JP7463890B2 - Organic electronic material, ink composition, organic layer, organic electronic element, organic electroluminescence element, lighting device, display element, and display device - Google Patents

Description

Embodiments of the present invention relate to organic electronic materials, ink compositions, organic layers, organic electronic elements, organic electroluminescence elements (also called "organic EL elements"), lighting devices, display elements, and display devices.

Organic EL elements are attracting attention as a large-area solid-state light source, for example, as a replacement for incandescent lamps and gas-filled lamps. They are also attracting attention as a promising self-luminous display to replace liquid crystal displays (LCDs) in the field of flat panel displays (FPDs), and commercialization of these devices is progressing.

Organic EL elements are broadly divided into two types based on the organic materials used: low molecular weight organic EL elements that use low molecular weight compounds, and polymeric organic EL elements that use polymeric compounds. Manufacturing methods for organic EL elements are broadly divided into two types: dry processes in which films are formed mainly in a vacuum system, and coating processes in which films are formed by plate printing such as letterpress printing and intaglio printing, or plateless printing such as inkjet printing. Because coating processes allow for simple film formation, they are expected to be an essential method for future large-screen organic EL displays. For example, Patent Document 1 discloses an organic electronics material that contains a polymer or oligomer with a structure that branches in three directions.

In addition, attempts have been made to mix an ionic compound with a charge transporting compound in order to improve the luminous efficiency and/or lifespan of organic EL elements. For example, Patent Document 2 discloses that an organic electroluminescent element capable of being driven at a low voltage can be obtained by mixing an ionic compound, tris(4-bromophenylaminium hexachloroantimonate) (TBPAH), with a hole transporting polymer compound.

International Publication No. 2010/140553 Japanese Patent Application Laid-Open No. 11-251067

To improve the efficiency and extend the life of organic EL elements, it is desirable to form organic layers into multiple layers and separate the functions of each layer. However, in coating processes, where multiple layers are formed using an ink composition, a problem can arise in that the solvent contained in the upper layer dissolves the lower layer when the upper layer is coated.

In view of the above, an object of an embodiment of the present invention is to provide an organic electronic material and an ink composition that are suitable for a coating process and can form an organic layer that has excellent resistance to solvent solubility (hereinafter also referred to as "solvent resistance"). Another embodiment of the present invention is to provide an organic layer that is suitable for improving the properties of organic electronic elements. Another embodiment of the present invention is to provide an organic electronic element, an organic EL element, a display element, a lighting device, and a display device that have excellent properties.

The inventors have conducted intensive research aimed at achieving the above objective, and have found that an organic layer formed using a material containing a compound having a structural unit exhibiting charge transport properties and having at least one crosslinkable substituent, and a boron compound having a specific structure, exhibits excellent solvent resistance.

Examples of embodiments of the present invention are listed below. The present invention is not limited to the following embodiments.

(1) An organic electronic material that contains a compound having one or more structural units with charge transport properties in the molecule and having at least one crosslinkable substituent, and a boron compound having a halogenated aryl group.

(2) The organic electronic material described in (1), wherein the boron compound is a tri(halogenated aryl)borane.

(3) The organic electronic material according to (1) or (2), wherein the boron compound is tris(pentafluorophenyl)borane.

(4) The organic electronic material according to any one of (1) to (3), wherein the structural unit having charge transport properties includes at least one structural unit selected from the group consisting of structural units including an aromatic amine structure, a carbazole structure, a thiophene structure, a furan structure, and a fluorene structure.

(5) The organic electronic material according to any one of (1) to (4), wherein the crosslinkable substituent includes at least one selected from the group consisting of a carbon-carbon unsaturated bond, a cycloalkyl group having 3 to 5 carbon atoms, a cyclic ether group, a diketene group, an episulfide group, a lactone group, a lactam group, and a heterocycle having a heteroatom.

(6) The organic electronic material according to any one of (1) to (5), wherein the crosslinkable substituent is a cyclic ether group, and the cyclic ether group includes at least one selected from the group consisting of an epoxy group and an oxetanyl group.

(7) The organic electronic material according to any one of (1) to (6), wherein the compound having one or more structural units with charge transport properties in the molecule and having at least one or more crosslinkable substituents is a polymer.

(8) The organic electronic material according to (7), wherein the polymer has a branched structure.

(9) An ink composition comprising the organic electronic material described in any one of (1) to (8) and a solvent.

(10) An organic layer formed using the organic electronics material described in any one of (1) to (8) or the ink composition described in (9).

(11) An organic electronic device comprising at least one organic layer according to (10).

(12) An organic electroluminescence element comprising at least one organic layer according to (10).

(13) The organic electroluminescence element according to (12), further comprising a flexible substrate.

(14) The organic electroluminescence element according to (12), further comprising a resin film substrate.

(15) A display device comprising an organic electroluminescence device according to any one of (12) to (14).

(16) A lighting device comprising an organic electroluminescence element according to any one of (12) to (14).

(17) A display device comprising an organic electroluminescence element according to any one of (12) to (14).

(18) A display device comprising the lighting device described in (16) and a liquid crystal element as a display means.

According to an embodiment of the present invention, it is possible to provide an organic electronic material and an ink composition that are suitable for a coating process and can form an organic layer that has excellent solvent resistance. Furthermore, according to another embodiment of the present invention, it is possible to provide an organic layer that is suitable for improving the properties of an organic electronic element. According to another embodiment of the present invention, it is possible to provide an organic electronic element, an organic EL element, a display element, a lighting device, and a display device that have excellent properties.

1 is a cross-sectional view illustrating an example of an organic EL element according to an embodiment of the present invention.

The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[Organic Electronics Materials]
The organic electronic material according to an embodiment of the present invention contains a compound having a structural unit exhibiting charge transport properties and a crosslinkable substituent (hereinafter also referred to as a "charge transport material"), and a boron compound having a halogenated aryl group (hereinafter also referred to as an "aryl boron compound").

<Charge Transporting Material>
The charge transporting material may be a compound having one or more structural units having charge transporting properties in the molecule and having at least one or more crosslinkable substituents, and may be a low molecular weight compound or a polymer. Examples of the structure of the low molecular weight compound include the following. In the following structure, "T" represents the structural unit T, and "L" represents the structural unit L. The structural unit T and the structural unit L will be described later. In addition, the structural unit having one or more charge transporting properties in the molecule and the crosslinkable substituents can also be those described later.

From the viewpoint of heat resistance and film-forming properties, a polymer is preferable, and from the viewpoint of solubility in organic solvents and ease of purification by sublimation, recrystallization, etc., a low molecular weight compound is preferable. The concept of "polymer" includes so-called "oligomers" that have a small number of repeating structural units. The charge transporting material may be a commercially available material or may be one produced by a method known to those skilled in the art, and there are no particular limitations. The charge transporting material may be used alone or in combination of two or more types.

(Charge-transporting polymer)
The charge transporting polymer will now be described.
The charge transporting polymer has the ability to transport charges. The charge transporting polymer may be linear or have a branched structure. The charge transporting polymer preferably has at least a divalent structural unit L and a monovalent structural unit T constituting a terminal portion, and may further have a trivalent or higher structural unit B constituting a branch portion. The charge transporting polymer may have only one type of each structural unit, or may have multiple types of each structural unit. In the charge transporting polymer, the structural units are bonded to each other at a "monovalent" to "trivalent or higher" bonding site.

(Structure of charge transporting polymer)
Examples of partial structures contained in the charge transporting polymer include the following. The charge transporting polymer is not limited to polymers having the following partial structures. In the partial structures, "L" represents a structural unit L, "T" represents a structural unit T, and "B" represents a structural unit B. In the partial structures contained in the charge transporting polymer shown below, "*" in the formula represents a bonding site with another structural unit. In the partial structures below, multiple Ls may be the same structural unit or different structural units. The same applies to T and B.

Linear charge transport polymer

Charge-transporting polymer with branched structure

(Structural unit L)
The structural unit L is a divalent structural unit having charge transportability. The structural unit L is not particularly limited as long as it contains an atomic group having the ability to transport charge. For example, the structural unit L is selected from substituted or unsubstituted aromatic amine structures, carbazole structures, thiophene structures, fluorene structures, benzene structures, biphenylene structures, terphenylene structures, naphthalene structures, anthracene structures, tetracene structures, phenanthrene structures, dihydrophenanthrene structures, pyridine structures, pyrazine structures, quinoline structures, isoquinoline structures, quinoxaline structures, acridine structures, diazaphenanthrene structures, furan structures, pyrrole structures, oxazole structures, oxadiazole structures, thiazole structures, thiadiazole structures, triazole structures, benzothiophene structures, benzoxazole structures, benzoxadiazole structures, benzothiazole structures, benzothiadiazole structures, benzotriazole structures, and structures containing one or more of these. The aromatic amine structure is preferably a triarylamine structure, more preferably a triphenylamine structure.

In one embodiment, from the viewpoint of obtaining excellent hole transport properties, the structural unit L is preferably selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a pyrrole structure, and a structure containing one or more of these, and more preferably selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, and a structure containing one or more of these. In another embodiment, from the viewpoint of obtaining excellent electron transport properties, the structural unit L is preferably selected from a substituted or unsubstituted fluorene structure, a benzene structure, a phenanthrene structure, a pyridine structure, a quinoline structure, and a structure containing one or more of these.

Specific examples of the structural unit L include the following. The structural unit L is not limited to the following.

Each R independently represents a hydrogen atom or a substituent. All R may be hydrogen atoms. In addition, when R is a substituent, the substituent is preferably selected from the group consisting of -R ¹ , -OR ² , -SR ³ , -OCOR ⁴ , -COOR ⁵ , -SiR ⁶ R ⁷ R ⁸ , a halogen atom, and a group containing a crosslinkable substituent described below. Each of R ¹ to R ⁸ independently represents a hydrogen atom; a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms; or an aryl group or heteroaryl group having 2 to 30 carbon atoms. The alkyl group may be further substituted with an aryl group or heteroaryl group having 2 to 20 carbon atoms, and the aryl group or heteroaryl group may be further substituted with a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms. R is preferably a hydrogen atom, an alkyl group, an aryl group, or an alkyl-substituted aryl group. Ar represents an arylene group or heteroarylene group having 2 to 30 carbon atoms. An aryl group refers to an atomic group obtained by removing one hydrogen atom from an aromatic hydrocarbon. A heteroaryl group refers to an atomic group obtained by removing one hydrogen atom from an aromatic heterocycle. An arylene group refers to an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon. In addition, a heteroarylene group refers to an atomic group obtained by removing two hydrogen atoms from an aromatic heterocycle.

Specific examples of aromatic hydrocarbons include benzene, naphthalene, anthracene, tetracene, fluorene, and phenanthrene. Specific examples of aromatic heterocycles include pyridine, pyrazine, quinoline, isoquinoline, acridine, phenanthroline, furan, pyrrole, thiophene, carbazole, oxazole, oxadiazole, thiadiazole, triazole, benzoxazole, benzoxadiazole, benzothiadiazole, benzotriazole, and benzothiophene.

In addition, from the viewpoint of improving the remaining film rate of the organic layer described later, it is preferable that R in the above structure is a structural unit L that is an electron-withdrawing group, and for example, it is preferable that the structural unit L contains a halogen atom such as a fluoro group that is an electron-withdrawing group.

(Structural unit T)
The structural unit T is a monovalent structural unit constituting the terminal portion of the charge transporting polymer. The structural unit T is not particularly limited, and is selected from, for example, a substituted or unsubstituted aromatic hydrocarbon structure, an aromatic heterocyclic structure, and a structure containing one or more of these. The structural unit T may have the same structure as the structural unit L. In one embodiment, the structural unit T is preferably a substituted or unsubstituted aromatic hydrocarbon structure, more preferably a substituted or unsubstituted benzene structure, from the viewpoint of imparting durability without reducing the transportability of the charge. In another embodiment, as described later, the charge transporting polymer may have a structure containing a structural unit T having a crosslinkable substituent at the terminal portion. The details of the crosslinkable substituent will be described later. The structural unit T may have the same structure as the structural unit L except for the valence, or may have a different structure.

Specific examples of structural unit T include the following. Structural unit T is not limited to the following.

R may be a hydrogen atom or a substituent as exemplified for R in the structural unit L. When the charge transport polymer has a crosslinkable substituent at the end, it is preferable that at least one of R is a group containing a crosslinkable substituent. In addition, from the viewpoint of improving the remaining film rate of the organic layer, the structural unit T in which R in the above structure is an electron-withdrawing group is preferable, and for example, the structural unit T preferably contains a halogen atom such as a fluoro group that is an electron-withdrawing group, more preferably a perhalogenated alkyl group, even more preferably a perfluoroalkyl group, and particularly preferably a perfluoromethyl group. Furthermore, the structural unit T in which R in the above structure contains a crosslinkable substituent is preferable, and for example, it is preferable to contain a cyclic ether group such as an epoxy group (oxiranyl group) or an oxetanyl group, and it is more preferable that the benzene structure in the above structure and the cyclic ether group are ether-bonded.

(Structural unit B)
The structural unit B is a trivalent or higher structural unit constituting a branched portion when the charge transporting polymer has a branched structure. From the viewpoint of improving the durability of the organic electronics element, the structural unit B is preferably a hexavalent or lower structural unit, more preferably a trivalent or tetravalent structural unit. The structural unit B is preferably a unit having charge transport properties. For example, from the viewpoint of improving the durability of the organic electronics element, the structural unit B is selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a condensed polycyclic aromatic hydrocarbon structure, and a structure containing one or more of these. The structural unit B may have the same structure as the structural unit L or a different structure other than the valence, and may have the same structure as the structural unit T or a different structure.

Specific examples of structural unit B include the following. Structural unit B is not limited to the following.

W represents a trivalent linking group, for example, an arenetriyl group or a heteroarenetriyl group having 2 to 30 carbon atoms. The arenetriyl group is an atomic group obtained by removing three hydrogen atoms from an aromatic hydrocarbon. The heteroarenetriyl group is an atomic group obtained by removing three hydrogen atoms from an aromatic heterocycle. Each Ar independently represents a divalent linking group, for example, an arylene group or a heteroarylene group having 2 to 30 carbon atoms. Ar is preferably an arylene group, more preferably a phenylene group. Y represents a divalent linking group, for example, a divalent group obtained by removing one hydrogen atom from a group having one or more hydrogen atoms among the substituents listed as R (excluding groups containing crosslinkable substituents) in the structural unit L. Z represents either a carbon atom, a silicon atom, or a phosphorus atom. In the structural unit, the fused ring, W, Y, and Ar may have a substituent, and examples of the substituent include the substituents listed as R in the structural unit L.

(Crosslinkable Substituent)
In one embodiment, from the viewpoint of curing by a polymerization reaction and changing the solubility in a solvent, the charge transporting polymer preferably has at least one crosslinkable substituent. The "crosslinkable substituent" refers to a functional group that can form intramolecular and/or intermolecular bonds with each other by application of heat and/or light.

Examples of crosslinkable substituents include groups having a carbon-carbon unsaturated bond (e.g., vinyl group, allyl group, butenyl group, ethynyl group, acryloyl group, acryloyloxy group, acryloylamino group, methacryloyl group, methacryloyloxy group, methacryloylamino group, vinyloxy group, vinylamino group, etc.), groups having a small ring (e.g., cycloalkyl groups having 3 to 5 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, etc.; cycloalkenyl groups having 3 to 5 carbon atoms such as cyclopropenyl group, cyclobutenyl group, etc.; cyclic ether groups such as epoxy group (oxiranyl group) and oxetanyl group; diketene group; episulfide group; lactone group; lactam group, etc.), and groups having a heterocycle with a heteroatom (e.g., furan-yl group, pyrrol-yl group, thiophen-yl group, silol-yl group). As the crosslinkable substituent, in particular, ethynyl group, vinyl group, acryloyl group, methacryloyl group, cyclobutenyl group, epoxy group, and oxetanyl group are preferred, and from the viewpoint of transparency and characteristics of organic electronics elements, vinyl group, cyclobutenyl group, epoxy group, or oxetanyl group are more preferred, and from the viewpoint of reactivity, epoxy group or oxetanyl group is even more preferred. In addition, the above-mentioned group having a carbon-carbon unsaturated bond, group having a small ring, and group having a heterocycle having a heteroatom may have a substituent, and for example, it is preferable that the group has an alkyl group.

From the viewpoint of increasing the degree of freedom of the crosslinkable substituent and facilitating the polymerization reaction, the main skeleton of the charge transport polymer and the crosslinkable substituent may be linked by an alkylene chain. In addition, for example, when an organic layer is formed on an electrode, from the viewpoint of improving affinity with a hydrophilic electrode such as ITO (indium oxide-tin oxide), the main skeleton of the charge transport polymer and the crosslinkable substituent may be linked by a hydrophilic chain such as an ethylene glycol chain or a diethylene glycol chain. Furthermore, from the viewpoint of facilitating the preparation of a monomer used to introduce a crosslinkable substituent, the charge transport polymer may have an ether bond or an ester bond at the terminal of the alkylene chain and/or the hydrophilic chain, i.e., at the connection between these chains and the crosslinkable substituent, and/or at the connection between these chains and the skeleton of the charge transport polymer. The aforementioned "group containing a crosslinkable substituent" means the crosslinkable substituent itself, or a group in which the crosslinkable substituent and an alkylene chain or the like are combined. As the group containing a crosslinkable substituent, for example, the groups exemplified in International Publication No. 2010/140553 can be suitably used.

The crosslinkable substituent may be introduced into the terminal portion of the charge transport polymer (i.e., the structural unit T), into a portion other than the terminal portion (i.e., the structural unit L or B), or into both the terminal portion and the portion other than the terminal portion. From the viewpoint of curability, it is preferable that it is introduced into at least the terminal portion, and from the viewpoint of achieving both curability and charge transportability, it is preferable that it is introduced into only the terminal portion. In addition, when the charge transport polymer has a branched structure, the crosslinkable substituent may be introduced into the main chain of the charge transport polymer, into the side chain, or into both the main chain and the side chain.

From the viewpoint of contributing to the change in solubility, it is preferable that the crosslinkable substituent is contained in a large amount in the charge transport polymer. On the other hand, from the viewpoint of not interfering with the charge transport property, it is preferable that the amount of the crosslinkable substituent contained in the charge transport polymer is small. The content of the crosslinkable substituent can be appropriately set taking these into consideration.

For example, the number of crosslinkable substituents per molecule of the charge transport polymer is preferably 2 or more, more preferably 3 or more, from the viewpoint of obtaining a sufficient change in solubility. Also, the number of crosslinkable substituents is preferably 1,000 or less, more preferably 500 or less, from the viewpoint of maintaining charge transportability.

The number of crosslinkable substituents per molecule of the charge transport polymer can be calculated as an average value using the amount of crosslinkable substituents (e.g., the amount of monomer having a crosslinkable substituent) used to synthesize the charge transport polymer, the amount of monomer corresponding to each structural unit, the weight average molecular weight of the charge transport polymer, etc. Also, the number of crosslinkable substituents can be calculated as an average value using the ratio of the integral value of the signal derived from the crosslinkable substituent to the integral value of the entire spectrum in the ¹ H NMR (nuclear magnetic resonance) spectrum of the charge transport polymer, the weight average molecular weight of the charge transport polymer, etc. Because it is simple, when the amount of charge is clear, it is preferable to adopt the value calculated using the amount of charge.

(Number average molecular weight)
The number average molecular weight of the charge transporting polymer can be appropriately adjusted in consideration of solubility in a solvent, film-forming property, etc. From the viewpoint of excellent charge transportability, the number average molecular weight is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more. In addition, from the viewpoint of maintaining good solubility in a solvent and facilitating preparation of an ink composition, the number average molecular weight is preferably 1,000,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less.

(Weight average molecular weight)
The weight average molecular weight of the charge transporting polymer can be appropriately adjusted in consideration of solubility in a solvent, film-forming property, etc. From the viewpoint of excellent charge transportability, the weight average molecular weight is preferably 1,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more. In addition, from the viewpoint of maintaining good solubility in a solvent and facilitating preparation of an ink composition, the weight average molecular weight is preferably 1,000,000 or less, more preferably 700,000 or less, and even more preferably 400,000 or less.

The number average molecular weight and weight average molecular weight can be measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene.

(Proportion of structural units)
The ratio of the structural unit L contained in the charge transporting polymer is preferably 10 mol % or more, more preferably 20 mol % or more, and even more preferably 30 mol % or more, based on the total structural units, from the viewpoint of obtaining sufficient charge transportability. Also, the ratio of the structural unit L is preferably 95 mol % or less, more preferably 90 mol % or less, and even more preferably 85 mol % or less, based on the total structural units, taking into consideration the structural unit T and the structural unit B introduced as necessary.

The proportion of structural unit T contained in the charge transport polymer is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on all structural units, from the viewpoint of improving the characteristics of the organic electronics element, or from the viewpoint of suppressing an increase in viscosity and smoothly synthesizing the charge transport polymer. Furthermore, the proportion of structural unit T is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, based on all structural units, from the viewpoint of obtaining sufficient charge transportability.

When the charge transport polymer has structural unit B, the proportion of structural unit B is preferably 1 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, based on all structural units, from the viewpoint of improving the durability of the organic EL element. Furthermore, the proportion of structural unit B is preferably 50 mol % or less, more preferably 40 mol % or less, and even more preferably 30 mol % or less, based on all structural units, from the viewpoint of suppressing an increase in viscosity and smoothly synthesizing the charge transport polymer, or from the viewpoint of obtaining sufficient charge transportability.

When the charge transport polymer has a crosslinkable substituent, the proportion of the crosslinkable substituent is preferably 0.1 mol % or more, more preferably 1 mol % or more, and even more preferably 3 mol % or more, based on all structural units, from the viewpoint of efficiently curing the charge transport polymer. Also, the proportion of the crosslinkable substituent is preferably 70 mol % or less, more preferably 60 mol % or less, and even more preferably 50 mol % or less, based on all structural units, from the viewpoint of obtaining good charge transport properties. Note that the "proportion of crosslinkable substituent" here refers to the proportion of structural units having a crosslinkable substituent.

Considering the balance of charge transportability, durability, productivity, etc., the ratio (molar ratio) of the structural unit L and the structural unit T is preferably L:T=100:1-70, more preferably 100:3-50, and even more preferably 100:5-30. Furthermore, when the charge transporting polymer has the structural unit B, the ratio (molar ratio) of the structural unit L, the structural unit T, and the structural unit B is preferably L:T:B=100:10-200:10-100, more preferably 100:20-180:20-90, and even more preferably 100:40-160:30-80.

The ratio of structural unit can be obtained by using the amount of monomer corresponding to each structural unit used to synthesize charge transport polymer.In addition, the ratio of structural unit can be calculated as an average value by utilizing the integral value of the spectrum derived from each structural unit in the ¹ H NMR spectrum of charge transport polymer.Because it is simple, when the amount of charge is clear, the value obtained by using the amount of charge is preferably adopted.

(Method of Producing Charge-Transporting Polymer)
The charge transporting polymer can be produced by various synthesis methods, and is not particularly limited. For example, known coupling reactions such as Suzuki coupling, Negishi coupling, Sonogashira coupling, Stille coupling, and Buchwald-Hartwig coupling can be used. Suzuki coupling is a cross-coupling reaction between an aromatic boronic acid derivative and an aromatic halide using a Pd catalyst. According to Suzuki coupling, the charge transporting polymer can be easily produced by bonding desired aromatic rings together.

In the coupling reaction, for example, Pd(0) compounds, Pd(II) compounds, Ni compounds, etc. are used as catalysts. In addition, catalyst species generated by mixing precursors such as tris(dibenzylideneacetone)dipalladium(0) and palladium(II) acetate with a phosphine ligand can also be used. Regarding the method of synthesizing the charge transporting polymer, for example, the description in International Publication No. 2010/140553 can be used.

<Arylboron compounds>
The boron compound having an aryl halide group (aryl boron compound) may be a compound in which one or more aryl halide groups are bonded to a boron atom. Since the boron atom is a group 13 atom, up to three hydrogen atoms or substituents can be bonded to the boron atom, and the boron compound may be any of monoaryl boranes in which one aryl group is bonded, bisaryl boranes in which two aryl groups are bonded, and triaryl boranes in which three aryl groups are bonded. One or more of the aryl groups are "halogenated aryl groups" substituted with halogen atoms. The substituents bonded to the boron atom may be the same or different from each other. From the viewpoint of the stability of the aryl boron compound, triaryl boranes are preferred, and tri(aryl halide) boranes are more preferred.

In addition, the halogenated aryl group is not limited to an aryl group substituted with a halogen atom, but also includes a heteroaryl group substituted with a halogen atom.

Examples of aryl groups include condensed ring aromatic hydrocarbon groups such as phenyl, naphthyl, anthryl, tetryl, and pyrenyl; and polyphenyl groups such as biphenyl and terphenyl. Examples of heteroaryl groups include heterocyclic aromatic groups such as pyridyl, furanyl, and thiophenyl.

The aryl group may be substituted with a functional group containing an atom other than a halogen atom, carbon atom, or hydrogen atom, and from the viewpoint of the stability of the aryl boron compound, an aryl group substituted with an electron-withdrawing functional group is preferred. Examples of electron-withdrawing groups include an ether group, a nitro group, and a cyano group. The aryl group preferably has one or more substituents.

Examples of halogen atoms contained in the halogenated aryl group include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. From the viewpoint of the stability of the aryl boron compound, it is preferable that the halogenated aryl group contains a fluorine atom. Also, from the viewpoint of obtaining excellent stability against electrons, it is preferable that the number of halogen atoms contained in the halogenated aryl group is large.

Specific examples of triarylboranes include the following, but arylboron compounds are not limited to these.

In the above structural formula, Ar ¹ to Ar ³ each independently represent an aryl group or a halogenated aryl group, and at least one of Ar ¹ to Ar ³ is a halogenated aryl group.

In addition, the triarylborane is preferably a tri(halogenated aryl)borane having a structure as shown in the following structural formula.

In the above structural formula, R ¹ to R ³ represent a hydrogen atom or a substituent, and the substituents are preferably each independently selected from the group consisting of -R ¹¹ , -OR ¹² , -SR ¹³ , -OCOR ¹⁴ , -COOR ¹⁵ , and -SiR ¹⁶ R ¹⁷ R ^18. R ¹¹ to R ¹⁸ are each independently a hydrogen atom or at least one selected from the group consisting of linear, cyclic, or branched alkyl groups, alkenyl groups, alkynyl groups, and alkoxy groups having 1 to 22 carbon atoms, and aryl groups and heteroaryl groups having 2 to 30 carbon atoms. The aryl groups and heteroaryl groups may further have a substituent. The substituent is preferably a linear, cyclic, or branched alkyl group having 1 to 22 carbon atoms, or a heteroaryl group having 2 to 30 carbon atoms.

In the above structural formula, X ¹ to X ³ represent a halogen atom, and the halogen atom is independently at least one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. From the viewpoint of stability of the boron compound, it is preferable that the aryl boron compound contains a fluorine atom.

In the above structural formula, L, M, and N each independently represent an integer of 0 to 5, l represents an integer satisfying 5-L, m represents an integer satisfying 5-M, and n represents an integer satisfying 5-N, and at least one of L, M, and N is an integer of 1 or more. In addition, when l, m, n, L, M, and N are integers of 2 or more, each substituent or each halogen atom may be the same or different, for example, when l is 2, two R ¹ may be the same substituent or may be different substituents. In addition, from the viewpoint of obtaining excellent stability against electrons, the number of halogen atoms (the numbers of L, M, and N) is preferably large, and for example, the number of halogen atoms substituted on one phenyl group is preferably 1 or more, more preferably 3 or more, and particularly preferably 5.

The above-mentioned halogenated aryl group has the effect of increasing the Lewis acidity of the aryl boron compound and stabilizing the aryl boron compound. By improving the stability of the boron compound having a halogenated aryl group in this embodiment, decomposition in the atmosphere or at high temperatures can be suppressed, and the handling of the mixture is improved. In addition, as will be described later, the boron compound having a halogenated aryl group in this embodiment can be used as a polymerization initiator to promote the curing of the charge transport polymer, and since it is stable because it makes the polymerization reaction easier to proceed, it is possible to increase the residual film rate of the organic layer formed using the boron compound having a halogenated aryl group (improve solvent resistance).

Specific examples of the above structural formula include the following. The above structural formula is not limited to the following.

The aryl boron compound represented by the above structural formula is tris(pentafluorophenyl)borane, and it is preferable to use tris(pentafluorophenyl)borane from the viewpoint of ease of handling. Tris(pentafluorophenyl)borane is a relatively stable compound in air at room temperature, and therefore can be easily handled.

The aryl boron compounds may be used alone or in combination of two or more compounds.

<Other ingredients>
Additives such as antioxidants, anti-yellowing agents, ultraviolet absorbers, visible light absorbers, colorants, plasticizers, stabilizers, and fillers may be added as optional components within a range that does not adversely affect the properties of the organic electronics element. In addition, an ionic compound may be mixed with the organic electronics material for the purpose of improving the luminous efficiency and/or life of the organic EL element. By mixing and using an ionic compound, the electrical conductivity, stability, and life of the organic EL element are expected to be improved.

(Ionic Compounds)
In the present specification and the like, the term "ionic compound" refers to a compound consisting of a cation and an anion. From the viewpoint of electrical conductivity and stability, it is preferable that the anion contains an electron-withdrawing organic substituent, and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, alkylsulfonyl groups substituted with alkyls such as cyano groups, thiocyano groups, nitro groups, and mesyl groups, arylsulfonyl groups substituted with aryls such as tosyl groups and mesityl groups, acyl groups having a carbon number of usually 1 to 12, preferably 6 or less, such as formyl groups, acetyl groups, and benzoyl groups, alkoxycarbonyl groups having a carbon number of usually 2 to 10, preferably 7 or less, such as methoxycarbonyl groups and ethoxycarbonyl groups, and phenoxycarbonyl groups and pyridyloxycarbonyl groups having a carbon number of usually 1 to 10, preferably 7 or less, such as pyridyloxycarbonyl groups. Examples of such groups include an aryloxycarbonyl group having an aromatic hydrocarbon group or an aromatic heterocyclic group which is usually 3 or more, preferably 4 or more and 25 or less, and preferably 15 or less; an acyloxy group having a carbon atom of usually 2 to 20, such as acetoxy; a haloalkyl, haloalkenyl, haloalkynyl group, a pentafluorophenyl group, and the like which are linear, branched, or cyclic alkyl, alkenyl, or alkynyl groups having a carbon atom of usually 1 to 10, preferably 6 or less, substituted with a halogen atom such as a fluorine atom or a chlorine atom; and a haloaryl group having a carbon atom of usually 6 to 20, such as a pentafluorophenyl group.

The cation in the ionic compound is not particularly limited, but is preferably a monovalent cation from the viewpoint of reactivity and ease of handling. The cation in the ionic compound is more preferably iodonium, sulfonium, phosphonium, carbenium (trityl), anilinium, bismuthonium, ammonium, selenium, pyridinium, imidazolium, oxonium, quinolinium, pyrrolidinium, aminium, immonium, tropylium, morpholinium, piperidinium, quinolium, isoquinolium, thiazonium, acridium, etc.

The above cations may be contained in the polymer. Examples of cations contained in the polymer are described in JP-A-2009-57436 and JP-A-2017-59745.

From the viewpoint of improving charge transportability, the ionic compound is preferably an onium salt, which refers to a compound consisting of a cation, such as a sulfonium ion, an iodonium ion, a selenium ion, an ammonium ion, a phosphonium ion, an oxonium ion, or a bismuthonium ion, and a counter anion. Examples of the anion include halogen ions such as F ^- , Cl ^- , Br ^- , and I ^- ; OH ^- ; ClO ₄ ^- ; sulfonate ions such as FSO ₃ ^- , ClSO ₃ ^- , CH ₃ SO ₃ ^- , C ₆ H ₅ SO ₃ ^- , and CF ₃ SO ₃ ^- ; sulfate ions such as HSO ₄ ^- and SO ₄ ^2- ; carbonate ions such as HCO ₃ ^- and CO ₃ ^2- ; phosphate ions such as H ₂ PO ₄ ^- , HPO ₄ ^2- , and PO ₄ ^3- ; fluorophosphate ions such as PF ₆ ^- and PF ₅ OH ^- ; borate ions such as BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^- , and B(C ₆ H ₄ CF ₃ ) ₄ ^- ; and AlCl ₄ ^- ; BiF ₆ ^- ; fluoroantimonate ions such as SbF ₆ ^- and SbF ₅ OH ^- ; and fluoroarsenate ions such as AsF ₆ ^- and AsF ₅ OH ^- .

The ionic compounds may be used alone or in combination of two or more.

(Polymerization initiator)
The organic electronics material may contain a polymerization initiator. Here, the above aryl boron compound and/or ionic compound can be used as a polymerization initiator that promotes the curing of the charge transport polymer. The trigger for initiating polymerization may be any trigger that exhibits the ability to polymerize a polymerizable substituent by application of heat, light, microwaves, radiation, electron beams, or the like, and is not particularly limited. However, it is preferable that the polymerization is initiated by light irradiation and/or heating, and it is most preferable that the polymerization is initiated by heating. The aryl boron compound and/or ionic compound in this embodiment can be used as a thermal polymerization initiator. That is, in this embodiment, at least one of the aryl boron compounds can be included as a thermal polymerization initiator. As a result, the charge transport polymer in this embodiment undergoes a thermal polymerization reaction, and thus it is possible to impart solvent resistance to the organic thin film. In addition, in this embodiment, in addition to the aryl boron compound, other polymerization initiators such as a photopolymerization initiator may be used in combination, and a sensitizer for improving photosensitivity and/or heat sensitivity may be included.

In this embodiment, when an aryl boron compound that can be used as a thermal polymerization initiator is used to impart solvent resistance to an organic layer (organic thin film), the polymerization initiator is preferably used in an amount of 0.1 to 50% by mass, more preferably 0.1 to 25% by mass, and even more preferably 0.1 to 20% by mass, based on the charge transport compound. If the ratio of the polymerization initiator mixed is less than this, polymerization does not proceed efficiently and the solubility cannot be changed sufficiently. If the ratio is more than this, a large amount of polymerization initiator and/or decomposition products remain, reducing the effectiveness of cleaning.

[Ink composition]
The ink composition of the present embodiment is characterized by containing the organic electronic material and a solvent described above, and may contain other additives, such as a polymerization inhibitor, a stabilizer, a thickener, a gelling agent, a flame retardant, an antioxidant, a reduction inhibitor, an oxidizing agent, a reducing agent, a surface modifier, an emulsifier, an antifoaming agent, a dispersing agent, a surfactant, etc. Examples of the solvent include water, alcohols such as methanol, ethanol, and isopropyl alcohol, alkanes such as pentane, hexane, and octane, cyclic alkanes such as cyclohexane, aromatic solvents such as benzene, toluene, xylene, mesitylene, tetralin, and diphenylmethane, aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylbenzene, dimethyl ether ... Examples of the solvent include aromatic ethers such as ethyl anisole and 2,4-dimethyl anisole; aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate and n-butyl benzoate; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; and others such as dimethyl sulfoxide, tetrahydrofuran, acetone, chloroform and methylene chloride. However, aromatic solvents, aliphatic esters, aromatic esters, aliphatic ethers and aromatic ethers are preferably used.

In the ink composition of this embodiment, the content of the organic electronic material relative to the solvent is preferably 0.1 to 50% by mass from the viewpoint of applicability to various coating processes. From the viewpoint of reducing the residual solvent during film formation, the content of the organic electronic material is more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. Furthermore, from the viewpoint of dissolving the organic electronic material uniformly, the content is more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[Organic layer]
The organic layer of the present embodiment is a layer formed using the organic electronic material or ink composition. By using an organic electronic material or ink composition containing a solvent, an organic layer can be well formed by a coating method. Examples of the coating method include known methods such as spin coating; casting; immersion; plate printing methods such as letterpress printing, intaglio printing, offset printing, lithographic printing, letterpress reverse offset printing, screen printing, and gravure printing; and plateless printing methods such as inkjet printing. When the organic layer is formed by a coating method, the organic layer (coated layer) obtained after coating may be dried using a hot plate or an oven to remove the solvent.

When the organic electronic material contains a charge transport material having a crosslinkable substituent and/or a compound having a crosslinkable substituent, the polymerization reaction can be advanced by light irradiation, heat treatment, etc., and the solubility of the organic layer can be changed. In the organic electronic material, the aryl boron compound and/or the ionic compound can function as a polymerization initiator. By stacking organic layers with changed solubility, it becomes possible to easily achieve multi-layering of organic electronic elements. For the method of forming the organic layer, for example, the description in International Publication No. 2010/140553 can be cited.

The thickness of the organic layer after drying or curing is preferably 0.1 nm or more, more preferably 1 nm or more, and even more preferably 3 nm or more, from the viewpoint of improving the efficiency of charge transport. In addition, the thickness of the organic layer is preferably 300 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less, from the viewpoint of reducing the electrical resistance.

In the method for producing the organic layer, a thin film is formed from a composition obtained by mixing the above-mentioned electron-withdrawing compound, which is a charge-transporting material, and the thermal polymerization initiator, and then the thin film is heated in a vacuum, in air, or in an inert gas atmosphere such as nitrogen or argon. There are no particular limitations on the heating temperature and time as long as the polymerization reaction can proceed sufficiently, but the temperature is preferably 300°C or less, more preferably 200°C or less, and even more preferably 150°C or less, since various substrates can be used. The time is preferably 8 hours or less, more preferably 2 hours or less, and even more preferably 1 hour or less, from the viewpoint of increasing productivity.

The organic layer of this embodiment can be used in the organic electronics elements and organic EL elements described below, and both elements have a lower driving voltage and a longer emission life than conventional elements.

[Organic Electronics Devices]
The organic electronics element of the present embodiment includes at least one of the organic layers. Examples of the organic electronics element include an organic EL element such as an organic light-emitting diode (OLED), an organic photoelectric conversion element, and an organic transistor. The organic electronics element preferably has a structure in which an organic layer is disposed between at least a pair of electrodes. The organic electronics element of the present embodiment is not particularly limited as long as it includes a light-emitting layer, an organic layer, an anode, a cathode, and a substrate. The organic layer can be used as a hole injection layer, an electron injection layer, a hole transport layer, or an electron transport layer.

[Organic EL element]
The organic EL element of the present embodiment is characterized by having at least one organic layer made of an organic electronic material containing a charge transport material and an aryl boron compound. The organic EL element of the present embodiment is not particularly limited as long as it has a light emitting layer, an anode, a cathode, and a substrate. The organic layer can be used as a hole injection layer, an electron injection layer, a hole transport layer, or an electron transport layer. It is preferable to apply the organic layer of the present embodiment to the hole injection layer or the hole transport layer.

Figure 1 is a cross-sectional schematic diagram showing one embodiment of an organic EL element. The organic EL element shown in Figure 1 is an element with a multi-layer structure, in which a substrate 8, an anode 2, a hole injection layer 3, a hole transport layer 6, a light-emitting layer 1, an electron transport layer 7, an electron injection layer 5, and a cathode 4 are laminated in this order. Each layer will be described in detail below.

(Light Emitting Layer)
The material used for the light-emitting layer may be a low molecular weight compound or a polymer, and dendrimers and the like can also be used. Examples of low molecular weight compounds that utilize fluorescent emission include perylene, coumarin, rubrene, quinacridone, dyes for dye lasers (e.g., rhodamine, DCM1, etc.), aluminum complexes (e.g., Tris(8-hydroxyquinolinato)aluminum(III) (Alq3)), stilbene, and derivatives thereof. Examples of polymers that utilize fluorescent emission include polyfluorene, polyphenylene, polyphenylenevinylene (PPV), polyvinylcarbazole (PVK), fluorene-benzothiadiazole copolymers, fluorene-triphenylamine copolymers, and derivatives and mixtures thereof.

On the other hand, in recent years, in order to improve the efficiency of organic EL elements, phosphorescent organic EL elements have been actively developed. In phosphorescent organic EL elements, it is possible to use not only the energy of the singlet state but also the energy of the triplet state, and in principle, it is possible to increase the internal quantum yield to 100%. In phosphorescent organic EL elements, phosphorescence is extracted by doping a metal complex phosphorescent material containing a heavy metal such as platinum or iridium as a phosphorescent dopant into a host material (see M.A. Baldo et al., Nature, Vol. 395, p. 151 (1998), M.A. Baldo et al., Applied Physics Letters, Vol. 75, p. 4 (1999), M.A. Baldo et al., Nature, Vol. 403, p. 750 (2000)).

From the viewpoint of improving efficiency, it is preferable to use a phosphorescent material in the light-emitting layer of the organic EL element of this embodiment as well. As the phosphorescent material, a metal complex containing a central metal such as Ir or Pt can be suitably used. Specifically, examples of the Ir complex include FIr(pic) [iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C ² ]picolinate] which emits blue light, Ir(ppy) ₃ [factoris(2-phenylpyridine)iridium] which emits green light (see M.A. Baldo et al., Nature, Vol. 403, p. 750 (2000) above), and (btp) ₂ Ir(acac) {bis[2-(2'-benzo[4,5-α]thienyl)pyridinato-N,C ³ ]iridium(acetylacetonate)} which emits red light, and Ir(piq) ₃ [tris(1-phenylisoquinoline)iridium] which emits green light (see Adachi et al., Nature, Vol. 403, p. 750 (2000) above). al., Appl. Phys. Lett., 78 no. 11, 2001, 1622).

An example of a Pt complex is 2,3,7,8,12,13,17,18-octaethyl-21H,23H-phorphine platinum (PtOEP), which emits red light.
The phosphorescent materials may be small molecule or dendritic species, such as iridium core dendrimers, and derivatives thereof may also be suitably used.

In addition, when the light-emitting layer contains a phosphorescent material, it is preferable that the light-emitting layer contains a host material in addition to the phosphorescent material. The host material may be a low molecular weight compound or a high molecular weight compound, and dendrimers and the like can also be used.

Examples of low molecular weight compounds include CBP (4,4'-Bis(Carbazol-9-yl)-biphenyl), mCP (1,3-bis(9-carbazolyl)benzene), and CDBP (4,4'-Bis(Carbazol-9-yl)-2,2'-dimethylbiphenyl), while examples of high molecular weight compounds include polyvinylcarbazole, polyphenylene, and polyfluorene, and their derivatives can also be used.

The light-emitting layer may be formed by a deposition method or a coating method. Formation by a coating method is more preferable because the organic EL element can be produced inexpensively. To form the light-emitting layer by a coating method, a solution containing a phosphorescent material and, if necessary, a host material can be applied onto a desired substrate by a known method such as an inkjet method, a casting method, a dipping method, a printing method such as letterpress printing, intaglio printing, offset printing, lithographic printing, letterpress reverse offset printing, screen printing, or gravure printing, or a spin coating method.

(cathode)
The cathode material is preferably a metal or a metal alloy such as Li, Ca, Mg, Al, In, Cs, Ba, Mg--Ag, LiF, or CsF.

(anode)
The anode can also be made of a metal (e.g., Au) or other materials with metallic conductivity, such as an oxide (e.g., ITO), or a conductive polymer (e.g., a polythiophene-polystyrene sulfonate mixture (PEDOT:PSS)).

(Hole transport layer, hole injection layer)
It is preferable to use the organic layer as at least one of the hole transport layer and the hole injection layer. As described above, by using an organic layer containing an organic electronic material, these layers can be easily formed. In addition, for example, when the organic EL element has the organic layer as the hole transport layer and further has a hole injection layer, a known material may be used for the hole injection layer. In addition, when the organic EL element has the organic layer as the hole injection layer and further has a hole transport layer, a known material may be used for the hole transport layer. In addition, the organic EL element may have the organic layer as the hole transport layer and the hole injection layer.

When a material containing a triphenylamine structure is used in the hole injection layer, it is preferable to use the above-mentioned organic layer in the hole transport layer from the viewpoint of the energy level for the movement of holes. In particular, when the hole injection layer contains a polymerization initiator and the hole transport layer uses a branched polymer having a crosslinkable substituent as the charge transport polymer, the hole transport layer can be cured, and therefore it becomes possible to further coat an emitting layer composed of an organic electronic material, an ink composition, etc., on the upper layer.

(Electron transport layer, electron injection layer)
Examples of the electron transport layer and the electron injection layer include phenanthroline derivatives (e.g., 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)), bipyridine derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthalene perylene, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives (2-(4-biphenylyl)-5-(4-tert-butylphenyl-1,3,4-oxadiazole) (PBD)), aluminum complexes (e.g., Tris(8-hydroxyquinolinato)aluminum(III) (Alq3)), etc. Furthermore, in the above oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is replaced with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used.

(substrate)
The substrate usable for the organic EL element of this embodiment is not particularly limited in type, such as glass or plastic, and is not particularly limited as long as it is transparent, but glass, quartz, a light-transmitting resin film, etc. are preferably used. When a resin film is used, it is particularly preferable because it can impart flexibility to the organic EL element and function as a flexible substrate.

Examples of resin films include films whose main components are polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), etc.

In addition, when using a resin film, the resin film may be coated with an inorganic material such as silicon oxide or silicon nitride to prevent the transmission of water vapor, oxygen, etc.

(Emitting color)
The color of light emitted by the organic EL element of this embodiment is not particularly limited, but a white light emitting element is preferable because it can be used in various lighting fixtures such as home lighting, car lighting, and backlights for clocks and liquid crystal displays.

As for methods for forming white light-emitting elements, since it is currently difficult to produce white light emission from a single material, white light emission is achieved by using multiple light-emitting materials to simultaneously emit multiple light colors and mixing them. Combinations of multiple light-emitting colors are not particularly limited, but include those that contain three maximum emission wavelengths of blue, green, and red, and those that contain two maximum emission wavelengths that utilize the relationship between complementary colors such as blue and yellow, or yellow-green and orange. Furthermore, the emission color can be controlled by adjusting the type and amount of phosphorescent material.

[Display elements, lighting devices, display devices]
The display element of this embodiment is characterized by including the organic EL element. For example, by using the organic EL element as an element corresponding to each of red, green, and blue (RGB) pixels, a color display element can be obtained.
There are two methods for forming images: the simple matrix type, in which electrodes arranged in a matrix directly drive each organic EL element arranged on the panel, and the active matrix type, in which thin-film transistors are arranged in each element and driven. The former has a simple structure but is used to display characters and the like, as there is a limit to the number of vertical pixels. The latter requires a low driving voltage and small current, and produces bright, high-definition images, so is used for high-quality displays.

The lighting device of this embodiment is characterized by including the organic EL element. Furthermore, the display device of this embodiment is characterized by including a lighting device and a liquid crystal element as display means. The above-mentioned lighting device may be used as a backlight (white light source) and a display device using a liquid crystal element as display means, that is, a liquid crystal display device. This configuration is a configuration in which only the backlight of a known liquid crystal display device is replaced with the above-mentioned lighting device, and the liquid crystal element portion can be made using known technology.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

(Measurement of Number Average Molecular Weight and Weight Average Molecular Weight)
The number average molecular weight described below was measured by GPC (polystyrene equivalent) using tetrahydrofuran (THF) as an eluent under the following measurement conditions.
Pump: L-6050 Hitachi High-Technologies Corporation UV-Vis detector: L-3000 Hitachi High-Technologies Corporation Column: Gelpack® GL-A160S/GL-A150S Hitachi Chemical Co., Ltd. Eluent: THF (for HPLC, no stabilizer) Wako Pure Chemical Industries, Ltd. Flow rate: 1 mL/min
Column temperature: Room temperature Molecular weight standard: Standard polystyrene

<Synthesis of ionic compounds>
(Synthesis of ionic compound 1)
A fluororesin-coated magnetic stirrer was placed in a 200 mL wide-mouth flask, 1.8 g of N,N-dimethyl-N-octadecylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was weighed, 15 mL of acetone and 3 mL of pure water were added, and the mixture was stirred for 10 minutes. 2.2 g of a 10% by mass aqueous hydrochloric acid solution was dropped while stirring the obtained solution. Then, the solvent was reduced in pressure using a rotary evaporator until a white precipitate was precipitated. 46.5 g of a 10% by mass aqueous tetrakis(pentafluorophenylborate) sodium salt solution was added to the obtained solution (including the precipitate) while stirring, and the mixture was stirred for 30 minutes. Then, the organic layer was washed four times with pure water, and the precipitate was filtered off. The obtained precipitate was washed with pure water and then dried under vacuum. The dried solid was dissolved in methanol, and insoluble matter was removed using a 0.2 μm membrane filter, and the solution was poured into pure water and the white precipitate was filtered off. The obtained white precipitate was vacuum-dried to obtain ionic compound 1. The chemical structure of ionic compound 1 is shown in the following formula.

<Preparation of Pd catalyst>
In a glove box under a nitrogen atmosphere, 73.2 mg (80 μmol) of tris(dibenzylideneacetone)dipalladium was weighed out into a glass sample tube at room temperature, 15 mL of toluene was added, and the mixture was stirred for 30 minutes. Similarly, 129.6 mg (640 μmol) of tris(t-butyl)phosphine was weighed out into a glass sample tube, 5 mL of toluene was added, and the mixture was stirred for 5 minutes. These solutions were mixed and stirred at 80° C. for 2 hours, and the resulting solution was used as a catalyst after removing insoluble matter through a membrane filter with a pore size of 0.2 μm. All solvents were degassed with nitrogen bubbles for 30 minutes or more before use.

<Synthesis of charge transport material>
(Synthesis of Charge Transporting Polymer 1)
In a 200 mL three-neck round-bottom flask (made of glass), 5.15 g (10.0 mmol) of the following monomer 1, 1.93 g (4.0 mmol) of the following monomer 2, 1.08 g (4.0 mmol) of the following monomer 3, 1.17 g (4.0 mmol) of the following monomer 4, and 90 mL of toluene were added, and 7.8 mL of 1 mass% tetraethylammonium hydroxide aqueous solution and 14.2 mL of 3M potassium hydroxide aqueous solution were added. All solvents were used after degassing with nitrogen bubbles for 30 minutes or more. A reflux condenser and a nitrogen gas flow tube were attached to the flask containing the reaction solution, and the flask was immersed in an oil bath heated to 60 ° C. and stirred for 30 minutes. Subsequently, 2.0 mL of the above-prepared Pd catalyst solution was added, and the temperature of the oil bath was set to 120 ° C. to carry out the reaction. The reaction solution was heated and refluxed for 2 hours. All operations up to this point were carried out under a nitrogen stream.

After the reaction was completed, the organic layer was washed with water and poured into a methanol-water (9:1) mixed solution. The resulting precipitate was filtered by suction and washed with a methanol-water (9:1) mixed solution. The resulting precipitate was washed with ethyl acetate, and the eluted solid was vacuum dried. The dried solid was dissolved in toluene, and a metal adsorbent ("Triphenylphosphine, polymer-bound on styrene-divinylbenzene copolymer" manufactured by Strem Chemicals, 200 mg per 100 mg of precipitate) was added and stirred overnight. After stirring was completed, the metal adsorbent and insoluble matter were removed by filtration, and the solution was poured into methanol. The precipitate was filtered by suction and washed with methanol, and the solid was vacuum dried to obtain charge transport polymer 1. The number average molecular weight of charge transport polymer 1 was 18,000, and the weight average molecular weight was 55,000.

(Evaluation of Solvent Resistance)
An organic layer was formed using a charge transporting polymer and tris(pentafluorophenyl)borane (TPB) or an ionic compound, and the dissolution resistance was evaluated by measuring the remaining film ratio as follows. That is, an organic layer was formed in the process shown below, and the quartz plate with the formed organic layer was immersed in toluene and swung for 30 seconds. The remaining film ratio (%) of the organic layer was calculated using the following formula from the ratio of absorbance (Abs) at the absorption maximum (λmax) in the visible ultraviolet spectroscopy (UV-vis) spectrum before and after immersing the organic layer in toluene. The higher the remaining film ratio, the better the solvent resistance.

Film remaining rate (%) = (absorbance of organic layer after immersion in toluene / absorbance A of organic layer before immersion in toluene) x 100

Example 1
Charge transport polymer 1 (10.0 mg) and TPB (manufactured by Tokyo Chemical Industry Co., Ltd.) (0.10 mg) were dissolved in 0.9 mL of chlorobenzene to prepare an ink composition. The ink composition was spin-coated on a quartz plate at 3,000 rpm in the atmosphere. The spin-coated quartz plate was then placed in a nitrogen atmosphere glove box and heated on a nitrogen atmosphere hot plate at 200° C. for 30 minutes to carry out a curing reaction, forming an organic layer, and the remaining film ratio (%) of the organic layer was calculated.

Example 2
The residual film ratio was measured in the same manner as in Example 1, except that the curing reaction temperature was 175°C.

Example 3
The residual film rate was measured in the same manner as in Example 1, except that the curing reaction temperature was 150°C.

Example 4
The residual film rate was measured in the same manner as in Example 1, except that the curing reaction temperature was 125°C.

(Comparative Example 1)
The remaining film rate was measured in the same manner as in Example 1, except that ionic compound 1 was used instead of TPB.

(Comparative Example 2)
The remaining film ratio was measured in the same manner as in Example 1, except that an ink composition was used without using TPB (containing no TPB).

(Comparative Example 3)
The remaining film ratio was measured in the same manner as in Example 1, except that ionic compound 1 was used instead of TPB and the curing temperature was 175°C.

(Comparative Example 4)
The remaining film rate was measured in the same manner as in Example 1, except that ionic compound 1 was used instead of TPB and the curing temperature was 150°C.

(Comparative Example 5)
The remaining film rate was measured in the same manner as in Example 1, except that ionic compound 1 was used instead of TPB and the curing temperature was 125°C.

Below, Table 1 shows the results of Examples 1 to 4, and Table 2 shows the results of Comparative Examples 1 to 5.

It can be seen from Example 1 that the use of TPB improves the film remaining rate compared to Comparative Example 1, which uses ionic compound 1, and Comparative Example 2, which does not use TPB or ionic compound 1. Furthermore, as described above, even if the structural units constituting the charge transporting polymer are different, for example, by using the aryl boron compound of this embodiment as an organic electronics material, a good film remaining rate can be obtained, as in Example 1.
Furthermore, it can be seen from Examples 2 to 4 that by using TPB, a high residual film rate is maintained even when cured at a low temperature, compared to the cases where the ionic compounds of Comparative Examples 3 to 5 are used.

As described above, by using the aryl boron compound in this embodiment as an organic electronics material, it is possible to laminate good organic layers.

Reference Signs List 1 Light-emitting layer 2 Anode 3 Hole injection layer 4 Cathode 5 Electron injection layer 6 Hole transport layer 7 Electron transport layer 8 Substrate

Claims (18)

A compound having one or more structural units having charge transport properties in the molecule and having at least one crosslinkable substituent;
a boron compound having an aryl halide group ;
the compound having one or more structural units having charge transport properties and having at least one crosslinkable substituent in the molecule is a polymer,
The polymer has the following two structural moieties as a monovalent structural unit constituting an end portion of the polymer:
The organic electronic material , wherein the boron compound is a tri(halogenated aryl)borane .

(In the formula, * represents a bonding site with other structural units.) The organic electronic material of claim 1 , wherein the boron compound is tris(pentafluorophenyl)borane. 3. The organic electronic material according to claim 1, wherein the structural unit having a charge transport property comprises at least one structural unit selected from the group consisting of structural units having an aromatic amine structure, a carbazole structure, a thiophene structure, a furan structure, and a fluorene structure. 4. The organic electronic material according to claim 1, wherein the crosslinkable substituent comprises at least one selected from the group consisting of a carbon-carbon unsaturated bond, a cycloalkyl group having 3 to 5 carbon atoms, a cyclic ether group, a diketene group, an episulfide group, a lactone group, a lactam group, and a heterocycle having a heteroatom. 5. The organic electronic material according to claim 1 , wherein the crosslinkable substituent is a cyclic ether group, and the cyclic ether group includes at least one selected from the group consisting of an epoxy group and an oxetanyl group. The organic electronic material according to any one of claims 1 to 5 , wherein the polymer has a branched structure. The organic electronic material according to claim 6 , wherein the polymer has the following structural moiety as a trivalent structural unit constituting a branched structure:

(In the formula, * represents a bonding site with other structural units.) 8. The organic electronic material according to claim 1, wherein the polymer has the following structural moiety as a structural unit having charge transport properties:

(In the formula, * represents a bonding site with other structural units.) An ink composition comprising the organic electronic material according to any one of claims 1 to 8 and a solvent. An organic layer formed using the organic electronics material described in any one of claims 1 to 8 or the ink composition described in claim 9. An organic electronic device comprising at least one organic layer according to claim 10. An organic electroluminescence device comprising at least one organic layer according to claim 10. The organic electroluminescence element according to claim 12, further comprising a flexible substrate. The organic electroluminescence element according to claim 12, further comprising a resin film substrate. A display element comprising an organic electroluminescence element according to any one of claims 12 to 14. A lighting device comprising an organic electroluminescence element according to any one of claims 12 to 14. A display device comprising an organic electroluminescence element according to any one of claims 12 to 14. A display device comprising the lighting device according to claim 16 and a liquid crystal element as a display means.

Images