WO2016021660A1

WO2016021660A1 - Copolymer, photoelectric conversion element, solar cell and solar cell module

Info

Publication number: WO2016021660A1
Application number: PCT/JP2015/072279
Authority: WO
Inventors: 理恵子藤田; 光教古屋; 和弘毛利; 賢一佐竹; 真紀大場; 潤也河井
Original assignee: 三菱化学株式会社
Priority date: 2014-08-06
Filing date: 2015-08-05
Publication date: 2016-02-11
Also published as: JPWO2016021660A1

Abstract

The present invention addresses the problem of providing a copolymer capable of improving exposure stability of a photoelectric conversion element, a photoelectric conversion element having high exposure stability, solar cell, and solar cell module. A copolymer comprises repeating units represented by formula (I) and repeating units represented by formula (II). (In formula (I), D is a donor monomer unit and A1 is an acceptor monomer unit. In formula (II), A2 is an acceptor monomer unit, L is a single bond or divalent linking group, and R¹ and R² are each independently a monovalent organic group.)

Description

Copolymer, photoelectric conversion element, solar cell, and solar cell module

The present invention relates to a copolymer, a photoelectric conversion element, a solar cell, and a solar cell module.

Π-conjugated polymers are used as semiconductor materials for organic electronic devices such as organic solar cells, organic EL elements, organic thin film transistors, and organic light emitting sensors. In particular, in an organic solar cell, it is desired to improve sunlight absorption efficiency, and it is important to develop a polymer that can absorb light having a long wavelength (600 nm or more). In order to achieve a longer absorption wavelength, an example in which a copolymer of a donor monomer and an acceptor monomer (hereinafter sometimes referred to as a copolymer) is used for a photoelectric conversion element has been reported.

Specifically, Non-Patent Document 1 describes a photoelectric conversion element using a copolymer having an imidothiophene unit and a dithienocyclopentadiene unit. Non-Patent Documents 1, 2, 3 and Patent Document 1 describe photoelectric conversion elements using a copolymer having an imidothiophene unit and a dithienosilole unit. Further, Non-Patent Document 2 describes a photoelectric conversion element using a copolymer having an imidothiophene unit and a dithienogermol unit. Patent Document 2 describes an example in which a photoelectric conversion element is manufactured using a copolymer having a donor unit, an acceptor unit, and a spacer unit.

International Publication No. 2012/102390 International Publication No. 2013/135339

Since organic thin-film solar cells are expected to be used in environments exposed to sunlight, not only conversion efficiency but also exposure stability is desired for practical use of organic thin-film solar cells. . However, according to the study by the present inventors, the organic thin-film solar cell using the copolymer described in Patent Document 1 and Non-Patent Documents 1 to 3 is irradiated with light at the manufacturing stage or when used. It has been found that there is a possibility that the conversion efficiency deteriorates as the time elapses. This is mainly because the copolymer of the material constituting the photoelectric conversion element of the organic thin film solar cell is deteriorated by light.
The present invention solves the above problems, and when used in a photoelectric conversion element, a copolymer that can improve the exposure stability of the photoelectric conversion element, and a photoelectric conversion element, a solar cell, and a solar cell module having high exposure stability. The issue is to provide.

As a result of intensive studies to solve the above problems, the inventors of the present application can solve the above problems by using a copolymer having a specific repeating unit in addition to a repeating unit of a donor monomer unit and an acceptor monomer unit. The present invention has been found and the present invention has been achieved. That is, the gist of the present invention is as follows.

[1] A copolymer having a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II).

(In Formula (I), D represents a donor monomer unit, A1 represents an acceptor monomer unit. In Formula (II), A2 represents an acceptor monomer unit, and L represents a direct bond or a divalent monomer unit. R ¹ and R ² each independently represent a monovalent organic group, and the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) are the same as each other. Not a repeating unit.)
[2] The copolymer according to [1], wherein D in the formula (I) is a structural unit represented by the following formula (III) or a structural unit represented by the following formula (XI): .

(In formula (III), Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent. X ¹ represents Q ¹ (R ³ ) (R ⁴ ) or Q ^3. represents (R ^10), Q ¹ represents an atom selected from the periodic table group 14 element, R ³ and R ⁴ are each independently, .Q ³ represents a hydrogen atom or a monovalent organic group, Represents an atom selected from Group 15 elements of the periodic table, and R ¹⁰ represents a hydrogen atom or a monovalent organic group, X ² represents a direct bond, an oxygen atom (O), a sulfur atom (S), N (R ⁵ ) or Q ² (R ⁶ ) (R ⁷ ), Q ² represents an atom selected from Group 14 elements of the periodic table, and R ⁵ to R ⁷ each represents a hydrogen atom or a monovalent organic group. To express.)

(In the formula (XI), Ar ³ and Ar ⁴ each independently represent an aromatic ring optionally having a substituent, and X ³ and X ⁴ each independently represent Q ⁴ (R ¹¹ ). Q ⁴ represents an atom selected from Group 14 elements of the periodic table, and R ¹¹ represents a hydrogen atom or a monovalent organic group.)
[3] In the formula (I) and the formula (II), A1 and A2 are each a structural unit represented by the following formula (XIV) or a structural unit represented by the following formula (XV). The copolymer according to [1] or [2].

(In the formula (XIV), Ar ⁵ is an aromatic hydrocarbon ring which may have a substituent, an aliphatic heterocyclic ring which may have a substituent, or an aromatic which may have a substituent. X ⁵ represents an atom selected from Group 16 elements of the periodic table.

(In the formula (XV), Ar ⁶ represents an aromatic hydrocarbon ring that may have a substituent, an aliphatic heterocyclic ring that may have a substituent, or an aromatic that may have a substituent. X ⁶ and X ⁷ each independently represent a nitrogen atom (N) or Q ⁵ (R ¹² ), Q ⁵ represents an atom selected from Group 14 elements of the Periodic Table, ¹² represents a hydrogen atom or a monovalent organic group.)
[4] The copolymer according to any one of [1] to [3], wherein A1 in the formula (I) and A2 in the formula (II) are the same.
[5] In the formula (II), L is a direct bond, a divalent monocyclic aromatic heterocyclic group which may have a substituent, and a substituent. Any one of [1] to [4], wherein the cyclic aromatic heterocyclic group is one selected from the group consisting of divalent polycyclic aromatic heterocyclic groups linked to each other The copolymer described.
[6] A photoelectric conversion element having at least a pair of electrodes and an active layer between the pair of electrodes on a substrate, wherein the active layer is any one of [1] to [5] A photoelectric conversion element comprising a copolymer.
[7] A solar cell having the photoelectric conversion element according to [6].
[8] A solar cell module having the solar cell according to [7].

ADVANTAGE OF THE INVENTION According to this invention, when used for a photoelectric conversion element, the copolymer which can improve the exposure stability of a photoelectric conversion element, and the photoelectric conversion element, solar cell, and solar cell module provided with high exposure stability are provided. Can do.

FIG. 1 is a cross-sectional view schematically showing a configuration of a photoelectric conversion element as one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a configuration of a solar cell as one embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the configuration of the solar cell module as one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not specified in these contents unless it exceeds the gist.

<1. Copolymer according to the present invention>
The copolymer according to the present invention has a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II). The repeating unit represented by the following formula (I) and the repeating unit represented by the following formula (II) are not the same repeating unit. In the present invention, the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) are not the same repeating unit. It means that the repeating unit represented by II) is not the same structural unit. That is, even when the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) differ only in substituents, the repeating unit represented by the formula (I) and the formula (II) are also represented. The repeating unit is different from the repeating unit.

In formula (I), D represents a donor monomer unit, and A1 represents an acceptor monomer unit. In the present invention, the donor monomer unit means a monomer unit having a small ionization potential and a strong tendency to donate electrons. The acceptor monomer unit means a monomer unit having a large electron affinity and a strong tendency to accept electrons. Specifically, the donor monomer unit (D) is a monomer unit having a smaller ionization potential and electron affinity than the acceptor monomer unit (A1), and the acceptor monomer unit (A1) is more than the donor monomer unit (D). Is a monomer unit having a large ionization potential and electron affinity. That is, in the present invention, the donor monomer unit (D) has a HOMO energy level higher than that of the acceptor monomer unit (A1) and is higher than the LUMO energy level of the acceptor monomer unit. A structural unit having a LUMO energy level. HOMO energy level and LUMO energy level can be estimated experimentally by photoelectron yield spectroscopy (PYS) measurement, ultraviolet photoelectron spectroscopy (UPS) measurement, inverse photoelectron spectroscopy (IPES) measurement, cyclic voltammetry measurement, etc. It can be calculated by quantum chemical calculation such as orbital method (MO method) and density half function method (DFT method). In addition, when calculating the HOMO energy level and the LUMO energy level of the donor monomer unit (D) and the acceptor monomer unit (A1), the calculation is performed by substituting each terminal portion with a hydrogen atom.

The donor monomer unit (D) is not particularly limited as long as it has the above-described characteristics, and examples thereof include a divalent aromatic group which may have a substituent. Examples of the divalent aromatic group include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group.

The divalent aromatic hydrocarbon group is not particularly limited, and examples thereof include a divalent condensed polycyclic aromatic hydrocarbon group. For example, a divalent organic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon compound such as naphthalene, fluorene, anthracene, phenanthrene, perylene, or pyrene can be given.

The divalent aromatic heterocyclic group is not particularly limited, and is a divalent monocyclic aromatic heterocyclic group, a divalent condensed polycyclic aromatic heterocyclic group, or a divalent monocyclic. And a divalent polycyclic aromatic heterocyclic group in which a divalent condensed polycyclic aromatic heterocyclic group is linked. These groups are not particularly limited, for example, thiophene, bithiophene, terthiophene, quarterthiophene, thienothiophene, dithienothiophene, benzodithiophene, cyclopentadithiophene, dithienosilole, dithienogermole, indasenodithiophene , Divalent organic groups obtained by removing two hydrogen atoms from an aromatic heterocyclic compound such as dithienopyrrole, carbazole, arylamine, and isothianaphthene. Further, donor monomer units described in non-patent literature (Macromolecules 2012, 45, 607-632) can be mentioned.

The divalent aromatic hydrocarbon group and aromatic heterocyclic group constituting the donor monomer unit (D) may have a substituent as described above. The substituent is not particularly limited, and examples thereof include a monovalent organic group. Specifically, aliphatic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group, aromatic heterocyclic group, alkoxy group, aryloxy group, amino group, amide group, alkoxycarbonyl group, aryloxycarbonyl group , An alkylcarbonyl group, an arylcarbonyl group, an alkylthio group, an arylthio group, or a halogen atom. In addition, the number of the substituents is not particularly limited, and may have a plurality of substituents as long as substitution is possible. Moreover, you may have 2 or more types of substituents.

Among them, the donor monomer unit (D) is easily expressed on the same plane and is easily expressed by the structural unit represented by the following formula (III) or the following formula (XI) from the viewpoint of easily increasing the wavelength by π conjugation. It is preferable that it is a structural unit.

In formula (III), Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent. Examples of the aromatic ring which may have a substituent include an aromatic hydrocarbon ring which may have a substituent or an aromatic heterocyclic ring which may have a substituent. Ar ¹ and Ar ² form a condensed ring with the ring containing X ¹ and X ² .

The aromatic hydrocarbon ring of the aromatic hydrocarbon ring which may have a substituent is not particularly limited, but is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, monocyclic aromatic hydrocarbon rings such as benzene rings; condensed polycyclic rings such as naphthalene rings, indane rings, indene rings, phenanthrene rings, fluorene rings, anthracene rings, azulene rings, pyrene rings, and perylene rings An aromatic hydrocarbon ring of the formula Of these, a benzene ring or a naphthalene ring is preferable.

The aromatic heterocyclic ring that may have a substituent is not particularly limited, but is preferably an aromatic heterocyclic ring having 2 to 30 carbon atoms. Specifically, monocyclic aromatic heterocycles such as thiophene ring, furan ring, pyridine ring, pyrimidine ring, thiazole ring, oxazole ring, triazole ring; or thienothiophene ring, benzothiophene ring, benzofuran ring, benzothiazole Examples thereof include condensed polycyclic aromatic heterocycles such as a ring, a benzoxazole ring, a benzotriazole ring, and a thiadiazolopyridine ring. Among these, a thiophene ring, a pyridine ring, a pyrimidine ring, a thiazole ring, a thiadiazole ring, an oxazole ring, an oxadiazole ring, or a triazole ring is preferable.

The substituent that the aromatic hydrocarbon ring and aromatic heterocyclic ring that are aromatic rings may have is not particularly limited. For example, as described above, the divalent monomer unit (D1) constituting the donor monomer unit (D1) is not limited. The substituent which the aromatic hydrocarbon group and the bivalent aromatic heterocyclic group may have is mentioned, and may have a plurality of substituents within a substitutable range. The aromatic ring may have two or more kinds of substituents.

Among the above, Ar ¹ and Ar ² are each independently an optionally substituted aromatic hydrocarbon ring having 2 to 6 carbon atoms, or an optionally substituted carbon. An aromatic heterocycle having 2 to 6 carbon atoms is more preferable, and an aromatic heterocycle having 2 to 6 carbon atoms which may have a substituent is particularly preferable. Specific examples include a furan ring which may have a substituent or a thiophene ring which may have a substituent, and a thiophene ring which may have a substituent is particularly preferable.

In formula (III), X ¹ represents Q ¹ (R ³ ) (R ⁴ ) or Q ³ (R ¹⁰ ). Q ¹ represents an atom selected from Group 14 elements of the periodic table, preferably a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge). Q ³ represents an atom selected from Group 15 elements of the periodic table, preferably nitrogen atom (N) or phosphorus atom (P).

R ³ and R ⁴ each represent a group bonded to Q ¹ , and each independently represents a hydrogen atom or a monovalent organic group. R ³ and R ⁴ may be the same group or different from each other. R ¹⁰ represents a group bonded to Q ³ and represents a hydrogen atom or a monovalent organic group.

The monovalent organic group is not particularly limited, but may have an aliphatic hydrocarbon group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, or a substituent. An aliphatic heterocyclic group which may have a substituent, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a substituent An amino group which may have a substituent, an amide group which may have a substituent, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, a substituent An alkylcarbonyl group which may have a group, an arylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, or A halogen atom is mentioned.

Examples of the aliphatic hydrocarbon group include a linear aliphatic hydrocarbon group, a branched aliphatic hydrocarbon group, and a cyclic aliphatic hydrocarbon group. The aliphatic hydrocarbon group has 1 or more carbon atoms, preferably 3 or more, more preferably 4 or more, and preferably 30 or less, and 20 or less. More preferably, it is more preferably 16 or less, and particularly preferably 12 or less. In the case of a branched aliphatic hydrocarbon group, the range of the carbon number is the number of carbons forming the longest straight chain.

Examples of the linear aliphatic hydrocarbon group include a linear alkyl group, a linear alkenyl group, and a linear alkynyl group.

The linear alkyl group is not particularly limited, and examples thereof include n-butyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, and n-dodecyl group.

The linear alkenyl group is not particularly limited, and examples thereof include a 5-hexenyl group, a 7-octenyl group, an 11-dodecenyl group, and a 12-tridecenyl group.

The linear alkynyl group is not particularly limited, and examples thereof include a 5-hexynyl group, a 7-octynyl group, a 9-decynyl group, and an 11-dodecynyl group.

Examples of the branched aliphatic hydrocarbon group include a branched alkyl group, a branched alkenyl group, and a branched alkynyl group.

Examples of the branched alkyl group include a branched primary alkyl group, a branched secondary alkyl group, and a branched tertiary alkyl group. The branched primary alkyl group means a branched alkyl group having two hydrogen atoms bonded to a carbon atom having a free valence. The branched secondary alkyl group means a branched alkyl group having one hydrogen atom bonded to a carbon atom having a free valence. The branched tertiary alkyl group means a branched alkyl group having no hydrogen atom bonded to a carbon atom having a free valence. Here, the free valence refers to a substance that can form a bond with another free valence as described in the organic chemistry / biochemical nomenclature (above) (Revised 2nd edition, Nankodo, 1992).

The branched primary alkyl group is not particularly limited, and examples thereof include 2-ethylhexyl group, 2-butyloctyl group, 3,7-dimethyloctyl group, 2-hexyldecyl group, and 2-decyltetradecyl group. It is done.

The branched secondary alkyl group is not particularly limited, and examples thereof include isopropyl group, 3-ethyl-1,5-dimethylnonyl group, and 1-propylheptyl group.

The branched tertiary alkyl group is not particularly limited, and examples thereof include a t-butyl group, a 1-butyl-1-ethylpentyl group, a 1-butyl-1-methylpentyl group, and a 1-ethyl-1-methylhexyl group. 1-methyl-1-propylpentyl group, 1-ethyl-1-methylpropyl group or 1,1,2,2-tetramethylpropyl group.

The branched alkenyl group is not particularly limited, and examples thereof include a 2-methyl-2-propenyl group, a 3-methyl-3-butenyl group, and a 4-methyl-2-hexenyl group.

The branched alkynyl group is not particularly limited, and examples thereof include 1-methyl-2-propenyl group, 2-methyl-3-butenyl group, 4-methyl-2-hexenyl group and the like.

The aromatic hydrocarbon group is not particularly limited, and examples thereof include a monocyclic aromatic hydrocarbon group, a polycyclic aromatic hydrocarbon group, and a condensed polycyclic aromatic hydrocarbon group. The aromatic hydrocarbon group has preferably 6 or more carbon atoms, on the other hand, preferably 30 or less, more preferably 20 or less, and particularly preferably 14 or less. Specific examples include a phenyl group, a naphthyl group, an indanyl group, an indenyl group, a fluorenyl group, an anthracenyl group, and an azulenyl group. Of these, a phenyl group is preferred.

The aliphatic heterocyclic group is not particularly limited, but the aliphatic heterocyclic group preferably has 2 or more carbon atoms, on the other hand, preferably 30 or less, more preferably 14 or less. Preferably, it is 10 or less, more preferably 6 or less. Specific examples include an oxetanyl group, a pyrrolidinyl group, a tetrahydrofuryl group, a tetrahydrothienyl group, a piperidinyl group, a tetrahydropyranyl group, and a tetrahydrothiopyranyl group.

The aromatic heterocyclic group is not particularly limited, and examples thereof include a monocyclic aromatic heterocyclic group, a polycyclic aromatic heterocyclic group, and a condensed polycyclic aromatic heterocyclic group. The number of carbon atoms contained in the aromatic heterocyclic group is preferably 2 or more, on the other hand, preferably 30 or less, more preferably 20 or less, and particularly preferably 14 or less. Specifically, thienyl, furanyl, pyridyl, pyrrolyl, imidazolyl, pyrimidyl, thiazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyrazolyl, triazolyl, benzothiophenyl, benzofuranyl, benzothiazolyl Group, benzoxazolyl group or benzotriazolyl group. Among these, a thienyl group, a pyridyl group, a pyrimidyl group, a thiazolyl group, or an oxazolyl group can be given.

The alkoxy group is not particularly limited, but the alkoxy group has 1 or more carbon atoms, preferably 3 or more, more preferably 5 or more, and preferably 30 or less. It is more preferably 20 or less, and particularly preferably 14 or less. Specific examples include a hexyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a dodecyloxy group, and a tetradecyloxy group.

In addition, the above-mentioned aliphatic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group and aromatic heterocyclic group, alkoxy group, aryloxy group, amino group, amide group, alkoxycarbonyl group, aryloxycarbonyl group The substituent that the alkylcarbonyl group, arylcarbonyl group, alkylthio group, and arylthio group may have is not particularly limited. For example, aliphatic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group, or aromatic heterocyclic group, alkoxy group, aryloxy group, amino group, amide group, alkoxycarbonyl group, aryloxycarbonyl group, alkyl Examples include a carbonyl group, an arylcarbonyl group, an alkylthio group, an arylthio group, or a halogen atom. Moreover, you may have 2 or more types of substituents. Furthermore, these substituents may further have another substituent.

Among the above, R ³ and R ⁴ are each independently a linear aliphatic hydrocarbon group having 4 to 12 carbon atoms or a branched aliphatic hydrocarbon group having 4 to 12 carbon atoms. It is preferable that In particular, a linear alkyl group having 4 to 12 carbon atoms or a branched alkyl group having 4 to 12 carbon atoms is preferable. For example, n-octyl group, 2-ethylhexyl group and the like can be mentioned. In the case of a branched aliphatic hydrocarbon group, the range of the carbon number is the number of carbons forming the longest straight chain.

In the above formula (III), X ² represents a direct bond, an oxygen atom (O), a sulfur atom (S), N (R ⁵ ), or Q ² (R ⁶ ) (R ⁷ ). Q ² represents an atom selected from Group 14 elements of the periodic table, and examples thereof include a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge), which is a silicon atom (Si). It is particularly preferred.

R ⁵ represents a group bonded to the nitrogen atom (N), and R ⁶ and R ⁷ each represents a group bonded to Q ² . R ⁵ to R ⁷ are each a hydrogen atom or a monovalent organic group, and specific examples thereof include the groups described for R ³ and R ⁴ , and preferred groups are also the same.

Among these, X ² is preferably a direct bond, an oxygen atom (O), a sulfur atom (S), or Q ² (R ⁶ ) (R ⁷ ). In addition, in order to obtain good carrier transfer between molecules without excessively increasing the steric hindrance on Ar ¹ and Ar ² , X ² is more preferably a direct bond, an oxygen atom (O) or a sulfur atom (S) Particularly preferred is a direct bond.

Although not necessarily limited, examples of the structural unit represented by the above formula (III) include the following structural units.

Among the structural units represented by the formula (III), the donor monomer unit (D) is a structural unit represented by the following formula (XII) in which both Ar ¹ and Ar ² are thiophene rings. preferable.

In the formula (XII), X ¹ and X ² are synonymous with X ¹ and X ² of In the formula (III), the same is true preferred group.

In the above formula (XI), X ³ and X ⁴ each independently represent Q ⁴ (R ¹¹ ). Q ⁴ represents an atom selected from Group 14 elements of the periodic table, and specifically includes a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge). Among them, a carbon atom (C) It is preferable that R ¹¹ represents a group bonded to Q ⁴ and represents a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but has an aliphatic hydrocarbon group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, and a substituent. An aliphatic heterocyclic group that may be substituted, an aromatic heterocyclic group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, An amino group which may have a substituent, an amide group which may have a substituent, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent An optionally substituted alkylcarbonyl group, an optionally substituted arylcarbonyl group, an optionally substituted alkylthio group, and an optionally substituted arylthio group Or a halogen atom. These groups are not particularly limited, but specific examples include the groups mentioned for R ³ above, and the preferred groups are also the same. X ³ and X ⁴ may be the same group or different groups.

In formula (XI), Ar ³ and Ar ⁴ each independently represent an aromatic ring which may have a substituent, and Ar ³ and Ar ⁴ are a ring containing X ³ and X ⁴ and a condensed ring Form. Examples of the aromatic ring which may have a substituent include an aromatic hydrocarbon ring which may have a substituent or an aromatic heterocyclic ring which may have a substituent. The aromatic hydrocarbon ring which may have a substituent and the aromatic heterocyclic ring which may have a substituent are not particularly limited, but Ar ¹ and Ar ² in the formula (III) The aromatic hydrocarbon ring which may have the substituent mentioned and the aromatic heterocyclic ring which may have a substituent are mentioned.

Although not limited, specific examples of the structural unit represented by the formula (XI) include the following structural units.

Among the structural units represented by the formula (XI), Ar ³ and Ar ⁴ are both preferably structural units represented by the following formula (XIII), which are thiophene rings.

In the formula (XIII), respectively X ³ and X ⁴ has the same meaning as X ³ and X ⁴ in the formula (XI), it is also preferred group.

Among these, the donor monomer unit is represented by the following formula (IV) in which X ¹ is Q ¹ (R ³ ) (R ⁴ ) and X ² is a direct bond in the above formula (XII). It is preferably a structural unit.

The reason why the donor monomer unit (D) is preferably a repeating unit represented by the above formula (IV) includes the following reasons. When a copolymer having the repeating unit represented by the above formula (IV) as a main component is used for a photoelectric conversion element, high conversion efficiency can be expected, but the photoelectric conversion element using the copolymer was exposed. In some cases, conversion efficiency may be significantly reduced. On the other hand, as will be described later, the copolymer mainly composed of the repeating unit represented by the above formula (II) tends not to have high conversion efficiency, but the copolymers form a good π stack and have high exposure stability. Tend. Therefore, in addition to the repeating unit represented by the above formula (I), the copolymer having the repeating unit represented by the above formula (II) is used for a photoelectric conversion element, thereby having high conversion efficiency and high exposure stability. A photoelectric conversion element can be provided.

Wherein (IV), Q ¹ has the same meaning as to Q ¹ in formula (III). Among these, Q ¹ is preferably a silicon atom (Si).

In formula (IV), R ³ and R ⁴ have the same meanings as R ³ and R ⁴ mentioned in the description of formula (III), respectively. Among them, R ³ and R ⁴ are each a linear aliphatic hydrocarbon group that may have a substituent or a branched aliphatic hydrocarbon group that may have a substituent. Is preferred.

In the above formula (I), A1 represents an acceptor monomer unit as described above. The acceptor monomer unit is not particularly limited as long as it has an acceptor property, and examples thereof include a divalent aromatic group which may have a substituent. Examples of the divalent aromatic group include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. Examples include benzothiadiazole, naphthobisiathiazole, diketopyrrolopyrrole, thienothiophene, thiazole, thiadiazole, oxazole, oxadiazole, pyridine, pyrimidine, quinoxaline, thienopyrazine, imidothiophene, and fluorobenzene. Further, acceptor monomer units described in non-patent literature (Macromolecules 2012, 45, 607-632) can be mentioned. As described above, the divalent aromatic hydrocarbon group and divalent aromatic heterocyclic group constituting these acceptor monomer units may have a substituent. The substituent that the acceptor monomer unit may have is not particularly limited, and examples thereof include the substituent that the donor monomer unit described above may have.

Among these, the acceptor monomer unit is preferably a structural unit represented by the following formula (XIV) or a structural unit represented by the following formula (XV).

In the above formula (XIV), Ar ⁵ is an aromatic hydrocarbon ring that may have a substituent, an aliphatic heterocyclic ring that may have a substituent, or an aromatic that may have a substituent. Group heterocycles. The aromatic hydrocarbon ring which may have a substituent or the aromatic hydrocarbon ring which may have a substituent is the aromatic heterocycle of the aromatic heterocycle which may have a substituent, Ar in the above formula (III) ^The aromatic hydrocarbon ring and aromatic heterocyclic ring mentioned in 1 are mentioned. Among these, a thiophene ring, a pyridine ring, a pyrimidine ring, a thiazole ring, a thiadiazole ring, an oxazole ring, an oxadiazole ring, or a triazole ring is preferable. Examples of the aliphatic heterocyclic ring include a pyrrolidine ring and a piperidine ring, and among them, a pyrrolidine ring is preferable.

In the above formula (XIV), X ⁵ represents an atom selected from Group 16 elements of the periodic table. Specifically, an oxygen atom (O), a sulfur atom (S), a selenium atom (Se) or a tellurium atom ( Te). Of these, X ⁵ is preferably a sulfur atom.

Although not necessarily limited, the following are mentioned as specific examples of the structural unit represented by the above formula (XIV).

In the above formula (XV), Ar ⁶ represents an aromatic hydrocarbon ring that may have a substituent, an aliphatic heterocyclic ring that may have a substituent, or an aromatic that may have a substituent. Represents a family heterocycle. The aromatic hydrocarbon ring optionally having a substituent, the aliphatic heterocyclic ring optionally having a substituent or the aromatic heterocyclic ring optionally having a substituent is not particularly limited, For example, the aromatic hydrocarbon ring which may have a substituent mentioned for Ar ⁵ in the above formula (XIV), an aliphatic heterocyclic ring which may have a substituent, or a substituent Aromatic heterocycles may be mentioned.

In the formula (XV), X ⁶ and X ⁷ each independently represent a nitrogen atom (N) or Q ⁵ (R ¹² ). Q ⁵ represents an atom selected from Group 14 elements of the periodic table, and specifically includes a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge), and among them, a carbon atom (C) It is preferable that R ¹² represents a group bonded to Q ⁵ and represents a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, and examples thereof include the groups described above for R ³ .

Although not limited, the following are mentioned as specific examples of the structural unit represented by the above formula (XV).

Among these, the acceptor monomer unit (A1) is preferably a structural unit represented by the following formula (V).

Wherein (V), X ⁵ has the same meaning as X ⁵ in the formula (XIV), represents an atom selected from periodic table Group 16 element, specifically, an oxygen atom (O), sulfur atom (S) represents a selenium (Se) atom or a tellurium atom (Te). Among these, from the viewpoint of ease of synthesis, X ⁵ is preferably an oxygen atom (O) or a sulfur atom (S), and particularly preferably a sulfur atom (S).

In formula (V), R ⁸ may be a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but may have an aliphatic hydrocarbon group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, or a substituent. An aliphatic heterocyclic group which may have a substituent, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a substituent An amino group which may have a substituent, an amide group which may have a substituent, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, a substituent An alkylcarbonyl group which may have a group, an arylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, or A halogen atom is mentioned. Specific groups of these groups are not particularly limited, and examples thereof include the same groups as those described above for R ³ and R ⁴ . Moreover, the substituent which these groups may have includes the same substituents as the substituents mentioned in the above R ³ and R ⁴ .

Among these, R ⁸ is preferably a linear aliphatic hydrocarbon group which may have a substituent or an aromatic hydrocarbon group which may have a substituent. When R ⁸ is an aromatic hydrocarbon group, the aromatic hydrocarbon group preferably has an alkoxy group or an aliphatic hydrocarbon group as a substituent in order to improve solubility and conversion efficiency.

In addition, the preferable form of the repeating unit represented by the formula (I) of the copolymer according to the present invention is a structural unit in which the donor monomer unit (D) is represented by the above formula (III) or the above formula (IV). Yes, the acceptor monomer unit (A1) is a repeating unit which is a structural unit represented by the above formula (XIV). Among them, it is preferable that the donor monomer unit (D) is a repeating unit represented by the above formula (IV) or the acceptor monomer unit (A1) is a repeating unit represented by the above formula (V). More preferably, the donor monomer unit (D) is a monomer unit represented by the above formula (IV) and the acceptor monomer unit (A1) is a repeating unit which is a monomer unit represented by the above formula (V). .

Hereinafter, specific examples of the repeating unit represented by the formula (I) of the copolymer according to the present invention will be exemplified. However, in the present invention, the repeating unit represented by the formula (I) is not limited to the following.

As described above, the copolymer according to the present invention has a repeating unit represented by the following formula (II).

In formula (II), L includes a direct bond or a divalent linking group. There are no particular restrictions on the divalent linking group, but it is likely to be coplanar with the thiophene rings on both sides, so that it has 2 or more and 8 or less carbon atoms such as a vinylene group or an alkenylene group or an ethynylene group or more. Examples thereof include an alkynylene group of 8 or less, a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent.

The divalent aromatic hydrocarbon group which may have a substituent and the divalent aromatic heterocyclic group which may have a substituent are monocyclic, polycyclic, or condensed polycyclic Any of these may be used.

Among them, since adjacent rings are more likely to be coplanar, intramolecular carrier movement is improved, and also advantageous for π stack between molecules and for intermolecular carrier movement. A direct bond, a divalent monocyclic aromatic heterocyclic group which may have a substituent, or a monocyclic aromatic heterocyclic group which may have a substituent It is preferably a cyclic aromatic heterocyclic group, specifically, a thienylene group which may have a substituent, a bithienylene group which may have a substituent, or a substituent. An optional tertienylene group may be mentioned. Among these, as the number of rings to be connected increases, the degree of freedom of rotation between adjacent rings increases, so that L as a whole is less likely to be coplanar. Therefore, L has a direct bond and a substituent. It is preferably a thienylene group which may have a substituent or a bithienylene group which may have a substituent, more preferably a thienylene group which may have a direct bond or a substituent, and a direct bond. Particularly preferred.

The substituent that the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group may have is not particularly limited, and examples thereof include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aromatic group. An aromatic group, an alkoxy group, or a halogen atom can be mentioned, and it is preferably unsubstituted in order to reduce steric hindrance.

In formula (II), R ¹ and R ² each independently represents a monovalent organic group. The monovalent organic group is not particularly limited, but has an aliphatic hydrocarbon group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, and a substituent. An aliphatic heterocyclic group which may be substituted, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a substituent An amino group which may have a group, an amide group which may have a substituent, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, An alkylcarbonyl group which may have a substituent, an arylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, and an arylthio group which may have a substituent; Can be mentioned. R ¹ and R ² may be the same group or different groups. These groups are not particularly limited, and specific examples thereof include the same groups as those described for R ³ and R ⁴ in formula (III). Among them, both R ¹ and R ² may have an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. An aliphatic heterocyclic group, an aromatic heterocyclic group which may have a substituent, and an alkoxy group which may have a substituent are preferable, and among them, an aliphatic which may have a substituent An aromatic hydrocarbon group optionally having a substituent, an aliphatic heterocyclic group optionally having a substituent, and an aromatic heterocyclic group optionally having a substituent. More preferably it is.

When R ¹ and R ² have the above-described group, the solubility of the copolymer having the structural unit in the solvent is improved as compared with the case where R ¹ and R ² are hydrogen atoms, An improvement in properties can be expected, and uniform film formation becomes possible. In addition, since the copolymer having the structural unit at the time of film formation is easily oriented in a certain direction, it contributes to a longer wavelength, and carrier movement proceeds smoothly, so that improvement in conversion efficiency can be expected. In addition, it is extremely important that the above-mentioned groups are arranged at the positions of R ¹ and R ^{2 in} the formula (II). That is, when the group as described above is arranged at a place other than where R ¹ and R ² in the formula (II) are arranged, steric hindrance occurs between the group and the other group. It becomes easy. If steric hindrance occurs, the copolymers cannot be arranged in a certain direction, resulting in an unstable structure, and it is considered that the exposure stability is lowered. Therefore, in the formula (II), the above groups are arranged at the positions of R ¹ and R ² where steric hindrance is unlikely to occur, so that the copolymers are easily oriented in a certain direction without steric hindrance. Therefore, it is considered that the exposure stability is improved.

The thiophene ring-L-thiophene ring in formula (II) is preferably a donor component. Since the thiophene ring-L-thiophene ring in the formula (II) is a donor component, hole transport through the π stack formed by L and the thiophene rings on both sides of the thiophene ring smoothly proceeds, thereby providing photoelectric conversion characteristics. Is considered to increase. Further, the thiophene ring-L-thiophene ring in the formula (II) is considered to be a donor component, so that intramolecular charge transfer with the A2 component is likely to occur, so that the absorption wavelength tends to be long. .

R ¹ and R ² are preferably each independently an aliphatic hydrocarbon group or an alkoxy group in order to further suppress steric hindrance among the groups described above, and when used as an organic thin film solar cell. An aliphatic hydrocarbon group is particularly preferable because the open circuit voltage tends to increase.

In order to suppress steric hindrance and improve the conversion efficiency, R ¹ and R ² are preferably aliphatic hydrocarbon groups having 3 to 16 carbon atoms, and in particular, having 6 to 14 carbon atoms. It is preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group is particularly preferably an alkyl group. In this case, an alkyl group having 3 to 16 carbon atoms is preferable, and an alkyl group having 6 to 14 carbon atoms is particularly preferable. Specific examples include an n-octyl group, an n-decyl group, and an n-dodecyl group.

In formula (II), A2 represents an acceptor monomer unit in the same manner as A1. When A2 is an acceptor component, it is considered that the absorption wavelength becomes longer because intramolecular charge transfer easily occurs between the thiophene ring and the L-thiophene ring that functions as a donor component. A2 is not particularly limited, but is preferably a structural unit represented by the above formula (XIV) or a structural unit represented by the above formula (XV) mentioned in the acceptor monomer unit (A1), and is preferably a repeating unit. The unit is the same.

Note that A1 and A2 may be the same acceptor monomer units or different acceptor monomer units. However, it is preferable that the main skeleton of A1 and the main skeleton of A2 are the same in order to easily develop high photoelectric conversion characteristics because carrier movement occurs smoothly without generating intramolecular carrier traps, and A1 and It is particularly preferred that A2 is the same. The main skeleton of A1 and the main skeleton of A2 are the same as long as the main skeleton of A1 and the main skeleton of A2 are the same, the substituents of the main skeleton of A1 and the main skeleton of A have It means that the substituents may be different. On the other hand, A1 and A2 being the same means that A1 and A2 including the substituent are the same structural unit. From the above viewpoint, when A1 is a repeating unit represented by the above formula (V), A2 is preferably a structural unit represented by the following formula (VI).

In the formula (VI), X ⁸ represents an atom selected from Group 16 elements of the periodic table, specifically, an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), or tellurium (Te ) Atoms. Among them, an oxygen atom or a sulfur atom is preferable, and a sulfur atom is particularly preferable.

In formula (VI), R ⁹ represents a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but may have an aliphatic hydrocarbon group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, or a substituent. And an aliphatic heterocyclic group which may be substituted or an aromatic heterocyclic group which may have a substituent. Incidentally, aliphatic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group, an aromatic heterocyclic group is not particular limitation, include the same groups as R ^8, a preferred group in R ⁸ Examples thereof include the same groups as those mentioned above. R ⁹ in the formula (VI) may be the same as or different from R ⁸ in the formula (V), but R ⁸ and R ⁹ are preferably the same group.

Hereinafter, preferred modes of the repeating unit represented by the formula (II) of the copolymer according to the present invention will be exemplified. However, the repeating unit represented by the formula (II) is not limited to the following.

In the copolymer according to the present invention, the repeating unit represented by the above formula (I) and the repeating unit represented by the above formula (II) can be arbitrarily selected, but the above formula (I) and the above formula (II) ), The donor monomer unit (D) is a structural unit represented by the above formula (III) or a structural unit represented by the above formula (XI), and the acceptor monomer units (A1) and (A2) are The structural unit represented by the above formula (XIV) is preferable. Further, in the above formulas (I) and (II), the donor monomer unit (D) is a structural unit represented by the above formula (XII) or a structural unit represented by the above formula (XIII), and an acceptor The monomeric units (A1) and (A2) are preferably structural units represented by the above formula (XIV). In addition, the donor monomer unit (D) in the above formula (I) and the above formula (II) is a structural unit represented by the above formula (IV), and the acceptor monomer unit (A1) is the above formula (V). It is preferable that the acceptor monomer unit (A2) is a copolymer represented by the above formula (VI).

In the copolymer according to the present invention, the arrangement state of the repeating unit represented by the above formula (I) and the repeating unit represented by the above formula (II) may be any of alternating, block or random. That is, the copolymer according to the present invention may be an alternating copolymer, a block copolymer, or a random copolymer. In addition, a copolymer having an intermediate structure among these copolymers, for example, a random copolymer having a block property may be used. Further, it may be a copolymer having a branch in the main chain and having 3 or more terminal portions, and a dendrimer. Among these, a block copolymer or a random copolymer is preferable because it is easy to synthesize and regularity can be lowered, and the solubility of the copolymer is improved and the storage stability of the ink in which the copolymer is dissolved is improved. In view of this, a random copolymer is more preferable.

The terminal portion of the polymer having the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) is not particularly limited, but an aromatic hydrocarbon ring, an aromatic heterocyclic ring, or It is preferably end-gapped with hydrogen atoms.

Further, in the copolymer having the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II), the ratio of each repeating unit is not particularly limited, but the repeating unit represented by the formula (I) The ratio of the repeating unit represented by the formula (II) to the unit is such that the units represented by the above formula (II) are sufficiently π stacked so that many intermolecular carrier paths are formed and light is irradiated. Even when a part is damaged, the decrease in photoelectric conversion efficiency is suppressed, so that it is preferably 0.1 or more, more preferably 0.3 or more, and particularly preferably 0.4 or more. preferable. On the other hand, the ratio of the repeating unit represented by the formula (II) to the repeating unit represented by the formula (I) increases the contribution of the π stack and increases the solubility as the unit represented by the formula (II) increases. In order to be considered to become low, it is preferably 10 or less, more preferably 8 or less, and particularly preferably 3 or less.

The copolymer according to the present invention may contain a repeating unit other than the repeating unit represented by the above formula (I) and the repeating unit represented by the above formula (II) as long as the effects of the present invention are not impaired. Good. Although the repeating unit which may be specifically contained is not particularly limited, the donor monomer unit and the acceptor monomer mentioned in D and A1 in the above formula (I) and A2 in the formula (II) And repeating units composed of units.

In the copolymer according to the present invention, the ratio of the repeating unit represented by the above formula (I) and the total number represented by the above formula (II) is not particularly limited, but the repeating unit represented by the above formula (I) and the above The copolymer according to the present invention has a copolymer in which the total of the repeating units represented by the formula (II) has a repeating unit represented by the above formula (I) and a repeating unit represented by the above formula (II). The ratio of the repeating unit to the repeating unit is preferably 0.1 or more, more preferably 0.3 or more, and particularly preferably 0.5 or more in order to obtain good semiconductor characteristics. On the other hand, the upper limit is 1 or less.

The polystyrene-reduced weight average molecular weight (Mw) of the copolymer according to the present invention is not particularly limited, but is usually 5.0 × 10 ³ or more, preferably 1.0 × 10 ⁴ or more, more preferably 1.5 ×. 10 ⁴ or more, more preferably 2.0 × 10 ⁴ or more, still more preferably 3.0 × 10 ⁴ or more, particularly preferably 3.5 × 10 ⁴ or more, and most preferably 4.0 × 10 ⁴ or more. . On the other hand, it is preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, and particularly preferably 5.0 × 10 ⁵ or less. The weight average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

The polystyrene-reduced number average molecular weight (Mn) of the copolymer according to the present invention is not particularly limited, but is usually 3.0 × 10 ³ or more, preferably 5.0 × 10 ³ or more, more preferably 8.0 ×. 10 ³ or more, more preferably 1.0 × 10 ⁴ or more, and particularly preferably 2.0 × 10 ⁴ or more. On the other hand, preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, further preferably 5.0 × 10 ⁵ or less, even more preferably 2.0 × 10 ⁵ or less, and particularly preferably 1 0.0 × 10 ⁵ or less. The number average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

The molecular weight distribution (PDI, (weight average molecular weight / number average molecular weight (Mw / Mn))) of the copolymer according to the present invention is usually 1.0 or more, preferably 1.1 or more, more preferably 1.2 or more, Preferably it is 1.3 or more. On the other hand, it is usually 50.0 or less, preferably 20.0 or less, more preferably 15.0 or less, and still more preferably 10.0 or less. The molecular weight distribution is preferably in this range in that the solubility of the copolymer can be in a range suitable for coating.

The polystyrene equivalent weight average molecular weight, number average molecular weight, and molecular weight distribution of the copolymer according to the present invention can be determined by gel permeation chromatography (GPC). Specifically, two Polymer Laboratories GPC columns (PLgel MIXED-B 10 μm, inner diameter 7.5 mm, length 30 cm) are connected in series as a column, and LC-10AT (manufactured by Shimadzu Corporation) as a pump, as an oven It can be measured by using CTO-10A (manufactured by Shimadzu Corporation), a differential refractive index detector (manufactured by Shimadzu Corporation: RID-10A), and a UV-vis detector (manufactured by Shimadzu Corporation: SPD-10A). As a measuring method, a copolymer (1 mg) to be measured is dissolved in chloroform (200 mg), and 1 μL of the obtained solution is injected into a column. Measurement is performed at a flow rate of 1.0 mL / min at 80 ° C. using orthodichlorobenzene as the mobile phase. LC-Solution (manufactured by Shimadzu Corporation) is used for the analysis.

The solubility of the copolymer according to the present invention is not particularly limited, but preferably the solubility in chlorobenzene at 25 ° C. is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more. On the other hand, it is usually 30% by mass or less, preferably 20% by mass. High solubility is preferable because a thicker film can be formed by coating.

The copolymer according to the present invention preferably has an appropriate interaction between molecules. In the present specification, the interaction between molecules means that the distance between polymer chains is shortened by an interaction such as π-π stacking between molecules. The stronger the interaction, the higher the mobility and / or crystallinity, and the more suitable the semiconductor material is. That is, in a copolymer that interacts between molecules, electron transfer between molecules is likely to occur. For example, when the copolymer according to the present invention is used in an active layer in a photoelectric conversion element, a p-type semiconductor compound in the active layer is used. It is considered that holes generated at the interface between the n-type semiconductor compound and the n-type semiconductor compound can be efficiently transported to the electrode (anode).

An example of the crystallinity measuring method is X-ray diffraction (XRD). In this specification, having crystallinity means that an X-ray diffraction spectrum obtained by XRD measurement has a diffraction peak. Having crystallinity is considered to mean that it has a laminated structure in which molecules are arranged, and is preferable in that the active layer described later tends to be thickened. XRD measurement can be performed based on a method described in a known document (X-ray crystal analysis guide (applied physics selection book 4)).

The hole mobility (sometimes referred to as hole mobility) of the copolymer according to the present invention is usually 1.0 × 10 ⁻⁷ cm ² / Vs or more, preferably 1.0 × 10 ⁻⁶ cm ² / Vs or more. More preferably, it is 1.0 × 10 ⁻⁵ cm ² / Vs or more, and particularly preferably 1.0 × 10 ⁻⁴ cm ² / Vs or more. On the other hand, the hole mobility of the copolymer according to the present invention is usually 1.0 × 10 ⁴ cm ² / Vs or less, preferably 1.0 × 10 ³ cm ² / Vs or less, and more preferably 1.0 × 10 6. ² cm ² / Vs or less, particularly preferably 1.0 × 10 cm ² / Vs or less. When the hole mobility is in this range, the copolymer according to the present invention is suitably used as a semiconductor material. Further, in order to obtain high conversion efficiency in the photoelectric conversion element, it is important to balance the mobility of the n-type semiconductor compound and the mobility of the p-type semiconductor compound. When the copolymer according to the present invention is used as a p-type semiconductor compound in a photoelectric conversion element, from the viewpoint of bringing the hole mobility of the copolymer according to the present invention close to the electron mobility of the n-type semiconductor compound, the copolymer according to the present invention is positive. The hole mobility is preferably within this range. As a method for measuring the hole mobility, there is an FET method. The FET method can be performed by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

The copolymer according to the present invention preferably has high storage stability in a solution state. High storage stability means that it is difficult to aggregate when made into a solution. More specifically, 2 mg of the copolymer according to the present invention was placed in a 2 mL screw vial, dissolved in o-xylene to a concentration of 1.5% by mass, and then cooled to room temperature. Then, it is preferable not to gel for 5 minutes or more, and it is more preferable not to gel for 1 hour or more.

The impurities in the copolymer according to the present invention are preferably as small as possible. In particular, when a copolymer having a repeating unit represented by the formula (I) is synthesized, when a transition metal catalyst such as palladium or copper is used, these may remain in the copolymer. If these metal catalysts remain in the copolymer, exciton traps due to the heavy atom effect of the transition metal occur and charge transfer is inhibited. As a result, when the copolymer according to the present invention is used in a photoelectric conversion element, There is a risk of reducing the conversion efficiency. Therefore, the concentration of the transition metal catalyst is usually 1000 ppm or less, preferably 500 pm or less, more preferably 100 ppm or less per 1 g of copolymer. On the other hand, it is usually larger than 0 ppm and may be 1 ppm or more, or 3 ppm or more.

The impurities contained in the copolymer can be measured by, for example, ICP mass spectrometry. ICP mass spectrometry can be carried out by a method described in a known document (“Plasma ion source mass spectrometry” (Academic Publishing Center)). Specifically, for palladium atoms and copper atoms, after the sample is wet-decomposed, Pd and Sn in the decomposition solution are obtained by a calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies). It can be quantified.

<2. Method for producing copolymer according to the present invention>
The method for producing the copolymer of the present invention is not particularly limited. The compound represented by the following formula (VII), the compound represented by the following formula (VIII), and the compound represented by the following formula (IX): A method of polymerizing a compound represented by the following formula (X) in the presence of a suitable catalyst if necessary. In the case of producing a copolymer in which A1 in formula (I) and A2 in formula (II) are the same, a compound represented by the following formula (VII) and a compound represented by the following formula (VIII) And a compound represented by the following formula (IX) (or a compound represented by the following formula (X)) can be produced according to a polymerization reaction described later. In the case of producing a copolymer in which A1 in the formula (I) and A2 in the formula (II) are different, as an example, in advance, a compound represented by the following formula (VII) and the following formula (IX): Intermediate 1 obtained by polymerization reaction with the compound represented, Compound represented by the following formula (VIII), and Intermediate 2 obtained by polymerization reaction of the compound represented by the following formula (X) The copolymer which concerns on this invention can be manufactured by producing and synthesizing the intermediate body 1 and the intermediate body 2 by the polymerization reaction mentioned later.

In the above formula (VII), D has the same meaning as D in the above formula (I). In the above formula (VIII), L, R ¹ and R ² are as defined L in above-mentioned formula (II), and R ¹ and R ^2. In formula (IX), A1 has the same meaning as A1 in formula (I). In the above formula (X), A2 has the same meaning as A2 in the above formula (II).

Y1 to Y8 in the formulas (VII) to (X) can be appropriately selected according to the kind of the polymerization reaction and are not particularly limited, but are independently a halogen atom, an alkylstannyl group, or an alkylsulfo group. , Arylsulfo group, arylalkylsulfo group, boric acid ester residue, sulfonium methyl group, phosphonium methyl group, phosphonate methyl group, monohalogenated methyl group, boric acid residue (-B (OH) ₂ ), formyl group, An alkenyl group or an alkynyl group is represented.

The halogen atom is not particularly limited, but is preferably a bromine atom (Br) or an iodine atom (I).

The borate ester residue is not particularly limited, and examples thereof include a group represented by the following formula.

In the above formula, Me represents a methyl group, and Et represents an ethyl group.

The alkylstannyl group is not particularly limited, and examples thereof include a group represented by the following formula.

In the above formula, Me represents a methyl group, and Bu represents a butyl group.

The alkenyl group is not particularly limited, but for example, an alkenyl group having 2 to 12 carbon atoms is preferable.

Among the above, Y1 to Y8 are each independently a halogen atom, an alkylstannyl group, from the viewpoint of the synthesis of the compounds represented by formulas (VII) to (X) and the ease of reaction. A boric acid ester residue or a boric acid residue (—B (OH) ₂ ) is preferable.

Examples of the reaction method used for polymerization of the copolymer of the present invention include Suzuki-Miyaura cross-coupling reaction method, Stille coupling reaction method, Yamamoto coupling reaction method, Grignard reaction method, Heck reaction method, Sonogashira reaction method, FeCl _{3 and the} like. A reaction method using an oxidizing agent, a method using an electrochemical oxidation reaction, a reaction method by decomposition of an intermediate compound having an appropriate leaving group, and the like. Among these, the Suzuki-Miyaura coupling reaction method, Stille coupling reaction method, Yamamoto coupling reaction method, and Grignard reaction method are preferable in terms of easy structure control. In particular, the Suzuki-Miyaura cross-coupling reaction method, the Stille coupling reaction method, and the Grignard reaction method are preferable from the viewpoint of easy availability of materials and easy reaction operation. These reactions include "cross coupling-basics and industrial applications-(CMC Publishing)", "transition metal catalyzed reactions for organic synthesis (written by Jiro Jiro: edited by the Society of Synthetic Organic Chemistry)", "for organic synthesis" The reaction can be carried out according to a method described in known literature such as “catalytic reaction 103 (Teijiro Hatakeyama: Tokyo Kagaku Dojin)”.

In addition, as described above, Y1 to Y8 in the formulas (VII) to (X) may be appropriately selected to carry out the polymerization reaction. For example, Y1 to Y4 in formula (VII) and formula (VIII) are alkylstannyl groups, and Y5 to Y8 in formula (IX) and formula (X) are used as halogen atoms to perform known Stille coupling reactions. What is necessary is just to react according to conditions. In addition, Y1 to Y4 in the formulas (VII) and (VIII) are known borate esters or boric acid residues, Y5 to Y8 in the formulas (IX) and (X) are halogen atoms, and known Suzuki. -The reaction may be performed according to the conditions of the Miyaura coupling reaction. Furthermore, Y1 to Y4 in formula (VII) and formula (VIII) are used as silyl groups, Y5 to Y8 in formula (IX) and formula (X) are used as halogen atoms, and the reaction is carried out according to known Hiyama coupling reaction conditions. Just do it. As a catalyst for the coupling reaction, for example, a combination of a transition metal such as palladium and a ligand (for example, a phosphine ligand such as triphenylphosphine) can be used.

Further, it is preferable to further end-treat the copolymer obtained by the polymerization reaction. By performing the terminal treatment of the copolymer, the residual amount of the terminal residues (Y1 to Y8 described above) can be reduced. By performing such a terminal treatment, halogen atoms, alkylstannyl groups, and the like in the obtained copolymer can be reduced. Therefore, when the copolymer according to the present invention is used for a photoelectric conversion element, conversion efficiency and durability are improved. This is preferable because of improved properties.

In addition, after the polymerization reaction, a process for separating the copolymer is usually performed. When the terminal treatment of the copolymer is performed, it is preferable to perform a step of separating the copolymer after the terminal treatment. If necessary, further copolymer separation and purification may be performed prior to copolymer termination. From the viewpoint of obtaining the copolymer in a shorter processing step, it is preferable to carry out the terminal treatment of the copolymer, separation of the copolymer and purification of the copolymer in this order after the polymerization reaction.

As a method for separating the copolymer, for example, the reaction solution and a poor solvent are mixed to precipitate the copolymer, or the active species in the reaction solution is quenched with water or hydrochloric acid, and then the copolymer is extracted with an organic solvent. Examples include a method of distilling off the organic solvent.

Examples of the purification method of the copolymer include known methods such as reprecipitation purification, extraction using a Soxhlet extractor, gel permeation chromatography, or metal removal using a scavenger.

<2-1. Method for producing compounds represented by formula (VII) to formula (X)>
The method for producing the compounds represented by formulas (VII) to (X) is not particularly limited, but can be carried out with reference to known examples. Known examples include Polymer, 1990, 31, 1379-1383, Adv. Mater. , 2007, 19, 4160-4165, Macromolecules, 2010, 43, 6936-6938, Adv. Mater. , 2011, 23, 3315-3319, Angew. Chem. Int. Ed. 2012, 51, 2068-2071, J. MoI. Mater. Chem. 2011, 21, 3895-3902, J. MoI. Am. Chem. Soc. , 2011, 133, 10062-10065 or Chem. Commun. , 2011, 47, 4920, International Publication No. 2013/180243, and the like.

<3. Photoelectric conversion element>
The copolymer according to an embodiment of the present invention can be used as a material for a photoelectric conversion element. Specifically, the active layer of the photoelectric conversion element contains the copolymer according to the present invention, thereby providing high exposure stability. It can be a photoelectric conversion element. Hereinafter, an embodiment of a photoelectric conversion element using the copolymer according to the present invention will be described.

The photoelectric conversion element according to an embodiment of the present invention includes at least a base material, a pair of electrodes formed on the base material, and an active layer formed between the pair of electrodes. Hereinafter, an embodiment of a photoelectric conversion element according to the present invention will be described with reference to FIG.

As shown in FIG. 1, one embodiment of the photoelectric conversion element according to the present invention includes a lower electrode 101, a lower buffer layer 102, an active layer 103, an upper buffer layer 104, and an upper electrode on a substrate 106. 105 have a layer structure in which are sequentially formed. In the present invention, the lower electrode means an electrode laminated on the substrate 106 side, and the upper electrode means an electrode laminated above the lower electrode when the substrate 106 is used as the bottom. . In the present invention, the lower electrode 101 and the upper electrode 105 may be collectively referred to as a pair of electrodes. In addition, the lower buffer layer 102 and the upper buffer layer 104 are not essential components, and may be provided arbitrarily, and may include only one of the lower buffer layer 102 and the upper buffer layer 104. Moreover, the photoelectric conversion element may optionally have another layer other than the above. Hereinafter, each component of the photoelectric conversion element will be described.

<3-1. Substrate 106>
The photoelectric conversion element 107 is usually formed on a base material 106 that serves as a support. There is no particular limitation on the material of the substrate 106.
Preferable examples of the material of the substrate 106 include inorganic materials such as quartz, glass, sapphire, and titania, and flexible substrates. Specific examples of the flexible substrate include, but are not limited to, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluororesin film, vinyl chloride. Or polyolefin such as polyethylene; organic material (resin substrate) such as cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, or epoxy resin; paper material such as paper or synthetic paper; stainless steel, Examples thereof include composite materials such as a metal foil such as titanium or aluminum whose surface is coated or laminated in order to impart insulation. Examples of the glass include soda glass, blue plate glass, and non-alkali glass. Among these, alkali-free glass is preferable in that there are few eluted ions from the glass.
For the shape, configuration and the like of the base material 106, known techniques can be referred to. Specifically, for example, publicly known documents such as International Publication No. 2011-016430 or Japanese Unexamined Patent Application Publication No. 2012-191194 are available. Those described can be adopted.

<3-2. Pair of electrodes (lower electrode 101 and upper electrode 105)>
The pair of electrodes (101, 106) has a function of collecting holes and electrons generated by light absorption. Accordingly, the pair of electrodes includes an electrode suitable for collecting holes (hereinafter sometimes referred to as an anode) and an electrode suitable for collecting electrons (hereinafter sometimes referred to as a cathode). It is preferable to use it. Any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Further, the solar light transmittance of the transparent electrode is preferably 70% or more in order to allow light to reach the active layer through the transparent electrode. The light transmittance can be measured with a normal spectrophotometer.

The anode is an electrode generally made of a conductive material having a work function higher than that of the cathode and having a function of smoothly extracting holes generated in the active layer.
The material of the anode is not particularly limited. For example, conductive metal oxide such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide, or zinc oxide. A metal such as gold, platinum, silver, chromium or cobalt, or an alloy thereof. These substances are preferable because they have a high work function, and further, a conductive polymer material represented by PEDOT: PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid can be stacked. When laminating such a conductive polymer, the work function of this conductive polymer material is high, so even if it is not a material with a high work function as described above, it is suitable for cathodes such as Al and Mg. Metals can also be widely used. PEDOT: PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid, or a conductive polymer material in which polypyrrole, polyaniline, or the like is doped with iodine or the like can also be used as an anode material.
When the anode is a transparent electrode, it is preferable to use a light-transmitting conductive metal oxide such as ITO, zinc oxide or tin oxide, and ITO is particularly preferable.

The cathode is generally an electrode made of a conductive material having a low work function, and having a function of smoothly extracting electrons generated in the active layer 103. The cathode is adjacent to the electron extraction layer.
The material of the cathode is not particularly limited. For example, metals such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium or magnesium and alloys thereof; Inorganic salts such as lithium fluoride and cesium fluoride; metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. These materials are preferable because they are materials having a low work function. Similarly to the anode, a material having a high work function can be used for the cathode by using an n-type semiconductor such as titania having conductivity as the electron extraction layer. From the viewpoint of electrode protection, the cathode material is preferably a metal such as platinum, gold, silver, copper, iron, tin, aluminum, calcium or indium, or an alloy using these metals such as indium tin oxide.

Regarding physical properties such as sheet resistance of anode and cathode materials, composition, and manufacturing method thereof, well-known techniques can be referred to. Specifically, for example, International Publication No. 2011-016430 or Japanese Unexamined Patent Application Publication No. 2012. Those described in publicly known documents such as -191194 can be employed.

<3-3. Active layer 103>
The active layer 103 is a layer that contains a p-type semiconductor compound and an n-type semiconductor compound and undergoes photoelectric conversion. Specifically, when the photoelectric conversion element 107 receives light, the light is absorbed by the active layer 103, electricity is generated at the interface between the p-type semiconductor material and the n-type semiconductor material, and the generated electricity is extracted from the anode and the cathode. It is.

As the layer structure of the active layer 103, a thin film stack type in which a layer containing a p-type semiconductor compound and a layer containing an n-type semiconductor compound are stacked, or a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed is used. A bulk heterojunction type. Note that the bulk heterojunction active layer may have a structure in which a layer containing a p-type semiconductor compound and / or a layer containing an n-type semiconductor compound is further stacked in addition to the mixed layer. From the viewpoint that high photoelectric conversion efficiency can be expected, a bulk heterojunction type is preferable.

The active layer 103 contains at least a copolymer according to an embodiment of the present invention as a p-type semiconductor compound. When the active layer 103 contains the copolymer according to the present invention, a photoelectric conversion element having high conversion efficiency and high exposure stability can be obtained.

The active layer 103 may contain other p-type semiconductor compounds in addition to the copolymer according to the present invention as long as the effects according to the present invention are not impaired. The other p-type semiconductor compound may be a low molecular organic compound or a high molecular compound. These p-type semiconductor compounds are not particularly limited, but for example, those described in known literatures such as International Publication No. 2011-016430 or Japanese Unexamined Patent Publication No. 2012-191194 can be used.

The n-type semiconductor compound is not particularly limited. For example, a fullerene compound; a quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum; a condensed ring tetracarboxylic acid such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide. Acid diimides; perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzthiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, Triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives Bipyridine derivatives, borane derivatives; anthracene, pyrene, total fluoride condensed polycyclic aromatic hydrocarbons such as naphthacene or pentacene; single-walled carbon nanotubes, n-type polymer (n-type polymer semiconductor material), and the like.

Among them, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides, N-alkyl substituted perylene diimide derivatives or n-type polymer semiconductor materials are preferred. More preferred are fullerene compounds, N-alkyl substituted perylene diimide derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides or n-type polymer semiconductor compounds, and fullerene compounds are particularly preferred. These compounds are not particularly limited, but for example, those described in known literatures such as International Publication No. 2011-016430 or Japanese Unexamined Patent Publication No. 2012-191194 can be used. In addition, a kind of compound may be used among the above, and a mixture of a plurality of kinds of compounds may be used. Among these, it is particularly preferable to use 60 PCBM, 70 PCBM or a mixture thereof.

The thickness of the active layer 103 is not particularly limited, but is usually 10 nm or more, preferably 50 nm or more, usually 1 μm or less, preferably 500 nm or less, more preferably 200 nm or less. A thickness of the active layer 103 of 10 nm or more is preferable because the uniformity of the film is maintained and a short circuit is hardly caused. In addition, it is preferable that the thickness of the active layer 103 is 1 μm or less because the internal resistance is reduced, and further, the charge diffusion is improved without the pair of electrodes being separated too much.

The method for forming the active layer 103 is not particularly limited, but is preferably formed by a coating method because productivity is improved. Specifically, the active layer 103 is preferably formed by applying an active layer forming ink containing a copolymer according to the present invention.

As the coating method, any method can be used. For example, spin coating method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe Examples include a doctor method, an impregnation / coating method, and a curtain coating method.

When forming a laminated type active layer, an active layer forming ink containing at least a copolymer according to the present invention as a p-type semiconductor compound and an active layer ink containing an n-type semiconductor compound are used, respectively, by a coating method. An active layer may be formed by stacking a p-type semiconductor-containing layer and an n-type semiconductor-containing layer. On the other hand, when forming a bulk hetero type active layer, an active layer forming ink containing at least a copolymer according to the present invention and an n type semiconductor compound as a p type semiconductor compound is used, and a bulk hetero type active layer is formed by a coating method. An active layer may be formed.

The above-described ink for forming an active layer usually contains a solvent in addition to the above-described compound. The solvent is not particularly limited, but for example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; aromatic such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene Hydrocarbons; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; lower alcohols such as methanol, ethanol or propanol; acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone Aliphatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; chloroform, Methylene, dichloroethane, halogenated hydrocarbons such as trichloroethane or trichlorethylene; ethers such as ethyl ether and tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide, and the like.

Among them, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; cycloaliphatic carbonization such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin Hydrogens; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene; or ethers such as ethyl ether, tetrahydrofuran or dioxane. More preferably, non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene; non-halogen ketones such as cyclopentanone or cyclohexanone; aromatic ketones such as acetophenone or propiophenone; tetrahydrofuran, cyclohexane Alicyclic hydrocarbons such as pentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; or non-halogens such as 1,4-dioxane Aliphatic ethers. Particularly preferred are non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene.

As the solvent, one type of solvent may be used alone, or any two or more types of solvents may be used in an arbitrary ratio. When two or more kinds of solvents are used in combination, it is preferable to combine a low boiling point solvent having a boiling point of 60 ° C. or higher and 150 ° C. or lower and a high boiling point solvent having a boiling point of 180 ° C. or higher and 250 ° C. or lower. Examples of combinations of low and high boiling solvents include non-halogen aromatic hydrocarbons and alicyclic hydrocarbons, non-halogen aromatic hydrocarbons and aromatic ketones, ethers and alicyclic carbonization. Examples thereof include hydrogens, ethers and aromatic ketones, aliphatic ketones and alicyclic hydrocarbons, or aliphatic ketones and aromatic ketones. Specific examples of preferred combinations include toluene and tetralin, xylene and tetralin, toluene and acetophenone, xylene and acetophenone, tetrahydrofuran and tetralin, tetrahydrofuran and acetophenone, methyl ethyl ketone and tetralin, methyl ethyl ketone and acetophenone, and the like.

The active layer forming ink may contain other additives in addition to the compounds described above as long as the effects according to the present invention are not impaired.

<3-4. Lower buffer layer 102, upper buffer layer 104>
As described above, the photoelectric conversion element according to this embodiment includes the lower buffer layer 102 between the lower electrode 101 and the active layer 103, and the upper buffer layer 104 between the upper electrode 105 and the active layer 103. . The lower buffer layer 102 and the upper buffer layer 104 each have a function of improving the electron extraction efficiency from the active layer 103 to the cathode or the hole extraction efficiency from the active layer 103 to the anode. Note that a buffer layer having a function of improving the electron extraction efficiency from the active layer 103 to the cathode is referred to as an electron extraction layer, and a buffer layer having a function of improving the electron extraction efficiency from the active layer 103 to the cathode is referred to as a hole extraction layer. As described above, the lower buffer layer 102 and the upper buffer layer 104 are not essential components, and the organic thin film solar cell element 4 may not include the lower buffer layer 102 and the upper buffer layer 104. Moreover, you may have only any one layer.

Either the lower buffer layer 102 or the upper buffer layer 104 may be an electron extraction layer or a hole extraction layer, but when the lower electrode 101 is a cathode and the upper electrode 105 is an anode, the lower buffer layer 102 is an electron extraction layer. The upper buffer layer 104 is a hole extraction layer. On the other hand, when the lower electrode 101 is an anode and the upper electrode 105 is a cathode, the lower buffer layer 102 is a hole extraction layer and the upper buffer layer 104 is an electron extraction layer.

<3-4-1. Electron extraction layer>
The material of the electron extraction layer is not particularly limited as long as it is a material that improves the efficiency of extracting electrons from the active layer 103 to the cathode, and examples thereof include inorganic compounds and organic compounds.
Examples of inorganic compounds include salts of alkali metals such as Li, Na, K or Cs; n-type semiconductor oxides such as titanium oxide (TiOx) and zinc oxide (ZnO). Among them, the alkali metal salt is preferably a fluoride salt such as LiF, NaF, KF or CsF, and the n-type semiconductor oxide is preferably zinc oxide (ZnO). Although the operation mechanism of such a material is unknown, it is conceivable to reduce the work function of the cathode when combined with a cathode made of Al or the like and increase the voltage applied to the solar cell element.
Examples of organic compounds include phosphine compounds having a double bond between a phosphorus atom and a group 16 element such as triarylphosphine oxide compounds; substituents such as bathocuproin (BCP) or bathophenanthrene (Bphen) A phenanthrene compound in which the 1-position and the 10-position may be substituted with a heteroatom; a boron compound such as triarylboron; an organometallic such as (8-hydroxyquinolinato) aluminum (Alq3) Oxide; Compound having 1 or 2 ring structure which may have a substituent such as oxadiazole compound or benzimidazole compound; naphthalenetetracarboxylic anhydride (NTCDA) or perylenetetracarboxylic anhydride Such as (PTCDA), such as dicarboxylic anhydride Aromatic compounds having a slip dicarboxylic acid structure.
As for the physical properties, the configuration of the material of the electron extraction layer, and the manufacturing method thereof, well-known techniques can be referred to. Specifically, for example, International Publication No. 2013/180243, International Publication No. 2011-016430 or Japan Those described in publicly known documents such as Japanese Unexamined Patent Publication No. 2012-191194 can be adopted.

<3-4-2. Hole extraction layer>
The material for the hole extraction layer is not particularly limited as long as it is a material capable of improving the efficiency of extracting holes from the active layer 103 to the anode.
Specifically, conductive polymers in which polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, etc. are doped with sulfonic acid and / or iodine, polythiophene derivatives having a sulfonyl group as a substituent, conductive organics such as arylamine Examples thereof include compounds, copper oxide, nickel oxide, manganese oxide, molybdenum oxide, vanadium oxide, metal oxide such as tungsten oxide, Nafion, and a p-type semiconductor described later. Among them, a conductive polymer doped with sulfonic acid is preferable, and (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. It is. A thin film of metal such as gold, indium, silver or palladium can also be used. A thin film of metal or the like may be formed alone or in combination with the above organic material.
For the structure of the hole extraction layer and the method for producing the hole extraction layer, known techniques can be referred to. Specifically, for example, publicly known publications such as International Publication No. 2012/102390 or Japanese Unexamined Patent Publication No. 2012-191194 are known. Those described in the literature can be employed.

<3-5. Manufacturing method of photoelectric conversion element>
The photoelectric conversion element 107 having the configuration shown in FIG. 1 is formed on the base 106 by, for example, the lower electrode 101, the lower buffer layer 102, the active layer 103, and the upper buffer layer 104 by the method described in the above-described publicly known literature. , And the upper electrode 105 can be sequentially stacked. In the case of manufacturing the photoelectric conversion element having the tandem structure shown in FIG. 2, the lower electrode 101, the lower buffer layer 102, the first active layer 108, the intermediate layer 109, and the second active element are formed on the substrate 106. The layer 110, the upper buffer layer 104, and the upper electrode 105 can be sequentially stacked.

After laminating the lower electrode 101 and the upper electrode 105, the photoelectric conversion element is usually in a temperature range of 50 ° C. or higher, preferably 80 ° C. or higher, usually 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 250 ° C. or lower. It is preferable to heat (this step is referred to as an annealing treatment step).

Performing the annealing process at a temperature of 50 ° C. or higher improves adhesion between the layers of the photoelectric conversion element, for example, adhesion between the lower buffer layer 102 and the lower electrode 101 and / or the lower buffer layer 102 and the active layer 103. This is preferable because the effect of By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. In addition, the self-organization of the active layer can be promoted by the annealing process. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the possibility that the organic compound in the active layer 103 is thermally decomposed is reduced. In the annealing treatment step, stepwise heating may be performed within the above temperature range.

The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment step is preferably terminated when the open-circuit voltage, the short-circuit current, and the fill factor, which are parameters of the solar cell performance, reach a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere.

As a heating method, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be placed in a heating atmosphere such as an oven. The heating may be performed batchwise or continuously.

Although the thermal treatment and durability of the photoelectric conversion element can be improved by the annealing treatment step, the fullerene compound is aggregated during the annealing treatment step and phase separation is promoted, so that the photoelectric conversion efficiency may be lowered. . However, since the active layer 103 contains an additive, aggregation of the fullerene compound during the annealing process is suppressed by the additive. Thus, the photoelectric conversion element 107 with higher photoelectric conversion efficiency after performing an annealing process can be obtained by making the active layer 103 contain an additive.

Each layer constituting the photoelectric conversion element according to the present invention is not particularly limited, and can be formed by a sheet-to-sheet (manyoba) method or a roll-to-roll method. -It is preferable to form by a two-roll system.

The roll-to-roll method is a method in which a flexible base material wound in a roll shape is fed out and processed intermittently or continuously until it is taken up by a take-up roll. is there. According to the roll-to-roll method, it is possible to batch-process long substrates on the order of km, so that the production method is more suitable for mass production than the sheet-to-sheet method.

The size of the roll that can be used in the roll-to-roll method is not particularly limited as long as it can be handled by a roll-to-roll manufacturing apparatus, but the outer diameter is usually 5 m or less, preferably 3 m or less. Preferably, it is 1 m or less, usually 10 cm or more, preferably 20 cm or more, more preferably 30 cm or more. The outer diameter of the roll core is usually 4 m or less, preferably 3 m or less, more preferably 0.5 m or less, usually 1 cm or more, preferably 3 cm or more, more preferably 5 cm or more, still more preferably 10 cm or more, particularly preferably 20 cm or more. When these diameters are not more than the above upper limit, it is preferable in terms of high handleability of the roll, and when it is more than the lower limit, the layer formed in each of the following steps is less likely to be broken by bending stress. Is preferable. The width of the roll is usually 5 cm or more, preferably 10 cm or more, more preferably 20 cm or more, and is usually 5 m or less, preferably 3 m or less, more preferably 2 m or less. When the width is not more than the upper limit, it is preferable from the viewpoint of high handleability of the roll, and when the width is not less than the lower limit, the degree of freedom of the size of the photoelectric conversion element is preferable.

<3-6. Photoelectric conversion characteristics>
The photoelectric conversion characteristics of the photoelectric conversion element 107 can be obtained as follows. The photoelectric conversion element 107 is irradiated with light having an AM1.5G condition with a solar simulator at an irradiation intensity of 100 mW / cm ² , and current-voltage characteristics are measured. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.

The photoelectric conversion efficiency of the photoelectric conversion element according to the present invention is not particularly limited, but is usually 1% or more, preferably 1.5% or more, more preferably 2% or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better.

Moreover, as a method for measuring the durability of the photoelectric conversion element, a method for obtaining a maintenance ratio of the photoelectric conversion efficiency before and after exposing the photoelectric conversion element to the atmosphere can be mentioned.
(Maintenance rate) = (Photoelectric conversion efficiency after N hours of atmospheric exposure) / (Photoelectric conversion efficiency immediately before atmospheric exposure)

In order to put a photoelectric conversion element into practical use, it is important to have high photoelectric conversion efficiency and high durability in addition to simple and inexpensive manufacture. From this point of view, the maintenance rate of photoelectric conversion efficiency before and after exposure to the atmosphere for one week is preferably 60% or more, more preferably 75% or more, further preferably 80% or more, particularly preferably 85% or more, and high if high. Moderate.

<4. Solar cell>
The photoelectric conversion element according to the above-described embodiment is preferably used as a solar cell, particularly a solar cell element of a thin film solar cell. FIG. 2 is a cross-sectional view schematically showing the configuration of a thin-film solar cell as one embodiment of the present invention. As shown in FIG. 2, the thin film solar cell 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and a photoelectric conversion element. 6, a sealing material 7, a getter material film 8, a gas barrier film 9, and a back sheet 10 are provided in this order. And a thin film solar cell is normally irradiated with light from the side (downward in the figure) in which the weather-resistant protective film 1 was formed, and the photoelectric conversion element 6 generates electric power. Note that the thin-film solar cell does not need to have all of these constituent members, and each constituent member may be arbitrarily selected and provided.

There are no particular restrictions on these constituent members constituting the thin-film solar cell and the manufacturing method thereof, and well-known techniques can be used. For example, those described in known documents such as International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 can be used.

There is no particular limitation on the use of the solar cell according to the present invention, particularly the thin film solar cell 14 described above, and it can be used for any application. Examples include solar cells for building materials, solar cells for automobiles, solar cells for spacecrafts, solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like.

The solar cell according to the present invention, particularly a thin-film solar cell, may be used as it is, or for example, a solar cell may be installed on a substrate and used as a solar cell module. For example, as shown in FIG. 3, the solar cell module 13 having the thin film solar cell 14 on the base 12 can be installed and used at a place of use. For the substrate 12, well-known techniques can be used, for example, those described in International Publication No. 2011-016430 or Japanese Unexamined Patent Publication No. 2012-191194. For example, when a building material plate is used as the substrate 12, a solar cell panel can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of the plate.

Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. The items described in the examples were measured by the following methods.

[Method for measuring weight average molecular weight and number average molecular weight]
The polystyrene equivalent weight average molecular weight (Mw) and number average molecular weight (Mn) were determined by gel permeation chromatography (GPC). The molecular weight distribution (PDI) represents Mw / Mn.

Gel permeation chromatography (GPC) measurement was performed under the following conditions.
Column: PolymerLaboratories GPC column (PLgel MIXED-B 10 μm, inner diameter 7.5 mm, length 30 cm), connected in series Pump: LC-10AT (manufactured by Shimadzu Corporation)
Oven: CTO-10A (manufactured by Shimadzu Corporation)
Detector: Differential refractive index detector (manufactured by Shimadzu Corporation, RID-10A) and UV-vis detector (manufactured by Shimadzu Corporation, RID-10A) and UV-vis detector (manufactured by Shimadzu Corporation, SPD-10A)
Sample: 1 μL of 1 mg sample dissolved in orthodichlorobenzene (200 mg)
Mobile phase: orthodichlorobenzene Flow rate: 1.0 mL / min
Temperature: 80 ° C
Analysis: LC-Solution (manufactured by Shimadzu Corporation)

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 350 mg, 0.826 mmol), known literature (Polymer, 1990, 31, 1379) −1383), 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T1) (342 mg, 0.413 mmol), and international publication 4,4-bis (2-ethylhexyl) -2 obtained by referring to the method described in 2013/180243 -Bis (trimethyltin) -dithieno [3,2-b: 2 ', 3'-d] silole (compound E1) (308 mg, 0.413 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) ( 28.6 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 37.2 mg, 3 mol%), toluene (24 mL), and N, N-dimethylformamide (6 mL) The mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. After diluting the reaction solution 4 times with toluene and heating and stirring at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.036 mL) was added and heating and stirring at 100 ° C. for 5 hours. Bromobenzene (8 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 2 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was filtered off to obtain the target copolymer 1 in a yield of 74%. The weight average molecular weight Mw of the obtained copolymer 1 was 37 k, and PDI was 2.1.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 166 mg, 0.393 mmol), known literature (Polymer, 1990, 31, 1379) -1,383), 4,4′-dinonyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T2) (147 mg, 0.197 mmol), and international publication 4,4-bis (2-ethylhexyl) -2,6 obtained by referring to the method described in 2013/180243 Bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E1) (146 mg, 0.197 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (13) .6 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 17.7 mg, 3 mol%), toluene (12 mL), and N, N-dimethylformamide (3 mL) The mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. After the reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, as a terminal treatment, trimethyl (phenyl) tin (0.08 mL) was added and heated and stirred at 100 ° C. for 1 hour. Bromobenzene (4 mL) was further added, and the mixture was stirred with heating at 100 ° C. for 1 hr. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was filtered off to obtain the target copolymer 2 in a yield of 67%. The weight average molecular weight Mw of the obtained copolymer 2 was 62 k, and PDI was 1.8.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 167 mg, 0.395 mmol), known literature (Polymer, 1990, 31, 1379) −1383), 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T1) (197 mg, 0.237 mmol), and international publication 4,4-bis (2-ethylhexyl) -2 obtained by referring to the method described in 2013/180243 -Bis (trimethyltin) -dithieno [3,2-b: 2 ', 3'-d] silole (compound E1) (118 mg, 0.158 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) ( 13.7 mg, 3 mol%), a triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 17.8 mg, 3 mol%), toluene (12 mL), and N, N-dimethylformamide (3 mL) The mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. After the reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, as a terminal treatment, trimethyl (phenyl) tin (0.08 mL) was added and heated and stirred at 100 ° C. for 1 hour. Bromobenzene (4 mL) was further added, and the mixture was stirred with heating at 100 ° C. for 1 hr. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was filtered off to obtain the target copolymer 3 in a yield of 72%. The weight average molecular weight Mw of the obtained copolymer 3 was 50K, and PDI was 2.0.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 343 mg, 0.811 mmol), known literature (Polymer, 1990, 31, 1379) −1383), 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T1) (336 mg, 0.406 mmol), and international publication 4,4-Dioctyl-2,6-bis (trimethyl) obtained by referring to the method described in 2013/180243 Ruthin) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E2) (302 mg, 0.406 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (23.4 mg, 2.5 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 36.5 mg, 3 mol%), toluene (24 mL), and N, N-dimethylformamide (6 mL) The mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. After the reaction solution was diluted 4-fold with toluene and heated and stirred at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.16 mL) was added and heated and stirred at 100 ° C. for 2 hours. Bromobenzene (8 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 5 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 4 was obtained in a yield of 83%. The weight average molecular weight Mw of the obtained copolymer 4 was 66K, and PDI was 2.9.

<Synthesis Example 5: Synthesis of Copolymer 5>
[Synthesis Example: Synthesis of 4,4 ″ -didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″ -terthiophene (T4)]

In a 100 mL two-necked eggplant flask under a nitrogen atmosphere, 4,4 ″ -didodecyl-2, obtained by referring to non-patent literature (Angew. Chem. Int. Ed., 2012, 51, 2068-2071), 2 ′: 5 ′, 2 ″ -terthiophene (Compound T3) (1.20 g, 2.05 mmol) was added, dissolved in tetrahydrofuran (THF, 40.0 mL), and cooled to −78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentrations 1.13 M, 2.18 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 2.46 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.18 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 2.46 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling again to −78 ° C., a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.18 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 2.46 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to obtain 4,4 ″ -didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2 ′. : 5 ′, 2 ″ -terthiophene (Compound T4) was obtained quantitatively as a pale yellow solid. The compound was identified by proton NMR.

Compound T4: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.13 (s, 2H), δ 7.02 (s, 2H), δ 2.55 (t, 4H, J = 8.0 Hz), δ1 .62-1.55 (m, 4H), δ 1.40-1.22 (m, 36H), δ 0.88 (t, 6H, J = 7.2 Hz), δ 0.39 (s, 18H).
[Synthesis of Copolymer 5]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 140 mg, 0.330 mmol), 4,4 obtained by the method described above ″ -Didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″ -terthiophene (Compound T4) (154 mg, 0.169 mmol), and International Publication 2013/180243 4,4-dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] shiro (Compound E2) (126 mg, 0.169 mmol), tetrakis (triphenylphosphine) palladium (0) (11.7 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd— EnCatTPP30 (Aldrich, 15.2 mg, 1.83 mol%), toluene (10.0 mL), and N, N-dimethylformamide (2.50 mL) were added, followed by 1 hour at 100 ° C., followed by 5 at 110 ° C. Stir for hours. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 5 was obtained in a yield of 82.0%. The weight average molecular weight Mw of the obtained copolymer 5 was 15.2K, and PDI was 6.1.

<Synthesis Example 6: Synthesis of Copolymer 6>
[Synthesis Example: Synthesis of 4,3 ′, 4 ″ -tridodecyl-2,2 ′: 5 ′, 2 ″ -terthiophene (T7)]

4-dodecyl-2-trimethylstannylthiophene (Compound T5) (7.14 g) obtained by referring to a known document (Macromolecules, 2002, 35, 6883-6892) in a 50 mL two-necked eggplant flask under a nitrogen atmosphere , 17.2 mmol) and 2,5-dibromo-3-dodecylthiophene (compound T6) (2.54 g, 6.20 mmol), and tetrakis (triphenylphosphine) palladium (0) (100 mg, 1.40 mol%). ), Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 130 mg, 0.85 mol%), toluene (20.0 mL), and N, N-dimethylformamide (5.00 mL) 1 hour at 100 ° C, then 11 The mixture was stirred for 5 hours at ℃. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in hexane and subjected to column chromatography (acidic silica gel, hexane). By concentrating the solution, the desired 4,3 ′, 4 ″ -tridodecyl-2,2 ′: 5 ′, 2 ″ -terthiophene (Compound T7) was obtained in a yield of 45.0%. .

Compound T7: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 6.98 (d, 1 H, J = 1.2 Hz), δ 6.96 (s, 1 H), δ 6.94 (d, 1 H, J = 1.6 Hz), δ 6.87 (d, 1 H, J = 1.6 Hz), δ 6.78 (d, 1 H, J = 1.2 Hz), δ 2.71 (t, 2 H, J = 8.0 Hz), δ 2.62-2.55 (m, 4H), δ 1.65-1.60 (m, 6H), δ 1.40-1.20 (m, 54H), δ 0.88 (t, 9H, J = 7 .2 Hz).

[Synthesis Example: Synthesis of 4,3 ′, 4 ″ -Tridodecyl-5,5 ″ -bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″ -terthiophene (T8)]

In a 100 mL two-necked eggplant flask under a nitrogen atmosphere, 4,3 ′, 4 ″ -tridodecyl-2,2 ′: 5 ′, 2 ″ -terthiophene (T7) (2. 00 g, 2.66 mmol) was added, dissolved in tetrahydrofuran (THF, 50.0 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.82 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.19 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling again to −78 ° C., a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.82 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.19 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling again to −78 ° C., a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.82 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.19 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum, whereby 4,3 ′, 4 ″ -tridodecyl-5,5 ″ -bis (trimethylstannyl) -2 , 2 ′: 5 ′, 2 ″ -terthiophene (Compound T8) was quantitatively obtained as a pale yellow solid.

Compound T8: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.11 (s, 1H), δ 7.08 (s, 1H), δ 6.95 (s, 1H), δ 2.72 (t, 2H , J = 8.0 Hz), δ 2.59-2.53 (m, 4H), δ 1.67-1.56 (m, 6H), δ 1.40-1.20 (m, 54H), δ 0.88 (T, 9H, J = 7.2 Hz), δ 0.39 (s, 18H).

[Synthesis of Copolymer 6]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 140 mg, 0.330 mmol), 4,3 obtained by the method described above ', 4 ″ -Tridodecyl-5,5 ″ -bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″ -terthiophene (Compound T8) (182 mg, 0.169 mmol), and international publication 4,4-Dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-] obtained by referring to the method described in 2013/180243 ] Silole (Compound E2) (126 mg, 0.169 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (11.7 mg, 3.00 mol%), a triphenylphosphine-containing heterogeneous palladium complex catalyst Pd- EnCatTPP30 (Aldrich, 15.2 mg, 1.83 mol%), toluene (10.0 mL), and N, N-dimethylformamide (5.00 mL) were added, followed by 1 hour at 100 ° C., followed by 5 at 110 ° C. Stir for hours. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 6 was obtained in a yield of 82%. The weight average molecular weight Mw of the obtained copolymer 6 was 58K, and PDI was 2.4.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 138 mg, 0.33 mmol) and the method described in WO2013 / 180243 Compound E1 (255 mg, 0.34 mmol) obtained with reference to the above was added, and tetrakis (triphenylphosphine) palladium (0) (12 mg, 3 mol%), a triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 23 mg, 3 mol%) Toluene (5.3 mL), and N, placed N- dimethylformamide (1.3 mL), 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. After the reaction solution was diluted 4-fold with toluene and heated and stirred at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.3 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.5 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was filtered off to obtain the target copolymer 7 in a yield of 75%. The weight average molecular weight Mw of the obtained copolymer 7 was 137K, and PDI was 3.3.

<Synthesis Example 8: Synthesis of Copolymer 8>
[Synthesis Example: Synthesis of 4,4 ′ ″-didodecyl-2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene (T9)]

4-dodecyl-2-trimethylstannylthiophene (compound T5) (6.00 g) obtained by referring to a known document (Macromolecules, 2002, 35, 6883-6892) in a 50 mL two-necked eggplant flask under a nitrogen atmosphere , 13.6 mmol) and 5,5′-dibromo-2,2′-bithiophene (1.76 g, 5.43 mmol), and tetrakis (triphenylphosphine) palladium (0) (100 mg, 1.40 mol%). , Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 130 mg, 0.85 mol%), toluene (24.0 mL), and N, N-dimethylformamide (6.00 mL) 1 hour at 0 ° C, followed by 5 hours at 110 ° C It was. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in hexane and subjected to column chromatography (acidic silica gel, hexane). By concentrating the solution, the desired 4,4 ′ ″-didodecyl-2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene (Compound T9) was obtained in a yield. Obtained at 49.0%.

Compound T9: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.05 (s, 4H), δ 7.01 (s, 2H), δ 6.81 (s, 2H), δ 2.58 (t, 4H , J = 8.0 Hz), δ1.58-1.68 (m, 4H), δ1.26-1.40 (m, 36H), δ0.88 (t, 6H, J = 6.8 Hz).

[Synthesis Example: 4,4 ′ ″-didodecyl-5,5 ′ ″-bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene Synthesis of (T10)]

4,4 ′ ″-didodecyl-2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarter obtained by the above method in a 300 mL two-necked eggplant flask under nitrogen atmosphere Thiophene (T9) (1.69 g, 2.53 mmol) was added, dissolved in tetrahydrofuran (THF, 150.0 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.68 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 3.03 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.68 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 3.03 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.68 mL, 1.2 eq) was added dropwise, and the mixture was stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 3.03 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to obtain 4,4 ′ ″-didodecyl-5,5 ′ ″-bis (trimethylstannyl) -2, 2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene (Compound T10) was obtained quantitatively as a light orange solid.

Compound T10: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.17 (s, 4H), δ 7.13 (s, 1H), δ 6.93 (s, 1H), δ 2.58 (t, 4H , J = 8.0 Hz), δ1.58-1.68 (m, 4H), δ1.26-1.40 (m, 36H), δ0.88 (t, 6H, J = 6.8 Hz), δ0 .39 (s, 18H).
[Synthesis of Copolymer 8]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1) (imidothiophene dibromide) (140 mg, 0.330 mmol), 4,4 obtained as described above 4 ″ ′-didodecyl-5,5 ′ ″-bis (trimethylstannyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene (Compound T10) (100 mg , 0.101 mmol), and 4,4-dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-] obtained by referring to the method described in International Publication No. 2013/180243 b: 2 ′, 3′-d] silole (compound E2) (176 mg, 0.237 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (9.8 mg, 2.50 mol%), triphenylphosphine Containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 12.7 mg, 1.53 mol%), toluene (10.0 mL), and N, N-dimethylformamide (2.50 mL) at 100 ° C. The mixture was stirred for 1 hour and then at 110 ° C. for 5 hours. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 8 was obtained in a yield of 80%. The weight average molecular weight Mw of the obtained copolymer 8 was 46K, and PDI was 2.4.

<Synthesis Example 9: Synthesis of Copolymer 9>
[Synthesis Example: Synthesis of 2,5-bis (4-dodecylthiophen-2-yl) -3,4-ethylenedioxythiophene (T11)]

4-dodecyl-2-trimethylstannylthiophene (compound T5) (6.00 g) obtained by referring to a known document (Macromolecules, 2002, 35, 6883-6892) in a 50 mL two-necked eggplant flask under a nitrogen atmosphere , 13.6 mmol) and 2,5-dibromo-3,4-ethylenedioxythiophene (1.63 g, 5.43 mmol), and tetrakis (triphenylphosphine) palladium (0) (100 mg, 1.40 mol%). ), Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 130 mg, 0.85 mol%), toluene (24.0 mL), and N, N-dimethylformamide (6.00 mL) 1 hour at 100 ° C, followed by 110 In and the mixture was stirred for 5 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in hexane and subjected to column chromatography (acidic silica gel, hexane). By concentrating the solution, the target 2,5-bis (4-dodecylthiophen-2-yl) -3,4-ethylenedioxythiophene (Compound T11) was obtained in a yield of 52.0%.

Compound T11: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.05 (s, 2H), δ 6.80 (s, 2H), δ 4.38 (s, 4H), δ 2.58 (t, 4H , J = 8.0 Hz), δ1.58-1.68 (m, 4H), δ1.26-1.40 (m, 36H), δ0.88 (t, 6H, J = 6.8 Hz).

[Synthesis Example: Synthesis of 2,5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -3,4-ethylenedioxythiophene (T12)]

In a 200 mL two-necked eggplant flask under a nitrogen atmosphere, 2,5-bis (4-dodecylthiophen-2-yl) -3,4-ethylenedioxythiophene (T11) (1.68 g) obtained by the above method was used. , 2.61 mmol) was dissolved in tetrahydrofuran (THF, 100.0 mL) and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.77 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.13 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.77 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.13 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 2.77 mL, 1.2 eq) was added dropwise, and the mixture was stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0M, 3.13 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer is dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to give 2,5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -3,4 -Ethylenedioxythiophene (compound T12) was obtained quantitatively as a light orange solid.

Compound T12: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 6.92 (s, 2H), δ 4.38 (s, 4H), δ 2.58 (t, 4H, J = 8.0 Hz), δ1 58-1.68 (m, 4H), δ1.26-1.40 (m, 36H), δ0.88 (t, 6H, J = 6.8 Hz), δ0.39 (s, 18H).
[Synthesis of Copolymer 9]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1) (imidothiophene dibromide) (140 mg, 0.330 mmol), 2, 5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -3,4-ethylenedioxythiophene (compound T12) (33 mg, 0.034 mmol) and described in WO2013 / 180243 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithie obtained by referring to the method [3,2-b: 2 ′, 3′-d] silole (compound E1) (113 mg, 0.152 mmol), 4,4-dioctyl-2,6-bis (trimethyltin) -dithieno [3,2- b: 2 ′, 3′-d] silole (compound E2) (113 mg, 0.152 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (9.8 mg, 2.50 mol%), triphenylphosphine Containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 12.7 mg, 1.53 mol%), toluene (10.0 mL), and N, N-dimethylformamide (2.50 mL) at 100 ° C. The mixture was stirred for 1 hour and then at 110 ° C. for 5 hours. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 9 was obtained in a yield of 78%. The weight average molecular weight Mw of the obtained copolymer 9 was 87K, and PDI was 2.5.

<Synthesis Example 10: Synthesis of Copolymer 10>
[Synthesis Example: Synthesis of 2,5-bis (4-dodecylthiophen-2-yl) -thienothiophene (T13)]

4-Dodecyl-2-trimethylstannylthiophene (Compound T5) (7.73 g) obtained by referring to a known document (Macromolecules, 2002, 35, 6883-6892) in a 50 mL two-necked eggplant flask under a nitrogen atmosphere , 18.6 mmol) and 2,5-dibromothieno [3,2-b] thiophene (2.08 g, 7.00 mmol), and tetrakis (triphenylphosphine) palladium (0) (100 mg, 1.40 mol%) , Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 130 mg, 0.85 mol%), toluene (24.0 mL), and N, N-dimethylformamide (6.00 mL) 1 hour at 0 ° C followed by 5 at 110 ° C During the mixture was stirred. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in hexane and subjected to column chromatography (acidic silica gel, hexane). By concentrating the solution, the target 2,5-bis (4-dodecylthiophen-2-yl) -thienothiophene (Compound T13) was obtained in a yield of 51.0%.

Compound T13: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.13 (s, 2H), δ 7.05 (s, 2H), δ 7.02 (s, 2H), δ 2.55 (t, 4H , J = 8.0 Hz), δ1.62-1.55 (m, 4H), δ1.40-1.22 (m, 36H), δ0.88 (t, 6H, J = 7.2 Hz).

[Synthesis Example: Synthesis of 2,5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -thienothiophene (T14)]

In a 50 mL two-necked eggplant flask under a nitrogen atmosphere, 2,5-bis (4-dodecylthiophen-2-yl) -thienothiophene (T13) (600 mg, 0.94 mmol) obtained by the above method was placed. Dissolved in tetrahydrofuran (THF, 20.0 mL) and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 1.00 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.12 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling again to −78 ° C., a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 1.00 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.12 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.13 M, 1.00 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.12 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to give 2,5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -thienothiophene ( Compound T14) was obtained quantitatively as a pale yellow solid.

Compound T14: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.17 (s, 2H), δ 7.14 (s, 2H), δ 2.55 (t, 4H, J = 8.0 Hz), δ1 .62-1.55 (m, 4H), δ 1.40-1.22 (m, 36H), δ 0.88 (t, 6H, J = 7.2 Hz), δ 0.39 (s, 18H).

[Synthesis of Copolymer 10]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1) (imidothiophene dibromide) (140 mg, 0.330 mmol), 2, 5-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -thienothiophene (Compound T14) (98 mg, 0.101 mmol) and obtained by referring to the method described in International Publication No. 2013/180243 4,4-Dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] shiro (Compound E2) (176 mg, 0.237 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (9.8 mg, 2.50 mol%), a triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 12.7 mg, 1.53 mol%), toluene (10.0 mL), and N, N-dimethylformamide (2.50 mL) were added, and then at 100 ° C. for 1 hour, followed by 110 ° C. for 5 hours. Stir. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 10 was obtained in a yield of 79%. The weight average molecular weight Mw of the obtained copolymer 10 was 72K, and PDI was 2.4.

<Synthesis Example 11: Synthesis of Copolymer 11>
[Synthesis Example: Synthesis of 1,4-bis (4-dodecylthiophen-2-yl) -benzene (T15)]

4-dodecyl-2-trimethylstannylthiophene (compound T5) (6.00 g) obtained by referring to a known document (Macromolecules, 2002, 35, 6883-6892) in a 50 mL two-necked eggplant flask under a nitrogen atmosphere , 13.6 mmol) and 1,4-dibromobenzene (1.28 g, 5.43 mmol), tetrakis (triphenylphosphine) palladium (0) (100 mg, 1.40 mol%), triphenylphosphine-containing heterogeneity Based palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 130 mg, 0.85 mol%), toluene (24.0 mL), and N, N-dimethylformamide (6.00 mL) were added at 100 ° C. for 1 hour, followed by Stir at 110 ° C. for 5 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in hexane and subjected to column chromatography (acidic silica gel, hexane). By concentrating the solution, the target 1,4-bis (4-dodecylthiophen-2-yl) -benzene (Compound T15) was obtained in a yield of 20.0%.

Compound T15: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.15 (s, 2H), δ 7.10 (s, 2H), δ 7.00 (s, 2H), δ 6.95 (s, 2H) ), Δ2.55 (t, 4H, J = 8.0 Hz), δ1.62-1.55 (m, 4H), δ1.40-1.22 (m, 36H), δ0.88 (t, 6H) , J = 7.2 Hz).

[Synthesis Example: Synthesis of 1,4-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -benzene (T16)]

Under a nitrogen atmosphere, 1,4-bis (4-dodecylthiophen-2-yl) -benzene (T15) (618 mg, 1.07 mmol) obtained by the above method was placed in a 50 mL two-necked eggplant flask, and tetrahydrofuran was added. (THF, 30.0 mL) was dissolved and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentrations 1.13 M, 1.13 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.28 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling again to −78 ° C., a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentrations 1.13 M, 1.13 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.28 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. After cooling to −78 ° C. again, a solution of lithium diisopropylamide (LDA) in tetrahydrofuran / hexane (manufactured by Kanto Chemical Co., Inc., concentrations 1.13 M, 1.13 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 1.28 mL, 1.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer is dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to give 1,4-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -benzene (compound T16) was obtained quantitatively as a white solid.

Compound T16: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.22 (s, 2H), δ 7.12 (s, 2H), δ 7.07 (s, 2H), δ 2.55 (t, 4H , J = 8.0 Hz), δ1.62-1.55 (m, 4H), δ1.40-1.22 (m, 36H), δ0.88 (t, 6H, J = 7.2 Hz), δ0 .39 (s, 18H).

[Synthesis of Copolymer 11]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1) (imidothiophene dibromide) (140 mg, 0.330 mmol), 4-bis (4-dodecyl-5-trimethylstannylthiophen-2-yl) -benzene (Compound T16) (31 mg, 0.034 mmol) and obtained by referring to the method described in International Publication No. 2013/180243 4,4-dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] silole Product E2) (226 mg, 0.304 mmol), tetrakis (triphenylphosphine) palladium (0) (9.8 mg, 2.50 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich) 12.7 mg, 1.53 mol%), toluene (10.0 mL), and N, N-dimethylformamide (2.50 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 5 hours. . The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 11 was obtained in a yield of 78%. The weight average molecular weight Mw of the obtained copolymer 11 was 54K, and PDI was 3.2.

4,6-Dibromo-3-fluoro-2-carboxylic acid- (2-ethylhexyl) obtained by referring to a method described in International Publication No. 2014/042091 as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere Ester) -thieno [3,4-b] thiophene (compound F2) (thienothiophene dibromide) (312 mg, 0.660 mmol), obtained with reference to known literature (Polymer, 1990, 31, 1379-1383) Reference is made to 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (Compound T1) (280 mg, 0.338 mmol) and the method described in International Publication No. 2013/180243 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithio [3,2-b: 2 ′, 3′-d] silole (compound E1) (252 mg, 0.338 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (19.6 mg, 2.50 mol) was added. %), A triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 25.5 mg, 1.53 mol%), toluene (20.0 mL), and N, N-dimethylformamide (5.00 mL) And stirred at 100 ° C. for 1 hour and then at 110 ° C. for 5 hours. The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 12 was obtained in a yield of 78%. The weight average molecular weight Mw of the obtained copolymer 12 was 83K, and PDI was 1.7.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 114 mg, 0.270 mmol), known literature (Polymer, 1990, 31, 1379) -1,383), 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T1) (114 mg, 0.135 mmol), and known literature Compound E3 (137 mg, 0.1) obtained by referring to the method described in (Japanese Patent No. 5292514) 5 mmol), tetrakis (triphenylphosphine) palladium (0) (5.6 mg, 1.8 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 10.1 mg, 1 0.5 mol%), toluene (8 mL), and N, N-dimethylformamide (2 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 5 hours. As a terminal treatment, trimethyl (phenyl) tin (0.05 mL) was added followed by 8 mL of toluene, and the mixture was further heated and stirred at 110 ° C. for 1 hour. Then, bromobenzene (1.4 mL) was added and the mixture was added at 110 ° C. for 5 hours. The mixture was heated and stirred, and the reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 13 was obtained in a yield of 82%. The weight average molecular weight Mw of the obtained copolymer 13 was 108K, and PDI was 2.6.

In a 50 mL two-necked eggplant flask under nitrogen atmosphere, Thieno [3,4-b] thiophene-2-carboxylic acid, 4 obtained as a monomer with reference to the method described in Japanese Patent Application Laid-Open No. 2013-28565. , 6-dibromo-3-fluoro-, 2-ethylhexyl ester (compound F2 (thienothiophene dibromide), 79.2 mg, 0.168 mmol), known literature (Polymer, 1990, 31, 1379-1383) The obtained 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (Compound T1) (71.1 mg, 0.084 mmol), and known literature (Macromolecules, 2014, 47,2250-2256 4,8-Bis (2-Ethylhexyloxy) [benzo1,2-b: 4,5-b ′] dithiophene (Compound E4) (308 mg, 0.413 mmol) was added, and tetrakis (tri Phenylphosphine) palladium (0) (4.8 mg, 2.5 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 6.5 mg, 2.5 mol%), toluene (6 mL) And N, N-dimethylformamide (1.5 mL) were added, the temperature was raised from 65 ° C. to 105 ° C., and the mixture was stirred at 115 ° C. for 2 hours. The reaction solution was diluted 4-fold with toluene and heated and stirred at 115 ° C. for another hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added and heated and stirred at 115 ° C. for 1 hour. Benzene (0.9 mL) was added and stirred with heating at 115 ° C. for 5 hours. Ethyl acetate was poured into the reaction solution, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred at room temperature for 30 minutes and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 14 in a yield of 18%. The weight average molecular weight Mw of the obtained copolymer 14 was 124 k, and PDI was 3.0.

1,3-Dibromo-5- (2-ethylhexyl) obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere was obtained as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F3 (imidothiophene dibromide), 57.1 mg, 0.135 mmol), known literature (Polymer, 1990, 31) 4,4′-didodecyl-5,5′-bis (trimethylstannyl) -2,2′-bithiophene (compound T1) (114 mg, 0.135 mmol) was added. Tetrakis (triphenylphosphine) palladium (0) (4.7 mg, 3.0 mol%), tri A heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 6.1 mg, 2.0 mol%), toluene (4 mL), and N, N-dimethylformamide (1 mL) were charged at 95 ° C. for 1 hour. Subsequently, the mixture was stirred at 110 ° C. for 5 hours. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added followed by 6 mL of toluene, and the mixture was further heated and stirred at 110 ° C. for 1 hour, and then further bromobenzene (1 mL) was added and heated and stirred at 110 ° C. for 2 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 15 was obtained in a yield of 40%. The weight average molecular weight Mw of the obtained copolymer 15 was 18K, and PDI was 1.8.

<Synthesis Example 16: Synthesis of Copolymer 16>
[Synthesis Example: Synthesis of 3,3′-didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2′-bithiophene (T18)]

3,3′-didodecyl-5,5 ″ -dibromo obtained in a 100 mL two-necked eggplant flask under a nitrogen atmosphere with reference to a method described in a known literature (Materials Chemistry 2009, 19, 3490-3499) -2,2'-bithiophene (T17) (3.00 g, 4.54 mmol) was added, dissolved in tetrahydrofuran (THF, 50.0 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of normal butyl lithium (nBuLi) (manufactured by Kanto Chemical Co., Inc., concentration 1.60 M, 6.24 mL, 2.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 9.99 mL, 2.2 eq) was added dropwise, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer is dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to give 3,3′-didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2′- Bithiophene (compound T18) was quantitatively obtained as a pale yellow liquid.

Compound T18: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.02 (s, 2H), δ 2.51 (t, 4H, J = 8.0 Hz), δ 1.62-1.50 (m, 4H), δ 1.40-1.22 (m, 36H), δ 0.88 (t, 6H, J = 7.2 Hz), δ 0.37 (s, 18H).

[Synthesis of Copolymer 16]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1) (imidothiophene dibromide) (122 mg, 0.288 mmol), 3,3 With reference to 3′-didodecyl-5,5 ″ -bis (trimethylstannyl) -2,2′-bithiophene (Compound T18) (122 mg, 0.147 mmol) and the method described in International Publication No. 2013/180243 4,4-dioctyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] silole obtained Compound E2) (109 mg, 0.147 mmol), tetrakis (triphenylphosphine) palladium (0) (10.2 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich) 13.3 mg, 1.83 mol%), toluene (8.00 mL), and N, N-dimethylformamide (2.00 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 5 hours. . The reaction solution was diluted twice with toluene and heated and stirred at 110 ° C. for another 0.5 hours, and then trimethyl (phenyl) tin (0.20 mL) was added as a terminal treatment and heated and stirred at 110 ° C. for 2.0 hours. Further, bromobenzene (4.00 mL) was added and stirred with heating at 110 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the target copolymer 16 was obtained in a yield of 82.0%. The weight average molecular weight Mw of the obtained copolymer 16 was 49.0K, and PDI was 2.2.

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 142.2 mg, 0.336 mmol), 5,5′-bis (trimethyl) Stanyl) -2,2′-bithiophene (Compound T19) (manufactured by Aldrich, 83.5 mg, 0.168 mmol), 4,4-bis obtained by referring to the method described in International Publication No. 2013/180243 (2-Ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E 1) (127.6 mg, 0.168 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (9.7 mg, 2.5 mol%), a triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 ( Aldrich, 12.7 mg, 2.5 mol%), toluene (10 mL), and N, N-dimethylformamide (2.5 mL) were added, and the mixture was heated from 85 ° C. to 105 ° C. and stirred. A solid insoluble in the organic solvent was precipitated in the system. This was filtered and washed with chloroform to obtain copolymer 17. Due to the low solubility, the molecular weight could not be measured.

<Synthesis Example 18: Synthesis of Copolymer 18>
[Synthesis Example: Synthesis of 3-dodecyl-2,2′-bithiophene (T20)]

2-Bromo-3-dodecylthiophene (1.65 g, 5.0 mmol) and 2-tributylstannylthiophene (2.8 g, 7.5 mmol) were placed in a 50 mL two-necked eggplant flask, and nitrogen substitution was performed three times. It was. Tetrakis (triphenylphosphine) palladium (0) (173 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 50 mg, 1 mol%), toluene (8 mL), and N, N -Dimethylformamide (2 mL) was added and stirred at 110 ° C for 5 hours. After cooling to room temperature, solids were removed by celite filtration, and hexane and water were added. The aqueous phase was extracted with hexane, the organic layer was washed once with water and brine, and dried over anhydrous sodium sulfate. After distilling off the solvent, 3-dodecyl-2,2′-bithiophene (Compound T20) was obtained as a transparent liquid in a yield of 66% by silica gel column chromatography.

[Synthesis Example: Synthesis of 3-dodecyl-5,5 ″ -bis (trimethylstannyl) -2,2′-bithiophene (T21)]

Under a nitrogen atmosphere, 3-dodecyl-2,2′-bithiophene (T20) (1.11 g, 3.32 mmol) obtained by the above-described method was placed in a 50 mL two-necked eggplant flask, and tetrahydrofuran (THF, 15.2. (0 mL) and cooled to -78 ° C. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by TIC, 1.0 M, 3.3 mL, 1.0 eq) was added dropwise. Subsequently, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.3 M, 2.5 mL, 1.0 eq) was added dropwise and stirred for 30 minutes. This operation was repeated 3 times, and the temperature was slowly raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer is dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum to give 3-dodecyl-5,5 ″ -bis (trimethylstannyl) -2,2′-bithiophene (compound T21) was obtained quantitatively as a clear liquid.

[Synthesis of Copolymer 18]

1,3-Dibromo-5- (n-octyl) was obtained in a 50 mL two-necked eggplant flask under a nitrogen atmosphere as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). ) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide), 142.1 mg, 0.336 mmol) and described in WO2013 / 180243 Compound E1 (127.6 mg, 0.168 mmol) and Compound T21 (113.2 mg, 0.168 mmol) obtained by referring to the above method were added, and nitrogen substitution was performed three times. Furthermore, tetrakis (triphenylphosphine) palladium (0) (9.6 mg, 2.5 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 12.7 mg, 1.5 mol%), Toluene (10 mL) and N, N-dimethylformamide (2.5 mL) were added, the temperature was raised from 65 ° C. to 100 ° C., and the mixture was stirred for 1 hour. After further stirring at 105 ° C. for 20 minutes, toluene (10 mL) and trimethyl (phenyl) tin (0.06 mL) were added, and the mixture was further heated and stirred at 105 ° C. for 1 hour. Bromobenzene (1 mL) was added and stirred with heating at 105 ° C. for 82 hours, and the reaction solution was cooled to room temperature. 2.5 g of Celite and 10 mL of chloroform were added and filtered through Celite. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred at room temperature for 30 minutes and passed through a short column of acidic silica gel. The solution was concentrated to give the desired copolymer 18 in 14% yield. The weight average molecular weight Mw of the obtained copolymer 17 was 60K, and PDI was 2.6.

<Example 1: Production of photoelectric conversion element 1>
Copolymer 1 obtained in Synthesis Example 1 as a p-type semiconductor compound, and a mixture of fullerene compounds PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester) as an n-type semiconductor compound (Frontier Carbon Co., Ltd., nanom spectra E123) was dissolved in a mixed solvent of o-xylene and tetralin (volume ratio 9: 1) in a nitrogen atmosphere to a concentration of 2.4% by mass. Note that the mass ratio of the p-type semiconductor compound to the n-type semiconductor compound was p-type semiconductor compound: n-type semiconductor compound = 1: 2. This solution was stirred and mixed on a hot stirrer at a temperature of 80 ° C. for 1 hour. The solution after stirring and mixing was filtered through a 1 μm polytetrafluoroethylene (PTFE) filter to obtain an ink for coating an active layer.

A glass substrate (manufactured by Geomatic Co., Ltd.) patterned with an indium tin oxide (ITO) transparent conductive film is subjected to ultrasonic cleaning with acetone, followed by ultrasonic cleaning with isopropanol, followed by drying with nitrogen blow and UV-ozone treatment. went.

Next, a mixed solvent of 2-methoxyethanol (Aldrich) and ethanolamine (Aldrich) at a concentration of 105 mg / mL of zinc (II) acetate dihydrate (Wako Pure Chemical Industries) (volume ratio 100: The solution (about 0.1 mL) dissolved in 3) was spin-coated at a speed of 3000 rpm, subjected to UV-ozone treatment, and then heated in an oven at 200 ° C. for 15 minutes to form an electron extraction layer.
The substrate on which the electron extraction layer was formed was brought into a glove box, heat-treated at 150 ° C. for 3 minutes in a nitrogen atmosphere, and after cooling, the ink for active layer application (0.12 mL) produced as described above was spin-coated. An active layer having a thickness of 200 nm was formed. Then, it heated at 140 degreeC for 10 minute (s) on the hotplate.
The substrate on which the active layer was formed was taken out of the glove box, allowed to stand in the atmosphere (25 ° C., humidity 1% or less) for 3 hours under light shielding, and then brought back into the glove box.
Further, a molybdenum trioxide (MoO ₃ ) film having a thickness of 1.5 nm is formed on the active layer as a hole extraction layer, and then a silver film having a thickness of 100 nm is formed as an upper electrode by resistance heating vacuum deposition. A 5 mm square photoelectric conversion element was produced by sequentially forming a film. The photoelectric conversion element 1 thus produced was evaluated by measuring the current-voltage characteristics as described above, and the photoelectric conversion efficiency (PCE) when the active layer was not exposed was obtained.

In addition, holes are taken out in the same manner as described above except that the substrate formed up to the active layer is taken out of the glove box and then left in the atmosphere (25 ° C., humidity 1% or less) for 3 hours under irradiation of a fluorescent lamp. A layer and an upper electrode were formed to produce a photoelectric conversion element. Thus, the value was calculated | required as the photoelectric conversion efficiency (PCE) of the photoelectric conversion element 1 when the active layer was exposed, when the conversion efficiency of the obtained photoelectric conversion element was exposed. In addition, the ratio of the photoelectric conversion efficiency (PCE) when the active layer was exposed to the photoelectric conversion efficiency (PCE) when the active layer was not exposed was defined as the PCE maintenance rate (%) at the time of exposure. The obtained results are shown in Table 1.

<Example 2: Production of photoelectric conversion element 2>
A photoelectric conversion element 2 was produced in the same manner as in Example 1 except that the copolymer 2 obtained in Synthesis Example 2 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 3: Production of photoelectric conversion element 3>
A photoelectric conversion element 3 was prepared in the same manner as in Example 1 except that the copolymer 3 obtained in Synthesis Example 3 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 4: Production of photoelectric conversion element 4>
A photoelectric conversion element 4 was produced in the same manner as in Example 1 except that the copolymer 4 obtained in Synthesis Example 4 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 5: Production of photoelectric conversion element 5>
A photoelectric conversion element 5 was produced in the same manner as in Example 1 except that the copolymer 5 obtained in Synthesis Example 5 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 6: Production of photoelectric conversion element 6>
A photoelectric conversion element 6 was produced in the same manner as in Example 1 except that the copolymer 6 obtained in Synthesis Example 6 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Comparative Example 1: Production of photoelectric conversion element 7>
A photoelectric conversion element 7 was produced in the same manner as in Example 1 except that the copolymer 7 obtained in Synthesis Example 7 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was changed. Asked. The obtained results are shown in Table 1.

<Example 7: Production of photoelectric conversion element 8>
A photoelectric conversion element 8 was produced in the same manner as in Example 1 except that the copolymer 8 obtained in Synthesis Example 8 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 8: Production of photoelectric conversion element 9>
A photoelectric conversion element 9 was produced in the same manner as in Example 1 except that the copolymer 9 obtained in Synthesis Example 9 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was changed. Asked. The obtained results are shown in Table 1.

<Example 9: Production of photoelectric conversion element 10>
A photoelectric conversion element 10 was produced in the same manner as in Example 1 except that the copolymer 10 obtained in Synthesis Example 10 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 10: Production of photoelectric conversion element 11>
A photoelectric conversion element 11 was produced in the same manner as in Example 1 except that the copolymer 11 obtained in Synthesis Example 11 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 11: Production of photoelectric conversion element 12>
A photoelectric conversion element 12 was produced in the same manner as in Example 1 except that the copolymer 12 obtained in Synthesis Example 12 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 12: Production of photoelectric conversion element 13>
A photoelectric conversion element 13 was produced in the same manner as in Example 1 except that the copolymer 13 obtained in Synthesis Example 13 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Example 13: Production of photoelectric conversion element 14>
A photoelectric conversion element 14 was produced in the same manner as in Example 1 except that the copolymer 14 obtained in Synthesis Example 14 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Comparative Example 2: Production of photoelectric conversion element 15>
A photoelectric conversion element 15 was produced in the same manner as in Example 1 except that the copolymer 15 obtained in Synthesis Example 15 was used instead of the copolymer 1 obtained in Synthesis Example 1. However, the copolymer 15 has low solubility and cannot form a uniform film. As a result, the copolymer 15 did not function as a photoelectric conversion element.

<Reference Example 1: Production of photoelectric conversion element 16>
A photoelectric conversion element 16 was produced in the same manner as in Example 1 except that the copolymer 16 obtained in Synthesis Example 16 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

<Comparative Example 3: Production of photoelectric conversion element 17>
A photoelectric conversion element 17 was produced in the same manner as in Example 1 except that the copolymer 17 obtained in Synthesis Example 17 was used instead of the copolymer 1 obtained in Synthesis Example 1. However, the copolymer 17 had low solubility and could not form a uniform film, and consequently did not function as a photoelectric conversion element.

<Reference Example 2: Production of photoelectric conversion element 18>
A photoelectric conversion element 18 was produced in the same manner as in Example 1 except that the copolymer 18 obtained in Synthesis Example 18 was used instead of the copolymer 1 obtained in Synthesis Example 1, and the photoelectric conversion efficiency (PCE) was increased. Asked. The obtained results are shown in Table 1.

In Examples 1 to 13, there was almost no difference in conversion efficiency between when the active layer was exposed and when it was not exposed. That is, the maintenance ratio before and after exposure showed a high value of 81% to 107%. On the other hand, in Comparative Example 1 using the copolymer 7 having only the partial structure of the formula (I), when the active layer is exposed, the conversion efficiency is greatly reduced as compared with the case where the active layer is not exposed. I understand that. In addition, when the copolymer according to Reference Example 1 containing a thiophene ring having a substituent at a position different from that of the present invention is exposed to the active layer, the conversion efficiency is greatly reduced as compared with the case where the active layer is not exposed. I understand that Similarly, the copolymer according to Reference Example 2 that does not have a thiophene ring in which a substituent is introduced at a specific position as in the present invention and only one of the thiophene rings has a substituent is also active when the active layer is exposed. It can be seen that the conversion efficiency is greatly reduced compared to the case where the layer was not exposed. Further, the copolymer according to Comparative Example 2 having only the partial structure of the formula (II) was not soluble and could not form a uniform film, and did not function as a photoelectric conversion element. Similarly, the copolymer according to Comparative Example 3, which does not have a thiophene ring having a substituent introduced at a specific position as in the present invention, cannot form a uniform film with low solubility, and can be used as a photoelectric conversion element. Didn't work. From the above, it can be seen that by using the copolymer according to the present invention having both the partial structures of formula (I) and formula (II), a photoelectric conversion element having excellent exposure resistance can be provided.
In addition, since the copolymer according to an embodiment of the present invention has high exposure stability, the conversion efficiency of the obtained photoelectric conversion element is reduced even if the active layer is exposed to light during the manufacturing process of the photoelectric conversion element. Can be prevented.

DESCRIPTION OF SYMBOLS 101 Lower electrode 102 Lower buffer layer 103 Active layer 104 Upper buffer layer 105 Upper electrode 106 Base material 107 Photoelectric conversion element 1 Weatherproofing protective film 2 UV cut film 3,9 Gas barrier film 4,8 Getter material film 5,7 Sealing material 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell unit 14 Thin film solar cell

Claims

A copolymer having a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II).

(In Formula (I), D represents a donor monomer unit, A1 represents an acceptor monomer unit. In Formula (II), A2 represents an acceptor monomer unit, and L represents a direct bond or a divalent monomer unit. R 1 and R 2 each independently represent a monovalent organic group, and the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) are the same as each other. Not a repeating unit.)
The copolymer according to claim 1, wherein D in the formula (I) is a structural unit represented by the following formula (III) or a structural unit represented by the following formula (XI).

(In formula (III), Ar 1 and Ar 2 each independently represent an aromatic ring which may have a substituent. X 1 represents Q 1 (R 3 ) (R 4 ) or Q 3. represents (R 10), Q 1 represents an atom selected from the periodic table group 14 element, R 3 and R 4 are each independently, .Q 3 represents a hydrogen atom or a monovalent organic group, Represents an atom selected from Group 15 elements of the periodic table, and R 10 represents a hydrogen atom or a monovalent organic group, X 2 represents a direct bond, an oxygen atom (O), a sulfur atom (S), N (R 5 ) or Q 2 (R 6 ) (R 7 ), Q 2 represents an atom selected from Group 14 elements of the periodic table, and R 5 to R 7 each represents a hydrogen atom or a monovalent organic group. To express.)

(In the formula (XI), Ar 3 and Ar 4 each independently represent an aromatic ring optionally having a substituent, and X 3 and X 4 each independently represent Q 4 (R 11 ). Q 4 represents an atom selected from Group 14 elements of the periodic table, and R 11 represents a hydrogen atom or a monovalent organic group.)
In the formula (I) and the formula (II), A1 and A2 are structural units represented by the following formula (XIV) or structural units represented by the following formula (XV), respectively. Item 3. The copolymer according to Item 1 or 2.

(In the formula (XIV), Ar 5 is an aromatic hydrocarbon ring which may have a substituent, an aliphatic heterocyclic ring which may have a substituent, or an aromatic which may have a substituent. X 5 represents an atom selected from Group 16 elements of the periodic table.

(In the formula (XV), Ar 6 represents an aromatic hydrocarbon ring that may have a substituent, an aliphatic heterocyclic ring that may have a substituent, or an aromatic that may have a substituent. X 6 and X 7 each independently represent a nitrogen atom (N) or Q 5 (R 12 ), Q 5 represents an atom selected from Group 14 elements of the Periodic Table, 12 represents a hydrogen atom or a monovalent organic group.)
The copolymer according to any one of claims 1 to 3, wherein A1 in the formula (I) and A2 in the formula (II) are the same.
In the formula (II), L is a direct bond, a divalent monocyclic aromatic heterocyclic group which may have a substituent, and a monocyclic which may have a substituent. The copolymer according to any one of claims 1 to 4, wherein the copolymer is one selected from the group consisting of divalent polycyclic aromatic heterocyclic groups to which aromatic heterocyclic groups are linked. .
6. A photoelectric conversion element comprising at least a pair of electrodes and an active layer between the pair of electrodes on a base material, wherein the active layer contains the copolymer according to claim 1. A photoelectric conversion element characterized by:
A solar cell having the photoelectric conversion element according to claim 6.
A solar cell module having the solar cell according to claim 7.