TW202026327A - Organic electronic material, liquid composition, organic layer, organic electronic element, organic electroluminescent element, display element, lighting device, display device, and method for manufacturing organic electronic element - Google Patents

Abstract

One embodiment of the present invention relates to an organic electronic material which contains a charge transport polymer, and which is configured such that: the charge transport polymer has a branched structure; the charge transport polymer has a weight average molecular weight of 20,000 or more; and if a solution that contains the charge transport polymer and toluene and has a concentration of the charge transport polymer of 10% by mass is prepared, the viscosity of the solution at room temperature is less than 3.0 mPa·s.

Description

Organic electronic materials and organic electronic components

Embodiments of the present invention relate to an organic electronic material, a liquid composition, an organic layer, an organic electronic element, an organic electroluminescence element, a display element, a lighting device, a display device, and a method for manufacturing the organic electronic element.

Organic electronic devices use organic materials to perform electrical operations. They are expected to offer advantages such as energy efficiency, low cost, and flexibility, and are attracting attention as a technology that could replace existing inorganic semiconductors, which are primarily based on silicon. Examples of organic electronic devices include organic electroluminescent devices (organic EL devices), organic photoelectric converters, and organic transistors.

Organic EL devices are attracting attention as large-area solid-state light sources, serving as alternatives to incandescent lamps and gas-filled lamps. They are also gaining attention as the most promising self-luminous display to replace liquid crystal displays (LCDs) in the flat panel display (FPD) field, and their commercialization is progressing.

Organic EL devices are broadly classified into two types based on the organic materials used: low-molecular-weight organic EL devices and high-molecular-weight organic EL devices. High-molecular-weight organic EL devices use high-molecular-weight compounds as their organic materials, while low-molecular-weight organic EL devices use low-molecular-weight compounds. Organic EL device manufacturing methods are broadly divided into two types: dry processes, which primarily form films in a vacuum system, and wet processes, which form films using plate-based printing methods such as letterpress and gravure, or plateless printing methods such as inkjet. Due to its ability to easily form films, wet processes are expected to become essential for future large-screen organic EL displays.

Therefore, research is underway to develop materials suitable for wet processes. For example, research is underway to form multilayer structures using charge-transporting compounds with polymerizable functional groups (see Patent Document 1). [Prior Art Document] [Patent Document]

Patent document 1: Japanese Patent Publication No. 2006-279007

[Problem to be Solved by the Invention] In wet processes, a solution consisting of an organic material dissolved in a solvent is typically applied to form a coating layer, which is then dried to form the organic layer. Therefore, to form an organic layer with sufficient film thickness, a highly concentrated solution is preferred. However, solutions containing polymer compounds tend to increase in viscosity as their concentration increases. High solution viscosity can make it difficult to form an organic layer, depending on the coating method.

Therefore, an embodiment of the present invention aims to provide an organic electronic material and liquid composition capable of forming an organic layer having a sufficient film thickness by a wet process. Furthermore, an embodiment of the present invention aims to provide an organic layer having a sufficient film thickness that can be easily formed by a wet process. Furthermore, an embodiment of the present invention aims to provide an organic electronic device, an organic EL device, a display device, a lighting device, and a display device having excellent characteristics. [Means for Solving the Problem]

The present invention includes various embodiments. The following are examples of embodiments. The present invention is not limited to the following embodiments.

One embodiment relates to an organic electronic material comprising a charge transporting polymer having a branched structure and a weight-average molecular weight of 20,000 or greater. When a solution containing the charge transporting polymer and toluene at a concentration of 10% by mass of the charge transporting polymer is prepared, the viscosity of the solution at room temperature is less than 3.0 mPa·s.

Another embodiment relates to a liquid composition containing the organic electronic material and a solvent.

Yet another embodiment relates to an organic layer formed using the organic electronic material or the liquid composition.

Yet another embodiment relates to an organic electronic device including the organic layer.

Yet another embodiment relates to an organic electroluminescent device including the organic layer.

Yet another embodiment relates to a display element including the organic electroluminescent element; a lighting device including the organic electroluminescent element; or a display device including the lighting device and a liquid crystal element as a display component.

Yet another embodiment relates to a method for manufacturing an organic electronic device, comprising: forming an organic layer using the organic electronic material or the liquid composition. [Effects of the Invention]

According to embodiments of the present invention, an organic electronic material and liquid composition can be provided that enable formation of an organic layer having a sufficient film thickness by a wet process. Furthermore, according to embodiments of the present invention, an organic layer having a sufficient film thickness that can be easily formed by a wet process can be provided. Furthermore, according to embodiments of the present invention, an organic electronic device, an organic EL device, a display device, a lighting device, and a display device having excellent characteristics can be provided.

The present invention is not limited to the following embodiments.

<Organic Electronic Material> An embodiment of the present invention comprises an organic electronic material comprising a charge transporting polymer having a branched structure, a weight-average molecular weight of 20,000 or greater, and satisfying the following requirements: When a solution containing the charge transporting polymer and toluene at a concentration of 10% by mass of the charge transporting polymer is prepared, the viscosity of the solution at room temperature is less than 3.0 mPa·s.

Charge Transporting Polymers Charge transporting polymers are branched polymers with a branched structure within the molecule. The structural units that comprise the charge transporting polymers include at least trivalent or higher-valent structural units B and monovalent structural units T, and may also include divalent structural units. Structural units B form the branches. Structural units T form the terminal ends of the molecular chain. Structural units L preferably have charge transport properties.

The charge transporting polymer may contain only one or more of each structural unit. In the charge transporting polymer, each structural unit is bonded to each other at one to three or more bonding sites. Each structural unit is described below.

The weight-average molecular weight of the charge transporting polymer is 20,000 or greater. A weight-average molecular weight of 20,000 or greater allows the formation of an organic layer with excellent film-forming properties, heat resistance, and stability. The weight-average molecular weight is preferably 25,000 or greater, more preferably 30,000 or greater, and even more preferably 35,000 or greater. On the other hand, the weight-average molecular weight of the charge transporting polymer is preferably 1,000,000 or less, more preferably 700,000 or less, and even more preferably 400,000 or less. A weight-average molecular weight of 1,000,000 or less maintains good solubility in the solvent, allowing for easy preparation of a liquid composition. In particular, the weight-average molecular weight of the charge transporting polymer is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 80,000 or less. A weight-average molecular weight of 200,000 or less tends to facilitate the formation of thick organic layers. The viscosity of the solution tends to increase as the weight-average molecular weight of the charge transporting polymer increases, while the viscosity of the solution tends to decrease as the weight-average molecular weight of the charge transporting polymer decreases.

The number average molecular weight of the charge transporting polymer is preferably 10,000 or greater, more preferably 12,000 or greater, and even more preferably 15,000 or greater. When the number average molecular weight is 10,000 or greater, an organic layer with excellent film-forming properties, heat resistance, and stability can be formed. On the other hand, the number average molecular weight of the charge transporting polymer is preferably 500,000 or less, more preferably 100,000 or less. When the number average molecular weight is 500,000 or less, good solubility in the solvent is maintained, making it easy to prepare a liquid composition. In particular, the number average molecular weight of the charge transporting polymer is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. When the molecular weight is 50,000 or less, it tends to be easy to form a thick organic layer. The viscosity of the solution tends to increase as the number average molecular weight of the charge transporting polymer increases, and the viscosity of the solution tends to decrease as the number average molecular weight of the charge transporting polymer decreases.

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

GPC measurement conditions can be set to the following, for example. Equipment: High-Performance Liquid Chromatography (HPLC) Prominence, Shimadzu Corporation Liquid Delivery Pump (LC-20AD) Degassing Unit (DGU-20A) Autosampler (SIL-20AHT) Column Oven (CTO-20A) Photodiode Array (PDA) Detector (SPD-M20A) Differential Refractive Index Detector (RID-20A) Column: Gelpack (Registered Trademark) GL-A160S (Manufacturer Number: 686-1J27) GL-A150S (Manufacturer Number: 685-1J27) Hitachi Chemical Co., Ltd. Eluent: Tetrahydrofuran (THF) (High Performance Liquid Chromatography) Liquid Chromatography (HPLC), with stabilizer. Fujifilm Wako Pure Chemical Industries, Ltd. Flow rate: 1 mL/min Column temperature: 40°C Detection wavelength: 254 nm Molecular weight standards: PStQuick A/B/C Tosoh Corporation

The charge transport polymer is a polymer that satisfies the following requirements. When a solution containing the charge transport polymer and toluene is prepared at a concentration of 10% by mass of the charge transport polymer, the viscosity of the solution at room temperature is less than 3.0 mPa·s.

The viscosity is measured at room temperature (25°C). A solution adjusted to 25°C is used for the viscosity measurement. The concentration of the charge transport polymer is based on the mass of the solution. For example, a measuring device using VROC technology (Viscometer/Rheometer-on-a-Chip (VROC(R)) technology) can be used for the viscosity measurement. An example of a measuring device is "microVISCO (registered trademark)" manufactured by RheoSense. Multiple measurements can also be performed, and the average value of the multiple measurement values can be used as the viscosity value. Specifically, the measurement solution can be prepared by the method described in the embodiment. In addition, specifically, the viscosity of the solution can be measured by the method described in the embodiment.

When the viscosity of the solution is less than 3.0 mPa·s, an organic layer having a sufficient film thickness can be easily formed using a charge transport polymer. The viscosity of the solution is preferably less than 3.0 mPa·s, more preferably 2.8 mPa·s or less, and even more preferably 2.7 mPa·s or less. On the other hand, the lower limit of the viscosity is not particularly limited. The lower the viscosity, the easier it is to form an organic layer having a sufficient film thickness. For example, considering the workability when forming the organic layer, the viscosity of the solution is preferably 1.0 mPa·s or more, more preferably 1.5 mPa·s or more, and even more preferably 2.0 mPa·s or more.

The viscosity of the solution can be adjusted by changing the ratio of structural units in the charge transport polymer, the molecular weight of the charge transport polymer, etc.

Using a charge-transporting polymer with a 10% by mass toluene solution viscosity of less than 3.0 mPa·s yields a highly concentrated, low-viscosity liquid composition. By applying this highly concentrated, low-viscosity liquid composition to, for example, an inkjet method, it is possible to easily form an organic layer with a sufficient film thickness.

The charge-transporting polymer is preferably a hole-transporting polymer capable of transporting holes. More preferably, the charge-transporting polymer contains a structural unit comprising at least one structure selected from the group consisting of an aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a pyrrole structure, an aniline structure, and a phenoxazine structure. These structures may be substituted or unsubstituted. In addition, these structural units may be included as any structural unit having a valency of "monovalent" to "trivalent or higher." In other words, it is preferred that at least one of structural unit B, structural unit L, and structural unit T contains a structural unit comprising at least one structure selected from the group consisting of a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a pyrrole structure, an aniline structure, and a phenoxazine structure. More preferably, at least one of structural unit B, structural unit L, and structural unit T contains a structural unit comprising at least one structure selected from the group consisting of a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, and a pyrrole structure. More preferably, at least one of structural unit B, structural unit L, and structural unit T contains a structural unit comprising at least one structure selected from the group consisting of a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, and a pyrrole structure. The aromatic amine structure is preferably a structure selected from the group consisting of a diarylamine structure and a triarylamine structure, more preferably a triarylamine structure, and even more preferably a triphenylamine structure.

(Structure) The charge-transporting polymer is a branched polymer. This branched structure allows for efficient formation of an organic layer with sufficient film thickness.

According to a preferred embodiment, the branch structure includes at least one structural unit B and three or more structural units L bonded to the one structural unit B. Preferably, the branch structure includes a multi-branch structure, which has one structural unit B and three or more structural units L bonded to the one structural unit B, and each of the three or more structural units L has at least another structural unit B bonded to the structural unit L and two or more other structural units L bonded to the other structural unit B.

The following are examples of partial structures contained in charge-transporting polymers. Charge-transporting polymers are not limited to those 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 this specification, "*" indicates a bonding site with another structure. In the following partial structures, multiple Ls may be the same structural unit or different structural units. The same applies to T and B.

[Chemistry 1]

(Structural Unit L) Structural Unit L is preferably a divalent structural unit with charge transport properties. Structural Unit L is not particularly limited as long as it contains an atomic group capable of charge transport. For example, the structural unit L is selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a biphenyl structure, a triphenyl structure, a naphthalene structure, an anthracene structure, a fused tetraphenyl structure, a phenanthrene structure, a dihydrophenanthrene structure, a pyridine structure, a pyrazine structure, a quinoline structure, an isoquinoline structure, a quinoxaline structure, an acridine structure, a diazophene structure, a furan structure, a pyrrole structure, an oxazole structure, an oxadiazole structure, a thiazole structure, a thiadiazole structure, a triazole structure, a benzothiophene structure, a benzoxazole structure, a benzoxadiazole structure, a benzothiazole structure, a benzothiadiazole structure, a benzotriazole structure, and structures comprising one or more of these. The aromatic amine structure is preferably a structure selected from the group consisting of a diarylamine structure and a triarylamine structure, more preferably a triarylamine structure, and even more preferably a triphenylamine structure.

In one embodiment, from the perspective 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, an aniline structure, a phenoxazine structure, and structures comprising one or more thereof; more 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 structures comprising one or more thereof; further preferably selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a thiophene structure, a pyrrole structure, and structures comprising one or more thereof; and particularly preferably selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, and structures comprising one or more thereof. In another embodiment, from the perspective 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 structures containing one or more of these.

The following are specific examples of the structural unit L. The structural unit L is not limited to the following.

[Chemistry 2]

[Chemistry 3]

R each independently represents a hydrogen atom or a substituent. When R is a substituent, the substituent is preferably independently 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 polymerizable functional group described below. R ¹ represents a linear, cyclic, or branched alkyl group having 1 to 22 carbon atoms; or an aryl or heteroaryl group having 2 to 30 carbon atoms. ^{R 2} to R ⁸ each independently represent a hydrogen atom; a linear, cyclic, or branched alkyl group having 1 to 22 carbon atoms; or an aryl or heteroaryl group having 2 to 30 carbon atoms. The alkyl, aryl, and heteroaryl groups may be substituted or unsubstituted. Examples of substituents when alkyl, aryl, and heteroaryl groups further have substituents include -R ¹ , -OR ² , -SR ³ , -OCOR ⁴ , -COOR ⁵ , -SiR ⁶ R ⁷ R ⁸ , halogen atoms, and groups containing polymerizable functional groups described below, with -R ¹ being preferred. R is preferably a hydrogen atom, an alkyl group, an aryl group, an alkyl-substituted aryl group, a halogen atom, or a halogen-substituted alkyl group. Ar each independently represents a divalent linking group, such as an arylene group or a heteroarylene group. Ar is preferably an arylene group or a heteroarylene group having 2 to 30 carbon atoms, more preferably an arylene group having 2 to 30 carbon atoms, and even more preferably a phenylene group.

An aryl group is an atomic radical derived by removing one hydrogen atom from an aromatic hydrocarbon. A heteroaryl group is an atomic radical derived by removing one hydrogen atom from an aromatic heterocyclic compound. An arylene group is an atomic radical derived by removing two hydrogen atoms from an aromatic hydrocarbon. A heteroarylene group is an atomic radical derived by removing two hydrogen atoms from an aromatic heterocyclic compound.

Examples of aromatic hydrocarbons include monocyclic, fused, or polycyclic rings in which two or more selected from monocyclic and fused rings are directly bonded. Examples of aromatic heterocyclic compounds include monocyclic, fused, or polycyclic rings in which two or more selected from monocyclic and fused rings are directly bonded.

(Structural Unit B) When the charge transport polymer has a branched structure, structural unit B is a trivalent or higher valent structural unit that constitutes the branched portion. To improve the durability of the organic electronic device, structural unit B is preferably hexavalent or lower, more preferably pentavalent or lower, and even more preferably tetravalent or trivalent. Structural unit B is preferably a unit having charge transport properties. For example, to improve the durability of the organic electronic device, structural unit B is selected from a substituted or unsubstituted aromatic amine structure, a carbazole structure, a condensed polycyclic aromatic hydrocarbon structure, and structures containing one or more of these. The aromatic amine structure is preferably selected from the group consisting of a diarylamine structure and a triarylamine structure, more preferably a triarylamine structure, and even more preferably a triphenylamine structure.

The following are specific examples of the structural unit B. The structural unit B is not limited to the following.

[Chemistry 4]

W represents a trivalent linking group, for example, an aromatic triyl group or a heteroaromatic triyl group having 2 to 30 carbon atoms. Ar each independently represents a divalent linking group, for example, an arylene group or a heteroarylene group. Ar is preferably an arylene group or a heteroarylene group having 2 to 30 carbon atoms, more preferably an arylene group having 2 to 30 carbon atoms, and even more preferably a phenylene group. Y represents a direct bond or a divalent linking group, for example, a divalent group obtained by removing one hydrogen atom from R (excluding groups containing polymerizable functional groups) in the structural unit L. Z represents a carbon atom, a silicon atom, or a phosphorus atom. In the structural unit, the benzene ring and Ar may have a substituent. Examples of the substituent include R in the structural unit L.

An arene triyl group is an atomic group derived by removing three hydrogen atoms from an aromatic hydrocarbon. A heteroarene triyl group is an atomic group derived by removing three hydrogen atoms from an aromatic heterocyclic compound. Aromatic hydrocarbons and aromatic heterocyclic compounds are as described above.

(Structural Unit T) Structural unit T is a monovalent structural unit that constitutes the terminal portion of the charge transporting polymer. Structural unit T is not particularly limited and may be, for example, selected from a substituted or unsubstituted aromatic hydrocarbon structure, an aromatic heterocyclic structure, or a structure containing one or more of these. Structural unit T may have the same structure as structural unit L. In one embodiment, from the perspective of imparting durability without reducing charge transport, structural unit T is preferably a substituted or unsubstituted aromatic hydrocarbon structure, more preferably a substituted or unsubstituted benzene structure. Furthermore, in another embodiment, as described below, when the charge transporting polymer has a polymerizable functional group at its terminal portion, structural unit T may be a polymerizable structure (e.g., a polymerizable functional group such as a pyrrolyl group).

The following are specific examples of the structural unit T. The structural unit T is not limited to the following.

[Chemistry 5]

R is independently the same as R in the structural unit L. When the charge transporting polymer has a polymerizable functional group at the end, the structural unit T is preferably a structural unit comprising at least one of the R in the formula being a group containing a polymerizable functional group. In order to improve the solubility of the charge transporting polymer in the solvent, it is preferred that the structural unit T is preferably a structural unit comprising at least one of the R in the formula being an alkyl group or a fluoroalkyl group. The alkyl group is preferably a linear alkyl group, more preferably a linear alkyl group having 20 or less carbon atoms, and further preferably a linear alkyl group having 6 to 12 carbon atoms. The fluoroalkyl group is preferably a perfluoroalkyl group, more preferably a perfluoromethyl group or a perfluoroethyl group, and further preferably a perfluoromethyl group.

(Polymerizable Functional Group) In one embodiment, the charge transport polymer preferably has at least one polymerizable functional group, from the perspective of curing through polymerization and changing its solubility in a solvent. A "polymerizable functional group" refers to a functional group capable of forming a bond with heat, light, or the like.

Examples of the polymerizable functional group include: substituted or unsubstituted groups having carbon-carbon multiple bonds (e.g., vinyl, styryl, allyl, butenyl, ethynyl, acryl, acryloxy, acrylamido, methacryl, methacryloyloxy, methacryloamido, vinyloxy, vinylamido, etc.), groups having a small ring member (e.g., cyclopropyl, benzocyclobutenyl, cyclobutyl, etc. cyclic alkyl groups; cyclooxy groups (oxiranyl groups), oxetane groups (oxetanyl groups), group)) having a cyclic ether structure; diketene group; cyclic sulfhydryl group; lactone group; lactamide group, etc.), heterocyclic groups (such as furan-yl, pyrrol-yl, thien-yl, thiole-yl), etc.

When these groups are substituted, the substituents are not particularly limited, and examples thereof include linear, cyclic, or branched alkyl groups. The alkyl group preferably has 1 to 22 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 4 carbon atoms.

The polymerizable functional group is preferably a substituted or unsubstituted group having a cyclic ether structure or a group having a carbon-carbon multiple bond, more preferably a substituted or unsubstituted vinyl group, a styryl group, an acryl group, a methacryl group, an epoxy group, or an oxacyclobutane group. From the viewpoint of reactivity and the properties of the organic electronic device, a substituted or unsubstituted vinyl group or an oxacyclobutane group is further preferred.

To increase the degree of freedom of the polymerizable functional groups and facilitate polymerization reactions, the backbone structure of the charge transport polymer and the polymerizable functional groups can be bonded via a linking group such as an alkylene chain (e.g., a linear alkylene chain with 1 to 8 carbon atoms). The alkylene chain also tends to improve the solubility of the charge transport polymer in a solvent. Furthermore, when forming an organic layer on an electrode, for example, to enhance affinity for hydrophilic electrodes such as indium tin oxide (ITO), the charge transport polymer can be bonded via a hydrophilic linking group such as an ethylene glycol chain or a diethylene glycol chain. Furthermore, from the perspective of facilitating the preparation of monomers used to introduce polymerizable functional groups, one or more linking groups selected from ether bonds, ester bonds, and the like may be present between the skeleton structure and the polymerizable functional group.

On the other hand, when no linking groups such as alkylene chains, ethylene glycol chains, and diethylene glycol chains are present, the heat resistance of the organic layer tends to be improved.

Examples of the "group containing a polymerizable functional group" mentioned above include the "polymerizable functional group" itself and a group formed by combining a polymerizable functional group with a linking group such as an alkylene chain or an ether bond. As the group containing a polymerizable functional group, for example, the groups exemplified in International Publication No. 2010/140553 can be suitably used.

The polymerizable functional group can be introduced into the terminal portion (i.e., structural unit T) of the charge transporting polymer, into a portion other than the terminal portion (i.e., structural unit B or structural unit L), or into both the terminal portion and the portion other than the terminal portion. From the perspective of curability, it is preferred to introduce the polymerizable functional group at least into the terminal portion. From the perspective of achieving both curability and charge transport properties, it is preferred to introduce the polymerizable functional group only into the terminal portion. Furthermore, the polymerizable functional group can be introduced into the main chain of the charge transporting polymer, into the side chains, or into both the main chain and the side chains.

From the perspective of contributing to changes in solubility through curing, it is preferable that the charge transporting polymer contain a large amount of polymerizable functional groups. On the other hand, from the perspective of not hindering charge transport, it is preferable that the charge transporting polymer contain a small amount. The content of the polymerizable functional groups can be appropriately set in consideration of these factors.

For example, from the perspective of sufficient solubility and ease of multilayer formation, the number of polymerizable functional groups per molecule of the charge transporting polymer is preferably two or more, more preferably three or more. Furthermore, from the perspective of ensuring charge transport properties, the number of polymerizable functional groups is preferably 1,000 or less, more preferably 500 or less, and even more preferably 300 or less.

The number of polymerizable functional groups per molecule of a charge transporting polymer can be calculated as an average value using the amount of polymerizable functional groups added to synthesize the charge transporting polymer (e.g., the amount of monomers containing polymerizable functional groups), the amount of monomers corresponding to each structural unit, and the weight-average molecular weight of the charge transporting polymer. Alternatively, the number of polymerizable functional groups can be calculated as an average value using the ratio of the integrated value of the signal derived from the polymerizable functional groups in the ^1H nuclear magnetic resonance (NMR) spectrum of the charge transporting polymer to the integrated value of the entire spectrum, and the weight-average molecular weight of the charge transporting polymer.

(Ratio of Structural Units) From the perspective of suppressing the viscosity of the liquid composition and improving the durability of the organic electronic device, the ratio of structural unit B contained in the charge transport polymer, based on all structural units, is preferably 1 mol% or greater, more preferably 5 mol% or greater, and even more preferably 10 mol% or greater. Furthermore, from the perspective of suppressing the viscosity of the liquid composition and obtaining an organic layer with a sufficient film thickness, the ratio of structural unit B is preferably 17 mol% or less, more preferably 16 mol% or less, and even more preferably 15 mol% or less.

When the charge transport polymer contains structural units L, from the perspective of achieving sufficient charge transport properties, the proportion of structural units L, based on all structural units, is preferably 10 mol% or greater, more preferably 20 mol% or greater, and even more preferably 30 mol% or greater. Furthermore, considering structural units T and B, the proportion of structural units L is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

From the perspective of improving the properties of organic electronic devices, suppressing viscosity increases, and successfully synthesizing a charge transporting polymer, the proportion of structural units T contained in the charge transporting polymer is preferably 5 mol% or greater, more preferably 10 mol% or greater, and even more preferably 15 mol% or greater, based on all structural units. Furthermore, from the perspective of achieving sufficient charge transport properties, the proportion of structural units T is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less.

For example, in a charge transporting polymer comprising structural units L, T, and B, the ratio of structural units L, T, and B preferably satisfies L:T:B = ((2x + 100)/3):(200 - 5x)/3):x. x is the molar ratio of structural unit B relative to all structural units in the charge transporting polymer. x is preferably 1 molar% or greater, more preferably 5 molar% or greater, and even more preferably 10 molar% or greater. x is preferably 17 molar% or less, more preferably 16 molar% or less, and even more preferably 15 molar% or less. It is generally believed that a greater proportion of structural unit B results in a lower solution viscosity. However, to achieve a viscosity of less than 3.0 mPa·s, x is preferably 17 molar% or less.

When the charge transport polymer has polymerizable functional groups, from the perspective of efficiently curing the charge transport polymer, the ratio of polymerizable functional groups, based on all structural units, is preferably 0.1 mol% or greater, more preferably 1 mol% or greater, and even more preferably 3 mol% or greater. Furthermore, from the perspective of achieving good charge transport properties, the ratio of polymerizable functional groups is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. The term "ratio of polymerizable functional groups" herein refers to the ratio of structural units having polymerizable functional groups.

Considering the balance between charge transportability, durability, and productivity, the ratio (molar ratio) of structural unit L, structural unit T, and structural unit B is preferably L:T:B = 100:10 to 200:10 to 100, more preferably 100:20 to 180:20 to 90, and even more preferably 100:40 to 160:30 to 80.

The ratio of the structural units can be determined using the amount of monomer corresponding to each structural unit used to synthesize the charge transporting polymer. Alternatively, the ratio of the structural units can be calculated by averaging the integral of the spectra derived from each structural unit in the ^1H NMR spectrum of the charge transporting polymer. For simplicity, when the amount of addition is known, it is preferable to use the value determined using the amount.

(Production Method) Charge transport polymers can be produced using a variety of synthetic methods, without particular limitation. For example, well-known coupling reactions such as the Suzuki coupling, Negishi coupling, Sonogashira coupling, Stille coupling, and Buchwald-Hartwig coupling can be utilized. The Suzuki coupling is a Pd-catalyzed cross-coupling reaction between an aromatic boronic acid derivative and an aromatic halide. Using the Suzuki coupling, charge transport polymers can be easily produced by bonding desired aromatic rings.

In the coupling reaction, catalysts such as Pd(0) compounds, Pd(II) compounds, and Ni compounds are used. Alternatively, catalysts produced by mixing tris(dibenzylideneacetone)dipalladium(0) or palladium(II) acetate with a phosphine ligand as a precursor may be used. For the synthesis of charge-transporting polymers, see, for example, International Publication No. 2010/140553.

[Dopant] Organic electronic materials may contain any additives, including, for example, dopants. Dopants are not particularly limited, as long as they exhibit a doping effect and enhance charge transport when added to the organic electronic material. Doping can be either p-type or n-type. For p-type doping, the dopant acts as an electron acceptor, while for n-type doping, the dopant acts as an electron donor. P-type doping is preferred for improving hole transport, while n-type doping is preferred for improving electron transport. Dopants used in organic electronic materials can exhibit either p-type or n-type doping effects. A single dopant may be added, or a mixture of multiple dopants may be added.

The dopant used in p-type doping is an electron-accepting compound, such as Lewis acids, protonic acids, transition metal compounds, ionic compounds, halogen compounds, and π-conjugated compounds. Specifically, examples of Lewis acids include FeCl ₃ , PF ₅ , AsF ₅ , SbF ₅ , BF ₅ , BCl ₃ , and BBr ₃ ; examples of protonic acids include inorganic acids such as HF, HCl, HBr, HNO ₃ , H ₂ SO ₄ , and HClO ₄ ; and organic acids such as benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, polyvinylsulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, 1-butanesulfonic acid, vinylphenylsulfonic acid, and camphorsulfonic acid ; and examples of transition metal compounds include FeOCl, TiCl ₄ , ZrCl ₄ , HfCl ₄ , NbF ₅ , AlCl ₃ , NbCl ₅ , TaCl ₅ , and MoF ₅ Examples of ionic compounds include tetrakis(pentafluorophenyl)borate ions, tris(trifluoromethanesulfonyl)methide ions, bis(trifluoromethanesulfonyl)imide ions, hexafluoroantimonate ions, AsF ₆ ^- (hexafluoroarsenate ions), BF ₄ ^- (tetrafluoroborate ions), PF ₆ ^- (hexafluorophosphate ions), and salts having a conjugate base of the above-mentioned protonic acid as an anion. Examples of halogen compounds include Cl ₂ , Br ₂ , I ₂ , ICl ₃ , IBr, IF, etc.; examples of π-conjugated compounds include TCNE (tetracyanoethylene) and TCNQ (tetracyanoquinodimethane). Other known electron-accepting compounds can also be used. Preferred are Lewis acids, ionic compounds, and π-conjugated compounds.

The dopant used in 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; salts of alkali metals and/or alkaline earth metals _such as LiF and _Cs2CO3 ; metal complexes; electron-donating organic compounds, etc.

When the charge transport polymer has a polymerizable functional group, it is preferable to use a compound that can function as a polymerization initiator for the polymerizable functional group as a dopant in order to easily change the solubility by hardening the organic layer.

[Other Optional Ingredients] Organic electronic materials may further contain charge-transporting low-molecular-weight compounds, other polymers, etc.

[Content] To achieve good charge transport properties, the charge transport polymer content in the organic electronic material is preferably 50% by mass or greater, more preferably 70% by mass or greater, and even more preferably 80% by mass or greater, relative to the total mass of the organic electronic material. The upper limit of the charge transport polymer content is not particularly limited and can be 100% by mass. Taking into account the inclusion of additives such as dopants, the charge transport polymer content can be set to, for example, 95% by mass or less, or 90% by mass or less.

When a dopant is included, from the perspective of improving the charge transport properties of the organic electronic material, the dopant content is preferably 0.01% by mass or greater, more preferably 0.1% by mass or greater, and even more preferably 0.5% by mass or greater, relative to the total mass of the organic electronic material. Furthermore, from the perspective of maintaining good film-forming properties, the dopant content is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, relative to the total mass of the organic electronic material.

<Liquid Composition> The liquid composition of an embodiment of the present invention contains the aforementioned organic electronic material and a solvent. This liquid composition containing a solvent allows for easy formation of an organic layer using simple methods such as coating. The liquid composition can be used as an ink composition.

[Solvent] The solvent may be any solvent, such as water, an organic solvent, or a mixture thereof. Examples of organic solvents include: alcohols such as methanol, ethanol, and isopropyl alcohol; alkanes such as pentane, hexane, and octane; cycloalkanes such as cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetrahydronaphthalene, 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, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4- Aromatic ethers such as methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole; 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; dimethyl sulfoxide, tetrahydrofuran, acetone, chloroform, and dichloromethane. Preferred solvents include aromatic hydrocarbons, aliphatic esters, aromatic esters, aliphatic ethers, and aromatic ethers, and more preferred solvents include aromatic hydrocarbons.

[Polymerization Initiator] If the charge transport polymer has a polymerizable functional group, the liquid composition preferably contains a polymerization initiator. Examples of polymerization initiators include known free radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators. To facilitate preparation of the liquid composition, it is preferable to use a substance that functions as both a dopant and a polymerization initiator. Examples of such substances include the aforementioned ionic compounds.

[Additives] The liquid composition may further contain additives as optional ingredients. Examples of additives include polymerization inhibitors, stabilizers, thickeners, gelling agents, flame retardants, antioxidants, reduction inhibitors, oxidizing agents, reducing agents, surface modifiers, emulsifiers, defoaming agents, dispersants, and surfactants.

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

<Organic Layer> The organic layer in embodiments of the present invention is formed using the aforementioned organic electronic material or liquid composition. The organic layer exhibits excellent charge transport properties. Using a liquid composition allows for efficient and simple coating. Examples of coating methods include spin coating, casting, dipping, plate printing methods such as relief printing, gravure printing, offset printing, lithography, letterpress reverse offset printing, screen printing, and gravure printing, and plateless printing methods such as inkjet printing. When the organic layer is formed by coating, the coating layer obtained after coating can be dried by heat treatment to remove the solvent.

If the charge transport polymer has polymerizable functional groups, polymerization can be initiated by light irradiation or heat treatment, altering the solubility of the coating layer. Heat treatment is preferred for simplicity. By stacking the organic layers obtained by altering the solubility of the coating layer, multilayered organic electronic devices can be easily achieved.

The heat treatment can be performed in an atmospheric environment or an inert gas environment. Examples of inert gases include helium, argon, nitrogen, and mixtures thereof. The "inert gas environment" preferably has an inert gas concentration of 99.5% or greater by volume, more preferably 99.9% or greater, and even more preferably 99.99% or greater.

The heat treatment can be performed using a heater such as a hot plate or an oven. To perform the heat treatment in an inert gas environment, for example, a hot plate can be used in an inert gas environment, or an oven can be set to an inert gas environment.

From the perspective of efficiently removing the solvent, the heat treatment is preferably performed at a temperature above the boiling point of the solvent. Furthermore, when the polymerization reaction of the charge transport polymer is being carried out, a temperature at which the polymerization reaction proceeds efficiently is preferred. In one embodiment, the heat treatment temperature is preferably 140°C or higher, more preferably 180°C or higher, and even more preferably 190°C or higher. On the other hand, from the perspective of suppressing degradation caused by the heat treatment, the temperature is preferably 300°C or lower, more preferably 280°C or lower, and even more preferably 250°C or lower.

From the perspective of improving charge transfer efficiency, the thickness of the organic layer after drying or curing is preferably 0.1 nm or greater, more preferably 1 nm or greater, and even more preferably 3 nm or greater. Furthermore, from the perspective of reducing electrical resistance, 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.

<Organic Electronic Component> An organic electronic component according to an embodiment of the present invention comprises at least one organic layer. Examples of such an organic electronic component include an organic EL element, an organic photoelectric conversion element, and an organic electronic crystal. The organic electronic component preferably has a structure in which the organic layer is disposed between at least one pair of electrodes. The organic electronic component can be manufactured by a manufacturing method comprising forming the organic layer using the organic electronic material or the liquid composition.

<Organic EL Device> An organic EL device according to an embodiment of the present invention comprises at least one organic layer as described above. An organic EL device typically includes a light-emitting layer, an anode, a cathode, and a substrate, and optionally includes other functional layers such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer. Each layer can be formed by evaporation or coating. The organic EL device preferably comprises the organic layer as a light-emitting layer or another functional layer, more preferably as another functional layer, and even more preferably as at least one of a hole injection layer and a hole transport layer.

Figure 1 is a schematic cross-sectional view of one embodiment of an organic EL element. The organic EL element in Figure 1 has a multi-layer structure, comprising, in order: 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.

[Luminescent Layer] The materials used in the luminescent layer include low molecular weight compounds, polymers, dendrimers, and other luminescent materials. Polymers are preferred due to their high solubility in solvents and suitability for coating. Examples of luminescent materials include fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF).

Examples of fluorescent materials include low molecular weight compounds such as pyrene, coumarin, rubrene, quinacridone, stilbene, dye laser pigments, aluminum complexes, and their derivatives; polymers such as polyfluorene, polyphenylene glycol, polyphenylene vinylene, polyvinylcarbazole, fluorene-benzothiadiazole copolymers, fluorene-triphenylamine copolymers, and their derivatives; and mixtures thereof.

As phosphorescent materials, metal complexes containing metals such as Ir and Pt can be used. Examples of Ir complexes include FIr(pic) (iridium(III)bis[(4,6-difluorophenyl)pyridine-N,C ² ]picolinate), which emits blue light; Ir(ppy) ₃ (fa-tris(2-phenylpyridinium)iridium), which emits green light; (btp) ₂ Ir(acac) (bis[2-(2'-benzo[4,5-α]thienyl)pyridinium-N,C ³ ]iridium (acetylacetonate), which emits red light; and Ir(piq) ₃ (tris(1-phenylisoquinolinium)iridium). Examples of Pt complexes include PtOEP (2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum), which emits red light.

When the light-emitting layer includes a phosphorescent material, it preferably includes a host material in addition to the phosphorescent material. The host material can be a low molecular weight compound, a polymer, or a dendrimer. Examples of low molecular weight compounds include CBP (4,4'-bis(9H-carbazol-9-yl)biphenyl), mCP (1,3-bis(9-carbazol-1-yl)benzene), CDBP (4,4'-bis(carbazol-9-yl)-2,2'-dimethylbiphenyl), and their derivatives. Examples of polymers include the aforementioned organic electronic materials, polyvinylcarbazole, polyphenylene glycol, polyfluorene, and their derivatives.

Examples of thermally activated delayed fluorescence materials include PIC-TRZ (2-biphenyl-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine), Spiro-C N (2',7'-bis(di-p-tolylamino)-9,9'-spirobifluorene-s,7-dicarbonitrile), CC2TA (2,4-bis{3-(9H-carbazol-9-yl)-9H-carbazol-9-yl}-6-phenyl-1,3,5 -triazine)(2,4-bis{3-(9H-carbazol-9-yl)-9H-carbazol-9-yl}-6-phenyl-1,3,5-triazine), CZ-PS (9,9'-(4,4'-sulfonylbis(4,1-phenylene))bis(3,6-di-tert-butyl-9H-carbazole)), 4CzPN (3,4,5,6-tetra(9H-carbazol-9-yl)phthalonitrile), HAP-3TPA (4,4',4''-(1,3,3a Compounds such as ^1,4,6,7,9 -heptaazaphenalene-2,5,8-triyl)tris(N,N-bis(4-(tert-butyl)phenyl)aniline)), 4CzIPN(1,2,3,5-tetrakis ⁽ carbazol-9-yl)-4,6-dicyanobenzene), and others.

[Hole Injection Layer, Hole Transport Layer] Preferably, the organic layer described above serves as at least one of a hole injection layer and a hole transport layer. As described above, these layers can be easily formed using a liquid composition comprising an organic electronic material and a solvent.

When the organic EL element includes the aforementioned organic layer as a hole injection layer and further includes a hole transport layer, a known material can be used for the hole transport layer. Furthermore, when the organic EL element includes the aforementioned organic layer as a hole transport layer and further includes a hole injection layer, a known material can be used for the hole injection layer. Alternatively, both the hole injection layer and the hole transport layer may be the aforementioned organic layer. Examples of known materials include aromatic amine compounds (e.g., aromatic diamines such as N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (α-NPD)), phthalocyanine compounds, and thiophene compounds (e.g., thiophene-based conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)).

If the hole transport layer is an organic layer whose solubility changes through polymerization, a light-emitting layer can be easily formed on top of it using a wet process. In this case, the polymerization initiator can be contained in the organic layer serving as the hole transport layer or in an organic layer located below the hole transport layer.

[Electron Transport Layer, Electron Injection Layer] Examples of materials used in the electron transport layer and electron injection layer include phenanthroline derivatives, bipyridine derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, fused-ring tetracarboxylic anhydrides such as naphthalene and perylene, carbodiimides, fluorenylidenemethane derivatives, anthraquinone dimethane and anthrone derivatives, oxadiazole derivatives, thiadiazole derivatives, benzimidazole derivatives, quinoxaline derivatives, and aluminum complexes. Additionally, the aforementioned organic electronic materials may be used.

[Cathode] Cathode materials include metals or metal alloys such as Li, Ca, Mg, Al, In, Cs, Ba, Mg/Ag, LiF, and CsF.

[Anode] Anode materials include metals (e.g., Au) or other conductive materials. Examples of other materials include oxides (e.g., ITO: indium oxide/tin oxide) and conductive polymers (e.g., polythiophene-polystyrene sulfonate mixture (PEDOT:PSS)).

[Substrate] The substrate can be made of glass, plastic, or other materials. It is preferably transparent and flexible. Quartz glass or resin film are suitable.

The resin film is preferably a light-transmitting resin film. Examples of the resin film include films containing polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyether imide, polyether ether ketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, cellulose triacetate, cellulose acetate propionate, and the like as main components.

When using a resin film, in order to suppress the permeation of water vapor, oxygen, etc., the resin film can also be coated with inorganic materials such as silicon oxide and silicon nitride.

[Sealing] To reduce the effects of external gases and extend their lifespan, organic EL elements can be sealed. Materials used for sealing include, but are not limited to, glass, epoxy resins, acrylic resins, plastic films such as polyethylene terephthalate, and polyethylene naphthalate, or inorganic materials such as silicon oxide and silicon nitride. The sealing method is also not particularly limited and can be performed using known methods.

[Luminescence Color] There are no specific restrictions on the color of light emitted by organic EL devices. White organic EL devices are preferred for use in various lighting fixtures, including home lighting, interior lighting, clocks, and LCD backlights.

One method for creating white organic EL elements is to use multiple luminescent materials to simultaneously emit multiple colors, thereby mixing colors. The combination of multiple luminescent colors is not particularly limited, but examples include combinations with three maximum emission wavelengths: blue, green, and red; combinations with two maximum emission wavelengths: blue and yellow, or yellow-green and orange. The luminescent color can be controlled by adjusting the type and amount of luminescent materials.

<Display Element, Illuminating Device, Display Device> A display element as an embodiment of the present invention includes the aforementioned organic EL element. For example, by using organic EL elements as elements corresponding to red, green, and blue (RGB) pixels, a color display can be achieved. Image formation methods include simple matrix type, in which individual organic EL elements arranged on a flat plate are directly driven by electrodes arranged in a matrix, and active matrix type, in which thin-film transistors are placed on each element for driving.

In addition, an illumination device according to an embodiment of the present invention includes the organic EL element. Furthermore, a display device according to an embodiment of the present invention includes an illumination device and a liquid crystal element as a display component. For example, the display device can be a liquid crystal display device that uses the illumination device as a backlight and a known liquid crystal element as a display component.

<Examples of Implementation> The following are some preferred examples of implementation of the present invention. The implementation of the present invention is not limited to the following examples.

(1) An organic electronic material comprising a charge transporting polymer, wherein the charge transporting polymer has a branched structure, the weight average molecular weight of the charge transporting polymer is 20,000 or greater, and when a solution containing the charge transporting polymer and toluene at a concentration of 10% by mass of the charge transporting polymer is prepared, the viscosity of the solution at room temperature is less than 3.0 mPa·s.

(2) The organic electronic material according to (1), wherein the charge transporting polymer contains trivalent or higher valent structural units, and the content of the trivalent or higher valent structural units is 17 mol% or less based on all structural units.

(3) The organic electronic material according to (2), wherein the charge transporting polymer further contains a divalent structural unit and a monovalent structural unit.

(4) The organic electronic material according to any one of (1) to (3), wherein the charge transporting polymer contains a structural unit comprising at least one structure selected from the group consisting of an aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a pyrrole structure, an aniline structure, and a phenoxazine structure.

(5) The organic electronic material according to any one of (1) to (4), wherein the charge transporting polymer has at least one polymerizable functional group.

(6) The organic electronic material according to any one of (1) to (5), wherein the charge transporting polymer is a hole transporting polymer.

(7) A liquid composition comprising: the organic electronic material according to any one of (1) to (6); and a solvent.

(8) An organic layer formed using the organic electronic material described in any one of (1) to (6) above, or the liquid composition described in (7) above.

(9) An organic electronic device comprising the organic layer described in (8).

(10) An organic electroluminescent element comprising the organic layer described in (8).

(11) An organic electroluminescent element comprising the organic layer described in (8) as a hole injection layer or a hole transport layer.

(12) A display element comprising the organic electroluminescent element as described in (10) or (11).

(13) A lighting device comprising the organic electroluminescent element as described in (10) or (11).

(14) A display device comprising: the lighting device as described in (13); and a liquid crystal element as a display component.

(15) A method for manufacturing an organic electronic element, comprising: forming an organic layer using the organic electronic material described in any one of (1) to (6) or the liquid composition described in (7).

The content disclosed in this application is related to the subject matter described in Japanese Patent Application No. 2018-183978, filed on September 28, 2018, and the entire disclosure of that application is incorporated herein by reference. [Examples]

The present invention will be described in more detail below using examples. The present invention is not limited to the following examples. <Preparation of Charge Transport Polymer> [Preparation of Pd Catalyst] In a glove box under a nitrogen atmosphere, tris(dibenzylideneacetone)dipalladium (73.2 mg, 80 μmol) was weighed into a sample tube at room temperature, toluene (15 mL) was added, and the mixture was stirred for 30 minutes. Similarly, tri(tert-butyl)phosphine (129.6 mg, 640 μmol) was weighed into a sample tube, toluene (5 mL) was added, and the mixture was stirred for 5 minutes. These solutions were mixed and stirred at room temperature for 30 minutes to obtain a catalyst solution (hereinafter referred to as the "Pd catalyst solution"). In the preparation of Pd catalysts, all solvents were degassed by nitrogen bubbling for more than 30 minutes before use.

[Preparation of Charge Transporting Polymers] Charge transporting polymers 1 to 8 were prepared using the following monomers.

[Chemistry 6]

(Charge Transporting Polymer 1) To a three-necked round-bottom flask, monomer A1 (3.0 mmol), monomer B1 (1.0 mmol), monomer C1 (3.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (15 mL) were added. The Pd catalyst solution (1.0 mL) was then added and mixed. The resulting mixture was heated under reflux for 2 hours. All operations to this point were performed under a nitrogen flow. All solvents were degassed by bubbling nitrogen for at least 30 minutes before use.

After the reaction is complete, the organic layer is washed with water and poured into a 9:1 methanol-water mixture. The resulting precipitate is recovered by suction filtration and washed with 9:1 methanol-water mixture. The resulting precipitate is dissolved in toluene and reprecipitated from methanol. The resulting precipitate is recovered by suction filtration and dissolved in toluene. A metal adsorbent (200 mg of "triphenylphosphine polymer-bound on styrene-divinylbenzene copolymer" manufactured by Strem Chemicals, per 100 mg of precipitate) is added and stirred at 80°C for 2 hours. After stirring, the metal adsorbent and insoluble matter were removed by filtration, followed by reprecipitation from methanol. The resulting precipitate was recovered by suction filtration and washed with methanol. The resulting precipitate was vacuum dried to obtain charge transport polymer 1. Charge transport polymer 1 had a number average molecular weight of 7,600 and a weight average molecular weight of 36,000.

The number average molecular weight and weight average molecular weight were measured by GPC (polystyrene equivalent) using tetrahydrofuran (THF) as the washing liquid. The measurement conditions were as described above.

(Charge Transporting Polymer 2) In a three-necked round-bottom flask, monomer A1 (3.0 mmol), monomer B1 (1.0 mmol), monomer C1 (1.5 mmol), monomer C2 (1.5 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (17 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for the preparation of charge transporting polymer 1 were then followed to obtain charge transporting polymer 2. Charge transporting polymer 2 had a number average molecular weight of 8,700 and a weight average molecular weight of 36,000.

(Charge Transporting Polymer 3) In a three-necked round-bottom flask, monomer A1 (3.0 mmol), monomer B1 (1.0 mmol), monomer C1 (1.5 mmol), monomer C3 (1.5 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (17 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 3. Charge transporting polymer 3 had a number average molecular weight of 12,200 and a weight average molecular weight of 40,000.

(Charge Transporting Polymer 4) To a three-necked round-bottom flask, monomer A1 (3.0 mmol), monomer B1 (1.0 mmol), monomer C4 (3.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (17 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 4. Charge transporting polymer 4 had a number average molecular weight of 10,000 and a weight average molecular weight of 36,000.

(Charge Transporting Polymer 5) To a three-necked round-bottom flask, monomer A1 (5.0 mmol), monomer B1 (2.0 mmol), monomer C1 (4.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (50 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 5. Charge transporting polymer 5 had a number average molecular weight of 8,720 and a weight average molecular weight of 30,000.

(Charge Transporting Polymer 6) To a three-necked round-bottom flask, monomer A1 (5.0 mmol), monomer B1 (2.0 mmol), monomer C1 (2.0 mmol), monomer C2 (2.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (50 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 6. Charge transporting polymer 6 had a number average molecular weight of 12,000 and a weight average molecular weight of 60,000.

(Charge Transporting Polymer 7) To a three-necked round-bottom flask, monomer A1 (5.0 mmol), monomer B1 (2.0 mmol), monomer C1 (2.0 mmol), monomer C3 (2.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (50 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 7. Charge transporting polymer 7 had a number average molecular weight of 15,000 and a weight average molecular weight of 56,000.

(Charge Transporting Polymer 8) In a three-necked round-bottom flask, monomer A1 (5.0 mmol), monomer B1 (2.0 mmol), monomer C4 (4.0 mmol), methyltri-n-octylammonium chloride (Alfa Aesar Aliquat 336) (0.03 g), potassium hydroxide (1.12 g), pure water (5.54 mL), and toluene (50 mL) were added. Pd catalyst solution (1.0 mL) was then added and mixed. The same procedures as for charge transporting polymer 1 were then followed to obtain charge transporting polymer 8. Charge transporting polymer 8 had a number average molecular weight of 13,000 and a weight average molecular weight of 40,000.

[Viscosity Measurement] Toluene solutions were prepared using charge transport polymers 1 to 8, and the viscosities of the toluene solutions were measured.

50 mg of each charge transport polymer was weighed into a sample tube, and 520 μL of toluene was added. The sample was then left at room temperature (25°C) for 5 hours to dissolve the charge transport polymer in the toluene, resulting in an evaluation solution. The viscosity of the evaluation solution was measured using a microVISCO (registered trademark) instrument manufactured by RheoSense. Five measurements were performed, and the average of the five measured values was calculated as the viscosity of the evaluation solution. The viscosities are shown in Table 1.

[Table 1] Table 1 polymer Viscosity (mPa·s) Charge transport polymer 1 2.4 Charge transport polymer 2 2.6 Charge transport polymer 3 2.7 Charge transport polymer 4 2.0 Charge transport polymer 5 3.3 Charge transport polymer 6 3.2 Charge transport polymer 7 3.1 Charge transport polymer 8 3.0

By using an organic electronic material containing a charge-transporting polymer with a viscosity of less than 3.0 mPa·s as a 10% by mass toluene solution, it is possible to produce an ink composition with high concentration and low viscosity. Using an ink composition with high concentration and low viscosity makes it easy to form thick organic layers.

<Evaluation of the solubility of charge transporting polymers (organic electronic materials)> The solubility of charge transporting polymers 1 to 8 in a solvent was evaluated. 10 mg of each charge transporting polymer was weighed into a sample tube (manufactured by ASONE Co., Ltd., 6 mL). Then, a stirring blade was placed, and 1,145 μL of toluene (25°C) was added at room temperature (25°C), and stirred using a stirrer (speed 600 min ^-1 ). Regarding the dissolution time, the time required for the polymer mixture to become transparent after the addition of toluene was visually observed (dissolution time) was measured. The solubility of the charge transporting polymer was evaluated according to the following criteria. The dissolution time and evaluation results are shown in Table 2. A: Dissolution time is less than 5 minutes B: Dissolution time exceeds 5 minutes

[Table 2] Table 2 polymer Dissolution time (minutes) Reviews Charge transport polymer 1 1.5 A Charge transport polymer 2 2.5 A Charge transport polymer 3 3.0 A Charge transport polymer 4 2.5 A Charge transport polymer 5 10.0 B Charge transport polymer 6 11.0 B Charge transport polymer 7 11.0 B Charge transport polymer 8 6.0 B

As shown in Table 2, charge transport polymers 1 to 4 had short dissolution times. This indicates that organic electronic materials containing a charge transport polymer that has a viscosity of less than 3.0 mPa·s as a 10% by mass toluene solution exhibit high solubility.

<Fabrication and Evaluation of Organic EL Devices> [Fabrication of Organic EL Devices] (Organic EL Device 1) Charge transport polymer 1 (10.0 mg) was dissolved in toluene (2,200 μL) to obtain a polymer solution. Separately, the following onium salt (0.1 mg) was dissolved in toluene (100 μL) to obtain an onium salt solution. The resulting polymer solution and onium salt solution were mixed to prepare an ink composition containing charge transport polymer 1. The ink composition was spin-coated at 3,000 ^min⁻¹ on a 1.6 mm wide glass substrate patterned with ITO under atmospheric pressure. The substrate was then heated at 200°C on a hot plate for 30 minutes to form a hole injection layer (20 nm).

[Chemistry 7]

The glass substrate was then moved to a vacuum evaporator, where NPD (40 nm), CBP:Ir(ppy) ₃ (94:6, 30 nm), BAlq (10 nm), Alq ₃ (30 nm), LiF (0.8 nm), and Al (100 nm) were deposited on the hole injection layer in that order. This was then sealed to create an organic EL device.

(Organic EL Elements 2-8) Organic EL Elements 2-8 were fabricated in the same manner as Organic EL Element 1, except that Charge Transporting Polymers 2-8 were used instead of Charge Transporting Polymer 1.

[Evaluation of Organic EL Devices] Green luminescence was confirmed when voltage was applied to the organic EL devices obtained above. For each device, the driving voltage and luminous efficiency at a luminance of 1,000 cd/ ^m² , as well as the luminous life (half-luminance reduction time) at an initial luminance of 5,000 cd/ ^m² , were measured. The results are shown in Table 3.

[Table 3] Table 3 Driving voltage (V) Luminous efficiency (cd/A) Luminous lifespan (hours) Organic EL element 1 7.0 30.0 313 Organic EL element 2 7.0 29.0 312 Organic EL element 3 7.1 29.6 309 Organic EL elements 4 7.2 28.0 310 Organic EL device 5 7.0 31.0 311 Organic EL element 6 7.0 30.4 308 Organic EL device 7 7.1 29.0 315 Organic EL elements 8 7.2 28.5 309

As shown in Table 3, the organic EL devices fabricated using charge transport polymers 1 to 8 exhibited comparable driving voltages, luminescence efficiencies, and luminescence lifetimes.

As described above, by using an organic electronic material containing a charge transporting polymer having a viscosity of less than 3.0 mPa·s as a 10 mass % toluene solution, an organic layer having a sufficient film thickness can be formed without affecting the characteristics of the organic electronic device.

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

FIG1 is a schematic cross-sectional view showing an example of an organic EL element as an embodiment of the present invention.

1: Luminescent layer

2: Anode

3: Hole injection layer

4: Cathode

5: Electron injection layer

6: Hole transport layer

7: Electron transmission layer

8:Substrate

Claims (15)

An organic electronic material comprising a charge transporting polymer, the charge transporting polymer having a branched structure, the charge transporting polymer having a weight-average molecular weight of 20,000 or greater, and, when a solution containing the charge transporting polymer and toluene at a concentration of 10% by mass of the charge transporting polymer is prepared, the viscosity of the solution at room temperature is less than 3.0 mPa·s. The organic electronic material according to claim 1, wherein the charge transporting polymer contains trivalent or higher-valent structural units, and the content of the trivalent or higher-valent structural units is 17 mol% or less based on all structural units. The organic electronic material as described in claim 2, wherein the charge transport polymer further contains a divalent structural unit and a monovalent structural unit. The organic electronic material according to any one of claims 1 to 3, wherein the charge transporting polymer comprises a structural unit comprising at least one structure selected from the group consisting of an aromatic amine structure, a carbazole structure, a thiophene structure, a fluorene structure, a benzene structure, a pyrrole structure, an aniline structure, and a phenoxazine structure. The organic electronic material according to any one of claims 1 to 4, wherein the charge transporting polymer has at least one polymerizable functional group. The organic electronic material according to any one of claims 1 to 5, wherein the charge transporting polymer is a hole transporting polymer. A liquid composition comprising: the organic electronic material as described in any one of items 1 to 6 of the patent application; and a solvent. An organic layer is formed using the organic electronic material as described in any one of claims 1 to 6, or the liquid composition as described in claim 7. An organic electronic device includes the organic layer as described in claim 8. An organic electroluminescent element comprises the organic layer as described in claim 8. An organic electroluminescent element includes the organic layer described in claim 8 as a hole injection layer or a hole transport layer. A display element comprises the organic electroluminescent element as described in claim 10 or 11. A lighting device includes the organic electroluminescent element as described in claim 10 or 11. A display device comprises: the lighting device as described in claim 13; and a liquid crystal element as a display component. A method for manufacturing an organic electronic element comprises forming an organic layer using the organic electronic material as described in any one of claims 1 to 6 or the liquid composition as described in claim 7.

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