CN117296451A - Method for manufacturing organic semiconductor element - Google Patents

Method for manufacturing organic semiconductor element Download PDF

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Publication number
CN117296451A
CN117296451A CN202280031351.1A CN202280031351A CN117296451A CN 117296451 A CN117296451 A CN 117296451A CN 202280031351 A CN202280031351 A CN 202280031351A CN 117296451 A CN117296451 A CN 117296451A
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group
ring
substituent
solvent
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保科诚
大岛优记
李延军
沈君伟
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Mitsubishi Chemical Corp
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/15—Hole transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/12—Deposition of organic active material using liquid deposition, e.g. spin coating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G61/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G61/12—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/02—Polyamines
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/10—Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/40—Thermal treatment, e.g. annealing in the presence of a solvent vapour
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G2261/30—Monomer units or repeat units incorporating structural elements in the main chain
    • C08G2261/31—Monomer units or repeat units incorporating structural elements in the main chain incorporating aromatic structural elements in the main chain
    • C08G2261/316—Monomer units or repeat units incorporating structural elements in the main chain incorporating aromatic structural elements in the main chain bridged by heteroatoms, e.g. N, P, Si or B
    • C08G2261/3162—Arylamines
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G2261/50—Physical properties
    • C08G2261/51—Charge transport
    • C08G2261/512—Hole transport

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
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  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electroluminescent Light Sources (AREA)
  • Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)

Abstract

The present invention relates to a method for manufacturing an organic semiconductor element, comprising the steps of: a step of applying a first composition and heating to provide a first functional film; a step of applying a second composition to the first functional film, wherein the second composition contains a first functional material, and the first functional material contains an aromatic amine polymer having a weight average molecular weight of 15000 or more and 50000 or less, and does not contain any one of a crosslinking group, a polymerization group, and a leaving soluble group, and the second composition contains a solvent, and the viscosity at 23 ℃ is 15mpa·s or less, and the solvent contains at least one first solvent component having a viscosity at 23 ℃ of 3mpa·s or more.

Description

Method for manufacturing organic semiconductor element
Technical Field
The present invention relates to a method for manufacturing an organic semiconductor element suitable for forming a functional film, wherein the functional film is an organic film made of a functional material.
Background
As the organic semiconductor element, there is an organic electroluminescent element, an organic transistor, or the like. Among them, as a method for producing an organic electroluminescent element, a method of forming a film of an organic material by a vacuum vapor deposition method and laminating the film is generally used. In contrast, in recent years, as a manufacturing method having more excellent material use efficiency, a manufacturing method using a wet film forming method of forming a film of a solubilized organic material by an inkjet method or the like and laminating the film has been actively studied.
In order to form an organic electroluminescent element by laminating a plurality of layers by wet film formation, it is necessary to make the coated film insoluble with respect to the composition coated on the upper layer. In general, the most stable method is a method in which a composition is provided with a crosslinking group or a polymerization group, and a bond is formed by a treatment after coating to be insoluble.
However, it is known that if a light-emitting layer is laminated on a hole-transporting layer made of a functional material having a crosslinking group or a polymeric group, the lifetime of a blue element or the light-emitting efficiency of a blue/green element is adversely affected in particular.
For example, patent document 1 discloses, as a method of insolubilizing a semiconductor material using a semiconductor material containing no crosslinking group or polymeric group, the following method: the insoluble portion is partially insoluble by one or more of heat, vacuum and external air drying, and only the insoluble portion is used for washing to remove the dissolved remainder.
Patent document 2 discloses the following method: the polymer laminated as a semiconductor material is partially insoluble by heating at a temperature higher than its glass transition temperature.
Patent document 3 discloses that the charge transport layer can be made insoluble even if the crosslinkable group is not present by heating, electromagnetic wave irradiation, and particularly UV irradiation of the charge transport layer.
Patent document 4 discloses a method in which a thermally dissociable and soluble group is dissociated by a chemical change caused by heat to be insoluble.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2005-537628
Patent document 2: japanese patent laid-open publication No. 2013-065564
Patent document 3: japanese patent application laid-open No. 2014-212126
Patent document 4: japanese patent application laid-open No. 2010-059417
Disclosure of Invention
Problems to be solved by the invention
However, the method of insolubilizing a semiconductor material using a semiconductor material containing no crosslinking group or no polymer group as disclosed in patent document 1 does not achieve complete insolubilization. The method disclosed in patent document 2 also envisages that the cleaning of the remainder is not achieved, nor is it achieved that the laminated material itself is completely insoluble.
Patent document 3 also envisages the use of a cleaning remainder, but partial dissolution is more suitable for interfacial mixing with the upper layer. However, not only the use of the optical interference is impaired, but also the efficiency and lifetime may be deteriorated in a blue element/phosphorescent green element having a shorter wavelength. In addition, the film thickness of the remaining portion depends on the molecular weight, and in order to obtain a charge transport layer of 20nm, a charge transport material having a weight molecular weight of 30 ten thousand needs to be used. In order to use 2 times of optical interference conditions that can prevent leakage due to foreign matter or high color purity, a film thickness of the charge transport layer of 50 to 150nm is suitable, and it is difficult to form a charge transport layer having a film thickness by this method.
The method disclosed in patent document 4, in which the soluble group is thermally dissociated and is not dissolved by chemical change, may hinder element efficiency in mixing of the dissociated substance into the upper layer.
In general, it is known that a solvent used in a composition constituting an upper layer is effective as an "orthogonal solvent" having low solubility in a material constituting a lower layer. However, in the coated organic electroluminescent element, the two layers of functional materials stacked are similar in structure, and the use of orthogonal solvents is limited.
In addition, if the functional material constituting the lower layer is a material having a molecular weight of several hundred thousand and low solubility, insolubilization becomes easy. However, the use of a functional material having a large molecular weight increases the viscosity of the coating composition, adversely affects the coatability, and restricts the formation of a thick film and the definition of a thick film that require a high-concentration ink.
Further, in the industrialization of manufacturing an organic semiconductor device by wet film formation, more practical insolubilization is required. It is required to perform the insolubilization treatment of the lower layer in a short period of time at a low temperature and to withstand the long-term solvent infiltration required for coating in order to coat a panel having a larger area.
The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a method for producing a semiconductor light-emitting element, which is widely applicable, in the case of forming a functional film containing an organic substance constituting an organic semiconductor element by wet film formation, the functional film being excellent in insolubility when the functional film is provided on the upper layer.
More specifically, the object is to make the organic substance have no crosslinking group, no polymeric group, or no leaving soluble group, and to exhibit a good insolubilizing effect. Further, it is an object of the present invention to provide a method for producing an organic electroluminescent element, which enables lamination of functional materials excellent in luminous efficiency, luminous lifetime and coatability by widely selecting the organic material and the upper layer.
Technical proposal for solving the problems
As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by satisfying specific conditions with a composition as an upper layer thereof even in the case where an organic substance constituting the functional film does not have any one of a crosslinking group, a polymerization group and a leaving soluble group.
Namely, the gist of the present invention is as follows.
[1]
A method for manufacturing an organic semiconductor element, comprising the steps of:
A step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
the first composition contains a first functional material,
the first functional material comprises an aromatic amine polymer having a weight average molecular weight of 15000 or more and 50000, the aromatic amine polymer not having any one of a crosslinking group, a polymerization group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a viscosity of 3 mPas or more at 23 ℃.
[2]
The method for manufacturing an organic semiconductor element according to [1], wherein,
the solvent further comprising a second solvent component having a viscosity of less than 3 mPas at 23 ℃,
the first solvent component has a flow activation energy of 17kJ/mol or more.
[3]
A method for manufacturing an organic semiconductor element, comprising the steps of:
a step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
the first composition contains a first functional material,
The first functional material comprises an aromatic amine polymer without any of a crosslinking group, a polymeric group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a flow activation energy of 17kJ/mol or more,
the solvent also contains a second solvent component having a viscosity of less than 3 mPa-s at 23 ℃.
[4]
The method for producing an organic semiconductor element according to [3], wherein the weight average molecular weight of the aromatic amine polymer is 15000 or more and 50000 or less.
[5]
A method for manufacturing an organic semiconductor element, comprising the steps of:
a step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
the first composition contains a first functional material,
the first functional material comprises an aromatic amine polymer without any of a crosslinking group, a polymeric group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a viscosity of 3 mPas or more at 23 ℃,
The solvent further comprising a second solvent component having a viscosity of less than 3 mPas at 23 ℃,
the first solvent component has a flow activation energy of 17kJ/mol or more.
[6]
The method for producing an organic semiconductor element according to any one of [1] to [5], wherein the aromatic amine polymer has a repeating unit represented by the following formula (50).
[ chemical 1]
(in the formula (50),
Ar 51 represented by the choice of with or withoutA group formed by connecting one group or a plurality of groups of at least one of an aromatic hydrocarbon group and an aromatic heterocyclic group with or without a substituent, wherein the substituent is a crosslinking group, a polymeric group or a leaving soluble group;
Ar 52 represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group with or without a substituent and a divalent aromatic heterocyclic group with or without a substituent, the linking being performed directly or via a linking group, the substituents being each a group other than a crosslinking group, a polymeric group or a leaving soluble group;
Ar 51 and Ar is a group 52 Directly or via a linker to form a ring, or not;
Ar 51 、Ar 52 without any of crosslinking groups, polymeric groups, and leaving soluble groups. )
[7]
The method for producing an organic semiconductor element according to [6], wherein the aromatic amine polymer comprises a structure in which a plurality of benzene ring structures are connected in para-position to a main chain, and at least one of the plurality of benzene ring structures has a substituent at least one of 2 carbon atoms located in the vicinity of a carbon atom bonded to an adjacent benzene ring structure.
[8]
The method for producing an organic semiconductor element according to [6] or [7], wherein the repeating unit represented by the formula (50) is represented by the following formula (54).
[ chemical 2]
(in the formula (54),
Ar 51 ar in the formula (50) 51 The same is true of the fact that,
x is-C (R) 7 )(R 8 )-、-N(R 9 ) -or-C (R) 11 )(R 12 )-C(R 13 )(R 14 )-，
R 1 And R is 2 Each independently is an alkyl group with or without a substituent which is a crosslinking group, a polymeric group, or a group other than a leaving soluble group,
R 7 ～R 9 and R is 11 ～R 14 Each independently is a hydrogen atom, an alkyl group with or without a substituent, an aralkyl group with or without a substituent, or an aromatic hydrocarbon group with or without a substituent, which are each a crosslinking group, a polymerization group, or a group other than a leaving soluble group,
a and b are each independently integers from 0 to 4,
c is an integer of 1 to 3,
d is an integer of 0 to 4,
at R 1 Where there are plural, plural R' s 1 The same or a different one of the above,
at R 2 Where there are plural, plural R' s 2 The same or different. )
[9]
The method for producing an organic semiconductor element according to [8], wherein a value represented by a+b in the formula (54) is 1 or more.
[10]
The method for producing an organic semiconductor element according to any one of [1] to [9], wherein a hansen solubility parameter δp of the first solvent component satisfies a relationship δp < 7.
[11]
The method for producing an organic semiconductor device according to any one of [1] to [10], wherein 2 minutes or more are required from the time of applying the second composition onto the first functional film until the solvent evaporates.
[12]
The method for producing an organic semiconductor device according to any one of [1] to [11], wherein,
the second composition contains a second functional material different from the first functional material,
the second functional material comprises a low molecular aromatic compound having a molecular weight of less than 2000.
[13]
The method for manufacturing an organic semiconductor element according to any one of [1] to [12], wherein the first functional film is a hole transport layer and the second functional film is a light emitting layer.
[14]
The method for producing an organic semiconductor element according to any one of [1] to [13], wherein the heating in the step of providing the first functional film is performed at a temperature lower than the glass transition temperature of the aromatic amine polymer.
[15]
According to [1]]～[14]The method for producing an organic semiconductor device according to any one of the preceding claims, wherein the first solvent component has a theoretical surface area calculated from a COSMO-RS solvation modelVolume->And a boiling point (. Degree.C.) and a viscosity at 23℃of mPa.s satisfy the following relation (A):
32 Xviscosity-4.3 Xtheoretical surface area +5.4 Xvolume-boiling point >150 … (A).
[16]
The method for producing an organic semiconductor device according to any one of [1] to [15], wherein the total content of the first solvent components in the second composition is 15 mass% or more.
[17]
The method for manufacturing an organic semiconductor element according to any one of [1] to [16], wherein the first solvent component contains an aromatic hydrocarbon structure.
Effects of the invention
In the case of forming a functional film containing an organic substance constituting an organic semiconductor element by wet film formation, the present invention can form another film on the functional film without using an organic substance having a crosslinking group, a polymeric group, and a leaving soluble group and being insoluble by a post-coating treatment. Since the organic substance contained in the functional film can be widely selected, and the composition of other films forming the upper layer can be widely selected, for example, a method for manufacturing an organic electroluminescent element can be provided, which enables lamination of functional materials excellent in luminous efficiency, luminous lifetime, and coatability when the organic semiconductor element is an organic electroluminescent element.
Drawings
Fig. 1 is a schematic cross-sectional view showing an example of a structure of a general organic electroluminescent device.
Reference numerals
1. Substrate board
2. Anode
3. Hole injection layer
4. Hole transport layer
5. Light-emitting layer
6. Hole blocking layer
7. Electron transport layer
8. Electron injection layer
9. Cathode electrode
10. Organic electroluminescent element
Detailed Description
The present inventors have found that the above problems can be solved by using any one of the following production methods (a) to (c).
(a) A method for manufacturing an organic semiconductor element, comprising the steps of: a step of applying a first composition and heating to provide a first functional film; a step of applying a second composition to the first functional film to provide a second functional film, wherein the first composition contains a first functional material containing an aromatic amine polymer having a weight average molecular weight of 15000 or more and 50000, the aromatic amine polymer having no crosslinking group, no polymerization group, or no leaving soluble group, and the second composition contains a solvent having a viscosity of 15mpa·s or less at 23 ℃, and at least one first solvent component having a viscosity of 3mpa·s or more at 23 ℃.
(b) A method for manufacturing an organic semiconductor element, comprising the steps of: a step of applying a first composition and heating to provide a first functional film; a step of applying a second composition to the first functional film, the first composition containing a first functional material containing an aromatic amine polymer having no crosslinking group, no polymerization group, or no leaving soluble group, the second composition containing a solvent having a viscosity of 15mpa·s or less at 23 ℃, the solvent containing at least one first solvent component having a flow activation energy of 17kJ/mol or more, and the solvent further containing a second solvent component having a viscosity of less than 3mpa·s at 23 ℃.
(c) A method for manufacturing an organic semiconductor element, comprising the steps of: a step of applying a first composition and heating to provide a first functional film; a step of applying a second composition to the first functional film, the first composition containing a first functional material containing an aromatic amine polymer having no crosslinking group, no polymerization group, or no leaving soluble group, the second composition containing a solvent having a viscosity of 15mpa·s or less at 23 ℃, the solvent containing at least one first solvent component having a viscosity of 3mpa·s or more at 23 ℃, the solvent further containing a second solvent component having a viscosity of less than 3mpa·s at 23 ℃, and the first solvent component having a flow activation energy of 17kJ/mol or more.
According to the production method of the present embodiment, since the aromatic amine polymer does not have a crosslinking group, a polymerization group, or a leaving-soluble group as an organic substance and is insoluble by a treatment after coating, the adverse effect on the lifetime of the device or on the light-emitting efficiency in the case of an organic electroluminescent device can be reduced, and an organic semiconductor device having a functional film excellent in light-emitting efficiency or light-emitting lifetime can be realized. Further, since the aromatic amine polymer does not have any one of a crosslinking group, a polymerization group, and a leaving soluble group, a polymer having a small molecular weight capable of suppressing an increase in viscosity due to concentration is used as a functional material, and coating and heating are performed, whereby a first functional film can be obtained.
The second composition constituting the second functional film has a viscosity of 15mpa·s or less at 23 ℃, and contains the first solvent component having a viscosity of 3mpa·s or more at 23 ℃, or contains the first solvent component having a flow activation energy of 17kJ/mol or more and the second solvent component having a viscosity of less than 3mpa·s at 23 ℃, so that even when the first functional film as the lower layer does not have any one of a crosslinking group, a polymerization group, and a leaving soluble group, dissolution of the first functional film and degradation of performance due to mixing of the dissolved component into the second functional film can be prevented at industrially required dipping time.
According to the method for producing the first composition and the second composition of the present embodiment, when the first functional film is formed by using the first functional material which does not include a structure that deteriorates the characteristics, and further coating the second composition on the film, the dissolution of the first functional material and the mixing of the second functional film can be prevented, and the characteristics can be improved. The structure that deteriorates the characteristics, which means the emission characteristics when the organic semiconductor element is an organic electroluminescent element, is a crosslinking group, a polymeric group, or a leaving-soluble group.
In addition, according to the above manufacturing method, the insoluble durability of the first functional material for a long period of time can be achieved, so that the coating onto the large substrate becomes easy.
As other effects, there are: when forming the second functional film with high purity, the heating condition (temperature/time) conventionally performed for insolubilization can be relaxed without cleaning after forming the first functional film. Further, even if the first functional material is reduced in molecular weight, the influence of deterioration of the insoluble durability characteristic associated with the first functional material can be suppressed. Thus, the following effects can be obtained: the use of a material having a small molecular weight as the first functional material can achieve the effect of a process in which the viscosity of the first composition is easily increased, such as high definition or thick film lamination.
The present invention will be described in detail below with reference to specific examples, but the present invention is not limited to these specific examples.
< first functional film, second functional film >
The first functional film is a film obtained by applying and heating the first composition, and the second functional film is formed on the film. As the first functional film, in the case of the organic electroluminescent element shown in fig. 1, for example, there may be mentioned: a hole injection layer 3 formed on the anode 2, or a hole transport layer 4 formed on the hole injection layer 3.
The second functional film is a functional film obtained by coating a second composition on the surface of the first functional film. In the case of the organic electroluminescent element shown in fig. 1, examples thereof include: a hole transport layer 4 formed on the hole injection layer 3, or a light emitting layer 5 formed on the hole transport layer 4.
< first composition >
The first composition contains a first functional material containing an aromatic amine polymer without any of a crosslinking group, a polymeric group, and a leaving soluble group. In addition, a solvent (organic solvent) is also usually contained.
The first composition may contain one kind of the above aromatic amine polymer as the first functional material, or may contain two or more kinds of the above aromatic amine polymers in any combination and in any ratio.
The first composition may have a functional material other than the first functional material, and examples thereof include: an electron-accepting compound, a charge-transporting material, and the like, which will be described later.
< first functional Material >
The first functional material is an aromatic amine polymer having no any one of a crosslinking group, a polymerization group, and a leaving soluble group, for example, a polymer having a repeating unit represented by the following formula (50).
[ chemical 3]
(in the formula (50),
Ar 51 represents a group formed by linking one group or a plurality of groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, the substituents being eachA crosslinking group, a polymeric group, or a group other than a leaving soluble group.
Ar 52 And represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent, the linking being performed directly or via a linking group, and the substituents being groups other than a crosslinking group, a polymeric group or a leaving soluble group.
Ar 51 And Ar is a group 52 The rings may be formed directly or via a linker bond.
Ar 51 、Ar 52 Without any of crosslinking groups, polymeric groups, and leaving soluble groups. )
(crosslinking group)
The aromatic amine polymer used in the first functional material does not have any one of a crosslinking group, a polymerization group, and a leaving soluble group.
Here, the crosslinking group means a group which reacts with other crosslinking groups located in the vicinity of the crosslinking group by irradiation with heat and/or active energy rays to generate a new chemical bond. In this case, the reactive group is sometimes the same group as the crosslinking group or a different group.
The crosslinking group is not limited, and examples thereof include: an alkenyl group-containing group, a conjugated diene structure-containing group, an alkynyl group, an ethylene oxide structure-containing group, an oxetane structure-containing group, an aziridine structure-containing group, an azide group, a maleic anhydride structure-containing group, an alkenyl group bonded to an aromatic ring, a cyclobutene ring fused to an aromatic ring, and the like. Specific examples of the crosslinking group include: a group selected from the following crosslinking group T.
(crosslinking group T)
[ chemical 4]
[ chemical 5]
In the above crosslinking group T, R 3 Represents an alkyl group having 1 to 4 carbon atoms. From the viewpoint of easy formation of oxetane ring, R 3 Methyl and ethyl are particularly preferred. R is R XL Represents a methylene group, an oxygen atom or a sulfur atom, n XL An integer of 0 to 5. There are a plurality of R XL In the case where they are identical or different, there are a plurality of n XL When they are identical, they may be different. * And 1 represents a bonding position. These crosslinking groups may have a substituent.
(polymeric group)
The polymeric group not possessed by the aromatic amine polymer used in the first functional material means a functional group that undergoes a polymerization reaction in a reaction that normally proceeds to polymerize a monomer to obtain a polymer.
(leaving soluble group)
The leaving soluble group not possessed by the aromatic amine polymer used in the first functional material means a group exhibiting solubility to a solvent, and means a group thermally dissociated from a bonded group (e.g., hydrocarbon ring) at a specific temperature or higher (e.g., 70 ℃ or higher). By such dissociation of the leaving soluble group, the solubility of the polymer to the solvent decreases.
Examples of the leaving soluble group include: JP-A2010-059417 describes "a thermally dissociable, soluble group".
(Ar 52 : a main chain
Ar in the repeating unit represented by the above formula (50) 52 Represents a group formed by linking one group or a plurality of groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent. When selected groups are linked, they may be directly linked or linked via a linker. Here, the substituent which the aromatic hydrocarbon group and the aromatic heterocyclic group may have is a substituent other than a crosslinking group, a polymeric group or a leaving soluble group The same group as substituent group Z described later is preferable. In the present specification, a crosslinking group, a polymeric group, and a leaving-soluble group may be collectively referred to as "a crosslinking group or the like".
The aromatic hydrocarbon group preferably has 6 or more and 60 or less carbon atoms, and specifically includes: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring,A divalent group of a six-membered ring such as a ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring, or a divalent group of a two-to-five-membered condensed ring, or a group obtained by connecting a plurality of these groups. When the plural groups are linked, there may be mentioned 2 to 10 divalent groups linked, preferably 2 to 5 divalent groups linked. By the term "divalent group of a benzene ring" is meant "benzene ring having a divalent free valence", that is, phenylene ".
The aromatic heterocyclic group preferably has 3 or more and 60 or less carbon atoms, and specifically includes: a divalent group of a five-membered or a two-to four-membered fused ring such as a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiazole ring, a benzoimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a pyridine ring, a quinazoline ring, a quinazolinone ring, an azulene ring, or a plurality of them. When a plurality of the groups are linked, the divalent group is preferably a divalent group in which 2 to 10 groups are linked, and more preferably a divalent group in which 2 to 5 groups are linked.
The divalent group in which a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic heterocyclic groups which may have a substituent are directly or via a linking group may be a group in which a plurality of the same groups are linked, or may be a group in which a plurality of different groups are linked. The plural groups are preferably divalent groups in which 2 to 10 groups are bonded, and more preferably divalent groups in which 2 to 5 groups are bonded.
(Ar 51 : side chain
Ar in the repeating unit represented by the above formula (50) 51 Represents a group formed by linking one group or a plurality of groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent. The substituents which the aromatic hydrocarbon group and the aromatic heterocyclic group may have are a crosslinking group, a polymeric group or a substituent other than a leaving soluble group, and are preferably the same groups as the substituent group Z described later.
The aromatic hydrocarbon group preferably has 6 or more and 60 or less carbon atoms, and specifically includes: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring,A monovalent group of a six-membered ring such as a ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring, or a two-to-five-membered condensed ring, or a group obtained by connecting a plurality of these groups. When the plurality of groups are linked, a monovalent group formed by linking 2 to 10 groups, preferably a monovalent group formed by linking 2 to 5 groups, may be mentioned. For example, "monovalent group of benzene ring" means "benzene ring having monovalent free valence", that is, phenyl group ".
The aromatic heterocyclic group preferably has 3 or more and 60 or less carbon atoms, and specifically includes: a monovalent group of a five-membered or a two-to four-membered fused ring such as a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiazole ring, a benzoimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a pyridine ring, a quinazoline ring, a quinazolinone ring, an azulene ring, or a group formed by connecting a plurality of them. When a plurality of the groups are linked, the monovalent group is preferably a monovalent group in which 2 to 10 groups are linked, and more preferably a monovalent group in which 2 to 5 groups are linked.
The monovalent group formed by connecting a plurality of aromatic hydrocarbon groups which may have a substituent or aromatic heterocyclic groups which may have a substituent may be a group formed by connecting a plurality of the same groups or a group formed by connecting a plurality of different groups. The plurality of linking groups is preferably a monovalent group in which 2 to 10 groups are linked, and more preferably a monovalent group in which 2 to 5 groups are linked.
Ar is excellent in charge transport property and durability 51 Among them, a monovalent group of a benzene ring or a fluorene ring which may have a substituent other than a crosslinking group or the like, that is, a phenyl group or a fluorenyl group which may have a substituent other than a crosslinking group or the like is more preferable, and a 2-fluorenyl group which may have a substituent other than a crosslinking group or the like is particularly preferable.
As Ar 51 The substituent other than the crosslinking group and the like that the aromatic hydrocarbon group and the aromatic heterocyclic group may have is not particularly limited as long as it is a substituent that does not significantly deteriorate the characteristics of the present polymer. The substituent is preferably a group selected from the substituent group Z described below, more preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group, and still more preferably an alkyl group.
Ar from the aspect of solubility in a coating solvent 51 The fluorenyl group is preferably substituted with an alkyl group having 1 to 24 carbon atoms, and particularly preferably a 2-fluorenyl group substituted with an alkyl group having 4 to 12 carbon atoms. Further preferred is a 9-alkyl-2-fluorenyl group substituted at the 9-position with an alkyl group, and particularly preferred is a 9,9' -dialkyl-2-fluorenyl group disubstituted with an alkyl group.
By the fluorenyl group substituted with the alkyl group in at least one of the positions 9 and 9', there is a tendency to improve the solubility of the solvent and the durability of the fluorene ring. Further, the fluorenyl group substituted with the alkyl group at both the 9-position and the 9' -position tends to further improve the solubility in a solvent and the durability of the fluorene ring.
In addition, in the case of the optical fiber, ar from the aspect of solubility in a coating solvent 51 Spirobifluorenyl is also preferred.
In addition, ar 51 Can be combined with Ar 52 Directly or via a linker to form a ring.
(content of repeating units represented by the formula (50))
The content of the repeating unit represented by the formula (50) in the polymer contained in the first functional film is not particularly limited, but the repeating unit represented by the formula (50) is usually contained in the polymer in an amount of 10 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and still more preferably 50 mol% or more.
The repeating unit of the polymer contained in the first functional film may be composed of only the repeating unit represented by the formula (50), that is, may be 100 mol%, but may have a repeating unit different from the formula (50) for the purpose of balancing the performances as an organic electroluminescent element. In this case, the content of the repeating unit represented by the formula (50) in the polymer is usually 99 mol% or less, preferably 95 mol% or less.
(terminal group)
In the present specification, the terminal group means a structure of a terminal portion of a polymer formed from a capping agent used at the end of polymerization of the polymer. In the first functional film, the terminal group of the polymer including the repeating unit represented by formula (50) is preferably a hydrocarbon group. The hydrocarbon group is preferably a hydrocarbon group having 1 to 60 carbon atoms, more preferably a hydrocarbon group having 1 to 40 carbon atoms, and still more preferably a hydrocarbon group having 1 to 30 carbon atoms, from the viewpoint of charge transport property.
Examples of the hydrocarbon group include the following groups.
Straight-chain, branched or cyclic alkyl groups having not less than 1, preferably not less than 4, usually not more than 24, preferably not more than 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl and dodecyl groups;
a linear, branched or cyclic alkenyl group having not less than 2 and not more than 24, preferably not more than 12, carbon atoms such as a vinyl group;
straight-chain or branched alkynyl groups having not less than 2 and not more than 24, preferably not more than 12, carbon atoms such as ethynyl;
an aromatic hydrocarbon group having 6 to 36 carbon atoms, preferably 24 carbon atoms, such as a phenyl group and a naphthyl group.
These hydrocarbon groups may have a substituent, and the substituent may be preferably an alkyl group or an aromatic hydrocarbon group. When a plurality of these substituents may be provided, they may be bonded to each other to form a ring.
From the viewpoints of charge transport property and durability, the terminal group is preferably an alkyl group or an aromatic hydrocarbon group, and more preferably an aromatic hydrocarbon group.
(substituent group Z)
The substituent group Z is a group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an aralkylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group and an aromatic heterocyclic group. These substituents may comprise any of linear, branched, and cyclic structures.
The substituent group Z may more specifically have the following structure.
A linear, branched or cyclic alkyl group having 1 or more, preferably 4 or more and 24 or less, preferably 12 or less, more preferably 8 or less, and still more preferably 6 or less. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, dodecyl, and the like.
An alkoxy group having 1 to 24 carbon atoms, preferably 12 carbon atoms. Specific examples include: methoxy, ethoxy, and the like.
An aryloxy group or a heteroaryloxy group having 4 or more carbon atoms, preferably 5 or more carbon atoms and 36 or less carbon atoms, preferably 24 or less carbon atoms. Specific examples include: phenoxy, naphthoxy, pyridyloxy, and the like.
An alkoxycarbonyl group having 2 to 24 carbon atoms, preferably 12 carbon atoms. Specific examples include: methoxycarbonyl, ethoxycarbonyl, and the like.
A dialkylamino group having 2 to 24 carbon atoms, preferably 12 carbon atoms. Specific examples include: dimethylamino, diethylamino, and the like.
A diarylamino group having 10 or more carbon atoms, preferably 12 or more and 36 or less carbon atoms, and preferably 24 or less carbon atoms. Specific examples include: diphenylamino, xylylamino, N-carbazolyl, and the like.
Aralkylamino groups having 7 to 36 carbon atoms, preferably 24 or less. Specific examples include: phenylmethylamino.
An acyl group having 2 to 24 carbon atoms, preferably 12 carbon atoms. Specific examples include: acetyl, benzoyl.
Halogen atoms such as fluorine atom and chlorine atom;
Haloalkyl having 1 to 12 carbon atoms, preferably 6 or less. Specific examples include: trifluoromethyl, and the like.
Alkylthio groups having 1 to 24 carbon atoms, preferably 12 carbon atoms. Specific examples include: methylthio, ethylthio, and the like.
An arylthio group having 4 or more carbon atoms, preferably 5 or more and 36 or less carbon atoms, preferably 24 or less carbon atoms. Specifically, there may be mentioned: phenylthio, naphthylthio, pyridylthio, and the like.
The number of carbon atoms is usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less. Specific examples include: trimethylsilyl, triphenylsilyl, and the like.
Siloxy groups having 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less carbon atoms. Specific examples include: trimethylsiloxy, triphenylsiloxy, and the like.
Cyano groups.
An aromatic hydrocarbon group having 6 to 36 carbon atoms, preferably 24 carbon atoms. Specific examples include: phenyl, naphthyl, and the like.
An aromatic heterocyclic group having 3 or more carbon atoms, preferably 4 or more and 36 or less carbon atoms, preferably 24 or less carbon atoms. Specific examples include: thienyl, pyridyl, and the like.
The above substituents may comprise any of linear, branched or cyclic structures.
Among the above substituent groups Z, alkyl groups, alkoxy groups, aromatic hydrocarbon groups, aromatic heterocyclic groups are preferable. From the viewpoint of charge transport properties, it is further preferable that the compound has no substituent.
Each substituent of the substituent group Z may have a substituent. Examples of the substituent include the same substituents as those in the substituent group Z. The substituent that may be provided is preferably an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms, or a phenyl group. From the viewpoint of charge transport properties, it is more preferable that the polymer has no substituent.
(preferred Ar) 51 )
In addition, ar in the repeating unit represented by the above formula (50) is preferable as the polymer 51 Is a group represented by the following formula (51), the following formula (52) or the following formula (53).
(preferred Ar) 51 : (51)
[ chemical 6]
(in the formula (51),
* Represents a bond to N of the main chain of formula (50),
Ar 53 、Ar 54 each independently represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, either directly or via a linking group Grafting is carried out.
Ar 55 Represents a monovalent group formed by linking one or more groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, the linking being performed directly or via a linking group.
Ar 56 Represents a hydrogen atom or a substituent. )
Here, each aromatic hydrocarbon group and each aromatic heterocyclic group may have a substituent, ar when substituted 56 Is a substituent other than a crosslinking group or the like.
(Ar 53 、Ar 54 )
Ar in the group represented by the formula (51) 53 、Ar 54 Each independently represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent, and the linking is performed directly or via a linking group.
The group is preferably a group in which a plurality of divalent aromatic hydrocarbon groups which may have a substituent or divalent aromatic hydrocarbon groups which may have a substituent are linked. Here, the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have is a substituent other than a crosslinking group or the like, and is preferably the same group as the substituent group Z.
Ar 53 And Ar is a group 54 Aromatic hydrocarbon groups and aromatic heterocyclic groups of (C), and Ar may be used as the above 52 The same aromatic hydrocarbon group and aromatic heterocyclic group.
The divalent group formed by connecting a plurality of groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent directly or via a linking group may be a group formed by connecting a plurality of the same groups or a group formed by connecting a plurality of different groups.
When a plurality of divalent groups are bonded, the divalent group is preferably a divalent group in which 2 to 10 groups are bonded, and preferably a divalent group in which 2 to 5 groups are bonded.
Ar 53 Preferably, the divalent aromatic hydrocarbon group which may have a substituent is 1 orThe group having 2 to 6 substituents is more preferably a group having 1 or 2 to 4 substituents as a divalent aromatic hydrocarbon group, and among them, a group having 1 or 2 to 4 substituents as a phenylene ring is more preferred, and a biphenyl group having 2 substituents as a phenylene ring is particularly preferred.
When a plurality of these divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are linked, the divalent aromatic hydrocarbon groups to which the plurality of divalent aromatic hydrocarbon groups are linked are preferably groups bonded so as not to be conjugated. Specifically, a group containing a 1, 3-phenylene group or a group having a substituent and having a twisted structure due to a steric effect of the substituent is preferable.
Ar 53 The substituent that may be provided is a substituent other than a crosslinking group or the like, and is preferably the same group as the substituent group Z. Preferably Ar 53 Has no substituent.
Ar is excellent in charge transport property and durability 54 The divalent aromatic hydrocarbon group is preferably a group in which 1 or more divalent aromatic hydrocarbon groups which are the same or different are bonded, and the divalent aromatic hydrocarbon group may have a substituent. The number of divalent aromatic hydrocarbon groups at the time of the plural connection is preferably 2 or more and 10 or less, more preferably 6 or less, and particularly preferably 3 or less from the viewpoint of the stability of the film.
Preferred aromatic hydrocarbon structures include benzene rings, naphthalene rings, anthracene rings, and fluorene rings, and more preferably benzene rings and fluorene rings.
The plurality of groups to be bonded are preferably groups in which 2 to 4 phenylene rings which may have a substituent are bonded or groups in which a phenylene ring which may have a substituent is bonded to a fluorene ring which may have a substituent. Further, 1 phenylene ring which may have a substituent is also preferable. From the viewpoint of LUMO extension, a biphenylene group in which 2 phenylene rings which may have a substituent are linked is particularly preferable.
As Ar 54 Any one of the substituent groups Z, or a combination thereof may be used as the substituent groups which may be provided. The substituent is preferably N-carbazolyl and indolylGroups other than the indolocarbazolyl group and the indenocarbazolyl group are phenyl, naphthyl and fluorenyl groups as more preferable substituents. In addition, it is also preferable that the compound has no substituent.
(Ar 55 )
Ar 55 Represents a monovalent group formed by linking one or more groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, the linking being performed directly or via a linking group. The monovalent aromatic hydrocarbon group which may have a substituent or a group in which a plurality of monovalent aromatic hydrocarbon groups which may have a substituent are bonded is preferable.
Here, the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have is a substituent other than a crosslinking group or the like, and is preferably the same group as the substituent group Z.
When at least one group selected from the aromatic hydrocarbon group and the aromatic heterocyclic group is bonded to a plurality of groups, a monovalent group in which 2 to 10 groups are bonded is preferable, and a monovalent group in which 2 to 5 groups are bonded is more preferable.
As the aromatic hydrocarbon group or aromatic heterocyclic group, those mentioned for Ar can be used 51 The same aromatic hydrocarbon group and aromatic heterocyclic group.
As Ar 55 It is preferable to have a structure represented by any one of the following routes 2. Further, from the viewpoint of the LUMO distribution of the molecule, the structure is preferably selected from the group consisting of a-1 to a-4, b-1 to b-9, c-1 to c-4, d-1 to d-16 and e-1 to e-4 shown in the following scheme 2.
Further, from the viewpoint of promoting the LUMO extension of the molecule by having an electron withdrawing group, a structure selected from a-1 to a-4, b-1 to b-9, d-1 to d-12 and e-1 to e-4 is preferable. Further, from the viewpoint of the effect of confining excitons formed in the light-emitting layer when the second functional film is used as the light-emitting layer, which is high in triplet energy level, a structure selected from a-1 to a-4, d-1 to d-12, and e-1 to e-4 is preferable.
Further, d-1 and d-10 are more preferable, and a benzene ring structure of d-1 is particularly preferable, from the viewpoint of easy synthesis and excellent stability.
Further toThese may have a substituent on the structure. In the structural formula, "-" represents Ar 54 When "-" has plural bonding positions, any one of these represents Ar 54 Is used for the bonding position of the substrate.
[ chemical 7]
[ chemical 8]
(R 31 And R is 32 )
R of scheme 2 31 And R is 32 Each independently is preferably a linear, branched or cyclic alkyl group which may have a substituent. The number of carbon atoms of the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 to 6, more preferably 3 or less, and further preferably methyl or ethyl.
R 31 And R is 32 Identical or different, in R 31 And R is 32 When there are a plurality of the groups, these groups may be the same or different, but all of R are preferable in terms of being capable of uniformly distributing charges around the nitrogen atom and being easy to synthesize 31 And R is 32 Are the same groups.
As Ar 55 Any one or a combination of the substituents mentioned above may be used as the substituent group Z. From the viewpoints of durability and charge transport properties, it is preferably selected from Ar as described above 54 The substituents may have the same substituent.
(Ar 56 )
Ar 56 Represents a hydrogen atom or a substituent. Ar (Ar) 56 The substituent is not particularly limited, but an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent is preferable. As a preferable structure, it is a structure similar to the Ar 53 、Ar 54 The monovalent structures of the aromatic hydrocarbon structure and the aromatic heterocyclic structure are the same as each other.
Ar 56 When substituted, the group is not a crosslinking group or the like.
Ar 56 In the case of a substituent, it is preferable to bond to the 3 rd position of carbazole from the viewpoint of improvement in durability. Further, from the viewpoints of improvement in durability and charge transport property, an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent is preferable, and an aromatic hydrocarbon group which may have a substituent is more preferable.
Ar from the viewpoints of easiness of synthesis and charge transport property 56 Preferably a hydrogen atom.
As Ar 56 The substituents in the case of the aromatic hydrocarbon group which may have a substituent or the aromatic heterocyclic group which may have a substituent are the same as those listed in the substituent group Z, and the preferred substituents are the same, and the substituents may be the same.
(preferred Ar) 51 : (52)
Ar in the repeating unit represented by the above formula (50) 51 Also preferably, at least one of them is a group represented by the following formula (52). The reason for this is considered that in the two carbazole structures in the following formula (52), the influence on the main chain amine in the formula (50) is suppressed by the aromatic hydrocarbon group or the aromatic heterocyclic group having LUMO distributed between two nitrogen atoms, and the durability against electrons or excitons of the main chain amine is improved.
[ chemical 9]
(in the formula (52),
Ar 61 and Ar is a group 62 Each independently represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent, and the linking is performed directly or via a linking group.
Ar 63 ～Ar 65 Each of which is a single pieceIndependently a hydrogen atom or a substituent.
* Represents a bonding position to a nitrogen atom in the formula (50). )
However, each aromatic hydrocarbon group and each aromatic heterocyclic group may have a substituent, and Ar when substituted 63 ～Ar 65 Is a substituent other than a crosslinking group or the like.
(Ar 63 ～Ar 65 )
Ar 63 ～Ar 65 Ar in formula (51) each independently of 56 The same applies.
(Ar 62 )
Ar 62 Represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent, the linking being performed directly or via a linking group. Preferably, the aromatic hydrocarbon group is a divalent aromatic hydrocarbon group which may have a substituent or a group formed by connecting divalent aromatic hydrocarbon groups which may have a substituent.
Ar 62 Ar in the formula (51) 54 The same applies.
Ar 62 Specifically, the preferable group is a benzene ring, naphthalene ring, anthracene ring, divalent group of fluorene ring or a group formed by connecting a plurality of them, more preferably a divalent group of benzene ring, divalent group of fluorene ring or a group formed by connecting a plurality of them, particularly preferably a 1, 4-phenylene group formed by connecting benzene ring with divalent position 1,4, a 2, 7-fluorenylene group formed by connecting 2, 7-position of fluorene ring or a group formed by connecting a plurality of them, most preferably a group containing "1, 4-phenylene-2, 7-fluorenylene-1, 4-phenylene-".
In Ar 62 In these preferred structures of (2), when the phenylene group has no substituent other than the linking position, ar is not generated due to the steric effect of the substituent 62 Is preferred. In addition, from the viewpoint of improving solubility and durability of fluorene structure, the fluorenylene group preferably has a substituent at the 9,9' position.
(Ar 61 )
Ar 61 Ar in the formula (52) 53 Identical toThe preferred structures are also the same.
(preferred Ar) 51 : (53)
Ar in the repeating unit represented by the above formula (50) is also preferable 51 Is a group represented by the following formula (53).
[ chemical 10]
(in the formula (53),
* Represents a bond to N of the main chain of formula (50),
Ar 71 represents a divalent aromatic hydrocarbon group which may have a substituent,
Ar 72 and Ar is a group 73 Each independently represents a divalent group formed by linking one group or a plurality of groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, and the linking is performed directly or via a linking group.
Ring HA is an aromatic heterocycle comprising a nitrogen atom, X 2 、Y 2 Each independently represents a C atom or an N atom, X 2 Or Y 2 When the atom is C, the substituent may be present. )
(Ar 71 )
Ar 71 Ar in the formula (51) 53 The same groups.
As Ar 71 The group in which 1 divalent aromatic hydrocarbon group which may have a substituent or 2 to 10 divalent aromatic hydrocarbon groups which may have a substituent are bonded is preferable, and 1 divalent aromatic hydrocarbon group which may have a substituent or 2 to 8 divalent aromatic hydrocarbon groups which may have a substituent are more preferable, and among these, 2 to 6 divalent aromatic hydrocarbon groups which may have a substituent are more preferable.
As Ar 71 Particularly, it is preferably a group in which 2 to 6 benzene rings which may have substituents are linked, and most preferably a tetraphenylene group in which 4 benzene rings which may have substituents are linked.
In addition, ar 71 Preferably, the aromatic hydrocarbon compound contains at least one benzene ring formed by linking at the non-conjugated site, i.e., the 1, 3-position, and more preferably contains two or more benzene rings.
Ar 71 When a plurality of divalent aromatic hydrocarbon groups which may have a substituent are bonded, it is preferable that the groups are bonded directly to each other from the viewpoint of charge transport property or durability.
Thus, as Ar 71 Preferred structures between N linking the backbone of the polymer and the ring HA in formula (53) are listed below. In the following structural formula, one of the two "-" represents a site bonded to N of the main chain of the polymer, and the other represents a site bonded to the cyclic HA of formula (53). Either of the two "-" groups may be bonded to the N of the main chain of the polymer or may be bonded to the cyclic HA.
[ chemical 11]
As Ar 71 Any one or a combination of the substituents mentioned above may be used as the substituent group Z. Ar (Ar) 71 Preferred ranges of substituents which may be present are Ar in formula (51) above 53 The same group, more preferred structure and Ar 53 The preferred groups of (2) are the same.
(X 2 And Y 2 )
X 2 And Y 2 Each independently represents a C (carbon) atom or an N (nitrogen) atom. X is X 2 Or Y 2 When the atom is C, the substituent may be present.
From the standpoint of easier localization of LUMO around ring HA, X 2 、Y 2 N atoms are preferred.
As X 2 Or Y 2 Any one or a combination of the substituents mentioned above for the substituent group Z may be used as the substituent which may be present when the substituent is a C atom. From the viewpoint of charge transport properties, it is further preferable that the compound has no substituent.
(Ar 72 And Ar is a group 73 )
Ar 72 And Ar is a group 73 Each independently represents a divalent group formed by linking one group or a plurality of groups selected from at least one of an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent, the linking being performed directly or via a linking group.
Ar from the viewpoint of the LUMO distribution of the molecules 72 And Ar is a group 73 Each independently preferably having Ar selected from the group consisting of formula (51) 55 The structures a-1 to a-4, b-1 to b-9, c-1 to c-4, d-1 to d-16 and e-1 to e-4 shown in the above-mentioned scheme 2 are the same.
Further, from the viewpoint of promoting the LUMO extension of the molecule by having an electron withdrawing group, a structure selected from a-1 to a-4, b-1 to b-9, c-1 to c-5, d-1 to d-12 and e-1 to e-4 is preferable.
Further, from the viewpoint of the effect of limiting the formation of excitons in the light-emitting layer when the second functional film is used as the light-emitting layer, which is high in triplet energy level, a structure selected from a-1 to a-4, d-1 to d-12, and e-1 to e-4 is preferable.
Further, from the viewpoint of preventing aggregation of molecules, a structure selected from d-1 to d-12 and e-1 to e-4 is more preferable. Ar is excellent in stability from the viewpoint of easy synthesis 72 And Ar is a group 73 Is of the same structure, and is preferably d-1 or d-10, particularly preferably a benzene ring structure of d-1.
In addition, these structures may have a substituent. In the structural formula, "-" represents a bonding site with the ring HA. When "-" HAs a plurality of groups, any one of these groups represents a site bonded to the ring HA.
As Ar 72 And Ar is a group 73 The substituent which may be present may be any one or a combination of the substituents shown above (substituent group Z). From the viewpoints of durability and charge transport property, the substituents other than the crosslinking group and the like are preferably the same groups as the substituent group Z described above.
(preferred backbone)
The aromatic amine polymer having a repeating unit represented by the above formula (50) preferably has a structure in which a plurality of benzene ring structures are connected in para-position on the main chain, and at least one of the plurality of benzene ring structures has a substituent at least one of 2 carbon atoms in the adjacent position to the carbon atom to which the benzene ring structure adjacent to each other is bonded. Either or both of the two benzene ring structures adjacent to each other may be part of a condensed ring. This is because the glass transition temperature of the aromatic amine polymer decreases and the layer becomes easily cured.
The repeating unit represented by the above formula (50) is preferably a repeating unit represented by the following formula (54), a repeating unit represented by the following formula (55), a repeating unit represented by the following formula (56) or a repeating unit represented by the following formula (57), more preferably a repeating unit represented by the following formula (54).
(repeating unit represented by the formula (54))
[ chemical 12]
(in the formula (54),
Ar 51 ar in the above formula (50) 51 The same is true of the fact that,
x is-C (R) 7 )(R 8 )-、-N(R 9 ) -or-C (R) 11 )(R 12 )-C(R 13 )(R 14 )-，
R 1 And R is 2 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like,
R 7 ～R 9 and R is 11 ～R 14 Each independently is a hydrogen atom, an alkyl group which may have a substituent other than a crosslinking group or the like, an aralkyl group which may have a substituent other than a crosslinking group or the like, or an aromatic hydrocarbon group which may have a substituent other than a crosslinking group or the like,
a and b are each independently integers from 0 to 4,
c is an integer of 1 to 3,
d is an integer of 0 to 4,
at R 1 Where there are plural, plural R' s 1 The same or a different one of the above,
at R 2 In the case where there are a plurality of them,multiple R' s 2 The same or different. )
(R 1 、R 2 )
R in the repeating unit represented by the above formula (54) 1 And R is 2 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like.
The alkyl group is a linear, branched or cyclic alkyl group. The number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more, more preferably 8 or less, still more preferably 6 or less, and still more preferably 3 or less, in order to maintain the solubility of the polymer. The alkyl group is further preferably methyl or ethyl.
Where there are a plurality of R 1 In the case of (1), a plurality of R 1 Identical or different, in the presence of a plurality of R' s 2 In the case of (1), a plurality of R 2 The same or different. It should be noted that there are a plurality of R 1 In (2) is an integer of 2 or more, c is an integer of 2 or more, or both, but in either case, a plurality of R's are 1 The same or different. With respect to R 2 Also the same, there are a plurality of R 2 In (2) or more, d is an integer of 2 or more, or both, but in either case, a plurality of R' s 2 The same or different.
All R are preferable in terms of being able to uniformly distribute charges around nitrogen atoms and easy to synthesize 1 And R is 2 Are the same groups.
R 1 、R 2 The alkyl group of (2) may have a substituent other than a crosslinking group or the like. Examples of the substituent other than the crosslinking group include: r is as described below 7 ～R 9 And R is 11 ～R 14 Preferred groups for alkyl, aralkyl and aromatic hydrocarbon groups.
From the viewpoint of voltage reduction, R 1 、R 2 Most preferably the alkyl group of (2) has no substituent.
(R 7 ～R 9 And R is 11 ～R 14 )
R 7 ～R 9 And R is 11 ～R 14 Each independently is a hydrogen atom, an alkyl group which may have a substituent other than a crosslinking group or the like, an aralkyl group which may have a substituent other than a crosslinking group or the like, or an aromatic hydrocarbon group which may have a substituent other than a crosslinking group or the like.
The alkyl group is not particularly limited, but in order to improve the solubility of the polymer, the number of carbon atoms is preferably 1 or more, more preferably 24 or less, still more preferably 8 or less, and still more preferably 6 or less. Further, the alkyl group may have a linear, branched or cyclic structure.
Specific examples of the alkyl group include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, cyclohexyl, dodecyl, and the like.
The aralkyl group is not particularly limited, but in order to be able to improve the solubility of the polymer, the number of carbon atoms is preferably 5 or more, more preferably 60 or less, and still more preferably 40 or less.
Specific examples of the aralkyl group include: 1, 1-dimethyl-1-phenylmethyl, 1-di (n-butyl) -1-phenylmethyl, 1-di (n-hexyl) -1-phenylmethyl, 1-di (n-octyl) -1-phenylmethyl, phenylethyl, 3-phenyl-1-propyl, 4-phenyl-1-n-butyl, 1-methyl-1-phenylethyl, 5-phenyl-1-n-propyl, 6-phenyl-1-n-hexyl, 6-naphthyl-1-n-hexyl, 7-phenyl-1-n-heptyl, 8-phenyl-1-n-octyl, 4-phenylcyclohexyl, and the like.
The aromatic hydrocarbon group is not particularly limited, but in order to improve the solubility of the polymer, the number of carbon atoms is preferably 6 or more, more preferably 60 or less, and still more preferably 30 or less.
Specific examples of the aromatic hydrocarbon group include: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring,A monovalent group of a six-membered ring such as a ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring, or a two-to-five-membered condensed ring, or a group obtained by connecting a plurality of them。
From the viewpoint of improvement of charge transport property and durability, R 7 ～R 9 Preferably methyl or aromatic hydrocarbon radicals, R 7 And R is 8 More preferably methyl, R 9 More preferably phenyl.
R 7 ～R 9 And R is 11 ～R 14 The alkyl group, the aralkyl group and the aromatic hydrocarbon group of (a) may have a substituent other than the crosslinking group. Examples of the substituent other than the crosslinking group include: as R as above 7 ～R 9 And R is 11 ～R 14 Preferred groups for alkyl, aralkyl and aromatic hydrocarbon groups.
From the viewpoint of voltage reduction, R 7 ～R 9 And R is 11 ～R 14 The alkyl group, the aralkyl group and the aromatic hydrocarbon group of (2) most preferably have no substituent.
(a, b, c and d)
In the repeating unit represented by the above formula (54), a and b are each independently an integer of 0 to 4. The value represented by a+b is preferably 1 or more, and further, a and b are each preferably 2 or less, and both a and b are more preferably 1. When c is 1 or more, the structures of a is defined by c phenylene groups and b is 1 or more, and when d is 1 or more, the structures of b are defined by d phenylene groups.
When the value represented by a+b is 1 or more, the aromatic ring of the main chain is distorted by steric hindrance, and the polymer is excellent in solubility in a solvent, and at the same time, the coating film formed by the wet film forming method and heat-treated tends to be excellent in insolubility in a solvent. Therefore, if the value represented by a+b is 1 or more, elution of the polymer such as the aromatic amine polymer contained in the first composition into the second composition containing the organic solvent is suppressed when the second functional film, which is another organic layer, is formed on the first functional film by the wet film forming method. As a result, it is considered that the influence on the second functional film formed is small, and the driving life of the organic semiconductor element is further prolonged.
In the repeating unit represented by the above formula (54), c is an integer of 1 to 3, and d is an integer of 0 to 4. c and d are each preferably 2 or less, more preferably c is equal to d, particularly preferably both c and d are 1, or both c and d are 2.
When both c and d in the repeating unit represented by the above formula (54) are 1 or both c and d are 2 and both a and b are 2 or 1, R is most preferable 1 And R is R 2 Bonded at mutually symmetrical positions.
Here, R is 1 And R is R 2 Bonded at symmetrical positions with respect to each other means R relative to the fluorene ring, carbazole ring or 9, 10-dihydrophenanthrene derivative structure in formula (54) 1 And R is R 2 Is symmetrical in bonding position. At this time, the same structure is considered as a rotation of 180 degrees about the main chain.
(X)
X in the above formula (54) is preferably-C (R) 7 )(R 8 ) -or-N (R) 9 ) -, more preferably-C (R 7 )(R 8 )-。
(preferred repeat units)
The repeating unit represented by the above formula (54) is particularly preferably a repeating unit represented by any one of the following formulas (54-1) to (54-4).
[ chemical 13]
In the above, ar 51 、R 1 、R 2 And X is respectively the same as Ar in formula (54) 51 、R 1 、R 2 Identical to X, but R is preferred 1 And R is 2 Identical, and R 1 And R is R 2 Bonded at mutually symmetrical positions.
(specific example of the main chain of the repeating unit represented by the formula (54))
The main chain structure excluding nitrogen atoms in the above formula (54) is not particularly limited, and examples thereof include the following structures.
[ chemical 14]
[ 15]
[ 16]
[ chemical 17]
[ chemical 18]
[ chemical 19]
[ chemical 20]
(repeating unit represented by the formula (55))
[ chemical 21]
(in the formula (55),
Ar 51 ar in the formula (50) 51 The same is true of the fact that,
R 3 and R is 6 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like,
R 4 and R is 5 Each independently ofAn alkyl group which may have a substituent other than a crosslinking group or the like, an alkoxy group which may have a substituent other than a crosslinking group or the like, or an aralkyl group which may have a substituent other than a crosslinking group or the like,
l is 0 or 1, and the number of the components is 1,
m is 1 or 2, and the number of the m is 1 or 2,
n is 0 or 1, and the number of the N is not limited,
p is either 0 or 1 and,
q is 0 or 1. )
(R 3 、R 6 )
R in the repeating unit represented by the above formula (55) 3 And R is 6 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like.
Examples of the alkyl group include R in the formula (54) 1 And R is 2 The same alkyl group may have a substituent and a preferable structure may be mentioned as R 1 And R is 2 The same substituents and structures.
(R 4 、R 5 )
R in the repeating unit represented by the above formula (55) 4 And R is 5 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like, an alkoxy group which may have a substituent other than a crosslinking group or the like, or an aralkyl group which may have a substituent other than a crosslinking group or the like.
The alkyl group is a linear, branched or cyclic alkyl group. The number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more, more preferably 24 or less, still more preferably 8 or less, and still more preferably 6 or less, in order to improve the solubility of the polymer.
Specific examples of the alkyl group include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, cyclohexyl, dodecyl, and the like.
The alkoxy group is not particularly limited, and is represented by an alkoxy group (-OR) 10 ) R of (2) 10 The alkyl group represented may have any of a linear, branched or cyclic structure, and in order to be able to improve the solubility of the polymer, the number of carbon atoms is preferably 1 or more, and more preferably 24 or lessMore preferably 12 or less.
Specific examples of the alkoxy group include: methoxy, ethoxy, n-propoxy, n-butoxy, hexyloxy, 1-methylpentyloxy, cyclohexyloxy and the like.
The aralkyl group is not particularly limited, but in order to be able to improve the solubility of the polymer, the number of carbon atoms is preferably 5 or more, more preferably 60 or less, and still more preferably 40 or less.
Specific examples of the aralkyl group include: 1, 1-dimethyl-1-phenylmethyl, 1-di (n-butyl) -1-phenylmethyl, 1-di (n-hexyl) -1-phenylmethyl, 1-di (n-octyl) -1-phenylmethyl, phenylethyl, 3-phenyl-1-propyl, 4-phenyl-1-n-butyl, 1-methyl-1-phenylethyl, 5-phenyl-1-n-propyl, 6-phenyl-1-n-hexyl, 6-naphthyl-1-n-hexyl, 7-phenyl-1-n-heptyl, 8-phenyl-1-n-octyl, 4-phenylcyclohexyl, and the like.
(l, m and n)
l represents 0 or 1, n represents 0 or 1.
l and n are each independently, and the value represented by l+n is preferably 1 or more, more preferably 1 or 2, and further preferably 2. The value represented by l+n, by being within the above range, tends to increase the solubility of the polymer contained in the first functional film and can suppress precipitation from the first composition containing the polymer.
m represents 1 or 2, and when the organic semiconductor element is an organic electroluminescent element, it is preferably 1 in view of the tendency to be driven at a low voltage and the improvement of hole injection energy, transport energy, and durability.
(p and q)
p represents 0 or 1, q represents 0 or 1. Note that, when p=1, l=1, and when q=1, n=1. When l=n=1, p and q are not 0 at the same time. When p and q are not 0 at the same time, the solubility of the polymer contained in the first functional film tends to be improved, and precipitation from the first composition containing the polymer can be suppressed. For the same reason as in the above cases a and b, it is preferable that the value represented by p+q is 1 or more, since the driving life of the organic semiconductor element is further prolonged.
(specific example of the main chain of the repeating unit represented by the formula (55))
The main chain structure excluding nitrogen atoms in the formula (55) is not particularly limited, and examples thereof include the following structures.
[ chemical 22]
[ chemical 23]
[ chemical 24]
[ chemical 25]
[ chemical 26]
[ chemical 27]
[ chemical 28]
[ chemical 29]
(repeating unit represented by the formula (56))
[ chemical 30]
(in the formula (56),
Ar 51 ar in the formula (50) 51 The same is true of the fact that,
Ar 41 and a divalent group formed by connecting one or more groups selected from the group consisting of a divalent aromatic hydrocarbon group which may have a substituent other than a crosslinking group and a divalent aromatic heterocyclic group which may have a substituent other than a crosslinking group, the connection being made directly or via a connecting group.
R 41 And R is 42 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like,
t is 1 or 2, and the number of the T is 1 or 2,
u is 0 or 1, and the number of the elements is,
r and s are each independently integers from 0 to 4. )
(R 41 、R 42 )
R in the repeating unit represented by the above formula (56) 41 、R 42 Each independently is an alkyl group which may have a substituent other than a crosslinking group or the like.
The alkyl group is a linear, branched or cyclic alkyl group. The number of carbon atoms of the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 or more, and further preferably 10 or less, more preferably 8 or less, and still more preferably 6 or less. The alkyl group is further preferably methyl or hexyl.
R in the repeating unit represented by the above formula (56) 41 And R is 42 Where there are plural, plural R' s 41 And R is 42 The same or different. R is R 41 There are a plurality of cases, examples of which include: r is 2 or more, t is 2 or more, or both. R is R 42 The presence of a plurality of s is a case where s is 2 or more.
(r, s, t and u)
In the repeating unit represented by formula (56), r and s are each independently an integer of 0 to 4. The value represented by r+s is preferably 1 or more, and further, r and s are each preferably 2 or less. When t is 1 or more, r is defined by t phenylene groups each independently, and s is defined when u=1.
If the value represented by r+s is 1 or more, it is considered that the driving life of the organic semiconductor element is further prolonged for the same reason as a and b in the above formula (54).
In the repeating unit represented by the above formula (56), t is 1 or 2,u is 0 or 1.t is preferably 1 and u is preferably 1.
(Ar 41 )
Ar 41 And a divalent group formed by connecting one or more groups selected from the group consisting of a divalent aromatic hydrocarbon group which may have a substituent other than a crosslinking group and a divalent aromatic heterocyclic group which may have a substituent other than a crosslinking group, the connection being made directly or via a connecting group.
As Ar 41 Examples of the aromatic hydrocarbon group and the aromatic hydrocarbon group in (B) include Ar in the above formula (50) 52 The same groups. The substituents which the aromatic hydrocarbon group and the aromatic hydrocarbon group may have are preferably the same as those of the substituent group Z, and further, the substituents which may have are also preferably the same as those of the substituent group Z.
(specific example of the repeating unit represented by the formula (56))
The repeating unit represented by the formula (56) is not particularly limited, and examples thereof include the following structures.
[ 31]
(repeating unit represented by the formula (57))
[ chemical 32]
(in the formula (57),
Ar 51 ar in the formula (50) 51 The same is true of the fact that,
R 17 ～R 19 each independently represents an alkyl group which may have a substituent other than a crosslinking group or the like, an alkoxy group which may have a substituent other than a crosslinking group or the like, an aralkyl group which may have a substituent other than a crosslinking group or the like, an aromatic hydrocarbon group which may have a substituent other than a crosslinking group or the like, or an aromatic heterocyclic group which may have a substituent other than a crosslinking group or the like,
f. g and h each independently represent an integer of 0 to 4, the value represented by f+g+h being 1 or more,
e represents an integer of 0 to 3. )
(R 17 ～R 19 )
R 17 ～R 19 Wherein each aromatic hydrocarbon group and aromatic heterocyclic group is independently the same as Ar 51 The same groups as the aromatic hydrocarbon groups and the aromatic heterocyclic groups listed in the formula (I). The substituent other than the crosslinking group and the like which may have these groups is preferably the same group as the substituent group Z described above.
R 17 ～R 19 The alkyl and aralkyl groups in (2) are preferably independently from the R 7 The same groups as those exemplified for the alkyl group and the aralkyl group, and further, substituents other than the crosslinking group and the like which may be present are also preferably the same as those for R 7 The same groups.
R 17 ～R 19 The alkoxy group in (a) is preferably an alkoxy group exemplified in the substituent group Z, and further, substituents other than a crosslinking group and the like which may be present are also the same as those in the substituent group Z.
(f、g、h)
f. g and h each independently represent an integer of 0 to 4, and the value represented by f+g+h is 1 or more. When e is 2 or more, g is defined by each of e phenylene groups independently.
The value represented by f+h is preferably 1 or more,
more preferably, the value represented by f+h is 1 or more, and f, g and h are each 2 or less,
further preferably, the value represented by f+h is 1 or more, and both f and h are 1 or less,
f. h is most preferably 1.
When f and h are both 1, R 17 And R is R 19 Preferably bonded at mutually symmetrical positions.
In addition, R is preferably 17 And R is R 19 Similarly, g is more preferably 2.
When g is 2, two R's are most preferred 18 Are bonded to each other in the para position, and when g is 2, two R's are most preferred 18 The same applies.
Here, R is 17 And R is R 19 Bonding to positions symmetrical to each other means bonding positions described below. However, in the notation, the same structure is considered as if the main chain is rotated 180 degrees about the axis.
[ 33]
The repeating unit represented by the above formula (57) is preferably a repeating unit represented by the following formula (58).
(repeating unit represented by the formula (58))
[ chemical 34]
In the case of the repeating unit represented by the above formula (58), g=0 or 2 is preferable. When g=2, the bonding positions are preferably No. 2 and No. 5. When g=0, i.e. there is no signal from R 18 When g=2 and the bonding positions are positions 2 and 5, i.e. the steric hindrance is located at two R 18 R is at the diagonal position of the bonded benzene ring 17 And R is R 19 Can be bonded at mutually symmetrical positions.
Further, the repeating unit represented by the above formula (58) is more preferably a repeating unit represented by the following formula (59) where e=3.
(repeating unit represented by the formula (59))
[ 35]
In the case of the repeating unit represented by the above formula (59), g=0 or 2 is preferable. When g=2, the bonding positions are preferably No. 2 and No. 5. When g=0, i.e. there is no signal from R 18 When g=2 and the bonding positions are positions 2 and 5, i.e. the steric hindrance is located at two R 18 R is at the diagonal position of the bonded benzene ring 17 And R is R 19 Can be bonded at mutually symmetrical positions.
(molecular weight of aromatic amine Polymer)
The molecular weight of the aromatic amine polymer contained in the first functional film is described below.
The aromatic amine polymer is preferably an aromatic amine polymer comprising a repeating unit represented by the above formula (50), and its weight average molecular weight (Mw) is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, further preferably 200,000 or less, particularly preferably 100,000 or less, and most preferably 50,000 or less. The weight average molecular weight is usually 2,500 or more, preferably 5,000 or more, more preferably 10,000 or more, further preferably 15,000 or more, and particularly preferably 17,000 or more.
When the weight average molecular weight of the aromatic amine polymer is not more than the upper limit, the solubility in a solvent tends to be excellent in film forming property. In addition, the weight average molecular weight of the aromatic amine polymer may be not less than the lower limit, so that the decrease in the glass transition temperature, melting point and vaporization temperature of the aromatic amine polymer may be suppressed, thereby improving heat resistance.
Conventionally, it has been considered that an industrially practical insolubility cannot be obtained with an aromatic amine polymer having no crosslinking group or the like having a weight average molecular weight of 15000 to 50000. By using the composition of the present invention, it is possible to realize the durability against the upper layer solvent for 2 minutes or more, preferably 15 minutes or more, which is industrially required, even by firing at a relatively low temperature for a short period of time.
The number average molecular weight (Mn) of the aromatic amine polymer is usually 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, particularly preferably 100,000 or less, and most preferably 40000 or less. The number average molecular weight is usually 2,000 or more, preferably 4,000 or more, more preferably 6,000 or more, and still more preferably 8,000 or more.
Further, the dispersity (Mw/Mn) of the aromatic amine polymer is preferably 3.5 or less, more preferably 2.5 or less, particularly preferably 2.0 or less. The smaller the value of the dispersity is, the better, so the lower limit value is desirably 1. If the dispersity of the aromatic amine polymer is less than the above upper limit, purification is easy and solubility to a solvent or charge transport ability is good.
Typically, the weight average molecular weight and number average molecular weight of the polymer are determined by SEC (size exclusion chromatography) measurements. In the SEC measurement, the elution time is shorter for the higher molecular weight component and longer for the lower molecular weight component, and the weight average molecular weight and number average molecular weight are calculated by converting the elution time of the sample into the molecular weight using a calibration curve calculated from the elution time of polystyrene (standard sample) having a known molecular weight.
(specific example)
Specific examples of the aromatic amine polymer are shown below, but the aromatic amine polymer in the present embodiment is not limited to these. The numbers in the chemical formulas represent the molar ratio of the repeating units. n represents the repetition number.
The aromatic amine polymer may be any of random copolymer, alternating copolymer, block copolymer, graft copolymer, and the like, and the order of the monomers is not limited.
[ 36]
/>
[ 37]
[ 38]
[ 39]
Specific examples of the aromatic amine polymer including the repeating unit represented by the formula (56) are shown below, but the aromatic amine polymer in the present embodiment is not limited to these. The numbers in the chemical formulas represent the molar ratio of the repeating units. n represents the repetition number.
The aromatic amine polymer may be any of random copolymer, alternating copolymer, block copolymer, graft copolymer, and the like, and the order of the monomers is not limited.
[ 40]
[ chemical 41]
(method for producing aromatic amine Polymer)
The method for producing the aromatic amine polymer contained in the first functional material is not particularly limited, and is arbitrary. Examples include: polymerization methods using a Suzuki reaction, polymerization methods using a Grignard reaction, polymerization methods using a Yamamoto reaction, polymerization methods using a Ullmann reaction, polymerization methods using a Buchwald-Hartwig reaction, and the like.
In the case of a polymerization method using Ullmann reaction and a polymerization method using Buchwald-Hartwig reaction, for example, a polymer comprising a repeating unit represented by the following formula (2), i.e., a repeating unit represented by the above formula (54), is synthesized by reacting a dihaloaryl group represented by the following formula (2 a) with a primary aminoaryl group represented by the following formula (2 b).
[ chemical 42]
(in the above reaction formula, Z represents a halogen atom such as I, br, cl, F. In addition, ar) 1 、R 1 、R 2 X, a to d and Ar in the above formula (54) 1 、R 1 、R 2 X, a to d have the same meaning. )
In addition, in the case of a polymerization method using Ullmann reaction and a polymerization method using Buchwald-Hartwig reaction, for example, a polymer comprising a repeating unit represented by the following formula (3), that is, a repeating unit represented by the above formula (55) is synthesized by reacting a dihaloaryl represented by the following formula (3 a) with a primary aminoaryl represented by the following formula (3 b).
[ chemical 43]
(in the above reaction formula, Z represents a halogen atom such as I, br, cl, F. In addition, ar) 2 、R 3 ～R 6 L to n, p, q and Ar in the above formula (55) 2 、R 3 ～R 6 L to n, p and q have the same meaning. )
In the above polymerization method, the reaction for forming an N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, sodium t-butoxide, or triethylamine. In addition, the reaction may be carried out in the presence of a transition metal catalyst such as copper or palladium complex.
(content of aromatic amine Polymer)
The content of the aromatic amine polymer in the first composition is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further usually 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 20% by mass or less. When the content of the aromatic amine polymer is within the above range, the first functional film to be formed is preferably not liable to cause defects and uneven film thickness.
(solvent)
The first composition typically contains a solvent. The solvent is preferably a solvent that dissolves the aromatic amine polymer. Specifically, a solvent that dissolves the aromatic amine polymer in the first composition at room temperature is generally suitable at 0.05 mass% or more, preferably 0.5 mass% or more, and more preferably 1 mass% or more.
Specific examples of the solvent include: aromatic solvents such as toluene, xylene, mesitylene, cyclohexylbenzene, and methylnaphthalene; halogen-containing solvents such as 1, 2-dichloroethane, chlorobenzene, o-dichlorobenzene, and the like; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); ether solvents such as aromatic ethers including 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethyl anisole, and 2, 4-dimethyl anisole; aliphatic ester solvents such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; organic solvents such as ester solvents including phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and aromatic esters such as n-butyl benzoate, and organic solvents used in a hole injection layer forming composition and a hole transport layer forming composition described below.
The solvent may be used alone, or two or more solvents may be used in any combination and in any ratio.
The surface tension of the solvent at 20℃is usually less than 40dyn/cm, preferably 36dyn/cm or less, more preferably 33dyn/cm or less. The lower limit of the surface tension is not particularly limited, but is usually 20dyn/cm or more.
On the other hand, the vapor pressure of the solvent at 25℃is usually 10mmHg or less, preferably 5mmHg or less, and usually 0.1mmHg or more. By using such a solvent, a first composition suitable for the properties of an aromatic amine polymer can be prepared, which is suitable for a process for producing an organic semiconductor element by a wet film forming method.
Specific examples of such solvents include: the above-mentioned aromatic solvents such as toluene, xylene, mesitylene, cyclohexylbenzene, ether solvents and ester solvents.
However, moisture may cause deterioration of the performance of the organic semiconductor element, and among them, particularly, it may promote a decrease in luminance at the time of continuous driving as the organic electroluminescent element. Therefore, in order to reduce the water remaining in the wet film formation as much as possible, the solubility of the solvent in water at 25 ℃ is preferably 1 mass% or less, more preferably 0.1 mass% or less, and the smaller is more preferable.
The content of the solvent in the first composition is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 80% by mass or more. The content of the solvent is not less than the lower limit, so that the flatness and uniformity of the formed layer can be improved. The upper limit of the content of the solvent is not particularly limited, but is usually 99.95 mass% or less.
< second composition >
The second composition is a composition that is coated on the first functional film to form a second functional film. The second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃. The solvent contains at least one first solvent component having a viscosity of 3 mPas or more at 23 ℃ or at least one first solvent component having a flow activation energy of 17kJ/mol or more and at least one second solvent component having a viscosity of less than 3 mPas at 23 ℃.
In addition, the second composition may contain a second functional material different from the first functional material contained in the first composition. For example, when the organic semiconductor element is an organic electroluminescent element and the second functional film is a light-emitting layer, a functional material such as a light-emitting material is usually used as the second functional material.
In one embodiment of the present invention, the viscosity of the first solvent component at 23 ℃ is 3mpa·s or more, whereby the first functional film is not dissolved. The viscosity is preferably 4 mPas or more, more preferably 5 mPas or more. In addition, from the viewpoint of film flatness in the pixel, the first solvent viscosity is desirably 20mpa·s or less. In this embodiment, the solvent may contain only the first solvent component or may contain other solvent components.
The upper limit of the viscosity of the second composition varies depending on the coating method. When applied by an inkjet device, the viscosity of the second composition at 23 ℃ is preferably 15mpa·s or less, more preferably 12mpa·s or less, and even more preferably 10mpa·s or less, from the viewpoint of ease of ejection from the inkjet head. Further, from the viewpoint of ejection stability, the viscosity of the second composition at 23 ℃ is preferably 1mpa·s or more, and more preferably 2mpa·s or more.
The viscosity in the present embodiment is a value measured using an E-type viscometer RE85L (manufactured by eastern machine industry) at 23℃using a cone rotation speed of 20rpm to 100 rpm.
When the second composition is applied over a large area, the dipping time is long. During this time, the temperature of the second composition decreases and the viscosity increases by the continued evaporation of the solvent. If a solvent having a high temperature dependence (flow activation energy) of viscosity is used as the first solvent component, the first solvent composition ratio in the second composition can be reduced by using a solvent having a lower initial viscosity as the first solvent component. Thus, by reducing the initial viscosity of the solvent, a more suitable composition can be obtained when ejection is performed by the inkjet method.
From this viewpoint, as another embodiment of the present invention, a first solvent component having a flow activation energy of 17kJ/mol or more and a second solvent component having a viscosity of less than 3 mPas are contained. The flow activation energy of the first solvent component is 17kJ/mol or more, more preferably 19kJ/mol or more, and still more preferably 21kJ/mol or more. The upper limit is not particularly limited, but is preferably 40kJ/mol or less, more preferably 35kJ/mol or less, still more preferably 32kJ/mol or less, and particularly preferably 30kJ/mol or less. The higher the flow activation energy, the greater the viscosity increase due to the temperature decrease when latent heat is carried away by volatilization of the solvent, and thus is preferable.
As another aspect of the present invention, the solvent contains a first solvent component having a viscosity of 3mpa·s or more at 23 ℃ and a flow activation energy of 17kJ/mol or more, and further contains a second solvent component having a viscosity of less than 3mpa·s at 23 ℃. Preferred ranges for the viscosity and flow activation energy of the first solvent component at 23 ℃ are as described above.
< specific examples of the first solvent component >
As the first solvent component contained in the solvent contained in the second composition, for example, a compound having a viscosity of 3mpa·s or more at 23 ℃ among the above-mentioned compounds in the solvent contained in the first composition may be used, and examples thereof include: isoamyl benzoate (3.36), 2-isopropylnaphthalene (3.45), fenchyl ketone (3.47), decylbenzene (3.5), hexyl benzoate (4.08), 3-ethylbiphenyl (5.01), 2-ethylhexyl benzoate (5.9), 2-phenoxyethyl isobutyrate (6.28), 4-isopropylbiphenyl (6.61), ethyl 4-methoxybenzoate (6.77), alpha-tetrahydronaphthalenone (7.2), t-butylphenyl carbonate (7.24), 1-naphthaldehyde (7.24), 2-phenoxyethyl acetate (7.56), benzyl benzoate (8.45), diethyl phthalate (10.58), 1-diphenylpentane (10.8), benzyl phenyl carbonate (16.2). The numbers in parentheses attached to the solvent below represent the viscosity (unit: mPa.s) at 23 ℃.
As the first solvent component contained in the solvent contained in the second composition, for example, a compound having a flow activation energy of 17kJ/mol or more among the above-mentioned compounds in the solvent contained in the first composition may be used, and examples thereof include: isoamyl benzoate (17.9), fenchyl ketone (17.8), hexyl benzoate (19.5), 2-ethylhexyl benzoate (23.4), 4-isopropylbiphenyl (24.6), benzyl benzoate (24.5), 1-diphenylpentane (29.7), benzyl phenyl carbonate (32.6). The numerals in parentheses attached to the solvent indicate the flow activation energy (unit: kJ/mol).
The flow activation energy is E in the following formula (I). The viscosity of the solvent was measured by changing the temperature, and the flow activation energy was obtained from the slope of the viscosity by taking the point of the logarithm of the viscosity to the reciprocal of the temperature.
Can be obtained from η=aexp (E/RT) (I).
η: viscosity (cP)
A: constant (constant)
E: flow activation energy (kJ/mol)
R: gas constant (8.314J/K/mol)
T: temperature (K)
The second composition can realize industrially desired insolubilization durability of 2 minutes or more, preferably 5 minutes or more, more preferably 15 minutes or more even in a film containing a first functional material having a small molecular weight fired at a relatively low temperature/in a short time, by containing one or more first solvent components satisfying a viscosity of 3mpa·s or more at 23 ℃ and/or a flow activation energy of 17kJ/mol or more, and the aromatic amine polymer of the first functional film is not insolubilized by a crosslinking group or the like. This is thought to be because the heat treatment rearranges the surface or interface of the first functional film before the bulk to form a relatively insoluble coating, thereby inhibiting the penetration or elution of the solvent into the first functional film. The ease of penetration into the interior varies depending on the volume or shape of the solvent molecules contained in the second composition and the degree of freedom in the interior. In addition, the greater the intermolecular force between solvent molecules, the more the barrier to osmotic dispersion becomes. The above-mentioned plurality of elements are more accurately determined by the following relational expression (a), but are simply realized by using one or more first solvent components having a viscosity of 3mpa·s or more at 23 ℃.
From the viewpoint of ensuring the solubility of the second functional material, the first solvent component is preferably a solvent having an aromatic hydrocarbon structure, and specifically, may be given as follows: a solvent component having a structure such as benzoic acid, biphenyl, naphthalene, etc.
The hansen solubility parameter δp of the first solvent component preferably satisfies δp <10, and even more preferably satisfies δp <7. Although the durability time tends to be shortened by the solvent of high polarity due to the insolubilization property of the first functional film, δp in this range can ensure a more sufficient insolubilization durability time.
In addition, the theoretical surface area of the first solvent component calculated from the COSMO-RS solvation model is preferablyVolume->And a boiling point (. Degree.C.) and a viscosity at 23℃of mPas satisfy the following relational expression (A). The first solvent component can be insoluble for a longer period of time by satisfying the following relational expression (a).
32X viscosity-4.3X theoretical surface area +5.4X volume-boiling point >150 … (A)
In the above-mentioned relational expression (A), the "viscosity" is the viscosity (mPas) of the first solvent component at 23 ℃. "boiling point" is the boiling point of the first solvent component at atmospheric pressure. The "theoretical surface area" and "volume" of the first solvent component are determined by A.Klamt, COSMO-RS: values calculated by the method described in quantum chemistry to fluid phase thermodynamics and drug design (From Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design), elsevier Science, first edition (9/29/2005). Briefly, the volume obtained by superimposing a VDW sphere on the atom of a structurally optimized molecule and the surface area thereof (the cavity volume used in the COSMO method calculation) are integrated.
Each coefficient in the above-mentioned relational expression (a) is an experimentally obtained value.
The viscosity shows the integrated forces between the solvent molecules and is related to the ease of penetration/dispersion into the first functional film. Further, the larger the volume of the solvent molecule, the less likely it is to permeate the first functional film, but the larger the surface area, the farther away from the spherical shape, the smaller the cross-sectional area, i.e., the shape having a direction of easy permeation, with respect to the same volume, and therefore, the smaller the surface area is preferred. The lower boiling point solvent is more easily evaporated, and the temperature of the second composition is lowered by the vaporization heat, and as a result, the effect of increasing the viscosity of the solvent is exhibited. In addition, the concentration of the solid material in the second composition is increased by vaporization of the solvent, and the action of the solvent on the base functional material film is suppressed.
From the standpoint of insolubilization, the value represented by the left side of the above-mentioned relational expression (a) is more preferably 160 or more, and still more preferably 180 or more. The first solvent component satisfying the above-mentioned relation (a) includes, for example: isoamyl benzoate (3.45), fenchyl ketone (3.47), decylbenzene (3.5), hexyl benzoate (4.08), 2-ethylhexyl benzoate (5.9), 2-phenoxyethyl isobutyrate (6.28), 4-isopropylbiphenyl (6.61), ethyl 4-methoxybenzoate (6.77), t-butylphenyl carbonate (7.24), 1-naphthaldehyde (7.24), 2-phenoxyethyl acetate (7.56), benzyl benzoate (8.45), 1-diphenylpentane (10.8), and benzyl phenyl carbonate (16.2). The numbers in parentheses attached to the solvent below represent the viscosity at 23 ℃.
< other solvent component/composition >
The second composition may contain a solvent other than the first solvent component. The solvent other than the first solvent component may have a second solvent component having a lower viscosity than the first solvent component. That is, the second solvent component is a solvent having a viscosity of less than 3 mPas at 23 ℃. Specifically, there may be mentioned: among the solvents exemplified as the solvents contained in the first composition, the solvents having a viscosity of less than 3mpa·s at 23 ℃. The second solvent component is preferably contained in a case where the flow activation energy of the first solvent component satisfies 17kJ/mol or more.
The flow activation energy of the second solvent component is preferably 10kJ/mol or more, more preferably 12kJ/mol or more, and still more preferably 14kJ/mol or more. The upper limit is not particularly limited, but is preferably 18kJ/mol or less, more preferably 17kJ/mol or less, still more preferably 16kJ/mol or less, and particularly preferably 15kJ/mol or less.
In the case of application by an inkjet device, it is desirable to contain a low-viscosity second solvent component to reduce the viscosity of the entire second composition from the viewpoint of being properly ejected from an inkjet head. Among them, the boiling point of the second solvent component is preferably 180 ℃ or higher from the viewpoint of avoiding drying in the step of applying the second composition to provide the second functional film.
Examples of such a second solvent component include: ethyl benzoate, tetrahydronaphthalene, 2-ethyl naphthalene, ethyl toluate, cyclohexylbenzene, butyl benzoate.
From the viewpoint of securing the insolubilization time, the total content of the first solvent component in the second composition is preferably 15% by mass or more, more preferably 20% by mass or more, and still more preferably 25% by mass or more. The upper limit of the total content of the first solvent components is not particularly limited, but is usually 99 mass% or less. In view of the normal solid content, the total content of the first solvent components is preferably 95 mass% or less, and when the second solvent components are contained, the total content of the first solvent components is preferably 90 mass% or less. Further, from the viewpoint of the solvent evaporation property, the total content of the first solvent components is preferably 70 mass% or less, more preferably 50 mass% or less.
When the solvent of the second composition is a mixed solvent containing a second solvent component in addition to the first solvent component, the ratio of the first solvent component to the total of the first solvent component and the second solvent component is preferably 10% or more, more preferably 15% or more by mass. This is because, considering the evaporation sequence of the mixed solvent, it is desirable that a certain amount of the first solvent component remains until the second solvent component, which is not equivalent to the first solvent component, evaporates.
The proportion of the second solvent component to the total of the first solvent component and the second solvent component is preferably 30 mass% or more. By the evaporation of the second solvent component, the temperature of the first solvent can be appropriately reduced by 30 mass% or more, and the viscosity of the first solvent component can be increased. The proportion of the second solvent component is more preferably 50% by mass or more, and most preferably 70% by mass or more.
The proportion of the second solvent component is preferably 90 mass% or less from the viewpoint of flatness of the functional film, and more preferably 85 mass% or less from the viewpoint of a certain amount of the first solvent component remaining until the second solvent component evaporates.
In addition, from the viewpoint of evaporating the second solvent component earlier than the first solvent component, the boiling point of the second solvent component is preferably lower than that of the first solvent component, preferably 280 ℃ or lower, and more preferably 250 ℃ or lower. On the other hand, from the viewpoint of drying control at the time of large-area coating, the boiling point of the second solvent component is preferably 180 ℃ or higher, more preferably 200 ℃ or higher.
As described above, from the viewpoint of not dissolving the first functional layer as the lower layer, the second composition preferably has a first solvent component having a viscosity of 3mpa·s or more at 23 ℃. On the other hand, from the viewpoint of the ejection property of the inkjet coating, the viscosity of the composition is preferably low (the viscosity at 23 ℃ C. Is 15 mPas or less). From the viewpoint of reduction in the overall viscosity of the second composition, the second composition preferably has a second solvent component having a viscosity of less than 3mpa·s at 23 ℃.
The second solvent component is preferably contained in a case where the flow activation energy of the first solvent component satisfies 17kJ/mol or more. The flow activation energy of the first solvent component is 17kJ/mol or more, which facilitates both the inkjet ejectability and the insolubility of the lower layer. The second solvent component is a low viscosity solvent (viscosity less than 3 mPa-s at 23 ℃) and tends to volatilize earlier than the first solvent component. At this time, the vaporization heat is taken away, and the temperature of the second composition is lowered. The second composition remaining in the first composition has a high viscosity due to a high flow activation energy of the first solvent component, and therefore is preferably not dissolved because it is less likely to penetrate into the first functional layer as the lower layer.
The second composition may contain a second functional material that is different from the first functional material.
When the organic semiconductor element is an organic electroluminescent element and the second functional film is a hole transport layer, examples of the second functional material include hole transport materials. As the hole transport material, for example, the same polymer as the aromatic amine polymer of the formula (50) of the first functional film may be contained, and a hole transport material described later may be used.
When the organic semiconductor element is an organic electroluminescent element and the second functional film is a light-emitting layer, a light-emitting material such as a phosphorescent light-emitting material or a charge transport material, which will be described later, may be used as the second functional material. In addition, the second functional material preferably contains a low-molecular aromatic compound. When the second functional material is a low molecule, the viscosity of the second composition can be reduced as compared with a high molecule. When a high-viscosity solvent is used as the first solvent component or when the first solvent component is used in a high composition ratio, the viscosity of the entire second composition tends to be increased, but the second functional material is easily acceptable when it is a low-molecular material.
As the low-molecular aromatic compound, for example, a charge transport material used for the light-emitting layer, a material described later can be used. The molecular weight of the low-molecular aromatic compound is preferably less than 5000, more preferably 4000 or less, further preferably 3000 or less, particularly preferably less than 2000.
The second composition of the present embodiment may contain only one type of second functional material, or may contain two or more types of second functional materials.
(content of solvent and functional Material)
The content of the first functional material and the second functional material in the first composition and the second composition in the present embodiment is not particularly limited, but is preferably 0.1 wt% or more, more preferably 0.5 wt% or more, more preferably 1.0 wt% or more, preferably 20 wt% or less, more preferably 15 wt% or less, more preferably 10 wt% or less, respectively.
< film Forming by Wet film Forming method >
The method for manufacturing an organic semiconductor element according to the present embodiment includes: a step of applying a first composition and heating to provide a first functional film; and a step of applying a second composition to the first functional film to provide a second functional film.
As these steps, when the organic semiconductor element is an organic electroluminescent element, examples include: examples i) and ii) below in which the first functional film is a hole injection layer and the second functional film is a hole transport layer, or in which the first functional film is a hole transport layer and the second functional film is a light-emitting layer, are not limited thereto.
i) A step of applying a first composition to the anode and heating the composition to provide a hole injection layer as a first functional film; and a step of applying a second composition to the hole injection layer to provide a hole transport layer as a second functional film.
ii) a step of applying a first composition onto the hole injection layer and heating the applied first composition to provide a hole transport layer as a first functional film; and a step of applying a second composition to the hole transport layer to provide a light-emitting layer as a second functional film.
When the organic semiconductor element in this embodiment mode is an organic electroluminescent element, a substrate provided with an electrode generally has a minute region in which a light-emitting pixel is divided by a partition wall called a bank. The first functional film is formed by spraying the first composition or the like in the present embodiment in the minute region partitioned by the bank, and then applying and drying the composition and heating the composition appropriately.
The ejection method is a method of ejecting droplets smaller than the minute areas divided by the banks from minute nozzles, and it is preferable to fill the minute areas divided by the banks with the first composition by ejecting a plurality of droplets. As the ejection method, an inkjet method is preferable.
In the wet film forming method, the minute regions divided by the banks are filled with the first composition, and then vacuum drying is performed. Vacuum drying refers to volatilizing the solvent by decompression.
Most of the solvent can be volatilized by vacuum drying, but for sufficient drying, it is preferable to subsequently carry out heat drying. The heating temperature is preferably set to a temperature and a time at which the first functional film does not crystallize or agglomerate.
When the first composition contains a functional material as a low-molecular material, the heating temperature is usually 50 ℃ or higher, preferably 80 ℃ or higher, more preferably 100 ℃ or higher, more preferably 120 ℃ or higher, usually 200 ℃ or lower, preferably 180 ℃ or lower, more preferably 150 ℃ or lower. The heating time is usually 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more, and usually 120 minutes or less, preferably 90 minutes or less, more preferably 60 minutes or less.
Since the first functional material contains an aromatic amine polymer as a high molecular material, the heating temperature is usually 80 ℃ or higher, preferably 100 ℃ or higher, more preferably 150 ℃ or higher, more preferably 200 ℃ or higher, usually 300 ℃ or lower, preferably 270 ℃ or lower, more preferably 240 ℃ or lower. The heating time is usually 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more, and usually 120 minutes or less, preferably 90 minutes or less, more preferably 60 minutes or less.
The heating temperature in the step of providing the first functional film is preferably lower within a range in which the solvent is removed and the required insolubilization durability time is achieved, and the heating may be performed at a temperature lower than the glass transition temperature of the aromatic amine polymer.
The heating method may be performed by a hot plate, an oven, infrared irradiation, or the like. In the case of infrared irradiation in which molecular vibration is directly applied, it is sufficient that the heating time is close to the lower limit, and in the case of hot plate heating in which the substrate is directly contacted with the heat source or the heat source and the substrate are disposed very close to each other, it takes longer time than the infrared irradiation. In the case of heating in an oven, that is, in the case of heating with an inert gas such as air, nitrogen, or argon in general, the temperature rise takes time, and therefore a heating time close to the upper limit of the heating time is preferable. The heating time is appropriately adjusted according to the heating method.
The second composition is coated on the first functional film formed in the bank by coating and heating to form a second functional film. The method of coating is the same as the first composition, preferably an inkjet method.
In this embodiment, the second composition to be applied contains at least one first solvent component satisfying a viscosity of 3mpa·s or more at 23 ℃ and/or a flow activation energy of 17kJ/mol or more, and therefore the first functional film is not dissolved for a time of industrial necessity or longer. In the industry, a process of forming a film on a large substrate by an inkjet method, in particular, a process of applying a second composition onto a first functional film requires at least 2 minutes, i.e., at least 2 minutes, from the time of applying the second composition onto the first functional film until the solvent contained in the second composition evaporates. Here, impregnation means that the second composition exists in a state of being in contact with the entire surface or part of the first functional film in a liquid state.
Therefore, the first functional film is preferably insoluble in the impregnation for preferably 2 minutes or more, more preferably 5 minutes or more, still more preferably 10 minutes or more, still more preferably 15 minutes or more. The air pressure and the temperature at this time are assumed to be 1Pa to 50℃respectively.
The term "solvent evaporation" as used herein means that the solvent contained in the second composition is evaporated and removed as a whole. That is, the case where the solvent contained in the second composition is only the first solvent component means that the first solvent component evaporates and disappears, and the case where the solvent contained in the second composition is the first solvent component and the second solvent component means that all of the solvents evaporate and disappear.
In addition, the solvent evaporation need not be so strict that the amount of residual solvent is 0. Since the residual solvent may remain depending on the boiling point of the solvent, if the concentration of the second functional film on the volume basis is 100ppm or less, evaporation may be regarded as disappearing.
The first functional film need not be insoluble at all positions in the cross-sectional direction. Even in the case of a polymer material which does not generate a chemical bond formed by a crosslinking group or the like, if an aromatic amine polymer having an appropriate molecular structure/molecular weight is heat-treated, the surface or interface is rearranged before the bulk portion, and a surface which is not easily eluted by a solvent at the time of coating with an upper layer is formed. At this time, most of the film remains in an amorphous state, and the surface dissolves rapidly after dissolution.
In a range where the insolubility can be achieved, the first functional film can use a low molecular weight functional material that is advantageous in terms of simpler heat treatment at low temperature for a short time, high definition, and freedom in film thickness design.
In the above-described insoluble state, the influence of the second composition on the endurance time until the first functional film starts to dissolve varies depending on the solvent molecules contained in the second composition, in particular, the volume/surface area/internal degree of freedom/intermolecular force between solvent molecules of the first solvent component, and the like. Although substantially uncorrelated with the hansen solubility parameter δp of the solvent molecules, solvent molecules with δp that are above a certain large tend to shorten the endurance time, suggesting avoidance.
The inventor sets forth a selection standard of preferable solvent molecules through experiments, and establishes a judgment formula. This is the following relation (A) described above.
32X viscosity-4.3X theoretical surface area +5.4X volume-boiling point >150 … (A)
In addition, this determination can be made simply based on the viscosity of the solvent.
In addition, when the second composition is applied to the first functional film, it is assumed that an inkjet device is used, and a viscosity suitable for ejection as a whole of the second composition, that is, a viscosity of 15mpa·s or less is necessary. However, according to the coating method, it is not necessary to set the thickness to 15 mPas or less.
[ first functional film and second functional film ]
The content of the first functional material or the second functional material contained in the first functional film or the second functional film is usually 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, particularly preferably 95% by weight or more, most preferably substantially 100% by weight, and the upper limit is 100% by weight. Substantially 100 wt% means that the functional film may contain trace amounts of additives, residual solvents, and impurities. The content of the functional material in the functional film is within this range, so that the function of the functional material can be more effectively exhibited.
[ method for Forming layers of organic electroluminescent device ]
A preferred example of an embodiment of a layer structure and a method of forming the same when the organic semiconductor element manufactured using the first composition and the second composition in the present embodiment is an organic electroluminescent element (hereinafter, sometimes referred to as an "organic electroluminescent element in the present embodiment") will be described with reference to fig. 1.
Fig. 1 is a schematic cross-sectional view showing an example of the structure of an organic electroluminescent element 10 according to the present embodiment. In fig. 1, 1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light emitting layer, 6 denotes a hole blocking layer, 7 denotes an electron transport layer, 8 denotes an electron injection layer, and 9 denotes a cathode.
The organic electroluminescent element in the present embodiment has the anode 2, the light-emitting layer 5, and the cathode 9 as essential constituent layers, but may have other functional layers between the anode 2 and the light-emitting layer 5 and between the cathode 9 and the light-emitting layer 5 as required, as shown in fig. 1.
[ substrate ]
The substrate 1 is a support for an organic electroluminescent element.
As the substrate 1, a plate of quartz or glass, a metal plate or foil, a plastic film or sheet, or the like is used. Particularly preferred are glass plates; transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, polysulfone, and the like.
When a synthetic resin substrate is used, the gas barrier property is preferably taken into consideration. The substrate is preferably large because the gas barrier property of the substrate is less likely to deteriorate due to external air passing through the substrate. Therefore, a method of providing a dense silicon oxide film or the like on at least one surface of a synthetic resin substrate to secure gas barrier properties is also one of preferred methods.
[ Anode ]
The anode 2 is an electrode that functions to inject holes into a layer on the light-emitting layer 5 side.
The anode 2 is generally composed of a metal such as aluminum, gold, silver, nickel, palladium, platinum, or the like, a metal oxide such as indium and/or tin oxide, a metal halide such as copper iodide, carbon black, or a conductive polymer such as poly (3-methylthiophene), polypyrrole, polyaniline, or the like.
The anode 2 is usually formed by a sputtering method, a vacuum deposition method, or the like.
When the anode 2 is formed using fine metal particles such as silver, fine particles such as copper iodide, fine particles of carbon black, fine particles of conductive metal oxide, fine conductive polymer powder, or the like, the anode 2 may be formed by dispersing these fine particles or the like in a suitable binder resin solution and applying the solution to the substrate 1.
In the case of a conductive polymer, a thin film may be directly formed on the substrate 1 by electrolytic polymerization.
Further, the anode 2 may be formed by coating a conductive polymer on the substrate 1 (applied physical express (appl. Phys. Lett.)), volume 60, page 2711, 1992).
The anode 2 is generally of a single-layer structure, but may be made of a laminated structure composed of a plurality of materials as desired.
The thickness of the anode 2 may be appropriately selected according to the desired transparency and the like.
When transparency is required, the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 2 is usually 5nm or more, preferably 10nm or more, usually 1000nm or less, preferably about 500nm or less.
The thickness of the anode 2 may be arbitrary in the case of being opaque.
A substrate 1 having the function of the anode 2 can be used. Different conductive materials may be stacked on the anode 2.
In order to remove impurities adhering to the anode 2 and to adjust the ionization potential to improve hole injection, it is also preferable to perform Ultraviolet (UV)/ozone treatment or oxygen plasma or argon plasma treatment on the surface of the anode 2.
[ hole injection layer ]
The hole injection layer 3 is a layer into which holes flow from the electrode when holes are transported from the anode 2 to the light-emitting layer 5. When the hole injection layer 3 is provided, the hole injection layer 3 is generally formed on the anode 2.
The method for forming the hole injection layer 3 may be a vacuum vapor deposition method or a wet film formation method, and is not particularly limited. From the viewpoint of reducing dark spots, the hole injection layer 3 is preferably formed by a wet film formation method.
The film thickness of the hole injection layer 3 is usually 5nm or more, preferably 10nm or more, usually 1000nm or less, preferably 500nm or less.
(hole transporting Material)
The composition for forming a hole injection layer generally contains a hole transport material and a solvent as constituent materials of the hole injection layer 3.
The hole transport material may be a polymer compound such as a polymer or a low molecular compound such as a monomer, and is preferably a polymer compound, as long as it is a compound having hole transport property that is usually used for the hole injection layer 3 of the organic electroluminescent element.
The hole transport material is preferably a compound having an ionization potential of 4.5eV to 6.0eV from the viewpoint of a charge injection barrier from the anode 2 to the hole injection layer 3. Examples of the hole transport material include: aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzyl phenyl derivatives, compounds having a tertiary amine linked with a fluorenyl group, hydrazone derivatives, silazane derivatives, silanol derivatives, phosphamide derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythiophene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon, and the like.
In the present specification, for example, an aromatic amine derivative is exemplified, and the derivative includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton, and may be a polymer or a monomer.
The hole transport material used as the material of the hole injection layer 3 may contain any one of these compounds alone or two or more kinds thereof. When two or more hole transporting materials are contained, the combination is arbitrary, but it is preferable to use one or more of the aromatic tertiary amine polymer compounds in combination with one or more of the other hole transporting materials.
Among the above examples, the hole transport material is preferably an aromatic amine compound, and particularly preferably an aromatic tertiary amine compound, from the viewpoints of amorphism and visible light transmittance. The aromatic tertiary amine compound means a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.
The type of the aromatic tertiary amine compound is not particularly limited, but a polymer compound (a polymer compound in which repeating units are linked) having a weight average molecular weight of 1000 or more and 1000000 or less is more preferable from the viewpoint of uniform light emission due to the surface smoothing effect. Preferable examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (1) or (11).
[ 44]
(in the formula (1),
Ar 3 represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, ar 4 Represents a divalent group formed by linking one group or a plurality of groups selected from at least one of a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group which may have a substituent, and the linking is performed directly or via a linking group. )
In the above formula (1), the linking group in the case where the aromatic hydrocarbon group and the aromatic heterocyclic group are linked via a plurality of linking groups is a divalent linking group, and examples thereof include: 1 to 30, preferably 1 to 5, further preferably 1 to 3 selected from-O-groups, -C (=O) -groups and (optionally substituted) -CH are linked in any order 2 -a group of groups.
Among the linking groups, ar in the formula (1) is preferable in view of excellent hole injection into the light-emitting layer 4 An aromatic hydrocarbon group or an aromatic heterocyclic group which is formed by a plurality of linking groups represented by the following formula (2).
[ 45]
(in the formula (2),
d represents an integer of 1 to 10,
R 8 and R is 9 Each independently represents a hydrogen atom or an alkyl group which may have a substituent, an aromatic hydrocarbon group or an aromatic heterocyclic group.
At R 8 、R 9 Where there are plural, they may be the same or different. )
[ chemical 46]
(in the above formula (11), j, k, l ', m', n ', p' each independently represent an integer of 0 or more, but l '+m'. Gtoreq.1. Ar) 11 、Ar 12 、Ar 14 Each independently represents a divalent aromatic ring group having 30 or less carbon atoms which may have a substituent. Ar (Ar) 13 Represents a divalent aromatic ring group having 30 or less carbon atoms which may have a substituent or a divalent group represented by the following formula (12), Q 11 、Q 12 Each independently represents an oxygen atom, a sulfur atom, or a hydrocarbon chain having 6 or less carbon atoms which may have a substituent, S 1 ～S 4 Each independently represented by a group represented by the following formula (13).
The aromatic ring group as used herein means at least one of an aromatic hydrocarbon ring group and an aromatic heterocyclic group. )
As Ar 11 、Ar 12 、Ar 14 Examples of the aromatic ring group of (a) include: monocyclic, two-to six-membered condensed rings or groups formed by connecting more than 2 of these aromatic rings.
Specific examples of the aromatic ring group having a single ring or a two-to six-membered condensed ring include the following divalent groups: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring,A ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring, a biphenyl, a terphenyl, a tetrabiphenyl, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a pyridine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. Wherein the negative charge is effectively made to be non-localIn terms of the domain formation, stability, and heat resistance, a divalent group or a biphenyl group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring is preferable.
As Ar 13 And Ar 11 、Ar 12 、Ar 14 The same applies.
[ 47]
(in the above formula (12), R 11 Represents an alkyl group, an aromatic ring group, or a trivalent group composed of an alkyl group having 40 or less carbon atoms and an aromatic ring group, and these may have a substituent. R is R 12 An alkyl group, an aromatic ring group, or a divalent group composed of an alkyl group having 40 or less carbon atoms and an aromatic ring group, and these may have a substituent. Ar (Ar) 31 Represents a monovalent aromatic ring group or a monovalent crosslinking group, which may have a substituent. q' represents an integer of 1 to 4. When q' is 2 or more, a plurality of R 12 The same or different, a plurality of Ar 31 The same or different. Asterisks indicate the bonding site to the nitrogen atom of formula (11). )
As R 11 The aromatic ring group of (a) is preferably 1 or 2 to 6 groups of a monocyclic or condensed ring having 3 or more and 30 or less carbon atoms, and specific examples thereof include trivalent groups derived from: benzene ring, fluorene ring, naphthalene ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring and groups formed by connecting 2 to 6 of the above groups.
As R 11 The alkyl group of (a) is preferably a straight chain, branched or cyclic alkyl group having 1 to 12 carbon atoms, and specific examples thereof include: radicals from methane, ethane, propane, isopropyl, butane, isobutane, pentane, hexane, octane, and the like.
As R 11 The group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group is preferably: straight-chain, branched or cyclic alkyl groups having 1 to 12 carbon atoms and mono-or mono-cyclic alkyl groups having 3 to 30 carbon atomsAnd a group formed by connecting 1 or 2 to 6 groups of the aromatic ring groups of the ring or condensed ring.
As R 12 Specific examples of the aromatic ring group of (a) include divalent groups derived from: benzene ring, fluorene ring, naphthalene ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, and a linking ring having 30 or less carbon atoms, which is obtained by linking these rings.
As R 12 Specific examples of the alkyl group of (a) include the following divalent groups: methane, ethane, propane, isopropyl, butane, isobutane, pentane, hexane, octane.
As Ar 31 Specific examples of the aromatic ring group of (a) include monovalent groups derived from: benzene ring, fluorene ring, naphthalene ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, and a linking ring having 30 or less carbon atoms, which is obtained by linking these rings.
As examples of preferred structures of formula (12), the following structures are given as R 11 The benzene ring or fluorene ring of the main chain in the following structure of the partial structure of (a) may further have a substituent.
[ 48]
As Ar 31 Examples of the crosslinking group of (a) include: groups from benzocyclobutene rings, naphthocyclobutene rings or oxetane rings, vinyl groups, acrylic groups, and the like. From the viewpoint of stability of the compound, a group derived from a benzocyclobutene ring or a naphthocyclobutene ring is preferable.
[ 49]
(in the formula (13), x and y each independently represent an integer of 0 or more, ar 21 、Ar 23 Each independently represents a divalent aromatic ring group, and these groups may have a substituent. Ar (Ar) 22 Represents a monovalent group which may have a substituentAromatic ring radical, R 13 Represents an alkyl group, an aromatic ring group or a divalent group composed of an alkyl group and an aromatic ring group, which may have a substituent. Ar (Ar) 32 Represents a monovalent aromatic ring group or a monovalent crosslinking group, which may have a substituent. Asterisks indicate the bonding site to the nitrogen atom of formula (11). )
As Ar 21 、Ar 23 And Ar 11 、Ar 12 、Ar 14 The same is true of (a).
As Ar 22 、Ar 32 Examples of the aromatic ring group of (a) include: monocyclic, two-to six-membered condensed rings, or groups formed by connecting two or more of these aromatic rings. Specific examples thereof include monovalent groups derived from: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, A ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring, a biphenyl, a terphenyl, a tetrabiphenyl, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a pyridine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. Among them, monovalent groups or biphenyl groups derived from benzene rings, naphthalene rings, fluorene rings, pyridine rings or carbazole rings are preferable from the viewpoint of efficiently non-localizing negative charges and excellent stability and heat resistance.
As R 13 Examples of alkyl or aromatic ring groups of (C) and R 12 The same applies.
Ar 32 The crosslinking group of (2) is not particularly limited, and preferable examples thereof include: from benzocyclobutene rings, naphthocyclobutenesA group of a ring or oxetane ring, vinyl group, acrylic group, etc.
Ar as described above is not departing from the gist of the present invention 11 ～Ar 14 、R 11 ～R 13 、Ar 21 ～Ar 23 、Ar 31 ～Ar 32 、Q 11 、Q 12 May have a substituent. The molecular weight of the substituent is preferably 400 or less, and more preferably 250 or less. The kind of the substituent is not particularly limited, and examples thereof include one or two or more kinds selected from the substituent group W described below.
[ substituent group W ]
Alkyl groups having 1 or more carbon atoms, preferably 10 or less carbon atoms, more preferably 8 or less carbon atoms, such as methyl group and ethyl group; alkenyl groups having 2 or more carbon atoms, preferably 11 or less carbon atoms, more preferably 5 or less carbon atoms, such as vinyl groups; alkynyl groups having 2 or more carbon atoms, preferably 11 or less carbon atoms, more preferably 5 or less carbon atoms, such as ethynyl groups; an alkoxy group having 1 or more carbon atoms, preferably 10 or less carbon atoms, more preferably 6 or less carbon atoms, such as methoxy group and ethoxy group; aryloxy groups having 4 or more carbon atoms, preferably 5 or more carbon atoms, preferably 25 or less carbon atoms, more preferably 14 or less carbon atoms, such as phenoxy, naphthoxy and pyridyloxy groups; an alkoxycarbonyl group having 2 or more carbon atoms, preferably 11 or less carbon atoms, more preferably 7 or less carbon atoms, such as a methoxycarbonyl group or an ethoxycarbonyl group; dialkylamino having 2 or more carbon atoms, preferably 20 or less carbon atoms, more preferably 12 or less carbon atoms, such as dimethylamino and diethylamino; diarylamino groups having 10 or more carbon atoms, preferably 12 or more carbon atoms, preferably 30 or less carbon atoms, more preferably 22 or less carbon atoms, such as a diphenylamino group, a xylylamino group, and an N-carbazolyl group; aralkylamino groups having 6 or more carbon atoms, more preferably 7 or more carbon atoms, still more preferably 25 or less carbon atoms, still more preferably 17 or less carbon atoms, such as phenylmethylamino group; acyl groups having 2 or more carbon atoms, preferably 10 or less carbon atoms, more preferably 7 or less carbon atoms, such as acetyl groups and benzoyl groups; halogen atoms such as fluorine atom and chlorine atom; haloalkyl groups having 1 or more, preferably 8 or less, more preferably 4 or less carbon atoms such as trifluoromethyl; alkylthio groups having 1 or more carbon atoms, preferably 10 or less carbon atoms, more preferably 6 or less carbon atoms, such as methylthio and ethylthio; arylthio groups having 4 or more carbon atoms, preferably 5 or more carbon atoms, preferably 25 or less carbon atoms, more preferably 14 or less carbon atoms, such as phenylthio, naphthylthio and pyridylthio groups; silyl groups having 2 or more carbon atoms, preferably 3 or more carbon atoms, preferably 33 or less carbon atoms, more preferably 26 or less carbon atoms, such as trimethylsilyl group and triphenylsilyl group; a siloxy group having 2 or more carbon atoms, preferably 3 or more carbon atoms, preferably 33 or less carbon atoms, more preferably 26 or less carbon atoms, such as a trimethylsiloxy group and a triphenylsiloxy group; cyano group; an aromatic hydrocarbon group having 6 or more carbon atoms, preferably 30 or less carbon atoms, more preferably 18 or less carbon atoms, such as a phenyl group and a naphthyl group; an aromatic heterocyclic group having 3 or more carbon atoms, preferably 4 or more carbon atoms, preferably 28 or less carbon atoms, more preferably 17 or less carbon atoms, such as a thienyl group and a pyridyl group.
Among the substituent groups W, alkyl groups or alkoxy groups are preferable from the viewpoint of improving solubility, and aromatic hydrocarbon groups or aromatic heterocyclic groups are preferable from the viewpoints of charge transport property and stability.
Particularly, among the polymer compounds having the repeating unit represented by the formula (11), a polymer compound having the repeating unit represented by the following formula (14) is preferable because hole injection/transport properties are very high.
[ 50]
(in the above formula (14), R 21 ～R 25 Each independently represents an optional substituent. R is R 21 ～R 25 Specific examples of the substituent of (a) are as described above [ substituent group W ]]The substituents described in the above are the same.
s and t each independently represent an integer of 0 to 5.
u, v, w each independently represent an integer of 0 to 4. )
Preferable examples of the aromatic tertiary amine polymer compound include polymer compounds containing a repeating unit represented by the following formula (15) and/or formula (16).
[ 51]
(Ar in the above formulas (15) and (16) 45 、Ar 47 And Ar is a group 48 Each independently represents a monovalent aromatic hydrocarbon group which may have a substituent or a monovalent aromatic heterocyclic group which may have a substituent. Ar (Ar) 44 And Ar is a group 46 Each independently represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent. R is R 41 ～R 43 Each independently represents a hydrogen atom or an optional substituent. )
Ar 45 、Ar 47 And Ar is a group 48 Specific examples, preferred examples, examples of substituents which may be present, examples of preferred substituents, and Ar 22 Identical Ar 44 And Ar is a group 46 Specific examples, preferred examples, examples of substituents which may be present, examples of preferred substituents, and Ar 11 、Ar 12 And Ar is a group 14 The same applies. As R 41 ～R 43 Preferably a hydrogen atom or the above-mentioned [ substituent group W ]]The substituent described in (b) is more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group or an aromatic heterocyclic group.
Hereinafter, preferred specific examples of the repeating units represented by the formulae (15) and (16) which can be applied to the present embodiment are given, but the present invention is not limited to these.
[ 52]
(electron-accepting Compound)
The composition for forming a hole injection layer preferably contains an electron accepting compound as a constituent material of the hole injection layer 3.
The electron-accepting compound is preferably a compound having an oxidizing ability and an ability to accept one electron from the hole-transporting material. Specifically, the electron accepting compound is preferably a compound having an electron affinity of 4.0eV or more, and more preferably a compound having an electron affinity of 5.0eV or more.
Examples of such an electron accepting compound include: one or more compounds selected from triarylboron compounds, metal halides, lewis acids, organic acids, onium salts, salts of aromatic amines and metal halides, salts of aromatic amines and Lewis acids, and the like. Further, specifically, examples of the electron accepting compound include: an organo-substituted onium salt such as 4-isopropyl-4' -methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate, etc. (International publication No. 2005/089024, international publication No. 2017/164268); high-valence inorganic compounds such as iron (III) chloride (JP-A-11-251067) and ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese patent application laid-open No. 2003-31365); fullerene derivatives; iodine; polystyrene sulfonate ion, alkylbenzenesulfonate ion, camphor sulfonate ion and other sulfonate ion.
The electron-accepting compound can improve the conductivity of the hole injection layer 3 by oxidizing the hole transport material.
(other constituent Material)
The material of the hole injection layer 3 may contain other components in addition to the hole transport material or the electron accepting compound described above, as long as the effect of the present invention is not significantly impaired.
(solvent)
At least one of the solvents of the composition for forming a hole injection layer used in the wet film forming method is preferably a compound capable of dissolving the constituent material of the hole injection layer 3.
When the composition for forming a hole injection layer is the second composition in this embodiment, the solvent is the first solvent component or the second solvent component in this embodiment.
Examples of the solvent include: ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like.
Examples of the ether solvent include: aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ethers such as 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethyl anisole and 2, 4-dimethyl anisole, and the like.
Examples of the ester solvent include: phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, and the like.
Examples of the aromatic hydrocarbon solvent include: toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3, 4-tetramethylbenzene, 1, 4-diisopropylbenzene, methylnaphthalene, and the like.
Examples of the amide solvent include: n, N-dimethylformamide, N-dimethylacetamide and the like.
In addition, dimethyl sulfoxide and the like can also be used.
Among them, aromatic esters and aromatic ethers are preferable.
These solvents may be used alone or in combination of two or more in any combination and ratio.
The concentration of the hole transport material in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired.
The concentration of the hole transport material in the composition for forming a hole injection layer is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, and even more preferably 0.5 wt% or more, from the viewpoint of uniformity of film thickness. The concentration of the hole transport material in the composition for forming a hole injection layer is preferably 70 wt% or less, more preferably 60 wt% or less, and still more preferably 50 wt% or less. The concentration is preferably small because it is less likely to cause uneven film thickness. In addition, the concentration is preferably large because defects are less likely to occur in the hole injection layer formed.
(formation of hole injection layer by wet film Forming method)
When the hole injection layer 3 is formed by the wet film formation method, a composition for forming a film (composition for forming a hole injection layer) is usually prepared by mixing a material constituting the hole injection layer 3 with an appropriate solvent (solvent for a hole injection layer), and the composition for forming a hole injection layer 3 is coated on a layer (typically, anode 2) corresponding to the lower layer of the hole injection layer by an appropriate method to form a film, followed by drying, thereby forming the hole injection layer 3.
(formation of hole injection layer 3 by vacuum deposition)
When the hole injection layer 3 is formed by vacuum deposition, the hole injection layer 3 may be formed as follows, for example.
One or two or more of the constituent materials of the hole injection layer 3 (the hole transporting material, the electron accepting compound, etc.) are placed in a crucible (when two or more materials are used, the crucible is placed), and the inside of the vacuum vessel is evacuated to about 10-4Pa by an appropriate vacuum pump. Thereafter, the crucibles are heated (when two or more materials are used, the respective crucibles are heated), evaporation is performed by controlling the evaporation amount (when two or more materials are used, evaporation is performed by controlling the evaporation amount independently), and a hole injection layer 3 is formed on the anode 2 of the substrate 1 disposed opposite to the crucibles. When two or more materials are used, the hole injection layer 3 may be formed by placing a mixture of these materials in a crucible, heating the mixture, and evaporating the mixture.
The vacuum degree at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired.
The vacuum degree at the time of vapor deposition is usually 0.1X10 -6 Torr(0.13×10 -4 Pa) or more, 9.0X10-6 Torr (12.0X10) -4 Pa) is below.
The vapor deposition rate is not limited as long as the effect of the present invention is not significantly impaired.
The evaporation rate is usuallyAbove and/or (II)>The following is given.
The film formation temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired.
The film formation temperature during vapor deposition is preferably 10 ℃ to 50 ℃.
[ hole transport layer ]
The hole transport layer 4 is a layer that transports from the anode 2 to the light-emitting layer 5. In general, the hole transport layer 4 is formed on the hole injection layer 3 when the hole injection layer 3 is present, and is formed on the anode 2 when the hole injection layer 3 is absent.
The method for forming the hole transport layer 4 may be a vacuum vapor deposition method or a wet film formation method, and is not particularly limited. From the viewpoint of lowering dark spots, the hole transport layer 4 is preferably formed by a wet film formation method.
The hole transport layer 4 contains a hole transport material. As the hole transport material forming the hole transport layer 4, a material which has high hole transport property and can transport injected holes efficiently is preferable. For this reason, the hole transport material forming the hole transport layer 4 is preferably small in ionization potential, high in transparency to visible light, large in hole mobility, excellent in stability, and less prone to occurrence of impurities that become traps at the time of manufacture or use. In many cases, the hole transport layer 4 is in contact with the light-emitting layer 5, and therefore it is preferable that the efficiency is reduced without quenching light emission from the light-emitting layer 5 or without forming an Exciplex (Exciplex) with the light-emitting layer 5.
The hole transport material of the hole transport layer 4 may be any material conventionally used as a constituent material of the hole transport layer 4. Examples of the material of the hole transport layer 4 include: arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, polycyclic aromatic derivatives with condensed rings, metal complexes, and the like. As the hole transport material for forming the hole transport layer 4, a hole transport material used in the composition for forming a hole injection layer may be used.
Examples of the hole transport material of the hole transport layer 4 include: polyvinylcarbazole derivatives, polyarylene amine derivatives (arylamine polymers), polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophene derivatives, poly (p-phenylene vinylene) derivatives, and the like.
These may be any of alternating copolymers, random copolymers, block polymers or graft copolymers. In addition, the polymer may be a so-called dendrimer or a polymer having branches in the main chain and 3 or more terminal portions.
Among them, the hole transport material of the hole transport layer 4 is preferably a polyarylene amine derivative or a polyarylene derivative.
Specific examples of the polyarylene amine derivative and polyarylene derivative include: and polyarylene amine derivatives and polyarylene derivatives described in JP-A2008-98619.
As the polyarylene amine derivative, an aromatic tertiary amine polymer compound represented by the formula (50) is preferably used.
When the hole transport layer 4 is formed by the wet film formation method, the hole transport layer forming composition is prepared in the same manner as the formation of the hole injection layer 3, and then the film is formed by the wet method and dried.
The hole transport layer-forming composition contains a solvent in addition to the hole transport material. The solvent used is the same as that used in the above-mentioned composition for forming a hole injection layer. The film formation conditions, drying conditions, and the like are the same as those in the case of forming the hole injection layer 3.
When the composition for forming a hole transport layer is the second composition in this embodiment, the solvent is the first solvent component or the second solvent component in this embodiment.
When the hole transport layer 4 is formed by the vacuum deposition method, the film formation conditions and the like are the same as those in the case of forming the hole injection layer 3.
Considering factors such as the penetration of the low molecular material into the light-emitting layer 5 and the swelling of the hole-transporting material, the film thickness of the hole-transporting layer 4 is usually 5nm or more, preferably 10nm or more, usually 300nm or less, preferably 200nm or less.
[ light-emitting layer ]
The light-emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes to which an electric field is applied, and serves as a main light-emitting source. The light-emitting layer 5 is typically formed on the hole transport layer 4 when the hole transport layer 4 is present, on the hole injection layer 3 when the hole transport layer 4 is absent and the hole injection layer 3 is present, and on the anode 2 when neither the hole transport layer 4 nor the hole injection layer 3 is present.
< Material for light-emitting layer >
The material for the light-emitting layer generally contains a light-emitting material and a charge transport material that becomes a host.
< luminescent Material >
As the light-emitting material, any known material used as a light-emitting material of an organic electroluminescent element can be generally used, and there is no particular limitation as long as a substance that emits light at a desired emission wavelength and has good light-emitting efficiency is used. The light-emitting material may be a fluorescent light-emitting material or a phosphorescent light-emitting material, but is preferably a phosphorescent light-emitting material from the viewpoint of internal quantum efficiency. Further preferably, the red light-emitting material and the green light-emitting material are phosphorescent light-emitting materials, and the blue light-emitting material is fluorescent light-emitting material.
When the second composition in this embodiment is a composition for forming a light-emitting layer, the following phosphorescent light-emitting material, fluorescent light-emitting material, and charge transporting material are preferably used.
< phosphorescent Material >
Phosphorescent light emitting materials refer to materials that exhibit luminescence from an excited triplet state. For example, a metal complex compound having Ir, pt, eu, or the like is typical thereof, and the material structure preferably includes a metal complex.
Among the metal complexes, phosphorescent organometallic complexes that emit light through a triplet state include: the compound contains a Wilnet-type complex or an organometallic complex, which is selected from metals of groups 7 to 11 of the long periodic Table (hereinafter, when not specifically described, it is referred to as "periodic Table") as a central metal.
Examples of such a phosphorescent material include: the phosphorescent materials described in International publication No. 2014/024889, international publication No. 2015-087961, international publication No. 2016/194784, and Japanese patent application laid-open No. 2014-074000. The compound represented by the following formula (201) or the compound represented by the following formula (205) is preferable, and the compound represented by the following formula (201) is more preferable.
[ 53]
In the formula (201), the ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ring A2 represents an aromatic heterocyclic structure which may have a substituent.
R 201 、R 202 Each independently is a structure represented by formula (202), "" represents a bonding position to ring A1 or ring A2. R is R 201 、R 202 Identical or different, in R 201 、R 202 Where plural are present, they may be the same or different, respectively.
Ar in formula (202) 201 、Ar 203 Each independently represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ar 202 Represents an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent.
Substituents bonded to the ring A1 of formula (201), substituents bonded to the ring A2, or substituents bonded to the ring A1 and substituents bonded to the ring A2 may be bonded to each other to form a ring.
B201-L200-B202 represents anionic bidentate ligands. B201 and B202 each independently represent a carbon atom, an oxygen atom or a nitrogen atom, and these atoms may also be ring-forming atoms. L200 represents a single bond or an atomic group which together with B201 and B202 constitutes a bidentate ligand. When there are plural B201-L200-B202, they may be the same or different.
In the formulas (201) and (202),
i1 and i2 each independently represent an integer of 0 to 12,
i3 represents a group substituted with Ar 202 The number of (2) is an integer of 0 or more of the upper limit,
i4 represents a substituent substituted for Ar 201 The number of (2) is an integer of 0 or more of the upper limit,
k1 and k2 each independently represent an integer of 0 or more having the number of rings A1 and A2 as an upper limit,
z represents an integer of 1 to 3.
(substituent)
When not specifically described, the substituent is preferably a group selected from the following substituent group S.
< substituent group S >
Alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 to 6 carbon atoms.
Alkoxy groups are preferably alkoxy groups having 1 to 20 carbon atoms, more preferably alkoxy groups having 1 to 12 carbon atoms, and still more preferably alkoxy groups having 1 to 6 carbon atoms.
The aryloxy group is preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, still more preferably an aryloxy group having 6 to 12 carbon atoms, particularly preferably an aryloxy group having 6 carbon atoms.
The heteroaryloxy group is preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms.
Alkylamino is preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms.
An arylamino group is preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms.
Aralkyl group is preferably an aralkyl group having 7 to 40 carbon atoms, more preferably an aralkyl group having 7 to 18 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.
The heteroarylalkyl group is preferably a heteroarylalkyl group having 7 to 40 carbon atoms, more preferably a heteroarylalkyl group having 7 to 18 carbon atoms.
Alkenyl is preferably an alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, still more preferably an alkenyl group having 2 to 8 carbon atoms, and particularly preferably an alkenyl group having 2 to 6 carbon atoms.
Alkynyl is preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms.
Aryl is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, still more preferably an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 14 carbon atoms.
Heteroaryl is preferably a heteroaryl group having 3 to 30 carbon atoms, more preferably a heteroaryl group having 3 to 24 carbon atoms, still more preferably a heteroaryl group having 3 to 18 carbon atoms, and particularly preferably a heteroaryl group having 3 to 14 carbon atoms.
Alkylsilyl groups, preferably alkylsilyl groups having 1 to 20 carbon atoms in the alkyl group, more preferably alkylsilyl groups having 1 to 12 carbon atoms in the alkyl group.
Arylsilyl groups, preferably arylsilyl groups having 6 to 20 carbon atoms in the aryl group, more preferably arylsilyl groups having 6 to 14 carbon atoms in the aryl group.
Alkylcarbonyl group, preferably alkylcarbonyl group having 2 to 20 carbon atoms.
Arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms.
Hydrogen atom, heavy hydrogen atom, fluorine atom, cyano group or-SF 5.
More than one hydrogen atom of the group of substituents S above may be substituted with a fluorine atom, or more than one hydrogen atom may be substituted with a heavy hydrogen atom.
Unless otherwise specified, aryl is an aromatic hydrocarbon ring and heteroaryl is an aromatic heterocyclic ring.
Among the above substituent groups S, preferred are alkyl, alkoxy, aryloxy, arylamino, aralkyl, alkenyl, aryl, heteroaryl, alkylsilyl, arylsilyl and these A group in which one or more hydrogen atoms of the group are replaced by fluorine atoms, a fluorine atom, a cyano group or-SF 5 ，
Further preferred are alkyl, alkoxy, aryloxy, arylamino, aralkyl, alkenyl, aryl, heteroaryl, alkylsilyl, arylsilyl and groups in which one or more hydrogen atoms of these groups are replaced with fluorine atoms, cyano groups or-SF 5,
more preferred are alkyl, arylamino, aralkyl, alkenyl, aryl, heteroaryl and groups in which one or more hydrogen atoms of these groups are replaced by fluorine atoms, cyano groups or-SF 5 ，
Particularly preferred are alkyl, arylamino, aralkyl, alkenyl, aryl, heteroaryl,
most preferred are alkyl, arylamino, aralkyl, aryl, heteroaryl groups.
These substituent groups S may further have a substituent selected from the substituent groups S as a substituent. Preferred groups, more preferred groups, further preferred groups, particularly preferred groups, most preferred groups of substituents which may be present are the same as the preferred groups of substituent group S.
(Ring A1)
Ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
The aromatic hydrocarbon ring is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, benzene ring, naphthalene ring, anthracene ring, triphenyl (triphenyl) ring, acenaphthene ring, fluoranthene ring, fluorene ring are preferable.
The aromatic heterocyclic ring is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms, which contains any one of a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom. Further preferred are furan ring, benzofuran ring, thiophene ring and benzothiophene ring.
The ring A1 is more preferably a benzene ring, naphthalene ring, or fluorene ring, particularly preferably a benzene ring or fluorene ring, and most preferably a benzene ring.
(Ring A2)
Ring A2 represents an aromatic heterocyclic structure which may have a substituent.
The aromatic heterocyclic ring is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms, which contains any one of a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom.
Specifically, there may be mentioned: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, preferably pyridine ring, pyrazine ring, pyrimidine ring, imidazole ring, benzothiazole ring, benzoxazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, more preferably pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, most preferably pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, quinoxaline ring, quinazoline ring.
(combination of Ring A1 and Ring A2)
The preferred combinations of the ring A1 and the ring A2 are (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring-quinazoline ring), (benzene ring-benzothiazole ring), (benzene ring-imidazole ring), (benzene ring-pyrrole ring), (benzene ring-diazole ring) and (benzene ring-thiophene ring) when referred to as (ring A1-ring A2).
(substituents of Ring A1 and Ring A2)
The substituents which the rings A1 and A2 may have may be arbitrarily selected, but are preferably one or more substituents selected from the substituent group S.
(Ar 201 、Ar 202 、Ar 203 )
Ar 201 、Ar 203 Each independently represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ar 202 Represents an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent.
Ar 201 、Ar 202 、Ar 203 When any one of the aromatic hydrocarbon ring structures may have a substituent, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, benzene rings are preferableNaphthalene ring, anthracene ring, triphenyl (triphenylyl) ring, acenaphthene ring, fluoranthene ring, fluorene ring, more preferably benzene ring, naphthalene ring, fluorene ring, most preferably benzene ring.
Ar 201 、Ar 202 When any one of the benzene rings which may have a substituent is a benzene ring, at least one benzene ring is preferably bonded to an adjacent structure at an ortho-position or a meta-position, and more preferably at least one benzene ring is bonded to an adjacent structure at a meta-position.
Ar 201 、Ar 202 、Ar 203 When any one of the fluorene rings is a fluorene ring which may have a substituent, the positions 9 and 9' of the fluorene ring preferably have a substituent, or are bonded to an adjacent structure.
Ar 201 、Ar 202 、Ar 203 When any one of the aromatic heterocyclic structures may have a substituent, the aromatic heterocyclic structure is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms and containing any one of a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom, and specifically, examples thereof include: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, preferably pyridine ring, pyrimidine ring, triazine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring.
Ar 201 、Ar 202 、Ar 203 When any of the carbazole rings which may have a substituent is used, it is preferable that the carbazole ring has a substituent at the N-position or is bonded to an adjacent structure.
Ar 202 In the case of an aliphatic hydrocarbon structure which may have a substituent, the aliphatic hydrocarbon structure is preferably an aliphatic hydrocarbon structure having a linear, branched or cyclic structure, and the number of carbon atoms is preferably 1 to 24, more preferably 1 to 12, and still more preferably 1 to 8.
(i1、i2、i3、i4、k1、k2)
i1 and i2 each independently represent an integer of 0 to 12, preferably an integer of 1 to 12, more preferably an integer of 1 to 8, and even more preferably an integer of 1 to 6. Within this range, an improvement in solubility or an improvement in charge transport property can be expected.
i3 preferably represents an integer of 0 to 5, more preferably an integer of 0 to 2, and still more preferably 0 or 1.
i4 preferably represents an integer of 0 to 2, and more preferably 0 or 1.
k1 and k2 each independently preferably represent an integer of 0 to 3, more preferably an integer of 1 to 3, still more preferably 1 or 2, and particularly preferably 1.
(Ar 201 、Ar 202 、Ar 203 Preferred substituents of (2)
Ar 201 、Ar 202 、Ar 203 The substituent which may be optionally selected, but is preferably one or more substituents selected from the substituent group S described above, and the preferred group is also as shown in the substituent group S, but is more preferably unsubstituted (hydrogen atom), alkyl group, aryl group, particularly preferably unsubstituted (hydrogen atom), alkyl group, most preferably unsubstituted (hydrogen atom) or tert-butyl group. Preferably tert-butyl in the presence of Ar 203 When substituted for Ar 203 In the absence of Ar 203 When substituted for Ar 202 In the absence of Ar 202 And Ar is a group 203 When substituted for Ar 201 。
(preferred modes of the Compound represented by the formula (201))
The compound represented by the above formula (201) is preferably a compound satisfying any one or more of the following (I) to (IV).
(I) Phenylene-linked
The structure represented by formula (202) is preferably a structure having a group in which benzene rings are linked, that is, a benzene ring structure, i1 is an integer of 1 to 6, and at least one of the benzene rings is bonded to an adjacent structure in the ortho or meta position.
With such a structure, improvement in solubility and improvement in charge transport property is expected.
(II) (phenylene) -aralkyl (alkyl)
Having a structure in which an aromatic hydrocarbon group or an aromatic heterocyclic group having an alkyl group or an aralkyl group bonded thereto, i.e., ar, is present in the ring A1 or the ring A2 201 Is aromatic hydrocarbon structure or aromatic heterocyclic structureI1 is an integer of 1 to 6, ar 202 Is an aliphatic hydrocarbon structure, i2 is an integer of 1 to 12, preferably an integer of 3 to 8, ar 203 Is a benzene ring structure, i3 is a structure of 0 or 1, preferably Ar 201 The aromatic hydrocarbon structure is more preferably a structure in which 1 to 5 benzene rings are bonded, and still more preferably 1 benzene ring.
With such a structure, improvement in solubility and improvement in charge transport property is expected.
(III) dendrites
Structures in which dendrites are bonded to ring A1 or ring A2, e.g. Ar 201 、Ar 202 Is of benzene ring structure, ar 203 Is biphenyl or terphenyl, i1, i2 are integers from 1 to 6, i3 is 2, j is 2.
With such a structure, improvement in solubility and improvement in charge transport property is expected.
(IV)B201-L200-B202
The structure represented by B201-L200-B202 is preferably a structure represented by the following formula (203) or the following formula (204).
[ 54]
In the formula (203), R 211 、R 212 、R 213 Each independently represents a substituent.
In the formula (204), the ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom which may have a substituent. Ring B3 is preferably a pyridine ring.
(preferred phosphorescent materials)
The phosphorescent material represented by the above formula (201) is not particularly limited, and the following materials are preferable.
[ 55]
[ 56]
In addition, a phosphorescent material represented by the following formula (205) is also preferable.
[ 57]
(in the formula (205), M 2 Represents a metal, and T represents a carbon atom or a nitrogen atom. R is R 92 ～R 95 Each independently represents a substituent. But where T is a nitrogen atom, there is no R 94 And R is 95 。)
In the formula (205), M is 2 Specific examples of (a) include: metals selected from groups 7 to 11 of the periodic table. Among them, preferable examples are: ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold, and particularly preferred are divalent metals such as platinum and palladium.
In the formula (205), R is 92 And R is 93 Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.
When T is a carbon atom, R 94 And R is 95 Each independently represents a group represented by R 92 And R is 93 Substituents indicated by the same illustrations. In addition, when T is a nitrogen atom, R directly bonded to T is absent 94 Or R is 95 . In addition, R 92 ～R 95 May have a substituent. The substituent may be the above substituent. Further, R 92 ～R 95 Any two or more of the groups may be linked to each other to form a ring.
(molecular weight)
The molecular weight of the phosphorescent material is preferably 5000 or less, more preferably 4000 or less, particularly preferably 3000 or less. The molecular weight of the phosphorescent material is preferably 800 or more, more preferably 1000 or more, and even more preferably 1200 or more. In this molecular weight range, it is considered that a light-emitting layer having high light-emitting efficiency can be obtained in which phosphorescent light-emitting materials are uniformly mixed with a charge transport material without aggregation.
The phosphorescent material and the formed light-emitting layer are preferably large in molecular weight from the viewpoint of high Tg, melting point, decomposition temperature, etc., excellent heat resistance, and less liable to cause a decrease in film quality due to gas generation, recrystallization, molecular migration, etc., an increase in impurity concentration accompanying thermal decomposition of the material, etc. On the other hand, from the viewpoint of easy purification of the organic compound, the phosphorescent light-emitting material is preferably small in molecular weight.
< Charge transport Material >
The charge transport material used in the light-emitting layer is a material having a skeleton excellent in charge transport property, and is preferably selected from an electron transport material, a hole transport material, and a bipolar material capable of transporting both electrons and holes.
As a skeleton excellent in charge transport property, concretely, there is given: aromatic structures, aromatic amine structures, triarylamine structures, dibenzofuran structures, naphthalene structures, phenanthrene structures, phthalocyanine structures, porphyrin structures, thiophene structures, benzyl phenyl structures, fluorene structures, quinacridone structures, triphenylene structures, carbazole structures, pyrene structures, anthracene structures, phenanthroline structures, quinoline structures, pyridine structures, pyrimidine structures, triazine structures, oxadiazole structures, imidazole structures, or the like.
The electron-transporting material is more preferably a compound having a pyridine structure, a pyrimidine structure, or a triazine structure, and further preferably a compound having a pyrimidine structure or a triazine structure, from the viewpoint of excellent electron-transporting properties and relatively stable structure.
The hole transporting material is a compound having a structure excellent in hole transporting property, and among the above-mentioned center skeletons excellent in charge transporting property, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure is preferable as the structure excellent in hole transporting property, and a carbazole structure, a dibenzofuran structure, or a triarylamine structure is more preferable.
The charge transport material used in the light-emitting layer preferably has a condensed ring structure of three or more rings, and more preferably is a compound having a condensed ring structure of 2 or more three or more rings or a compound having at least 1 condensed ring of five or more rings. By adding these compounds, the rigidity of the molecule increases, and the effect of suppressing the degree of molecular movement of the thermal response is easily obtained. Further, from the viewpoints of charge transport property and durability of materials, it is preferable that the condensed rings of three or more rings and the condensed rings of five or more rings have an aromatic hydrocarbon ring or an aromatic heterocyclic ring.
Specific examples of the condensed ring structure having three or more rings include: an anthracene structure, a phenanthrene structure, a pyrene structure,A structure, a naphthacene structure, a triphenylene structure, a fluorene structure, a benzofluorene structure, an indenofluorene structure, an indolofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, a dibenzothiophene structure, and the like. From the viewpoint of charge transport property and solubility, at least one selected from the group consisting of a phenanthrene structure, a fluorene structure, an indenofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure is preferable, and from the viewpoint of durability to electric charges, a carbazole structure or an indolocarbazole structure is more preferable.
In this embodiment, from the viewpoint of durability to electric charges of the organic electroluminescent element, it is preferable that at least one of the charge transport materials of the light-emitting layer is a material having a pyrimidine skeleton or a triazine skeleton.
The charge transport material of the light-emitting layer is preferably a polymer material from the viewpoint of excellent flexibility. The light-emitting layer formed using a material excellent in flexibility is preferably used as a light-emitting layer of an organic electroluminescent element formed on a flexible substrate.
When the charge transport material contained in the light-emitting layer is a polymer material, the weight average molecular weight is preferably 5,000 or more, more preferably 10,000 or more, preferably 1,000,000 or less, more preferably 500,000 or less, and further preferably 100,000 or less.
In addition, the charge transport material of the light-emitting layer is preferably low-molecular from the viewpoints of ease of synthesis and purification, ease of design of electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in a solvent.
When the charge transport material contained in the light-emitting layer is a low-molecular material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, most preferably 2,000 or less, preferably 300 or more, more preferably 350 or more, and further preferably 400 or more.
< fluorescent luminescent Material >
The fluorescent light-emitting material is not particularly limited, and is preferably a compound represented by the following formula (211).
[ 58]
Ar in the above formula (211) 241 Represents an aromatic hydrocarbon condensed ring structure which may have a substituent, ar 242 、Ar 243 Each independently represents an alkyl group which may have a substituent, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a group formed by bonding these groups. n41 is an integer of 1 to 4.
Ar 241 An aromatic hydrocarbon condensed ring structure having 10 to 30 carbon atoms is preferable, and specific ring structures include: naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, tetracene,Perylene, and the like. />
Ar 241 More preferably an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms, and specific ring structures include: acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, naphthacene,Perylene.
Ar 241 Further preferably having 16 to 18 carbon atomsSpecific examples of the aromatic hydrocarbon condensed ring structure include: fluoranthene, pyrene,
n41 is an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 1 or 2, and most preferably 2.
As Ar 242 、Ar 243 The alkyl group of (a) is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms.
As Ar 242 、Ar 243 The aromatic hydrocarbon group of (a) is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms, and most preferably a phenyl group or a naphthyl group.
As Ar 242 、Ar 243 The aromatic heterocyclic group of (a) is preferably an aromatic heterocyclic group having 3 to 30 carbon atoms, more preferably an aromatic heterocyclic group having 5 to 24 carbon atoms, particularly preferably a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, and more preferably a dibenzofuranyl group.
Ar 241 、Ar 242 、Ar 243 The substituent which may be provided is preferably a group selected from the above substituent group S, more preferably a hydrocarbon group contained in the substituent group S, and still more preferably a hydrocarbon group in the group preferred as the substituent group S.
The charge transport material used together with the fluorescent light-emitting material is not particularly limited, and is preferably a material represented by the following formula (212).
[ 59]
In the above formula (212), R 251 、R 252 Each independently is a structure represented by the following formula (213), R 253 Represents a substituent, R 253 When there are plural, these are the same or different, and n43 is an integer of 0 to 8.
[ chemical 60]
In the above formula (213), ar represents a bond to the anthracycline of the formula (212) 254 、Ar 255 Each independently represents an aromatic hydrocarbon structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent, ar 254 、Ar 255 When a plurality of the compounds are present, these are the same or different, n44 is an integer of 1 to 5, and n45 is an integer of 0 to 5.
Ar 254 The aromatic hydrocarbon structure of a single ring or condensed ring having 6 to 30 carbon atoms which may have a substituent is preferable, and the aromatic hydrocarbon structure of a single ring or condensed ring having 6 to 12 carbon atoms which may have a substituent is more preferable.
Ar 255 The aromatic hydrocarbon structure of a single ring or condensed ring having 6 to 30 carbon atoms which may have a substituent, or the aromatic heterocyclic structure of a condensed ring having 6 to 30 carbon atoms which may have a substituent is preferable. Ar (Ar) 255 More preferably, the aromatic hydrocarbon structure may have a substituted monocyclic or condensed ring having 6 to 12 carbon atoms or the aromatic heterocyclic structure may have a substituted condensed ring having 6 to 12 carbon atoms.
n44 is preferably an integer of 1 to 3, more preferably 1 or 2.
n45 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2.
Substituent R 253 、Ar 254 And Ar is a group 255 The substituent which may be present is preferably a group selected from the above substituent group S. More preferably, the hydrocarbon group contained in the substituent group S, and still more preferably, the hydrocarbon group contained in the group preferable as the substituent group S.
The weight molecular weight of the fluorescent light-emitting material and the charge transport material is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less. Further, it is preferably 300 or more, more preferably 350 or more, and further preferably 400 or more.
[ hole blocking layer ]
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer which further serves as a layer of the electron transport layer that blocks holes moving from the anode 2 from reaching the cathode 9. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to contact the interface on the cathode 9 side of the light emitting layer 5.
The hole blocking layer 6 has a function of blocking holes moving from the anode 2 from reaching the cathode 9 and a function of effectively transporting electrons injected from the cathode 9 in the direction of the light emitting layer 5.
The physical properties required for the material constituting the hole blocking layer 6 include: high electron mobility, low hole mobility, large energy gap (difference between HOMO and LUMO), high excited triplet level (T1), and the like.
Examples of the material of the hole blocking layer 6 satisfying such a condition include: mixed ligand complexes such as bis (2-methyl-8-hydroxyquinoline) (phenol) aluminum, bis (2-methyl-8-hydroxyquinoline) (triphenylsilanol) aluminum, metal complexes such as bis (2-methyl-8-hydroxyquinoline) aluminum-mu-oxo-bis- (2-methyl-8-hydroxyquinoline) aluminum binuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives (JP-A-11-242996), triazole derivatives such as 3- (4-biphenyl) -4-phenyl-5 (4-t-butylphenyl) -1,2, 4-triazole (JP-A-7-41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. Further, a compound having a pyridine ring substituted at least at the 1-2, 4, 6-positions described in International publication No. 2005/022962 is also preferable as a material of the hole blocking layer 6.
There is no limitation on the formation method of the hole blocking layer 6. The hole blocking layer 6 may be formed by a wet film forming method, a vapor deposition method, or other methods.
The film thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired. The film thickness of the hole blocking layer 6 is usually 0.3nm or more, preferably 0.5nm or more, usually 100nm or less, preferably 50nm or less.
[ Electron transport layer ]
The electron transport layer 7 is a layer for transporting electrons provided between the light emitting layer 5 and the cathode 9.
As the electron transport material of the electron transport layer 7, a compound having high electron injection efficiency from the cathode 9 or an adjacent layer on the cathode 9 side and having high electron mobility so as to be able to efficiently transport the injected electrons is generally used.
Examples of the compound satisfying such a condition include: metal complexes such as aluminum complexes and lithium complexes of 8-hydroxyquinoline (Japanese patent application laid-open No. 59-194393), metal complexes of 10-hydroxybenzo [ h ] quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, tribenzimidazolylbenzene (U.S. Pat. No. 5645948), quinoxaline compounds (Japanese patent application laid-open No. 6-207169), phenanthroline derivatives (Japanese patent application laid-open No. 5-331459), 2-t-butyl-9, 10-N, N' -dicyanoanthraquinone diimine, triazine compound derivatives, N-type hydrogenated amorphous silicon carbide, N-type zinc sulfide, N-type zinc selenide and the like.
As the electron transport material used in the electron transport layer 7, an electron transport organic compound represented by a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is preferably doped with an alkali metal such as sodium, potassium, cesium, lithium or rubidium (described in japanese patent application laid-open No. 10-270171, japanese patent application laid-open No. 2002-100478 or japanese patent application laid-open No. 2002-100482), since both of the electron injection transport property and the excellent film quality can be achieved. Further, it is also effective to dope the electron-transporting organic compound with an inorganic salt such as lithium fluoride or cesium carbonate.
There is no limitation on the method of forming the electron transport layer 7. The electron transport layer 7 may be formed by a wet film forming method, a vapor deposition method, or other methods.
The film thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired. The film thickness of the electron transport layer 7 is usually 1nm or more, preferably 5nm or more, usually 300nm or less, preferably 100nm or less.
[ Electron injection layer ]
In order to efficiently inject electrons injected from the cathode 9 into the light-emitting layer 5, an electron injection layer 8 may be provided between the electron transport layer 7 and the cathode 9 described later. The electron injection layer 8 is composed of an inorganic salt or the like.
Examples of the material of the electron injection layer 8 include: lithium fluoride (LiF), magnesium fluoride (MgF) 2 ) Lithium oxide (Li) 2 O), cesium (II) carbonate (CsCO) 3 ) Et al (ref Applied Physics Letters,1997, vol.70, pp.152; japanese patent laid-open No. 10-74586; IEEE Transactions on Electron Devices,1997, vol.44, pp.1245; SID 04digest, pp.154, etc.).
The electron injection layer 8 is preferably used as an extremely thin film in order to perform electron injection efficiently because it does not have charge transport properties in many cases, and its film thickness is usually 0.1nm or more, preferably 5nm or less.
[ cathode ]
The cathode 9 is an electrode that functions to inject electrons into a layer on the light-emitting layer 5 side.
The cathode 9 is usually made of: metals such as aluminum, gold, silver, nickel, palladium, and platinum, metal oxides such as indium and/or tin oxides, metal halides such as copper iodide, carbon black, and conductive polymers such as poly (3-methylthiophene), polypyrrole, and polyaniline. Among these, metals having a low work function are preferable for efficient electron injection, and for example, suitable metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys of these metals are used. Specific examples include: low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy, and the like.
The material of the cathode 9 may be used alone, or two or more kinds may be used in any combination and ratio.
The film thickness of the cathode 9 varies depending on the required transparency. When transparency is required, the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness of the cathode 9 is usually 5nm or more, preferably 10nm or more, usually 1000nm or less, preferably about 500nm or less. In the case of being opaque, the thickness of the cathode 9 may be arbitrary, and the cathode may be the same as the substrate.
Different conductive materials may be laminated on the cathode 9.
For example, it is preferable to further laminate a metal layer having a high work function and being stable to the atmosphere on the cathode for the purpose of protecting the cathode containing a metal having a low work function such as an alkali metal such as sodium or cesium, an alkaline earth metal such as barium or calcium, and the like, because the stability of the element is increased. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum, etc. are used, for example. These materials may be used alone, or two or more of them may be used in any combination and ratio.
[ other layers ]
The organic electroluminescent element in the present embodiment may have other configurations within a range not departing from the gist thereof. For example, any layer other than the above-described layers may be provided between the anode 2 and the cathode 9 as long as the performance is not impaired, and unnecessary layers among the above-described layers may be omitted.
In the layer structure described above, the components other than the substrates may be stacked in reverse order. For example, in the layer structure of fig. 1, other components may be provided on the substrate 1 in the order of the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the hole injection layer 3, and the anode 2.
The organic electroluminescent element in the present embodiment may be configured as a single organic electroluminescent element, may be applied to a configuration in which a plurality of organic electroluminescent elements are arranged in an array, or may be applied to a configuration in which an anode and a cathode are arranged in an X-Y matrix.
The above-described respective layers may contain components other than those described as materials as long as the effects of the present invention are not significantly impaired.
< organic electroluminescent device >
Two or more organic electroluminescent elements that emit light in different colors may be provided to manufacture an organic EL display device, an organic EL lighting device, or the like. In this organic electroluminescent device, at least one, preferably all, of the organic electroluminescent elements are provided as the organic electroluminescent element in the present embodiment, whereby a high-quality organic electroluminescent device can be provided.
< organic EL display device >
The type or structure of the organic EL display device using the organic electroluminescent element in the present embodiment is not limited, and the organic electroluminescent element in the present embodiment may be used for assembly in a conventional manner.
For example, an organic EL display device can be formed by a method described in "organic EL display" (published by Ohm corporation in 8 months and 20 days of 16 years, ren Jingshi, dakubo, and village Tian Yingxing).
Examples
< Synthesis of aromatic amine Polymer 1 >
[ chemical 61]
The aromatic amine polymer 1 represented by the above formula was synthesized by a conventionally known method. The weight average molecular weight was 29140, the molecular weight distribution represented by the weight average molecular weight/number average molecular weight was 1.25, and the glass transition temperature was 229 ℃.
< formation of first functional film >
A glass substrate having a thickness of 0.7mm and a thickness of 25X 37mm was subjected to UV/ozone cleaning.
A first composition obtained by dissolving the aromatic amine polymer 1 produced as described above as a first functional material in anisole solvent was prepared, and a film was formed on the entire surface of the glass substrate by spin coating. The content of the aromatic amine polymer in the first composition was 3.2 mass%. Putting it in N 2 The film was heated at 220℃for 30 minutes under an atmosphere to obtain an insoluble first functional film having a film thickness of 100 nm.
< impregnation of first functional film >
130. Mu.L of the solvent component described in Table 1 as the second composition was dropped onto the first functional film. After the glass substrate was kept at 23℃under an atmospheric environment for the time (5 to 15 minutes) described in Table 1, the solvent was removed by spin-coating the glass substrate at 3000rpm for 2 minutes. Then, the mixture was dried in a vacuum drier heated to 30℃for 3 minutes or more. The vacuum degree is 10Pa or lower. Then, the solvent was completely removed by heating at 100℃for 1 minute and at 230℃for 10 minutes.
The holding time (immersion time), the viscosity of the solvent component at 23 ℃ and the hansen solubility parameter δp of the solvent component are shown in table 1, and the structural formulas of the respective solvent components are also shown.
The second composition contains only a solvent component. Therefore, the viscosity of the second composition at 23℃was the same as that of the second composition in the case of one solvent component, namely examples 1 to 8 and comparative examples 1 to 4. Here, since the viscosity of example 8 is larger than 15mpa·s, it is preferable to make the viscosity of the second composition 15mpa·s or less by adding a low-viscosity solvent, reducing the concentration of the solid content in the second composition, using a low-molecular weight solid content whose viscosity is not easily increased, or the like, when the organic semiconductor element is actually obtained.
In the case of the two solvent components, i.e., examples 9 and 10, the viscosity of the second composition was determined by the viscosity of the two solvent components and the content ratio thereof.
< measurement of film thickness of first functional film >
The film thickness of the first functional film was determined by the reflection spectroscopic film thickness meter OPTM.
The reflectance spectra of 8 positions in the first functional film plane were measured, the measured positions were unified among the substrates, and the reflectance spectra before and after the above < immersion of the first functional film > were measured.
By changing the concentration of the aromatic amine polymer in the first composition and the spin-coating rotation speed, 9 kinds of thin films having different film thicknesses of the first functional film were prepared, and a calibration optical model was generated based on the correlation between the stepped film thickness and the reflectance spectrum measured by KOSAKA Surfcorder. The optical film thickness at 8 positions was calculated from the measured reflection spectrum using an optical model.
< calculation of residual film Rate >
The film residue ratio at 8 positions in each horizontal plane and in each plane was calculated by dividing the film thickness change of the first functional film before and after the first functional film dipping > by the average film residue ratio at 8 positions, as a standard film residue ratio. The results are shown in Table 1.
Although a solvent composed of at least one of the first solvent component and the second solvent component is used as the second composition, the film residue ratio tends to be the same when a second functional film further containing a second functional material is provided.
< solvent determination formula >
As a reference for judging suitability of the solvent component monomer, the values represented by the left side of the following relational expression (a) were calculated for the respective solvent components used in examples 1 to 8 and comparative examples 1 to 4. The results are shown in the item of the judgment formula (a) in table 1.
32X viscosity-4.3X theoretical surface area +5.4X volume-boiling point >150 … (A)
The theoretical surface area and volume in the above relation (A) are expressed by A.Klamt, "COSMO-RS: calculated from the methods described in quantum chemistry to fluid phase thermodynamics and drug design (From Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design) ", elsevier Science, first edition (9/29/2005).
If the above relation (a) is satisfied, that is, if the value calculated as the left side is greater than 150, it can be judged that the solvent component is suitable as the first solvent component. In addition, "-" in table 1 indicates that it is not calculated.
< flow activation energy >
The flow activation energy is E in the following formula (I). The viscosity of the solvent was measured by changing the temperature, the viscosity log with respect to the reciprocal of the temperature was plotted, and the flow activation energy was obtained from the slope thereof.
η＝Aexp(E/RT)(I)
η: viscosity (cP)
A: constant (constant)
E: flow activation energy (kJ/mol)
R: gas constant (8.314J/K/mol)
T: temperature (K)
In the present invention, the viscosity of the solvent was measured using an E-type viscometer RE85L (manufactured by eastern machine industry) at 23℃using a cone rotation speed of 20rpm to 100 rpm.
TABLE 1
TABLE 1
From the results shown in Table 1, it was found that the dissolution of the first functional film was suppressed even when the immersion time was 15 minutes by using the first solvent component having a viscosity of 3 mPas or more and/or a flow activation energy of 17kJ/mol or more at 23 ℃.
This shows that it is possible to select a solvent component that inhibits the dissolution of the first functional material, which is also associated with the value represented by the left hand side of relation (a). The residual film ratio was greater than 100% because of a few deviations from the optical model for optical film thickness fitting due to the variation in optical characteristics.
In example 9 and example 10, which contained the first solvent component of example 5 and the second solvent component of comparative example 5, the residual film rate was high, and it was found that the dissolution of the first functional material was suppressed even when the second solvent was present by containing an appropriate solvent as the first solvent.
[ 62]
The various embodiments have been described above with reference to the drawings, but it is needless to say that the present invention is not limited to the examples. It is apparent to those skilled in the art that various modifications and corrections can be made within the scope of the claims, and these are of course within the technical scope of the present invention. The components of the above embodiments may be arbitrarily combined within a range not departing from the gist of the invention.
The present application is based on japanese patent application No. 2021-076580 (japanese patent application No. 2021-076580), filed on 4/28 of 2021, the contents of which are incorporated herein by reference.

Claims (17)

1. A method for manufacturing an organic semiconductor element, comprising the steps of:
a step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
the first composition contains a first functional material,
the first functional material comprises an aromatic amine polymer having a weight average molecular weight of 15000 or more and 50000, the aromatic amine polymer not having any one of a crosslinking group, a polymerization group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a viscosity of 3 mPas or more at 23 ℃.
2. The method for manufacturing an organic semiconductor device according to claim 1, wherein,
the solvent further comprising a second solvent component having a viscosity of less than 3 mPas at 23 ℃,
the first solvent component has a flow activation energy of 17kJ/mol or more.
3. A method for manufacturing an organic semiconductor element, comprising the steps of:
a step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
the first composition contains a first functional material,
the first functional material comprises an aromatic amine polymer without any of a crosslinking group, a polymeric group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a flow activation energy of 17kJ/mol or more,
the solvent also contains a second solvent component having a viscosity of less than 3 mPa-s at 23 ℃.
4. The method for producing an organic semiconductor element according to claim 3, wherein the weight average molecular weight of the aromatic amine polymer is 15000 or more and 50000 or less.
5. A method for manufacturing an organic semiconductor element, comprising the steps of:
a step of applying a first composition and heating to provide a first functional film;
a step of applying a second composition to the first functional film to provide a second functional film,
The first composition contains a first functional material,
the first functional material comprises an aromatic amine polymer without any of a crosslinking group, a polymeric group, and a leaving soluble group,
the second composition contains a solvent and has a viscosity of 15 mPas or less at 23 ℃,
the solvent contains at least one first solvent component having a viscosity of 3 mPas or more at 23 ℃,
the solvent further comprising a second solvent component having a viscosity of less than 3 mPas at 23 ℃,
the first solvent component has a flow activation energy of 17kJ/mol or more.
6. The method for producing an organic semiconductor element according to any one of claims 1 to 5, wherein the aromatic amine polymer has a repeating unit represented by the following formula (50),
in the formula (50), the amino acid sequence of the compound,
Ar 51 represented by the choice of with or withoutA group formed by connecting one group or a plurality of groups of at least one of an aromatic hydrocarbon group and an aromatic heterocyclic group with or without a substituent, wherein the substituent is a crosslinking group, a polymeric group or a leaving soluble group;
Ar 52 represents a divalent group formed by linking one or more groups selected from at least one of a divalent aromatic hydrocarbon group with or without a substituent and a divalent aromatic heterocyclic group with or without a substituent, the linking being performed directly or via a linking group, the substituents being each a group other than a crosslinking group, a polymeric group or a leaving soluble group;
Ar 51 And Ar is a group 52 Directly or via a linker to form a ring, or not;
Ar 51 、Ar 52 without any of crosslinking groups, polymeric groups, and leaving soluble groups.
7. The method for manufacturing an organic semiconductor element according to claim 6, wherein the aromatic amine polymer comprises a structure in which a plurality of benzene ring structures are connected in para-position to a main chain, and at least one of the plurality of benzene ring structures has a substituent in at least one of 2 carbon atoms located in the vicinity of a carbon atom bonded to an adjacent benzene ring structure.
8. The method for manufacturing an organic semiconductor element according to claim 6 or 7, wherein the repeating unit represented by formula (50) is represented by the following formula (54),
in the formula (54), the amino acid sequence of the compound,
Ar 51 ar in the formula (50) 51 The same is true of the fact that,
x is-C (R) 7 )(R 8 )-、-N(R 9 ) -or-C (R) 11 )(R 12 )-C(R 13 )(R 14 )-，
R 1 And R is 2 Each independently is an alkyl group with or without a substituent which is a crosslinking group, a polymeric group, or a group other than a leaving soluble group,
R 7 ～R 9 and R is 11 ～R 14 Each independently is a hydrogen atom, an alkyl group with or without a substituent, an aralkyl group with or without a substituent, or an aromatic hydrocarbon group with or without a substituent, which are each a crosslinking group, a polymerization group, or a group other than a leaving soluble group,
a and b are each independently integers from 0 to 4,
c is an integer of 1 to 3,
d is an integer of 0 to 4,
at R 1 Where there are plural, plural R' s 1 The same or a different one of the above,
at R 2 Where there are plural, plural R' s 2 The same or different.
9. The method for manufacturing an organic semiconductor element according to claim 8, wherein a value represented by a+b in the formula (54) is 1 or more.
10. The method for manufacturing an organic semiconductor element according to any one of claims 1 to 9, wherein hansen solubility parameter δp of the first solvent component satisfies a relationship δp < 7.
11. The method for producing an organic semiconductor device according to any one of claims 1 to 10, wherein 2 minutes or more are required from the time when the second composition is applied to the first functional film until the solvent evaporates.
12. The method for manufacturing an organic semiconductor device according to any one of claims 1 to 11, wherein,
the second composition contains a second functional material different from the first functional material,
the second functional material comprises a low molecular aromatic compound having a molecular weight of less than 2000.
13. The method for manufacturing an organic semiconductor element according to any one of claims 1 to 12, wherein the first functional film is a hole transport layer and the second functional film is a light-emitting layer.
14. The method for manufacturing an organic semiconductor element according to any one of claims 1 to 13, wherein the heating in the step of providing the first functional film is performed at a temperature lower than a glass transition temperature of the aromatic amine polymer.
15. The method for producing an organic semiconductor element according to any one of claims 1 to 14, wherein a theoretical surface area, a volume, and a boiling point of the first solvent component calculated from a COSMO-RS solvation model and a viscosity at 23 ℃ satisfy the following relational expression (a):
32 Xviscosity-4.3 Xtheoretical surface area +5.4 Xvolume-boiling point >150 … (A),
the units of the theoretical surface area, the volume, the boiling point and the viscosity are respectivelyDEG C and mPa.s.
16. The method for manufacturing an organic semiconductor device according to any one of claims 1 to 15, wherein a total content of the first solvent components in the second composition is 15 mass% or more.
17. The method for manufacturing an organic semiconductor element according to any one of claims 1 to 16, wherein the first solvent component contains an aromatic hydrocarbon structure.
CN202280031351.1A 2021-04-28 2022-04-25 Method for manufacturing organic semiconductor element Pending CN117296451A (en)

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