Organic electronics material and organic electronics element

Abstract

The present disclosure relates to an organic electronics material that contains a branched charge-transporting polymer including: a divalent structural unit having a fluorene structure that has a substituent; at least one structural unit selected from the group consisting of trivalent structural units having a triphenylamine structure and trivalent structural units having a carbazole structure; and a monovalent structural unit having a polymerizable functional group.

Description

Organic electronic materials and organic electronic elements

[0001] FIELD OF THE INVENTION The present invention relates to an organic electronic material, an organic electronic element, an organic electroluminescence element (organic EL element), and an organic photoelectric conversion element.

[0002] Organic electronics devices are devices that use organic materials for electrical operation and are expected to offer advantages such as energy saving, low cost, and flexibility. Organic electronic devices may have multiple organic layers to improve device characteristics.

[0003] As a method for forming multiple organic layers by a wet process, a method using a compound having a polymerizable group is known. Patent Document 1 describes an organic electroluminescent element having a cathode and an anode on a substrate and multiple organic layers therebetween, characterized in that at least one of the organic layers is a layer containing organic molecules having 10 or less repeating units obtained by coating and polymerizing a compound having at least one polymerizable group.

[0004] Japanese Patent Application Laid-Open No. 2006-279007

[0005] An object of an embodiment of the present invention is to provide an organic electronic material capable of forming an organic layer having excellent solvent resistance.An object of another embodiment of the present invention is to provide an organic electronic device, an organic electroluminescence device, and an organic photoelectric conversion device including an organic layer having excellent solvent resistance.

[0006] The present invention includes the following embodiments. The present invention is not limited to the following embodiments. One embodiment relates to an organic electronic material containing a branched charge transport polymer including at least one structural unit selected from the group consisting of a divalent structural unit having a fluorene structure with a substituent, a trivalent structural unit having a triphenylamine structure, and a trivalent structural unit having a carbazole structure, and a monovalent structural unit having a polymerizable functional group. Another embodiment relates to an organic electronic device including an organic layer formed using the organic electronic material. Another embodiment relates to an organic electroluminescence device including at least one layer selected from the group consisting of a hole injection layer formed using the organic electronic material and a hole transport layer formed using the organic electronic material. Another embodiment relates to an organic photoelectric conversion device including an organic layer formed using the organic electronic material.

[0007] According to an embodiment of the present invention, an organic electronic material capable of forming an organic layer having excellent solvent resistance can be provided. Also, according to another embodiment of the present invention, an organic electronic device, an organic electroluminescence device, and an organic photoelectric conversion device including an organic layer having excellent solvent resistance can be provided.

[0008] The following describes embodiments of the present invention. The present invention is not limited to the following embodiments. The following embodiments can be implemented alone or in combination. Combinations of multiple embodiments are also included in the present invention. In this disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. The upper or lower limit of a numerical range described in this disclosure may be replaced with a value shown in an example. A stepped numerical range may be created by selecting a numerical value from the upper limit and lower limit numerical values ​​described in stages in this disclosure. The upper and lower limit numerical values ​​described in this disclosure may be replaced with a value shown in an example. In this disclosure, unless otherwise specified, "comprising A or B" means that either A or B may be included, or both may be included. In this disclosure, each component may contain multiple corresponding substances. When a composition contains multiple substances corresponding to each component, the content or amount of each component refers to the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, each structure in the polymer may contain multiple corresponding structures. When a polymer contains multiple structures corresponding to each structure, the content or amount of each structure refers to the total content or amount of the multiple structures present in the polymer, unless otherwise specified. In the present disclosure, "layer" includes continuous and discontinuous layers. The thickness of a "layer" may be uniform or non-uniform. The outer edges of a "layer" in the plane direction and the outer edges in the thickness direction may be clear or unclear, respectively. The same applies to a "film."

[0009] <Organic Electronic Material> In an embodiment of the present invention, the organic electronic material contains a branched charge-transporting polymer including a divalent structural unit having a fluorene structure having a substituent, at least one structural unit selected from the group consisting of a trivalent structural unit having a triphenylamine structure and a trivalent structural unit having a carbazole structure, and a monovalent structural unit having a polymerizable functional group. The organic electronic material may further contain optional components such as a dopant and a polymerization initiator.

[0010] In the present disclosure, a divalent structural unit having a substituted fluorene structure, a trivalent structural unit having a triphenylamine structure, a trivalent structural unit having a carbazole structure, and a monovalent structural unit having a polymerizable functional group may be referred to as a "fluorene structural unit A," a "triphenylamine structural unit B," a "carbazole structural unit B," and a "polymerizable structural unit C," respectively.

[0011] [Charge-transporting polymer] The charge-transporting polymer contains at least a fluorene structural unit A, at least one structural unit selected from the group consisting of a triphenylamine structural unit B and a carbazole structural unit B, and a polymerizable structural unit C. The charge-transporting polymer is a branched polymer. In the charge-transporting polymer, the at least one structural unit selected from the group consisting of a triphenylamine structural unit B and a carbazole structural unit B is a structural unit that becomes a branch of the polymer chain.

[0012] The charge transporting polymer may have any structural unit other than the fluorene structural unit A, the triphenylamine structural unit B, the carbazole structural unit B, and the polymerizable structural unit C. For example, the charge transporting polymer may further include a divalent structural unit having a triphenylamine structure having a fluoro group. The charge transporting polymer may further include a monovalent structural unit having a linear alkyl group having 4 to 18 carbon atoms. In the present disclosure, the divalent structural unit having a triphenylamine structure having a fluoro group and the monovalent structural unit having a linear alkyl group having 4 to 18 carbon atoms may be referred to as the "triphenylamine structural unit A" and the "alkyl structural unit D," respectively.

[0013] (Fluorene structural unit A) The fluorene structural unit A is a divalent structural unit having a fluorene structure with a substituent. The organic layer formed using the charge transport polymer has excellent solvent resistance. It is presumed that the fluorene structure contained in the fluorene structural unit A is oriented and present in the organic layer, making the organic layer less soluble in solvents and improving solvent resistance. However, the present invention is not limited by this presumption.

[0014] The fluorene structure having a substituent may be, for example, a structure in which one or two hydrogen atoms bonded to the carbon atom at position 9 of the fluorene ring are substituted with a substituent. When the fluorene structure includes two or more substituents, the two or more substituents may be the same or different. Examples of the substituent include an alkyl group, an aryl group, a halogen group, a halogen-substituted alkyl group, a nitro group, a cyano group, a sulfonic acid group, a sulfoxide group, an amino group, a hydroxy group, an alkoxy group, a thio group, an alkylthio group, a trialkylsilyl group, and the like. The alkyl group included in the substituent may be linear, branched, or cyclic. The substituent may be, for example, an alkyl group or an aryl group.

[0015] When the substituent is a linear alkyl group, better solvent resistance tends to be obtained. From the viewpoint of solvent resistance and film-forming ability, the substituent is preferably a linear alkyl group having 4 to 18 carbon atoms, more preferably a linear alkyl group having 6 to 10 carbon atoms. When the fluorene structure has a linear alkyl group, it is presumed that the entanglement of the alkyl groups further improves the solvent resistance of the organic layer. Furthermore, when the fluorene structure has a linear alkyl group, it is presumed that the solubility of the charge transport polymer in solvents is improved when forming an organic layer by a wet process, thereby improving film-forming ability. However, the present invention is not limited by these presumptions.

[0016] If an organic layer has excellent solvent resistance, the lower layer can be prevented from dissolving in a solvent when another organic layer (upper layer) is formed on the lower organic layer by a wet process. If dissolution of the lower layer is suppressed, mixing of the materials of the upper layer and the lower organic layer can be prevented when the upper layer is formed, and multiple adjacent organic layers can be formed in good condition.

[0017] The fluorene structural unit A may, for example, be a divalent structural unit represented by the following formula (A-1). (In the formula, R ａ represents a substituent, R ｂ represents a hydrogen atom or a substituent, and * represents the bonding position to other structural units.

[0018] The divalent structural unit represented by formula (A-1) may be, for example, a structural unit represented by any of the following formulas: (In the formula, R ａ represents a substituent, R ｂ represents a hydrogen atom or a substituent, and * represents the bonding position to other structural units.

[0019] In the formula (A-1) and the above formulas, from the viewpoint of improving solvent resistance, R ａ and R ｂ may be an alkyl group, preferably a linear alkyl group having 4 to 18 carbon atoms, more preferably a linear alkyl group having 6 to 10 carbon atoms.

[0020] (Triphenylamine structural unit B and carbazole structural unit B) The triphenylamine structural unit B is a trivalent structural unit having a triphenylamine structure. The benzene ring contained in the triphenylamine structure may be substituted or unsubstituted. The carbazole structural unit B is a trivalent structural unit having a carbazole structure. The benzene ring contained in the carbazole structure may be substituted or unsubstituted. When the benzene ring contained in the triphenylamine structural unit B and the carbazole structural unit B has a substituent, examples of the substituent are as exemplified for the fluorene structural unit A.

[0021] In the charge transporting polymer, the triphenylamine structural unit B and the carbazole structural unit B form branched portions of the polymer chain, making the charge transporting polymer a branched polymer. A branched polymer has three or more terminal portions per molecule. When the charge transporting polymer is a branched polymer, the number of polymerizable structural units C per molecule can be increased, and the solvent resistance of the charge transporting polymer can be improved. Furthermore, when the charge transporting polymer is a branched polymer, the molecular weight can be easily increased and the polymer tends to exhibit good solubility during film formation.

[0022] The triphenylamine structural unit B includes, for example, a trivalent structural unit represented by the following formula (B-1). (In the formula, * represents the bonding position to other structural units, and the benzene ring may have a substituent at a substitutable position.)

[0023] The trivalent structural unit represented by formula (B-1) may be, for example, a structural unit represented by the following formula: (In the formula, * represents the bonding position to other structural units, and the benzene ring may have a substituent at a substitutable position.)

[0024] The carbazole structural unit B may be, for example, a trivalent structural unit represented by the following formula (B-2).

[0025] The trivalent structural unit represented by formula (B-2) may be, for example, a structural unit represented by any of the following formulas: (In the formula, * represents the bonding position to other structural units, and the benzene ring may have a substituent at a substitutable position.)

[0026] (Polymerizable structural unit C) The polymerizable structural unit C is a monovalent structural unit having a polymerizable functional group. The polymerizable structural unit is contained at the terminal of the polymer chain in the charge transport polymer. Since the charge transport polymer contains the polymerizable structural unit C, the charge transport polymer has curability, and the resulting organic layer exhibits solvent resistance.

[0027] Examples of polymerizable functional groups include groups having a substituted or unsubstituted carbon-carbon multiple bond (e.g., vinyl group, styryl group, allyl group, butenyl group, ethynyl group, acryloyl group, acryloyloxy group, acryloylamino group, methacryloyl group, methacryloyloxy group, methacryloylamino group, vinyloxy group, vinylamino group), substituted or unsubstituted cyclic alkyl group (e.g., cyclopropyl group, benzocyclobutenyl group, cyclobutyl group), substituted or unsubstituted groups having a cyclic ether structure (e.g., epoxy group (oxiranyl group), oxetane group (oxetanyl group)), and fused ring groups of a substituted or unsubstituted cyclic alkyl group and a benzene ring (benzocyclobutene group). When these groups are substituted, the substituent is not particularly limited, and examples include linear, branched, and cyclic alkyl groups. The alkyl group more preferably has 1 to 10 carbon atoms, and even more preferably has 1 to 4 carbon atoms.

[0028] From the viewpoint of curability, for example, the polymerizable structural unit C comprises at least one selected from the group consisting of a structural unit having a vinyl group, a structural unit having an oxetane group, and a structural unit having a benzocyclobutene group. For example, when the organic electronic material is used to form a layer adjacent to an active layer such as a light-emitting layer or a photoelectric conversion layer, from the viewpoint of device characteristics, the polymerizable structural unit C is preferably a structural unit having a vinyl group, a structural unit having a benzocyclobutene group, or both of these structural units. For example, when the organic electronic material is used to form a layer other than the adjacent layer, from the viewpoint of curability, the polymerizable structural unit C is preferably a structural unit having an oxetane group. Structural units having an oxetane group and structural units having a benzocyclobutene group have particularly good curability, and when the polymerizable structural unit C comprises at least one of these structural units, the curing reaction of the charge transport polymer proceeds sufficiently even without using a polymerization initiator, and an organic layer having excellent solvent resistance tends to be obtained.

[0029] When the charge-transporting polymer contains a structural unit having a vinyl group and a structural unit having a benzocyclobutene group, the content of the structural unit having a vinyl group and the content of the structural unit having a benzocyclobutene group, relative to the total content of both being 100 mol %, are, for example, 10 to 90 mol %:90 to 10 mol %, 30 to 70 mol %:70 to 30 mol %, or 40 to 60 mol %:60 to 40 mol %,

[0030] Examples of the polymerizable structural unit C include a monovalent structural unit represented by the following (C-1), a monovalent structural unit represented by the following (C-2), and a monovalent structural unit represented by the following (C-3). (In the formula, Vinyl represents a substituted or unsubstituted vinyl group, L represents a direct bond or a linking group, and * represents the bonding position to other structural units.) (In the formula, OXT represents a substituted or unsubstituted oxetane group, L represents a direct bond or a linking group, and * represents the bonding position to another structural unit.) (In the formula, * represents the bonding position to other structural units.)

[0031] Examples of the linking group include an alkylene group, a sulfinyl group (*-SO-*), a sulfonyl group (*-SO ２ -*), imino group (*-NH-*), oxy group (*-O-*), carbonyl group (*-CO-*), and groups containing two or more selected from these. The alkylene group has, for example, 1 to 18 carbon atoms. The alkylene group may be linear, branched, or cyclic, and is preferably a linear alkylene group. In formula (C-1), when L is a direct bond, the vinyl group is directly bonded to the benzene ring. That is, the structural unit represented by formula (C-1) is *-Ph-Vinyl (Ph is a benzene ring). In formula (C-2), when L is a direct bond, the oxetane group is directly bonded to the benzene ring. That is, the structural unit represented by formula (C-2) is *-Ph-OXT (Ph is a benzene ring).

[0032] When L is a direct bond, the organic electronic device tends to exhibit good life characteristics. When L is a linear alkylene group having 4 to 18 carbon atoms or a group containing a linear alkylene group having 4 to 18 carbon atoms and an oxy group, the charge transporting polymer tends to exhibit good solubility in a solvent in a wet process.

[0033] (Triphenylamine structural unit A) The triphenylamine structural unit A is a divalent structural unit having a triphenylamine structure having a fluoro group. When the charge transporting polymer contains the triphenylamine structural unit A, the HOMO energy level of the organic layer tends to be adjusted lower. When the organic electronic material is used as a hole transport layer material, the charge transporting polymer preferably contains the triphenylamine structural unit A. The benzene ring contained in the triphenylamine structure may be substituted or unsubstituted. When the benzene ring has a substituent, examples of the substituent are as exemplified for the fluorene structural unit A.

[0034] An example of the triphenylamine structural unit A is a monovalent structural unit represented by the following formula (A-2). (In the formula, each R independently represents a hydrogen atom or a substituent, at least one R is a fluoro group, and * represents the bonding position to another structural unit.)

[0035] In formula (A-2), one to three R may be fluoro groups and the remaining R may be hydrogen atoms, preferably one R may be fluoro group and the remaining R may be hydrogen atoms.

[0036] (Alkyl Structural Unit D) The alkyl structural unit D is a monovalent structural unit having a linear alkyl group having 4 to 18 carbon atoms. When the charge transporting polymer contains the alkyl structural unit D, the solubility of the charge transporting polymer in a solvent tends to be improved in a wet process. The linear alkyl group preferably has 6 to 10 carbon atoms.

[0037] Examples of the alkyl structural unit D include a monovalent structural unit represented by the following formula (D). (In the formula, n represents an integer of 3 to 17, and * represents the bonding position to other structural units.)

[0038] In formula (D), n may be 5 to 9 from the viewpoint of solvent resistance and film-forming properties.

[0039] (Other structural units) The charge transporting polymer may further contain other optional structural units different from the above-mentioned structural units. The other optional structural units include, for example, a substituted or unsubstituted aromatic amine structure, a substituted or unsubstituted carbazole structure, a substituted or unsubstituted thiophene structure, a substituted or unsubstituted fluorene structure, a substituted or unsubstituted benzene structure, a substituted or unsubstituted biphenyl structure, a substituted or unsubstituted terphenyl structure, a substituted or unsubstituted naphthalene structure, a substituted or unsubstituted anthracene structure, a substituted or unsubstituted tetracene structure, a substituted or unsubstituted phenanthrene structure, a substituted or unsubstituted dihydrophenanthrene structure, a substituted or unsubstituted pyridine structure, a substituted or unsubstituted pyrazine structure, a substituted or unsubstituted quinoline structure, a substituted or unsubstituted isoquinoline structure, a substituted or unsubstituted quinoxaline structure, a substituted or an unsubstituted acridine structure, a substituted or unsubstituted diazaphenanthrene structure, a substituted or unsubstituted furan structure, a substituted or unsubstituted pyrrole structure, a substituted or unsubstituted oxazole structure, a substituted or unsubstituted oxadiazole structure, a substituted or unsubstituted thiazole structure, a substituted or unsubstituted thiadiazole structure, a substituted or unsubstituted triazole structure, a substituted or unsubstituted benzothiophene structure, a substituted or unsubstituted benzoxazole structure, a substituted or unsubstituted benzoxadiazole structure, a substituted or unsubstituted benzothiazole structure, a substituted or unsubstituted benzothiadiazole structure, a substituted or unsubstituted benzotriazole structure, and structures containing one or more of these.

[0040] The optional structural unit may be monovalent or higher, preferably monovalent to hexavalent, and more preferably monovalent to tetravalent. Examples of the substituent contained in the optional structural unit are as exemplified for the fluorene structural unit A.

[0041] (Content of Each Structural Unit) In some embodiments, the charge transporting polymer contains 5 to 60 mol %, 10 to 55 mol %, or 15 to 50 mol % of the fluorene structural unit A based on all structural units, from the viewpoint of solvent resistance of the organic layer. The content of the fluorene structural unit A may be, for example, 35 mol % or less, 30 mol % or less, or 25 mol % or less.

[0042] In some embodiments, the charge transporting polymer comprises, based on all structural units, 30 to 60 mol % of fluorene structural units A, 5 to 30 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, and 20 to 50 mol % of polymerizable structural units C. The charge transporting polymer may comprise, based on all structural units, 35 to 55 mol % of fluorene structural units A, 10 to 25 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, and 25 to 45 mol % of polymerizable structural units C, or 40 to 50 mol % of fluorene structural units A, 13 to 23 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, and 30 to 40 mol % of polymerizable structural units C. The content of any structural unit other than the above structural units may be, for example, 10 mol % or less, 5 mol % or less, or 0 mol %. The organic electronic materials according to these embodiments are suitable as hole injection layer materials.

[0043] When the content of the fluorene structural unit A is 30 mol% or more, the solvent resistance of the organic layer tends to be further improved. When the content of at least one structural unit selected from the group consisting of the triphenylamine structural unit B and the carbazole structural unit B is 5 mol% or more, the molecular weight of the charge transport polymer can be increased and the solubility during film formation tends to be improved. When the content of the polymerizable structural unit C is 20 mol% or more, the curing reaction of the charge transport polymer easily proceeds, and the solvent resistance of the organic layer tends to be further improved.

[0044] In some embodiments, the charge transporting polymer comprises, based on all structural units, 5 to 60 mol % of fluorene structural units A, 5 to 30 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 1 to 30 mol % of polymerizable structural units C, and 10 to 40 mol % of alkyl structural units D. The charge transporting polymer may comprise, based on all structural units, 10 to 55 mol % of fluorene structural units A, 10 to 25 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 3 to 20 mol % of polymerizable structural units C, and 15 to 35 mol % of alkyl structural units D; or, based on all structural units, 15 to 50 mol % of fluorene structural units A, 13 to 23 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 5 to 15 mol % of polymerizable structural units C, and 20 to 30 mol % of alkyl structural units D. The content of any structural units other than the above structural units may be, for example, 10 mol % or less, 5 mol % or less, or 0 mol %. The organic electronic materials according to these embodiments are suitable as hole transport layer materials.

[0045] In some embodiments, the charge transporting polymer comprises, based on all structural units, 5 to 35 mol % of fluorene structural units A, 10 to 40 mol % of the triphenylamine structural units A, 5 to 30 mol % of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 1 to 30 mol % of polymerizable structural units C, and 10 to 40 mol % of alkyl structural units D. The charge transporting polymer may comprise, based on all structural units, 10 to 30 mol% of fluorene structural units A, 15 to 35 mol% of the triphenylamine structural units A, 10 to 25 mol% of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 3 to 20 mol% of polymerizable structural units C, and 15 to 35 mol% of alkyl structural units D; or, based on all structural units, 15 to 25 mol% of fluorene structural units A, 20 to 30 mol% of the triphenylamine structural units A, 13 to 23 mol% of at least one structural unit selected from the group consisting of triphenylamine structural units B and carbazole structural units B, 5 to 15 mol% of polymerizable structural units C, and 20 to 30 mol% of alkyl structural units D. The content of any structural units other than the structural units may be, for example, 10 mol% or less, 5 mol% or less, or 0 mol%. The organic electronic materials according to these embodiments are suitable as hole transport layer materials.

[0046] When the content of the fluorene structural unit A is 5 mol% or more, the solvent resistance of the organic layer tends to be further improved. When the content of at least one structural unit selected from the group consisting of the triphenylamine structural unit B and the carbazole structural unit B is 5 mol% or more, the molecular weight of the charge transport polymer can be increased, and the solubility during film formation tends to be improved. When the content of the polymerizable structural unit C is 1 mol% or more, the curing reaction of the charge transport polymer tends to proceed easily, and the solvent resistance of the organic layer tends to be further improved. When the content of the triphenylamine structural unit A is 10 mol% or more, a low HOMO energy level tends to be easily obtained. From the viewpoint of the solvent resistance of the organic layer and the solubility of the charge transport polymer, the content of the triphenylamine structural unit A may be 40 mol% or less. When the content of the alkyl structural unit D is 10 mol% or more, the solubility of the charge transport polymer tends to be improved.

[0047] The content of the structural unit can be determined using the amount of monomer used to synthesize the charge transport polymer, which corresponds to each structural unit. １ The average value can be calculated using the integral values ​​of the spectra derived from each structural unit in the H NMR spectrum. When the amount used is known, it is preferable to use the value calculated using the amount used, since this is simple.

[0048] (Number Average Molecular Weight) The number average molecular weight of the charge transporting polymer can be adjusted appropriately taking into consideration the solubility of the charge transporting polymer in a solvent, film-forming properties, etc. The number average molecular weight may be 8,000 or more, 10,000 or more, or 15,000 or more from the viewpoint of excellent solvent resistance and charge transport properties. The number average molecular weight may be 50,000 or less, 30,000 or less, or 20,000 or less from the viewpoint of maintaining good solubility of the charge transporting polymer in a solvent and facilitating preparation of a liquid composition.

[0049] (Weight-average molecular weight) The weight-average molecular weight of the charge-transporting polymer can be adjusted appropriately taking into consideration the solubility of the charge-transporting polymer in a solvent, film-forming properties, etc. The weight-average molecular weight may be 50,000 or more, 100,000 or more, or 150,000 or more from the viewpoint of excellent solvent resistance and charge transport properties. The weight-average molecular weight may be 500,000 or less, 300,000 or less, or 200,000 or less from the viewpoint of maintaining good solubility of the charge-transporting polymer in a solvent and facilitating preparation of a liquid composition.

[0050] The number average molecular weight and the weight average molecular weight can be measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. Measurement conditions include, for example, the conditions described in the Examples.

[0051] (Method for producing charge transport polymer) The charge transport polymer can be produced using at least one monomer selected from the group consisting of a bifunctional monomer having a fluorene structural unit A, a trifunctional monomer having a triphenylamine structural unit B, and a trifunctional monomer having a carbazole structural unit B, a monofunctional monomer having a polymerizable structural unit C, and, if necessary, an optional monomer. Examples of the optional monomer include a bifunctional monomer having a triphenylamine structural unit A and a monofunctional monomer having an alkyl structural unit D. In the method for producing the charge transport polymer, for example, the monomers are polymerized by a coupling reaction.

[0052] Coupling reactions that can be used include known reactions such as Suzuki coupling, Negishi coupling, Sonogashira coupling, Stille coupling, and Buchwald-Hartwig coupling. Suzuki coupling involves, for example, a cross-coupling reaction between an aromatic boronic acid compound or an aromatic boronic acid ester compound and an aromatic halogen compound using a Pd catalyst. Suzuki coupling allows for the easy production of charge-transporting polymers by bonding desired aromatic rings together. Examples of reactive functional groups include a bromo group, a boronic acid group, and a boronic acid ester group.

[0053] In Suzuki coupling, catalysts used include, for example, Pd compounds such as Pd(0) compounds and Pd(II) compounds, Ni compounds, and Ru compounds. It is also possible to use catalyst species generated by mixing precursors such as tris(dibenzylideneacetone)dipalladium(0) and palladium(II) acetate with a phosphine ligand in the reaction system. Examples of reaction solvents include organic solvents, and preferred are mixed solvents of water and organic solvents. Examples of organic solvents include aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, and diphenylmethane; and tetrahydrofuran, acetone, acetonitrile, and N,N-dimethylformamide. In the reaction, a base such as an alkali metal carbonate, an alkali metal hydroxide, an alkali metal phosphate, or a water-soluble organic base can be used. The reaction can also be promoted by adding a phase transfer catalyst.

[0054] [Dopant] The organic electronic material may contain any additive, for example, a dopant. The dopant is not particularly limited as long as it can exhibit a doping effect when added to the organic electronic material and improve the charge transport property. It is preferable to perform p-type doping to improve hole transport property, and n-type doping to improve electron transport property.

[0055] The dopant used in p-type doping is an electron-accepting compound, and examples thereof include Lewis acids, protonic acids, transition metal compounds, ionic compounds, halogen compounds, and π-conjugated compounds. The organic electronic material may contain an ionic compound. Among ionic compounds, onium salts are particularly preferred. The onium salt may be a compound consisting of a cation containing an onium ion such as carbonium, sulfonium, iodonium, or ammonium, and a counter anion.

[0056] The dopant used for n-type doping is an electron-donating compound, for example, alkali metals such as Li and Cs; alkaline earth metals such as Mg and Ca; LiF, Cs ２ CO ３ and the like; metal complexes; electron-donating organic compounds; and the like.

[0057] In order to improve the solvent resistance of the organic layer, a compound capable of acting as a polymerization initiator for the polymerizable functional group may be used as a dopant. Alternatively, when the charge transport polymer contains a polymerizable structural unit C having excellent curability, an organic layer having excellent solvent resistance can be formed without using a polymerization initiator. The organic layer adjacent to an active layer such as a light-emitting layer or a photoelectric conversion layer may be a layer formed without using a polymerization initiator, taking into consideration the influence on the active layer.

[0058] [Other Optional Components] The organic electronic material may further contain a charge-transporting low-molecular-weight compound, other polymers, and the like.

[0059] [Content] The organic electronic material may contain one type of the charge transport polymer alone or a combination of two or more types. From the viewpoint of obtaining good charge transport properties, the content of the charge transport polymer in the organic electronic material is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the organic electronic material (excluding the mass of the solvent if the material contains a solvent). The upper limit of the content of the charge transport polymer is not particularly limited, and it can be 100% by mass. Taking into account the presence of additives such as dopants, the content of the charge transport polymer may be, for example, 95% by mass or less or 90% by mass or less.

[0060] When the organic electronic material contains a dopant, the organic electronic material may contain one dopant alone or two or more dopants in combination. When the organic electronic material contains a dopant, the content of the dopant 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, based on the total mass of the organic electronic material (excluding the mass of the solvent if the material contains a solvent), from the viewpoint of improving the charge transport property of the organic electronic material. Furthermore, from the viewpoint of maintaining good film-forming properties, the content of the dopant is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the total mass of the organic electronic material.

[0061] <Liquid Composition> In an embodiment of the present invention, the organic electronic material may be a liquid composition containing a solvent. The liquid composition containing a solvent makes it possible to easily form an organic layer by a wet process. The liquid composition can be used as an ink composition.

[0062] [Solvent] Any solvent can be used as the solvent, such as water, an organic solvent, or a mixed solvent thereof. Examples of the organic solvent include alcohols such as methanol, ethanol, and isopropyl alcohol; alkanes such as pentane, hexane, and octane; cyclic alkanes such as cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, and diphenylmethane; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate, and cyclopentyl methyl ether; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole. Examples of the solvent include aromatic ethers such as ethanol, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, 2-methylcyclopentanone, and 2-methylcyclohexanone; aliphatic cyclic ketones such as cyclobutanone, cyclopentanone, cyclohexanone, and 2-methylcyclohexanone; 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; aromatic halides such as chlorobenzene, o-dichlorobenzene, and 1-chloronaphthalene; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; dimethyl sulfoxide, tetrahydrofuran, acetone, chloroform, and methylene chloride. The liquid composition may contain one solvent alone, or two or more solvents.

[0063] [Additives] The liquid composition may further contain additives as optional components, such as polymerization inhibitors, stabilizers, thickeners, gelling agents, flame retardants, antioxidants, anti-reducing agents, oxidizing agents, reducing agents, surface modifiers, emulsifiers, antifoaming agents, dispersants, surfactants, etc.

[0064] [Content] The content of the solvent in the liquid composition can be determined in consideration of application to various coating methods.For example, the content of the solvent is preferably such that the ratio of the charge transport polymer to the solvent is 0.1% by mass or more, more preferably such that the ratio is 0.2% by mass or more, and even more preferably such that the ratio is 0.5% by mass or more.Furthermore, the content of the solvent is preferably such that the ratio of the charge transport polymer to the solvent is 20% by mass or less, more preferably such that the ratio is 15% by mass or less, and even more preferably such that the ratio is 10% by mass or less.

[0065] <Organic Layer> In an embodiment of the present invention, the organic layer is a layer formed using the organic electronics material. The organic layer exhibits good solvent resistance. By using a liquid composition, an organic layer can be formed easily and satisfactorily by a coating method. Examples of the coating method include known methods such as spin coating; casting; immersion; plate-based printing methods such as relief printing, intaglio printing, offset printing, lithographic printing, relief reverse offset printing, screen printing, and gravure printing; and plateless printing methods such as inkjet printing.

[0066] When the organic layer is formed by a coating method, the layer containing the charge-transporting polymer obtained after coating may be dried using a hot plate or an oven to remove the solvent. By applying heat, light, or both to the layer containing the charge-transporting polymer, the charge-transporting polymer can be cured to form a solvent-resistant organic layer.

[0067] 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 charge transport efficiency, and 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 electrical resistance.

[0068] <Organic Electronic Element> In an embodiment of the present invention, an organic electronic element has at least the organic layer. Examples of the organic electronic 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 electronic element preferably has a structure in which an organic layer is disposed between at least a pair of electrodes.

[0069] <Organic Electroluminescence Element (Organic EL Element)> In an embodiment of the present invention, the organic EL element has at least the organic layer described above. The organic EL element typically includes an emitting layer, an anode, a cathode, and a substrate, and, if necessary, functional layers such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer. Each layer may be formed by a vapor deposition method or a coating method. Known materials can be used to form each layer. For known materials, see, for example, WO 2010 / 140553. The organic EL element preferably includes an organic layer as an emitting layer or a functional layer, more preferably as a functional layer, and even more preferably as at least one of a hole injection layer and a hole transport layer. For the structure and manufacturing method of the organic EL, see, for example, WO 2010 / 140553.

[0070] The organic layer formed using the organic electronic material is preferably used as at least one of a hole injection layer and a hole transport layer, and more preferably as at least a hole injection layer. By using a liquid composition as the organic electronic material, these layers can be easily formed.

[0071] When an organic EL element has an organic layer formed using the organic electronic material as a hole transport layer and further has a hole injection layer, a known material can be used for the hole injection layer. When an organic EL element has an organic layer formed using the organic electronic material as a hole injection layer and further has a hole transport layer, a known material can be used for the hole transport layer. It is also preferable to use an organic electronic material for both the hole injection layer and the hole transport layer.

[0072] <Display element, lighting device, display device> In an embodiment of the present invention, a display element includes the organic EL element. For example, a color display element can be obtained by using organic EL elements as elements corresponding to red, green, and blue (RGB) pixels. Image formation methods include a simple matrix type in which individual organic EL elements arranged on a panel are directly driven by electrodes arranged in a matrix, and an active matrix type in which each element is driven by a thin-film transistor.

[0073] The lighting device includes the organic EL element. The display device includes the lighting device and a liquid crystal element as a display means. For example, the display device can be a display device that uses the lighting device as a backlight and a known liquid crystal element as a display means, i.e., a liquid crystal display device.

[0074] <Organic Photoelectric Conversion Element> In an embodiment of the present invention, the organic photoelectric conversion element includes at least the organic layer. Organic photoelectric conversion elements include organic solar cells, organic image sensors, and the like. The organic photoelectric conversion element includes, for example, a photoelectric conversion layer, an electrode, and a substrate. Furthermore, for the purpose of improving conversion efficiency or stability in air, other layers such as a buffer layer and an electron transport layer may be included. The organic photoelectric conversion element includes at least the organic layer, and the organic layer can be used as a photoelectric conversion layer and a buffer layer, and is preferably used as a buffer layer. Therefore, an example of an organic photoelectric conversion element includes an anode, an organic layer as a buffer layer, a photoelectric conversion layer, and a cathode in this order, and may further include any layer between these layers.

[0075] Any material can be used for the photoelectric conversion layer as long as it absorbs light, causes charge separation, and generates an electromotive force. The material for the photoelectric conversion layer may be, for example, a mixture of a p-type organic semiconductor and an n-type organic semiconductor blended together from the viewpoint of conversion efficiency. Examples of p-type organic semiconductors include polymers or oligomers such as oligothiophene, polyalkylthiophene, poly(3-hexylthiophene) (P3HT), and polyphenylene vinylene (PPV); porphyrin, phthalocyanine, copper phthalocyanine; and derivatives thereof. Examples of n-type organic semiconductors include CN-poly(phenylene vinylene) (CN-PPV), MEH-CN-PPV, and -CF ３ -CN group or -CF of substituted polymers, etc. ３ group-containing polymers or oligomers; polymers or oligomers such as poly(fluorene) derivatives and fluorene-benzothiadiazole copolymers; fullerene (C 60 ), naphthalenetetracarboxylic anhydride (NTCDA), perylenetetracarboxylic anhydride (PTCDA), quinacridone; and derivatives thereof. From the viewpoints of conversion efficiency, flexibility, productivity, and the like, the material for the photoelectric conversion layer may be a material containing a perovskite compound.

[0076] The method for forming the photoelectric conversion layer is not particularly limited, and may be formed by a vapor deposition method or a coating method. When formed by a coating method, the organic photoelectric conversion element can be manufactured inexpensively, which is more preferable. As a method for forming by a coating method, the method described in the method for forming the organic layer can be used.

[0077] The organic photoelectric conversion element may have the buffer layer in addition to the photoelectric conversion layer, and may further have layers such as an electron transport layer, etc. The buffer layer may be the organic layer, and the electron transport layer may be a layer containing LiF, TiOx, ZnOx, etc.

[0078] The present invention includes the following embodiments. The present invention is not limited to the following embodiments. (1) An organic electronic material containing a branched charge-transporting polymer including a divalent structural unit having a substituted fluorene structure, at least one structural unit selected from the group consisting of a trivalent structural unit having a triphenylamine structure and a trivalent structural unit having a carbazole structure, and a monovalent structural unit having a polymerizable functional group. (2) The organic electronic material according to (1) above, wherein the substituted fluorene structure is a fluorene structure having a linear alkyl group having 4 to 18 carbon atoms. (3) The organic electronic material according to (1) or (2) above, wherein the charge-transporting polymer further includes a divalent structural unit having a triphenylamine structure having a fluoro group. (4) The organic electronic material according to any one of (1) to (3) above, wherein the charge-transporting polymer further includes a monovalent structural unit having a linear alkyl group having 4 to 18 carbon atoms. (5) The organic electronic material according to any one of (1) to (4) above, wherein the charge-transporting polymer is a material for a hole-injection layer. (6) The organic electronic material according to any one of (1) to (5) above, wherein the charge transporting polymer contains, based on all structural units, 30 to 60 mol % of divalent structural units having a fluorene structure having the substituent, 5 to 30 mol % of at least one structural unit selected from the group consisting of trivalent structural units having a triphenylamine structure and trivalent structural units having a carbazole structure, and 20 to 50 mol % of the monovalent structural unit having a polymerizable functional group. (7) The organic electronic material according to any one of (1) to (4) above, which is a material for a hole transport layer.(8) The organic electronic material according to any one of (1) to (4) and (7) above, wherein the charge-transporting polymer contains, based on all structural units, 5 to 35 mol % of divalent structural units having a fluorene structure having the substituent, 10 to 40 mol % of divalent structural units having a triphenylamine structure having a fluoro group, 5 to 30 mol % of at least one structural unit selected from the group consisting of trivalent structural units having a triphenylamine structure and trivalent structural units having a carbazole structure, 1 to 30 mol % of monovalent structural units having the polymerizable functional group, and 10 to 40 mol % of monovalent structural units having a linear alkyl group having 4 to 18 carbon atoms. (9) An organic electronic element comprising an organic layer formed using the organic electronic material according to any one of (1) to (8) above. (10) An organic electroluminescence element comprising at least one layer selected from the group consisting of a hole injection layer formed using the organic electronic material described in (5) or (6) above, and a hole transport layer formed using the organic electronic material described in (7) or (8) above. (11) An organic photoelectric conversion element comprising an organic layer formed using the organic electronic material described in any one of (1) to (8) above.

[0079] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-216094, filed December 21, 2023, the entire disclosure of which is incorporated herein by reference.

[0080] The embodiments of the present invention will be described below with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0081] <Synthesis of Charge Transporting Polymers 1 to 7> The charge transporting polymers were synthesized by Suzuki-Miyaura coupling using the monomers listed below. The monomers were blended in the ratios (mol percent) shown in Table 1.

[0082]

[0083]

[0084] (Preparation of Pd Catalyst) In a glove box under a nitrogen atmosphere, at room temperature, a fluororesin-coated magnetic stir bar was placed in a glass sample vial, and 73.2 mg (80 μmol) of tris(dibenzylideneacetone)dipalladium was weighed out. 15 mL of toluene was added and stirred for 30 minutes to obtain a solution. Similarly, a fluororesin-coated magnetic stir bar was placed in a glass sample vial, and 129.6 mg (640 μmol) of tris(t-butyl)phosphine was weighed out. 5 mL of toluene was added and stirred for 5 minutes to obtain a solution. These solutions were mixed and stirred at 80°C for 2 hours, and insoluble matter was removed using a 0.2 μm pore membrane filter. The resulting solution was used as a Pd catalyst solution. All solvents were degassed by bubbling nitrogen for at least 30 minutes before use.

[0085] (Synthesis of Charge-Transporting Polymer 1) Each monomer was weighed into a 100 mL three-necked round-bottom glass flask at the ratio shown in Table 1, with a total monomer amount of 10 mmol. 1.2 mL of a 1% by weight toluene solution of trioctylmethylammonium chloride, 2.2 mL of a 3 M aqueous potassium hydroxide solution, and toluene were added to a monomer concentration of 10% by weight. Next, a reflux condenser and a nitrogen gas flow tube were attached to the flask, and the flask was immersed in an oil bath heated to 120°C. The mixture was stirred under reflux for 10 minutes to dissolve the monomer. Subsequently, 0.3 mL of the Pd catalyst solution was added to the solution in the flask, and the mixture was heated to reflux for 2 hours. All reactions were carried out under a nitrogen stream. All solvents were degassed by bubbling nitrogen for at least 30 minutes before use.

[0086] After the reaction was completed, the flask was removed from the oil bath, and 5 mL of a 0.1 mol / L aqueous solution of sodium N,N-diethyldithiocarbamate was added and stirred for 5 minutes. The reaction solution was left to stand for 10 minutes, and the separated aqueous layer was removed, and the organic layer was washed with water. The organic layer was filtered through a membrane filter with a pore size of 0.2 μm, and the filtrate was poured into a methanol-water (9:1) mixed solution. The resulting precipitate was filtered off and washed with methanol. The precipitate was further washed with ethyl acetate, and the remaining solid was suction filtered and washed with methanol. After washing, the solid was vacuum dried, and charge-transporting polymer 1 was obtained.

[0087] (Synthesis of Charge Transporting Polymers 2 and 3) Each monomer was weighed out so as to have the compounding ratio shown in Table 1, and the same synthesis as for Charge Transporting Polymer 1 was carried out to obtain Charge Transporting Polymers 2 and 3.

[0088] (Synthesis of Charge Transporting Polymers 4 to 7) Each monomer was weighed out to have the compounding ratio shown in Table 1, and charge transporting polymers 4 to 7 were obtained in the same manner as in the synthesis of charge transporting polymer 1, except that anisole was used instead of toluene.

[0089] (Measurement of Number Average Molecular Weight, Measurement of Weight Average Molecular Weight) The number average molecular weight and weight average molecular weight of the charge transporting polymer were measured using gel permeation chromatography (hereinafter, referred to as GPC) under the following conditions. Apparatus: High-performance liquid chromatograph, Prominence, Shimadzu Corporation; Solution pump (LC-20AD); Degassing unit (DGU-20A); Autosampler (SIL-20AHT); Column oven (CTO-20A); PDA detector (SPD-M20A); Differential refractive index detector (RID-20A); Column: Gelpack GL-A160S (Serial number: 686-1J27); GL-A150S (Serial number: 685-1J27); Eluent: Tetrahydrofuran (THF) (for HPLC, contains stabilizer), Fujifilm Wako Pure Chemical Industries, Ltd.; Flow rate: 1 mL / min; Column temperature: 40°C; Detection wavelength: 254 nm; Molecular weight standard: PStQuick B / C / D, Tosoh Corporation.

[0090] Table 2 shows the number average molecular weight and weight average molecular weight of the charge transporting polymer.

[0091] <Evaluation of Organic Electronic Materials> (Evaluation of Solvent Resistance) 10.0 mg of a charge transporting polymer was weighed into a glass sample tube and dissolved in 0.9 mL of toluene, chlorobenzene, or cyclopentanone to prepare a charge transporting polymer solution. The charge transporting polymer solution was rotated on a quartz plate in the atmosphere at a rotation speed of 3,000 min. －１The quartz plate with the charge-transporting polymer layer formed thereon was then placed in a glove box under a nitrogen atmosphere and heated on a hot plate at 230°C for 30 minutes under a nitrogen atmosphere to carry out a curing reaction, forming an organic layer. The quartz plate with the organic layer formed thereon was immersed in 10 mL of toluene under atmospheric pressure and at room temperature and allowed to stand for 10 minutes. The remaining film percentage (%) of the organic layer was measured from the ratio of the absorbance (Abs) at the absorption maximum (λmax) in the visible-ultraviolet spectroscopy (UV-vis) spectrum before and after immersion in toluene. An organic layer with a high remaining film percentage (%) can be said to have excellent solvent resistance.

[0092]

[0093] (Evaluation of Solubility in Solvent) 10.0 mg of the charge transporting polymer was weighed into a glass sample tube, and 0.9 mL of toluene, anisole, chlorobenzene, cyclopentanone, cyclopentyl methyl ether, or butyl benzoate was added. The glass sample tube was capped and rotated at a speed of 100 min using a mix rotor. －１ The sample was visually inspected, and a transparent solution was evaluated as "Good", a dispersion or a cloudy liquid in which no precipitate formed at the bottom of the glass sample tube when the rotation was stopped and the sample was left to stand for 10 minutes was evaluated as "Good", and a dispersion or a cloudy liquid in which precipitate formed at the bottom of the glass sample tube when the rotation was stopped and the sample was left to stand for 10 minutes was evaluated as "Poor".

[0094]

Claims

1. An organic electronics material comprising a branched charge transporting polymer including a divalent structural unit having a substituted fluorene structure, at least one structural unit selected from the group consisting of a trivalent structural unit having a triphenylamine structure and a trivalent structural unit having a carbazole structure, and a monovalent structural unit having a polymerizable functional group.

2. The organic electronic material according to claim 1, wherein the fluorene structure having a substituent is a fluorene structure having a linear alkyl group having 4 to 18 carbon atoms.

3. The organic electronic material according to claim 1, wherein the charge transporting polymer further comprises a divalent structural unit having a triphenylamine structure having a fluoro group.

4. The organic electronic material according to claim 3, wherein the charge transporting polymer further comprises a monovalent structural unit having a linear alkyl group having 4 to 18 carbon atoms.

5. The organic electronic material according to claim 1, which is a material for a hole injection layer.

6. The organic electronic material according to claim 5, wherein the charge transporting polymer comprises, based on all structural units, 30 to 60 mol % of divalent structural units having a fluorene structure having the substituent, 5 to 30 mol % of at least one structural unit selected from the group consisting of trivalent structural units having a triphenylamine structure and trivalent structural units having a carbazole structure, and 20 to 50 mol % of monovalent structural units having a polymerizable functional group.

7. The organic electronic material according to claim 4, which is a material for a hole transport layer.

8. The organic electronic material according to claim 7, wherein the charge transporting polymer comprises, based on all structural units, 5 to 35 mol % of divalent structural units having a fluorene structure having the substituent, 10 to 40 mol % of divalent structural units having a triphenylamine structure having a fluoro group, 5 to 30 mol % of at least one structural unit selected from the group consisting of trivalent structural units having a triphenylamine structure and trivalent structural units having a carbazole structure, 1 to 30 mol % of monovalent structural units having the polymerizable functional group, and 10 to 40 mol % of monovalent structural units having a linear alkyl group having 4 to 18 carbon atoms.

9. An organic electronic device comprising an organic layer formed using the organic electronic material according to any one of claims 1 to 8.

10. An organic electroluminescence element comprising at least one layer selected from the group consisting of a hole injection layer formed using the organic electronic material described in claim 5, and a hole transport layer formed using the organic electronic material described in claim 7.

11. An organic photoelectric conversion element comprising an organic layer formed using the organic electronic material according to any one of claims 1 to 8.

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