Furthermore, in this specification, when the composition of the present invention is used as an ink ejected from a nozzle such as an inkjet, it may be simply referred to as "ink." When the composition of the present invention is used as an ink ejected from a nozzle such as an inkjet, and is ejected from the nozzle and applied to an area surrounded by a partition layer, the ink in the area surrounded by the partition layer may be referred to as a liquid or liquid film, and the ink ejected from the nozzle may be referred to as a droplet.

[0017] A liquid film within a region surrounded by a partition layer (bank) may also be referred to as a liquid or liquid film when the solvent composition ratio of the liquid film changes due to the evaporation of the solvent after drying. A film containing a functional material obtained by coating and forming a film with the functional composition B of the present invention, and then drying it by evaporating the organic solvent, is called a functional film or functional layer. Furthermore, a film containing an organic compound that does not contain a solvent or is dried by substantially evaporating the solvent is called an organic film. A functional film is a type of organic film.

[0018] In this specification, "bank" refers to a structure obtained by patterning a film manufactured using a photosensitive composition using a general photolithography method, thereby forming a film having partitioned micro-regions (also called pixels). The partitioned micro-regions of this structure are surrounded by bank walls of a certain height, and the entire area of ​​these walls is referred to as the bank side. Furthermore, the photosensitive composition manufactured for the above purpose may be simply referred to as a resist.

[0019] In many cases where organic EL displays are manufactured using a wet process, the resist used in this process is liquid-repellent, preventing the applied functional ink from overflowing. The resist used to manufacture such a liquid-repellent resist is sometimes called a liquid-repellent resist. Furthermore, a film manufactured using this liquid-repellent resist, and then exposed and developed without using a patterning mask, is called a liquid-repellent resist film.

[0020] [Manufacturing method for organic electroluminescent element] In the method for manufacturing an organic electroluminescent device, a photosensitive composition A having liquid repellency is applied onto a substrate having a patterned electrode layer, a step of forming a patterned structure by a photolithography method is performed, a functional composition B is applied onto the substrate having the structure, and a step of obtaining a functional film by volatilizing the organic solvent component of the functional composition B by drying under reduced pressure are included in this order. The photosensitive composition A is a composition containing at least one functional material containing a fluorine atom, the functional material B is a composition containing at least one electron-accepting compound containing a fluorine atom and at least one organic solvent, and in the relationship between the Hansen solubility parameters (dispersion term: Ds, polar term: Ps, hydrogen bonding term: Hs) of at least one organic solvent among the organic solvents contained in the functional composition B and the Hansen solubility parameters (dispersion term: Dd, polar term: Pd, hydrogen bonding term: Hd) of at least one electron-accepting compound containing a fluorine atom among the electron-accepting compounds containing a fluorine atom contained in the functional composition B, the solubility Ra = [4×(Ds - Dd) 2 +(Ps - Pd) 2 +(Hs - Hs) 2 1 / 2 is 17.0 or less, which is a characteristic of the method for manufacturing an organic electroluminescent device.

[0021] The composition included in the present invention is characterized in that the solubility Ra of the electron-accepting compound containing a fluorine atom and the organic solvent in the three-dimensional space of the Hansen solubility parameter is 17.0 or less. In the Hansen solubility parameter, the smaller Ra is, the more similar the solubility is. That the Ra of the organic solvent and the electron-accepting compound containing a fluorine atom is small means that the electron-accepting compound is easily soluble in the organic solvent.

[0022] ​When electron-accepting compounds containing fluorine atoms are poorly soluble in organic solvents, the electron-accepting compounds begin to aggregate during the drying process of the functional composition B ink (hereinafter also referred to as "functional ink") discharged into the bank, resulting in a problem where they do not spread uniformly within the film. Furthermore, when the functional ink is in contact with a liquid-repellent bank containing fluorine atoms, the electron-accepting compounds are attracted to the liquid-repellent components of the liquid-repellent bank, causing them to concentrate on the outside of the functional film. As a result, a deficiency of electron-accepting compounds occurs throughout the functional film, leading to a significant decrease in its electrical conductivity.

[0023] In this invention, in order to improve the solubility of electron-accepting compounds containing fluorine atoms in functional inks and to achieve a state in which they remain uniformly dissolved in organic solvents until the end of drying, a functional ink is used in which the solubility Ra of the electron-accepting compound and the organic solvent in the three-dimensional space of the Hansen solubility parameter is 17.0 or less. When this functional ink is applied to a bank containing a fluorine atom-containing resin to form a film, an organic electroluminescent device can be manufactured without losing the original performance of the electron-accepting compound containing fluorine atoms.

[0024] In the present invention, in order to improve the solubility of the electron-accepting compound and ensure that it remains uniformly dissolved in the organic solvent until the end of drying, the solubility Ra of the electron-accepting compound containing a fluorine atom in the organic solvent in functional composition B is preferably 16.5 or less, and more preferably 16.0 or less.

[0025] If functional composition B contains electron-accepting compounds containing two or more fluorine atoms and / or two or more organic solvents, the Ra value is determined for each combination of electron-accepting compounds and organic solvents containing fluorine atoms. In this invention, it is sufficient that the Ra value of at least one of these combinations is 17.0 or less. For example, if functional composition B contains an electron-accepting compound containing two types of fluorine atoms and two types of organic solvents, a total of four Ra ​​values ​​can be determined for each combination of electron-accepting compound containing fluorine atoms and organic solvent. In the present invention, it is sufficient that at least one of these four Ra ​​values ​​is 17.0 or less.

[0026] The Hansen solubility parameter is a parameter used to predict the solubility of a substance. In this invention, the Hansen solubility parameters of organic solvents (dispersion term: Ds, polarity term: Ps, hydrogen bonding term: Hs) and the Hansen solubility parameters of electron-accepting compounds (dispersion term: Dd, polarity term: Pd, hydrogen bonding term: Hd) are calculated from the molecular structural formula using the calculation software HSPiP (Hansen Solubility Parameter in Practice). These values ​​are expressed in the following formula Ra = [4 × (Ds - Dd)] 2 +(Ps-Pd) 2 +(Hs-Hs) 2 ] 1 / 2 By applying this, we can find Ra.

[0027] [Photosensitive composition A] The photosensitive composition A in the present invention is a composition comprising at least one functional material containing a fluorine atom, and can form a patterned structure by photolithography. The photosensitive composition A may be either positive or negative, but the negative type is preferred from the viewpoint of liquid repellency. A preferred embodiment of at least one functional material containing a fluorine atom is the same as the embodiment described later for (D) the liquid repellent.

[0028] When photosensitive composition A is of the negative type, it is preferable that it contains (A) a photopolymerization initiator, (B) an alkali-soluble resin, (C) a photopolymerizable compound, and (D) a liquid repellent.

[0029] (A) Photopolymerization initiator (A) The photopolymerization initiator is included to absorb ultraviolet light and (C) promote the polymerization reaction of the photopolymerizable compound. The photopolymerization initiator used in this application is not particularly limited, but oxime ester-based photopolymerization initiators are preferred because they moderately absorb ultraviolet light (i-rays) with a wavelength of 350-400 nm from the light source of the exposure machine, promote the polymerization reaction, and improve liquid repellency.

[0030] For example, photopolymerization initiators described in Japanese Patent No. 4454067, International Publication 2002 / 100903, International Publication 2012 / 45736, International Publication 2015 / 36910, International Publication 2006 / 18973, International Publication 2008 / 78678, Japanese Patent No. 4818458, International Publication 2005 / 80338, International Publication 2008 / 75564, International Publication 2009 / 131189, International Publication 2009 / 131189, International Publication 2010 / 133077, International Publication 2010 / 102502, and International Publication 2012 / 68879 can be used.

[0031] Furthermore, the content of the photopolymerization initiator is not particularly limited, but is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and usually 15% by mass or less, preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less, in the total solid content of the resist. Setting it above the lower limit tends to produce sufficient liquid repellency, and setting it below the upper limit tends to produce good developability.

[0032] (B) Alkali-soluble resin (B) The alkali-soluble resin is not particularly limited as long as it can be developed with an alkaline developer. Examples of alkali-soluble resins include various resins having carboxyl groups or hydroxyl groups, but those having carboxyl groups are preferred from the viewpoint of excellent developability. Furthermore, alkali-soluble resins having ethylenically unsaturated groups are preferred because they result in good verticality of the bank sides, suppress the outflow of the liquid repellent due to thermal melting of the bank, and make it easier to maintain liquid repellency.

[0033] (B) The specific structure of the alkali-soluble resin is not particularly limited, but epoxy (meth)acrylate resin (B1) and / or acrylic copolymer resin (B2) are preferred. Here, epoxy (meth)acrylate resin (B1) is a resin obtained by adding an acid or ester compound having an ethylenically unsaturated bond (ethylenically double bond) to an epoxy resin having an aromatic ring in its main chain, and further adding a polybasic acid or its anhydride. Furthermore, a resin obtained by reacting the carboxyl group of the resin obtained in the above reaction with a compound having a further reactive functional group is also included in epoxy (meth)acrylate resin (B1). For example, alkali-soluble resins described in International Publication Nos. 2004 / 81621, 2008 / 129986, 2008 / 153000, 2018 / 43746, 2018 / 101314, and 2021 / 90836 can be used.

[0034] The content of (B) alkali-soluble resin in the liquid-repellent resist of the present invention is not particularly limited, but is usually 5% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, particularly preferably 50% by mass or more, relative to the total solid content, and usually 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass or less. Setting it above the lower limit tends to result in a good partition shape, and setting it below the upper limit tends to improve liquid repellency.

[0035] (C) Photopolymerizable compound (C) Photopolymerizable compounds are thought to improve the curability of the resist film and enhance its liquid repellency. The photopolymerizable compounds used here are not limited to the following. Generally, this refers to compounds having one or more ethylenically unsaturated bonds in the molecule, but it is preferable that the compounds have two or more ethylenically unsaturated bonds in the molecule, in terms of polymerizability, crosslinkability, and the resulting difference in developer solubility between the exposed and unexposed areas. Furthermore, it is even more preferable that the unsaturated bonds are derived from (meth)acryloyloxy groups, i.e., (meth)acrylate compounds. Examples of photopolymerizable compounds include esters of aliphatic polyhydroxy compounds and unsaturated carboxylic acids; esters of aromatic polyhydroxy compounds and unsaturated carboxylic acids; and esters obtained by the esterification reaction of polyhydric hydroxy compounds such as aliphatic polyhydroxy compounds and aromatic polyhydroxy compounds with unsaturated carboxylic acids and polybasic carboxylic acids. However, from the viewpoint of liquid repellency, esters of aliphatic polyhydroxy compounds and unsaturated carboxylic acids are preferred. For example, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-tris(meth)acryloyloxymethylethylphthalic acid, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate are more preferred.

[0036] The content of (C) the photopolymerizable compound in the liquid-repellent resist of the present invention is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, usually 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to the total solid content. Setting it above the lower limit tends to result in good verticality of the partition wall side surface during exposure, and setting it below the upper limit tends to result in good developability.

[0037] (D) Liquid repellent Photosensitive composition A includes (D) a liquid repellent, which is at least one functional material containing a fluorine atom. Preferably, the at least one functional material containing a fluorine atom is a material containing a fluorine atom-containing resin having a crosslinking group. By including a fluorine atom-containing resin having a crosslinking group, liquid repellency can be imparted to the surface of the bank, thereby preventing inks in adjacent minute areas from mixing when functional inks are applied.

[0038] Examples of crosslinking groups include epoxy groups and ethylenically unsaturated groups, with ethylenically unsaturated groups being preferred from the viewpoint of suppressing the outflow of the liquid-repellent component of the developer. By using a liquid repellent having a crosslinking group, the crosslinking reaction on the surface of the formed resist film can be accelerated when exposed, making it less likely for the liquid repellent to flow out during the development process, and as a result, the resulting bank can also exhibit high liquid repellency. Furthermore, because it is a fluorine atom-containing resin, the fluorine atom-containing resin tends to orient itself on the surface of the partition wall, which helps to prevent bleeding and mixing of functional inks.

[0039] Fluorine atoms can be incorporated in the form of, for example, fluoroalkyl groups, fluoroalkenyl groups, or fluoroalkylene groups. Of these, fluoroalkyl groups and fluoroalkylene groups are preferred from the viewpoint of preventing liquid repellency and bleeding or mixing of functional inks, with fluoroalkyl groups being more preferred.

[0040] Furthermore, it is desirable that the liquid repellent be an acrylic copolymer. Being an acrylic copolymer tends to prevent the bleeding and mixing of functional inks.

[0041] (D) The content of the liquid repellent is not particularly limited, but is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, relative to the total solid content, and is usually 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. Setting it above the lower limit tends to show high liquid repellency, and setting it below the upper limit tends to suppress leakage into minute areas.

[0042] (Other additives) In addition to the ethylenically unsaturated compound of component (A), the photopolymerization initiator of component (B), the alkali-soluble binder of component (C), and the liquid repellent of component (D), surfactants, colorants, ultraviolet absorbers, polymerization inhibitors, antioxidants, developer improvers, silane coupling agents, epoxy compounds, and other resins may be appropriately blended.

[0043] Furthermore, the liquid-repellent resist is used in which each component is dissolved or dispersed in a solvent as appropriate. There are no particular restrictions on the solvent, but examples of organic solvents include those listed below. Glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; Glycol dialkyl ethers such as diethylene glycol ethyl methyl ether and diethylene glycol diethyl ether; Glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and 3-methoxybutyl acetate; Glycol diacetates such as 1,3-butylene glycol diacetate, 1,4-butanediol diacetate, and 1,6-hexanol diacetate; Alkoxycarboxylic acids such as ethyl acetate, propyl acetate, butyl acetate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, and ethyl 3-methoxypropionate.

[0044] Of these, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and 3-methoxy-1-butyl acetate are preferred.

[0045] [Functional composition B] Functional composition B used in the present invention comprises at least one electron-accepting compound containing a fluorine atom and at least one organic solvent.

[0046] <organic solvents> The solvents that can be used in the present invention will be described below with examples.

[0047] There are no particular limitations on the solvent used in functional composition B of the present invention, but it is preferable that at least one aromatic organic solvent is included in order to effectively dissolve the functional material. The aromatic organic solvent is not particularly limited, but preferably includes water-insoluble aromatic solvents such as aromatic hydrocarbon solvents, aromatic ester solvents, aromatic ether solvents, and aromatic ketone solvents.

[0048] Preferred aromatic hydrocarbon solvents include benzene derivatives, naphthalene derivatives, hydrogenated naphthalene derivatives, biphenyl derivatives, and diphenylmethane derivatives.

[0049] While not particularly limited, benzene derivatives are preferred that have a total number of carbon atoms of substituents of 2 to 12 and have linear, branched, or cyclic alkyl groups as substitutions. Examples include n-ethylbenzene, 1,3,5-trimethylbenzene, n-propylbenzene, isopropylbenzene, 1,3-diisopropylbenzene, 1,3,5-triisopropylbenzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, n-pentylbenzene, n-hexylbenzene, n-heptylbenzene, n-octylbenzyl, n-nonylbenzene, n-decylbenzene, dodecylbenzene, and cyclohexylbenzene.

[0050] While not particularly limited, naphthalene derivatives are preferred if they have a total number of carbon atoms between 2 and 6 and have linear, branched, or cyclic alkyl groups as substitutions. Examples include 1-methylnaphthalene, 2-methylnaphthalene, 1-ethylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, 2,6-dimethylnaphthalene, 2,7-diisopropylnaphthalene, 1-butylnaphthalene, 2-cyclohexylnaphthalene, and 1-phenylnaphthalene.

[0051] Examples of naphthalene hydrogenated derivatives are not particularly limited, but include tetralin, 1,2-dihydronaphthalene, 1,4-dihydronaphthalene, etc., which may be substituted with alkyl groups having 1 to 6 carbon atoms.

[0052] While there are no particular limitations on the biphenyl derivatives, biphenyl derivatives substituted with alkyl groups having 1 to 6 carbon atoms are preferred, such as 3-ethylbiphenyl, 4-isopropylbiphenyl, and 4-butylbiphenyl.

[0053] While there are no particular limitations on the diphenylmethane derivative, diphenylmethane derivatives substituted with alkyl groups having 1 to 6 carbon atoms are preferred, such as 1,1-diphenylethane, 1,1-diphenylpentane, 1,1-diphenylhexane, 1,1-bis(3,4-dimethylphenyl)ethane, and benzyltoluene.

[0054] Examples of aromatic ester solvents include benzoic acid ester solvents, phenylacetic acid ester solvents, and phthalic acid ester solvents.

[0055] The benzoic acid ester solvent is a compound having an ester bond with benzoic acid, and a compound in which benzoic acid, which may have substituents, and an alcohol having 1 to 12 carbon atoms can be used. Although not particularly limited, preferred substituents are linear, branched, or cyclic alkyl groups having 1 to 12 carbon atoms, linear, branched, or cyclic alkoxy groups having 1 to 12 carbon atoms, and aromatic substituents having 6 to 12 carbon atoms. There may be multiple substituents, and in the case of multiple substituents, the total number of carbon atoms as substituents is preferably 2 to 12. Examples of benzoic acid ester solvents include ethyl benzoate, n-butyl benzoate, n-pentyl benzoate, isoamyl benzoate, n-hexyl benzoate, 2-ethylhexyl benzoate, benzyl benzoate, methyl 4-methylbenzoate, methyl 3-methylbenzoate, methyl 2-methylbenzoate, ethyl 4-methylbenzoate (ethyl p-toluate), ethyl 3-methylbenzoate, ethyl 2-methylbenzoate, and ethyl 4-methoxybenzoate.

[0056] Examples of phenylacetic acid ester solvents are not particularly limited, but include ethyl phenylacetate.

[0057] Examples of phthalate ester solvents, though not particularly limited, include dimethyl phthalate, diethyl phthalate, and dibutyl phthalate.

[0058] Other preferred aromatic ester solvents include 2-phenoxyethyl acetate and 2-phenoxyethyl isobutyrate.

[0059] Aromatic ether solvents are compounds having an aromatic ring and an ether bond, and are not particularly limited, but include the following: Examples of benzene derivatives having one linear, branched, or cyclic alkyl group with 1 to 12 carbon atoms and one ether bond include anisole, 4-methylanisole, butylphenyl ether, hexylphenyl ether, diphenyl ether, benzylphenyl ether, and dibenzyl ether. Examples of diphenyl ether derivatives substituted with linear or branched alkyl groups having 1 to 6 carbon atoms include 2-phenoxytoluene, 3-phenoxytoluene, and 4-phenoxytoluene; Examples of benzene derivatives having two ether bonds with linear or branched alkyl groups having 1 to 6 carbon atoms include 1,4-diethoxybenzene and 1-ethoxy-4-hexyloxybenzene; Other aromatic ether solvents include 2-phenoxyethanol and phenoxyethoxyethanol.

[0060] Aromatic ketone solvents are compounds that have an aromatic ring and a ketone structure, such as 1-acetylnaphthalene, propiophenone, and 4'-ethylpropiophenone.

[0061] In order to effectively dissolve electron-accepting compounds containing fluorine atoms, the content of the organic solvent that satisfies the above Ra relationship is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, relative to the total functional composition B.

[0062] Furthermore, the solvent may contain a surface modifier to control surface tension. By adding a small amount of the surface modifier to the liquid, functionality can be imparted to the liquid surface after application, or to the solid surface obtained by application. Examples of functions that can be imparted include liquid repellency, non-stickiness, wettability, smoothness, dispersibility, and defoaming.

[0063] Materials that can be used as surface modifiers are preferably those that tend to segregate on the liquid surface. Specifically, these include materials containing silicon or fluorine (polymers, oligomers, low molecular weight materials), paraffin, or surfactants. The surfactant referred to herein is a substance having an amphiphilic chemical structure with a hydrophilic portion (group) and a hydrophobic portion (group), and is used in a wide range of applications such as dispersants, foaming agents, defoaming agents, emulsifiers, food additives, humectants, antistatic agents, wettability enhancers, lubricants, and rust inhibitors. Such surfactants are broadly classified into those with cationic, anionic, or amphoteric hydrophilic portions and those with nonionic portions. In the present invention, nonionic surfactants are preferred so as not to interfere with current flow within the organic electroluminescent element.

[0064] The organic solvent used in this invention may be a single solvent or a mixture of two or more solvents.

[0065] <Electron-accepting compounds> Electron-accepting compounds are preferably compounds that possess oxidizing power and the ability to accept one electron from the charge-transporting compound mentioned above. Specifically, electron-accepting compounds are preferably compounds with an electron affinity of 4.0 eV or more, and more preferably compounds with an electron affinity of 5.0 eV or more.

[0066] Electron-accepting compounds preferably contain elements with high electronegativity in order to act as electron-accepting reagents from charge-transporting compounds, and within the scope of the present invention, they contain fluorine atoms.

[0067] Examples of such electron-accepting compounds include one or more compounds selected from the group consisting of triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. More specifically, examples of electron-accepting compounds include onium salts with substituted organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. 2005 / 089024, International Publication No. 2017 / 164268); high-valence inorganic compounds such as iron(III) chloride (Japanese Patent Publication No. 11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene and aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Publication No. 2003-31365); fullerene derivatives; iodine; and sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions.

[0068] In the present invention, it is preferable that the electron-accepting compound has a crosslinkable substituent in order to prevent the electron-accepting compound from dissolving into the solvent of the composition coated on the upper layer of the functional film. In this case, it is preferable that the number of crosslinkable substituents in one molecule of the electron-accepting compound is two or more in order to prevent the electron-accepting compound alone from crosslinking and dissolving in a chain reaction.

[0069] The crosslinkable substituents are preferably substituents that undergo a chemical reaction upon external forces such as light or heat. Preferred examples of crosslinkable substituents are not limited to those listed below, but thermally crosslinkable substituents that undergo a crosslinking reaction upon heat are preferred. Examples include substituents containing a benzocyclobutene ring, a naphthocyclobutene ring, or an oxetane ring, as well as a vinyl group, an acrylic group, or a styryl group which may have an alkyl substituent. Note that any crosslinkable substituent may have substituents, with methyl groups and methoxy groups being preferred. As described above, it is preferable that the electron-accepting compound containing a fluorine atom is a compound having a crosslinkable substituent. More preferably, all electron-accepting compounds contained in functional composition B have a crosslinkable substituent.

[0070] (Content of electron-accepting compounds containing fluorine atoms) In the present invention, the electron-accepting compound containing fluorine atoms is preferably contained in 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, relative to the total functional composition B, from the viewpoint of improving conductivity. On the other hand, if too much of the electron-accepting compound containing fluorine is included, the surface energy of the functional film decreases, making it difficult to perform lamination coating. Therefore, it is preferably contained in 1% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.6% by mass or less, relative to the total functional composition B.

[0071] <Hole transport materials> The present invention may further include a hole transport material. Preferred embodiments of the hole transport material are described later in the section on the hole injection layer. The hole transport material content is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and even more preferably 1 to 5% by mass, relative to the total composition.

[0072] <Other ingredients> In the present invention, components other than electron-accepting compounds containing fluorine atoms, organic solvents, and hole transport materials may be included, such as antioxidants and additives that alter the physical properties of the composition. While these components may be important factors in determining the storage stability and ejection stability from the inkjet head of the composition, it is undesirable for them to have a significant impact on the inherent performance of the composition. Therefore, it is preferable that their amount be 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less of the total composition.

[0073] <Preparation of Composition> Functional composition B in the present invention can be prepared by mixing at least one electron-accepting compound containing a fluorine atom with an organic solvent and heating for a certain period of time to dissolve or disperse the mixture. In order to uniformly dissolve or disperse at least one electron-accepting compound containing a fluorine atom in the solvent, the heating temperature is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, for example, 100 to 115°C. The heating time is preferably 30 minutes or more, more preferably 45 minutes or more, and even more preferably 60 minutes or more, for example, 60 to 180 minutes.

[0074] The heated composition is filtered using a membrane filter, depth filter, or the like to remove coarse particles before use. Considering that the composition is dispensed from the nozzle of an inkjet head, the pore size of the filter is preferably 0.5 μm or less, more preferably 0.2 μm or less, and even more preferably 0.1 μm or less.

[0075] <Film formation by wet deposition method> Functional composition B of the present invention is suitably used for forming a functional film in the manufacture of an organic electroluminescent device. The configuration of the organic electroluminescent device is as described below.

[0076] The organic electroluminescent element in the present invention typically has light-emitting pixels on a substrate provided with electrodes, in minute regions partitioned by partitions called liquid-repellent partition layers (banks). The functional composition B of the present invention is extruded into these minute regions partitioned by partition layers, dried, and appropriately heated to form a functional film.

[0077] The ejection method involves ejecting droplets smaller than the micro-regions partitioned by the partition layers from a minute nozzle, and it is preferable to fill the micro-regions partitioned by the partition layers with the functional composition B of the present invention by ejecting multiple droplets. The ejection method is preferably an inkjet method.

[0078] In the wet film deposition method, a microscopic region partitioned by a bank is filled with a functional film-forming composition, and then the solvent is evaporated and dried by appropriate means to obtain a functional film. The means of evaporation and drying are not limited to the following, but include heating drying and vacuum drying. For example, vacuum drying involves placing a substrate coated with the composition in a metal or glass vacuum chamber that can be opened and closed, and evaporating the solvent by reducing the pressure of the atmosphere inside the chamber with a vacuum pump or the like. Vacuum pumps commonly used include rotary oil pumps, mechanical booster pumps, dry scroll pumps, dry roots pumps, turbomolecular pumps, and cryopumps.

[0079] The heating temperature for functional materials is usually 80°C or higher, preferably 100°C or higher, more preferably 150°C or higher, and more preferably 200°C or higher, and usually 300°C or lower, preferably 270°C or lower, and more preferably 240°C or lower. The heating time is usually 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more, and usually 120 minutes or less, preferably 90 minutes or less, and more preferably 60 minutes or less.

[0080] Heating can be carried out using a hot plate, oven, infrared irradiation, etc. In the case of infrared irradiation, which directly applies molecular vibrations, a heating time close to the lower limit above is sufficient. In the case of hot plate heating, where the substrate is in direct contact with the heat source or the heat source and substrate are placed very close together, a longer time is required than with infrared irradiation. In the case of oven heating, that is, heating with a gas inside the oven, usually air or an inert gas such as nitrogen or argon, it takes time for the temperature to rise, so a heating time close to the upper limit above is preferable. The heating time is adjusted as appropriate depending on the heating method.

[0081] It is important that this heating process is carried out under conditions that cause a crosslinking reaction between the crosslinking groups of the functional materials, such as the charge-transporting polymer compound and the low-molecular-weight compound, according to the present invention. For this reason, the heating temperature is preferably above the crosslinking initiation temperature of the crosslinking groups of the charge-transporting polymer compound, the low-molecular-weight compound, and, if present, the electron-accepting compound, according to the present invention.

[0082] In the composition of the present invention, the pin position of the composition on the bank side decreases during the drying process by volatilizing the solvent in the composition. However, if drying is too fast, there is not enough time to lower the pin position, making it difficult to form a flat film. Therefore, it is preferable that the time until the pressure reaches a level lower than the vapor pressure of the organic solvent with the lowest vapor pressure among the organic solvents contained in the composition of the present invention is 10 seconds or more, more preferably 20 seconds or more, and even more preferably 30 seconds or more. On the other hand, if the composition continues to come into contact with the bank side, a problem arises in which the material forming the bank gradually dissolves from the bank into the solvent of the composition. Therefore, it is preferable that the time until the pressure reaches a level lower than the vapor pressure of the organic solvent with the lowest vapor pressure among the organic solvents contained in the composition of the present invention is 600 seconds or less, more preferably 500 seconds or less, and even more preferably 400 seconds or less.

[0083] <Functional membrane> The functional film of the present invention is a film obtained by volatilizing the organic solvent component of functional composition B through drying. To give the functional film the function of transporting holes, it is preferable that the functional film contains at least one electron-accepting compound containing fluorine, in addition to at least one hole transport material. The content of the electron-accepting compound containing fluorine in the functional film is usually 1% by mass or more, preferably 5% by mass or more, and more preferably 10% by mass or more. It is also usually less than 50% by mass, preferably less than 40% by mass, and more preferably less than 30% by mass. By having the electron-accepting compound within the above range, an appropriate hole transport function can be achieved. Furthermore, the functional film may contain trace amounts of additives, residual solvents, and impurities, preferably less than 1% by mass, more preferably less than 0.1% by mass, and even more preferably less than 0.05% by mass.

[0084] [Layer structure and formation method of organic electroluminescent devices] The present invention also relates to an organic electroluminescent element manufactured by the manufacturing method described above. Preferred examples of the layer configuration and method for forming the organic electroluminescent element of the present invention will be described with reference to Figure 1.

[0085] Figure 1 is a schematic cross-sectional diagram showing an example of the structure of the organic electroluminescent element 10 of the present invention. In Figure 1, 1 represents the substrate, 2 the anode, 3 the hole injection layer, 4 the hole transport layer, 5 the light-emitting layer, 6 the hole blocking layer, 7 the electron transport layer, 8 the electron injection layer, and 9 the cathode.

[0086] The organic electroluminescent device of the present invention has an anode, a light-emitting layer, and a cathode as essential constituent layers, but may optionally have other functional layers between the anode 2 and the light-emitting layer 5 and between the cathode 9 and the light-emitting layer 5, as shown in Figure 1.

[0087] [substrate] Substrate 1 serves as a support for the organic electroluminescent element. Substrate 1 can be a plate of quartz or glass, a metal plate or foil, a plastic film or sheet, etc. Glass plates, or transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, or polysulfone are particularly preferred. When using a synthetic resin substrate, it is preferable to pay attention to its gas barrier properties. A high gas barrier property of the substrate is desirable because it reduces the likelihood of degradation of the organic electroluminescent element due to outside air passing through the substrate. Therefore, one preferred method is to ensure gas barrier properties by providing a dense silicon oxide film or the like on at least one side of the synthetic resin substrate.

[0088] [anode] Anode 2 is an electrode that plays the role of injecting holes into the layer on the light-emitting layer 5 side. Anode 2 is typically composed of metals such as aluminum, gold, silver, nickel, palladium, and platinum, or alloys of these metals with indium, copper, tellurium, palladium, and aluminum, metal oxides such as indium and / or tin oxide, metal halides such as copper iodide, carbon black, or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline.

[0089] The formation of anode 2 is usually carried out by methods such as sputtering or vacuum deposition. When forming anode 2 using metal nanoparticles such as silver, nanoparticles such as copper iodide, carbon black, conductive metal oxide nanoparticles, conductive polymer fine powder, etc., the anode 2 can also be formed by dispersing these nanoparticles in a suitable binder resin solution and coating it onto substrate 1. In the case of conductive polymers, a thin film can also be formed directly on the substrate 1 by electrolytic polymerization. A conductive polymer can also be applied to substrate 1 to form anode 2 (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0090] Anode 2 is usually a single-layer structure, but it can also be a multilayer structure consisting of multiple materials if desired.

[0091] The thickness of anode 2 can be appropriately selected depending on the required transparency. If transparency is required, the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness of anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably around 500 nm or less. If opacity is acceptable, the thickness of anode 2 is arbitrary. A substrate 1 that also functions as anode 2 may be used. It is also possible to laminate different conductive materials on top of the above anode 2.

[0092] To remove impurities adhering to anode 2 and adjust the ionization potential to improve hole injection performance, it is preferable to treat the surface of anode 2 with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma.

[0093] [Bank formation] The present invention relates to a method for manufacturing an organic electroluminescent element, which includes the steps of applying a liquid-repellent photosensitive composition A (hereinafter also referred to as "liquid-repellent resist") to a substrate having a patterned electrode layer, and forming a patterned structure by photolithography. The patterned electrode layer is preferably a glass substrate having a conductive electrode pattern. Furthermore, it is preferable that the structure has a plurality of micro-region openings (banks). Methods for applying a liquid-repellent resist include using a coating device such as a roll coater, reverse coater, bar coater, spinner (rotary coating device), die coater, or inkjet on the substrate. If necessary, the solvent is removed by drying to form a liquid-repellent resist layer.

[0094] Next, in the exposure process, a mask is used to irradiate the liquid-repellent resist with active energy rays such as ultraviolet light or excimer laser light, partially exposing the liquid-repellent resist according to the pattern of the pixel partitioning layer. For exposure by ultraviolet irradiation, light sources that emit ultraviolet light such as high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, and carbon arc lamps can be used. The exposure amount also varies depending on the composition of the photosensitive resin composition, but for example, it is 10 to 400 mJ / cm². 2 A certain degree is desirable. In the case of a negative-type liquid-repellent resist, by using a mask in which light-shielding areas of 10 to 300 μm are arranged in a linear or rectangular pattern, a pattern having multiple openings in minute regions of 10 to 300 μm can be created.

[0095] Next, in the development process, a pattern is formed by developing the liquid-repellent resist that has been exposed according to the pattern of the pixel partitioning layer. The development method is not particularly limited, and methods such as immersion or spraying can be used. Specific examples of developers include organic ones such as dimethylbenzylamine, monoethanolamine, diethanolamine, and triethanolamine, as well as aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, and quaternary ammonium salts. In addition, defoamers and surfactants may be added to the developer.

[0096] Subsequently, the pixel separation layer is obtained by post-baking and heat-curing the developed liquid-repellent resist. Post-baking is preferably performed at 150-250°C for 15-60 minutes.

[0097] After pattern formation, the substrate surface is preferably treated using external energy to remove residues from resist coating or photolithography. Preferred external energy sources include ultraviolet (UV) / ozone treatment, oxygen plasma, and plasma etching.

[0098] [Hole injection layer] The hole injection layer 3 is a layer that transports holes from the anode 2 to the light-emitting layer 5. When the hole injection layer 3 is provided, it is usually formed on the anode 2.

[0099] The method for forming the hole injection layer 3 can be either vacuum deposition or wet deposition, and there are no particular restrictions. However, from the viewpoint of reducing dark spots, it is preferable to form the hole injection layer 3 by wet deposition. The thickness of the hole injection layer 3 is typically 5 nm or more, preferably 10 nm or more, and typically 1000 nm or less, preferably 500 nm or less.

[0100] <Hole transport materials> Compositions for forming hole injection layers typically contain a hole transport material and a solvent as constituent materials of the hole injection layer 3.

[0101] The hole transport material is a compound that has hole transport properties and is typically used in the hole injection layer 3 of an organic electroluminescent device. It may be a polymer or other high-molecular-weight compound, or a monomer or other low-molecular-weight compound, but it is preferably a polymer. When the scope of application of the present invention is applied to the hole injection layer 3, the composition is characterized by containing at least one hole-transporting polymer material having a crosslinking group with a weight-average molecular weight of 10,000 or more, at least one hole-transporting low-molecular-weight material having a crosslinking group with a molecular weight of 5,000 or less, and at least one aromatic organic solvent.

[0102] As hole transport materials, compounds having an ionization potential of 4.5 eV to 6.0 eV are preferred from the viewpoint of a charge injection barrier from anode 2 to hole injection layer 3. Examples of hole transport materials include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by fluorene groups, hydrazone derivatives, silazane derivatives, silanamin derivatives, phosphatamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon, and the like.

[0103] In the present invention, a derivative, for example, in the case of an aromatic amine derivative, includes the aromatic amine itself and compounds having an aromatic amine as the main skeleton, and may be a polymer or a monomer.

[0104] The hole transport material used as the material for the hole injection layer 3 may contain one of these compounds alone, or two or more. When two or more hole transport materials are included, the combination is arbitrary, but it is preferable to use one or more aromatic tertiary amine polymer compounds in combination with one or more other hole transport materials.

[0105] As hole transport materials, aromatic amine compounds are preferred among those exemplified above in terms of amorphous nature and visible light transmittance, and aromatic tertiary amine compounds are particularly preferred. Aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure, and also include compounds having groups derived from aromatic tertiary amines.

[0106] The type of aromatic tertiary amine compound is not particularly limited, but polymer compounds (polymerized compounds with repeating units) with a weight-average molecular weight of 1,000 or more and 1,000,000 or less are more preferred from the viewpoint of uniform luminescence due to the surface smoothing effect. Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds having repeating units represented by the following formula (1) or formula (11).

[0107] [ka]

[0108] (In formula (1), Ar 3 This represents an aromatic hydrocarbon group or an aromatic heterocyclic group, which may have substituents. Ar 4 This represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group, which may have substituents, or a divalent group formed by the direct or mediated linkage of multiple such aromatic hydrocarbon and aromatic heterocyclic groups.

[0109] In formula (1) above, when an aromatic hydrocarbon group and an aromatic heterocyclic group are linked together via a linking group, the linking group is a divalent linking group, and examples include a group formed by linking 1 to 30 groups, preferably 1 to 5, and more preferably 1 to 3, selected from -O- groups, -C(=O)- groups, and (may have substituents) -CH2- groups in any order. Among the linking groups, Ar in formula (1) is superior in that it is excellent at hole injection into the light-emitting layer. 4 However, it is preferable that the aromatic hydrocarbon group or aromatic heterocyclic group is linked together via a linking group represented by the following formula (2).

[0110] [ka]

[0111] (In formula (2), y1 represents an integer between 1 and 10. R8 and R 9 Each of these independently represents an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group, which may have a hydrogen atom or a substituent. R 8 , R 9 If multiple instances exist, they may be the same or different.

[0112] [ka]

[0113] In equation (11) above, x1, x2, x3, x4, x5, and x6 each independently represent a non-negative integer, provided that x3 + x4 ≥ 1. 11 Ar 12 Ar 14 Each of these independently represents a divalent aromatic ring group having 30 or fewer carbon atoms, which may have substituents. 13 Q represents a divalent aromatic ring group having 30 or fewer carbon atoms, which may have substituents, or a divalent group represented by the following formula (12). 11 Q 12 Each of these independently represents an oxygen atom, a sulfur atom, or a hydrocarbon chain having 6 or fewer carbon atoms, which may have substituents. 1 ~S 4 Each of these is independently represented by the group shown in formula (13) below. In this context, "aromatic ring group" refers to aromatic hydrocarbon groups and aromatic heterocyclic groups.

[0114] Ar 11 Ar 12 Ar 14Examples of aromatic ring groups include monocyclic rings, 2-6 fused rings, or groups in which two or more of these aromatic rings are linked. Specific examples of monocyclic or 2-6 fused ring aromatic ring groups include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, fluorene rings, biphenyl groups, terphenyl groups, quaterphenyl groups, furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, and pyrrolymidazole rings. Examples of divalent groups derived from benzene rings, pyrrolopyrazole rings, pyrrolopyrrole rings, thienopyrrole rings, thienothiophene rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, cinolinoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, or azulene rings. Among these, divalent groups derived from benzene rings, naphthalene rings, fluorene rings, pyridine rings, or carbazole rings, or biphenyl groups, are preferred because they efficiently delocalize negative charges and have excellent stability and heat resistance. Ar 13 Examples of aromatic ring groups include Ar 11 Ar 12 Ar 14 This is the same as in the previous case.

[0115] [ka]

[0116] In the above equation (12), R 11 R represents an alkyl group, an aromatic ring group, or a trivalent group consisting of an alkyl group with 40 or fewer carbon atoms and an aromatic ring group, and these may have substituents. 12 represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group with 40 or fewer carbon atoms and an aromatic ring group, and these may have substituents. 31x represents a monovalent aromatic ring group or a monovalent bridging group, and these groups may have substituents. x7 represents 1 to 4. If x7 is 2 or more, multiple R 12 They may be the same or different, and multiple Ar 31 These may be the same or different. An asterisk (*) indicates a bond with the nitrogen atom in equation (11).

[0117] R 11 The aromatic ring group is preferably a single aromatic ring group having 3 to 30 carbon atoms, either a monocyclic or fused ring, or a group in which 2 to 6 such rings are linked together. Specific examples include trivalent groups derived from benzene rings, fluorene rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and groups in which 2 to 6 of these rings are linked together. R 11 The alkyl group is preferably a linear, branched, or ring-containing alkyl group having 1 to 12 carbon atoms. Specific examples include groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, and octane. R 11 Preferably, the group consisting of an alkyl group having 40 or fewer carbon atoms and an aromatic ring group is a group in which a linear, branched, or ring-containing alkyl group having 1 to 12 carbon atoms is linked to one or two to six aromatic ring groups that are monocyclic or fused rings having 3 to 30 carbon atoms.

[0118] R 12 Specific examples of aromatic ring groups include benzene rings, fluorene rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and divalent groups derived from linked rings with 30 or fewer carbon atoms. R 12 Specific examples of alkyl groups include divalent groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, and octane.

[0119] Ar 31Specific examples of aromatic ring groups include benzene rings, fluorene rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and monovalent groups derived from linked rings with 30 or fewer carbon atoms.

[0120] Examples of preferred structures of formula (12) include the following structure, R 11 In the following substructure, the benzene ring or fluorene ring in the main chain may have further substituents.

[0121] [ka]

[0122] Ar 31 Examples of crosslinking groups include groups derived from benzocyclobutene rings, naphthocyclobutene rings, or oxetane rings, vinyl groups, acrylic groups, etc. Due to the stability of the compound, groups derived from benzocyclobutene rings or naphthocyclobutene rings are preferred.

[0123] [ka]

[0124] In equation (13) above, x and y represent integers greater than or equal to 0. 21 Ar 23 Each of these independently represents a divalent aromatic ring group, and these groups may have substituents. 22 R represents a monovalent aromatic ring group which may have substituents, 13 represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group and an aromatic ring group, which may have substituents. 32 represents a monovalent aromatic ring group or a monovalent bridging group, and these groups may have substituents. An asterisk (*) indicates a bond with the nitrogen atom in formula (11).

[0125] Ar 21 Ar 23 Examples of aromatic ring groups include Ar 11 Ar12 Ar 14 This is the same as in the previous case.

[0126] Ar 22 Ar 32 Examples of aromatic ring groups include monocyclic rings, 2-6 fused rings, or groups in which two or more of these aromatic rings are linked. Specific examples include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, fluorene rings, biphenyl groups, terphenyl groups, quaterphenyl groups, furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, pyrroloimidazole rings, pyrrolopy Examples include monovalent groups derived from razole rings, pyrrolopyrrole rings, thienopyrrole rings, thienothiophene rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, cinolinic rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, or azulene rings. Among these, monovalent groups derived from benzene rings, naphthalene rings, fluorene rings, pyridine rings, or carbazole rings, or biphenyl groups, are preferred because they efficiently delocalize negative charges and have excellent stability and heat resistance.

[0127] R 13 Examples of alkyl groups or aromatic ring groups include R 12 It is similar to that.

[0128] Ar 32 The crosslinking group is not particularly limited, but preferred examples include groups derived from benzocyclobutene rings, naphthocyclobutene rings or oxetane rings, vinyl groups, acrylic groups, and the like.

[0129] The above Ar 11 ~Ar 14 , R 11~R 13 Ar 21 ~Ar 23 Ar 31 ~Ar 32 Q 11 Q 12 Each of these may have further substituents, as long as it does not contradict the spirit of the present invention. The molecular weight of the substituent is preferably 400 or less, and more preferably 250 or less. The type of substituent is not particularly limited, but examples include one or more types selected from the substituent group W below.

[0130] [Substituent group W] Alkyl groups having 1 or more carbon atoms, preferably 10 or less, and more preferably 8 or less, such as methyl and ethyl groups; alkenyl groups having 2 or more carbon atoms, preferably 11 or less, and more preferably 5 or less, such as vinyl groups; alkynyl groups having 2 or more carbon atoms, preferably 11 or less, and more preferably 5 or less, such as ethynyl groups; alkoxy groups having 1 or more carbon atoms, preferably 10 or less, and more preferably 6 or less, such as methoxy and ethoxy groups; phenoxy, naphthoxy, pyridyloxy groups, etc. having 4 or more carbon atoms, preferably 5 or more, preferably 25 or less, and more preferably 14 or fewer aryloxy groups; methoxycarbonyl groups, ethoxycarbonyl groups, etc., with 2 or more carbon atoms, preferably 11 or fewer, more preferably 7 or fewer; dialkylamino groups, etc., with 2 or more carbon atoms, preferably 20 or fewer, more preferably 12 or fewer; diarylamino groups, etc., with 10 or more carbon atoms, preferably 12 or more, preferably 30 or fewer, more preferably 22 or fewer; phenylmethylamino groups, etc., with 6 or more carbon atoms. , more preferably 7 or more, preferably 25 or less, and more preferably 17 or less arylalkylamino groups; acetyl groups, benzoyl groups, etc., with 2 or more carbon atoms, preferably 10 or less, and more preferably 7 or less acyl groups; halogen atoms such as fluorine atoms and chlorine atoms; haloalkyl groups such as trifluoromethyl groups, with 1 or more carbon atoms, preferably 8 or less, and more preferably 4 or less haloalkyl groups; methylthio groups, ethylthio groups, etc., with 1 or more carbon atoms, preferably 10 or less, and more preferably 6 or less alkylthio groups; phenylthio groups, naphthylthio groups, pyridylthio groups, etc. arylthio groups having 4 or more carbon atoms, preferably 5 or more, preferably 25 or less, and more preferably 14 or less; silyl groups having 2 or more carbon atoms, preferably 3 or more, preferably 33 or less, and more preferably 26 or less, such as trimethylsilyl group and triphenylsilyl group; siloxy groups having 2 or more carbon atoms, preferably 3 or more, preferably 33 or less, and more preferably 26 or less, such as trimethylsiloxy group and triphenylsiloxy group; cyano groups; aromatic hydrocarbon groups having 6 or more carbon atoms, preferably 30 or less, and more preferably 18 or less, such as phenyl group and naphthyl group;Aromatic heterocyclic groups such as thienyl groups and pyridyl groups, having 3 or more carbon atoms, preferably 4 or more, preferably 28 or fewer, and more preferably 17 or fewer.

[0131] Of the substituent group W described above, alkyl groups or alkoxy groups are preferred from the viewpoint of improving solubility, and aromatic hydrocarbon groups or aromatic heterocyclic groups are preferred from the viewpoint of charge transport and stability.

[0132] In particular, among polymer compounds having repeating units represented by formula (11), polymer compounds having repeating units represented by formula (14) below are preferred because they exhibit very high hole injection and transport properties.

[0133] [ka]

[0134] In the above equation (14), R 21 ~R 25 Each of these independently represents an arbitrary substituent. 21 ~R 25 Specific examples of substituents are the same as those listed in [substituent group W] above. s and t each independently represent integers between 0 and 5, inclusive. u, v, and w each independently represent integers between 0 and 4, inclusive.

[0135] Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds containing repeating units represented by the following formulas (15) and / or (16).

[0136] [ka]

[0137] In equations (15) and (16) above, Ar 45 Ar 47 and Ar 48Each independently represents a monovalent aromatic hydrocarbon group which may have a substituent or a monovalent aromatic heterocyclic group which may have a substituent. Ar 44 and Ar 46 Each independently represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent. R 41 ~R 43 Each independently represents a hydrogen atom or an arbitrary substituent.

[0138] Ar 45 、Ar 47 and Ar 48 Specific examples, preferred examples, examples of substituents which may be possessed and preferred examples of substituents of Ar 22 are the same as those of Ar 44 and Ar 46 Specific examples, preferred examples, examples of substituents which may be possessed and preferred examples of substituents of Ar 11 、Ar 12 and Ar 14 are the same as those of Ar 41 ~R 43 Preferably, it is a hydrogen atom or a substituent described in the aforementioned [substituent group W], and more preferably, it is a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group or an aromatic heterocyclic group.

[0139] Hereinafter, preferred specific examples of the repeating units represented by formula (15) and formula (16) applicable in the present invention are given, but the present invention is not limited thereto.

[0140]

Chemical formula

[0141] <Electron-accepting compound> The composition for forming a hole injection layer preferably contains an electron-accepting compound as a constituent material of the hole injection layer 3.

[0142] Electron-accepting compounds are preferably compounds that possess oxidizing power and the ability to accept one electron from the hole transport material mentioned above. Specifically, electron-accepting compounds are preferably those with an electron affinity of 4.0 eV or higher, and more preferably those with an electron affinity of 5.0 eV or higher.

[0143] Examples of such electron-accepting compounds include one or more compounds selected from the group consisting of triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. More specifically, examples of electron-accepting compounds include onium salts with substituted organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate (International Publication No. 2005 / 089024, International Publication No. 2017 / 164268); high-valence inorganic compounds such as iron(III) chloride (Japanese Patent Publication No. 11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene and aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Publication No. 2003-31365); fullerene derivatives; iodine; and sulfonate ions such as polystyrene sulfonate ions, alkylbenzene sulfonate ions, and camphor sulfonate ions.

[0144] The electron-accepting compound can improve the conductivity of the hole injection layer 3 by oxidizing the hole transport material.

[0145] <Other constituent materials> As long as the effects of the present invention are not significantly impaired, the material of the hole injection layer 3 may also contain other components in addition to the hole transport material and electron-accepting compound described above.

[0146] <Solvent> It is preferable that at least one of the solvents in the hole injection layer formation composition used in the wet film deposition method is a compound capable of dissolving the constituent materials of the hole injection layer 3 described above.

[0147] Examples of solvents include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

[0148] Examples of ether-based solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, 3-phenoxytoluene, diphenyl ether, and dibenzyl ether.

[0149] Examples of ester solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, isobutyl benzoate, pentyl benzoate, isopentyl benzoate, methyl toluate, ethyl toluate, methyl anisate, ethyl anisate, dimethyl phthalate, diethyl phthalate, phenoxyethyl acetate, and phenoxyethyl butyrate.

[0150] Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, trimethylbenzene, tetramethylbenzene, diisopropylbenzene, triisopropylbenzene, methylnaphthalene, ethylnaphthalene, isopropylnaphthalene, diisopropylnaphthalene, ethylbiphenyl, isopropylbiphenyl, butylbiphenyl, diisopropylbiphenyl, triisopropylbiphenyl, tetralin, 1,1-diphenylethane, 1,1-diphenylpropane, 1,1-diphenylbutane, 1,1-diphenylpentane, and 1,1-diphenylhexane.

[0151] Examples of amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide. Other substances such as dimethyl sulfoxide can also be used. Among these, aromatic esters and aromatic ethers are particularly preferred.

[0152] These solvents may be used individually, or two or more may be used in any combination and ratio.

[0153] The concentration of the hole transport material in the hole injection layer forming composition is arbitrary as long as it does not significantly impair the effects of the present invention. From the viewpoint of uniformity of film thickness, the concentration of the hole transport material in the hole injection layer forming composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more. The concentration of the hole transport material in the hole injection layer forming composition is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. This concentration is preferable in that it is less likely to cause unevenness in film thickness. This concentration is also preferable in that it is less likely to cause defects in the formed hole injection layer.

[0154] <Formation of hole injection layer by wet deposition method> When forming a hole injection layer 3 by a wet deposition method, a composition for film formation (composition for forming the hole injection layer) is usually prepared by mixing the materials constituting the hole injection layer 3 with a suitable solvent (solvent for the hole injection layer). This composition for forming the hole injection layer 3 is then applied to the layer corresponding to the layer below the hole injection layer (usually the anode 2) using an appropriate method, deposited, and dried to form the hole injection layer 3.

[0155] [Hole transport layer] The hole transport layer 4 is a layer that transports holes from the anode 2 to the light-emitting layer 5. The hole transport layer 4 is not an essential layer for the organic electroluminescent element of the present invention, but when the hole transport layer 4 is provided, it is usually formed on the hole injection layer 3 if there is a hole injection layer 3, and on the anode 2 if there is no hole injection layer 3.

[0156] The method for forming the hole transport layer 4 can be either vacuum deposition or wet deposition, and there are no particular restrictions. However, from the viewpoint of reducing dark spots, it is preferable to form the hole transport layer 4 by wet deposition.

[0157] The material forming the hole transport layer 4 is preferably a material that has high hole transport properties and can efficiently transport the injected holes. For this reason, the material forming the hole transport layer 4 is preferably one that has a low ionization potential, high transparency to visible light, high hole mobility, excellent stability, and is less likely to generate trapping impurities during manufacturing or use. In most cases, the hole transport layer 4 is in contact with the light-emitting layer 5, so it is preferable that it does not quench the light emission from the light-emitting layer 5 or form an excyplex with the light-emitting layer 5, thereby reducing efficiency.

[0158] The material for the hole transport layer 4 can be any material that has been conventionally used as a constituent material for the hole transport layer 4. Examples of materials for the hole transport layer 4 include arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatic derivatives, and metal complexes.

[0159] Examples of materials for the hole transport layer 4 include polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ethersulfone derivatives containing tetraphenylbenzidine, polyarylenevinylene derivatives, polysiloxane derivatives, polythiophene derivatives, and poly(p-phenylenevinylene) derivatives. These may be alternating copolymers, random polymers, block polymers, or graft copolymers. They may also be polymers with branched main chains and three or more terminal ends, or so-called dendrimers.

[0160] In particular, polyarylamine derivatives and polyarylene derivatives are preferred as the material for the hole transport layer 4. Specific examples of polyarylamine derivatives and polyarylene derivatives include those described in Japanese Patent Publication No. 2008-98619. As the polyarylamine derivative, it is preferable to use the aforementioned aromatic tertiary amine polymer compound.

[0161] When forming the hole transport layer 4 by a wet film deposition method, the hole transport layer forming composition is prepared in the same manner as for forming the hole injection layer 3, followed by wet film deposition and drying. The hole transport layer formation composition contains a solvent in addition to the hole transport material described above. The solvent used is the same as that used in the hole injection layer formation composition. The film formation conditions, drying conditions, etc., are also the same as those for the formation of hole injection layer 3. If the hole transport layer forming composition is the composition of the present invention, the solvent is the first solvent and the second solvent of the present invention. When forming the hole transport layer 4 by vacuum deposition, the film formation conditions are the same as those for forming the hole injection layer 3.

[0162] The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 200 nm or less, taking into consideration factors such as the penetration of low molecular weight material in the light-emitting layer and the swelling of the hole transport material.

[0163] [Luminous layer] The light-emitting layer 5 is the main light-emitting layer, excited by the recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes under an applied electric field. The light-emitting layer 5 is usually formed on top of the hole transport layer 4 if one is present, on top of the hole injection layer 3 if one is present but one is not, and on top of the anode 2 if neither the hole transport layer 4 nor the hole injection layer 3 is present.

[0164] <Materials for the luminescent layer> Materials for light-emitting layers typically include a light-emitting material and a host charge transport material.

[0165] <Luminescent material> As the luminescent material, any known material that is usually used as a luminescent material for an organic electroluminescent device can be applied, and there is no particular limitation. A substance that emits light at a desired emission wavelength and has good luminous efficiency may be used. The luminescent material may be a fluorescent luminescent material or a phosphorescent luminescent material, but from the viewpoint of internal quantum efficiency, it is preferably a phosphorescent luminescent material. More preferably, the red luminescent material and the green luminescent material are phosphorescent luminescent materials, and the blue luminescent material is a fluorescent luminescent material.

[0166] When the composition of the present invention is a composition for forming a light-emitting layer, it is preferable to use the following phosphorescent luminescent material, fluorescent luminescent material, and charge transport material.

[0167] <Phosphorescent luminescent material> A phosphorescent luminescent material refers to a material that emits light from an excited triplet state. For example, metal complex compounds having Ir, Pt, Eu, etc. are representative examples, and as the structure of the material, those containing a metal complex are preferable.

[0168] Among metal complexes, as phosphorescent luminescent organometallic complexes that emit light via a triplet state, Werner-type complexes or organometallic complex compounds containing a metal selected from Groups 7 to 11 of the long-period periodic table (hereinafter, unless otherwise specified, the "periodic table" refers to the long-period periodic table) as a central metal can be mentioned. Examples of such phosphorescent luminescent materials include those described in International Publication No. 2014 / 024889, International Publication No. 2015-087961, International Publication No. 2016 / 194784, and JP-A No. 2014-074000. Preferably, a compound represented by the following formula (201) or a compound represented by the following formula (205) is preferable, and more preferably a compound represented by the following formula (201).

[0169]

Chemical formula

[0170] In formula (201), ring A1 represents an aromatic hydrocarbon ring structure which may have substituents or an aromatic heterocyclic ring structure which may have substituents. Ring A2 represents an aromatic heterocyclic ring structure which may have substituents. R 101 and R 102 each independently have a structure represented by formula (202), and "*" represents the bonding position with ring A1 or ring A2. R 101 and R 102 may be the same or different, and when there are a plurality of R 101 and R 102 respectively, they may be the same or different.

[0171] Ar 201 and Ar 203 each independently represent an aromatic hydrocarbon ring structure which may have substituents or an aromatic heterocyclic ring structure which may have substituents. Ar 202 represents an aromatic hydrocarbon ring structure which may have substituents, an aromatic heterocyclic ring structure which may have substituents, or an aliphatic hydrocarbon structure which may have substituents. The substituents bonded to ring A1, the substituents bonded to ring A2, or the substituents bonded to ring A1 and the substituents bonded to ring A2 may bond to each other to form a ring.

[0172] B 201 -L 200 -B 202 represents an anionic bidentate ligand. B 201 and B 202 each independently represent a carbon atom, an oxygen atom or a nitrogen atom, and these atoms may be atoms constituting a ring. L 200 represents a single bond or an atomic group that forms a bidentate ligand together with B 201 and B 202 . When there are a plurality of B 201 -L 200 -B 202 , they may be the same or different.

[0173] In addition, in equations (201) and (202), i1 and i2 each independently represent integers between 0 and 12 (inclusive). i3 is Ar 202 Represents a non-negative integer with an upper limit of the number that can be substituted for, i4 is Ar 201 Represents a non-negative integer with an upper limit of the number that can be substituted for, k1 and k2 each independently represent non-negative integers up to the number of numbers that can be permuted in rings A1 and A2, respectively. z represents an integer between 1 and 3.

[0174] (substituent) Unless otherwise specified, the substituent is preferably a group selected from the following substituent group S.

[0175] <Substituent group S> Alkyl alkyl groups, preferably C1 to C20 alkyl groups, more preferably C1 to C12 alkyl groups, even more preferably C1 to C8 alkyl groups, and particularly preferably C1 to C6 alkyl groups. • Alkoxy groups, preferably alkoxy groups having 1 to 20 carbon atoms, more preferably alkoxy groups having 1 to 12 carbon atoms, and even more preferably alkoxy groups having 1 to 6 carbon atoms. • An aryloxy group, preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, even more preferably an aryloxy group having 6 to 12 carbon atoms, and particularly preferably an aryloxy group having 6 carbon atoms. A heteroaryloxy group, preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms. • Alkylamino group, preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms. • An arylamino group, preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms. Aralkyl groups, preferably aralkyl groups having 7 to 40 carbon atoms, more preferably aralkyl groups having 7 to 18 carbon atoms, and even more preferably aralkyl groups having 7 to 12 carbon atoms. • Heteroaralkyl group, preferably a heteroaralkyl group having 7 to 40 carbon atoms, more preferably a heteroaralkyl group having 7 to 18 carbon atoms. Alkenyl groups, preferably alkenyl groups having 2 to 20 carbon atoms, more preferably alkenyl groups having 2 to 12 carbon atoms, even more preferably alkenyl groups having 2 to 8 carbon atoms, and particularly preferably alkenyl groups having 2 to 6 carbon atoms. • Alkynyl group, preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms. • An aryl group, preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, even more preferably an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 14 carbon atoms. Heteroaryl groups, preferably heteroaryl groups having 3 to 30 carbon atoms, more preferably heteroaryl groups having 3 to 24 carbon atoms, even more preferably heteroaryl groups having 3 to 18 carbon atoms, and particularly preferably heteroaryl groups having 3 to 14 carbon atoms. • Alkylsilyl group, preferably an alkylsilyl group having 1 to 20 carbon atoms in the alkyl group, more preferably an alkylsilyl group having 1 to 12 carbon atoms in the alkyl group. • An arylsilyl group, preferably an arylsilyl group having 6 to 20 carbon atoms in the aryl group, more preferably an arylsilyl group having 6 to 14 carbon atoms in the aryl group. • Alkylcarbonyl group, preferably an alkylcarbonyl group having 2 to 20 carbon atoms. • Arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms.

[0176] The above groups may have one or more hydrogen atoms replaced by fluorine atoms, or one or more hydrogen atoms replaced by deuterium atoms. Unless otherwise specified, aryls are aromatic hydrocarbon rings, and heteroaryls are aromatic heterocycles. Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF5.

[0177] Of the above substituent group S, preferably are alkyl groups, alkoxy groups, aryloxy groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, alkylsilyl groups, arylsilyl groups, and groups in which one or more hydrogen atoms of these groups are replaced by fluorine atoms, fluorine atoms, cyano groups, or -SF5. More preferably alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, and groups in which one or more hydrogen atoms of these groups are replaced by fluorine atoms, fluorine atoms, cyano groups, or -SF5. More preferably, alkyl groups, alkoxy groups, aryloxy groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, alkylsilyl groups, and arylsilyl groups. Particularly preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, and heteroaryl groups. Most preferably, the group is an alkyl group, an arylamino group, an aralkyl group, an aryl group, or a heteroaryl group.

[0178] These substituent groups S may further contain substituents selected from substituent group S. The preferred groups, more preferred groups, even more preferred groups, particularly preferred groups, and most preferred groups of the substituents that may be present are the same as the preferred groups in substituent group S.

[0179] (Ring A1) Ring A1 represents an aromatic hydrocarbon ring structure or an aromatic heterocyclic structure that may have substituents.

[0180] The aromatic hydrocarbon ring is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, benzene rings, naphthalene rings, anthracene rings, triphenylyl rings, acenaphthene rings, fluorantene rings, and fluorene rings are preferred.

[0181] As the aromatic heterocyclic ring, an aromatic heterocyclic ring having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom, or a sulfur atom as a hetero atom is preferable. More preferably, it is a furan ring, a benzofuran ring, a thiophene ring, or a benzothiophene ring. More preferably, ring A1 is a benzene ring, a naphthalene ring, or a fluorene ring, particularly preferably a benzene ring or a fluorene ring, and most preferably a benzene ring.

[0182] (Ring A2) Ring A2 represents an aromatic heterocyclic ring structure which may have a substituent. As the aromatic heterocyclic ring, preferably it is an aromatic heterocyclic ring having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom, or a sulfur atom as a hetero atom. Specifically, a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, an oxazole ring, a thiazole ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, a phenanthridine ring can be mentioned. Preferably, a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, a benzothiazole ring, a benzoxazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, more preferably a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, and most preferably a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, a quinoxaline ring, a quinazoline ring.

[0183] (Combination of ring A1 and ring A2) As a preferable combination of ring A1 and ring A2, when expressed as (ring A1 - ring A2), it is (benzene ring - pyridine ring), (benzene ring - quinoline ring), (benzene ring - quinoxaline ring), (benzene ring - quinazoline ring), (benzene ring - benzothiazole ring), (benzene ring - imidazole ring), (benzene ring - pyrrole ring), (benzene ring - diazole ring), and (benzene ring - thiophene ring).

[0184] (Substituents of ring A1 and ring A2) The substituents that rings A1 and A2 may have can be arbitrarily selected, but preferably one or more substituents selected from the substituent group S.

[0185] (Ar 201 Ar 202 Ar 203 ) Ar 201 Ar 203 Each of these independently represents an aromatic hydrocarbon ring structure that may have substituents, or an aromatic heterocyclic ring structure that may have substituents. Ar 202 This represents an optionally substituted aromatic hydrocarbon ring structure, an optionally substituted aromatic heterocyclic structure, or an optionally substituted aliphatic hydrocarbon structure.

[0186] Ar 201 Ar 202 Ar 203 If any of the elements is an aromatic hydrocarbon ring structure which may have substituents, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, a benzene ring, naphthalene ring, anthracene ring, triphenylyl ring, acenaphthene ring, fluorantene ring, or fluorene ring is preferred, more preferably a benzene ring, naphthalene ring, or fluorene ring, and most preferably a benzene ring.

[0187] Ar 201 Ar 202 If any of the elements is a benzene ring which may have substituents, it is preferable that at least one benzene ring is bonded to an adjacent structure at the ortho or meta position, and more preferably that at least one benzene ring is bonded to an adjacent structure at the meta position.

[0188] Ar 201 Ar 202 Ar 203 If either of the elements is a fluorene ring which may have substituents, it is preferable that the 9th and 9' positions of the fluorene ring have substituents or are bonded to adjacent structures.

[0189] Ar 201 Ar 202 Ar 203 In the case of an aromatic heterocyclic structure in which any of the elements may have substituents, the aromatic heterocyclic structure is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms and containing a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom. Specifically, examples include pyridine rings, pyrimidine rings, pyrazine rings, triazine rings, imidazole rings, oxazole rings, thiazole rings, benzothiazole rings, benzoxazole rings, benzimidazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, quinazoline rings, naphthyridine rings, phenantholidine rings, carbazole rings, dibenzofuran rings, and dibenzothiophene rings, and preferably pyridine rings, pyrimidine rings, triazine rings, carbazole rings, dibenzofuran rings, and dibenzothiophene rings.

[0190] Ar 201 Ar 202 Ar 203 If either of the elements is a carbazole ring which may have substituents, it is preferable that the N-position of the carbazole ring has a substituent or is bonded to an adjacent structure.

[0191] When Ar202 is an aliphatic hydrocarbon structure which may have substituents, it is an aliphatic hydrocarbon structure having a linear, branched, or cyclic structure, preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms.

[0192] (i1, i2, i3, i4, k1, k2) i1 and i2 each independently represent integers from 0 to 12, preferably from 1 to 12, more preferably from 1 to 8, and more preferably from 1 to 6. This range is expected to improve solubility and charge transport. i3 preferably represents an integer between 0 and 5, more preferably between 0 and 2, and more preferably 0 or 1. i4 preferably represents an integer between 0 and 2, and more preferably 0 or 1. k1 and k2 each independently represent an integer preferably between 0 and 3, more preferably between 1 and 3, more preferably 1 or 2, and particularly preferably 1.

[0193] (Ar 201 Ar 202 Ar 203 Preferred substituents) Ar 201 Ar 202 Ar 203 The substituents that may be present can be arbitrarily selected, but preferably one or more substituents selected from the substituent group S, and the preferred groups are also as in the substituent group S, but more preferably unsubstituted (hydrogen atom), alkyl, or aryl group, particularly preferably unsubstituted (hydrogen atom) or alkyl, and most preferably unsubstituted (hydrogen atom) or tertiary butyl group, where the tertiary butyl group is Ar 203 If Ar 203 Ar 203 If it does not exist, Ar 202 Ar 202 and Ar 203 If it does not exist, Ar 201 It is preferable that it be substituted with

[0194] (Preferred embodiment of the compound represented by formula (201)) The compound represented by formula (201) is preferably a compound that satisfies one or more of the following conditions (I) to (IV). (I) Phenylene coupled type The structure represented by formula (202) is preferably a structure having a group in which benzene rings are linked, i.e., a benzene ring structure, i1 is 1 to 6, and at least one of the benzene rings is bonded to an adjacent structure at the ortho or meta position. This structure is expected to improve both solubility and charge transport.

[0195] (II)(phenylene)-aralkyl(alkyl) A structure having an aromatic hydrocarbon group or an aromatic heterocyclic group to which an alkyl group or aralkyl group is bonded to ring A1 or ring A2, i.e., Ar 201 is an aromatic hydrocarbon structure or an aromatic heterocyclic structure, i1 is 1 to 6, Ar 202 The structure is an aliphatic hydrocarbon, i2 is 1 to 12, preferably 3 to 8, Ar 203 The structure is a benzene ring structure, i3 is 0 or 1, preferably Ar 201 This is the aforementioned aromatic hydrocarbon structure, more preferably a structure in which 1 to 5 benzene rings are linked together, and more preferably a single benzene ring. This structure is expected to improve both solubility and charge transport.

[0196] (III) Dendron A structure in which a dendron is attached to ring A1 or ring A2, for example, Ar 201 Ar 202 The benzene ring structure, Ar 203 The structure is biphenyl or terphenyl, i1 and i2 are 1 to 6, i3 is 2, and j is 2. This structure is expected to improve both solubility and charge transport.

[0197] (IV)B 201 -L 200 -B 202 B 201 -L 200 -B 202 The structure represented by is preferably the structure represented by the following formula (203) or formula (204).

[0198] [ka]

[0199] In formula (203), R 211 , R 212 , R 213 Each of these independently represents a substituent. In formula (204), ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom, which may have substituents. Ring B3 is preferably a pyridine ring.

[0200] (Preferred phosphorescent material) The phosphorescent material represented by formula (201) is not particularly limited, but preferred materials include the following.

[0201] [ka]

[0202] [ka]

[0203] Furthermore, phosphorescent materials represented by the following formula (205) are also preferred.

[0204] [ka]

[0205] [In formula (205), M 2 R represents a metal, and T represents a carbon or nitrogen atom. 92 ~R 95 Each of these independently represents a substituent. However, if T is a nitrogen atom, then R 94 and R 95 There isn't one.

[0206] In formula (205), M 2 Specific examples include metals selected from groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold are preferred, and divalent metals such as platinum and palladium are particularly preferred.

[0207] Also, in equation (205), R 92 and R 93Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.

[0208] Furthermore, if T is a carbon atom, R 94 and R 95 Each of them is independent of R 92 and R 93 This represents substituents represented by similar examples. Furthermore, if T is a nitrogen atom, R is directly bonded to T. 94 or R 95 It does not exist. Also, R 92 ~R 95 It may further have substituents. The substituents can be the substituents mentioned above. Furthermore, R 92 ~R 95 Any two or more of these groups may be linked together to form a ring.

[0209] (molecular weight) The molecular weight of the phosphorescent material is preferably 5000 or less, more preferably 4000 or less, and particularly preferably 3000 or less. Furthermore, the molecular weight of the phosphorescent material is preferably 800 or more, more preferably 1000 or more, and even more preferably 1200 or more. This molecular weight range allows the phosphorescent materials to mix uniformly with the charge transport material without agglomerating, resulting in a highly efficient luminescent layer.

[0210] A large molecular weight is preferable for phosphorescent materials because it results in high Tg, melting point, and decomposition temperature, providing excellent heat resistance for the phosphorescent material and the formed luminescent layer, and reducing the likelihood of deterioration of film quality due to gas generation, recrystallization, and molecular migration, as well as an increase in impurity concentration due to thermal decomposition of the material. On the other hand, a small molecular weight is preferable for phosphorescent materials because it facilitates the purification of organic compounds.

[0211] <Charge transport material> The charge transport material used in the light-emitting layer is preferably a material having a framework with excellent charge transport properties, and is selected from electron transport materials, hole transport materials, and bipolar materials capable of transporting both electrons and holes.

[0212] Examples of skeletons with excellent charge transport properties include aromatic structures, aromatic amine structures, triarylamine structures, dibenzofuran structures, naphthalene structures, phenanthrene structures, phthalocyanine structures, porphyrin structures, thiophene structures, benzylphenyl structures, fluorene structures, quinacridone structures, triphenylene structures, carbazole structures, pyrene structures, anthracene structures, phenanthroline structures, quinoline structures, pyridine structures, pyrimidine structures, triazine structures, oxadiazole structures, or imidazole structures.

[0213] As an electron transport material, from the viewpoint of having excellent electron transport properties and a relatively stable structure, compounds having pyridine, pyrimidine, or triazine structures are more preferred, and compounds having pyrimidine or triazine structures are even more preferred.

[0214] A hole-transporting material is a compound having a structure that exhibits excellent hole transport properties. Among the central skeletons exhibiting excellent charge transport properties, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure is preferred as a structure with excellent hole transport properties, and a carbazole structure, a dibenzofuran structure, or a triarylamine structure is even more preferred.

[0215] The charge transport material used in the light-emitting layer preferably has a fused ring structure of three or more rings, and more preferably is a compound having two or more fused ring structures of three or more rings, or a compound having at least one fused ring of five or more rings. These compounds increase molecular rigidity, making it easier to suppress the degree of molecular motion that responds to heat. Furthermore, the fused rings of three or more rings and the fused rings of five or more rings preferably have aromatic hydrocarbon rings or aromatic heterocycles, in terms of charge transport properties and material durability.

[0216] Examples of condensed ring structures with three or more rings include anthracene structures, phenanthrene structures, pyrene structures, chrysene structures, naphthacene structures, triphenylene structures, fluorene structures, benzofluorene structures, indenofluorene structures, indolofluorene structures, carbazole structures, indenocarbazole structures, indolocarbazole structures, dibenzofuran structures, and dibenzothiophene structures. From the viewpoint of charge transport and solubility, at least one selected from the group consisting of phenanthrene structures, fluorene structures, indenofluorene structures, carbazole structures, indenocarbazole structures, indolocarbazole structures, dibenzofuran structures, and dibenzothiophene structures is preferred, and from the viewpoint of resistance to charge, carbazole structures or indolocarbazole structures are more preferred.

[0217] In the present invention, from the viewpoint of the durability of the organic electroluminescent element against charge, it is preferable that at least one of the charge transport materials in the light-emitting layer is a material having a pyrimidine skeleton or a triazine skeleton.

[0218] The charge transport material in the light-emitting layer is preferably a polymer material from the viewpoint of excellent flexibility. A light-emitting layer formed using a material with excellent flexibility is preferred as the light-emitting layer of an organic electroluminescent device formed on a flexible substrate. When the charge transport material contained in the light-emitting layer is a polymer material, the molecular weight is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and even more preferably 10,000 to 100,000.

[0219] Furthermore, the charge transport material of the light-emitting layer is preferably low molecular weight, from the viewpoint of ease of synthesis and purification, ease of designing electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in a solvent. When the charge transport material contained in the light-emitting layer is a low molecular weight material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, most preferably 2,000 or less, preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more.

[0220] <Fluorescent materials> The fluorescent material is not particularly limited, but compounds represented by the following formula (211) are preferred.

[0221] [ka]

[0222] In the above equation (211), Ar 241 represents an aromatic hydrocarbon condensed ring structure which may have substituents, and Ar 242 Ar 243 Each of these independently represents an alkyl group, an aromatic hydrocarbon group, an aromatic heterogroup, or a group formed by bonding these together, which may each have substituents. n41 is an integer from 1 to 4.

[0223] Ar 241 Preferably, it represents an aromatic hydrocarbon condensed ring structure having 10 to 30 carbon atoms. Specific examples of ring structures include naphthalene, acenaphthene, fluorene, anthracene, phenathrene, fluorantene, pyrene, tetracene, chrysene, and perylene. Ar 241 More preferably, it is an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms. Specific examples of ring structures include acenaphthene, fluorene, anthracene, phenathrene, fluorantene, pyrene, tetracene, chrysene, and perylene. Ar 241More preferably, it is an aromatic hydrocarbon condensed ring structure having 16 to 18 carbon atoms, and specific examples of ring structures include fluorantene, pyrene, and chrysene.

[0224] n41 is 1 to 4, preferably 1 to 3, more preferably 1 to 2, and most preferably 2.

[0225] Ar 242 Ar 243 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Ar 242 Ar 243 The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms, and most preferably a phenyl group or a naphthyl group. Ar 242 Ar 243 The aromatic heterogroup is preferably an aromatic heterogroup having 3 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 5 to 24 carbon atoms, specifically a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group, with the dibenzofuranyl group being more preferred.

[0226] Ar 241 Ar 242 Ar 243 The substituents that may be present are preferably groups selected from the substituent group S, more preferably hydrocarbon groups included in the substituent group S, and even more preferably hydrocarbon groups among the groups preferred as substituent group S.

[0227] The charge transport material used with the above-mentioned fluorescent material is not particularly limited, but one represented by the following formula (212) is preferred.

[0228] [ka]

[0229] In the above equation (212), R 251 , R252 Each of these is a structure that can be independently represented by equation (213), and R 253 R represents a substituent, 253 If there are multiple values, they may be the same or different, and n43 is an integer between 0 and 8.

[0230] [ka]

[0231] In the above equation (213), * represents the bond with the anthracene ring in equation (212), and Ar 254 Ar 255 Each of these independently represents an aromatic hydrocarbon structure which may have substituents, or a heteroaromatic ring structure which may have substituents, and Ar 254 Ar 255 If there are multiple instances of each, they may be the same or different, n44 is an integer from 1 to 5, and n45 is an integer from 0 to 5.

[0232] Ar 254 Preferably, it is an aromatic hydrocarbon structure having 6 to 30 carbon atoms and being a monocyclic or fused ring, which may have substituents, and more preferably, it is an aromatic hydrocarbon structure having 6 to 12 carbon atoms and being a monocyclic or fused ring, which may have substituents.

[0233] Ar 255 Preferably, it is an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 30 carbon atoms and may have substituents, or an aromatic heterocyclic structure which is a fused ring having 6 to 30 carbon atoms and may have substituents. 255 More preferably, it is an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 12 carbon atoms and may have substituents, or an aromatic heterocyclic structure which is a fused ring having 12 carbon atoms and may have substituents.

[0234] n44 is preferably an integer between 1 and 3, and more preferably 1 or 2. n45 is preferably an integer between 0 and 3, and more preferably between 0 and 2.

[0235] R is a substituent. 253 Ar 254 and Ar 255 The substituents that may be present are preferably groups selected from the substituent group S. More preferably, they are hydrocarbon groups included in substituent group S, and even more preferably, they are hydrocarbon groups among the groups preferred as substituent group S.

[0236] The molecular weight of the fluorescent material and the charge transport material is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less. It is also preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more.

[0237] [Hole Blocking Layer] A hole blocking layer 6 may be provided between the light-emitting layer 5 and the electron injection layer 8, which will be described later. The hole blocking layer 6 is a layer within the electron transport layer that also plays a role in preventing holes moving from the anode 2 from reaching the cathode 9. The hole blocking layer 6 is a layer that is laminated on top of the light-emitting layer 5 so as to be in contact with the interface of the light-emitting layer 5 on the cathode 9 side.

[0238] The hole blocking layer 6 has the role of preventing holes moving from the anode 2 from reaching the cathode 9, and the role of efficiently transporting electrons injected from the cathode 9 toward the light-emitting layer 5.

[0239] The required properties for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet energy level (T1). Examples of materials for the hole blocking layer 6 that satisfy these conditions include mixed ligand complexes such as bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolato)aluminum, metal complexes such as bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum dinuclear metal complex, styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Publication No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Publication No. 7-41759), and phenanthroline derivatives such as basocproine (Japanese Patent Publication No. 10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2,4, and 6 positions, as described in International Publication No. 2005 / 022962, are also preferred as materials for the hole blocking layer 6.

[0240] There are no restrictions on the method of forming the hole blocking layer 6. The hole blocking layer 6 can be formed by wet deposition, vapor deposition, or other methods. The thickness of the hole blocking layer 6 is arbitrary as long as it does not significantly impair the effects of the present invention. The thickness of the hole blocking layer 6 is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0241] [Electron transport layer] The electron transport layer 7 is a layer provided between the light-emitting layer 5 and the cathode 9 for transporting electrons.

[0242] Typically, the electron transport material used for the electron transport layer 7 is a compound that has high electron injection efficiency from the cathode 9 or the adjacent layer on the cathode 9 side, and also has high electron mobility, enabling efficient transport of injected electrons. Examples of compounds that satisfy these conditions include metal complexes such as aluminum and lithium complexes of 8-hydroxyquinoline (Japanese Patent Publication No. 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Patent Publication No. 5-331459), 2-t-butyl-9,10-N,N'-dicyanoanthraquinone diimine, triazine compound derivatives, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

[0243] As the electron transport material used in the electron transport layer 7, electron transporting organic compounds, such as nitrogen-containing heterocyclic compounds like bathophenanthroline or metal complexes like aluminum complexes of 8-hydroxyquinoline, are preferred because they can be doped with alkali metals such as sodium, potassium, cesium, lithium, and rubidium (as described in Japanese Patent Publication No. 10-270171, Japanese Patent Publication No. 2002-100478, Japanese Patent Publication No. 2002-100482, etc.) to achieve both electron injection transport properties and excellent film quality. Furthermore, doping the above-mentioned electron transporting organic compounds with inorganic salts such as lithium fluoride or cesium carbonate is also effective.

[0244] There are no restrictions on the method of forming the electron transport layer 7. The electron transport layer 7 can be formed by wet deposition, vapor deposition, or other methods.

[0245] The thickness of the electron transport layer 7 is arbitrary as long as it does not significantly impair the effects of the present invention. The thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and is typically 300 nm or less, preferably 100 nm or less.

[0246] [Electron injection layer] To efficiently inject electrons from the cathode 9 into the light-emitting layer 5, an electron injection layer 8 may be provided between the electron transport layer 7 and the cathode 9, which will be described later. The electron injection layer 8 is made of an inorganic salt or the like.

[0247] Examples of materials for the electron injection layer 8 include lithium fluoride (LiF), magnesium fluoride (MgF2), lithium oxide (Li2O), and cesium(II) carbonate (CsCO3) (see Applied Physics Letters, 1997, Vol.70, pp.152; Japanese Patent Publication No. 10-74586; IEEE Transactions on Electron Devices, 1997, Vol.44, pp.1245; SID 04 Digest, pp.154, etc.).

[0248] Since the electron injection layer 8 often does not have charge transport properties, it is preferable to use it as an ultrathin film in order to efficiently perform electron injection, and its film thickness is usually 0.1 nm or more, preferably 5 nm or less.

[0249] [cathode] The cathode 9 is an electrode that plays the role of injecting electrons into the layer on the light-emitting layer 5 side.

[0250] Common materials for the cathode 9 include metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and / or tin oxides; metal halides such as copper iodide; carbon black; or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. Of these, metals with low work functions are preferred for efficient electron injection, and suitable metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys thereof, are used. Specific examples include low-work-function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

[0251] The cathode 9 material may consist of only one type, or two or more types may be used in any combination and ratio.

[0252] The thickness of the cathode 9 varies depending on the required transparency. If transparency is required, the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness of the cathode 9 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably around 500 nm or less. If opacity is acceptable, the thickness of the cathode 9 is arbitrary, and the cathode may be the same thickness as the substrate.

[0253] It is also possible to layer different conductive materials on top of cathode 9. For example, to protect a cathode made of a low-work-function metal such as alkali metals like sodium or cesium, or alkaline earth metals like barium or calcium, it is preferable to further laminate a metal layer with a high work function and stability to the atmosphere on top of it, as this increases the stability of the device. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum are used. These materials may be used individually, or two or more may be used in any combination and ratio.

[0254] [Other layers] The organic electroluminescent element of the present invention may have other configurations without departing from the spirit of the invention. For example, as long as its performance is not impaired, there may be any additional layers between the anode 2 and cathode 9 besides the layers described above, and non-essential layers among the layers described above may be omitted.

[0255] Furthermore, the cathode 9 may have one or more layers of another organic layer as a protective layer for the cathode.

[0256] In the layer configuration described above, it is also possible to stack the components other than the substrate in the reverse order. For example, in the layer configuration shown in Figure 1, the other components may be placed on the substrate 1 in the following order: cathode 9, electron injection layer 8, electron transport layer 7, hole blocking layer 6, light-emitting layer 5, hole transport layer 4, hole injection layer 3, and anode 2.

[0257] The organic electroluminescent element of the present invention may be configured as a single organic electroluminescent element, or it may be applied to a configuration in which multiple organic electroluminescent elements are arranged in an array, or it may be applied to a configuration in which the anode and cathode are arranged in an XY matrix.

[0258] Each of the above-mentioned layers may contain components other than those described as materials, as long as they do not significantly impair the effects of the present invention.

[0259] [Organic electroluminescent devices] By providing two or more organic electroluminescent elements that emit light in different colors, an organic electroluminescent device such as an organic EL display device or organic EL lighting can be created. In this organic electroluminescent device, by providing at least one, preferably all, organic electroluminescent elements of the present invention, a high-quality organic electroluminescent device can be provided.

[0260] [Organic EL display device] There are no particular restrictions on the type or structure of the organic EL display device using the organic electroluminescent element of the present invention, and it can be assembled according to conventional methods using the organic electroluminescent element of the present invention. For example, an organic EL display device can be formed using the method described in "Organic EL Display" (Ohmsha, published August 20, 2004, authored by Shizuka Tokito, Chihaya Adachi, and Hideyuki Murata).

[0261] [Organic EL lighting] There are no particular restrictions on the type or structure of the organic EL lighting using the organic electroluminescent element of the present invention, and it can be assembled according to conventional methods using the organic electroluminescent element of the present invention. [Examples]

[0262] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and can be modified and implemented as such without departing from its essence.

[0263] [Example 1] <Preparation of Functional Composition B-1> A polymer compound (P-1) (weight-average molecular weight: approximately 15,000) shown in the following structural formula and an electron-accepting compound (HI-1) shown in the following structural formula were weighed using an electronic balance in a mass ratio of (P-1):(HI-1)=87:13 to obtain hole implantation material 1. Next, hole implantation material 1 was mixed with ethyl 4-methylbenzoate (ethyl p-toluate, boiling point: approximately 232°C, vapor pressure: approximately 6.6 Pa) in a screw vial to a concentration of 2.0% by mass. The screw vial was then placed in a vacuum chamber, and the gaseous portion in the screw vial was replaced with nitrogen by repeating vacuum evacuation and nitrogen purging three times. After that, the mixture was heated at a hot plate temperature of 110°C for 3 hours while stirring at 420 rpm using a magnetic stirrer. After the obtained composition was cooled to room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain functional composition B-1.

[0264] [ka]

[0265] [ka]

[0266] The solubility Ra of (HI-1) in functional composition B-1 and the organic solvent, as determined from the Hansen solubility parameter values ​​calculated from the molecular structural formula using the calculation software HSPiP (Hansen Solubility Parameter in Practice), was 14.8.

[0267] <Preparing the circuit board> An indium tin oxide (ITO) film, a silver-indium compound film, and another indium tin oxide film were sequentially deposited on a 0.5 mm thick glass substrate by sputtering, and an electrode pattern was formed using a general photolithography method. A photosensitive composition A (a liquid-repellent resist) containing a liquid-repellent component with fluorine atoms was coated onto the substrate to a thickness of 1.5 μm, and openings were created using a general photolithography method. The size of the openings was approximately 205 μm along the long axis and approximately 85 μm along the short axis, with 22 openings along the short axis and 7 along the long axis, for a total of 154 openings arranged in a grid pattern.

[0268] The obtained substrates were subjected to ultrasonic cleaning in ultrapure water for 15 minutes, followed by drying in a clean oven preheated to 130°C for 10 minutes. Immediately before applying the composition, the substrates were baked on a hot plate heated to 230°C for 10 minutes to remove any moisture adhering to the surface.

[0269] <Application of the composition> Functional composition B-1 was filled into an inkjet printer cartridge (DMCLCP-11610, manufactured by Fujifilm Corporation) using a micropipette, and then applied to the openings of the substrate using an inkjet printer (DMP-2831, manufactured by Fujifilm Corporation). The ejection voltage of the inkjet printer was adjusted so that the amount of composition ejected from the nozzle of the inkjet head was 10 pL, and 7 drops were applied to each opening. The coating was applied to a total of 1,100 openings: 55 in the short axis direction and 20 in the long axis direction, after which the following drying and firing processes were carried out.

[0270] <Drying, firing> The obtained coating film was placed in a sealed chamber with an openable / closable lid and dried under reduced pressure to 0.1 Pa or less using a multi-stage pump (VMR-050 manufactured by ULVAC, Inc.) that combined a mechanical booster pump and rotary pump oil, thereby forming a functional film.

[0271] Vacuum drying involved first reducing the pressure from atmospheric pressure to 1-10 Pa over 240 seconds, and then reducing it to 0.1 Pa or less over 180 seconds or more to volatilize the solvent components in the composition and form a functional film.

[0272] The functional film was placed on a hot plate heated to 230°C and baked for 30 minutes to obtain functional film 1.

[0273] <Formation of vapor-deposited layer> The obtained functional film was placed in a vacuum chamber, and a hole transport material (model number: HT211, manufacturer: JiLin OLED Material Tech Co., LTD) was heated and deposited to form a hole transport layer. The thickness of the hole transport layer, as shown by the quartz oscillator, was 60 nm.

[0274] Next, aluminum was heated and deposited in a vacuum chamber to form a cathode. The cathode, represented by a quartz crystal oscillator, had a film thickness of 80 nm.

[0275] <Device Evaluation> The resulting device lacks electron transport capabilities and is therefore a hole-only device (HOD), meaning only holes flow through it. A voltage was applied to this HOD so that the anode side was positively charged, and the current-voltage characteristics were obtained. The current density was 15 mA / cm². 2 The required applied voltage was 20.5V.

[0276] [Example 2] In Example 1, the organic solvent used was changed to 3-phenoxytoluene (boiling point: 272°C, vapor pressure: 1.6 Pa), and the procedure was carried out in the same manner as in Example 1 to obtain the current-voltage characteristics. The current density was 15 mA / cm². 2 The applied voltage required to reach this value was 20.2V. At this value, the solubility Ra of (HI-1) and the organic solvent was 16.5.

[0277] [Comparative Example 1] In Example 1, the organic solvent used was changed to 1,1-diphenylpentane (boiling point: 307°C, vapor pressure: 0.17 Pa), and the procedure was carried out in the same manner as in Example 1 to obtain the current-voltage characteristics. The current density obtained was 15 mA / cm². 2 The applied voltage required to reach this value was 21.3V. At this value, the solubility Ra of (HI-1) and the organic solvent was 18.0.

[0278] The results of Examples 1 and 2 and Comparative Example 1 are summarized in Table 1.

[0279] [Table 1]

[0280] As is clear from the results, when the solubility Ra of the electron-accepting compound and the organic solvent is less than 17.0, the solubility is 15 mA / cm². 2 While the applied voltage required to conduct the current was in the 20V range, it increased to the 21V range when the solubility Ra was 17.0 or higher, indicating a higher voltage. This is thought to be because electron-accepting compounds that cannot remain soluble in the solvent aggregated and were further segregated by being attracted to the liquid-repellent bank containing fluorine atoms, preventing sufficient doping of the entire functional film.

[0281] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention. [Explanation of Symbols]

[0282] 1 circuit board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6. Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent element

Claims

1. A step of applying a liquid-repellent photosensitive composition A onto a substrate having a patterned electrode layer, and forming a patterned structure by photolithography, A step of applying a functional composition B containing an organic solvent onto a substrate having the aforementioned structure, A method for manufacturing an organic electroluminescent element, comprising the steps of: volatilizing the organic solvent of the functional composition B by drying to obtain a functional film, in this order, The photosensitive composition A is a composition comprising at least one functional material containing a fluorine atom, The functional composition B is a composition comprising at least one electron-accepting compound containing a fluorine atom and at least one organic solvent. The electron-accepting compound containing the fluorine atom is a compound having a crosslinkable substituent. The crosslinkable substituent is a substituent selected from substituents containing a benzocyclobutene ring, a naphthocyclobutene ring, or an oxetane ring, a vinyl group, an acrylic group, or a styryl group which may have an alkyl substituent. The Hansen solubility parameter (dispersion term: Ds, polarity term: Ps, hydrogen bonding term: Hs) of at least one organic solvent contained in the functional composition B, In relation to the relationship between the Hansen solubility parameter (dispersion term: Dd, polarity term: Pd, hydrogen bonding term: Hd) of at least one electron-accepting compound containing the fluorine atom included in the functional composition B, Solubility Ra = [4 × (Ds - Dd)] (including empirical rules) ２ + (Ps - Pd) ２ + (Hs - HD) ２ ] １／２ The following characteristics are characterized by satisfying the condition of being 17.0 or less: A method for manufacturing an organic electroluminescent element.

2. A step of applying a liquid-repellent photosensitive composition A to a substrate having a patterned electrode layer, and forming a patterned structure by photolithography, A step of applying a functional composition B containing an organic solvent onto a substrate having the aforementioned structure, A method for manufacturing an organic electroluminescent element, comprising the steps of: volatilizing the organic solvent of the functional composition B by drying to obtain a functional film, in this order, The drying is performed under reduced pressure, and in the drying under reduced pressure, the time until the vapor pressure of the organic solvent having the lowest vapor pressure among the organic solvents satisfying the following relationship of Ra is reached is 10 seconds or more and 600 seconds or less. The photosensitive composition A is a composition comprising at least one functional material containing a fluorine atom, The functional composition B is a composition comprising at least one electron-accepting compound containing a fluorine atom and at least one organic solvent. The Hansen solubility parameter (dispersion term: Ds, polarity term: Ps, hydrogen bonding term: Hs) of at least one organic solvent contained in the functional composition B, In relation to the relationship between the Hansen solubility parameter (dispersion term: Dd, polarity term: Pd, hydrogen bonding term: Hd) of at least one electron-accepting compound containing the fluorine atom included in the functional composition B, The solubility Ra = [4 × (Ds - Dd)² + (Ps - Pd)² + (Hs - Hd)²] 1 / 2, including the empirical rule, is characterized by satisfying that it is 17.0 or less. A method for manufacturing an organic electroluminescent element.

3. A method for producing an organic electroluminescent element according to claim 1 or 2, characterized in that the content of the organic solvent that satisfies the relationship of Ra is 30% by mass or more relative to the entire functional composition B.

4. A method for producing an organic electroluminescent element according to claim 1 or 2, characterized in that the content of the electron-accepting compound containing the fluorine atom is 0.01% by mass or more relative to the entire functional composition B.

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